| T.R | Title | User | Personal
Name | Date | Lines |
|---|
| 33.1 | | PYRITE::WEAVER | | Fri Jan 25 1985 09:09 | 4 |
| I used to be, many years ago. I flew a fair number of Estes rockets
in my day.
-Dave
|
| 33.2 | | TUNDRA::BAGDY | | Fri Jan 25 1985 14:55 | 7 |
|
I was also at one time. I flew the Estes Renegade, and upon launch, the
"D" engine burned a half dollar sized hole in the deflector plate and
battery. Since then, I moved into the city (If you want to call Burlington,
Vermont a city) and archived my rocket's.
-mb
|
| 33.3 | | CASTOR::MCCARTHY | | Fri Jan 25 1985 22:38 | 6 |
| I used to be into model rockets. I've seen more of my dollars than I care
to think about disappear over yonder ridge in a high wind.
I still have a few of my rockets (some flown, some not) but the closest I've
come in recent years are the Parks water fueled rockets. (I buy a new one
every year).
|
| 33.4 | | CRVAX1::KAPLOW | | Fri Jun 14 1985 19:37 | 9 |
| I just got the word that a longtime model rocketeer has been chosen
as an astronaut. Dr. Jay Apt, an MIT alumnus, has just been named as a mission
specialist. He was with JPL for many years, and when their missions seemed
to dry up, he moved to NASA in Houston, managing Shuttle payloads. Jay has
been an NAR member for further back than my knowledge goes, and a member
of the NAR board of trustees (the governing body) for the past few years. He
is also a private pilot.
I guess this hobby CAN lead somewhere!
|
| 33.5 | | KATADN::GILLEY | | Thu Jul 18 1985 14:04 | 9 |
| I AM VERY INTERESTED IN FINDING OUT MORE ON THE SUBJECT.
I AM ESPECIALLY INTERESTED IN MINIATURE TELEMETRY PACKAGES THAT ANYONE
MAY HAVE COME UP WITH. I HAVE BEEN FLYING MODEL ROCKETS FOR ABOUT 20
YRS. AND ALSO WORKED AT THE SPACE CENTER FOR A FEW ON THE
REAL THING (SATURN IV'S). I AM CURRENTLY LOCATED IN AUGUSTA, ME. ABOUT AS
FAR AWAY FROM ANYONE INTERESTED IN SPACE TECHNOLOGY AS YOU CAN GET.
IF YOU KNOW OF ANY CLUBS IN THE AREA PLEASE LET ME KNOW.
THANKS PAUL GILLEY ASO/9AA DNEAST::HAWK1::GILLEY DTN 271-6661
|
| 33.6 | | ENGGSG::FLIS | | Mon Feb 17 1986 07:22 | 22 |
| You're in luck! I have created a VAX NOTES File devoted to the subject of
Model Rocketry. The conference can be accessed via ENGGSG::[ROCKETS]ROCKETRY.NOTES.
I have been involved in model rocketry for (lets see now... ...OH yea!) 21
years and going strong. My involvement in this hobby has included:
- Very low power models (1/4A engines)
- High power (E & F)
- Payloads & Telemetry
- Scale
- Gliders (R/C included)
- Competition
- Launchers and launch controlers
- Multistage & clusters
And much more.
Please join us, in the ROCKETRY Notes File for exciting discusions on these and
many other subjects.
regards,
jim
|
| 33.7 | Correction to .6 | ENGGSG::FLIS | | Tue Feb 18 1986 06:55 | 9 |
| RE: .6
Sorry, allow me to correct the location of the conference:
ENGGSG::USERB:[ROCKETS]ROCKETRY
thanx,
jim
|
| 33.8 | Serious rocket details | VERGA::KLAES | Quo vadimus? | Wed Dec 29 1993 15:36 | 133 |
| Article: 56
From: [email protected] (Ron Graham)
Newsgroups: sci.space.tech
Subject: Re: Performance/specs for launch vehicles
Date: 23 Dec 1993 10:26 EDT
Organization: NASA Lewis Research Center
Dick Pierce inquires about information on launch vehicles, to plug
into a launch profile simulation. I got the following info from
Newton, K. E. and R. C. Lea. _Titan IIIE/Centaur D-1T
Systems Summary_. Prepared by General Dynamics Convair
and Martin Marietta Aerospace under contracts NAS3-13514
and NAS3-16082, September 1973.
So this isn't very new. But my office-mate has many such reports,
from years of working launch vehicle control dynamics. I am just
getting back into that business myself, after three years of Fred
and one of writing a Doctoral thesis.
Solid rocket motor: weight 500K lbf, thrust 1.2M lbf, burn 117 sec
(for each of two), Isp 266 sec.
Titan first stage: empty weight 15K lbf, propellants 262K lbf,
thrust 520K lbf, burn 146 sec, Isp 301 sec (vacuum).
Core second stage: empty weight 6K lbf, propellants 77K lbf, thrust
101K lbf and burn 210 sec, Isp 319 sec (vacuum).
Centaur: thrust 30K lbf, Isp 444 sec (vacuum).
Now, here's a little more recent stuff from
Benson, S. W., B. A. Beaver, A. L. Edelman and E. H. Sholes.
"Titan III Feasibility for HL-20 Prototype Missions."
_Journal of Spacecraft & Rockets_, Vol. 30, #5, pp. 615-621,
Sept.-Oct. 1993.
(Amy works a couple doors down the hall.)
After liftoff, the maximum axial force coefficient is about 2.5 and
occurs for a Mach number of about 1.25. Maximum aerodynamic loads
(commonly referred to as "Max Q") occurred at about Mach 1.75 and had
a value of about 2100 lbf/ft^2-deg (which considers the angle of attack).
The Q was 1000 lbf/ft^2. This article doesn't give vehicle weights,
and the other doesn't give payload info, but I see no reason that you
can't match up the two pieces of info to create a reasonable "typical
Titan."
RG
LeRC's first (and hopefully last) "valley Bajoran"
Article: 72
From: [email protected] (George George)
Newsgroups: sci.space.tech
Subject: Re: Performance/specs for launch vehicles
Date: Mon, 27 Dec 1993 14:12:40 -0500
Organization: Morgan Stanley - IS
Sender: [email protected]
There is a remarkable book written & published by Peter Alway. It
is called "Rockets of the World". It contains a write-up on every
major scientific/civilian/sounding/space launch rocket ever built.
That's for the entire *world*! Each chapter covers a different nation.
Multi-national projects are also included. No weapon systems are
covered - no sidewinders, Minute Men, Polaris - just the kind
of stuff we're into here on this newsgroup.
The book is geared towards model rocketeers. It's designed to give
you all the data you need to know to build scale models of the
subjects covered - there's scale drawings, painting guides, etc.
There is a wealth of additional information in there, including
most of what you're asking for. It's also a *really* good read.
The book assumes the reader is a seasoned rocket fan. No time is
wasted going over stuff we already know. The book concentrates on
the little details every other book ignores. Want to know how the
nose cone of an Aerobee-Hi was jettisoned? Or how how many WAC
Corporals had a recovery system failure? It's all here.
Peter has also gone to the trouble of converting the thrust of all
the rockets to consistent units (newtons). In addition he's listed
the performance of each rocket in model rocket terms. If you've ever
wondered how many Estes Saturn V's you need to equal the real thing ;-)
Go lurking on rec.models.rockets. Peter is on the net and a regular
contrbutor there. They'll be able to tell you how to get the book.
No space fan should be without a copy! In fact, it may be a good
text book for your course.
... G**2
In article <[email protected]>, [email protected] (Richard
D Pierce) writes:
|> For a class I am teaching, we are looking at some representative
|> performance parameters for US launch vehicles. I am looking for some of
|> the basic operating parameters of some of the more common ones, such as
|> Atlas, Atlas/Centaur, Mercury/Atlas, Titan II/Gemini, Titan III, etc.
|> Delta, Saturn I, Saturn V, Shuttle and so on. Also, if available, data on
|> Soviet/Russian, Arianne and others would be good, too.
|>
|> [Mod note: much of this is in the sci.space Frequently Asked Questions
|> list... not all, though -gwh]
|>
|> I am looking for enough information to run credible simulations of launch
|> profiles (we're trying to see just how hard it is to get into orbit). The
|> kinds of information I am looking for include:
|>
|> Vehicle weight (empty, per stage)
|> Fuel load
|> Isp
|> Liftoff thrust/vacuum thrust
|> payload weight
|> Effective flat plate area
|> Maximum G-load limits (structural, payload)
|> Maximum aerodynamic loads
|>
|> I've constructed a little "engine" that one can plug numbers into and get
|> a ballpark profile of a launch.
|>
|> If anyone can supply this data or point me in the right direction, I
|> would appreciate it.
|>
|> --
|> | Dick Pierce |
|> | Loudspeaker and Software Consulting |
|> | 17 Sartelle Street Pepperell, MA 01463 |
|> | (508) 433-9183 (Voice and FAX) |
|
| 33.9 | FAQ Table of Contents | VERGA::KLAES | Quo vadimus? | Wed Mar 02 1994 12:34 | 284 |
| Article: 15948
Newsgroups: rec.models.rockets
From: [email protected] (Buzz McDermott)
Subject: FAQ: Table of Contents
Organization: NETCOM On-line Communication Services (408 241-9760 guest)
Date: Wed, 2 Mar 1994 04:30:09 GMT
Last Modified: 1 March 1994
REC.MODELS.ROCKETS FREQUENTLY ASKED QUESTIONS
TABLE OF CONTENTS
New for Mar 94:
- Updated regulatory comments and remarks in Parts 1,2 and 3
- Updated several glossary entries Part 1
- Corrected names and addresses in Part 1
- Corrected more typos in all Parts
- Part 4 has been updated (see separate summary of changes in Part 4)
Comming in Apr 94 Posting:
- Expanded information on using reloadable motor technology
- Expanded scale information
- New section on 'Cheap Rocketry' for the budget-minded rocketeer
PART 1: GENERAL INFORMATION
1.1 Abbreviated Glossary
1.2 Rules, Regulations, and Government Speak
1.2.1 NFPA, FAA, DOT, ... Who are all these organizations and
how do they affect the rocketry hobby?
1.2.2 What are some of the pertinent regulations that affect
rocketry, both model and high power?
1.2.3 Okay, so how do things stand today? What is and isn't legal?
1.3 Some Commonly Sought Addresses
1.3.1 What national-level consumer rocketry organizations exist?
1.3.2 What are the addresses of some the rocketry manufacturers? Do
they offer catalogs?
1.3.3 What about addresses where I can get electronic timers,
stagers, video and other advanced payloads?
1.3.4 Are there other sources of kits, motors, parts and supplies
I should know about?
1.3.5 Could you please summarize published electronic mail
addresses for rocketry manufacturers and individuals?
1.4 Other Sources of Information
1.4.1 What are some good books to read to learn more about model
and high power rocketry?
1.4.2 Are there any rocketry magazines available?
1.4.3 Are there any other on-line sources of rocketry related
information, especially model and high power rocketry
related?
1.4.4 How do I access the r.m.r archive? How do I submit files to the
archive?
1.4.5 Are there any other on-line discussion groups relevant to
model and high power rocketry?
PART 2: MODEL ROCKETRY
2.1 Model Rocketry Questions
2.1.1 Is the proper term rocket 'engine' or rocket 'motor'?
2.1.2 Are there any local or national organizations to which I
could or should belong?
2.1.3 What do the letters and numbers on a model rocket motor mean?
2.1.4 Can I legally fly model rockets in my state? What are the
restrictions?
2.1.5 I have a son/daughter that is (6 - 9) years old. Is this
too young for model rocketry? If not, are there any tips
for helping to keep their interest in the hobby?
2.1.6 Is there any way I can buy model rocket kits, parts and
engines at less than full retail?
2.1.7 I've had a large number of motors CATO recently. The engines
are only about 2 years old. I've had them stored in my
(attic/garage/basement).
2.1.8 Is it safe to use my old rocket engines from <nn> years ago?
2.1.9 What's a good way to find other rocket enthusiasts in my
area? How can I found out about local rocket clubs?
2.1.10 Are the Aerotech composite motors the same size as Estes/
MRC/Quest motors?
2.1.11 Can I use Aerotech or other composite motors in my Estes
rockets?
2.1.12 I've seen mention of a new E motor coming from Estes. Is it
the same as the Aerotech E motors?
2.1.13 Will my Estes launch system work with Aerotech composite
motors.
2.1.14 Can I use Aerotech composite motors as boosters in my multi-
stage rockets?
2.1.15 How can I tell the age of my Estes motors?
2.1.16 I've heard about reloadable motor technology for model rocket sized
motors. I've also heard they have been banned. What is their
current status?
2.1.17 My flying field is so small I keep losing my rockets. What can I do?
2.1.18 Are Jetex engines still made? Where can I find them?
2.2 Born-Again Rocketeers
2.2.1 Who's Left, Who's Not & Who's New
2.2.2 Changes in Motor Technology
2.2.3 High Power Rocketry
2.2.4 Electronics Advancements
2.2.5 Regulations, Regulations, Regulations
2.3 Construction and Finishing Tips
2.3.1 Cutting, Sealing, Attaching Fins
2.3.2 Body Tubes (Cutting, Joining, Filling)
2.3.3 Parachutes
2.3.4 Ignition and Launching Tips
2.3.5 Alternatives to Recovery Wadding
2.3.6 Nose Cones
PART 3: HIGH POWER ROCKETRY
3.1 On To High Power
3.1.1 I'm a successful model rocketeer. What do I need to get into
HPR?
3.1.2 What are the major differences between model and high power
rockets, besides size and engines? Are they built differently?
3.1.3 Are there any national organizations to which I could join?
3.1.4 What is a 'reloadable' motor. Are they worth the price? Are
they legal?
3.1.5 What is the current legal status of HPR motors? I've heard the
DOT has banned them. Is that true?
3.1.6 What are these different 'types' of composite motors I hear
about (White Lightning, Black Jack, Smokey Sam, etc.)?
3.1.7 What's an FAA waiver? Which rocket flights require one?
3.1.8 Is high power rocketry legal in every state, if the proper
forms are obtained?
3.1.9 I've heard that NAR and Tripoli both have a certification
process for using/launching HPR. How do I get certified? Am I
required to be certified if I want to fly HPR?
3.1.10 Where do I find out the proper way to use HPR rockets and
motors? I'm familiar with the NAR Model Rocketry Sporting Code.
Is there an HPR equivalent?
3.1.11 What are some good kits to build when first getting into high
power rocketry (assuming I have all of the basic model rocketry
skills)?
3.2 Construction and Finishing Tips
3.2.1 Cutting, Sealing, Attaching Fins
3.2.2 High Power Motor Hooks
3.2.3 Custom Decals for High Power Rockets
3.2.4 Getting Paint to Stick to LOC and Aerotech Nose Cones
3.2.5 Preventing 'zippered' body tubes
3.3 Ignition and Launch Systems Tips
3.3.1 Copperhead, squibb, electric match, thermalite, flash bulb. What are
all these types of igniters, how much current do they require, and
when are they used?
3.3.2 How do those 'Copperhead' igniters work? They only have one
wire?
3.3.3 Do you have any specific suggestions or tips for an ignition
power sources? Can I use my old Estes ignition system with
composite models?
3.3.4 WARNING: BE VERY CAREFUL USING ANY IGNITION SYSTEM WITH
'FLASHBULB' TYPE IGNITERS.
3.3.5 THE IGNITION OF ROCKETS BY OTHER THAN ELECTRICAL MEANS IS BANNED
BY BOTH THE NAR AND TRIPOLI SAFETY CODES AND SHOULD NOT BE USED.
3.3.6 What is thermalite fuse and how is it involved in igniting
rocket motors?
3.3.7 How do you ignite second stage composite motors? Can I use a
black powder booster for the first stage to ignite the second
(as I do with my Estes rockets)?
3.3.8 Other Ignition Tips...
3.4 Large Rocket Glider Construction Tips
3.4.1 Construction Reviews
3.4.2 I'm building the 'XXX' R/C Rocket Glider and it uses foam core
wings. Are there any things I should know about working with
foam?
3.4.3 Any tips for sheeting the wings on my Aerotech Phoenix?
3.4.4 How about help with my Estes Astroblaster wings?
3.4.5 How do you repair damaged foam wings?
3.4.6 Some more uses of foam in rocketry...
3.4.7 I need to cut the piano wire control rods. Bolt cutters don't
work well, as the metal is too hard. Any ideas?
PART 4: PAYLOADS
4.1 Camera Payloads
4.1.1 Commercial Cameras
GENERAL TIPS
SOME THOUGHTS ON FILM
ENGINE COMBOS
REVERSING THE CAMERA
CLEANING THE CAMERA
GETTING THE PHOTOS PRINTED "RIGHT"
4.1.2 Homebrew cameras
Still Cameras
Movie Cameras
4.1.3 Video
4.2 Data Gathering Payloads
4.2.1 Transmitter
4.2.2 Data logging
4.2.3 Sample collection
4.3 Bio-payloads
4.4 Guidance Systems
4.5 Novelty Payloads
4.5.1 Contest payloads
4.5.2 Ejecting payloads
PART 5: SCALE MODELING AND COMPETITION
5.1 Scale Modeling
5.1.1 I would like to make a scale model of the <??> rocket.
Where do I start looking for technical data, dimensions,
flight substantiation data, etc.?
5.1.2 I've never built any scale models. Are there any
recommended kits for first timers?
5.1.3 O.K., I've done all my research, collected all the data I
can. I've even built a couple of scale kits a a warm up.
Now I'm ready to build a model I can be proud of.
How do I...?
5.1.4 What tools do I need?
5.1.5 Where can I get more information on modeling techniques?
5.2 Summary of Events and How to Get Started
5.2.1 I would like to get into competition. I would prefer to start
with kits rather than designing and building my own. Are there
any manufacturers making kits specifically designed for
competition?
5.2.2 What are the major categories of competition model rocketry?
5.3 Competition Tips and Strategies
5.3.1 What are some good events to try when first getting into
competition? Any 'sage' advice?
5.4 Some Model and High Power Rocketry Records
5.4.1 High Power Altitude Records
5.4.2 Biggest Non-metallic Rockets
5.4.3 Other Non-professional Flights of Note
5.4.4 Some Model Rocketry Records
INTRODUCTION TO REC.MODELS.ROCKETS AND THIS FAQ
Rec.models.rockets (r.m.r) is a Usenet newsgroup oriented towards
discussions and topics related to non-professional rocketry of all
types. All questions, comments, and ongoing discussions related to
non-professional rocketry are welcome.
This FAQ (list of Frequently Asked Questions) is an attempt to
compile a number of questions and suggestions that have been repeatedly
posted to r.m.r into a single, quickly readable document. This
document is NOT a 'how to' on any form of non-professional rocketry.
It's hoped that it might be of use in answering some of the more
commonly asked questions, summarizing some good tips and suggestions,
and directing the reader to other documents, books, sources, etc.,
where more information may be found. It is organized as a list of primary
topics (see the Table of Contents) with a number of questions and answers
under each. The majority of this document deals with, but is not limited
to, consumer rocketry in the United States and Canada.
This document was originally compiled (with much help from many others) by
Buzz McDermott and Jack Hagerty.. They would like to thank all those who
contributed and helped with this FAQ. Jack is the editor of Part 4, Payloads.
Comments, corrections, suggestions for improvements and new ideas for this
FAQ may be mailed to [email protected] or [email protected]. All comments,
suggestions and corrections are welcome and encouraged.
Many of the rocket manufacturer and mail order house addresses in this
document were originally obtained from the 'List of rocket manufacturers
and organizations (Updated Oct 1992)', maintained by R. M. Jungclas.
***** PLEASE READ THIS *****
Many of the tip and suggestions included in this FAQ include references to
particular companies and/or products. Opinions expressed are those of the
submitters. Several submitters have asked that readers do not request
the company names and addresses from them. Please refer to the addresses
section of the FAQ, R.M. Jungclas' list of addresses, or a recent issue of
one of the rocketry magazines. You may also post an address request to
r.m.r., but be forewarned that you may get chastised if you've failed to
read the FAQ or one of the other sources of addresses, first.
Most of the submitters are happy to answer questions about their ideas and
suggestions, but PLEASE don't ask them for names and addresses of suppliers.
Check this FAQ and the manufacturers list maintained on the sunsite archive
first.
|
| 33.10 | FAQ Part 1 of 5 | VERGA::KLAES | Quo vadimus? | Wed Mar 02 1994 12:34 | 966 |
| Article: 15949
Newsgroups: rec.models.rockets
From: [email protected] (Buzz McDermott)
Subject: Frequently Asked Questions - Part 1 of 5
Organization: NETCOM On-line Communication Services (408 241-9760 guest)
Date: Wed, 2 Mar 1994 04:31:10 GMT
Rec.Models.Rockets FAQ (Frequently Asked Questions): Part 1 of 5
Last Modified: 1 March 1994
This FAQ will be posted approximately once a month.
*** PART 1: GENERAL INFORMATION
Section 1.1: Abbreviated Glossary
The following are some commonly used abbreviations, terms, and acronyms used
within r.m.r. These definitions have come from many contributors. Thanks to
all for their help in building this glossary. A more complete glossary is
maintained by Jack Hagerty ([email protected]). Check out the r.m.r archive. See
'Other Sources of Information', below, for details.
advanced see 'high power rocket'
rocket
AmSpac Abbreviations for "American Spacemodeling", the journal of
AmSpam the National Association of Rocketry. Published until August
1993. See "Sport Rocketry".
amateur The class of non-professional rocket beyond HPR. Amateur
rocket rockets may use structural metal parts and very often the motor
or casing doubles as the airframe (as with professional rockets).
experimental These rockets can be very large and powerful, capable of placing
rocket payloads many miles up. Activities in this field (one can
scarcely call it a hobby) include formulation and manufacture
of propellants and thus can be EXTREMELY hazardous. This is
the main reason that amateur rocketry is not to be attempted
alone. Another is expense as these vehicles can run many hundreds
or thousands of dollars and take months to build. The equipment
necessary to safely pursue amateur rocketry (sandbagged bunkers,
loading pits, standby fire truck, etc.) are quite beyond the
resources of individuals.
Not all amateur rockets are so large. Many of the "beginner"
vehicles would qualify as HPR or even model rockets in terms
of liftoff weight and total impulse, but fail the NAR/Tripoli
codes due to their metal airframes and/or user-compounded propel-
lants. Note: There is a fine, but significant, difference
between using a metal cased reloadable motor with
pre-manufactured fuel slugs and stuffing a pipe with
zinc/sulfur (a common amateur beginner fuel).
Liquid fueled vehicles are becoming more popular among amateur
groups. These can produce up to 1,000 lbs of thrust for up to
a minute from a LOX/Kerosene engine which can propel the vehicle
to altitudes of over 40 miles. Some hobby!
BAR Born Again Rocketeer. An individual who has rediscovered the
hobby/sport after an absence of several years.
black powder Basically, gunpowder. The 'traditional' model rocket motor
fuel. Used by Estes, Quest, FSI, and most other model rocket
motor through D power. There are black powder motors available
through H power.
CA Cyanoacrylate ('super glue'). A very strong adhesive popular
cyano for use in competition and high power rockets, as well as
'on the field' repairs. The three most common forms of CA are
often referred to as 'hot', 'gap filling' and 'slow'. Hot CA
is very thin and has strong wicking properties. It dries in
only a few seconds. Gap filling CA is a little thicker and
generally comes in 15 - 30 second bond times. Slow CA forms
the strongest bond but its bond times are also much longer.
Hot or gap filling CA is often used to tack parts into place
prior to applying a stronger adhesive with a much longer
bonding time (such as an epoxy).
CATO a motor failure, generally explosive, where all the
propellant is burned in a much shorter time than planned.
This can be a nozzle blow-out (loud, but basically harmless),
an end-cap blow-out (where all of the pyrotechnic force
blows *forward* which usually does a pretty good job of
removing any internal structure including the recovery
system) and finally, a casing rupture which has
unpredictable, but usually devastating, effects. Another
form of CATO is when there is a motor delay train or
ejection failure. This may be caused by either the delay
train failing to burn or the ejection charge not firing, but
the result is the same: the model prangs.
Refer to the full r.m.r Glossary for history of the term.
CG Center of Gravity. The point about which a free body will rotate
when disturbed by an outside force. For a model rocket, this is
the point where the masses of the individual components equal
out and the model will balance on a knife edge. As with a see-
saw, a mass further from the CG will have a greater effect than
the same mass closer in.
composite The term used broadly to cover solid fuel rocket motor
using other than black powder. Composite motors require
different igniters and igniter systems from black powder
motors.
CP Center of (Aerodynamic) Pressure. The point on a rocket
where stability-restoring forces due to airflow against the
back part of the rocket (fins, etc.) exactly equal the
disturbing forces due to airflow against the part of the
rocket ahead of that point.
The location of this point depends on how much the rocket's
orientation is disturbed at the time of measurement. If it
is at a very small angle to the "local wind" (line of flight),
the fins' restoring contribution will be large, while the
nose's disturbing contribution will be small, resulting in a
CP that is way back. The CP in this case can be located using
the Barrowman Equations. If the rocket is nearly sideways,
the CP will be much more forward. The CP in this case can be
located by balancing a cardboard silhouette of the rocket.
Since all free bodies will rotate only on their center of mass,
stability is usually a simple matter of ensuring that your CG
is ahead of your CP, which ensures that the restoring forces
of airflow on the rear of the model will always overcome the
disturbing forces on the front.
A good rule of thumb for sport models (both high and low power)
is to design the rocket with the CP one or two body diameters
behind the CG.
engine A machine that converts energy into mechanical motion. Such
a machine distinguished from an electric, spring-driven or
hydraulic motor by its consumption of a fuel (from _American
Heritage Dictionary_).
FIREBALLS An annual experimental rocketry/HPR launch put on by AERO-PAC
(see "experimental rocket") where emphasis is on VERY LARGE
advanced rockets of "K" impulse or higher. Developed by Bill
Lewis and Steve Buck the name came from jokes surrounding the
event (e.g. "Those are Big Ass Load Lifting Suckers" and "It
takes BALLS to launch a rocket that big").
Since Fireballs has been traditionally held on the Monday
following LDRS (q.v.), many people think that Fireballs is
a Tripoli launch. While 1992's Fireballs (where 'Down Right
Ignorant' was launched) was sponsored by Tripoli for the
purposes of insurance coverage, it is not a sanctioned Tripoli
event.
high power a non-professional rocket weighing more than 1500 grams
rocket at liftoff, containing more than 125 grams of propellant,
or or containing any motor with more than 62.5 grams of propellant,
advanced or having a liftoff weight greater than 1500 grams (3.3 pounds).
rocket High power motors go all the way to class 'O',
with over 40,000NS of total impulse. High power rockets
require an FAA waiver to launch.
high power a term sometimes used to describe rockets using motors in the
lite 'E', 'F', and 'G' power classes. It is also used to
sometimes describe rockets which fall between the old
NFPA weight limit of 1 pound (~454 grams) and the new
NFPA-1987 model rocket weight limit of 1500 grams. Rockets in
the 'E' through 'G' class aren't normally considered advanced,
high power rockets but are often built using many of the same
construction techniques as the larger rockets.
HPR High Power [Rocket(ry)]. See 'high power rocket'.
HPR 'High Power Rocketry Magazine', formerly 'Tripolitan...
Magazine America's High Power Rocketry Magazine'. An independent
(HPRM) magazine dealing with all aspects of consumer rocketry,
but with a definite emphasis on high power, advanced and
experimental consumer rocketry.
LDRS The annual national high power sport launch sanctioned by
Tripoli. LDRS stands for "Large Dangerous Rocket Ships," the
derivation of which is best left to others. Note: LDRS has NEVER
stood for "Lets Do Rocketry Safely", despite what you hear from
historical revisionists trying to mollify public officials :-)
model rocket An aero-vehicle that ascends into the air without the use of
aerodynamic lifting surfaces. The gross launch weight,
including motor(s), will not exceed 1500 grams. Motor(s) for
said vehicle will not exceed 160 Newton seconds of impulse and/
or contain more than 62.5 grams of propellant each, and no more
than a total of 125 grams of propellant in multiple motor
situations. All components of said vehicle will be of wood
paper, rubber, breakable plastic or similar material and
without substantial metal parts.
Note: Model rockets in Canada are limited to 1 pound total
launch weight and 80NS of total impulse. The same
rules apply for construction materials as with US NFPA
guidelines.
modroc Model Rocket. Also seen as 'modrocer', or similar spelling,
to mean 'model rocketry enthusiast'.
motor Something that imparts or produces motion, such as a machine
or engine. A device that converts any form of energy into
mechanical energy (from _American Heritage Dictionary_).
NAR National Association of Rocketry. A national hobby organization
promoting model and high power rocketry in the United States.
The NAR promotes rocketry related sport flying, competitions,
and education. See 'Often Sought Addresses'.
NARAM National Association of Rocketry Annual Meet. The NAR
national championships competition, held in August of
each year.
NARCON National Association of Rocketry Annual Convention. An annual
event sanctioned by the NAR oriented towards non-competitive
(i.e., sport) model and high power rocketry. It includes
seminars, R&D presentations and lots of sport flying.
NARTS National Association of Rocketry Technical Services. See
section 5 for address.
Newton & Metric units used to measure thrust and total impulse,
Newton-second respectively, of NAR and Tripoli certified rocket motors.
(NS) One pound = 4.45 newtons.
NSL National Sport Launch. An annual, national sport fly. One of
two national events sponsored by the NAR. It has been held
both immediately preceding the NARAM national competition
as well as mid-point in the year between NARAMs (Feb).
PMC Plastic Model Conversion. The term used to describe a plastic,
static model of some type (typically an aircraft, rocket or
spaceship) that has been converted to fly as a model or
high power rocket. This term is also used as an abbreviation
for an NAR-sanctioned competition utilizing converted models.
R/G Rocket glider. A glider which is boosted to altitude by a
rocket. The entire model glides down together. No part of the
model separates, as in a boost glider. Technically, an R/G is
a particular form of B/G.
RMS(TM) Reloadable Motor System. The trademarked name of the Aerotech/
ISP reloadable motors. Often used (incorrectly) as a generic
name for all reloadable technology.
Sport Rocketry The official journal of the National Association of Rocketry
Magazine as of the September/October 1993 issue. The magazine covers
(SRM) NAR activities, model rocketry and high power rocketry.
Through The An HPR fin attachment technique which provides much greater
Wall (TTW) strength than the typical surface mount used in model rocketry.
To use TTW, slots are cut in the body tube where the fins mount
and the fins are built with extended tabs on the root edge which
fit through these slots. In one form of TTW, the tabs are
short and just provide a surface to build up epoxy fillets on
the inside as well as the outside. In a stronger version of TTW,
the tabs reach all the way to the motor tube where they are
glued forming a very rigid box structure.
Tripoli Tripoli Rocketry Association. A consumer rocketry organization
(TRA) founded to promote the interests of high power and advanced
rocketry enthusiasts. See section 5.1 for address.
Tripolitan "The Tripolitan...America's High Power Rocketry Magazine".
The bi-monthly journal of the Tripoli Rocketry Association,
published until July/August 1992. See 'HPR Magazine'.
waiver The term used to describe the official permission given by
the FAA allowing rockets with more than 4 ounces of fuel or
weighing more than 1 pound to be flown into FAA controlled
airspace. See section 3.1.7 for more details.
details on FAA waivers.
YABAR Yet Another Born Again Rocketeer. See BAR.
Again, check or Jack's glossary of consumer rocketry terms for a much more
Complete listing.
Section 1.2: Rules, Regulations and Some Government-Speak
Consumer rocketry is being assaulted from all directions by multiple
government agencies. The NAR and Tripoli must become increasingly aware
of the areas of responsibility of these agencies (which sometimes overlap)
and how they might affect rocketry.
This section briefly describes some of the government regulations under which
model and high power rocketry are practiced. It also provides a VERY brief
summary of the current regulatory status of our hobby. Don't take what is
printed here as law. This is only the FAQ editor's (often misguided :-)
understanding of current regulations. If there are conflicting statements
elsewhere in the FAQ this section is meant to be the 'authority', such as it is.
1.2.1 NFPA, FAA, DOT, ... Who are all these organizations and how do they
affect the rocketry hobby?
DOT (Dept. of Transportation) regulates shipping of rocket motors and
reloads.
CPSC (Consumer Protection Safety Council) regulates what may and not
be sold as a 'consumer' items at the retail level.
FAA (Federal Aviation Administration) is responsible for airspace
control and regulates flights of rockets that exceed 1 pound and
enter FAA regulated airspace.
NFPA (National Fire Protection Association) makes recommendations for
use of non-professional rocket motors. Although the NFPA only
makes recommendations, most state and local laws concerning the
use of model rockets are based, in part, on NFPA recommendations;
especially NFPA 1122.
BATF (Bureau of Alcohol, Tobacco and Firearms) has responsibility for
regulations concerning storage and use of explosives. This agency
has taken a recent interest in looking into how high power rocket
motors are stored and used.
1.2.2 What are some of the pertinent regulations that affect rocketry, both
model and high power?
FAR 101 The section of the FAA code for which a waiver must be applied
when desiring to fly rockets weighing in excess of 1 pound.
The NAR is working with the FAA to try and get these regulations
changed to allow all MODEL rockets up to 3.3 pounds in launch
weight to be excluded from the waiver requirement.
NFPA 1122 The current NFPA recommendations concerning model rockets. The
last adopted recommendations were enacted in 1987 and defined a
model rocket as being less than 3.3 pounds in launch weight,
containing less than 125 grams of fuel, with no motor containing
more than 62.5 grams of fuel. Since the current guidelines were
written in 1987 the recommendations are sometimes written as NFPA
1122-1987. The NAR is currently working to get reloadable
motors with less than 62.5 grams of fuel to be included as
model rocket motors. The current NAR Model Rocket Sporting Code
is based on NFPA 1122. AS IT CURRENTLY STANDS, NO RELOADABLE
MOTOR, NO MATTER HOW SMALL, IS A 'MODEL ROCKET' MOTOR. The NFPA
is ready to accept metallic reloadable motors as soon as federal
agencies such as the CPSC are ready to.
NFPA 1127 Proposed NFPA recommendations for flying high power rockets.
The NAR and Tripoli are working to get this set of guidelines
adopted. These would cover rockets of over 1500 grams launch
weight and/or containing at least one motor with more than 62.5
grams of propellant and/or containing motors with total
propellant exceeding 125 grams.
16 CFR Code of Federal Regulations. The CPSC currently has rocket
1500,85 motors of greater than 80NS total impulse listed as high
(a)(8) power motors under 16 CFR 1500,85(a)(8)(ii). The NAR is
(iii) currently working on convincing the CPSC to change the
regulations to allow G motors as model rocket motors. Aerotech
G motors are currently obtainable due to a stay of enforcement
granted to Aerotech by the CPSC.
?????? The Department of Transportation regulations dealing with the
(cite shipment of model and high power rocket motors. Model rocket
unknown) motors ship as Class C Toy Propellant Devices. High Power
motors ship as Class B Explosives. High Power reloads are
currently banned from interstate shipping and commerce as
'hazardous' materials. Model rocket motor reloads (i.e., G
reloads and under) were banned as well, but the DOT reclassified
Aerotech B-G reloads as Class C in May, 1993. The NAR and
Tripoli are working to get the status of high power reloadable
motor components changed so that we may once again enjoy the
benefits that reloadable technology has brought to this hobby.
1.2.3 Okay, so how do things stand today? What is and isn't legal?
1. Model rockets may now be up to 3.3 pounds in weight and contain up to
125 grams of fuel with no motor containing more than 62.5 grams of fuel.
You can fly models this big without having any sort of high power
certification. Two composite G motors (such as Aerotech G40 or G80) or
3 composite F motors (such as Aerotech F25 or F50) could be used in a
cluster or staged model and still be classified a model rocket by the
NFPA 1122 and NAR safety code definitions. This is from the NFPA
guidelines and NAR model rocket safety code.
2. The FAA requires a waiver to the regulations in FAR 101, however, in
order to legally fly any rocket (model or high power) which weighs over
one pound gross launch weight (i.e., motor(s), recovery system, and all).
This means that several of the Aerotech models, and most of the LOC and
NCR models, along with the some Estes Pro series rockets, require an FAA
waiver to fly. Remember that an FAA waiver and high power certification
are different issues.
3. Aerotech high 29mm and 38mm high power reloads (the ones sold under the
'ISP' or 'Aerotech High Power' labels) may be shipped to certified
flyers, except for the 38mm Black Jack reloads. Shipment is by UPS as
Flammable Solids. If you ship your 54 or 98mm casings to Aerotech,
they can partially load them with a single reload and return ship the
loaded casing as a Class B Explosive (FedEx counter to counter, $50
shipping cost).
4. The Aerotech 18-29mm 120NS and under reloads may again be sold at
retail. However, the NAR and Tripoli both now have policies in place
that only motors certified by one or both of the organizations may be
used at launches sanctioned by either organization. At present, not
all of the reloads are certified. Remember that only certified motors
are allowed at NAR and TRA launches. Check the certification lists in
the r.m.r archives on sunsite.unc.edu or the periodic postings in Sport
Rocketry and High Power magazines. Also, these reloads may only be sold
to buyers 18 years of age or older, to comply with CPSC restrictions.
5. G class model rocket motors (80.01-160.00NS total impulse) have been
classified as high power by the CPSC. They are considered model rocket
motors by the NFPA. To avoid these motors being banned from retail sale
by the CPSC, these motors are now restricted for sale to buyers 18 years
of age or older. This includes the sale of G reloadable motors.
6. The NAR and Tripoli both have programs for obtaining high power
certification. You need to join one or both of these organizations if
you want to fly high power rockets.
7. Disposable high power motors have not changed status and are still
classified as Class B explosive devices. Properly certified individuals
may purchase these motors via mail order, but there are severe shipping
restrictions.
8. The new designation for Class C motors is now 'UN 1.4c'. The new
designation for high power motors, Class B, is now 'UN 1.3c'.
9. Aerotech reloads of sizes greater than 38mm (i.e., 54 and 98 mm reloads)
may be shipped as Class B explosives (such as disposable HPR motors),
BUT ONLY if the propellant slugs are assembled into and shipped with
the appropriate reload casing. In other words, you have to ship your
54 or 98 mm hardware set to Aerotech to order a single reload for that
hardware set.
---------------------------------------
Section 1.3: Some Commonly Sought Addresses
NOTE: The following addresses are being supplied because they have been
referenced in multiple postings to r.m.r. Their inclusion here is not
an endorsement of any particular product or organization.
This list is not complete. These are just a few of the many suppliers
of model rocket kits, supplies, components and motors. Refer to the
list of suppliers maintained by R.M. Jungclas for a more complete
set (see Section 1.4.3).
1.3.1 What national-level consumer rocketry organizations exist?
Canadian Association of Rocketry Model rocketry organization
P.O. Box 1031 for Canadian aerospace
Postal Station "B" modelers
Mississauga, Ontario
L4Y 3W3
(416) 272-4622
National Association of Rocketry Model and high power rocketry
P.O. Box 177 for aerospace modelers in
Altoona, WI 54270 U.S.
(715) 834-8074 - sanctions contests
(800) 262-4872 - NARAM and NSL yearly national
Email: [email protected] competition and sport launches
- model and high power motor
certification
- Insurance for rocket flying
activities (model and high
power): $21/year for $1M
liability insurance coverage
- Sport Rocketry magazine
- High power certification
- Motor certification (model and
high power rocket motors)
- Dues: $35/year (senior;
includes Sport Rocketry
subscription); $20/year for
those under 18; add $14.75/
year for First Class postage
- High power certification
- NARTREK continuing education
program
Tripoli Rocketry Association, Inc. High power rocketry enthusiasts
P.O. Box 339 - Sanctions & insures high power
Kenner, LA 70063-0339 rocket launches
- High power certification
- Dues: $47/year (includes sub-
scription to HPR
magazine)
$25/year (with no
magazine)
$60/year (with magazine
sent first class)
- High Power Rocketry magazine
(optional, see above)
- Yearly national sport launch
(LDRS)
1.3.2 What are the addresses of some the rocketry manufacturers? Do
they offer catalogs? Refer to Part 2 for information on model
rocketry and Part 3 for information on high power rocketry.
AAA Model Aviation Fuels Large Model Rocket Kits
Large Scale Rocketry Division High Power Kits
122 Summer Ave. Distributor - motors and part
Clarks Summit, PA 18411 Catalog: $2
Aerotech, Inc. Composite motors, reloadables
1955 South Palm St., Suite 15 (B - M)
Las Vegas, NV 89104 Large model rocket kits; high
(702) 641-2301 or 2302 power rockets, part, supplies.
Catalog: $2
Aerotech High Power Class B motors and high power
1955 South Palm St., Suite 15 reloads and hardware (G -
Las Vegas, NV 89104 M).
(702) 641-2301 or 2302 Motor Literature: $5
Cluster R High power rocket kits, parts
c/o Larry Russell
604 Lakeview Drive
East Peoria, IL 61611
(309) 698-0726
Custom Rockets A-D powered model rocket kits
P.O. Box 2086 and parts.
Augusta, ME 04338-2086
(800) 394-4114
(207) 623-4114
Dangerous Dave's Products See 'MRED Industries' entry
Dynacom Composite Dynamics, Inc. High power rockets (fiberglass
P.O. Box 85 and composite components).
Boston, PA 15135 Catalog: $3
(412) 751-9515
Energon Motors See 'MRED Industries' entry
Estes Industries 1/2A - E kits; 1/2A - E motors.
P.O. Box 227 Model rocket parts, supplies.
Penrose, CO 81240 Catalog: $1
(719 )372-6565
(719 )372-3419 (fax)
(800) 525-7561 (toll free)
LOC/Precision Large model rocket kits; high
1042 Iroquois power rocket kits; Rocket
Macedonia, Ohio 44056 parts and supplies;
(216) 467-4514 Catalog: $2
Microbrick Technologies, Inc. See 'MRED Industries' entry
Model Rectifier Corporation A-D model rocket kits & motors
2500 Woodbridge Ave. Catalog: ??
Edison, New Jersey 08817
North Coast Rocketry Manufacturer of model and HPR
4848 South Highland Drive, Suite #424 kits, parts, and supplies..
Salt Lake City, Utah 84117 F & G motors sometime late '93.
(800) 877-6032 (voice or fax) Catalog: $3
MRED Industries, Inc. Merger of Dangerous Dave,
P.O. Box 126 Microbrick, Energon and
Petersburg, NY 12138-0126 Rocketflite product lines.
(518) 658-9132 High power kits, parts,
motors (composite and black
powder), phenolic, G10 and
composite parts.
Catalog: $2
Public Missles, Ltd. High end model rockets and high
38300 Long power rocket kits, parts, and
Mt. Clemmens, MI 48045 parts
(313) 468-1748 Catalog: $3
Quest Aerospace Education, Inc. A-C model rocket kits & engines,
P.O. Box 42390 launch systems, and supplies
519 West Lone Cactus Drive Catalog: free
Phoenix, Arizona 85989-2390 NOTE: Quest has -2- catalogs,
(800) 858-7302 (toll free) one details retail kits in
(602) 582-3438 (voice) stores and the other one
(602) 582-3828 (fax) details "educational" mail
order sales from Quest
RocketFlite See 'MRED Industries' entry
Vaughn Brothers Rocketry Model and high power rocket kits
4575 Ross Drive kits and supplies; group launch
Paso Robles, CA 93446 systems
(805) 239-3818 Catalog: $1
(805) 239-0292 (fax)
Tiffany Hobbies of Ypsilanti (THOY) Large model and HPR rocket kits,
P. O. Box 467 parts and supplies.
Ypsilanti, Michigan 48197 Aerotech/ISP motor distributor.
(313) 741-0847 (voice or fax) Catalog: $2
U.S. Rockets Large model and high power rocket
P.O. Box 1242 kits, motors, parts and
Claremont, CA 91711 accessories
Catalog: free
Note: It has been reported in
rec.models.rockets that USR
has filed for bankruptcy.
Note: Be sure and specify that you want a manufacturer's model rocket or
high power catalog. Some manufacturers offer both.
1.3.3 What about addresses where I can get electronic timers, stagers,
video and other advanced payloads? Refer to Section 4 for information
on payloads.
Adept Electronics Electronic stagers, timers,
PO Box 846 altimeters, flight computers.
Broomfield, CO 80038-0846 Catalog: $2
MRED Industries, Inc. 4-event electronic timer
(See 1.3.2)
North Coast Rocketry Electronic timers and beepers
(See 1.3.2)
Supercircuits Electronic timers and beepers,
13015 Debarr Drive miniature cameras and
Austin, Texas 78729 transmitters
(512) 335-9777
(512) 335-1925 (fax)
Transolve Corporation Timers, altimeters, location
4060 E. 42nd Street beepers, etc.
Cleveland, Ohio 44105 Catalog: free
(216) 341-5970
1.3.4 Are there other sources of kits, motors, parts and supplies I should
know about?
There are a number of businesses that mail order rocketry-related
kits, parts, supplies, and motors. Some of these offer substantial
discounts from retail. The following companies are not the only
possibilities, nor are they necessarily the best or cheapest.
These are sources that have been positively mentioned in postings
in rec.models.rockets. For a more complete set of addresses refer
to R.M. Jungclas' list of manufacturers (posted to r.m.r on about
a quarterly basis).
Belleville Wholesale Hobby Estes, MRC, and Custom
1827 North Charles Street model rocket kits,
Belleville, IL 62221-4025 supplies, etc., at discount
(618) 234-5989 from retail.
(618) 234-9202 (fax) Catalog: $2
Countdown Hobbies Model and high power rocket kits,
3 P.T. Barnum Square parts. motors,, and supplies;
Bethel, CT 06801-1838 discontinued kits; space and
(203) 790-9010 (voice/fax) science items; collectors items
CompuServe: 74640,3112 Catalog: $2.50
Internet: [email protected]
High Sierra Rocketry High power kits, motors
P.O. Box 343 and supplies; also
Orem, UT 84059 Aerotech Class B & C
(801) 224-2276 composite motors.
Catalog: $1.00
Magnum Rockets, Hobbies and More, Inc. High power kits, motors
P.O. Box 124 and supplies; also
Mechanicsburg, Ohio 43044 Aerotech Class C
(513) 834-3306 (voice and fax) composite motors
Catalog: $2
Rocket Research & Distribution High power kits, motors
308 East Elm and supplies; also
Urbana, IL 61801 Aerotech Class C
(217) 344-2449 (voice) composite motors.
(217) 344-0327 (fax) Catalog: $2
1.3.5. Could you please summarize published electronic mail addresses for
rocketry manufacturers and individuals?
Some useful email addresses follow. They are all in Internet address
format.
NAR Headquarters [email protected]
NARTS, NAR Technical Services [email protected]
HPR Magazine (Bruce Kelly) [email protected]
Apogee Components (Ed LaCroix) [email protected]
Estes Industries (Michael Hellmund) [email protected]
North Coast Rocketry (Chris Pearson) [email protected]
MRED Industries (Michael Platt) [email protected]
Countdown Hobbies (Kevin Nolan) [email protected]
Jack Hagerty ([email protected]) has a much more complete list of email
addresses. This list is archived in the rmr directories on sunsite.unc.edu.
----------------------------------------
Section 1.4: Other Sources of Information
1.4.1 What are some good books to read to learn more about model and high power
rocketry?
Handbook of Model Rocketry, Fifth Edition (out of print)
G. Harry Stine
Synopsis:
THE handbook on model rocketry. Covers just about everything you need
to get started. Good tips for experienced modelers as well. Rumor has
it that a 6th edition is under preparation and looking for a publisher.
It is supposed to cover HPR.
Basics of Model Rocketry, 2nd edition
Douglas R. Pratt
Kalmbach Books, 1993
Synopsis:
A general introduction to model rocketry. The first edition is
available from NARTS for $6. Also sold at many hobby and craft stores.
The 2nd edition is highly revised and has become available as of Jan.
1993. The first edition is very Estes/Centuri/FSI oriented. The
second edition includes sections on composite motors, Aerotech, NCR
and other more recent manufacturers.
Advanced Model Rocketry
Michael A. Banks
Kalmbach Books, 1985
Synopsis:
A good introduction to E/F/G level rocketry. Some good construction
hints.
Building Plastic Models
Edited by Harold A. Edmonson
Kalmbach Books, eighth printing 1991
Synopsis:
Very helpful if you plan to do any PMC. Excellent sections on
painting, sanding, detailing models. Good discussion of modeling
tools.
Famous Spaceships of Fact and Fantasy (and How to Model Them)
Edited by Harold A. Edmonson
Kalmbach Books, 1979
Synopsis:
This book describes how several modelers built and modified some
plastic models of rockets from fact and fantasy. Great hints for PMC
detailing. Includes Saturn V, Enterprise (TOS), Gallactica fighters,
Star Wars Fighters, shuttle Aurora from 2001: A Space Odyssey, and
others.
The Model Rocketry Handbook
Stuart Lodge
Argus Books 1990
ISBN 1-85486-047-X
Synopsis:
British handbook on model rocketry. Geared towards beginners, but some
good tips for more experienced rocketeers. Available from NARTS for
$15.25 to NAR members. Soft cover, 128 pages.
Scale Model Rocketry, A Guide for the Historian-Craftsman
Peter Alway
Synopsis:
This was a limited-run, spiral-bound book that Peter published
himself. Those that have a copy say it is an excellent source of
scale data on a number of US rockets. It is out of production and
Peter has sold out. Go for his new book (see below).
Rockets of the World
Peter Alway
Synopsis:
The completely new replacement for his "Scale Model Rocketry...",
"Rockets of the World" is now ready. This is a must buy for any
scale modeling fans. This book contains information on more than 200
versions of 133 rockets from 14 countries and Europe. Available
via mail order fromn Saturn Press, NARTS, or Quest.
Hard cover:
$35.00 + $2.50 postage and handling.
Double-wire bound soft cover:
$28.00 + $2.50 postage and handling.
Foreign orders: $4.00 postage and handling.
Michigan orders add 4% sales tax
Send check or money order in US Funds to:
Saturn Press
P. O. Box 3709
Ann Arbor, MI 48106-3709
USA
Or order via MC/VISA at (313) 677-2321.
Estes Technical Reports
Estes has several introductory technical reports on rocket stability,
design, and other topics compiled into a publication called 'The
Classic Collection'. These technical reports were first published in
the 1960's. Estes also sells several other introductory books on
model rocketry.
NCR Technical Reports
North Coast Rocketry has a very extensive set of technical reports
dealing with advanced rocketry topics. These include clustering
(black powder and composite engines), staging composite motors,
adhesives, finishing techniques, launch systems, electronics,
supersonic rocketry and 'mile high' rocketry. A number of these
are available from NARTS. High power mail order shops often
stock these, as well.
NAR Technical Services (NARTS)
P.O. Box 1482
Saugus, MA 01906
Email: [email protected]
Synopsis:
Ok. This is not a book. It is a GREAT source of technical, scale,
and other information for NAR members. The 1992 catalog includes
books, technical reports (including some of the NCR series), and a
virtual plethora of goodies.
1.4.2 Are there any rocketry magazines available?
"Sport Rocketry"
Journal of the National Association of Rocketry
Published 6 times/year; subscription: $24/year (free w/NAR membership)
Subscription: Sport Rocketry
c/o National Association of Rocketry Headquarters
P.O. Box 177
Altoona, WI 54270
(800) 262-4872
"High Power Rocketry Magazine"
An independent consumer rocketry magazine. Formerly the journal of
the Tripoli Rocket Society.
Published 6 times/yr.; subscription $25/year (free w/Tripoli membership)
Subscription: High Power Rocketry
PO Box 96
Orem, Utah 84059-0096
"Liftoff Magazine"
P.O. Box 9331
Grand Rapids, MI 49509-0331
Subscription: $25/year (4 issues)
Synopsis:
Liftoff is a ~40-page DTP-produced quarterly journal dealing with the
history of space flight. It is published by Glen E. Swanson.
"Model Rocket News"
Estes Industries newsletter
Published twice or three times a year (Fall, Winter, Spring??).
Free to recent mail-order purchasers and Estes Space Club members
Subscription: ????
"Estes Educator News"
Estes Industries newsletter.
Synopsis:
A newsletter oriented to the needs of educators (teachers, rocketry
classes at YMCA/summer camps, etc.). Also useful for adult super-
visors in model rocketry clubs.
1.4.3 Are there any other on-line sources of rocketry related information,
especially model and high power rocketry related?
There are several lists of information maintained by readers of r.m.r.
You can email them directly to get the latest copy of each list.
These lists are also posted on a somewhat regular basis to this newsgroup.
Description
Rec.Models.Rockets Frequently Asked Questions (FAQ)
Maintained by: Buzz [email protected]
Synopsis:
A set of five text files plus a table of contents file. These make
up the FAQ which is posted to rec.models.rockets approximately once
per month.
List of Manufacturers, suppliers, mail order houses, etc., where
you can get rocketry and rocketry related engines, parts,
kits, data, etc. Very extensive.
Maintained by: R. Michael Jungclas
Email: [email protected]
From the introduction to the list:
Below is a list of current model rocket and high power manufacturers,
organizations and specialty companies. It is posted at irregular
intervals to r.m.r.
Note: Check the r.m.r archive at SunSite.UNC.EDU for this list.
List of sources for scale model data.
Maintained by: Kevin W. McKiou
Email: [email protected]
Synopsis: A compilation of sources to get information for scale modeling
projects. This list does not include any scale data in itself. It does
point to places to look for scale data. It is posted at irregular
intervals to r.m.r.
Note: Check the r.m.r archive at SunSite.UNC.EDU for this list.
Glossary of Model and High Power Rocketry Terms
Maintained by: Jack Hagerty
Email: [email protected]
Synopsis: An excellent assimilation of definitions for common, and
uncommon, terms and acronyms used in consumer rocketry. This list
is posted at irregular intervals to r.m.r.
Note: Check the r.m.r archive at SunSite.UNC.EDU for this list.
Model Rocketry Materials Density Table
Maintained by: Jack Hagerty
Email: [email protected] (Jack Hagerty)
From the introduction to the list:
The following is an informal (but hopefully fairly accurate) table of
the densities of common materials used in model rocket construction.
It is a running list meaning that new items will be added and existing
items will be updated as I use more of them. Many of the items are
commercially available, and for these I obtained values by measuring
the actual purchased items, not their catalog values.
Note: Check the r.m.r archive at SunSite.UNC.EDU for this list.
NAR/Tripoli Joint Summary of Certified Motors
Maintained by: Al Jackson
Email: [email protected]
Summary:
The joint list of all motors currently certified by either the NAR and/
or Tripoli Rocketry associations. NAR contest certified motors are
also noted.
Model rocketry archive at SunSite.UNC.EDU
Coordinated by: Robert B. Sisk
Email: [email protected]
Synopsis: This is the 'official' archive site for rocketry related
materials submitted by r.m.r contributors. The archive site has a number
of useful files. It contains rocketry related programs for IBM PC
compatible and Macintosh computers. Most of the regularly published
lists put out to r.m.r are also archived at this site. There are also
a number of rocket designs, graphics, and images. See the next section
for information on accessing this archive.
1.4.4 How do I access the r.m.r archive site? How do I submit files to be
archived?
To access the archive:
The r.m.r archive is available via anonymous FTP to SunSite.UNC.EDU.
Login as 'anonymous' and specify your email address as password.
Rocketry files are located in one of two places:
ftp/uploads/rockets (where files are initially uploaded)
pub/archives/rec.models.rockets (the final resting place for
archived files).
The archive system is a Sun system running SunOS version of Unix.
The procedure for submitting material is:
1) Ftp to sunsite.unc.edu and place the files to be archived into the
../ftp/uploads/rockets directory.
2) Send email to the r.m.r archive coordinator ([email protected].
Virginia.EDU) explaining what you have uploaded (file names, brief
description, etc.).
3) Post notice to r.m.r specifying what you have uploaded to the
archive.
The archive coordinator (Bob Sisk) will see to it that the files are
migrated from ftp/uploads/rockets to the pub/archives/rec.models.rockets
area.
1.4.5 Are there any other on-line discussion groups relevant to model and high
power rocketry?
There are several other newsgroups within Usenet that might be of interest
to readers of r.m.r.. These include:
- sci.aeronautics
- sci.astro
- sci.space.news
- sci.space.shuttle
None of the above are directly related to rocketry in any way. You can
often get information on scale model sources, history of particular
vehicles, etc., from the NASA and aeronautics industry people who read
these newsgroups.
There is a model rocketry discussion group on CompuServe. It is part of
the modelnet discussion groups. Type 'go modelnet' at any '!' prompt.
You must have a CompuServe account to access this list. The 'Sport
Rocketry' Special Interest Group (SIG) of modelnet is analogous to the
Usenet r.m.r group. Also, Internet users can mail CompuServe users if
the CompuServe id is known by using the address form:
[email protected], where the correct CompuServe account number
is substituted for "123456,1234" (note that a period separates the two
numbers rather than a comma).
If you are attempting to build or fly remote controlled B/G or R/G then
rec.models.rc might have some answers for you.
Finally, check with your local rocket club (NAR section, Tripoli prefect).
These groups often run local BBS (bulletin boards) for the benefit of
their members.
|
| 33.11 | FAQ Part 2 of 5 | VERGA::KLAES | Quo vadimus? | Wed Mar 02 1994 12:35 | 907 |
| Article: 15950
Newsgroups: rec.models.rockets
From: [email protected] (Buzz McDermott)
Subject: Frequently Asked Questions - Part 2 of 5
Organization: NETCOM On-line Communication Services (408 241-9760 guest)
Date: Wed, 2 Mar 1994 04:32:25 GMT
Rec.Models.Rockets FAQ (Frequently Asked Questions): Part 2 of 5
Last Modified: 1 March 1993
*** PART 2: MODEL ROCKETRY
Section 2.1: Model Rocketry Questions
2.1.1 Is the proper term rocket 'engine' or rocket 'motor'?
I don't know. I don't really care. And neither should you! In this
document 'motor' and 'engine' are taken to mean the same thing and both
refer to "the thing in the rocket which makes it go 'whoosh!!' (or 'roar',
if flying high power :-)". If you want a sure way to start a fight with
a fellow rocketeer, just argue that whatever term he/she uses is the wrong
one.
2.1.2 Are there any local or national organizations to which I could/should
belong?
There are two major national organizations serving the needs of non-
professional rocketry in the United States. The NAR is the largest and
oldest, having been formed over 30 years ago. The Tripoli Rocketry
Association was formed in 1985 specifically to serve the needs of the high
power rocketry community. See the section 'On to High Power' for details
on Tripoli. The addresses for both are in the section 'Some Commonly
Sought Addresses'. The address for the Canadian Association of Rocketry,
that country's equivalent to the NAR, may also be found in the addresses
section.
2.1.3 What do the letters and numbers on a model rocket motor mean?
The NAR has developed a motors classification scheme which has been
mandated by NFPA 1122 and most state regulations. This system
specifies the motors total impulse class, average thrust, and ejection
charge delay. This is printed on any motors certified by the NAR.
the pieces are as follows, given the example:
E15-10W
The 'E' stands for the total impulse class of the motor. This does not
mean that the motor has that much power. Motor classes indicate that a
a motor's total impulse falls within a given range. All motors with total
impulse anywhere in that range will be in the same motor class. The
smallest letter classification is 'A' power. Motors smaller than that may
be classified as '1/2A' (1/2 the power of an A motor) or 1/4A (1/4 the
power of an A motor).
The first number after the letter (15) is the AVERAGE thrust of the
motor, in Newtons (where 4.45n = 1 pound). The second number (after
the dash, '10') specifies the time delay before the ejection charge fires,
in seconds. The delay time begins AFTER the motor has expended its fuel,
not when the motor ignites.
Any letter after the delay is manufacturer dependent. It typically
indicates a fuel formulation.
Letter Range (NtSec) Comments
1/4A 0.00 - 0.62 Model rocket motors
1/2A 0.63 - 1.25 " " "
A 1.26 - 2.50 " " "
B 2.51 - 5.00 " " "
C 5.01 - 10.00 " " "
D 10.01 - 20.00 " " "
E 20.01 - 40.00 " " "
F 40.01 - 80.00 " " "
G 80.01 - 160.00 " " "
H 160.01 - 320.00 High power rocket motors
I 320.01 - 640.00 " " " "
J 640.01 - 1280.00 " " " "
K 1280.01 - 2560.00 " " " "
L 2560.01 - 5120.00 " " " "
M 5120.01 - 10240.00 " " " "
N 10240.01 - 20480.00 " " " "
O 20480.00 - 40960.00 " " " "
Engines of type 'G' or less, and having less than 62.5 grams (2.2 ounces)
of propellant are classified as DOT Class C Toy Propellant Devices and are
'model rocket' motors. Anything larger is a Class B, 'high power' motor
and their use falls under much stricter regulation. Refer to Section 1.2
for an overview of regulatory issues concerning rocketry and rocket
motors.
2.1.4 Can I legally fly model rockets in my state? What are the restrictions?
Several states still require some type of permit to fly model rockets.
The requirements vary greatly between the states. Also, local
municipalities are free to impose additional restrictions beyond those
defined in NFPA 1122 and any state laws. Check with your local fire
marshal for restrictions in your area. For example, the states
of Rhode Island, and California have stricter regulations than NFPA 1122.
2.1.5 I have a son/daughter that is (6 - 9) years old. Is this too young for
model rocketry? If not, are there any tips for helping to keep their
interest in the hobby?
Model rocket manufacturers all recommend adult supervision for young
children (usually, those under 12). Many parents have had great success
introducing these children to model rocketry. Here are a few of the tips
and suggestions posted to r.m.r:
From [email protected] (C. D. Tavares):
Children under 10 or 11 do best in the hobby when a parent participates
actively with them. Introduce them to simple, skill-level-1 kits with
plastic fin units. Build yourself a rocket at the same time, then go
out and fly them together.
From [email protected] (Jack Hagerty):
My own experience with my son (now 5 1/2, we've been flying since he
turned 4) is not to expect too much sustained interest at a time. Even
though my son has a longer-than-normal attention span for his age
(he'll watch a whole two hour movie!) and loves the whole idea of
building and flying rockets, after 4 or 5 flights (approx. 1/2 hour)
he'd rather go play on the monkey bars at the adjacent school.
This is magnified if there are any kids his own age around (such as his
cousins that sometimes come with us).
From [email protected]:
Watching they should enjoy. Pressing the button they should enjoy.
Prepping with serious supervision. Building simple kits with some
supervision and a pre-launch check. There's a huge difference in
responsibility between kids. One thing to stress is that a lot of very
careful kids will get bored or get pressured by bored friends to do
stupid things when you're not around. I might not let kids have any
access to motors when unsupervised -- and there's no real reason why
that should cause them any trouble. It is possible to make safety fun,
you know. I think that's something that a lot of people miss -- if you
present things that way, it seems to work out. I don't have kids, but
I've got rocket launching friends who do.
From [email protected] (Jim Cook):
I've successfully built an Athena and an America with a 7 year old.
The body tube is pre-painted, the decals are self-adhesive, and they
like the gold or silver chrome nose cone. You can build it in an hour
or two - just let them run around and call them over to help periodic-
ally - "glue here", "cut here", "hold this". They feel it's still
their rocket and that they helped. Estes new E2X series may also be
similarly suitable, but I haven't tried, yet [ed. note: the E2X
series go together with plastic model cement, such as Testors, not
white glue].
Estes' new E2X series is similar in construction to the Athena and
America - they can be built in an hour or two with kids.
Demo a range of motors. Go from 1/2A to A to B with a model to
show kids the difference.
Kids will invariably talk about launching them out of sight or
sticking a fireworks in them. Answer with, "yeah, but I wouldn't
want to wreck my model that I spent so much time building." Making
the kid answer forces him [or her] to think and teaches him [her]
to value his [her] possessions.
From [email protected] (Buzz McDermott):
When my 10 year old son and I started building rockets together about
2 1/2 years ago, we started with some of the level 1 Estes kits with
plastic fin units and nose cones, such as the Athena and Alpha III.
He has also built a couple of the Estes E2X series, which requires use of
plastic cement. He also likes the Quest Falcon (plastic fins) and Estes
Big Bertha (balsa fins) because they are both big enough to use C
motors and not loose the models.
My 7 year old daughter and I started building rockets about a year ago.
She prefers the Quest models with the colored parts. She also finds the
Quest parachutes, with their large adhesive connections for shroud
lines, easier to build. The Quest Falcon is a large, easy to build
model. Now she likes building some of the Level 1 kits with balsa fins.
She has built the Estes Alpha and Quest Sprint.
From [email protected] (John Stewart):
My daughter loves rocketry. She started when she was 3. Get colorful
rockets, build them yourself (e.g. the plastic Alpha III), and don't
fly them too high. (50-100' is more than fine) Let the child count to 5
(or try to!!) and push the button. Let them recover the rockets. Have
say, 5 to 10 rockets loaded, ready to go when heading out. Launch them,
and untangle/fix them either at the field, or at home later, depending
on the child's mood. My 4-3/4 year old daughter is looking forward to
launching, possibly this weekend. We spent a year in New Zealand, but
she still knew all about the rockets, the parachutes, the streamers...
From [email protected] (Robert Sisk):
People interested in easy to build model rocket kits for the younger
crowd should check out QUEST models. Some of the parts are color
coded (centering rings, engine blocks, engine mount tube) and the fins
of some models are plastic. Some of the fins are supplied as a single
unit that you glue into place. Fast, easy, and with little or no
sanding!
2.1.6 Is there any way I can buy model rocket kits, parts and engines at less
than full retail?
Two mail order houses have been recommended several times by posters to
r.m.r. They are Belleville Wholesale Hobby and Magnum Rockets Hobbies and
More. Belleville sells MRC at 40% off list, Custom Rockets at 35% off list
and Estes at 30% off list. There is a minimum order requirement. Magnum
sells most all of the major model and high power rocket lines, including
Estes, Custom, Vaughn Brothers, NCR, Aerotech, LOC and others. Both
Estes and Aerotech model rocket motors and reloads are sold.
Refer to the 'Addresses' section of Part 1 of this FAQ for their addresses.
The following individual has been mentioned as a source for cheap 18, 24,
and 33mm Estes-style body tubes (BT-20, -50, and -55, respectively), if
you are will to buy by the dozen (or more):
Lou Scavone
41312 Memphis Drive
Sterling Heights, Michigan
(313)739-3058
Another potential source of less expensive body tubes is:
Fred Shecter
20505 E. Clear Spring Court
Walnut CA 91789
Fred is with the LA Rocket Society. He is purported to have craft paper
tubes in lengths up to 34-36 inches.
In Canada:
OAS (Orleans Automation Systems) Rocketry Division
Suite 606, 116 Albert St.
Ottawa, Ont.
K1P 5G3
(613) 233-1159
(613) 830-5811 (fax)
If you do a fair amount of flying, Estes sells a 24-pack of engines called
the Flight Pack. It comes with 6 A8-3, 6 B6-4, 6 C6-5, 6 C6-7, recovery
wadding and igniters. It generally retails between $25-28, which is less
than the list price of the materials included. This can also be purchased
at an additional discount from some mail order houses.
Quest motors have been recommended by several r.m.r posters. At the
present time, they retail at less than the Estes equivalents. They can
also be purchased direct from Quest 'bagged' in quantities of 10 or more.
'A' motors can get to less than $1 ea. when bought 50 or more at a time.
'C' motors get down to around $1.25.
You might also investigate your local NAR section, if one is located
convenient to you. Clubs such as NAR sections often arrange discounts
with local hobby merchants. Several of the clubs also have at least
one member selling parts and supplies at discount, mostly to the
club members.
2.1.7 I've had a large number of motors CATO recently. The engines are only
about 2 years old. I've had them stored in my (attic/garage/basement).
From [email protected] (Jim Cook):
Black powder motors tend to suffer catos when they are temperature
cycled. If you expose them to heat, be it storing them in the attic,
on your car's dashboard, or in your metal range box in the hot sun on
the launch field, you may have problems. The engine expands with the
heat, but when it cools, the propellant separates from the casing
inside This causes the propellant to burn faster due to burning on the
side generating more pressure than was designed for, and ...boom...
Storing black powder motors in a damp basement can cause the compressed
clay nozzles to soften and also blow out. If you must store your motors
in a damp/humid area, put them in a zip lock plastic bag.
[Note: There is an excellent article by Mat Steele in the May/June 1992
issue of Sport Rocketry. This article goes into the
theoretical reasons why black powder model rocket motors fail]
2.1.8 Is it safe to use my old rocket engines from <nn> years ago?
From [email protected] (Jim Cook):
I've had properly stored engines from 1972 and 1975 work just fine.
If you suspect a motor, fire it by burying it in the ground with just
the nozzle showing, pointing up and use your launch system to ignite it
as usual. [Note: be sure and stand at least 15-20 feet away from the
motor when you fire it: Buzz]
2.1.9 What's a good way to find other rocket enthusiasts in my area? How
can I found out about local rocket clubs?
The NAR sends a complete list of its local sections (NAR sanctioned
clubs) with each new member's information packet. If there isn't
a sanction near you they have a service to send you a list of
other NAR members in your area, so that you can form your own
section.
2.1.10 Are the Aerotech composite motors the same size as Estes/MRC/Quest
motors?
Aerotech makes the following 'standard' retail motors in -4, -7 and -10
second delays. The first two motors are the same size as Estes A-C motors.
The second two are the same size as Estes D motors. There are some other
24mm motors that may still be available from Aerotech that are longer than
Estes D motors. There are/were a couple of F's and a 90NS baby G (the G42).
These are not considered 'standard' motors by Aerotech and are relatively
expensive for their power. Of the non-standard motors, the G42 may be the
easiest to find.
Motor Size Power Same Size As
D21 18x70 mm 20NS Estes/Quest/MRC A-C
E25 18x70mm 22NS Estes/Quest/MRC A-C
E15 24x70mm 40NS Estes D motor
E30 24x70 40NS Estes D motor
Aerotech makes and sells reloadable motor casings and reloads in 18,
24 and 29 mm sizes. The 18mm is the size of an Estes C motor. The
24mm is the size of an Estes D or Aerotech E motor. The 29mm is the
size of an Aerotech G motor. Aerotech High Power, formerly ISP Consumer
Rocketry division, makes a 60NS F and 100NS G casing.
2.1.11 Can I use Aerotech or other composite motors in my Estes rockets?
Yes and no. They are the same size. Composite motors have 2 to 3 times
the power of comparably size BP motors. Balsa-finned 18mm powered models
tend to loose body parts in quantity when launched with a D21 or E25.
The ejection charges seem to be hotter, as well (IMHO). The same holds
true for Aerotech 24mm motors. Care should be taken before launching a
24mm-based model on an E15, let alone an E30. I have an old MegaSiz that
I fly on E15-10's. Works great. The Estes Saturn V flies well on E15's,
too. E30's tend to shred all but the strongest D models, though. E30's
also tend to relocate motor mounts to someplace OUTSIDE of the rockets, as
well. If I plan to use E's in an Estes model I make it a point to reinforce
the motor mount, especially for EM-2060 or EM-2070 mounts. You also want
to use an engine block (a 2050 adapter ring works great) in addition to
the metal clip. IMO, I would also reinforce fin/body tube joints. Five
minute epoxy fillets work great. Generous cyano fillets also seem to work
well. White glued fins don't seem to survive E15/E30 launches with any
consistent success (i.e., the failure rate tends to be > 50% :-). Many
modelers also recommend that stronger 24mm motor tubing, such as that from
LOC or Aerotech, be used for models flying with composite motors. The
stronger tubing holds up better to the ejection charges of the composites.
2.1.12 I've seen a new E motor from Estes. Is it the same as the Aerotech E
motors?
The Estes E motor is black powder based. It is the same diameter as Estes
D motors and Aerotech E motors (24mm). However, it is 3/4" longer than
either (i.e., 3.5"). The Estes E15 motor has been NAR certified and
is available as E15-4, E15-6, E15-8 and E15-P (plugged). The NAR certified
total impulse for the Estes E15 is around 30NS, compared to 17NS for an
Estes D12 motor and 40NS for an Aerotech composite E15. Be warned of two
things...(1) the E15 from Estes is an end-burning motor and has a very
flat thrust curve, meaning it can't lift a model a D12 won't lift; and
(2) these motors have a HOT ejection charge, so use extra wadding and
a longer shock cord. The Estes E15 would be more accurately labeled an
E12.
WARNING: Estes E15 motors manufacturerd prior to 15 Dec 1993 have been
reported as having an extremely high failure (CATO) rate. These
motors may be identified by their date codes. Any Estes E15 motor
with a date code of 15X12 or earlier is suspect. The easy way to
remember this is to treat any motor with a date letter code of 'X'
as potentially suspect. Motors manufactured in 1994 will have a
date letter code of 'Y' and have been reported by Estes as having
the problem fixed.
2.1.13 Will my Estes launch system work with Aerotech composite motors.
The classic Estes or Quest or MRC 6 volt launch system will not reliably
ignite the Copperhead (TM) igniters that come with Aerotech motors, and
Estes Solar Igniters (TM) will not ignite a composite. These motors need
12 volt systems for reliable ignition.
2.1.14 Can I use Aerotech composite motors as boosters in my multi-stage
rockets?
Basically, NO. Black powder booster motors will not ignite composite
motors. Therefore, you cannot use a composite upper stage in a traditional
multi-stage, black powder rocket. Also, there are no composite booster
motors currently in production. They all have delays (4 seconds being
the shortest current delay from Aerotech, for example) or are plugged.
Typically, you cannot (and should not) use these as boosters in standard
black-powder multi-staged rockets.
If you want to use composite motors in multi-stage models then you have to
use other methods of igniting the upper stage (whether black powder or
composite) than are used with black-powder-only rockets. One method is
to electronically ignite the upper stage motor using a mercury switch to
complete an electrical connection to a capacitor at first stage burn-out.
This, in turn, sets off a flash bulb/thermalite fuse combo which ignites
the upper stage motor. Another method is to ignite lengths of thermalite
fuse at the time the booster is ignited. The length of fuse determines
the delay before the upper stage is ignited. Refer to the 'Other Sources
of Information' section in Part 1 of the FAQ. The NCR High Power technical
reports on staging composite motors is applicable to multi-staged,
composite motor powered model rockets as well.
2.1.15 How can I tell the age of my Estes motors?
Estes uses a date code on their rocket motors. It's of the form XXYZZ
(example, 25T9) where the first number is the day of the month of
manufacture, the letter is a code indicating year of manufacture, and the
last number is the month (1 = January, 12 = December). Date codes
run progressively through the alphabet, as follows:
T 1989
U 1990
V 1991
W 1992
X 1993
and so on ...
In the early 70's, Estes motors had the actual date stamped on them.
2.1.16 I've heard about reloadable motor technology for model rocket sized
motors. I've also heard they have been banned. What is their current
status?
In 1992, the DOT banned all rocket motor reload kits, from all manufac-
turers, from interstate commerce. This meant that they could still be
sold at retail, but manufacturers, mail order houses, etc., could not
mail them to customers. Aerotech has recently obtained Class C
equivalent certification for many of there model rocket class reload
systems. Essentially, Aerotech may now ship all of its 18mm, 24mm, 29mm,
33mm and 38mm reloads via UPS. Two caveats: To keep the CPSC happy,
sales of Aerotech reload hardware and reloads is restricted to those
18 years of age or older. Also, not all of the reloads have been
certified by NAR or Tripoli. This does make them illegal. It does
mean that you are in violation of NAR and Tripoli safety codes if you
fly uncertified motors or reloads.
2.1.17 My flying field is so small I keep losing my rockets. What can I do?
DON'T GET DISCOURAGED. Everyone loses rockets. It's part of the hobby.
There are ways to minimize this when you're forced to fly in smaller
fields, though. The following is a consolidation of tips posted to r.m.r
by numerous individuals:
Recovery Modifications:
1. For smaller rockets, use a streamer instead of a parachute. This
can be done with rockets of up to BT-50 body tube size and up to
18" long. Be sure and check rocket weight, though. If the model uses
heavy plastic fins you might still want to use a parachute.
2. Reef the chute lines to reduce the effective surface area. Tie or tape
the shroud lines together 1/3 of the way from their end. This reduces
the shroud lines to 2/3 of their original length and prevents the chute
from fully opening. The rocket will come down faster and drift less.
3. Cut out the Estes or Quest logo from the center of the chute. This lets
more air spill through the chute and reduces its drag. Be careful to cut
out the whole logo. Cutting only a small whole (say, less than 2" in
diameter) can improve the chute's stability and actually make it lift
better and drift further.
4. Use a smaller chute. Try cutting down an 18" chute to a 15" chute, or a
12" chute to a 10" chute.
5. Use longer ejection delays. If a B6-4 ejects the parachute right at
apogee, use a B6-6 to let the rocket come down a little before popping
the chute. Less time chute is open equals less drift. Take care in
making the chutes and recovery attachments extra strong, though, as
the descending model will put more strain on the recovery system than
if it were to deploy at apogee.
Other Suggestions:
1. Find a different field. If you fly alone, try and find a local rocket
club. The odds are the club will have found a better field in which
to fly.
2. Fly larger rockets. A Big Bertha on a B6-2 will drift a lot less
than a Sky Hook or other small model on a B6-4 or B6-6. Larger models
have more impressive lift-offs, as well. Larger diameter rockets
don't fly as high and come down faster than the really small ones. The
big ones are also easier to spot in high grass, weeds, trees, etc.
3. Use smaller motors. If the recommended motors for a rocket are, for
example, A8-3, B6-4 and C6-5 or C6-7, try it on A8-3's first. If
the model lands well within the recovery area you can then decide if
the larger motors will allow the model to be retrieved.
4. Launch rockets at a slight angle into the wind. The rockets will
weathercock and deploy recovery systems upwind. If all goes well, they
will land closer to the launch site.
2.1.18 Are Jetex engines still available? Where can I get them?
Although, technically, jetex type products are NOT model rocket motors and
do not fall under NAR/NFPA guidelines and safety codes, a number of
questions do pop up about these on r.m.r. The following sources have been
quoted on r.m.r as selling Jetex products:
Peck Polymers
P.O. Box 2498
La Mesa, CA 92041
Doylejet
P.O. Box 60311
Houston, Texas 77205
(713) 443-3409
----------------------------------------
Section 2.2: Born-again Rocketeers
I have been out of model rockets for many (i.e. <nn>+) years now.
All I ever used were Estes/Centuri/FSI kits. I never knew of anything
else. I would appreciate it if someone could tell me more about
what is going on in the sport/hobby currently.
2.2.1 Who's Left, Who's Not & Who's New
Basically, it's all pretty much the same, or totally different,
depending on your interests. Estes is still Estes. Most of their kits
are still the same materials, etc. The trend for the last 10 years has
been for Estes to sell simpler and simpler kits. There are lots of
plastic nose cones and fin units (already around when you were active
before). There are now kits with pre-slotted body tubes and plastic
fins (as in the Estes E2X series). Lot's of good stuff for beginners
and kids. Estes still makes engines in the 1/2A - D range, all black
powder.
Flight Systems is still here, selling kits and black powder engines in the
A-G range.
Centuri, sadly, 'went away' in 1980. Daemon Industries bought both Estes
and Centuri in the 1970's. They operated both companies as independent
units for several years. Finally, Centuri was dissolved and its products
absorbed into Estes. Every now and then an old Centuri kit surfaces
under the Estes banner.
Now for 'who is new'. First, in model rocketry there is a new kid
on the block: Quest. This is Bill Stine, some ex-Centuri people
and others. They are a direct competitor to Estes. They have a line
of kits and engines (A-C). Good quality. Cheaper than Estes. Some
other companies making and selling model rocket kits include Vaughn
Brothers and Custom Rockets. See Section 1 for addresses.
Aerotech, Thoy, LOC/Precision, and North Coast Rocketry are all relatively
new names in the business. These companies cater to both larger model
rocket and high power rocket markets. A couple of outfits make kits
using newer technology materials, including phenolics, fiberglass, and
composites. These include MRED Industries, Public Missiles and Dynacom.
Be prepared to pay more dollars for the more advanced materials.
If you were into competing you might have been familiar with Competition
Model Rockets (CMR). They are now defunct but there are constant rumors
of a rebirth 'sometime in the near future'. Other companies have stepped
in to fill the space left by the exit of CMR. See the section
'Competition' for some names and addresses.
A lot of the 'neat' Estes kits of the 60's and 70's are no longer
available. However, Estes is bringing them back (one by one) in so-
called, 'limited run collector series'. The original 'Mars Snooper' and
'Maxi Honest John' kits have been re-issued, so far. More releases are
supposed to be forth- coming. WARNING: Be prepared to pay a much higher
price for these re-released kits. Remember that inflation has led to
some items having much higher prices now than in the mid 60's and 70's. No
doubt Estes will take advantage of the demand for the re-released kits,
as well, and charge an additional premium.
2.2.2 Changes in Motor Technology
The big changes have come in motors. Expendable composite fuel motors
are now available in D-G range for model rockets These motors
use ammonium perchlorate for fuel, similar to the rocket boosters on
the space shuttle, allowing them to pack two to three times the power
in the same space as a black powder motor. The D motors are the
same size as Estes A-C motors (18x70mm). This D is also a full
D power rating of 20 Newton-seconds, versus the Estes 24x70mm D of about
17 Newton-seconds. There are a couple of E motors the same size as
Estes D motors. All of the motors give Estes kits an incredible ride,
if the models hold together. The E-G power ranges are now sometimes
referred to as 'medium power'. These are usually still model rockets
(i.e., under 1500 gram launch weight). These kits require stronger
construction methods and materials than typical model rockets. Put an
Aerotech D21 or E25 in your old Big Bertha at your own risk!! You're
likely to end up with a model with no fins (i.e., a complete 'shred').
Another new trend is 'reloadable' motor technology. With reloadables
you have a metal motor casing that you manually reload with solid fuel
pellets, delay and ejection charge for each flight. The casing is
reusable. Reloadable motors are available in everything from 18x70 mm
(with B - E power), 24mm, (with D - F power), 29mm, 38mm, and much
larger. Again, you can get all the way up to 40,000+ Newton-seconds of
total impulse.
2.2.3 High Power Rocketry
Now there is also HIGH power rocketry (HPR). These are rockets with
motors up to type O (with greater than 40,000 Newton seconds of impulse).
There has been a lot of discussion about high power recently. You have to
be a member of either the NAR or Tripoli to fly rockets with H motors or
above. To fly with H or above both organizations require that you be
'certified' by safely demonstrating a successful flight with a high power
model in the presence of one or more 'qualified' members of the
organization. There is now a HPR safety code as well as the original
model rocketry safety code. There are expendable and reloadable
(discussed below) HPR motors available. They are increasingly
expensive as the power goes up ( $10 for a G up to hundreds of dollars
for a really big (O) motor). High power rockets start where model
rockets leave off (i.e., > 1500 grams). High power models weighing
more than 50 pounds are not uncommon.
Oh, yes, HPR requires a duly authorized, signed-in-blood (in triplicate,
etc.) FAA waiver for each day you wish to fly. It is ILLEGAL to fly
high power rockets without a proper waiver. See section 3.1.7 for more
information on FAA waivers.
2.2.4 Electronics Advancements
Advances in electronics technology have created many opportunities for
new ideas in consumer rocketry. Electronic ignition of upper stages of
multi-staged rockets is now common. Several altimeters more recording
maximum altitude are available. Electronic deployment of recovery
devices, as well as deployment based on altitude, is now practical.
The FAQ sections on High Power Rocketry and Payloads have more to say
about this. See Section 1.3.3 for addresses of some companies selling
rocketry electronics.
2.2.5 Regulations, Regulations, Regulations
There is some good news and some bad news concerning rules and
regulations relating to consumer rocketry. On the positive side, you
can now buy up to G power motors in most states. Also, some states, such
as New Jersey, have recently relaxed restrictions on model rockets.
There is a menacing down side as well, though. Read the current
regulatory summary in Part 1 of the FAQ. All of this has been a little
confused and unsettled over the past two years.
----------------------------------------
Section 2.3: Model Rocket Construction, Finishing and Flying Tips
This section includes tips and suggestions on various topics having to do
with construction and finishing techniques. These have been posted to
r.m.r or mailed to the moderator by way of r.m.r request. Refer to this
same section in Part 3 of the FAQ (High Power) for additional tips,
oriented towards high power and advanced rocketry requirements. Even more
tips can be found in the Scale Modeling section of Part 5.
2.3.1 Cutting, Sealing, Attaching Fins
From [email protected] (Jim Cook):
Skip using glue W/ balsa dust, dope, or any other junk for filling the
grain in balsa fins or nose cones. Use Elmer's "Fill 'n Finish" diluted
with water to a thick paint (like white glue is) and paint it on.
Non-toxic and a coat or two will do. Use Elmer's "Carpenter's Wood
Filler" thinned similarly to fill the spiral in body tube. Both come
in a white plastic tub with an orange lid. Note - the latter is
harder to sand, so don't make the mistake of using it on balsa as it
will require a lot of sanding.
From [email protected] (C. D. Tavares):
Fill your fins BEFORE attaching them. (Don't fill the root edge).
From: [email protected] (David M.V. Utidjian):
[To hold fins in place and aligned while drying I bought an Estes
fin alignment kit]. At 15-16 bucks it seems a bit
expensive but is well worth the aggravation and time it saves. You
can even make your own if you are handy. I just set up my body tube
in the jig and then check the alignment of all of the fins to the body
tube. Then I use a thin bead of 5-min. epoxy. and in ten minutes I am
done. When I do the fillets I can do them all at once but don't have
to worry about the softening the glued on fins so they droop. You
still have to lay the model on its side though but only for 5 minutes.
2.3.2 Body Tubes (Cutting, Joining, Filling)
From [email protected] (C. D. Tavares):
[On cutting Estes-style body tubes]
The simplest and best I ever used was Howard Kuhn's jig from the old CMR.
It's a simple piece of wood L-angle molding, with a notch for a razor
blade cut into one side (from the wing toward the elbow) at one end.
The only other parts are a wood block and a large black spring clip (the
kind you hold really thick reports together with). If you want, say, a
6" piece of tubing, you set the block 6" away from the razor notch and
clamp it there with the spring clip. Now lay the tube down the L-angle,
butting it up against the wood block. Insert the razor blade, press
lightly, and turn the tube. (Put a dead engine into it if the tube is
the right size to fit one.) Three to six turns, and you have an edge
that looks factory-cut.
----
( ) <- spring clip | <- razor (edge on,
/ \ | sharp edge down)
____________---------___________________________|_______
| /_| |__/| | |
| | |_______| || angle molding | |
| | wood block || |
|----------|____________|/-------------------------------j
/ lay tube here and spin it /
/________________________________________________________/
From: [email protected] (Tim Harincar)
[On cutting Estes-style body tubes]
When I cut tubes, I always wrap the tube with about two
layers of drafting tape with the edge of the tape along
the cut line. This accomplishes two things: First the
thick tape edge providing a excellent knife guide. Second,
you can assure a straight cut. If the tape wrinkles when
you wrap the tube, you know it is not on straight; simply
remove the tape and try again until you know its down flat.
Drafting tape is better than regular masking tape because it
has almost the same thickness but is made to be removed.
This method is in addition to reinforcing the inside with
a stage coupler or spent motor. Also, always use a new
x-acto blade for the best cut.
From Jim Bandy (NAR member not on net):
Use a piece of aluminum 'angle iron' for joining body tubes. Place one
tube in the angle, insert and glue the joiner, then insert and glue the
other tube. It give very straight joins. The angle can also be used
for marking fin lines on body tubes, etc.
2.3.3 Parachutes
From: [email protected] (Tim Harincar)
Making your own parachutes is pretty easy. Start with the desired
material (usually mylar or a light plastic). Make a cutting pattern out
of cardboard by first drawing a circle that will be the maximum size
of the chute (i.e. 16"). Take a compass [or] something that will give
you an accurate radius of the circle. Pick a point anywhere on the
circle and using the radius as a length draw an arc that crosses the
circle. At the point where the arc crosses, reposition the compass on
that point and draw another arc. Keep doing that all the way around
the circle - you will end up with six points including the starting
point on the circle. Connect these points with a straight edge and
Presto! a hexagon. Cut out the hex from the cardboard (I use artists
matboard...) and this is your cutting template. Lay the template on
the material and using an EXTREMELY SHARP XACTO KNIFE cut along the
outside of the template. Make shrouds from a heavy gauge thread -
cut three equal lengths twice as long as the diameter of the chute and
connect the ends to corner points adjacent to each other.
From: [email protected]
I usually build 12-24 line round chutes out of Estes material (just cut
around the outside of the red and white circle and attach at the red
/white boundaries) because they look more like real parachutes. I use
embroidery floss for shroud lines and separate the 6 strands (for 12
lines - use two lengths for a 24 line). This makes a strong chute.
With out crossing the lines over the top of the canopy, I've only had
one failure of a 12 line chute (an EL that tipped off dramatically -
i.e. cruise missile) and never had a 24 line fail. In the 10 years
I've been back in the hobby and using this technique, my shroud lines
have always come out the same length (within a couple of percent
tolerance).
From: [email protected] (Hal Wadleigh)
1. Use fisherman's snap swivels for your attachments. It lets you
store 'chutes separate from rockets and helps prevent fouling due
to spin at deployment.[Note...modelers have always reported mixed
results with snap swivels; they have been known to fail...Buzz]
2. Use nylon coat thread for shroud lines on homemade 'chutes (and
plastic bread wrappers are the best cheap 'chute material).
3. Pay special attention to the security of the attachment points.
Those standard stickers often look secure, but are actually not
attached. A small knot in the part of the shroud line under the
sticker serves as a good anchor point (with the rest of that part
looped around the knot, as per standard practice).
4. Very small 'chutes should be crossform type. Cut about a 5" square,
then take out about 1.25" squares from each corner. Attach 4 lobes
of shroud across the flat ends and secure as above. Be careful to
use small stickers for the corner attachments. These make good
substitutes for streamers in .5" body tubes and can also be used as
drogues to help in the deployment of large 'chutes [A note from
[email protected] (C. D. Tavares): Either round off the inside
corner of that 1.25" square or reinforce the angle with something.
Otherwise, it's a really handy place for the parachute to rip
during a fast deployment.]
From: [email protected] (Greg Smith)
Nylon coat thread is very good for small, lightweight competition
parachutes, but it's not real strong and does have a tendency to melt if
it encounters a bit too much ejection charge heat. For sport and
payload models with 12" - 24" plastic 'chutes, I use 15 lb. *braided*
nylon fishing line. It's thicker than the coat thread, similar in
diameter to the Estes cotton stuff, but tremendously stronger. In the
last fifteen years, of the plastic parachutes I have built using this
line (and always crossed over the top of the 'chute for reinforcement),
I have had *zero* shroud line or attachment failures. The braided line
has a hard, smooth surface that doesn't encourage tangling, and it
doesn't unravel where cut.
From: [email protected] (Rusty Whitman)
I've tried about everything to keep shroud lines from pulling off of
plastic or mylar parachutes. Those little tape disks are just about
worthless. Tying knots and cyano'ing the ends helps but you still
have problems. I don't know why I never thought of this before but I
ran across a roll of duct tape in my closet and knew immediately that
was the answer. I cut out some little squares of duct tape and
attached some lines to a parachute and they won't pull free without
ripping the plastic. I don't know who invented duct tape but they
deserve some kind of statue, its got more uses than a paper clip.
2.3.4 Launcher and Launching Tips
From: [email protected] (Tim Harincar)
[concerning an ongoing conversation about piston ejection systems]
Ed LaCroix's piston used a piece of kevlar and a stage coupler. Take
a piece of heavy cardboard or wood and glue it over one end of the stage
coupler. Drill a small hole in the center of the wood large enough for
the kevlar to pass. Sand the wood/couple smooth so it has a good slide
through the tube. Drill four or five 1/8 - 1/4" holes in the side of
the coupler just under the piece of wood. Attach one end of the kevlar
line to the motor mount, and run the other end through the hole in the
coupler. Align the coupler so the holes extend just beyond the end of the
tube and tie a knot in the kevlar. The idea is to let the coupler
slide along the kevlar until the holes are exposed to the outside, then
the knot stops the slide. Because the kevlar doesn't contact the tube
wall, it won't slice it.
From: [email protected] C.D. Tavares
[concerning an ongoing discussion about blast deflectors]
I've had first hand experiences with several types of metals. I've never
found a piece of aluminum that was worth dog-doo as a deflector. In the
higher engine ranges, even steel will give you problems, especially with
maintenance. Stainless isn't much help, since it still cruds up.
What we use are discarded grinding wheels. Fireproof, non-conductive,
free, plentiful, large, and pre-drilled. The only negative on these is
that when an engine catos they tend to lose large chunks or crack in
half. This happens to us maybe three times per year, but as I say,
they're free and they're plentiful.
2.3.5 Alternatives to Recovery Wadding
From [email protected] (Jack Hagerty):
Just go down to your local building supply store and get a bale of
cellulose wall insulation. This is just shredded newspaper treated in
the same fire suppressant [as Estes recovery wadding]. A $5 bag will give
you enough wadding to last years!
From [email protected] (Warren Massey):
I have found crepe paper to be a must more cost effective alternative.
It comes in either sheets or rolls (I prefer the sheets) in a variety of
colors and is every bit as flame retardant at a fraction of the price. I
can even get several flights off a single ball of wadding. It is somewhat
stiffer than the tissue but I've never found that to be a drawback.
Unattributed:
A piston ejection system works well on rockets of BT-60 size or greater.
Pistons eliminate the need for recovery wadding of any type. Plans
for a D powered rocket using piston ejection may be found on sunsite.unc.edu
in the file 'pub/archives/rec.models.rockets/PLANS/dust-devil.ps'.
The rocket was designed and drawn by [email protected] (Joe Pfeiffer).
2.3.6 Nose Cones
From Chris Jennison
To keep nose cones from wobbling and coming out asymmetrical when using
an electric hand drill as a lathe...
Use a blank (dowel, broom stick or balsa block) 1/8 inch larger
(diameter) than the nose cone that you need. Drill a 1/4 in. diameter hole
as close to dead center as you can and push in a 1/4 in dowel. Dowel
length should allow the nose cone end to seat against the face of the
drill chuck. Find dead center by running the drill clamped in a vise at
moderate speed & slowly move a soft pencil toward the end at what
appears to be the center of rotation. After a couple of tries you will
find the center because your misses will draw concentric circles like
a bullseye. Now remove the dowel from the drill, clamp the shoulder end
in the vise and rough shape the nose cone with a file or rasp using the
marked center as a guide. Final contouring and finishing is done in the
drill with progressively finer sand paper.
2.3.7 Clustering Model Rocket Motors
The advent of composite model rocket motors in 'standard' black power
sizes (18 and 24mm) has led to an increase in the use of composite motors
in cluster rockets. Mixed black powder/composite clusters are also
becoming popular. In particular, clusters of 3 or 4 composite
motors, or a composite core motor with outboard black powder motors,
are being seen more. These offer special ignition challenges. The old
black powder techniques don't work when composite motors are
involved. The most common method for clustering Estes type black
powder motors is to use multiple Solar igniters and clip whips. Flash
bulb to sheathed thermalite is the most common composite ignition
method. Although flash bulb ignition has been used for years, there
have been safety concerns over its use. Here are some suggestions from
rmr posters:
From [email protected] (Peter Alway):
I cluster black powder motors with Solar igniters wired
in parallel and a car battery for power. I stuff igniters
with little balls of tissue paper wadding to insure they
stay in place. My general rule is only to cluster with
a technique I use regularly for single-engine models,
as reliability has more to do with experience and my
current state of skill than with the particular technique.
From: [email protected] (Glenn Newell)
My technique for clustering composite motors is to use equal length
pieces of thermalite with 1/16" heat shrink tubing as a sleeve. I
leave about a 1/2" unsheathed in the motor and about one inch unsheathed
on the other end (I don't shrink the heat shrink, it just happened to be
around and the right size). I tape all the ends together around a single
solar igniter. No flashbulb problems here!
From: [email protected] (Bill Nelson)
I prefer to use a short section of Thermalite, with igniter wires,
inserted into each motor - the wires are taped to the motor for security.
There is no need for an igniter for the Thermalite. Simply remove the
cloth wrap, and all but one of the spiral metal wires. Wrap the end of
one wire to one end of the thermalite and the end of the other wire to
the other end. You can use anything from about 22 gauge wire (if it will
fit in the grain slot) to about 28 gauge. The free ends connect to the
controller ignition wires. When the relay closes, the Thermalite wire
wrap is essentially vaporized instantly. I have never seen the
Thermalite fail to ignite.
Readers are also directed to check out the NCR Technical Reports #1 &
#2, on black powder and composite clustering, respectively. Although
they are a few years old, they still contain valuable information.
|
| 33.12 | FAQ Part 3 of 5 | VERGA::KLAES | Quo vadimus? | Wed Mar 02 1994 12:36 | 993 |
| Article: 15951
Newsgroups: rec.models.rockets
From: [email protected] (Buzz McDermott)
Subject: (FAQ) Frequently Asked Questions - Part 3 of 5
Organization: NETCOM On-line Communication Services (408 241-9760 guest)
Date: Wed, 2 Mar 1994 04:33:35 GMT
Rec.Models.Rockets FAQ (Frequently Asked Questions): Part 3 of 5
Last Modified: 1 March 1994
*** PART 3: HIGH POWER ROCKETRY
Section 3.1: On To High Power
Review: A High Power rocket is a model weighing more than 1500 grams (3.3 lb)
or containing more than 125 grams of propellant or containing any
motor with more than 62.5 grams of propellant or containing motors
totaling more than 320NS total impulse.
Several issues dealing with high power rockets are under regulatory
review at present. Refer to Section 1.2 for a summary of current
regulatory issues.
3.1.1 I'm a successful model rocketeer. What do I need to get into HPR?
When this question was posted to r.m.r a while back, these were the pre-
dominant suggestions and tips:
- Start with E/F/G kits with 29mm motor mounts from NCR, LOC or Aerotech.
These should be the easiest to build.
- Read and become familiar with the NAR and/or Tripoli High Power Safety
Code(s)
- Get familiar with and use expendable motors before jumping into
reloadable technology.
- Join a high power club if possible (local NAR section or Tripoli
prefect).
- Be very careful of the construction differences between model and high
power rockets. You HAVE to build higher power rockets to be more sturdy
than model rockets (see the next question).
- If not already a member, join both the NAR and Tripoli (if you can
afford high power rocketry, you can afford to join and support both
these organizations).
3.1.2 What are the major differences between model and high power rockets,
besides size and engines? Are they built differently?
Above and beyond all else, high power rockets are built much stronger
than standard model rockets. This is due to the higher speeds and
acceleration achieved by these models. Some of the construction
differences are:
- High power rockets have stronger, thicker body tubes
- They have MUCH stronger engine mounts, bonded using epoxy rather
than white or yellow glue
- Engine mount rings, adapter rings, etc., are typically made from
1/8" or thicker aircraft plywood, rather than paper or balsa
- Fins are typically made from plywood or waferglass, not balsa; (thick)
balsa fins have been used on E and F powered models, but they have to
be heavily reinforced
- Fins are often mounted into slots in the body tube (TTW mounting); some
are epoxied TTW and directly onto the motor tube (motor tube butt mount)
- Parachutes are larger and typically made from some type of fabric
(plastic chutes are not strong enough, usually)
- Heavy elastic shock cords with steel braid or Kevlar shock line
are used rather than rubber for shock cords, and these are typically
epoxied to the motor mount or a bulkhead
3.1.3 Are there any national organizations to which I could join?
There are two national organizations associated with high power rocketry.
The first is the NAR. It supports both model and high power rocketry.
The second is the Tripoli Rocketry Association, which was formed by NAR
members who felt the NAR was taking too much time getting a high power
program together. Tripoli is oriented more towards high power
rocketry. Both organizations offer certification programs for individuals
wishing to purchase high power engines. Anyone wanting to get involved
with HPR is encouraged to join one or both organizations. The addresses
for both are in the section 'Some Commonly Sought Addresses'.
3.1.4 What is a 'reloadable' motor. Are they worth the price? Are they legal?
A reloadable rocket motor is a metal cylinder with screw-on end pieces.
Solid propellant and time delay are purchased separately from the motor
casing, in 'reload kits'. These kits contain all of the expendable,
non-reusable materials for a single flight. The cost of the reload is
significantly less than the cost of an expendable motor (when talking
about F sizes and up). Reloadable rocket motors are not currently
banned by the NAR. They are prohibited from competition at this time,
though. The DOT has ruled that many high power and some model rocket
reloads are banned from interstate commerce. Legally shippable reloads
are summarized in two places, 3.1.5, below, and 2.1.16 in Part 1.
You should also read all of Section 1.2.
YOU MUST BE A CERTIFIED MEMBER OF A QUALIFIED ORGANIZATION TO PURCHASE OR
USE RELOADABLE HIGH POWER MOTORS. See section 3.1.9, below, for
information on becoming certified to use high power reloadable motors.
WARNING: IT IS HIGHLY RECOMMENDED BY r.m.r CONSENSUS THAT YOU DO NOT
ASSEMBLE AND/OR PREP A RELOADABLE-TYPE MOTOR UNTIL JUST PRIOR
TO ITS USE (I.E., ON THE FLYING FIELD). *** UNDER NO
CIRCUMSTANCES SHOULD ASSEMBLED RELOADABLE MOTORS BE STORED WITH
IGNITERS INSTALLED ***
3.1.5 What is the current legal status of HPR motors? I've heard the DOT has
banned them. Is that true?
FIRST, YOU MUST BE A CERTIFIED MEMBER OF A QUALIFIED ORGANIZATION TO
PURCHASE OR USE CLASS B MOTORS OF ANY TYPE. See section 3.1.9, below, for
information on becoming certified to use Class B motors.
The DOT has NOT banned high power motors. Class B *disposable* motors
are available to certified individuals and organizations. Class B
explosives do have severe shipping restrictions, though, and high power
motors are subject to these same restrictions. High power reloadable
motors are not currently banned for use by certified individuals, but
many of the reload kits have been banned from transportation by the DOT.
According to Aerotech, Class C equivalent shipping classification has been
obtained for the following 'High Power' reloadable motors:
Motor Total Impulse Fits Casing/Motor System
G75J-S,M 159NS RMS 29/180
H128W-S,M,L 180NS RMS 29/180
H238T-S,M,L 162NS RMS 29/180
H97J-S,M 169NS RMS 29/240
H180W-S,M,L 240NS RMS 29/240
H123W-S,M,L 214NS RMS 38/240
H242T-S.M.L 235NS RMS 38/240
I161W-S,M,L 329NS RMS 38/360
I357T-S,M,L 343NS RMS 38/360
I211W-S,M,L 436NS RMS 38/480
I284W-S,M,L 600NS RMS 38/600
Note that NO 38mm BlackJack reloads are included in this list.
See section 1.2 for a regulatory summary.
38mm BlackJack reloads, and all larger reloads, may now be shipped, but
they must be shipped partially loaded in their casings. They are then
shippable as Class B devices (i.e., via Federal Express, airport-to-
airport).
3.1.6 What are these different 'types' of composite motors I hear about (White
Lightning, Black Jack, Smokey Sam, etc.)?
These are all manufacturers' names for various formulations of 'stuff'
they have added to the propellants to get specific pyrotechnic effects.
Black Jack (Aerotech): low(er) average thrust engine which produces a
dense, dark exhaust to aid in tracking. Also has a distinctive roar.
Blue Thunder (Aerotech): high level average thrust engines with a bright
violet-blue flame and very little visible exhaust. Designed for high
thrust, high acceleration lift-offs.
Firestarter (US Rockets): low impulse composite formulation which produces
large numbers of sparks.
Hellfire (Vulcan): a high thrust motor which produces a bright red
flame.
Smokey Sam (Vulcan): produces a dark exhaust to aid in tracking.
Silver Streak (Rocketflite/MRED): produces a fine shower of white sparks
during boost (these are actually black powder motors).
White Lightning (Aerotech): medium average thrust engine producing a
bright white flame and distinctive roar.
3.1.7 What's an FAA waiver? Which rocket flights require one?
An FAA waiver is official permission by the Federal Aviation Administra-
tion allowing the launching of rockets exceeding a certain size.
A waiver is required for all rockets weighing more than one pound,
containing more than 160NS total impulse in its engines, having more than
4 total ounces of fuel, or having any motor with more than 2.2 ounces of
fuel, into FAA controlled airspace. This airspace begins at 1200 feet for
many metropolitan areas, but can be as low as 600 feet around airports.
It is NOT legal to fly high power rockets without this waiver. You do not
need a waiver for model rockets weighing less than 1 pound and containing
less than 160NS total impulse. Also, be careful about the 'FAA controlled
airspace' wording. For all practical purposes, it is not legal to fly
rockets greater than 1 pound without a waiver, even if they do not enter
the actual FAA controlled airspace. If you're flying rockets weighing
over 1 pound, get a waiver!!
The Tripoli Rocketry Association publishes information on obtaining an
FAA waiver in their `Members Handbook'. Several high power manufacturers
also publish this information.
The FAA is currently considering a proposal by the NAR to exempt all
models meeting the NAR definition of a model rocket (i.e., 1500 grams...)
from requiring a waiver. This is still just under consideration.
3.1.8 Is high power rocketry legal in every state, if the proper forms are
obtained?
No. Even with an FAA waiver, HPR is NOT legal in every state. Check
with your local fire marshal for requirements/restrictions in your area.
The NAR and Tripoli are actively working to get state restrictions on
model and HPR removed.
3.1.9 I've heard that NAR and Tripoli both have a certification process for
using/launching HPR. How do I get certified? Am I required to be
certified if I want to fly HPR?
First, you have to join either the NAR or Tripoli. In the NAR program,
you first successfully fly a G powered rocket in the presence of two
NAR HPR certified members who witness your flight. You fill in and
mail a certificate (along with $5) to the NAR, which places your name
in its computerized list and mails you a new license stating your new
certification level. You are then qualified to fly H rockets. By
doing the same thing with an H rocket you may qualify to fly I motors,
and so forth. You need to be certified for each new engine type.
You can qualify for multiple NAR HPR levels at a single event if that
event is a sanctioned regional or national NAR launch (such as Regional
Sport Launches, NARAM and the NSL). You may then pay only a
single $5 processing fee. Also, as of August, 1992, the NAR allows
clusters of motors to qualify for a particular impulse level (for
example, you might cluster 2 'F' motors for your 'G' flight, or
cluster 4 G40 motors (480NS total impulse) to get your 'J' certification).
With Tripoli's 'Consumer Confirmation Program', you must successfully
launch and deploy the recovery system (you don't actually have to
recover) an H powered rocket in the presence of an Authorized
Person (who these are is spelled out in the Members Handbook). This is
your 'confirmation flight'. Your consumer card is filled out at the
launch and one part of it is returned to Tripoli. You are then said to
have been 'High Power Certified'.
Both organizations have 'grandfather' clauses to allow 'known HPR flyers'
or members certified by the other organization to be certified without
a confirmation or certification flight. If you are Tripoli certified,
(and an NAR member) you may send in your Consumer Confirmation card to
the NAR (along with $5) and you would become NAR 'K' certified.
Finally, both organizations are continually reviewing their respective
certification processes. The description listed here might differ from
the actual certification process at the time you attempt to certify.
3.1.10 Where do I find out the proper way to use HPR rockets and motors? I'm
familiar with the NAR Model Rocketry Sporting Code. Is there an HPR
equivalent?
Both the NAR and Tripoli have HPR safety codes. The two organizations
are working together to produce a consistent safety code to be presented
to the NFPA. These codes specify minimum launch field sizes, minimum
distance to keep from launchers, etc. The NAR Interim High Power Rocket
Safety Code has been published in Sport Rocketry. The Tripoli safety code
is published in their Members handbook, which is sent to all new Tripoli
members. EVERYONE WANTING TO GET INVOLVED IN HPR IS STRONGLY URGED TO
JOIN ONE OR BOTH OF THESE ORGANIZATIONS. There are legal restrictions
to buying high power motors. Only certified members of 'legally
qualified' organizations may purchase them. If you want to fly high
power you need to be a member of either the NAR or Tripoli.
3.1.11 What are some good kits to build when first getting into high power
rocketry (assuming I have all of the basic model rocketry skills)?
From [email protected] (C. D. Tavares):
From [email protected] ((Rusty Whitman):
NCR Big Brute
From [email protected] (C. D. Tavares):
AAA Penn. Crude
From [email protected]:
I REALLY like the Aerotech line. Easy to build, well constructed,
(Great nylon chutes, through-the-wall-construction, all that good stuff)
and pretty reasonably prices. They're all E-G. ISP has a similar line
(the parent company).
From [email protected] (Jim Cook):
LOC kits are a good introduction into high power - they are strong
(banging it several times for emphasis on the table).
From [email protected] (Buzz McDermott)
If you have never flown anything bigger than an Estes or FSI D
motor, I would recommend building one or more E-G kits before
tackling H power and up. When you go for your NAR or TRA
certification, choose a rocket where G and H motors are the low
end or mid-range power options. Going with a rocket where your
chosen motor is at the high end or above the rockets recommended
power range is more likely to fail by over-stressing the design.
Bigger, slower high power rockets are less stressed and more likely to
succeed. In the case of NAR certification, this gets you a rocket
good for multiple certification levels. I like the following (either
is a good NAR or TRA certification rocket):
MRED (Microbrick) Summit (F-I motors)
LOC Mini Magg (G-I motors)
----------------------------------------
Section 3.2: High Power Construction and Finishing Tips
This section includes tips and suggestions on various topics having to do
with construction and finishing techniques. These have been posted to
r.m.r or mailed to the moderator by way of r.m.r request. Refer to this
same section in Part 2 of the FAQ (Model Rockets) for additional tips
oriented towards model rocketry requirements. Readers are also encouraged
to read the North Coast Rocketry technical reports on HPR construction
and finishing techniques (available from NARTS and other sources). Refer
to section 1.4).
3.2.1 Cutting, Sealing, Attaching Fins
From: [email protected] (David M.V. Utidjian):
To fill the grain in balsa fins and fill in the spirals in body tubes
use epoxy. I use HOBBYPOXY "Smooth 'n' Easy" Epoxy finishing resin.
For fins it does the trick in one coat... and sands easily... and
adds strength to the fins. I use those disposable brushes with the
metal handles and brush on a single coat after a preliminary sanding.
I then use auto body primer filler in gray and red-brown from spray
cans for the entire model. This gives very thin and even coats. I
alternate the colors of the coats to show where the low and high spots
are. My last sanding before paint is done with 400 grit wet/dry paper
and I do this wet... being careful not to get any inside the body tube.
[Another good coating-type epoxy is PIC 'Coating Poxy'...Buzz]
[NOTE: This is not for kids or the inexperienced!! This technique is
used in HPR where the added weight is not a penalty: Buzz]
From Bob Turner (NAR member, not on net):
Bob Turner (the DARS NAR section advisor) suggests using alcohol in
smoothing 'coating' type epoxies. The PIC 'Coating Poxy' instructions
suggest using your fingers to 'burnish' any surfaces (i.e., fins) filled
with the coating poxy. Bob suggests using a VERY soft cloth which has
been dipped in alcohol to rub the fins after about 30 minutes (or
whenever the epoxy starts to set and is just slightly sticky to the
touch). [I followed Bob's suggestion and got MUCH smoother fins over
the hand/finger burnishing method...Buzz]
From: [email protected] (Jack Hagerty):
When sanding fins, or any other balsa part that you want to be all
uniform, stack the parts together, even them up the best you can
(you'll be surprised at how uneven those die-cut pieces are!) on
the root edge and drive a couple of straight pins through them to
hold the stack in registration while sanding. For larger fins,
anything over about 2 sq in, use three pins. I find that the pins
that come in shirts are just about the right size. The small holes
that are left when you remove the pins are easily filled during the
sealing/filling step.
From: [email protected] (Bob Kaplow)
I've found two handy tools for sanding big rockets. 3M makes these
sponge-like sanding pads. They are great for conforming to the
curves of tubes, nose cones, fillets, etc., and make quick work of
fillers. The second is a palm sander, just like Norm uses on TV. Big
rockets call for heavy duty solutions. Save the belt sander for
airfoiling the fins during construction.
Condensed thread on filleting fins; many contributors:
First, ALWAYS fillet high power fin joints, even fins mounted TTW to
the motor mount. This will add strength and improve the aerodynamics
of the model. The suggestions for filleting material include:
* 5 - 30 minute thick epoxies
* 30 minute (or longer) thin epoxy mixed with micro-balloons
until it has a thick, paste-like consistency; let it thicken
some prior to using it
* SIG Epoxilite (warning: this got very mixed reviews)
Always keep a bottle of rubbing alcohol handy when working with epoxy.
Dip your finger in the alcohol and run it along the fillet to smooth
out the bumps. It was mentioned that a pure epoxy 'topcoat' was
necessary on top of the epoxy/micro balloon mixture, although using
an alcohol-soaked finger to smooth the micro-balloons might eliminate
the topcoat requirement.
Use 30 minute epoxy with microballoons added. Let it sit for a few
minutes in the pot so it thickens, and then apply it. The microballoons
make it much less runny, so you don't have to keep watching the fillet
to make sure it's not dripping or running around the edges. Also do one
side of two fins at a time:
\ /
\ / f = fillet, ^ = really bad version of body tube
\f f/ / and \ = fins
^^^^^^
3.2.2 High Power Motor Hooks
From: [email protected] (Bill Nelson)
I make a clip similar to the ones used on model rockets - however, I do
not pierce the motor mount tube - I place the front end of the retainer
over the front of the tube. It is epoxied/taped in place, just like with
a model rocket. I do not rely on spring pressure to hold the clip over
the end of the engine. I use several turns of strapping tape - wrapped
around the engine or motor mount and the retainer clip. So far, I have
never had a problem with an ejected engine.
From: [email protected] (Jim Cook)
Some folks at NARAM 33 suggested drilling a small hole in the side of
the flange of the rear nozzle retaining ring [of an ISP reloadable motor
casing] to tie the casing to the model. Some might claim this to be
"modification of rocket motors not approved by the mfg." I had though I
heard Aerotech was going to start doing this themselves, but I haven't
seen anything yet.
From: [email protected] (Neil Pyke)
I've built #8-32 "t-nuts" into my last couple of rockets and then made
sheet metal brackets to hold the motor in. I drill two holes, 180
degrees apart, in the aft centering ring and then press and glue the
t-nut into the hole. The screw holds the bracket to the centering ring
and I bend the bracket so it hooks over the end of the motor. The t-nut
works great but I've made my brackets too wimpy. Those that saw
me wandering around just past the flight line at LDRS a couple weeks
ago, looking for my ejected motor, will know that I have not perfected
my application of this design.
From: [email protected] (A. Roger Wilfong)
I've used a similar technique with t-nuts and had no problems - yet.
I've also tried a coarse thread sheet metal type screw (I'm not sure
what they're really called - the threading is about twice as coarse as
a regular sheet metal screw) screwed into the rear centering ring at
three locations. The centering ring needs to be plywood and you need to
carefully drill the correct sized pilot hole for the screw. After
'tapping' the screw into the hole, I took it out and ran a small amount
of thin CA into the hole for reinforcement - let the CA set before you
put the screw back in the hole or you won't get it out again. This has
worked on RMS-29 and while it is not as strong as the T-nuts, so far it
has been more reliable than masking tape.
From: [email protected] (robert.e.wiersbe)
[Bob] Kaplow uses special metal hooks that he bolts to the bottom
centering ring. The hooks look like this:
|\
| \
| \
| \
|
|
|
|
_______|
He epoxies the nut to the inside of the centering ring, and the bolts
need an allen wrench to tighten (you could use any kind). He also has
different length hooks for different size motors. I think the hooks are
made out of brass.
3.2.3 Custom Decals for High Power Rockets
The techniques described here could also be used for model rockets. The
decals made this way tend to be large and `thick', so this info has been
included in the High Power section.
From [email protected] (Tim Harincar):
As a computer graphics person, I have done quite a bit of experimenting
with laser printers and making my own rocket art. I mostly stick with
clear sticky-back type stocks, they are the cheapest and most available.
I use Fasson brand, and I think its 1.5 or 2 mil. thick. It works good for
large models but is a little thick for small scale stuff. It curls right
out of the laser while it cools. Don't worry, though. It doesn't distort.
This stuff is typically available at most quick print shops. Typically
its called Crack 'N Peel.
Toner chips very easily off of the smooth finish, so be careful and as
soon as you can, spray on an over coat of clear flat enamel or lacquer.
I tape the sheet down to cardboard then spray, Leave it for a day or so.
This also makes it lie flat.
I know that blank water transfer stock is available, but its about $3 for
an 8.5 x 11 sheet. Use same method as above to preserve the image. This
is usually available at model railroad shops.
I have never seen the dry-transfer stuff, but I know its pretty popular
with the railroad folks. (that is, the pre-printed stuff).
One other option that I have wanted to try is the heat-transfer colors.
Once you have a laser image, you lay a piece of special colored film
over the image and heat either with an iron or re-run the sheet through
the laser and let the fuser do the work. The color then attaches to the
toner.
Most of these colors are metallic, but there are some standard, non-
metallic colors as well. Letraset was the first company to market
the color transfer stuff.
3.2.4 Getting Paint to Stick to LOC and Aerotech Nose Cones
From: [email protected] (Roger Wilfong)
I have had success painting nose cones from both companies using Krylon
and Walmart paints. The technique I use is to wash the nose cone with
a Brillo pad followed by a thorough rinse. Fill the mold parting mark
with auto body putty and sand it smooth. I next use a coat of primer
(I've use Krylon's grey sandable, Walmart's grey and Black Baron - the
Black Baron was the best, but also the most expensive and took the
longest to cure). This is followed by a light sanding and another
coat of primer, followed by sanding. After the primer cures (a week, if
I'm in the mood to paint, a year if I'm not), paint it with some paint
that's compatible with the primer.
This technique works fine on the LOC nose cones, the only problem I've
had with the Aerotech nose cones is that the very tip tends to get
chipped off.
I have a LOC PNC-3.00 that has lawn darted into hard ground twice. The
original paint is scratched, but it shows no signs of flaking off.
From: [email protected] (Greg Smith)
I rough up the surface of plastic nose cones with 60 grit paper, then
use my basic epoxy painting regimen as I've described earlier. After
the first coat of primer, the surface is *really* fuzzy; the paint
reinforces and thickens all the little plastic strands that are raised
by the sandpaper, and the surface feels like rough concrete. But a
little sanding knocks off most of it, and after the third primer coat or
so, the surface is as smooth as anything else on the model. I don't
believe there are any chemical changes taking place in the polyethylene
(and yes, I'm quite sure that's the plastic used since the same
facilities are used to blow-mold nose cones as for all those plastic
bottles in your pantry, and they're all PE), which is normally quite
impervious to everyday solvents. Rather, you're just creating a rough
surface that the paint can fill in and grab onto, then sanding off the
worst of the fuzzies with much finer paper later, after the paint has
made them stiff enough to sand.
The only time I've ever damaged the finish on one of these nose cones
happened when a model fell off the workbench and onto the concrete floor
in my basement, which chipped the tip of the cone a bit. Normal flying
(including one or two landings on concrete) hasn't affected them at all.
3.2.5 Eliminating 'zippered' body tubes.
Many of us have recovered our rockets only to find that shock line has
slit ('zippered') the body tube. This happens most often when a very
thin shock line is used or when the rocket is traveling very fast when the
tubes separate. The following suggestions have been offered to prevent
this from happening:
From: [email protected] (Stu Barrett)
I built a LOC Caliber a year or so ago. I installed a LOC ejection
baffel at the top of the motor mount tube and that worked great.
However, I'm in the process of enhancing my model so that it uses the
"anti-zipper" technique that is described in the Mar/Apr [1993] issue
of HPRM. It combines a fool proof mechanism to eliminate the dredded
"zipper effect" and also has a nice effect that no wadding is needed.
3.2.6 Recovery Wadding for High Power Rockets
From: [email protected] (Jack Hagerty)
Just go down to your local building supply store and get a bale of
cellulose wall insulation. This is just shredded newspaper treated in
the same fire supressant [as Estes recovery wadding]. A $5 bag will give
you enough wadding to last years!
From: [email protected] (J A Stephen Viggiano)
I use cellulose insulation. I bought a "lifetime supply" (a bale) at
a home improvement, DIY, place. Just fluff it in (it comes in compressed
form) and stuff a handfull or two in the tube.
In order to avoid fallout, you might want to put the engine in
*before* the wadding, or, for smaller rockets, a sheet or two of regular
wadding underneath the fluffy stuff.
Wayne Anthony uses cabbage leaves (you get more leaves per head [than
lettuce], and they seem to be a little tougher than lettuce), and I've
heard of people using grass.
From: [email protected] (Buzz McDermott)
I use acoustic speaker insulation. I costs #3 - $5 per bag at Radio
Shack. It's reusable, and one bag generally lasts me for dozens of
flights.
-----------------------------------------
Section 3.3: Ignition and Launch System Tips
The following are topics dealing with HPR that have been asked and/or discussed
in r.m.r postings. North Coast Rocketry has a series of technical reports,
several of which deal with HPR ignition, clustering and staging (especially
with composite motors). These are available from NARTS and other sources
(refer to Section 1.4).
3.3.1 Copperhead, squib, electric match, thermalite, flash bulb. What are
all these types of igniters, how much current do they require, and
when are they used?
Copperhead see 3.3.2 used to ignite single composite motors; not
good for clustering. They will light most
black powder motors. Requires strong 12V
current source.
Electric Match a type of electric igniter requiring VERY
little current to ignite. As little as 20ma
of current will set them off. Used for
igniting high power motors and motor
clusters.
Thermalite a type of fuse used extensively in pyrotech-
nic applications. May be ignited by nichrome
wire or flash bulb. Plain thermalite ignited
by nichrome wire is often used in black
powder clusters.
Flashbulb/thermalite some types of camera flashbulbs ignite
with very little current (typically as
little as 50ma) and burn very hot. These
are used to ignite a piece of thermalite fuse
running into the motor. Used for igniting
high power motors and all forms of clusters.
Magnelite medium to high current requirements. Sold
by Rocketflite to ignite Silver Streak
motors. Work well to ignite single high
power motors. These are magnesium tipped
igniters that burn at a very high
temperature.
In general, almost any current source from a 1.5V 'C' battery up might ignite
a flash bulb or electric match. For the other igniters, a 12V system capable
of delivering several amps of current to the igniter is required.
3.3.2 How do those 'Copperhead' igniters work? They only have one wire?
Copperhead igniters are actually two strips of copper wire with a
thin mylar insulating layer between them. To use these with regular
alligator clips you need to use masking tape to insulate opposite sides
of the igniter from each clip.
'Thin' (side) view of copperhead igniter:
| |
|______| < Motor with Copperhead inserted
||
Masking > ||
tape > ||
||
||< Masking
||< tape
||
Attach one alligator clip at each masking tape point, so that each clip
only makes contact with one (opposite) side of the igniter.
The Quest 'Tiger Tail' igniters are the same type of igniters as
Copperheads. They come with a special 'wrapper' with openings for
alligator clips.
NOTE: Copperhead igniters require a 12 volt ignition system.
3.3.3 Do you have any specific suggestions or tips for an ignition power
sources? Can I use my old Estes ignition system with composite models?
The Estes, Quest and other model rocket launch systems are fine for most
model rockets. If you do a lot of flying there have been some suggestions
posted to the net. If you are trying to launch cluster models with solar
igniters you will need more 'juice' than 4 AA batteries can provide. This
is also true of clustered Copperhead type igniters.
From: [email protected] (C. D. Tavares)
A motorcycle gel cell, however, will last a long, long time.
Our club uses a gel-cell the size of three VHS tapes to launch 120
rockets over six hours, and it comes home at about 80% charge.
From: [email protected] (Bill Nelson)
I bought a 12 volt motorcycle battery for about $20. I only need to
recharge it 3 or 4 times a year. I have adapted all my launch
controllers to allow usage of the battery.
3.3.4 WARNING: BE VERY CAREFUL USING ANY IGNITION SYSTEM WITH 'FLASHBULB' TYPE
IGNITERS.
Many (most?) launch ignition systems are not 'flashbulb safe'. Just
arming the circuit (i.e., doing a continuity check) will fire the
flashbulbs and ignite the motor. If you plan to use flashbulb ignition
often, you might consider investing in a 'flashbulb safe' ignition system.
From [email protected] (Jim Cook):
A lot of launch systems use a light bulb to do a continuity check.
The current through the light bulb is enough to set off flash bulbs
(They require only milliamps to fire).
3.3.5 THE IGNITION OF ROCKETS BY OTHER THAN ELECTRICAL MEANS IS BANNED BY BOTH
THE NAR AND TRIPOLI SAFETY CODES AND SHOULD NOT BE USED.
There was a fairly lengthy discussion in r.m.r about the use of hand-lit
fuse to launch rockets. Although there was an advocate of this method the
consensus opinion of the net was that the NAR and Tripoli safety codes
made good sense, hand-lit fuse igniters were unsafe, and electrical
ignition (even if igniting fuse by electrical means) should be used for
all activities. Hand-lit fuses are also against most state laws.
3.3.6 What is thermalite fuse and how is it involved in igniting rocket
motors?
Thermalite is a type of fuse that has been used in the pyrotechnics
industry for a number of years. It comes in three burn rates, identi-
flyable by the color of the fuse wrapping:
Color Type Burn Rate Usage
Pink Slow 20 sec/foot Flashbulb ignition
Green Medium 10/sec/foot Ignition enhancer
White Fast 5 sec/foot Not used much in rocketry
The burn rates are approximate and vary with humidity, temperature, age
of fuse, etc. The numbers also correspond to burn rates of exposed
thermalite. When enclosed in heat-shrink or teflon tubing, all three
types burn at an equally fast rate. A typical usage for thermalite is
in a flash bulb igniter:
| < 1/2 to 3/4 inch of thermalite exposed out
| < end of sheathing
|||
||| < thermalite fuse in teflon or heat-shrink
||| < tubing (fuse should *just* fit into tubing)
|||
|||
+ |
+ +| < 1/2 to 3/4 inch thermalite exposed out end
flash bulb > + +| < of sheathing and taped to flash bub using
+ + < CELLOPHANE tape (NOT masking tape).
+
/ \
/ \ < electrical leads to ignition system
The fuse is sheathed except for about 3/4" at each end. The sheathed fuse
is inserted into the motor and must be long enough for the exposed end to
go all the way up through the core and out the bottom of the motor.
Composite motors are ignited at the top of the core (nearest the delay
charge). The sheathing on the fuse is to keep from igniting the motor
anywhere but the correct location. The other end of the fuse is tape to
a hot-burning flash bulb. The flash is then attached to the ignition
system and ignited in the normal fashion. This lights the thermalite
fuse, which then ignites the motor.
This is the ignition method of choice for clustered composite motors (in
any number above 1) and large clusters of black powder motors.
WARNING: Flash bulbs require VERY LITTLE current to set them off. Read
the warnings in 3.3.4, above.
3.3.7 How do you ignite second stage composite motors? Can I use a black
powder booster for the first stage to ignite the second (as I do
with multi-state A-D rockets)?
Upper stages of composite powered models may be ignited by
electrical means or thermalite fuse. North Coast Rocketry has
a Technical Report covering this subject. Excellent articles have
also appeared in Sport Rocktetry/AmSpam and HPRM magazines.
You cannot use a black powder booster to ignite a composite upper
stage. The gasses from a BP booster will not properly ignite a
composite. There are composite boosters on the market. These boosters
are all 'plugged' and so cannot ignite any type of upper stage motor.
Composite motors are mostly 'core burners' with the core running the
entire length of the fuel grain. A composite core burner set up like a
BP booster would ignite a BP upper stage too soon.
There are several issues involved in igniting upper stage composite
motors. (1) A timing method must be provided to delay ignition until
the appropriate time, (2) power source for the igniter is required and (3)
the igniter itself must be provided and be capable of igniting high power
motors. Whatever method of ignition is chosen, all 3 criteria must be
met.
Timing Methods ....
Several methods of timing have been developed and used. The earliest and
cheapest timing method is to use a length of unsheathed thermalite fuse.
The fuse is typically ignited by the exhaust from the first stage motor.
The fuse is long enough to allow for the first stage motor burn time and
any desired post-burnout coast. The last portion of the fuse is sheathed
and inserted into the upper stage motor to act as the igniter. The problem
with this method is that not all thermalite burns at the same rate. Also,
the same batch of thermalite will burn at different rates depending on the
altitude, temperature and humidity at the time and place of launch.
Mercury switches were another early method of 'timing' upper stage
ignition. A mercury switch is a small glass bulb with an enclosed drop
of mercury. Two wires run out the top of the bulb. When the switch
is tilted or decelerated the mercury rolls forward to make contact with
the two wires and close the circuit. This results in a closed circuit when
the booster motor stops firing and the rocket begins to decelerate. The
ignition circuit would be set up so that power is provided to the igniter
when the mercury switch closes. EXTREME care must be exercised when using
mercury switches. Titling the rocket closes the switch, so provisions for
disarming the circuit must be included. After the rocket is placed on the
pad and the circuit armed, any sudden movement of the rocket could set of
the second stage.
The next generation of upper stage ignition systems were based on
electronic timers of various types, both analog and digital. The timer
was set for the appropriate time (first stage burn time + inter-stage
delay, if any). A contact switch, usually kept open by the launch rod,
would often be used to initiate the timer. As the rocket leaves the
launch rod the timer is started. After the preset time interval the timer
closes the circuit allowing power to the igniter. Again, great care must
be taken with these devices. If the contact switch is allowed to close
prior to the rocket lifting off the 2nd stage could ignite while the
rocket is still on the pad and there are people around.
Another form of early timing device was based on photo-electric sensors.
A sensor would be placed in a position such that light could get through
the booster motor tube after all of the fuel was spent. When the sensor
detects light the power circuit is closed.
Remote control has been used to initiate firing sequence in mutli-stage
rockets. This method has the advantage that the 2nd stage isn't ignited
unless a human being takes positive action, while the rocket is in the air.
It also requires an R/C transmitter, receiver, etc.
Some newer devices are out based on acceleration detection. These are
sometimes combined with timers. Liftoff acceleration is detected. This
either starts a timer or enables a deceleration sensor. At the specified
time interval, or when deceleration is detected, the power circuit is
closed.
Power Sources ...
Two forms of electric power are commonly used, capacitors and batteries.
A capacitor is typically charged from an external source just before
liftoff. The timing device then closes the circuit at the proper time
and the capacitor discharges, firing the igniter. One disadvantage of
this method is that the capacitor charge slowly bleeds off, meaning that
the rocket may not sit on the pad a long time after preping and still
reliably ignite the upper stage(s).
All forms of small batteries have been used, depending on the power
requirements. Common batteries for igniting a single, low power igniter
are 9V transistor and 12V alkaline lighter batteries.
Timed thermalite fuse ignited by exhaust from the booster requires no
power.
Igniters ...
Multi-stage rockets generally have a limited current source for igniting
upper stages, so very low power igniters are used. Two common igeiters
are electric matches and flash bulb/thermalite fuse. Both of these
igniters are described elsewhere in this document.
Readers are encouraged to review the NCR technical reports and rocketry
magazine articles on composite multi-staging.
3.3.8 Other Ignition Tips:
From: [email protected] (Doug Wade)
[concerning adapting launch controllers to 12V car batteries ...]
Speaking of which, I took my Aerotech launch setup, lopped off the
igniter attachment, and the place where it attaches to the battery, put
amp plugs on either end, put a plug on the battery, and made some
alligator clips in various configurations for launching Estes stuff.
This means that I can switch batteries and igniter style in basically
no time at all. It's not a lot of work, and it makes life easier. If
you have the urge to do this kind of thing, make sure that you get
plugs that can handle it. A 12V motorcycle battery (Mine was about
$40 but it's pretty nice) can put out something like 15A for a short
period of time...
----------------------------------------
Section 3.4: R/C Rocket Glider Construction Tips
The D-G powered R/C rocket gliders now available are presenting some new
problems to ModRoc'ers, who are more used to making balsa wings, fins, etc.,
then built-up wings. Here is a set of tips submitted by Iskandar Taib, a long
time model plane enthusiast, and others. There is an excellent FAQ in the
rec.models,rc news group. It includes very good information on how to get
started into R/C flying, tips on where to buy equipment, etc.
3.4.1 Construction Reviews
Aerotech Phoenix: August, 1992, "Model Builder Magazine"
Estes Astroblaster: September, 1992, "Model Builder Magazine"
Both articles are written from the perspective of experienced R/C
aircraft modelers. They both contain good construction and flying
tips.
3.4.2 I'm building the 'XXX' R/C Rocket Glider and it uses foam core wings.
Are there any things I should know about working with foam?
The first thing to know is that certain paints and glues dissolve
foam. Both the stuff made out of white beads (referred to as "bead-
board") and the blue (Dow Styrofoam (tm) ) or pink (DuPont Foamular)
extruded foam will behave in the same way. Once sheeted a foam wing
can sometimes be finished in a paint that ordinarily dissolves foam
if one is careful about not putting too much on at a time. Here is
a list of what will dissolve styrofoam and what won't:
Will dissolve foam:
Nitrate and butyrate dope
Ambroid
"Model Airplane Cement" (you know what I mean)
Polyester resin (sold as "fiberglass resin" at K-Mart)
Thick and thin cyanoacrylates (excepting UFO)
Paints from spray cans
Dope and paint thinners
Gasoline
Dope thinner, acetone
Solvent-based contact cements
Won't dissolve foam:
Polyurethane paints and varnishes (inc. Rustoleum)
White or aliphatic glues (Elmer's, Titebond)
Epoxies
Ethanol or methanol (sometimes used to thin epoxies)
UFO superglues
Water-based contact cements (eg. Southern Sorghum)
Follow the instructions provided and you won't go wrong. Most struc-
tural building is done with white glue and epoxy is used for sheeting
the wing and/or putting down fiberglass, graphite or kevlar cloth.
3.4.3 Any tips for sheeting the wings on my Aerotech Phoenix?
The Phoenix kit requires that you sheet the wing with balsa using epoxy
as the glue. Aerotech also recommends that you vacuum-bag the wing for
the lightest wings possible. Vacuum bagging is a fairly new technique
that I will describe later.
The process involves preparing the wing skins, mixing the epoxy (need-
less to say, the 24 hour laminating variety, spreading it on the skins
with a squeegee, scraping most of it off, applying the skins to the
core, then assembling everything together in the core beds (the pieces
left over after the core is cut), and putting lots of weight on top
of the whole thing. Oh yeah.. the wing has to be kept straight so
you'd have to do this on a very flat surface. The more pressure you
can put on this, the better glue joint you'll have, and the less glue
you'll have to use, which makes for a lighter wing.
VACUUM BAGGING
This is where the vacuum bagging comes in. The core bed/sheeting/core
assembly is put into a large bag which is sealed on all sides. Then the
air is pumped out of the bag. This is supposedly the equivalent of pi-
ling hundreds of pounds of weights on the core. In fact they tell you
to limit the vacuum to so many inches Hg otherwise the cores will crush.
Vacuum bagging is also useful if you are going to lay up fiberglass
on top of the balsa wing skins. Fiberglass cloth is now available in
very light weights and people often use it in lieu of a covering film
or fabric.
The way it used to be done was that the cloth was laid down and a thin-
ned (with alcohol) epoxy brushed into it. Then excess epoxy was removed
using rolls of toilet paper (discarding layers as they became saturated).
With vacuum bagging one lays down a sheet of drafting mylar on top of
the wet glass cloth, then puts the assembly in core beds. The assembly
is then vacuum-bagged. After curing the mylar sheets are removed and
you end up with a glass-like finish that is extremely light since all
excess epoxy has been squeezed out. This also obviates the need for
lots of the filling and sanding usually necessary before painting.
3.4.4 How about help with my Estes Astroblaster wings?
The Astro Blaster kit uses contact cement for sheeting the wings. The
cement is of the water based variety. It is applied to both skin and core
and is allowed to dry. After this has occurred, the skins and core can
then be brought together. This is a little trickier, since you don't get
a second chance.. Once the core touches the skin you can't separate them
without breaking something. The skins are just 1/32" thick so one
has to be gentle with them.
3.4.5 How do you repair damaged foam wings?
Repairing foam is fairly easy. One simply hacks out the damaged piece,
glues in a block of foam and carves and sands to shape. Carving is best
done with a brand new utility knife (the kind that has break-off points)
and sanding can be done with a sanding block. Sheeting is replaced in
the same manner - cut out the damaged piece and glue on a replacement.
A little glass cloth or carbon fiber matte over the break helps too.
3.4.6 Some more uses of foam in rocketry...
Foam is interesting stuff to play with. You can cut wing cores using a
hot wire and 1/16" ply or formica templates. Parts for rockets can be
made by simple carving and sanding.
Even more interesting is making lightweight wings and other parts using
foam, silkspan and thinned white glue. Someone called Ron St. Jean built
lots of competition free flight models in this manner. The silkspan is
applied wet over the foam, and thinned white glue is brushed on. When
the silkspan dries it shrinks, and the result is an incredibly strong and
stiff structures. One could conceivably use this method for nose cones
or complex scale models. In England, foam and brown wrapping paper is
used for complex ducted fan models (someone actually flies a seven foot
long scale Concorde constructed like this).
If one uses heavier paper (eg. grocery sacks) perhaps one can dissolve
the foam once the white glue is set (use acetone or dope thinner for
this). For rockets imagine something shaped like a V2 made like this.
Once the foam was dissolved you'd end up with a light weight craft paper
tube of the proper shape, boat tail and all.
3.4.7 I need to cut the piano wire control rods. Bolt cutters don't work well,
as the metal is too hard. Any ideas?
From: [email protected] (Iskandar Taib)
What you want to do is get your hands on a reinforced cutting wheel
like the House of Balsa Tuf-Grind. The Dremel ones tend to shatter and
throw pieces at high speed. If you use them harden them with thin
superglue.
|
| 33.13 | FAQ Part 4 of 5 | VERGA::KLAES | Quo vadimus? | Wed Mar 02 1994 12:37 | 1069 |
| Article: 15952
Newsgroups: rec.models.rockets
From: [email protected] (Buzz McDermott)
Subject: (FAQ) Frequently Asked Questions - Part 4 of 5
Organization: NETCOM On-line Communication Services (408 241-9760 guest)
Date: Wed, 2 Mar 1994 04:34:50 GMT
Rec.Models.Rockets FAQ (Frequently Asked Questions): Part 4 of 5
Last Modified: 14 January 1993
*** PART 4: Payloads
[Note: This part of the FAQ is maintained by Jack Hagerty ([email protected])
Any additions or corrections should be sent to that address]
Updates
-------------
Apr '93: Minor updates to Astrocam "tips" section and recorded video section.
Added the "Rosenfield Hack" to Cineroc section.
May '93: Added more "ejecting" payload references at the very end.
July '93: Added references to articles in HPRM on homebrew still cameras and a
transmit video system.
Nov '93: More updates on camera projects, Added "Guidance System" Section.
>>>WHOLE NEW SECTION!<<<
Jan '93: Minor addition to camera introduction
-------------
Introduction - Flying sport rockets is fun. Flying competition rockets can
be exciting in the heat of battle. Scale models (my favorite) can be as much
of a challenge to research and build as they are to fly. But if you want to
do something "real" with your rocket, you've got to fly a payload. This also
provides you with a good response to the perpetual question from the great
unwashed masses when they ask "so, what's it do?"
I've organized this section into the following topics (suggestions for
expansion into other topics gladly accepted):
4.1 Camera Payloads
4.1.1 Commercial Cameras
4.1.2 Homebrew cameras
4.1.3 Video
4.2 Data Gathering Payloads
4.2.1 Transmitter
4.2.2 Data logging
4.2.3 Sample collection
4.3 Bio-payloads
4.4 Guidance Systems
4.5 Novelty Payloads
4.5.1 Contest payloads
4.5.2 Ejecting payloads
----------------------------
4.1 Camera Payloads
Cameras are the most often flown payloads (after eggs and bugs :-) because
they hit us where we live. No other payload lets us see the flight from our
rocket's point of view. The intensity of interest in camera payloads can be
seen by how early they were flown: Goddard flew them, the VfR (the German
rocket society which gave Von Braun his start) flew them and, of course,
dozens of post war sounding rockets carried camera payloads. In fact, the
very first operational (as opposed to experimental) rocket system was Alfred
Maul's photoreconnaissance rocket built for the German Army which was used
from 1912 until airplanes became more reliable.
Some of the products and techniques that have been tried and/or are still
available are:
4.1.1 Commercial Cameras (chronological order):
Camroc - The first purpose-designed rocket camera. Designed by Estes and
sold from 1965 to 1974. A marvel of simplicity, it was patterned after
several homebrew cameras of the early '60s (see 4.1.2). It was simply a
cylindrical body that held the film topped by a hemispherical nose that
was flattened off to accept the optical window which the forward facing
lens looked through. One shot per flight on "Astropan 400" (Kodak Tri-X)
cut into a 1 1/2" dia. round negative. Easy to process at home. The film
had to be push processed to 1200 ASA (officially, though most home
developers went to 1600). Extremely valuable on the collector market.
[Note: Don't write me asking how much your old Camroc's worth. Bob
Sanford ([email protected]) tracks those sorts of things - JH]
Greg Smith ([email protected]) describes some of the various hacks
of the Camroc: "At one time there were quite a few homebrew modifications to
the Camroc floating around. Most popular was substituting a 3-element glass
lens from Edmund Scientific for the standard plastic lens; it gave much
sharper and better color-corrected results. I have also seen a wide-angle
variation with yet another Edmund lens that required cutting the forward body
section of the Camroc down to a much shorter length. As someone pointed out
at the time, the Camroc lens was a short telephoto relative to its film
format. It doesn't make sense to send a rocket up as high as possible and
then use a telephoto lens to get a SMALLER angle of view; it's a wide angle
you really want, so you can get more in the picture from a lower, easier-to-
aim flight with a smaller motor and less risk of losing the camera. Several
people flew color slide film in the Camroc, but high-speed color films were
pretty terrible at the time; the ASA 1600 print films available today would
probably work very well in it."
Cineroc - Estes' second foray into camera payloads, the Cineroc was *much*
more sophisticated than the Camroc. This was a full bore 8mm movie camera
crammed into a package not much bigger than it's predecessor (although more
aerodynamic). Introduced with much fanfare in 1969, it lasted only 5 years
before its plug was pulled in 1974. The lens looked aft via a hooded mirror
and it shot ~15 sec worth of flight time at 2X speed (30 sec projection
time). At least that's what the spec says. In reality, most Cinerocs ran in
the 18 - 20 fps range which is more-or-less normal speed. The film was a
Kodak ASA 160 instrumentation film on a polyester base which was probably
adopted because it was the only daylight-balanced Super 8 film available.
The Cineroc used a custom film cartridge meaning that you either used the
Estes processing service or went to a custom lab. It could be developed
at home using a Kodak E-4 developing kit, but this was *much* more trouble
than most modelers would want to go.
Gary Rosenfield, now president of Aerotech/ISP, made a name for himself
by coming up with a significant hack on the Cineroc that both reduced its
diameter and increased the film capacity. As detailed (somewhat sketchily)
in the V 14, N 1 (July 1974) issue of the _Model Rocket News_, Gary took
the basic guts of the camera (lens/film gate/geneva transport plus motor
and batteries) and put them in a BT-55 tube with the mirror hood outside
as usual. He extended the tube fore and aft enough to hold 50' of film (a
full cassette worth) in random storage, i.e. no spools. The film simply ran
from one compartment, through the gate and into the other compartment.
While this made the system much more difficult to reload in the field, you
could now have the film developed anywhere, provided you bothered to
rewind it back into the standard cassette afterwards. The photo of "Wild
Man Rosenfield" that accompanies the article is probably suitable for
blackmail :-)
The official reason for its early demise, still lamented to this day, was
that the small electric motor it used went out of production. However,
in a conversation with Mike Dorffler (the designer) he revealed that the
product was killed by a combination of events that occurred over a very
short (2 month) period in early '74: the motor went out of production,
Eveready stopped making the tiny "N" batteries, Kodak changed the formula
of the film which couldn't be accommodated by the custom lab doing their
processing and, the coup de' gras, a technician dropped the mold for
making the custom lens.
Some Cinerocs are still flown today nearly 20 years later. The size "N"
alkaline batteries, much better than the original carbon-zinc ones that
Estes supplied, are widely available now; and the new film stock (which
is available off the shelf, not special order like the one Estes originally
chose) is sharper and less grainy than the old stuff. Both of these
actually make for easier and better Cineroc results today than when it was
first introduced. You do still need a custom film lab to deal with the
nonstandard lengths of 8mm film, however.
Astrocam 110 - Another Estes product and something of a combination of the
previous two. Reverting to the still format, the Astrocam was designed
around a stock 110 cartridge. It took multiple shots per roll of 400 speed
color print film, but still only one frame per flight. The lens looked out
through a hooded mirror (like the Cineroc) but this time looking forward
(like the Camroc). Image quality was marginal due to the plastic lens and
small format, but the film can be developed anywhere (although the prints are
reversed). A very long lived product, it lasted from it's 1979 introduction
until early 1992 when, for reasons known only to themselves, Estes canceled
it. Public demand was great enough that they re-introduced an "improved"
version in early 1993. Said improvements consisted of a better lens for a
sharper image, a one stop increase in aperture (so it can use the much more
available 200 speed film) and pre-assembly of the lens and sprocket. Perhaps
the biggest improvement of all was that they dropped the price by $10 :-)
The Astrocam is the source of continual threads on r.m.r. so the following
is a distillation of nearly half a megabyte worth of Astrocam discussions
I've archived:
GENERAL TIPS
Jim Cook ([email protected]):
Some observations from myself and C.D.Tavares:
* The film is quite grainy, hence a lot of people move on to 35mm cameras.
* Underexposure is a problem - the pictures are lousy if you launch in
anything other than bright sun. Of course, there's also the usual problem
of forgetting to open the safety shutter before launch.
* Overexposure is a problem several ways:
- The shutter cord can get tangled in the shroud lines, taking multiple
exposures or one long exposure.
- A hard impact can take another shot. At the least, landing impact will
close the safety shutter making you wonder if you forgot to open it
before launch.
- Problems with sun and heat on the pad make some folks drape it with
aluminum foil until final countdown.
- Adjustments on the pad are always a source of causing the shutter
to go off on the pad.
* Chris suggests advancing the film before take off and advancing it after
landing. Yes, it wastes film, but you tend to not use all the shots anyway.
I believe that Kodak only makes 24 shot rolls of ASA 400 110 size film.
SOME THOUGHTS ON FILM
John Viggiano ([email protected]):
Modern C-41 stocks have a 2-step under / 3-step over exposure latitude. The
material has so low a contrast that little information is lost; the effect
is primarily a density shift which can be removed during printing.
Jack Hagerty ([email protected]):
K-Mart 200 speed print film (which is made by 3M, and sold under many
different "house" brands) makes an acceptable medium. It's cheap, comes in
12 exposure rolls, and has enough latitude to give acceptable exposure.
ENGINE COMBOS
Jim Cook ([email protected]):
Given a well constructed Astrocam, a C6-7 will produce a good shot.
However, an Estes D12-7 will produce a horizon shot or blurry shot as it
is still in motion (this was reported in the Model Rocketeer about 10 years
ago). A little weight will cure this without negating the effect of the D
motor. I've also used AeroTech D21-10 or E25-10 can work well, though I
wonder if a 10 second delay tends to produce horizon shots with an E-powered
launch. Dan Wolman tried an F-based launch which resulted in a blurry image
(again, probably too short a delay), so he tried an F25-10 and lost it to
wind/thermals.
Harry C. Pulley ([email protected]):
With C6-7 engines, I have found that vertical flights range from 550-650 ft
in altitude. For horizon shots with C6-5 engines, the altitude was a little
better (photo taken earlier in descent) maybe 600-700 feet.
Jack Hagerty ([email protected]) [talking about small field flying]:
Estes B6-4's give horizon shots
Quest B6-4's give sky shots
Estes B4-6's give ground shots from ~30' up (real heart stoppers!)
Estes B8-5's give reasonable ground shots
Bob Wiersbe ([email protected]):
A B6-4 will work, but it's hit or miss whether you'll get a ground or
sky shot. D21-10's are superb, though expensive. A C6-5 will give you a
horizon shot (if you're lucky). The C6-7 is almost guaranteed to give
you a shot of the ground.
REVERSING THE CAMERA
Chris Tavares ([email protected]):
The original article [on reversing the Astrocam] was "Retrospective Rocketry"
in a 1980(?) issue of Model Rocketeer. It's since been reprinted by Estes in
one of their Model Rocket Newses, which you should be able to get. It may
also be available from NARTS.
[Moderator's Note: the book _Advanced Model Rocketry_ by Michael Banks shows a
couple of reverse-Astrocam hacks including a "stereo" version incorporating
two cameras hanging on either side of a large body tube. This, IMHO, would
not produce any stereo effect at altitudes above 50' due to the minuscule
baseline (the OD of the body), but would double your chances of getting
a shot. Additionally, Tom Beach ([email protected]) has a dual,
rear-facing Astrocam (tandem) which he flew at NARAM 34, a photo from
which was published in the Sept/Oct '92 AmSpam - JH]
CLEANING THE CAMERA
Jim Cook ([email protected]):
There is one hint that I don't think has been mentioned: Bring a few Q-tips
to the launch field in your range box. Use them to clean the lens before
launch.
Jack Hagerty ([email protected]):
I believe a #1 Camel's hair brush is a better cleaning tool than a Q-tip
for the mirror. Since the Q-tip doesn't bend like the brush bristles do,
the surface pressures on that front-surfaced mirror can be quite high. I'm
not sure what material is used for the "cotton" tip (rayon?) but some
synthetic fibers can be very abrasive.
To prevent dust from collecting on the mirror, I store my Astrocam/Delta
horizontally from a string with half a paper clip at each end hooked into
the launch lugs. Some people bag the camera in a plastic produce bag.
GETTING THE PHOTOS PRINTED "RIGHT"
Jack Hagerty ([email protected]):
Find a 1 hr photo place that does 110 film then have the film processed
normally. This means, of course, that the images will be reversed. If any
of the flight (or ground photos for that matter) came out well, then hand
the negatives back to the service droid and ask him/her to make some
reprints with the negative flipped. The key is that you're talking to the
person who'll be pushing the buttons so you can watch them do it.
If there's no one else ahead of you in the processing queue, they can do
this while you wait (it only takes abt 5 minutes) and if they screw it up,
you can refuse the print and they'll try again.
======================================
Other commercial camera payloads - California Consumer Aeronautics (San
Diego, CA) sells a very small Super 8 movie camera suitable for HPR
payloads, but it's not a ready-to-fly system. Cotriss Technology (San
Jose, CA) specializes in rocket photography, and sells a complete HPR
still camera system (including rocket) called the Observer.
4.1.2 Homebrew cameras and techniques:
Still Cameras
Historic - The earliest hobby type rocket with a camera was reported on
in the March 1983 issue of _The Model Rocketeer_ (the predecessor to
AmSpam) in the article "King George VI's Rocketeers." As Chris Tavares
([email protected]) reports: "A school group in Scotland formed what
is possibly the first model rocketry club [in the late '40s - JH]. Of
course, there were no commercial model rocket motors available, but they
used pennywhistle fireworks motors. The group's advisor designed and flew
a camera-bearing rocket with which he took several photos of a nearby
loch. The motors were pre-manufactured by professionals, used once, and
thrown away. The airframes were designed by the modelers, and made out
of paper and light woods. It's as valid an implementation of 'model
rocketry' as what goes on today in eastern Europe."
According to Stine (Handbook, 2nd Edition) the first true "model rocket"
(in the NAR Safety Code defined sense) camera payload was flown by Lewis
Dewart in 1961. Lewis simply strapped a tiny Japanese novelty camera to
the side of a model. The shutter was tripped by the nose cone separating.
Shortly after that, Dennis Guill upped the sophistication by taking the
shutter and lens of a similar camera and mounting it on a plastic tube
that just fit inside a rocket body tube with the lens facing forward. It
used sheet film cut into a circular negative and the cocked shutter was
released by a lanyard (a shoelace!) at ejection (sound familiar?). It was
an aerodynamic nightmare, but Estes saw enough promise to develop the
concept into the Camroc.
Current - The present wealth of lightweight, autowind cameras on the market
makes it relatively easy to design a sequence camera that shoots a whole
roll of film on a flight. A crude-but-effective setup was developed by
Peter Alway and described in Vol 3, No 2 issue of _T-5_ (the HUVARS
newsletter). Peter took a cheap autowind 110 camera and came up with a
simple arrangement of a motor, a stick and some bits of wire to repeatedly
trip the shutter. This setup was flown on an "E" motor.
A similar, but more sophisticated, system was detailed in the March/April
1992 issue of AmSpam. Steve Roberson designed his system around HPR to give
him power to boost a high quality 35mm camera to significant altitudes. He
took a relatively expensive Olympus autowind camera and triggered it with a
very solid (but simple) cam-and-lever mechanism. A nice feature of this
camera is that it automatically rewinds the film into the can at the end of
the roll which would enhance its survivability in the event of a crash. A
tribute to Steve's design and flying skills is that the camera and rocket
were retired, intact, after 22 High Power flights (H & I motors). Some more
photos of/by Steve are in the March/April 1993 HPRM. The same issue has some
killer aerial photos by Steve Lubecki as part of the "Danville 8" article.
A follow-up article in the August, 1993 AmSpam details the next generation
of this project which increased the size and sophistication significantly.
A recent variation on this theme was flown by Bob (I forget the last name)
at NARAM 34 in August, 1992. He had found a brand of compact 35mm camera
which comes equipped with "sequence" mode (i.e. it keeps shooting at ~1 fps
as long as the shutter is pressed). Additionally, the shutter is electronic
so that all it takes is a contact closure to activate (no more moving parts).
Bob had switches at several places on the rocket to trigger the camera
either as it cleared the launch rod, or at payload separation. He also used
a recovery harness to keep the lens pointed at the ground during descent.
Roger Wilfong ([email protected]) has isolated at least one make
and model of camera that fits the above criteria: "My favorite is a RICOH
Shotmaster AF Super. It has an electric switch remote shutter release and
a 'continuous' program mode. You set this mode and the camera shoots a
whole roll of film when the shutter release is held down (or the remote
contacts are shorted). The camera fits in an LOC 3" tube and even rewinds
the film at the end of the roll."
A very involved HPR camera project was covered in five parts by HPRM over
the 5 issues of 1992, but is too involved to summarize here. Parts 1 and 2
were reprinted in the March/April and May/June 1993 issues, respectively, so
that folks buying it off the rack could catch up (HPRM didn't "go public"
until halfway through the series).
Several r.m.r readers have announced projects to convert cheap film-box
cameras into payloads, but none have posted their results yet. One
ambitious soul (name please!) is even attempting to add film advance/shutter
trip mechanism to make a sequence system. We'll keep you posted.
Movie Cameras - The first model rocket movie camera was flown by Charles & Paul
Hans and Don Scott in 1962. A heavy spring-wound Bosley 8mm camera was
crammed into a payload section and lofted by an early "F" motor. The story
is still recounted by Stine in the most current edition of the Handbook.
(Note: Paul Hans currently works for ISP/Aerotech).
Due to the greater difficulty of adapting a movie camera, and relatively
easy access of Cinerocs, not too many homebrew movie cameras have been
flown, compared to still cameras. I'd be happy to include documented
examples here, if you send me the references.
4.1.3 Video
This is a new area with much work going on, and some early successes to
report. There are two ways of returning video from a rocket: record and
transmit.
Record - Following the lead of film cameras, attempts have been made to
fly stripped camcorders (using HPR, obviously!) to record the flight
while on board. Video tape recording, however, is a very delicate
technology and the accelerations encountered in rocket flight jiggle,
dislodge and otherwise move the tape all over the recording heads in
a disruptive manner. To date, I have only one report of someone making
this work. Stu Barrett ([email protected]) reports: "At a recent San
Antonio Prefecture launch, Randy Reimers (an expert video technician) had
a Sony camcorder with the camera separated from the transport via a wire
harness. He had the transport installed so that the tape was vertical to
the ground. That seemed to keep the tape on the tape heads. He did say
that under the acceleration of a K550, there was a slight herringbone
pattern on the tape during the boost that he attributes to vibrating tape
due to high G's. The J415 did not have this phenomena."
[Moderator's note: Both Stu and I agree that this sounds sideways. One
would think that the tape transport should be positioned so the tape runs
horizontal (WRT the acceleration) over the heads. The explanation seems to
be that the grooved pulleys and tape guides have no problem keeping the tape
tracking correctly, even at 10 or 20 gees (tape's pretty light!), but if
you place the cassette with its spools vertical (i.e. the tape horizontal)
the tape tends to pull freely out of the cassette under acceleration and
tension is lost. No tension, no picture - JH]
Transmit - Transmitted video has had more frequent success, but complicates the
process by adding a whole new technology. While the components that ride
in the rocket have no moving parts, you must add transmitters and antennae
to your vehicle, plus receivers and recorders to your GSE. License-less
video transmitting is allowed by the FCC, but the power limitations raise
more problems. Omni directional transmit antennae are easy to track, but
the signal strength drops off *fast* (inverse square law). Directional
antennas concentrate the signal, but require that you track the rocket, or
hope that it doesn't go too far off course!
A good, but somewhat superficial, article on transmitted video appeared
in the July '92 issue of _73 Amateur Radio Today._ Being a radio hobby
magazine, it concentrated on that aspect (and assumed you know a bit
about it) and left the rocket parts at sort of the gee-whiz level. The
system transmitted with 6 Watts (the developer was a licensed ham) and
returned a good, clear picture to an altitude of 1,200 ft. The rocket
was an HPR (no details given) but this was just the checkout vehicle for
the transmitter hardware which is slated to go into an LOX/Kerosene amateur
rocket with a design altitude of 200,000 ft.
The Jan/Feb '93 issue of HPRM had two articles on broadcast video systems;
both, coincidentally, being homebrew reworkings of the Lionel "railscope"
miniature CCD camera. While being admittedly low-res, the systems can be
made quite light. The version by Dan Green had a fight ready weight of only
3 oz which makes it capable of being flown by a "C" motor!
The May/June '93 HPRM has a fairly lightweight article on a video transmitter
project called the "ICU2" (get it?)
Commercial - If you feel like dropping a kilobuck on the hardware, Hans
Schneider (Plainsboro, NJ) runs a much improved ad (compared to his previous
one) in HPRM offering an HPR based color/sound video broadcast system
(including rocket) for a staggering $975 (but you get free shipping :-)
Jim Cook ([email protected])informs us that Supercircuits in Austin, TX
is a good contact for miniature video cameras (B&W and color), transmitters,
and receivers. Note that the operation of this transmitter requires a ham
radio license. See Part 1 of this FAQ for the address.
----------------------------
4.2 Data Gathering Payloads
The payloads covered in this section come the closest to the "real" kind in
purpose. The whole reason for launching professional rockets is to return
information from a place that is difficult, dangerous or even impossible
to visit first hand.
The earliest data gathering payloads in model rockets were pretty crude. The
only way of returning the data was to send the recording media up with it.
Thus we had peak-reading accelerometers consisting of a spring mounted weight
scratching a line on some graph paper, peak-reading dial or mercury tube
thermometers, peak-reading manometers and...well, you get the idea :-)
It wasn't long before advances in electronics, namely small and cheap
transistors, made it possible to launch radio transmitters to return data
from the whole flight (not just the peaks) to the ground for later analysis.
Now only the sensors had to fly while the recording and analysis equipment
could stay on the ground (again, much like the "real" thing).
The astounding recent advances in electronics and computer science have
brought us full circle. The absolutely unforeseeable (at the beginning of
the hobby) degree of miniaturization in electronics has once again allowed
us to launch the recording media, but now it's in the form of a full blown
computer system small enough for even modest model rockets to loft. Rather
than getting one crude data point per flight, we can get hundreds or even
thousands while doing the analysis right on board!
4.2.1 Transmitter
Historic - According to the Stine Handbook, the first purpose-designed
model rocket telemetry transmitter was designed by Bill Robson and John
Roe. The unit broadcast on the Citizen's Band and was first publicly
flown at NARAM 2 in 1960. It was a simple multivibrator that put out a
continuous tone which could be modulated by a sensor, but what to do with
the wavering tone it sent back was left as an exercise for the reader :-)
Stine still includes the schematic for this device in the current edition
of the Handbook, although he finally admits to it being "a very old design."
Foxmitter - Using the same basic encoding principle (and still broadcasting on
the Citizens' Band), Richard Fox designed the "Foxmitter" which was described
in the May thru December '69 issues of the old _Model Rocketry_ magazine. An
improved version, the "Foxmitter-2" was detailed in the June '70 thru Jan '71
issues of that same journal. The thing that made it an advance over the Roe/
Robson design (and the reason it took so many issues to describe) is that the
Foxmitter used a basic transmitter module into which multiple sensor modules
could be plugged (one at a time). The sensors covered included a basic tone
module (for tracking purposes), temperature, humidity, acceleration and even
a microphone! A smaller/lighter Foxmitter III was described in the Sept '71
issue.
In a couple of related articles in the Aug/Sept '70 MRM, Alan Stolzenberg
used the Foxmitter as the basis for his "Bio-1" design which involved a
very clever respiration sensor to monitor the flight subject from order
Rodentia (see Section 4.3 below). This was, of course, before launching
mammals and other higher orders fell into disfavor in the hobby.
Transroc - In a case of deja-vu all over again, Estes took a well developed
homebrew design, in this case the Foxmitter, and turned it into a commercial
product. This time, they also borrowed a page from the Heathkit notebook
and let the customer do the assembly (it was also available pre-assembled).
Like the Foxmitter, the Transroc used sensor modules to let you mix 'n match
the parameters you wanted to measure. Available were the basic beeping tone
module (aka "Rocketfinder" mode), a temperature module, spin rate module and
a microphone module.
The Transroc announced the beginning of the Estes "Rocketronics" line with
its introduction in 1971. It also quietly marked the end when it disappeared
with the 1977 catalog. Note: The current "Transroc II" sold by Estes is NOT
an RF transmitter! It is an audio beeper designed to help you find your model
after landing. It can be heard by the "naked ear" several hundred feet, but
that can be extended by using the ground unit which is a highly directional
microphone with a narrow pass filter on an amplifier.
Current - Adept Rocketry in Broomfield, CO sells a large range of electronic
products including both transmitters and data loggers. I've grouped them
together in the next section.
4.2.2 Data Logging
Historic - The rise of the microprocessor coincided almost perfectly with
my hiatus from the hobby. If anyone out there has documented examples
of the first micro-p to be flown in a model or HPR, send it to me and
I'll include it here.
Homebrew - The October 1990 issue of _Radio-Electronics_ magazine had a very
long and detailed article by John Fleischer on an altimeter payload based
on a solid state pressure sensor. The system consists of three parts: an
analog board with the sensor and signal conditioning, a CPU board and a
display module. The latter stays on the ground and can read out the data
in either selected peaks (shades of the beginning!) or do a 1/4 speed "slo-
mo" playback of the entire flight. The article contains schematics, parts
lists and even board masks for etching your own. For more info on this
device, see "Transolve Corp." below.
Commercial - Along with all other aspects of the computer industry, small
"garage" type companies dominate the computer rocket payload industry.
Following are a few data logging payloads that I have information on.
As usual, caveat emptor:
Flight Control Systems of Camp Hill, PA sells a very sophisticated system
called the FP1 (Flight Pack One) Data Logger. This consists of a complete
computer system on a 1.6" wide x 11" long board into which the sensor board
plugs. The system not only logs data from the sensors, but comes with a
development system so that you can write your own programs to start/stop
data logging based on time or other flight events (e.g. staging). The ground
support software (all PC based) is quite extensive consisting of archiving
software (to upload data from the FP1 to your PC) and data analysis software
to crunch numbers once it's there. The standard sensor board has altitude,
velocity and temperature sensors on it, but they also provide a prototype
board for designing your own. The sensor board can be remote mounted from
the CPU board. Price for the FP1, sensor board and software is a rather
substantial $300.
Transolve Corp, Cleveland, OH - Sells the "A2 Micro Altimeter" which sounds
suspiciously like a production version of the _Radio-Electronics_ system
described above. John Viggiano ([email protected]) clarifies: "Many of the
articles in _Radio-Electronics_ are thinly veiled advertisements. In this
case, it would appear that the author was writing on behalf of Transolve, in
order to sell the kit. Transolve is listed in the article as the source for
a pre-etched PC board, or the same board with all the necessary components.
In addition, the Transolve logo appears in the photo on the issue's cover."
Adept Rocketry, Broomfield, CO - Has quite a line of electronic products
including peak reading & continuous altimeters and on-board computers. A
few of these are reviewed by Tom Beach ([email protected]): "Entry
level is a $49 altimeter. Relatively small (BT-50?..I don't have the specs)
you launch it into the air, and when it returns it will be beeping out the
maximum altitude (beep-beep-beep...beep-beep...beep = 321 feet). A $79
version will log the altitude data into EPROM for later recovery and
downloading. [They also have] on-board computers (four models, most with
built-in altimeters). Coming in the future there are transmitters in the
$10-$20 range.
Finally, we have from the r.m.r address list the following entries on which
I have no info outside of the tag line in their list entry:
Langley Autosystems in Sunnyvale, CA is listed with "Datastick on-board
computer"
High Technology Flight in Ypsilanti, MI sells "Electronic Payloads".
[Moderator's note: There are quite a few electronic timers, beepers and even
sophisticated micro-p based flight controllers sold by several companies.
These are usually used to control staging, recovery deployment and aid in the
recovery itself. While of the same general nature as the electronic payloads
just described, they are not technically payloads, but rather part of the
carrier rocket itself. I have not included them for the same reason I haven't
included mercury switches and tempura paint, i.e., they're not payloads.]
4.2.3 Sample collection
This final type of data collection is practiced only rarely by
professionals. True, some satellites are designed to be returned for
study (the LDEF is a notable example), but outside of Earth orbit, the
only unmanned "sample return" missions have been some moon rocks brought
back by the Soviet "Luna" series.
I have only one documented example of sample collection by model rocket.
In the anthology "Advanced Model Rocketry" complied by Michael Banks,
there is an entry by Eric Nelson describing a system used to collect
atmospheric pollen and spore samples. It used an Estes Omega to loft a
sampler consisting of a hollow nose with a clever arrangement of springs
and marbles acting as check valves.
----------------------------
4.3 Bio-payloads
The official position on biological payloads can be summed up in one word:
Don't.
The perfectly reasonable rationale here is that this is an educational
hobby and you really aren't going to learn anything new by torturing your
pet gerbil or lizard to see if he'll survive (and if he doesn't, how will
you know what killed him? Launch shock? Burnout deceleration? Recovery
deployment? Impact?)
With that disclaimer out of the way, though, we must admit that there
are other reasons for launching living things, as any 10 year old can
tell you. If you have to do it, though, try to stay outside your own
Phylum :-) No one's going to get too upset if you launch a few plant
leaves (Some HPR guys even use lettuce as recovery wadding) and few
are going to risk the hypocrisy of objecting to a gastropod-naut after
killing hundreds of them with snail pellets the week before.
Be careful if you start venturing into the Chordates, though. While I'm
sure there have been more rocket riders from Class Insecta than all other
bio-payloads combined, stay out of Vertibrata. Anything with a backbone
is a definite no-no.
----------------------------
4.4 Guidance Systems
I am about to violate my own rule established in the "Data Logging" section
above which draws the line between equipment lofted as a payload and similar
equipment lofted as a part of the rocket structure (e.g. electronic timers).
The only universally accepted method of model/HPR guidance is the static
fin. While these take on an enormous variation in shape, size and location,
they all do the same thing: move the CP back so that the rocket is statically
stable. Since the beginning of the hobby, folks have been experimenting with
more sophisticated ways of guiding their rockets for lots of different
reasons. While it can be argued that these systems are part of the rocket
proper and not a payload, every one of them so far has been an experiment;
the rocket's raison d'etre. The rockets carried no other payload and would
not have existed otherwise. None of the systems have been so successful that
the technique has been incorporated into a "regular" rocket to carry some
other type of payload.
With that waffling out of the way, here is an overview of different
techniques attempted over the years. First though a little discussion on
guidance in general. [See "Pendulum" below for a reference to an excellent
article on the dynamics of active control]
4.4.1 Guidance, Active vs Passive - All hobby rockets, with the exception
of the experimental ones described later, are passively stable. They achieve
this by the simple expedient of placing the CP behind the CG, which is
almost always done with fins. Static fins are placed at the back of a rocket
because that's where they are needed to provide negative feedback. As much
as this sounds bad to the touchie-feelie crowd, negative feedback is simply
an engineering term which means that any disturbing forces are fed back into
the system in the opposite direction. Thus any force which causes, say, a
positive pitch will make the fins generate a negative pitch force to help
put it back right. Positive feedback, conversely, causes continued motion
in the *same* direction, exemplified by the tight spirals of an unstable
rocket where the fins push it further in the direction of the error.
I say that static fins 'help' put it back right because, being a passive
system, it has no way of knowing which way 'right' is. If you launch
vertically with a side wind, then static fins will steer the rocket to a
direction which is a combination of the side wind and the apparent wind
caused by the rocket's own motion (this is known as vector addition and will
come up again further down). We all know this as 'weathercocking.'
Active fins are a whole 'nother story (we'll continue using fins in this
discussion even though there are many different ways to affect a rocket's
flight path as we will see later in the 'Gyro' section; fins are just the
most common). Active fins are usually pivoted on their root edge like the
rudder on an airplane. The biggest debate on active fins is which end of
the rocket to place them. Both front and rear have their trade-offs.
Rear Mounted Fins: Rear mounted fins seem more "right" because that's where
we're expecting to see them. They also have a legitimate benefit in that
should the guidance system fail, the fins will add to the static stability,
just like always. One consequence of rear mounted fins to keep in mind is
that the control inputs must be reversed. Just as an airplane rudder must
push the tail left in order for the plane to turn right, rear mounted fins
must turn in the direction of the error to correct the rocket's path. This
leads to them being very effective since you get to add the fin's angle-of-
attack (alpha) to the rocket's.
For example: If the rocket develops a 5 degree alpha with respect to the
vertical, then the fins, since they're pivoted the same direction, will
add another 5 degrees thus doubling the amount of corrective lift generated
(assuming of course that the angles are small enough that the fin doesn't
stall). The down side of this is that the fins might prove *too* effective
and could cause the rocket to overshoot its desired path and head the other
way. This could lead to an unstable oscillation if not damped out. One
way to lessen their impact is to make the fins small, which has the usual
benefits of less weight, less drag and (if this is a scale model of a
finless missile) less visual impact.
Other problems with rear mounted fins is that the back end of a rocket is
already a pretty crowded place. There's that massive heat generator (the
motor) taking up most of the airframe, and the last thing you need is more
mass from fin actuators, bellcranks, bearings, etc. at the "wrong" end
detracting from the rocket's static stability.
Front Mounted Fins: For front mounted fins, one is tempted to say "take
everything in the previous section and reverse it" :-) It's not quite that
simple as they have their own subtleties. The visual response from seasoned
rocket designers is usually a shudder since front fins are what everyone is
always trying to avoid. Indeed, should the guidance system fail they will
pull the CP forward enough to make the rocket statically unstable. For this
reason, forward mounted fins are almost never used by themselves, but rather
in conjunction with static rear-mounted fins to provide "trim."
Front mounted fins are not very effective; the reason being that when
they're up front, the fins *subtract* their angle of attack from the
rocket's. Think of it this way: While the rocket is ascending vertically,
the fins are also vertical, of course. If a gust of wind induces, say, a
positive pitch then the control system will command the fins to a negative
pitch position. This puts the fins nearly vertical again with almost *no*
angle of attack WRT the relative wind to generate corrective lift. It's not
until the rocket starts developing some horizontal velocity (since the motor
is no longer pointing completely vertically -- vector addition again) that
the fins start generating some lift to put the rocket on course.
While this makes front mounted fins less desirable as a primary guidance
solution, it actually enhances their use as guidance trim. By adding active
forward mounted trim fins to a basically stable rocket (with static rear
fins) you can "fly it all over the sky." Since the fins are less effective,
your steering inputs don't have to be so subtle and the risk of overshoot is
greatly diminished. As speeds increase you really don't want a control system
that's too "touchy." This is, in fact, why supersonic missiles like the
Sidewinder and AMRAAM use exactly this control scheme.
Finally, front mounted fins can have all the benefits that rear mounted fins
lack: system comptactness (since the control system, fins and actuators are
all at the same end), static balance (all the system mass is at the front),
avoiding the heat and space restrictions around the motor, ability to be
recovered separately in their own payload compartment, etc.
Well, with that "ground school" out of the way, let's get on to some
specific examples:
4.4.2 Historic - Ram Air. The old _Model Rocketry Magazine_ carried a two part
article by Forrest Mims in the February and March 1970 issues on Ram Air
guidance. In this system, air entering through a hole cut through the
central axis of the nose cone was redirected out side ports by a rotating
duct. The idea was that under normal flight, the air would "puff" out the
four side ports (along the pitch and yaw axes) in rapid succession causing
no more than a wobble in the flight path. When you wanted to change course,
the duct would be quickly stopped in front of the appropriate side port to
let air effect the change then it would go back to spinning. The problem
(which should have been obvious, IMHO) is that a flying rocket is a classic
free body and that the torque necessary to start and stop the spinning duct
would cause the rocket itself to spin the opposite direction. This means
that the port you were lining the duct up with was no longer aimed in the
"right" direction. The system used a sun-seeking sensor which looked out the
central ram air inlet.
An equally creative (and unworkable) guidance method by the same author was
detailed in the Nov '70 MRM. This one started out the same with a central
ram air inlet and a side port (but only one). Inside the side port was a
pair of electrical contacts connected to an enormous capacitor. The air
entering the top spun a small propeller connected to a screw. The screw
closed the contacts discharging the capacitor and causing an acoustic wave
to exit out the side port. The idea was that this acoustic wave could be
used to influence the rocket's path. Of course, this setup was just used to
see if any course change was detectable at all (it wasn't). How to recharge
the capacitor and time/aim the discharges was left as a project for future
generations :-) Gotta give this guy an "A" for lateral thinking!
4.4.3 Sun/Horizon (target) seeking - The Ram-Air system described above was
a sun seeker, albeit a very crude one. The sun is a marvelous target for
experimental guidance systems. It's massively bright, so it's easy to
detect (in fact, it's hard to miss :-). It's always "up" in the sky [if
you're not launching too close to sunrise or sunset] so you don't have to
worry about violating the safety code WRT flight path angle. Finally, it's
out at infinity, so you don't have to worry about actually reaching it (i.e.
a constant target).
Perhaps the most in depth sun guidance system yet built was done by the
Zunofark team of George Gassaway, Matt Steele, et. al. and covered in mind
numbing detail in the May/June and July/August 1992 issues of HPRM. The
articles are a reprint of the research paper that took first place in the
Senior division at NARAM 30. It covers all phases of the project from basic
theory and construction details through experiment design and execution.
The research vehicle used the static rear fins/forward trim fins control
scheme. Control input was by a quadrature style sun sensor looking through
either a transparent or translucent nosecone. Fin actuation by RC airplane
type servos. The articles include appendicies.
4.4.4 Pendulum - An article of similar depth to the "Sun Seeker" above, but all
theory, was presented in the July/August 1993 HPRM. Author David Ketchledge
starts with the basics by revisiting the famous Barrowman Equations for
determining the CP of a rocket. He then continues on to explore the dynamics
of rocket flight. My only problem with the article is that the equations are
presented in FORTRAN or BASIC style arithmetic statements rather than using
standard mathematical notation which makes it difficult to follow. At the
end of the article, Mr. Ketchledge proposes a guidance system design based
on a free hanging pendulum to use as the vertical reference. He provides
multiple computer simulations to show the effectiveness of this sensor
compared to several others (including the Zunofark sensor described above).
While an interesting concept, I would like to see one built before buying
into the effectiveness of this sensor. Any force, such as a strong gust of
wind, that produces a linear side motion will cause the pendulum to swing,
erroneously detecting an off-vertical condition. Conversely, a translation/
rotation motion (such as the "coordinated turn" so prized by airline pilots)
might fool the sensor into not detecting an off-vertical condition or, at
least, detecting it incorrectly. The bottom line is that a pendulum doesn't
simply hang "down", but rather in the direction that is the combination of
gravity and the rocket's acceleration (vector addition yet again!).
4.4.5 Gyroscopes - This one's going to need a little more ground school.
Gyros fascinate us because they violate our common sense perceptions of
mass and force. Everyone who has played with a toy gyroscope marvels at how
it "resists" the twisting and turning of your hand. Eventually, most rocket
hobbiests come up with the idea that if you put a gyro on board a rocket
then it would "resist" all of the external disturbing forces and cause the
rocket to fly straight without any fins.
Sorry, it doesn't work that way.
Gyroscopes work on the principle of rotational inertia. Just like with linear
inertia (where a mass moving along a line will continue along that line
unless disturbed by an outside force) a mass set spinning on an axis will
continue to spin around the same axis unless forced to change. If you do
force it to change, however, the results are not what you'd expect.
The reason the passive gyro won't work is due to the physics of rotation. The
basic gyro "law" is as follows. Gyroscopes have three axes: the spin axis,
the input axis and the output axis; all at 90 deg to each other. Twisting
the gyro about the input axis will cause a torque about the output axis.
Putting this in rocketry coordinates, if the gyro rotor is spinning on the
long (roll) axis of the rocket, then anything that causes a rotation about
the yaw axis will torque the rocket in pitch and visa-versa. This means that
if you launch your finless rocket with a gyro spinning vertically, then a
gust of wind from the North will cause it to veer East or West (depending on
which way the rotor is spinning).
"Well," some folks argue, "then all I have to do is put another gyro with its
rotor spinning along the yaw axis and maybe a third spinning on the pitch
axis. That should 'resist' torque from any direction." Sorry again. Just as
weathercocking is an example of linear vector addition, the angular momentum
of spinning gyro rotors add up in the same manner. Three rotors all placed
orthogonally will cancel each other out (vectorially adding up to zero) and
act as if they weren't even there (except that you'll be lifting a *lot* of
useless mass :-).
The correct way to use gyroscopes in a guidance system is as a REFERENCE
PLATFORM. What that mean? Well, remember how a spinning rotor will continue
to spin on its initial axis unless disturbed by an outside force? Rather
than lashing the gyro to your payload section and forcing it to twist with
your rocket, it should be mounted in a gimbal (a two axis bearing originally
invented to keep ships' lanterns vertical in heavy seas). In this way, no
matter how much your rocket pitches and yaws, the rotor will continue to spin
about the same axis it started with on the pad. With this constant "up"
reference, you can build control systems to keep the rocket heading in that
direction. There are several ways to do this:
4.4.5.2 Fins, Mechanical - This is probably the closest thing to the ideal
passive gyro that everyone thinks of since it's all-mechanical. With a
fairly massive gyro rotor spinning in a gimbal, belcranks can be run from
the gimbal axes down to the fin pivots. The only tricky parts are remembering
to cross the belcrank rods to get the reversed action required (See "Rear
Mounted Fins" above). Also, some means of providing recovery that doesn't
blast the gyro and linkages with ejection gas is needed.
I've heard of such an all-mechanical design by word-of-mouth, but was unable
to find any references in either AmSpam or HPRM (but my collection only goes
back to late '91 for the former and mid '92 for the latter) so I decided to
design my own. It uses RC airplane components for all the movable pieces
(cheap and reliable) with a homebrew gyro and gimbal. It will be about the
size and shape of a LOC Onyx, since that will give me a baseline comparison.
4.4.5.3 Fins, Electronic - The more sophisticated approach to gyro control is
to use a "real" electronic control system combined with the reference
platform. While I haven't found any reference to such a system actually
being built, an excellent source to draw from would be the Zunofark design
described above. If one were to replace the 4-direction Sun sensor with
rotational position sensors on the gimbal axes (along with the appropriate
signal conditioning), you would have a very workable setup. A setup, one
might add, that could be programmed to head in any direction, not just
towards an external signal source (can you say "Inertial Guidance"? I knew
you could :-)
Historical note: This is exactly how the German V2 guidance system worked,
the only differences were in the details: It had fixed rear fins for basic
stability but rather than use forward mounted fins for trim (since it had
to travel outside the atmosphere) it used graphite vanes to vector the
exhaust slightly. Plus, of course, it didn't have modern digital electronics
but used very similar analog predecessors. Also, the gyro platform had a
three axis gimbal so that roll was controlled as well as pitch and yaw.
The gyro platform was set up to keep the rocket absolutely vertical WRT its
launch site. To hit a target, the launch pad was aligned with the rocket's
pitch axis aimed towards the target. After liftoff, an actuator pushed
on the pitch axis of the gyro forcing it off center. The guidance system
interpreted this as an error and "corrected" it by pitching the rocket the
other direction (towards the target). As the actuator continued to push,
the rocket continued to pitch over until it ran out of fuel; at witch time
it was (theoretically) directly over the target and heading straight down.
Range was controlled simply by controlling the rate of the pitch actuator
and how long into the flight the pitch program started.
4.4.5.4 Gimbaled Motor - The only example of hobby rocket guidance done the
way the "big boys" do it, was covered (somewhat sketchily) in the May/June
1993 issue of HPRM. Richard Speck designed a gimbaled motor system consisting
of a two axis gyro reference platform combined with a two axis motor gimbal.
This was an all analog system which even included phase comparitor circuitry
to prevent over correction. The first version of the test vehicle hedged its
bets and included fins, but the second one had none; a true finless missile!
The design was used as a basis for an eight foot "high fidelity" Saturn V
model with five engines in the first stage; the central one being fixed and
the outer four each being on a one axis gimbal along the pitch and yaw axes,
just like the real thing! A "progress report" photo appeared in the Sept/
Oct 1993 issue of HPRM.
4.4.5.5 2nd Gyro torquing - Finally, there is a technique for controlling
rocket attitude without fins, gimballed motors or any outher external
affectations (look it up). In fact, it's very close to the presumed ideal
of a gyro that "resists" external forces all by itself. The technique was
originally used to stabilize ocean liners along their roll axis but is now
used in some spacecraft to do attitude control without the use of gas jets.
The first thing you need is a reference platform to tell you which way is
"up". This can be a small mechanical gyro with encoders on the gimbal axes
like we've been discussing, or even a non-gyro system like horizon sensors
(this is the way satellites do it) or a "target" sensor like sun guidance.
The second part is the control gyro. It must be fairly massive and positioned
somewhere around the rocket's CG. Actuators are placed on the gimbal axes so
that when the reference platform detects an error, say on the yaw axis, the
actuator twists the gyro's pitch axis which forces it to precess in yaw. If
you've got the signs hooked up right, this will counter the disturbing yaw
and put you back on track.
While the theory is good and has been proven out on real spacecraft (such as
the "Magellan" Venus orbiter) it all seems quite involved for a hobby rocket.
I'm sure someone out there will try it for just that reason :^)
----------------------------
4.5 Novelty Payloads
This section is the catch-all for everything else your rocket might carry
outside of its own structure. If you can think of a broader category for
some of these things, let me know and I'll consider re-arranging it.
4.5.1 Contest Payloads.
NAR standard payload - It wasn't long after the founders of the hobby had
the propulsion and airframe parts of the system sorted out that they
wanted to do "something else" during contests. Thus was the idea of
lofting a "dead" weight born. The first NAR standard payload was a slug
of lead 3/4" in diameter weighing 1 oz. Later, this was changed to being
a cylinder filled with sand. The official description (from the Pink book)
reads: "The standard NAR model rocket payload is a non-metallic cylinder
filled with fine sand, with a mass of no less than 28 grams [1 oz]. This
cylinder shall be 19.1mm [3/4"] in diameter and 70mm in length."
Tripoli water payload - As with everything else in HPR, their standard contest
payload is larger than life :-) They figured that if the standard NAR
payload is one ounce, then the standard Tripoli contest payload should
be one pound. Rather than using lead or sand, though, they upped the
difficulty by using water. Also, there is no standard container for the
water, just a requirement that the airframe be at least 2.25" diameter at
some point and be able to hold 16 fl oz of water. The payload compartment
is weighed both before and after flight to make sure that you didn't leave
any "vapor trails" during flight. One added wrinkle is that everyone must
use the same 36" chute, one of which is provided to each contestant.
Eggs - According to Stine, the idea of flying raw eggs is attributed to
Captain David Barr of the USAF Academy in 1962. Originally, this was used
as a qualification test to see if you had the skills to launch a biological
payload with a good chance of getting it back alive. It quickly took on a
life of its own, so to speak, as a competition. The "official" raw egg is
described in the Pink Book as: "a raw, USDA Large hen's egg with a mass of
no less than 57 grams and no more than 63 grams, and measuring no more than
45mm in diameter." Credit for the first successful eggloft is given to the
same Hans/Scott team that flew the first movie camera (q.v.)
4.5.2 Ejecting payloads
Generally speaking, the hobby discourages ejecting things out of your
rocket (other than the recovery system, of course!) so as to not appeal too
much to the "warhead" mentality that we run into all too often. However,
there is great crowd pleasing effect to be had in dropping a bunch of
colorful "ejecta" for everyone to chase.
Versions of this type of rocket have been around for some time. Plans
for a "concept" rocket called "The Purple People Eater" by Ken Brown were
published in the December, 1980 issue of _Model Rocketry_ magazine. The
model drops various types of streamers and "flutterers" at ejection. A
larger version of this model was flown by Chris Tavares off of NARAM 34's
sport range in August, 1992.
Expanding on the concept, the "ZIA Spacemodelers Sport Design Notebook"
compiled by Tom Beach ([email protected]) contains a design by John
Pratt called "Bombardment." Capitalizing on various novelty toys available
on the market, this model carries three foam gliders (Guillow Co. "Delta
Streak") as parasites and has a modified egg capsule crammed with all sorts
of goodies. Included are three "Pooper Trooper" parachuting army figures,
six "Re-entry Vehicles" made from strips of trash bag taped to rubber washers
and a hand full of "Penetration Aids" (black confetti) thrown in for good
measure.
Once again Estes came along and formalized the idea with a production
version they call "Bailout". This is nothing more than a wide diameter
rocket with a body tube big enough to hold an action figure (e.g. GI Joe).
The kit includes an extra parachute for the figure, but you have to supply
Joe. Despite the appearance, the figure does *NOT* leave via the "hatch"
on the side. That's just a decal. He ejects out the top with the regular
recovery system. Reports on r.m.r of success with this model have been
mixed, mostly because the recommended "B" motors are awfully wimpy to loft a
100+ gram model (Joe usually prangs before his chute unfurls), and the
recommended "C" motor is the "CATO-master" C5-3.
Speaking of CATOs, Estes also has a model of the same name which sort of
fits in this category. While it technically doesn't eject anything, it
does break apart in the air and comes down in pieces. Estes is supposedly
dropping this from their lineup due to poor sales (it goes against the
grain of most rocketeers who do everything in their power to keep their
rockets *together* :-) but having witnessed one, I can say they're
great crowd pleasers!
Back on the ejection front, John Viggiano ([email protected]) reports: At
a November, 1992 Tripoli launch the announcer said, "This one's going to
eject a roll of toilet paper." Sure enough, an extremely long yellow
streamer was seen coming down. It actually turned out to be a roll of that
yellow polyethylene "CAUTION" streamer that you can get at hardware stores
for cordoning off excavation sites. He had about a ten minute winding-up job.
Finally Buzz McDermott ([email protected]) fills us in on some eccentrics
down in the southland: "A DARS member, Jimmy Cleek, has built a 3" diameter
rocket he calls 'Tomato Rain'. True to its name, he launches several small
tomatoes and ejects them as part of its regular flight plan. He has also
ejected candy at an Easter launch. Jack Sprague, also of DARS, has a model
in which he ejects up to 1/2 dozen MIRV's at apogee. The MIRV's are the
little Nerf-darts you can get at toy stores. Another favorite payload to
eject at DARS demo launches is a number of pennies, each taped to the end
of a 6" x 1 1/2" crepe paper streamer. Makes for a great demo flight. All
variations on the same theme....
|
| 33.14 | FAQ Part 5 of 5 | VERGA::KLAES | Quo vadimus? | Wed Mar 02 1994 12:38 | 1053 |
| Article: 15946
Newsgroups: rec.models.rockets
From: [email protected] (Buzz McDermott)
Subject: Frequently Asked Questions - Part 5 of 5
Organization: NETCOM On-line Communication Services (408 241-9760 guest)
Date: Wed, 2 Mar 1994 04:36:29 GMT
Rec.Models.Rockets FAQ (Frequently Asked Questions): Part 5 of 5
Last Modified: 1 March 1994
*** PART 5: SCALE MODELING AND COMPETITION
Section 5.1: Scale Modeling
NOTE: This section was originally edited for the FAQ by Bob Biedron, the
current FAI World Champion scale spacemodeler. It has since been
edited by others, including Buzz McDermott and Peter Alway.
Opinions expressed in this section should not be taken as those of
Bob, and should be considered a composite work of submitters to this
section in general, and not endorsements by any one of the editors/
submitters.
5.1.1 I would like to make a scale model of the <??> rocket. Where do I
start looking for technical data, dimensions, flight substantiation
data, etc.?
A great place to start looking would be Peter Alway's book of scale data,
"Rockets of the World: A Modeler's Guide". This book was published in
1993. See Part 1 of the FAQ for address information. Peter also has
and older book, no longer in print, "Scale Model Rocketry, A Guide for
the Historian-Craftsman". Either book is an excellent starting point.
Those wanting to construct detailed models may need additional data.
This usually presents something of a problem. Back issues of
"Sport Rocketry" and "American Spacemodeling" are a source of scale
information and detailed data. The old "Model Rocketry" and "Model
Rocketeer" also had a number of articles over the years. The last
three magazines are no longer in print. With the exception of articles
in AmSpam and SRM after 1990, all photos in the above mentioned magazines
are black and white.
If none of the above sources contain data on the prototype that you
want to build, or if you require more data than is found in these
sources, then two routes are open. First, ask around - someone may
already have data on the prototype that you seek. Many (most?) people
collect data without actually ever building a model. Others never get
around to publishing their data. NASA and the National Air and Space
Museum can be good sources of data (see addresses below). If you still
have no luck in finding the data you need, try writing the manufacturer
directly. The response you get from the manufacturer depends on a couple
of factors. First, your letter must end up on someone's desk who is
sympathetic to your cause and is willing to do some digging in the
archives. Second, the data you request must still exist! - often,
blueprints, photos etc. are thrown away after the manufacturer ceases
to produce the prototype. When writing a manufacturer, be as specific
as possible about the type of data you require, and explain why you
want the material. Peter Alway has further tips for tracking down
data in his book.
There is a surprising amount of scale data out there, from simple
overall configuration drawings to those showing screw/bolt dimensions.
The following list is derived almost entirely from the one Kevin McKiou
submitted to this newsgroup in February of 1992. It contains the
majority of the scale data that has been published in the model rocket
literature to date, as well as listings of the "private stashes" of a
few individuals.
Sources of Model Rocket Scale Data
------------------------------------------------------
Available from NARTS (price below + 10% standard postage ($1.50 min)):
NARTS
P.O. Box 1482
Saugus, MA 01906
Aerobee 350-Full substantiation data with plans, three color
slides, and one b & W slide.
SP-1 $3.50
Aerobee Photos-Four 8 x 10 color photographs of the same Aerobee
350 flight as SP-1. These photos are slightly different views
than those in the SP-1 packets
SP-1A $10.50
ISQY Tomahawk-This packet contains plans, an 8 x 10 B & W photo,
and a history of this single stage sounding rocket which was
developed for the International Year of the Quiet Sun.
SP-2 $4.00
Super Loki Dart-This packet contains complete data including two
8 1/2 x 11 drawings, a label detail sheet, background informa-
tion, color documentation, and four 8 x 10 B & W photos.
SP-3 $4.00
Sandhawk-This packet consists of a set of plans, history on the
vehicle, and an 8 x 10 color photograph of the vehicle on its
launcher.
SP-4 $5.00
Scale Data Reduction Sheets-Handy sheets for competition scale
packets. Includes spaces for scale factor, prototype dimensions,
and model dimensions. Set of 10.
SDRS $1.00
---------------------------
"Sport Rocketry Magazine" is the official publication of the National
Association of Rocketry (NAR). The address of the NAR is given else-
where in the FAQ. Prior to October 1993, the journal was titled
"American Spacemodeling".
Scale Data Published:
Vanguard (B&W photo) Semi-scale Jan/Feb 1993
D-Region Tomahawk (color photos) Scale Jan/Feb 1992
Corporal Sport Scale Sep/Oct 1991
SCUD-B Sport Scale Jul/Aug 1991
Little Joe II-Part 2 (color photos) Scale Jul/Aug 1991
Little Joe II-Part 1 (color photos) Scale May/Jun 1991
Saturn V-Part IV-Apollo Spacecraft Scale Mar/Apr 1991
The Delta Family Album-Pictorial
Guide Sep/Oct 1990
------------------------
"Rockets of the World: A Modeler's Guide"
by Peter Alway. 384 pages, hardcover or wire bound softcover.
THE DEFINITIVE SCALE MODELERS' GUIDE. Currently in print. See Part
1 of this FAQ for addess.
Included in Peter's book:
1. Dimensioned drawings, color-keyed drawings, B&W photographs, and
brief histories of selected rockets:
Germany:
- Maul Photo Rocket - Winkler's HW-2 - A-3
- V-2 (A-4) - OTRAG 1
The USSR, Russia and Ukraine:
- V-2-A - V-5-V Vertikal 1 - V-11-A
- M-100B - MR-12 - MMR-06
- MR-20 - Sputnik - Vostok/Luna
- Soyuz - Small Cosmos B-1 - Large Cosmos C-1
- V-3-A Vertikal - Proton - Tsyklon
- N-1 moon rocket - Zenit - Energiya-Buran
United States:
- Goddard's March 16, 1926 Rocket - Goddard's L-16
- American Rocket Society ARS-2 - Wac Corporal
- Bumper 90 - Aerobee - Aerobee-Hi/150
- Aerobee 300 - Aerobee 150A - Aerobee 350
- Viking - Deacon - Deacon Rockoon
- Terrapin - Asp - Loki Rockoon
- Loki HASP - Super Loki Dart - Arcas
- Sparrow-HV Arcas - IRIS - IQSY Tomahawk
- D-Region Tomahawk - Sandia Tomahawk - Sandhawk
- Terrier-Sandhawk - Nike-Deacon - Nike-Cajun
- Nike-Asp - Nike-Apache - Nike-Tomahawk
- Nike-Smoke - Argo D-4 Javelin - Trailblazer I
- Taurus-Tomahawk - Hermes RV-A-10 - X-17
- Ram B - Shotput - Little Joe I
- Trailblazer II - Astrobee 500 - Astrobee 1500
- Astrobee D - Aries - Vanguard
- Juno 1/Jupiter C - Mercury-Redstone - Sparta-Wresat
- Jupiter - Juno II - Thor-Able
- Thor-Agena A - Delta B - Delta E
- Delta M - Delta II - MX-774
- Atlas-Score - Mercury-Atlas - Atlas-Agena D
- Atlas-Centaur - Scout - Little Joe II
- Apollo Pad Abort Test - Gemini-Titan II
- Titan IIIC - Titan IIIB - Titan IIIE
- Titan IV - Saturn I - Saturn IB
- Saturn V - Space Shuttle - Pegasus
France:
- Veronique - Vesta - Dragon III
- Diamant A - Diamant B - Diamant B-P4
Japan:
- Kappa 6 - Kappa 7 - Kappa 9
- Lambda 4S - Mu 4S - Mu 3S-II
China:
- Long March 3
United Kingdom:
- Skylark - Black Knight - Black Arrow
India:
- Rohini RH-75 - SLV-3
Argentina:
- Orion II
Australia:
- HAD - Aero-High
Brazil:
- Sonda 1 - Sonda 2
Canada:
- Black Brant II - Black Brant III - Black Brant IV
- Black Brant V - Black Brant X
Poland:
- Meteor 1 - Meteor 2K - Meteor 3
- RP-3 - Rasko 2
Spain:
- INTA-255
Europe:
- Europa - Ariane 1 - Ariane 4
2. Mail order Resources: Addresses for companies and institutions
selling scale drawings or photographs.
Each drawing also provides sources for more data in case you desire
more detail.
--------------------------
"Scale Model Rocketry, A Guide for the Historian-Craftsman"
by Peter Alway. 160 pages, spiral bound.
NO LONGER IN PRINT
Included in Peter's book:
1. Construction, Finishing, and Flying scale models
2. Researching Scale Data
3. Histories, Drawings & Photographs of selected Rockets
- Wac Corporal - V-2 - Aerobee (Standard)
- Viking - Deacon Rockoon - Nike-Deacon
- Aerobee Hi & 150 - Asp
- Nike-Asp - Aerobee 300 - Aerobee 150A
- Arcas - Javelin - Iris
- Trailblazer 1 - Nike-Apache - Astrobee 1500
- RAM B - Nike-Tomahawk - D-Region Tomahawk
- Astrobee D - Vanguard - Juno 1
- Atlas B/Score - Delta - Scout
- Titan III C - Thor-Able - Juno 2
- Atlas-Agena - Atlas-Centaur - Titan III E
- Little Joe 1 - Mercury-Redstone - Mercury-Atlas
- Gemini-Titan II - Saturn 1 - Little Joe II
- Saturn 1B - Saturn 5
4. Plans for Scale Models
- D-Region Tomahawk (skill level 1)
- V-2 (skill level 2)
- Aerobee 150A (skill level 4)
There is a brief history of each rocket along with each drawing/photo.
Peter also provides sources for more data in case you desire more
detail
------------------------
"T minus 5" is the bi-monthly newsletter of the Huron Valley Rocket
Society (HUVARS) NAR Section #463. HUVARS is the NAR section with
which Peter Alway is associated. In the past it has been rich with
scale data and plans. Peter Alway has been a big contributor to
this and hopefully this tradition will continue now that Peter has
published his book.
Non-member subscriptions to "T minus 5" are $8.00 (U.S. and Canada)
and $11.00 elsewhere. Send correspondence to:
Huron Valley Rocket Society
2742 Beacon Hill
Ann Arbor, MI 48104
Scale Data Published:
Sparrow-HV Arcas Sport Scale Nov/Dec 1991
RP-3 (Polish Experimental Roc) Scale Nov/Dec 1991
M100B Soviet Meteorological Roc Scale Sep/Oct 1991
Cosmos Launch Vehicle Scale Jul/Aug 1991
Vostok Launch Vehicle Scale May/Jun 1991
Sputnik Scale Mar/Apr 1991
Vertikal Geophysical Rocket Scale Jan/Feb 1991
Hermes RV-A-10 Scale Jul/Aug 1990
A-3 Early German Research Roc Scale Mar/Apr 1990
Standard Missile 1 and 2 Scale Jan/Feb 1990
Nike-Deacon Scale Nov/Dec 1989
V-2 (White Sands) Scale Jul/Aug 1989
IRIS Scale May 1989
Block 1 Saturn Scale May/Jun 1988
Atlas (various - incl plans) Sport Scale May/Jun 1987
Block 2 Saturn Scale Nov/Dec 1986
Saturn 1 construction plans Scale Mar/Apr 1986
Argo D-4 Javelin Scale Mar/Apr 1986
Asp Scale May 1969
-------------------------------
"Model Rocketry" was published by George Flynn in the late 60's
and early 70's.
Scale Data Published:
Asp Scale May 1969
Nike-Smoke Scale Oct 1969
Nike-Apache Scale Nov 1969
HAD Scale Apr 1970
Vostok Scale Jul/Aug 1970
Falcon (AIM-4E) Scale Sept 1970
Astrobee-D Scale Nov 1970
Aero-High Scale Oct 1971
D-Region Tomahawk Scale Jun 1971
Black Brant II Scale Dec 1971
---------------------------------------------------------------------
Aerospace Industry/U.S. Government Contacts:
---------------------------------------------------------------------
A very good source of photographs of NASA launch vehicles is the NASA
Photography Index which you can get for free by sending a request to:
NASA
Audio Visual Section, LFD-10
Public Affairs Division
400 Maryland Ave, S.W.
Washington D.C. 20546
(202) 453-8375
Photos can be ordered from the Index for a very reasonable cost.
-------------------------
National Aeronautics and Space Administration
History Office
NASA HQ LH-14
Washington, DC 20546
This source was recommended by a museum technician at the Smithsonian
Institution at the National Air and Space Museum (see following).
---------------------------
National Air and Space Museum
Archives (Bldg 12)
3904 Old Silver Hill Rd
Suitland, MD 20746-3190
Received prompt service (2 weeks) from Paul Silbermann, Museum
Technician. This is a part of the Smithsonian Institution.
---------------------------
Aerojet-General Corp.
1051 La Jolla Rancho Rd.
La Jolla, CA 92037
Builders of the Aerobee and Astrobee series of sounding rockets
---------------------------------------------------------------------
Display Locations
---------------------------------------------------------------------
On display at the Goddard Space Flight Center Visitor's Center:
IRIs, Nike-Tomahawk,Javelin,Nike-Black Brant,
Delta-B (bulbous fairing)
---------------------------------------------------------------------
Individuals: Please contact individuals directly to arrange for the
transfer of data and reimbursement of expenses.
---------------------------------------------------------------------
Mark Johnson
[email protected]
Army/Brunswick Percheron A Scale data, hard-copy
------------------------
Kevin McKiou
[email protected] or att!ihlpy!kwm
6 S. 211 Cohasset Rd.
Naperville, IL 60540
(708) 717-5830
(708) 979-2577 (work)
Aerobee 170 Sport Scale data, hard-copy,
postscript, EasyCad, EXF, DXF
------------------------
Rusty Whitman
[email protected]
(this is 128.183.92.58 and another machine 128.183.92.59)
The best way for people to contact me is via e-mail over the net.
Scale Drawings -
Standard ARCAS ARCAS-Robin
ARCAS (outline) WAC Corporal
AEROBEE (RTV-N-10A) AEROBEE-HI (RV-N-13A)
Nike-Cajun (ARGO B-1) HASP (outline)
Convair HIROC RTV-A-2 H.A.P. A4 test vehicle (outline)
Engineering Drawings -
DELTA-B (DSV-3B)
DELTA-E (DSV-3E)
DELTA 2914 (DSV-3P)
The scale drawings I got from the Smithsonian and were done by
Harry Stine. They are copyrighted so I need to see if I can make
copies. The engineering drawings should not present a problem.
All of these are on oversized paper so making copies presents some
difficulties. At the moment I'm mostly interested in trading scale
data with other folks, but if someone just wants a copy of something
I have I'll be glad to provide it at whatever my cost is.
------------------------
Bob Biedron
[email protected]
9 Raintree Dr.
Hampton, VA 23666 (804) 825-1497
I have many old issues of "Model Rocketry" and "Model Rocketeer",
and I am willing to make photocopies. I am also willing to make
the data below available at cost, but bear in mind that
large blueprints/drawings can be expensive to copy. Please bear
in mind that I am notorious for taking eons to respond :).
Javelin My own drawings, based on J. Randolph's data,
certified as accurate by an engineer at
Atlantic Research Corp. (manufacturer)
2 color photos. Blueprints of fins and interstage
adapters.
Astrobee-D Some large blueprints and color photos.
Most of this data can be found in more
compact form in the Nov 1970 "Model Rocketry"
article by G.H. Stine. Note: Stine's drawing
gives an incorrect dimension for the fin tip
chord
Athena-H Copies of John Langford's drawings, certified
as accurate by an engineer at Brunswick Corp.
(manufacturer). A number of b/w photos showing
details, but no overall view.
Ariane 1,3,4 Various and sundry drawings and photos, esp. of
the Ariane 3, including my 1:50 scale drawing
for FAI competition. I also have a Polish 1:55
scale drawing of the Ariane 1 for FAI.
Soyuz, Proton Russian data, 1:50 drawings for FAI (incredibly
detailed drawings). A few Soyuz color photos.
5.1.2 I've never built any scale models. Are there any recommended kits for
first timers?
The following recommendations have been made by posters to r.m.r:
For A-D powered rockets:
Estes IRIS (A-C power, sport/semi scale)
Estes Black Brant II (D power, sport/semi scale)
Larger models:
North Coast Rocketry Patriot (E-G power, sport scale)
Aerotech ISQY Tomahawk (E-G power, scale)
Estes Terrier-Sandhawk (D-E power, scale, sport scale)
5.1.3 O.K., I've done all my research, collected all the data I can.
I've even built a couple of scale kits a a warm up. Now I'm ready
to build a model I can be proud of. How do I...?
Get rid of body tube seams:
Use silkspan, applied with clear dope, or .5oz. - .75 oz. fiberglass
cloth applied with epoxy. Silkspan will require a number of
subsequent coats of dope or primer to seal the surface and fill in
the fibers of the material, while the fiberglass should only require
a few coats of primer to fill in the weave. Really deep seams in the
tube should filled with your favorite putty beforehand. Tubes covered
with silkspan/fiberglass will be less likely to have the seams pop
later on.
Sand sharp break lines in fins with diamond cross sections, like those
used on Nike motors:
You can't...use a built-up fin instead. Use 1/64 ply or thin plastic.
Cut out mirror images of the fin pattern, then score the breakline
with the back of an Xacto knife, being careful not to cut all the way
through. Gently bend at the break line. Use a spar under the breakline
to provide support and give the proper root to tip thickness
distribution. Glue the three pieces (two fin halves and spar)
together, and fill the open ends with wood and/or putty.
Form sharp edges on nose cone, transitions, etc. (when turning your own):
The most common material to turn these items, wood (balsa, bass)
just won't take a very sharp edge. Try forming the piece slightly
undersize, then apply several coats of epoxy (try to get the coats
as even as possible). Then use a sanding block to sand the surface
smooth, but don't sand all the way down to the wood. These steps
should be done without removing the part from the lathe. The epoxy
will hold a better edge than wood, and the resulting surface will
have a plastic-like feel. Make sure the epoxy you use will cure to
a hard surface in thin films...5 minute epoxy often remains somewhat
rubbery.
Simulate weld lines:
Thread can be used, but something with a flatter cross-section
usually looks more realistic. Try cutting very narrow strips
of thin plastic using two X-acto or razor blades glued together (may
need a plastic spacer between the blades to get the desired width).
The width and thickness of the strip will of course depend on the
size of the weld to be simulated, but a 2:1 or 3:1 width:thickness
ratio is about right. Paint the model body tube with primer
let dry and apply the plastic strip with a _small_ amount of liquid
cement. Use a strip of frisk film or masking tape to provide an edge
to insure the plastic strip gets applied straight. Then apply several
coats of primer to fair in the edges, sanding between coats. If
AmSpam ever gets around to publishing it, a future "Art of Scale"
will cover this in more detail.
Simulate screws, bolts, and rivets:
For large-scale models, you may be able to find small screws in sizes
0-80 or 00-90 that will do the job that will do the job (Small Parts,
Inc, P.O. Box 4650, Miami Lakes, FL 33014-0650 is one source). On
smaller models you can simulate screws by embossing slots into Sig
"scale rivets" with an X-acto blade. Sig scale rivets are available in
both round and flat-head varieties (Sig Manufacturing Co., Inc., 401-7
South Front St., Montezuma, IA 50171). To simulate really tiny screws,
emboss the shafts of the scale rivets. Socket head screws can also be
simulated using scale rivets by drilling or punching a hole in the
center of the head. Rivets can be simulated in a variety of ways. On
large scale models, Sig scale rivets may be appropriate. For small
models, the best (and most difficult) way is to emboss thin sheet
material (aluminum or plastic) using a punch and die. This method gives
very sharp definition to the rivet heads. An easier way that produces
less definition of the rivet head is to simply punch from one side of
the sheet only - no matching die is used. This allows the use of a
small spur gear (e.g. a watch gear or pounce wheel) as the punch,
thereby allowing a whole row of rivets to be punched very easily.
A sewing machine can also be used to punch a whole row in short order -
just grind down a needle to produce the correct size rivet head. Model
airplane types often use tiny drops of glue to simulate the rivet
(RC56 glue supposedly works well).
Make multiple copies of parts:
Often, an number of identical parts appear on a prototype, and it is
usually tedious to make just one of them. RTV rubber is a two-part
rubber compound that cures at room temperature. Space does not allow
a detailed discussion of the method here, but basically a high-quality
master pattern is made, over which the RTV is poured. When cured,
the rubber mold is removed. Epoxy or urethane resin can then be
poured into the cavity to make as many copies as desired at a small
fraction of the work needed to make the master. Fiberglass parts can
also be laid up in RTV molds (another yet-to-be published AmSpam/SRM
article). Check out back issues of "Fine Scale Modeler" magazine
for a number or articles on casting parts in RTV molds. This is an
_extremely_ valuable technique for the serious modeler.
5.1.4 What tools do I need:
Well, that's kind of up to you....and your checkbook. With lots of
ingenuity and perseverance, many things can be done with simple tools.
For example, nose cones and transitions can be turned with just an
electric drill (small sized ones at any rate), but it's sure a lot
easier with a lathe (see Alway's book for details on turning with a
drill). An airbrush is almost a must to have, since even the cheapest
spray gun will (with practice) give a much better finish than a spray
can. Cans of propellant to operate an airbrush are available, but are
expensive in the long run; a portable air tank (found in many hardware
stores) could provide a refillable, cheap (free from service stations)
source of air for under $30. However, having a compressor is by far the
most convenient (if you live in a humid clime, you will also need a
moisture trap). Any precision scale work will require some measuring
tools, typically a steel ruler with 1/100 inch graduations and a
caliper are sufficient. Enco Mfg., a large machine tool supplier, offers
a line of low cost rulers and calipers. Their number is 1-800-873-3626.
Those who are really serious about scale modeling and have the $$$ to
spend may want to consider a small milling machine in addition to a
lathe (small lathes like the Sherline or Unimat offer an optional
milling column). With a lathe and mill, almost anything can be
fabricated, subject only to the skill of the operator and the size
of the machine.
5.1.5 Where can I get more information on modeling techniques:
Since scale modeling is such a small segment of model rocketry, there's
not much "how-to" info in the model rocket literature. Peter Alway gives
some basic, low-tech tips in his book. For more advanced techniques,
look in magazines for the plastic model enthusiast: "Scale Modeler" and
"Fine Scale Modeler" are two examples. Useful techniques also appear
occasionally in the model airplane model ship magazines.
----------------------------------------
Section 5.2: Competition
5.2.1 I would like to get into competition. I would prefer to start with kits
rather than designing and building my own. Are there any manufacturers
making kits specifically designed for competition?
There are several sources of kits designed primarily for competition.
Some of the manufacturers are:
Apogee Components 1/2A-F: SD, PD, superroc, eggloft;
19828 N. 43rd Drive specialized competition motors
Glendale, AZ 85308 Catalog: $2
(602) 780-2WIN
North Coast Rocketry Helicopter, B/G, R/G,
4848 South Highland Dr, Suite #424 piston launcher
Salt Lake City, Utah 84117 Catalog: $3
(800)877-6032 (voice or Fax)
Qualified Competition Rockets A number of competition designs and
c/o Kenneth Brown kits for model rocketry
7021 Forest View Drive Catalog: SASE
Springfield, VA 22150
The manufacturers list described in 'Other Sources of Information'
contains many additional addresses.
5.2.2 What are the major categories of competition model rocketry?
The NAR sanctions model rocketry contests throughout the USA, and
throughout the year. The contest year runs from July 1 - June 30.
The final contest for a given contest year is NARAM, usually held
in August, after the end of the contest year. The complete list
of event and rules for model rocketry may be found in the NAR 'Pink Book',
available free to NAR members and may be ordered from NARTS.
Some of the event types are:
- Altitude (1/4A - G)
The purpose is to get the maximum altitude from a model using a
specified class of engine.
- Streamer Duration (1/4A - G)
The purpose is to get the maximum flight duration from a model with a
specified engine type using streamer recover.
- Parachute Duration (1/4A - C)
The purpose is to get the maximum flight duration from a model using
a specified motor type.
- Eggloft Altitude/Duration (B - C, D - G)
In this event the competitor must launch either one to two large raw
hen's eggs, depending on engine type and specific event, and recover
it/them, intact, crack free. The goal is either to reach the highest
altitude or have the longest duration flight, depending on the event.
- Rocket Glider and Boost Glider Duration (1/4A - G)
In these events the competitor launches a glider using a rocket engine
and tries to achieve the longest flight duration of the glider. In
boost glider the pod containing the motor may be ejected and recovered
separately. In rocket glider all parts, including the expended engine,
must stay with the model (1/4A - G). There are categories for single
wing, flex/swing wing, and multi-wing gliders. Rocket glider is
generally considered the more difficult event because the model must be
both a rocket and a glider without loosing any parts. The CG and CP
requirements for the two phases of flight are very different. There
is also an R/C rocket glider event.
- Helicopter Duration (1/4A - G)
In these events the model ascends as a rocket. Rotor arms then extend
by some mechanism and the rocket slowly descends like a helicopter which
has lost power.
- Payload Altitude (A - G)
In these events the competitor must launch one or more standard NAR pay-
loads (1 ounce each of fine sand) and recover the model. The number
of payloads increases with larger engine sizes.
- SuperRoc Altitude/Duration (1/2A - G)
These events require VERY LONG rockets (7-8 feet and more). There are
both altitude and duration variations. The trick to these events is
that the model must be recovered and the body tubes MAY NOT BEND OR
CRIMP.
- Scale Events
These are craftsmanship events where competitors build scale models of
real military or commercial rockets.
* Scale: exact replicas of space vehicles, with measurements and scale
checked VERY carefully
* Sport Scale: craftsmanship is judged, but less strict scale measure-
ment checking
* Peanut Scale: Sport Scale for small (<30cm long, <2cm dia.)
* Giant Scale: Sport Scale for large models (>100cm long, >10cm dia.)
* Super Scale: must include a scale launcher as well as model of
rocket; judged same as scale
* Space Systems: must include launcher, model of rocket, and launch
a flight with payload, predict altitude, launch within a time window,
and land within a target zone. Judged same as Sport Scale (launcher
is optional but gets bonus points).
- Plastic Model Conversion (PMC)
This event is either loved or hated. Competitors enter plastic models
of rockets or other aero-vehicles that have been converted to fly as
model rockets. The models are judged on craftsmanship, degree of diffi-
culty, and flight characteristics.
- Precision Events
These include spot landing, random duration, predicted duration,
precision duration, and predicted altitude. The competitor is given a
flight duration or altitude to try and match as closely as possible,
or must predict the altitude or duration, depending on the event. In
spot landing the goal is for the model to land as closely as possible
to a marked spot on the ground.
- Drag Race
Multi-round, elimination tournament where contestants gets points
for:
* FIRST lift off
* LOWEST altitude
* LAST to land
- Research and Development
A non-flying event where contestants enter results of research projects.
Entries on judged on completeness, contribution to rocketry knowledge,
degree of difficulty, etc.
The Tripoli "Member's Handbook" currently lists two competitive events for
high power models:
- G Motor Waterloft Duration/Altitude
The purpose of this event is to either get the maximum altitude or max
duration from a G powered rocket lifting 16 fluid ounces of water as
a payload.
- H Motor Streamer Duration
----------------------------------------
Section 5.3: Competition Tips and Strategies
5.3.1 What are some good events to try when first getting into competition? Any
'sage' advice?
From [email protected] (Buzz McDermott):
I just started competition this year. I must have asked 30 experienced
competitors where to start. I got 30 COMPLETELY DIFFERENT ANSWERS!!
They ranged from 'keep it REAL simple' to 'try everything'. Here is
a summary of the most prevalent advice. It seems to have worked for me.
- Competition requires a large stable of rockets, given all the
possible events and engine categories; start with some of the
simpler ones where a single model might be competitive in more
than one event (for example, the same model might be used for 1/2A-A
streamer or parachute duration, another model might be competitive in
any of A - C streamer or chute duration)
- Try single eggloft (B-C, duration or altitude) before trying the
multi-egg categories (such as D or E dual egg).
- Go for a good, qualified flight first; then decide if 'going for
broke' is appropriate on your second flight (this is for multi-
flight events).
- Get a teammate and enter as a team. There are too many models you
need to compete to be able to build all of them your first year.
Entering as a team let's you pool time, talent, experience, and
models.
- Don't get discouraged if you aren't immediately competitive.
Remember, the main goal is to enjoy yourself and HAVE SOME FUN.
- KEEP A LOG OF ALL FLIGHTS. RECORD WHAT WORKS AND WHAT DOESN'T.
NOTE YOUR FLIGHT TIMES, ALTITUDES, ETC. Your biggest weapon
in many events is in being able to predict how your models
will perform.
- Make a model preparation checklist for each event (i.e., a detailed,
step-by-step list of everything necessary to prep the model). Use this
list for your first few competitions. Comp models are often prepared
a little differently from sport models. The difference between winning
and losing is often just attention to detail, or lack of it, in the
heat of competition.
From [email protected] (Mark Bundick)
Note: This is a condensed version of some competition strategies for
individual and team competitors, written by Mark 'Bunny' Bundick and
posted to r.m.r. Check the r.m.r archive server for the complete posting.
The full posting points out that there are many ways to win, and the
following is just what has worked for some individuals.
Some Individual Competition Strategies:
(a) Read the Pink Book. If you don't know the rules for the event,
you can't know how to win and how to improve. Figure out the
scoring for each event, how many flights are allowed, required
number of returned flights, the reasons for disqualifications, etc.
Reading the rules will also give you some insights into how the
contest will be run. Start with the general rules then review the
event specific rules.
(b) Practice for all events where your experience is low. If you
already know how to fly parachute duration (PD), don't waste time
practicing that at your club's sport launch.. Instead, suppose you
don't do well in streamer duration (SD). Build a couple different SD
models with different streamers, and fly each of them at least a
couple of times BEFORE the contest. Take a notebook to the field
and write down what happened, or at least write it down after you
get back home. Such notebooks can be the lifeblood of your
competition model and strategy development.
(c) Improve one event a year. At the start of the season, it helps if
you pick one of your weak events for special attention during the
year. Review the existing models and strategies for the event, look
over the competition carefully during the contest year, and practice
this key event each and every sport launch or test flying session
you attend.
(d) Strive for consistent flights. Rob Justis, my old teammate from
the 70's, always reviewed our DQ's after the meet and separated
them into "DQ's for the right reason" i.e no return, and "DQ's for the
wrong reason", i.e. separation. We strove to avoid the latter
obviously. This made us terribly consistent, and with today's "two
flights count" rule, this is even more important.
(e) Fly all the events. Sounds simple, but many people don't do
this. You don't have to win the event, but if you don't fly it, you're
sure to get behind because you're conceding flight points right off
the bat to your competition. Over the course of a contest year,
you can concede 10% of your yearly total this way.
(f) Concentrate on events with high individual event weighing
factors (WF). If you have to choose events to fly, or are short of
preparation time for some of the scheduled events, prepare for and
fly the highest WF events first. Simple again right? But how many
people go to a contest and fly PD first thing in the AM cause the
wind is calm, and ignore BG which has a WF two to three times that
of PD?
(g) Refine, don't abandon, your models and strategies. Rarely do
you get super performance improvements from forgetting all you
know to adopt a totally different strategy. I've seen so many people
hop onto a design when it didn't fit their flying style and then get
burned. They switch because some guy had a super performance
at a contest, so he must have the "Holy Grail" of models. Right
after Tom Beach placed highly at a NARAM with a flexie RG, I saw
lots of folks try them, and crash. Tom had lots of flexie experience
that helped, and when regular BG flyers tried to adopt his style
without the background, BOOM! If you're serious about switching
to a completely different model, say from swing wings to slide wing
rocket gliders, then take the time to practice, practice, practice and
build up the background in the new method. There are no quick
fixes to the winner's circle.
(h) Pick your contests carefully. If you can't fly helicopter duration
(HD) all that well, and the next regional you plan to attend has two
HD events, find another contest! Sometimes, this isn't possible. But
if two contests compete for your participation at the same time,
take the one that has more of your "strong" events.
(i) Casting Your Bread: Share what you've learned with others. A
three time national champion who shall remain nameless positively
stomped every challenger in his sight. But his desire for keeping
secrets and his unwillingness to share left him with few friends, and
after a brief time, he left our hobby, poorer himself and leaving our
hobby poorer for failing to let us learn from him. The benefits of
making new friends and sharing far outweigh any short term
competitive advantage you might think you have from being
secretive. As a quotation I once read went "We have all drunk
from wells we did not dig and been warmed by fires we did not
build." So go ahead. Cast your bread on the waters. You won't be
sorry.
Hope this provides you competition types some food for thought.
I'd love to hear from anyone with comments, questions, brickbats,
etc. at [email protected].
----------------------------------------
Section 5.4: Some Model and High Power Rocketry Records
[Note: This section will contain summaries of current national and
international records for model and high power rocketry. I will
add to it as I can determine what the records are...Buzz]
5.4.1 High Power Altitude Attempts
Some of the high power records come by way of a posting from Chip Wuerz
([email protected]). Chip is part of the University of Central Florida's high
altitude rocketry project. Additional information has been taken from
several issues of _Tripolitan_/_High Power Rocketry_ magazine.
* * Some current records for NON-METALLIC NON-PROFESSIONAL Rockets: * *
---Top altitude holders:
Note: It has been reported that a 2 stage rocket at BALLS 2, August
1992, set a new altitude record by achieving over 53,000 feet
AGL. I have not been able to get details or confirmation...
[Buzz McDermott]
Altitude: 27,576 (altitude by Adept altimeter)
Set by: Pius Morozumi
Event: Black Rock V, Black Rock Dry Lakebed
Date: July 16-18, 1993
Altitude: 24,771 feet (11.7% tracking error)
Set by: Chuck Rogers and Corey Kline
Event: Lucerne Dry Lake Bed, Lucerne, Ca.
Date: June 1989, USXRL-89
Altitude: 24,662 (tracking error unknown)
Set by: Tom Binford
Event: LDRS XI, Black Rock Dry Lake Bed, Nevada
Date: August 16, 1992
Altitude: 22,211 feet (5.3% tracking error)
Set by: University of Central Florida
Event: LDRS X, Black Rock Dry Lake Bed, Gerlach, Nv.
Date: August 1991
* Notes on Pius Morozumi flight (copied from November, 1993, issue of
_High Power Rocketry_ magazine (Black Rock V, July 1993) -
Pius Morozumi flew a two-stage, K550 to K250 flight with the upper
stage configured as a boosted dart. After a five second delay, the
second stage was ignited. Redundant Adept timers were used to ignite
the second stage after the delay following first stage burn-out. The
first stage was recovered at Black Rock Five. However, the upper
stage was not recovered. Approximately seven weeks after the flight
the upper stage was found and the recording altimeter was still
readable. It registered an altitude of 27, 576. The prior record of
24,771 had stood for over three years.
* Published notes on Chuck Rogers / Corey Kline Flight:
(Lucerne Test Range Tracking Results, November 1988 - May 1989) -
New unofficial altitude record for nonmetal, amateur high power/experimental
type rockets. Possibly highest tracked flight of an amateur rocket
(metal or fiberglass construction) yet in the United States. Korey
Kline and Charles Rogers became the first recipients of the Rocket
Newsletter perpetual altitude trophy for the first flight to exceed
the previous record of 22,080 feet set with a metal rocket by the Fort
Team in May 1984. The trophy will be awarded to the next team to
exceed the current record. Record is unofficial because of some
uncertainty on the exact track. The cloud of red carpenters chalk
ejected by the rocket was barely visible (because of a background of
white clouds at higher altitudes) and high wind speeds at 25,000 feet
dispersed the tracking cloud in only 3 - 4 seconds. Trackers only
got a track on the general vicinity of the red carpenters chalk
in front of a cloud. Before they could zero in the track, the red
cloud had disappeared. The angles from the last position of the tracker
heads was used for the track, the error was only 11.7%. The tracked
altitude was within 3.2% of the postflight prediction (25,567 feet)
using the Rogers Alt4 altitude prediction program with the actual
liftoff weight of the rocket, and a preflight CD estimation from
program CD2. Undoubtedly a valid track, but because of circumstances
considered an unofficial record only. The Rocket Newsletter considers
this track an official record. This rocket used a single, custom-manufac-
tured L500-25, made by the Rogers/Kline team.
*** Note: unofficial means Tripoli unofficial. Tripoli only recognizes
tracks with less than 10% error. (Chip Wuerz) ***
* Published notes on Tom Binford's 'Cloudbuster' flight at LDRS XI
(derived from text in Nov/Dec/, 1992 issue of _High Power
Rocketry_ magazine.
This rocket was launched on Sunday, 16 August 1992, at LDRS XI in the
Black Rock Desert. The 'Cloudbuster' was a single stage rocket built
by Tom Binford. It was powered by a single Vulcan O-3000 motor with
30,000 newton seconds of total impulse. The flight was tracked to 24,662
feet AGL, but suffered an ejection failure and was destroyed on impact.
* Published notes on University of Central Florida's Flight:
(_Tripolitan...America's High Power Rocketry Magazine_, Oct/Nov 1991)
Highest tracked flight at LDRS-X / BALLS 1.
Second all-time highest track of a non-metallic high power rocket.
University of Central Florida's research project and altitude attempt
to break the current high-power rocketry altitude record of 24,771 feet
set by the KLINE/ROGERS team in 1989. Altitude attempt had been based on
3850 NS L-engine, new Vulcan L-750 engines deliver 3,000 (now known to be
less from motor testing results) newton seconds. In an attempt to make
up power loss and to provide margin on the goal altitude of 25,000 feet,
the upper stage was delay-staged by several seconds. Altitude predictions
computer simulation program predicted 28,500 feet. Upper stage flew
substantial trajectory, reaching apogee nearly 2 miles downrange.
Rocket used microprocessors / timer-controlled staging and ejection,
on-board flight data measurement package, and a radio beacon system to
locate upper stage. Track was accomplished using red carpenters chalk.
Both stages were recovered.
5.4.2 Biggest Non-metallic Rockets
1) Rocket: Down Right Ignorant
Weight: 800 pounds +
Set by: Dennis Lamonthe, Chuck Sackett, and Mike Ward
BlackRock Dry Lake Bed, Gerlach, Nv.
August 17, 1992, FireBALLS experimental launch
Description: Super scale based on Esoteric rocket designed by Ron Schultz
Height: 34' 7"
Diameter: 24"
Power: 1 O-class custom motor
5 Energon L1100 motors
8 ISP K1100 motors
(around 76,000 NS total impulse)
Materials: 24" fiberglass tubes for main body tube
1/8" aluminum plates for coupler bases and fin
mounting boxes
1/2" aluminum plate for motor thrust plate
2x5" oak boards for tube coupler assemblies
2x5" pine boards for body tube strengthening
plywood centering rings
3/4" birch fins
14" paper tubing for upper body tube hard resin/fiberglass
nose cone (originally a sounding rocket nose cone shroud)
Note: The definition of 'non-metallic' traditionally has meant
'no substantial metal components' as well as no structural
components being metal. DRI appears to push that definition
to its absolute limit, or a little beyond.
5.4.3 Other Non-professional Flights of Note
1) Rocket: Frank Kosdon metal rocket
Date: LDRS XII
Argonia, Kansas
15 August 1993
Power: Kosdon non-certified O10000 (that's O-10,000)
Materials: All metal rocket with custom manufactured motor
Altitude: 35,407 feet AGL; closed optical track
Notes: This is a special-case flight. The rocket does not
follow the rules for high power because metallic rockets
are expressly prohibitted by both the NAR and Tripoli.
It also uses a custom made motor. The motor was made
by a manufacturer with other high power motors certified
by Tripoli. It was pre-manufactured and solid propellant,
within the total NS limits of high power consumer rockets.
Tripoli does not recognize this flight, or any other flight,
for altitude record purposes unless a successful deployment
of the recovery system is observed or the rocket can be
recovered to show successful recovery system deployment.
5.4.4 Some Model Rocketry Records
The following has been extracted from the list of NAR model rocketry
records which may be found on the r.m.r archive, sunsite.unc.edu. These
are U.S. records for *model rockets*.
Category Record Date Holder Division
1/4A Altitude (unclaimed)
1/2A Altitude 219m 9/88 Neutrom Tm Sr.
A Altitude 414m 5/86 Odd Couple Tm Sr.
B Altitude 535m 8/81 A. Rose Sr.
C Altitude 756m 8/90 J. Sexton Sr.
D Altitude 860m 8/81 Lou Dick Tm Sr.
E Altitude 1387m 5/85 Lou Dick Tm Sr.
F Altitude 1820m 9/81 F. Craven Jr.
G Altitude (unclaimed)
A Payload Alt. 130m 8/91 Imploding White Sr.
Mice Tm
B Payload Alt. 199m 5/81 R. Kaplow Sr.
C Payload Alt. 553m 8/89 Spaceman Spiff Sr.
Tm
D Payload Alt. 983m 11/89 D. Lucas Sr.
E Payload Alt. (unclaimed)
F Payload Alt. (unclaimed)
G Payload Alt. (unclaimed)
B Eggloft Alt. 133m 6/86 J. Warnock Sr.
C Eggloft Alt. 363m 8/92 A. Miller Jr.
D Eggloft Alt. 526m 5/86 Alpha Omega Tm Sr.
E Eggloft Alt. 932m 8/83 J. Zingler Sr.
F Eggloft Alt. (unclaimed)
G Eggloft Alt. (unclaimed)
As with the High Power altitude attempts, the problem is as often getting
a closed track rather than getting a model higher. A higher flight does
not count unless the trackers can spot it! Sometimes the model must be
retrieved, as well. For example, the 'Ace Disaster Recovery' team got a
closed track of 603m for D Eggloft altitude at the TEX REGIONAL 93 meet
(Dallas, Texas) in June, 1993. They were unable to find the rocket after
it landed so the flight was disqualified and the current record of 526m
stands. Likewise, many high flights have been disqualified because the
trackers were unable to follow the rocket or the trackers spotted on
the ejection charge, which may have occurred prior to or after apogee.
*===========================================================================*
* END OF REC.MODELS.ROCKETS FAQ *
*===========================================================================*
|
| 33.15 | Glossary A-L | VERGA::KLAES | Quo vadimus? | Wed Mar 02 1994 12:39 | 652 |
| Article: 15835
From: [email protected] (jack hagerty)
Newsgroups: rec.models.rockets
Subject: Glossary, A thru L
Date: 26 Feb 94 09:10:26 GMT
Organization: Robotic Midwives, Ltd., Livermore, CA
Here is the monthly Glossary posting. You'll notice that it now
comes in two parts since it's grown enough that it's crossed
one of the magic size limits, and is starting to be truncated
by some systems.
Part of this is due to the help I've been getting. Larry Curico, in
particular is to be [thankedblamed] for a great deal of this month's
increase. He provided both suggestions and raw material for about 80%
of the new and updated entries this month. The recently returned Bob
Kaplow helped with another 10%, including the provocative "Davis Douche."
- Jack
================================
Following is a fairly complete overview of hobby rocketry terms, both technical
and slang. After it outgrew its slot in the FAQ, Buzz and I decided that it
should be posted as a stand-alone document while he keeps a skeleton version
in the FAQ itself.
Please note that this is a copyrighted document. Anyone is free to distribute
it in rocket club newsletters or other educational materials provided that
you 1) Ask me first, and 2) Indicate on the material where you got it (i.e. a
credit notice).
- Jack
===================================================
Changes February 1994:
Updated entries: Apogee, Kitbash, Krushnic Effect, Optimum Mass, Phenolic
New entries: Composite Material, Composite Motor, Composite Propellant,
Davis Douche, Double Base Propellant, Drop Staging, Hyperterminal
Velocity, Landis Loop, Single Base Propellant, Terminal Velocity,
Triple Base Propellant
Deleted entries: Composite
---------------------------------------------
Glossary of Hobby Rocketry Terms compiled by Jack Hagerty and Buzz McDermott
Thanks to all of the r.m.r readers who have contributed.
Any corrections, improvements, updates, or suggestions should be sent to
Jack Hagerty at [email protected].
Copyright (C) 1994, ARA Reprint Services
All rights reserved
---------------------------------------------
January, 1994
Advanced see 'High Power Rocket'
Rocket
AERO-PAC The Association of Experimental ROcketry of the PACific, a
prefecture of Tripoli in Northern California which hosts NXRL
(q.v.) each year in the Nevada Desert. Despite the name, this
is an HPR club and does not fly liquid fueled or other amateur
rocketry vehicles. It's main purpose is education through
experimentation with rocketry while following the NAR and
Tripoli safety codes.
Air Start Any motor that is started after first motion of the vehicle.
Upper stage ignition of a multi stage rocket is a special case
of air starting. Usually it is outboard boosters started after
a central motor has lifted the vehicle, or visa versa. This can
be done by a flashbulb/motion switch, timer, or simply a piece
of fuse started by the exhaust of the pad start motor.
AmSpac Deprecating but affectionate abbreviations for *American
AmSpam Spacemodeling* (q.v.)
American The journal of the National Association of Rocketry. Previously
Spacemodeling known as *The Model Rocketeer* (q.v.), it underwent yet another
name change and became *Sport Rocketry* (q.v.) starting with
the Sept/Oct 1993 issue.
Amateur Rocket The class of non-professional rocket beyond HPR. Amateur
or rockets use structural metal parts and very often the motor
Experimental casing doubles as the airframe (as with professional rockets).
Rocket These rockets can be very large and powerful, capable of placing
payloads many miles up. Activities in this field (one can
scarcely call it a hobby) include formulation and manufacture
of propellants and thus can be EXTREMELY hazardous. This is
the main reason that amateur rocketry is not to be attempted
alone. Another is expense as these vehicles can run many hundreds
or thousands of dollars and take months to build. The equipment
necessary to safely pursue amateur rocketry (sandbagged bunkers,
loading pits, standby fire truck, etc.) are quite beyond the
resources of most individuals.
Not all amateur rockets are so large. Many of the "beginner"
vehicles would qualify as HPR or even model rockets in terms
of liftoff weight and total impulse, but fail the NAR/Tripoli
codes due to their metal airframes and user-compounded propel-
lants. Note: There is a fine, but significant, difference
between using a metal cased reloadable motor with pre-manufact-
ured fuel slugs and packing a pipe with zinc/sulfur (a common
amateur beginner fuel).
Liquid fueled vehicles are becoming more popular among amateur
groups. These can produce up to 1,000 lbs of thrust for up to
a minute from a LOX/Kerosene engine which can propel the vehicle
to altitudes of over 40 miles. Some hobby!
Neither Tripoli nor the NAR sanction amateur rocket activities.
See also the "Black Rock Society", the "Pacific Rocket Society"
and the "Reaction Research Society"
AP Ammonium Perchlorate, the oxidizer used in composite rocket
motors. Other components are Aluminum powder (fuel) and
polybutediene rubber (the binder holding it all together).
This is the propellant mixture that the Shuttle SRB's use.
Apogee The highest point of a rocket's flight path. (More literally,
the point farthest on the flight path from Earth.)
AR American Rocketeer - Centuri's attempt to produce an MRN
(q.v.) clone in the late '60s. While the contents were
fairly typical (product announcements, club news, rocket
plans, reports on "real" aerospace events, etc.) it had
a curiously over-produced look to it and ran very heavy
on the advertising. Someone looking beneath the surface
would notice that there was no reader input (e.g. rocket
designs or "Idea Box" style tips); that all the rocket
plans came from the Centuri design department and the "tips"
were for problems that could be solved by items straight
from the catalog! While each issue carried a Volume/Number
identification, there was only one "Number" for each "Volume."
V1, N1 was in 1966 and continued for at least four years.
B/G Boost Glider. A glider which is boosted to altitude by a rocket
motor. The pod containing the expended motor may separate
from the glider at ejection to be returned by streamer or
parachute (this is typical but is not required). The more
aerodynamically clean glider section is then free to glide
more slowly.
Baffle See 'Ejection Baffle'
BAR Born Again Rocketeer. An individual who has re-discovered the
hobby/sport after an absence of several years.
Base Drag A component of aerodynamic drag caused by a partial vacuum in
the rocket's tail area. The vacuum is the hole created by your
rocket's passage through the air. Base drag changes during
flight. While the motor is firing, the drag is minimal since
the tremendous volume of gas generated by the motor fills this
void. The drag takes a sharp jump at burnout when this gas
disappears (note: tracking smoke has very little effect on base
drag due to its low density). Base drag can be reduced by the
use of a boattail to transition the main body diameter down to
the motor diameter which helps direct air into the evacuated
area. When properly designed, a boattail can reduce base drag
below zero (i.e. actually generate a small amount of forward
thrust) by making use of the "pumpkin seed" effect.
Bernoulli A phenomenon first described by the 18th century Swiss scientist
Effect Daniel Bernoulli who studied the pressures in moving fluid
streams. The effect states that moving air will have a lower
pressure than the still air around it. This is the principle
behind how airplane wings generate lift and why beach balls stay
"balanced" on top of fans in those hardware store displays :-)
The effect is significant in rocketry when using altimeters
or any other kind of payload that senses the ambient pressure
around the rocket. The air moving by the payload section could
cause the payload to indicate a lower pressure than the ambient
still air, thus giving a false altitude reading. The effect
drops to zero at apogee when your rocket stops moving, but the
altitude vs. time curve will be wrong.
Bernoulli A phenomenon similar to the "Krushnic Effect" (q.v.) where the
Lock rocket seems to be "glued" to the pad at liftoff. This afflicts
larger, flat-bottomed rockets launched too close to pads with
flat blast deflectors. The exhaust gasses escape at great speed
through the small annular space between the rocket and the pad
creating a venturi which generates a low pressure region at
the base. This pressure deficit can be significant, and if it
is greater than the thrust being generated by the motor, the
rocket won't go anywhere! This is quite possible as a 2" dia.
rocket has, potentially, over 45 lbs (200 N) of "suction"
available to hold it back, while a 3" rocket has over 100 lbs
(460 N)! The old Centuri "Point" was an infamous Bernoulli
locker when launched from an Estes Porta-Pad with its perfectly
matching round blast deflector.
Black Powder Basically, gunpowder. The 'traditional' model rocket motor fuel.
Used by Estes and most other model rocket companies through E
range. FSI and Rocketflight have black powder motors through
the F range. See also "AP" and "Composite Motor"
Black Rock An amateur rocketry organization founded by Tom Blazanin to cater
Society to those who find HPR confining :-) It is a serious organization
for those dedicated individuals who wish to explore rocketry in
a semiprofessional vein. It is open to all forms of reactive
propulsion: solid, liquid and hybrid.
Boattail A transition section at the tail of the rocket which gradually
narrows the body down to the motor diameter. Used to reduce
base drag (q.v.).
Boosted Dart A method of maximizing altitude for any given impulse motor. A
sub-minimum diameter, unpowered "dart" section weighted for
Optimum Mass (q.v.) is placed on top of the powered section.
At burnout (maximum velocity) the dart is released and coasts
higher than even a minimum diameter rocket could due to its small
cross sectional area. This technique is used in professional
sounding rockets (e.g. Super Loki) as well as hobby rocketry.
Booster On a multi stage rocket this refers to the sections (stages)
which drop off in mid-flight. On single stage payload rockets,
the term is used for the lower powered portion to distinguish
it from the payload section. See also "Air Start"
Burn Out The velocity the rocket is traveling when the motor runs out of
Velocity fuel. Usually the highest speed achieved by the rocket. See also
"Hyperterminal Velocity"
CA Cyanoacrylate ('super glue'). A very strong adhesive popular
for use in competition and high power rockets, as well as
'on the field' repairs. The three most common forms of CA are
often referred to as 'hot', 'gap filling' and 'slow'. Hot CA
is very thin and has strong wicking properties. It dries in
only a few seconds. Gap filling CA is a little thicker and
generally comes in 15 - 30 second bond times. Slow CA forms
the strongest bond but its bond times are also much longer.
Hot or gap filling CA is often used to tack parts into place
prior to applying a stronger adhesive with a much longer
bonding time (such as an epoxy).
Capacitive A type of launch controller which uses a large capacitor to
Discharge store electrical energy from a battery. When commanded by the
launch controller, the capacitor discharges a large current
into the igniter. These controllers are often used with large
cluster rockets to ensure all motors ignite simultaneously.
CATO A motor failure, generally explosive, where all the propellant
is burned in a much shorter time than planned. This can be
a nozzle blow-out (loud, but basically harmless), an end-cap
blow-out (where all of the pyrotechnic force blows FORWARD
which usually does a pretty good job of removing any internal
structure including the recovery system) or a casing rupture
which has unpredictable, but usually devastating, effects.
Another form of CATO is an ejection failure caused by either
the delay train failing to burn or the ejection charge not
firing, but the result is the same: the model prangs.
A CATO does not necessarily burn all of the fuel in a rocket
motor (especially true for composite fuels, which do not burn
well when not under pressure). For this reason you should be
especially careful when approaching a CATO.
Origin:
Opinions on the meaning of the acronym range widely. Some
say it's not an acronym at all, but simply a contraction of
'catastrophic' and should be pronounced 'Cat-o' (which sounds
better than 'cata' over PA systems :-). Others maintain that
it is an acronym but disagree on the meaning, offering a
broad spectrum of 'CAtastrophic Take Off,' 'Catastrophically
Aborted Take Off,' 'Catastrophe At Take Off' and the self
referential 'CATO At Take Off.' All of these are pronounced
'Kay-Tow', like the Green Hornet's side kick. It has been
pointed out, though, that all of the above are 'post-hoc'
definitions since LCO's were using the term over range PA
systems long before any formal acronym was established.
Opinions on the origins say that it is either from the military
rocket programs of WW II, the post war development era, or even
a modroc-only term which originated with the MESS (Malfunctioning
Engine Statistical Survey) performed by NAR's Standards and
Testing committee. There is also a claim that it started with the
Boston Rocket Club and that the spelling has evolved over the
years. It supposedly started out as 'KATO' which, of course,
stood for KABOOM At Take Off!
CHAD Acronym for CHeap And Dirty. Used to refer to a quick and
inexpensive (but usually inelegant) way to solve a particular
problem or produce some end result.
CHAD Staging A simple technique used to make a multi-stage rocket out of a
single stage vehicle. A booster motor is taped to the end of
the standard, single stage motor in the rocket. The booster is
totally external to the rocket. The booster is then ignited in
the usual manner. This technique only works with black powder
motors. It will only work with models that are VERY over-stable
to begin with. When CHAD staging does work, however, it is the
most efficient staging method because it minimizes increased
drag and mass associated with an added stage. (See Optimum
Mass)
Chuff A form of unstable combustion marked by brief bursts of thrust
separated by periods of no thrust. Typically, the bursts come
faster and become longer as burning proceeds, until stable
burning results. The sound of chuffing is similar to that of a
steam locomotive starting up. It generally occurs in a composite
motor that is ignited too low in the grain.
Chuffing can be dangerous, since a short burst of thrust can
launch the rocket off the launch rod, and a lull immediately
following the burst can put the rocket on the ground. When
stable burning ensues, such a rocket will be flying
horizontally. See "Land Shark"
CG Center of Gravity. The point about which a free body will
rotate when disturbed by an outside force. For a model rocket,
this is the point where the effects the masses of the individual
components cancel out and the model will balance on a knife
edge. As with a see-saw, a mass further from the CG will have a
greater effect than the same mass closer in.
Cluster A rocket that fires more than one motor simultaneously. See
also "Davis Douche"
Composite Hi-Tech materials, other than paper, wood or metal, used in
Material the construction of rockets (see also "Phenolic").
Composite The term used broadly to cover solid fuel rocket motors using
Motor propellants other than black powder. Composite motors require
different igniters and igniter systems from black powder motors.
Composite In Hobby Rocketry, any propellant other than black powder. In
Propellant military parlance (where the term originated) the term is used
to denote propellants that are mixtures of oxidizers and fuels
and to distinguish them from Single, Double, and Triple base
propellants (which are either monopropellants or mixtures of
monopropellants). Note that by the military definition, black
powder is itself a composite propellant because it consists
of separate oxidizers (KNO3 and sulfur) and fuel (charcoal).
Further note that by the hobby definition, single/double/triple
base propellants are composites because they are not black
powder. No ambiguity arises, however, since the military
doesn't use black powder (in rockets, anyway), and no hobby
rocket motors use single, double or triple base propellants.
See also "Single Base Propellants", "Double Base Propellants" and
"Triple Base Propellants"
Confirmation The process whereby a member of Tripoli or the NAR becomes
Certification certified as eligible to purchase high power (H and up) motors.
Continuity A group of electrical techniques for checking the firing
Check circuit through the igniter to ensure that the circuit is
functional. This usually involves some type of light or audio
tone activated by a push-button. The techniques range from a
simple current limiting light bulb or buzzer placed in series
with nichrome igniters, to sophisticated bridge circuits for
sensitive, low current flashbulbs and electric matches.
Copperhead(tm) The trademark name for an igniter produced by AeroTech, Inc.
It is a laminated assembly consisting of a two copper foil
strips separated by an insulator, with a quantity of pyrogenic
compound on one end. It normally requires a special clip for
electrical connections, but some rocketeers have mastered
the "Z-Fold" which allows use of normal alligator clips.
Core Sample Synonyms describing a failure mode where the model comes down
Tent Peg fast and hard (nose first) and ends up tail-high in the ground
Lawn Dart (this is where large, colorful fins come in handy :-). Often
Yard Dart the nose cone has separated (taking the recovery device with
Ballistic it) and the body tube ends up containing a nice 'core sample'
Auger In of mud/dirt when pulled out of the ground.
CP Center of (Aerodynamic) Pressure. The point on a rocket
where stability-restoring forces due to airflow against the
back part of the rocket (fins, etc.) exactly equal the disturbing
forces against the part of the rocket ahead of that point.
The location of this point depends on the rocket's orientation
at the time of measurement. If it is at a very small angle to
the "local wind" (line of flight), the fins' restoring contri-
bution will be large, while the nose's disturbing contribution
will be small, resulting in a CP that is way back. The CP in
this case can be located using the Barrowman Equations. If the
rocket is nearly sideways, the CP will be much more forward.
The CP in this case can be located by balancing a cardboard
silhouette of the rocket.
Since all free bodies can rotate only on their center of mass,
stability is usually a simple matter of placing your CG ahead
of your CP, which ensures that the restoring forces of airflow
on the rear of the model will always overcome the disturbing
forces on the front.
A good rule of thumb for sport models (both high and low power)
is to design the rocket with the CP one or two body diameters
behind the CG.
CPSC Consumer Product Safety Commission. The government agency
which has the task of deciding whether or not a given product
is safe for 'general consumer' use.
Cruise A rocket which has failed in such a way that it ends up
Missile flying horizontally while still under power. A common
example would be a multi-stage rocket which stages "dirty"
(due to stability or structural problems) causing the upper
stage to bend to near horizontal at ignition. Severe launch
rod tip off or high winds have also been know to cause a
cruise missile attitude.
Davis Douche A method of igniting clustered motors by using a piece of fuse
in each motor with all fuses dropping into a pie plate that has
been dusted with black powder and taped to the bottom of the
model. A single ignitor in the black powder "flashes the pan"
igniting all the fuses at once. Developed in the early '60s by
Joel Davis and detailed in an early Model Rocketry Magazine
[late 1968 or early 1969, before they went to color covers].
Delay Train Pyrotechnic material in the rocket motor which burns slowly
Delay Charge between the propellant charge and the firing of the ejection
charge. This allows the rocket to coast towards apogee and
slow down to deploy the recovery system at low speed.
Double Base A solid propellant consisting of two monopropellants (usually
Propellant nitroglycerin and nitrocellulose) and various additives.
Double base propellants are used as smokeless powders in
ammunition. They are also used in smaller military rockets but
have been largely replaced by composites in larger vehicles.
Double base propellants are not used in hobby rocketry. See also
"Composite Propellant"
DQ Disqualified flight. See also "Midwest Qualified"
Drag A dimensionless number used in aerodynamics to describe the drag
Coefficient of a shape. This number is independent of the size of the object
(Cd) and is usually determined in a wind tunnel. It is part of the
basic drag equation F=.5*rho*V^2*Cd*A where F is the drag force,
rho is the air density, V is the air velocity and A is the cross
sectional area. All of these, except Cd, are directly measurable
in a wind tunnel so Cd can be thought of the "fudge factor" that
accounts for all of the aerodynamic peculiarities of a shape. The
Cd for most sport type hobby rockets is in the range of .4 to .5.
Drag Form The drag coefficient (q.v.) of an object multiplied by its cross
Factor sectional area. This is used to scale the drag value for a
(CdA) particular object from the dimensionless Cd. Theoretically, every
object of a similar shape will have the same Cd regardless of its
size meaning that both a grain of rice and a Zeppelin would be the
same. Multiplying by the area allows comparisons of the true drag
between dissimilar objects. For example, the original Honda Civic
had a horrible Cd, and makers of large luxury cars, with a little
edge rounding, were easily able to beat it and proclaim "Lower
drag than a Honda Civic!" in their ads. This is patently absurd
as the Honda had such a tiny cross section, thus much lower
*actual* drag. See also "Optimum Mass"
Drop Staging See 'CHAD Staging'
Effective See Impulse (Relative)
Exhaust Velocity
Ejection A device used in some rockets to eliminate the need to use
Baffle wadding to protect the recovery system. Usually composed of
some type of metal wool or mesh to absorb the heat of the
ejection gases before they reach the recovery compartment.
Ejection A small quantity of black powder used to generate gas pressure
Charge within the rocket to deploy the recovery system. This is
activated when the delay train (q.v.) burns through. On rockets
with electronic ejection timers, this may be a separate small
container of black powder which is triggered by a signal from
a timer or other control unit.
Electric A type of igniter originally designed to set off fuse-type
Match blasting caps (i.e. a match that can be set off from a great
distance electrically). It requires a very low electrical
current (~10 mA range) to activate.
Engine A machine that converts energy into mechanical motion. Such
a machine distinguished from an electric, spring-driven or
hydraulic motor by its consumption of a fuel (from *American
Heritage Dictionary*). See discussion at the end.
Estes Dent A semicircular deformation of the leading edge of the body tube
cause by the nose cone snapping back and striking the body at
ejection. The problem is intensified by short shock cords which
don't absorb as much energy before reversing and give the nose a
closer target with better aim :-) So named due to that company's
policy of providing very short shock cords in their kits.
Fillet A reinforcement of the joint between the fin and the body tube
of the rocket to improve the rocket's aerodynamics and to
strengthen the fin mount.
FIREBALLS An experimental rocketry/HPR launch hosted by AERO-PAC (q.v.)
which has since been superseded by NXRL (q.v.). The emphasis was
on VERY LARGE advanced rockets of "K" impulse or higher. The idea
originated with Steve Buck and the first launch was sponsored by
Bill Lewis of AERO-PAC. The name came from jokes surrounding the
event (e.g. "It takes BALLS to launch a rocket that big"). Steve
claims that it was never intended to mean "Big Ass Load Lifting
Suckers" as implied in early advertisements. Against the wishes
of its founder, "Fire" was placed in front of "BALLS" to placate
those few who had a problem with the name.
Fireballs was traditionally held the Monday after LDRS (q.v.),
but it was never formally a Tripoli launch. The 1992 FIREBALLS
(where 'Down Right Ignorant' was launched) was sponsored by
Tripoli for the purposes of insurance coverage, and after that
they decided to "adopt" the event with a name change.
Hang Fire Terms which refer to abnormal ignition. With hang fire, the motor
Misfire usually ignites after a considerable delay. Misfires never
ignite. Hang fires often appears as a misfire until the motor
ignites some time later. This is the main reason the safety code
advises not to approach a misfired rocket for one minute.
High Power a non-professional rocket weighing more than 1500 grams
Rocket(ry) at liftoff, containing more than 133 grams of propellant, or
(HPR) containing any combinations of motors with more than 160NS of
total impulse. High power motors go all the way to class 'O',
with over 40,000NS of total impulse. High power rockets require
an FAA waiver to launch. Tripoli defines a high power rocket
as those with over 40NS of total impulse (i.e., 'F' power and
above) and advanced rockets as those with more than 160NS total
impulse (i.e., 'H' power and above).
Hobby Rocket A general, collective term used to describe both model and HPR
rockets to differentiate them from amateur/experimental rockets.
The latter, while also non-professional, might better be called
"Obsession Rockets" :-)
HPR Lite A fairly new term used to describe rockets using motors in the
'E', 'F', and 'G' power classes. Formerly called "Medium Power
Rocket" (a term nobody used), it describes rockets which fall
between the current NFPA 1122 weight limit of 1 lb (~454 grams)
and the new proposed model rocket weight limit of 1500 grams.
Rockets in the 'E' through 'G' class aren't normally considered
high power rockets but, to be successful, must be built using
many of the same construction techniques as the larger rockets.
Also, any rocket over 1 lb requires an FAA waiver to fly legally.
HPRM High Power Rocketry Magazine - formerly *Tripolitan* (q.v.).
An independent magazine dealing with all aspects of consumer
rocketry, but with a definite emphasis on high power, advanced
and experimental consumer rocketry. Published six times a year.
A subscription is included with membership in Tripoli, but
can be had separately. Also available on newsracks in larger
hobby stores. Current editor: Bruce Kelley.
Hyperterminal A situation where a rocket is traveling faster than terminal
Velocity velocity (q.v.) for a given motor. This is possible, for example,
with a staged model with grossly mismatched motor combinations
such as an F-100 staged to a B6. At staging, the upper stage
will already be beyond its terminal velocity for the "B" motor.
In this case, the upper stage will actually *decelerate* during
thrust and approaches terminal velocity from above.
Igniter An expendable device used to ignite a rocket motor.
Impulse A measure of the efficiency of a rocket engine. Similar to
(Relative) Specific Impulse, it is defined as the Total Impulse (q.v.)
divided by the mass of the propellants. A little dimensional
juggling shows that this gives the same units as velocity
(ft/sec or m/sec) hence is sometimes called "Effective Exhaust
Velocity." How quickly the reaction mass leaves the nozzle is
a good measure of efficiency.
Impulse A measure of the efficiency of a motor/propellant system.
(Specific) It is determined by taking the Total Impulse (q.v.) and dividing
by the weight of propellants. This carries the potentially
confusing units of "seconds" (as if it had something to do with
the burn duration) but is due to weight and thrust both being
force parameters hence canceling out (e.g. lb-sec/lb or N-sec/N).
This is actually very handy since it makes the term independent
of the units system (metric or English) since they both use
"seconds" for time.
Impulse A measure of the total momentum imparted to the rocket by the
(Total) motor. It is defined (for those who know calculus) as the
integrated area under the thrust-time curve. For the rest of us,
it can be thought of as the motor's average thrust times the
duration of the burn. Measured in N-sec or Lb-sec.
Kato See "Cato"
Kicked A term used to describe a motor which is ejected from the
rocket while in flight. This often results in the failure of
the recovery system. It is usually caused by not fitting the
motor into the motor mount properly. See also "Prang"
Kitbash Taking two (or more) kits and combining ("bashing") them into
a new design. Often used as a contest event (Team Kitbash, where
teams compete, Kitbash Duration, Scale Kitbash, etc) where the
idea is to be creative in a limited amount of time.
Origin:
The term appears to have come from the model railroading hobby
where kits for buildings and other diorama items have, for
decades, been modified from their original intent to suit the
needs of a particular layout.
Krushnic A very dramatic phenomenon where your rocket makes a tremendous
Effect amount of noise and smoke but doesn't go anywhere! This happens
when the motor is recessed into the body tube by more than one
tube diameter. If so recessed, the cylindrical volume below the
motor forms a secondary expansion chamber which allows the
exhaust gasses to expand below atmospheric pressure before
leaving the rocket. Surrounding air aspirated into the exhaust
stream causes turbulence which negates much of the thrust, along
with creating the characteristic roar. A multi-stage model that
ejects its booster motor, but not the airframe, is a perfect
example. Very damaging; it almost always destroys the lower body
tube beyond use. Named for Richard Krushnic, the rocketeer who
characterized the effect in the late '60s. Not to be confused
with "Suction Lock" (q.v.).
Land Shark A rocket which has failed in such a way that it ends up on
Worm Burner the ground while still under power. Upper stages of unstable
multi-stage rockets often end up like this, as do some (too)
heavy HPR rockets with long-burning, low thrust motors.
Landis Loop A ring used in a tower launcher to keep the back end of a
egglofter centered during launch. Invented by Geoff Landis
and named for him by Bob Kaplow (Mr. "Dual Eggloft Forever")
LCO Launch Control Officer: the individual responsible for safe
operation of the launch range.
LDRS The annual national high power sport launch sanctioned by
Tripoli. LDRS stands for 'Large Dangerous Rocket Ships,' the
derivation of which is best left to others. Note: LDRS has NEVER
stood for 'Lets Do Rocketry Safely', despite what you hear from
historical revisionists trying to mollify public officials :-)
Lovelace A phenomenon where the nose cone is apparently "sucked" out of
Effect the body right at motor burnout. It is more prevalent on para-
bola, ogive and other low drag nose shapes. The theory (as yet
unproven) is that since the nose cone has much less drag than
the body, its momentum tends to carry it forward faster (or,
more correctly, the body's drag decelerates *it* more quickly)
putting tension on the nose-body joint. The condition is
exacerbated by any nose weights added for stability (which
also raise the momentum of the nose) and/or a loose fit of
the nose in the body.
Another possible contributing factor could be the denser air
(trapped in the body tube from ground level) exerting pressure
on the nose cone once the rocket reaches a higher altitude.
The term is named after an early 1970s movie actress
who, ahh, um...well, go ask your dad :-)
===[End of Part 1]===
|
| 33.16 | Glossary M-Z | VERGA::KLAES | Quo vadimus? | Wed Mar 02 1994 12:40 | 597 |
| Article: 15836
From: [email protected] (jack hagerty)
Newsgroups: rec.models.rockets
Subject: Glossary, M thru Z
Date: 26 Feb 94 09:25:02 GMT
Organization: Robotic Midwives, Ltd., Livermore, CA
Magnelite (tm) An ignitor made by Rocketflite used mainly to start composite
motors. A medium power device (2-3 amps at 12 volts), it requires
significantly more than an electric match (q.v.), but not as much
as a Copperhead (q.v.). It consists of a nichrome bridgewire
dipped in a magnesium based pyrogen which burns *very* hot
(~6000F), aiding in the ignition of stubborn composites, such
as a "Blue Thunder". They come both single and double dipped,
depending on how much "oomph" you need. The head is quite large
so they work best in 29mm and larger motors.
Medium Power See "HPR Lite"
Rocket
Midwest During the 1970's, NAR contest flyers circulated a persistent
Qualified rumor that meets held on the East Coast were held to a much
higher standard of flight qualification than those flown in the
Midwest. The Contest Board steadfastly maintained that contest
rules were uniformly enforced. The differences in flight
qualification occasionally surfaced at NARAM. If an RSO qualified
a flight that many people felt should not have been, his or the
flyer's geographical location came under scrutiny. While no rule
changes or procedures were modified, flyers continue to refer to
those marginal flights squeak through as "Midwest Qualified."
The term also gained popularity when a group of competitors from
the SNOAR section in Cleveland began offering at NARAM the
"Best Midwest Qualified Flight" award. A collection of wreckage
of NARAM's prangs, large and small, were attached to a large
sheet of cardboard, along with local flora, fauna, tourist
brochures, food wrappers, etc. SNOAR members then decided who
had the best prang of NARAM, and presented the "trophy" to the
"winner" at the awards banquet. Nomination was cause for pain
enough, but winning made one a legend in his own time.
Minimum A rocket built with the smallest possible diameter body tube for
Diameter the size of motor casing. Usually done to reduce drag in sport or
competition models even though it can increase the difficulty of
attaching fins and recovery systems. See also "Boosted Dart"
Model Rocket An aero-vehicle that ascends into the air by means of a
reaction motor, but without the use of aerodynamic lifting
surfaces. The gross launch weight, including motor(s),
will not exceed 1500 grams. Motor(s) for said vehicle will
not exceed 160 Newton seconds of impulse and/or contain more
than 62.5 grams of propellant each, and no more than a total
of 125 grams of propellant in multiple motor situations.
All components of said vehicle will be of wood, paper, rubber,
breakable plastic or similar material and without substantial
metal parts.
Note: Current NFPA recommendations (NFPA 1122) limit model
rockets to ~454 grams (1 pound) gross launch weight,
115 grams total propellant, and no motor with more
than 160NS of total impulse. The FAA requires a waiver
application and approval for any model over 1 pound.
The FAA is considering amending its FAR 101 to allow
models up to the current NAR model rocket definition
(1500 grams weight , 125 grams fuel...) to fly without a
waiver.
Model rockets in Canada are limited to 1 pound total
launch weight and 80NS of total impulse. The same
rules apply for construction materials as with US NFPA
guidelines.
Model The original NAR newsletter. Published as an insert to MRM
Rocketeer (q.v.) while it lasted and thus available to non NAR members
for a while. After MRM folded, it was again published stand-alone
and gradually expanded to a magazine style format. It became
*American Spacemodeling* (q.v.) in July 1984, although there
continued to be a section called "The Model Rocketeer" for the
NAR president's column and other association news (just like in
MRM!) which became the "President's Corner" in 1992.
Modroc Model Rocket. Also seen as 'modrocer', or similar spelling,
to mean 'model rocketry enthusiast'.
Monopropellant See "Single Base Propellant"
Motor Something that imparts or produces motion, such as a machine
or engine. A device that converts any form of energy into
mechanical energy (from *American Heritage Dictionary*).
See discussion at the end.
MRM Model Rocketry Magazine - An early attempt at a "newsrack"
style rocketry magazine. It attempted to do for rocketry
what *Model Railroading* did for that hobby or *RC Modeler*
did for model airplanes, namely create a forum where the whole
industry could talk directly to the hobbyist without limiting
him to a single company (e.g. the MRN or AR) or making him
join an organization (e.g. the NAR). What it actually proved
was how tiny the hobby was back then as it only lasted a bit
over three years from 10/68 through 1/72 then quietly folded.
Notable on the staff was a young Jay Apt, who went on to join
the astronaut corps and has made several Space Shuttle flights.
Despite the crude graphics and generally marginal production
values, the magazine was treasured by its small band of
followers and copies are in great demand today. Photocopies
are circulated by an "old boy network" at meetings and swaps.
While it lasted, it also incorporated *The Model Rocketeer*
the NAR newsletter which later became *American Spacemodeling*
and still later *Sport Rocketry* (available off the rack in
larger hobby shops). *HPR Magazine* (q.v.), the Tripoli journal,
likewise started as a captive publication for TRA which was later
taken private by its current editor. Thus we now have TWO
rocket hobby magazines on the newsracks today!
MRN The Model Rocket News - The oldest continuously published
rocketry periodical. Started by Vern Estes and his small
crew in 1960, it is still sent to all of Estes's active mail
order customers. Somewhat sophomoric in style, it contains a
great deal of practical information, especially for beginners.
It has survived a bewildering array of changes in format over
the years, but is still published three or four times annually.
Current editor: Mike Hellmund.
NAR National Association of Rocketry. A national hobby organization
promoting model and high power rocketry in the United States.
The NAR promotes rocketry related sport flying, competitions,
and education.
NARAM National Association of Rocketry Annual Meet. The NAR
national championships competition, held in August of
each year.
NARCON National Association of Rocketry Annual Convention. An annual
event sanctioned by the NAR oriented towards non-competitive
(i.e., sport) model and high power rocketry. It includes
seminars, R&D presentations and lots of sport flying.
NARTS National Association of Rocketry Technical Services. A service
provided by the NAR for both members and non-members. NARTS
stocks rocket plans, technical reports, and other items of
interest to rocketry enthusiasts. NARTS may be reached at
NAR Technical Services (NARTS)
P.O. Box 1482
Saugus, MA 01906
CompuServe account: 73320,1253
Newton & Metric units used to measure thrust and total impulse (q.v.)
Newton-second respectively. One pound = 4.445 newtons.
NSL National Sport Launch. An annual, national sport fly
sanctioned by the NAR. It is currently held in February
of each year so that it is midway between NARAM national
meets.
NFPA National Fire Protection Association. A private for-profit
organization responsible for crafting rules and regulations
dealing with fire safety issues which are beyond the expertise
of local agencies. The NFPA is NOT a government agency and has
no enforcement power of its own. It gathers experts in various
fields to write safety regulations for adoption by local fire
agencies (at the discretion of the Fire Marshal). The current
NAR Model Rocket Sporting Code was developed by the NAR and NFPA.
Both the NAR and Tripoli are members of the NFPA. G. Harry
Stine ('the old rocketeer') is currently the chairman of the
pyrotechnics committee of the NFPA.
NFPA 1122 The current NFPA regulation concerning model rocketry. The last
adopted regulations were enacted in 1987 and defined a model
rocket as being less than 1 pound in launch weight, containing
less than 4 ounces (~114 grams) of fuel, with no more than 160NS
total impulse in all motors, and no motor over 80NS of total
impulse. The NAR is currently working with the NFPA to update
the definition of 'model rocket' to agree with the current NAR
definition (see 'model rocket').
NFPA 1127 The current NFPA regulation concerning High Power rocketry.
[The remainder of this definition under construction]
NXRL The National Experimental Rocket Launch. An annual launch
sponsored by Tripoli and hosted by AERO-PAC (q.v.) for the
purposes of launching very large (K and above) HPR birds. An
outgrowth of FIREBALLS (q.v.), Tripoli "adopted" the concept to
provide insurance and continuity on an annual basis. The main
difference between NXRL and other Tripoli launches (e.g. LDRS,
Danville) are that no rockets *below* K power are permitted
(which holds down the crowd) and that home made motors are
allowed as long as they conform to the basic HPR safety code.
Ogive A shape defined by the intersection of two circles. It is not
the same as a parabola (q.v.). Both ogives and parabolas produce
low drag sub-sonic nose shapes. They can be told apart since a
parabola always has a rounded nose while an ogive comes to a
point.
Optimum Mass For any given motor and Drag Form Factor (q.v.) the liftoff
mass for which a rocket will reach maximum altitude in dense
atmosphere. At first this might seem to be just the lowest
possible mass, but there is a two edged nature to mass covering
both powered flight and coasting. Lower mass will give higher
burnout velocity, but will dissipate its momentum to drag faster
(think of a feather). Conversely, a heavier rocket will have
more momentum at burnout to coast farther, but too much mass
will hold down both burnout altitude and velocity. Hence, there
is a "knee" on the liftoff mass vs. altitude graph.
For very low impulse motors (say "B" and below) this "knee" is
right around the mass of the motor itself, so the rule of thumb
is "the lighter the better." The higher impulses, though, have
more leeway, and careful calculations should be made to determine
the optimum mass for altitude attempts.
In a multi-stage rocket with no staging delays, only the dead
mass in the upper stage participates in coasting. Extra dead
mass in lower stages cannot enhance coast distance, and so
lower stages should be as light as possible. Strictly speaking,
an undelayed staged rocket has no optimum liftoff mass, but
the mass of the last stage may be optimized with respect to the
(sub-optimal) lower stages. In dense atmosphere, the best single
stage configuration is more efficient than the best multi stage
configuration, provided all the propellant can be contained in
one stage. Indeed, there are many instances when cluster rockets
out perform staged rockets.
The opposite is true for rockets operating in the thin atmosphere
of high altitudes. In that environment, staged rockets are more
efficient (propellant-wise) than single-staged rockets, and
lighter rockets always perform better. There is no optimum mass
in a complete vacuum.
Pacific An experimental rocket organization which experiments with
Rocket amateur rockets both solid and liquid fueled, although mostly the
Society latter. It is a very old organization by hobby standards with
(PRS) roots dating back to the '50s thus predating hobby rocketry in
its current form. They launch in the Mojave Desert from facili-
ties leased from the Reaction Research Society (q.v.).
Parabola A shape produced by the formula y=x^2. Used to produce low
drag nosecones. See also "Ogive"
Payload Anything carried aloft by the rocket that is not part of the
rocket itself. Common payloads include altimeters, computers,
cameras, and radio transmitters. The Safety Code specifically
prohibit the launching of live payloads.
Phenolic A heat-resistant plastic most familiar as the material from which
plastic ashtrays are made. It is made by a reaction of phenol
and formaldehyde. When mixed with carbon black, it is used to
make casings for composite propellant rocket motors. It is also
used to reinforce the cardboard in body tubes for competition
rockets (e.g. "Blackshaft" tubing sold by Apogee). Phenolic body
tubes are stiffer than ordinary tubes, but are also more brittle so that extra care must be taken to avoid damage during
construction, transportation and recovery.
PMC Plastic Model Conversion. The term used to describe a plastic,
static model of some type (typically an aircraft, rocket or
spaceship) that has been converted to fly as a model or
high power rocket. This term is also used as an abbreviation
for an NAR-sanctioned competition using converted models.
Prang Term describing a failure mode whereby a rocket comes down
aerodynamically stable, in other words, 'streamlines in'. This
is almost always caused by some sort of recovery system failure,
usually the result of a too-tight nose cone, too-tightly packed
parachute or a too-loose motor that ejects out the back. Multi
stage models with upper stage ignition failures also result
in a prang.
The results of a prang range from no damage at all (other
than a few grass stains) on lightweight sport models to
the total destruction of the rocket (usually a payloader
with a VERY expensive payload on board :-(.
A prang that occurs while the motor is still burning (e.g.
a marginally unstable rocket that performs one very large
half loop) is called a 'Power Prang'.
Origin:
If you insist on it being an acronym, the postwar military
sounding rocket program had a quasi-official failure mode
category "Parachute Recovery Apparatus No Good." However, like
CATO (q.v.), this is another "Post Hoc" definition. The term was
in widespread use during WW II in aviation circles to describe
aircraft crashes, especially experimental or military ones. Prior
to use in the U.S., it was popular in Britain since at least the
'30s where the expression "Prang his Kite" was equivalent to our
"Auger in" or "Buy the Farm."
RASP The Rocket Altitude Simulation Program. Originally written by
G. Harry Stine in BASIC in the late '70s (and included as an
appendix in the later editions of the Handbook), it performs a
simulation of rocket flight using small time interval approxima-
tions. The original was relatively primitive assuming constant
Cd, vertical flight and other simplifications. There have been
several rewrites into "C" and other languages to both broaden
its appeal and increase its sophistication.
Reaction One of the oldest amateur rocketry organizations. Founded in
Research 1943, members of this Southern California group investigate all
Society forms of reaction based vehicles: solid/liquid/hybrid. Their cur-
(RRS) rent very ambitious plans include orbiting the first *completely*
amateur satellite with a vehicle based on the "10K" (10,000 lb
thrust) LOX/Kerosene motor now in development.
They have the decided advantage of *owning* their Mojave desert
launch site which is adjacent to Edwards Air Force Base and thus
protected by their "infinite" restricted airspace. They lease
the use of their launch facilities to the Pacific Rocket Society
(q.v.) and welcome HPR fliers to come down and fly anything as
big and high as they want as long as it's 1) prearranged and
2) you play by *their* safety procedures. For more info there is
a message on the Pacific Energy voice mail system which can be
accessed after 6 PM (Pacific time) on weekdays and any time on
weekends (213) 725-1139, ex 777. PR co-ordinator: Niels Anderson.
Red Baron A boost glider which has tangled with the streamer or
parachute of the booster pod. The entire model tends to
nose dive into the ground, like a WWI airplane which has
just been shot down.
Reef A series of techniques used to gather the shroud lines of a
parachute together to prevent it from fully opening. This is
usually done on rockets that reach extreme altitudes or launched
on windy days which need higher sink rates to help them land
near the launcher. There is also a "traveling reef" technique
of placing a soda straw or metal washer on the shroud lines and
sliding it all the way up to the chute canopy during prep. At
deployment, the parachute is prevented from opening until the
chute is fully deployed and the rocket stabilized beneath it. The
straw/washer then slides down the shrouds allowing the canopy to
open gradually. This is used mostly on large rockets which might
have very high speed or high altitude recovery deployment since
it allows the rocket to slow and drop considerably before chute
opening.
Reynolds A dimensionless number used by fluid flow engineers to character-
Number (Rn) ise the way a fluid (gas or liquid) will behave when passing
over a solid surface. The number combines the fluid's density,
viscosity and velocity with the length it's traveled along the
surface. No matter what the fluid is or what size the surface,
the flow conditions (laminar, turbulent, detached, etc.) should
be the same at the same Rn. Discovered by Osborne Reynolds in
the 19th Century while studying the flow of water in pipes and
channels, it has proven most useful to aerodynamic engineers and
naval architects in scaling up wind/water tunnel test results to
full size.
Carl Dowd, a model aviator and NASA engineer, found it helpful
to think of Rn as the "coarseness" of the air seen by a body.
Move the body faster, and more particles will pass over it in
a given unit of time, increasing Rn. Make the body larger, and
there will be more particles over the body at any instant,
increasing Rn.
R/G Rocket glider. A glider which is boosted to altitude by a
rocket. The entire model glides down together. No part of the
model separates, as in a boost glider. Technically, an R/G is
a particular form of B/G.
RMS(tm) Reloadable Motor System. The trademarked name of the AeroTech/
ISP reloadable motors. Often used (incorrectly) as a generic
name for all reloadable technology.
Roman Candle A failure of the motor restraint (thrust ring or engine hook)
where the rocket stays on the pad while the engine flies out of
the body (pushing the nose cone and recovery system ahead of
it). Sometimes mistaken for a CATO (q.v.).
RSO The Range Safety Officer, the individual responsible for
ensuring that rockets presented for launch are properly
constructed, prepped and balanced for stability.
Shred A model which has lost one or more fins due to aero loads
and/or acceleration. Also used to refer to a model which has
completely come apart during takeoff. Can be used as either a
verb or noun. See also "Strip"
Silver A black powder motor, made by Rocketflite, Inc., which produces
Streak(tm) a large plume of sparkling exhaust when ignited.
Single Base A solid propellant based on a single monopropellant. In
Propellant practice usually nitrocellulose in a mixture with stabilizers
and plasticizers. Single base propellants are used as smokeless
powders in ammunition. In rockets, such propellants have been
largely replaced by composites. Single base propellants are not
used in hobby rocketry. See also "Composite Propellant"
Solar Estes Industries brand of Igniter. Made from two wire
Igniter(tm) conductors with a piece of Nichrome wire connecting them at
one end. The nichrome wire tip of the igniter is dipped in
a pyrogenic compound which flares to ignite the rocket motor.
Spill Hole An opening cut in the top of a parachute to increase the
sink rate (thus decrease drift distance) and aid recovery
on windy days.
Sport The journal of the National Association of Rocketry.
Rocketry Previously known as *American Spacemodeling* (q.v.). Published
six times per year. Distributed as part of membership to
all active NAR members but also available off the rack in
larger hobby shops. It has no connection with the CompuServe
discussion group of the same name. Current editor: Steve Weaver.
Squib A small explosive device used to detonate larger explosive
charges. While the term is sometimes used to describe igniters
used in hobby rocketry, especially HPR igniters such as electric
matches (q.v.), true squibs are almost *never* used as igniters
since their purpose is to set up a detonation pressure wave to
set off pressure sensitive explosives (e.g. plastic explosive),
while an igniter must start a (relatively) low speed flame front
so that the motor burns, rather than explodes.
String Test A simple method for testing the stability of a model. A string
approximately 10ft long is tied to the center of gravity of a
fully prepped rocket which is then twirled overhead in a circle.
If the nose points in the direction of the spin and the rocket
does not wobble then it is very likely a stable design.
The string test is not very reliable IMHO since it introduces
another component, namely radial acceleration, that is completely
absent in normal flight. When you tie the string to the rocket
at the CG, it's not really at the CG but attached to the outer
surface of the body tube *above* the CG (which is actually inside
along the center of the tube). In order for the rocket not to
twirl, the projection of the string has to pass through the CG.
This is fine as long as the rocket is moving in a linear fashion.
But when you start swinging it, it's no longer moving linearly,
but being constrained to a circle. This forces the rocket (if
it's stable) to assume an angle of attack in order to keep
pointing into the "relative wind". This angle means that the
projection of the string no longer passes through the CG, but
slightly behind it. You have to move the string slightly forward
for the string to point through the CG while you swing it.
Strip Terms describing a parachute that has had one or more shroud
Stripped lines pull free due to opening shock. Usual cause is recovery
deployment at too high a speed, but can also be due to age (of
the tape disks on a plastic chute) or poor construction. Can
be used as a verb or noun. See also "Shred" and "Reef"
Suction Lock The Mother of all Base Drag. See "Bernoulli Lock"
Terminal In the powered phase, the speed where the motor thrust equals
Velocity the combined forces of gravity and aero drag. Theoretically, the
rocket would continue ascending at a constant speed (i.e. no
acceleration) with these forces in balance. This doesn't actually
happen since motor thrust varies with time and aero drag with
altitude. A second meaning is, when descending, where aero drag
balances the weight of the descending model. If under a 'chute
or other high drag recovery aid, this is quite slow. If in core
sample (q.v.) mode this speed can be several hundred feet/sec.
See also "Hyperterminal"
Thermalite A material, originally used to detonate plastic explosive, which
burns at a controlled rate and high temperature. Used with rocket
motors as an ignition enhancement. It can be ignited by electric
(nichrome) means, flash bulbs or the exhaust of a previously
started motor. It comes in three burning speeds color coded as
pink (slow), green (medium) and white (fast). For a rough order
of magnitude, slow is around 1/2 in/sec and fast is 2 1/2 in/sec
in free air, but this can be affected by temperature, humidity,
pressure and whether or not the fuse is sheathed in a tube.
Tiger Tail(tm) An igniter sold by Quest Aerospace consisting of two very
thin copper foil leads separated by and even thinner plastic
insulator with the pyrogenic compound at the tip. Essentially
a mini Copperhead (q.v.), its name comes from the orange and
black striped tape strip provided to allow it to be used with
ordinary alligator clip ignition systems.
Time Delay See "Delay Train"
Triple Base A solid propellant based on three monopropellants and additives.
Propellant In practice, the monopropellants are usually nitroglycerin,
nitrocellulose, and nitroguanidine. In military rockets,
such propellants have been largely replaced by composites.
Triple base propellants are not used in hobby rocketry. See
also "Composite Propellant"
Tripoli Tripoli Rocketry Association. A consumer rocketry organization
(TRA) founded to promote the interests of high power and advanced
rocketry enthusiasts.
Tripolitan *The Tripolitan...America's High Power Rocketry Magazine*
The bimonthly journal of the Tripoli Rocketry Association,
published until July/August 1992. It became *HPR Magazine*
(q.v.) with the Sept/Oct 1992 issue).
Through The An HPR fin attachment technique which provides much greater
Wall (TTW) strength than the typical surface mount used in model rocketry.
To use TTW, slots are cut in the body tube where the fins mount
and the fins are built with extended tabs on the root edge which
fit through these slots. In one form of TTW, the tabs are
short and just provide a surface to build up epoxy fillets on
the inside as well as the outside. In a stronger version of TTW,
the tabs reach all the way to the motor tube where they are
glued forming a very rigid box structure.
Wadding Any flame retardent material used to prevent the scorching of
the recovery system do to the heat of the ejection charge.
The material (usually a boron treated paper tissue) is placed
in the body tube between the engine and the recovery system.
See also "Ejection Baffle"
Waiver The term used to describe the official permission given by the
FAA allowing rockets with more than 4 ounces of fuel or weighing
more than 1 pound to be flown into FAA controlled airspace.
Woosh The humorous, genderless, politically correct way to refer to
Generator the propulsion device in a hobby rocket; thus avoiding the
great motor/engine debate (see discussion at the end).
YABAR Yet Another Born Again Rocketeer.
Zipper A devastating side effect of mounting the shock cord to the motor
Effect mount (which is often done for strength or to anchor a piston
ejection system). If strong and thin cord is used (e.g. Kevlar)
and the recovery system opens at too high a speed and/or the
piston comes all the way out of the body, then the line can "zip"
open the body tube all the way down to the motor mount :-( A
sufficiently strong top mounted shock cord can partially zip a
body tube if opened at a high enough speed.
--------------------------------
And the final burning question: Is the proper term rocket 'engine' or rocket
'motor'? Some thoughts from Buzz McDermott:
I don't know. I don't really care. And neither should you! In this
hobby 'motor' and 'engine' are taken to mean the same thing and both
refer to "the thing in the rocket which makes it go 'whoosh!!' (or 'roar',
if flying high power :-)". If you want a sure way to start a fight with
a fellow rocketeer, just argue that whatever term he/she uses is the wrong
one!
While I think Buzz's response reflects the correct attitude to the question,
the subject comes up often enough that a real definition is required. The
difficulty comes since there are several "real" interpretations of the terms
involved. The following discussion is intended for the purposes of education
only to clear up some of the rampant misunderstandings seen periodically. It
should not be used to start flame wars :-) I think that by the end, you'll see
that the subject is complicated enough that *either* term is perfectly
acceptable. And, no, I'm not weaseling out on this one.
From a mechanical engineering standpoint, "motor" is the more general term.
It is defined as anything that imparts mechanical motion (hence the name).
"Engine" is more specific and despite its Roman origins (where it meant
mechanical weapons of war and "Engineer" was a military rank) the commonly
accepted definition today is "A device which creates mechanical force (rotary
or linear) by means of a mechanism converting stored chemical energy through a
thermal process." In other words, a heat engine. Look up Carnot.
Thus we have internal combustion engines (gasoline, diesel, etc) which do
the thermal conversion right in the mechanism itself; external combustion
engines (steam, Stirling, etc) where the thermal conversion takes place
outside the mechanism and the heat is transferred by a working fluid; and
continuous combustion engines (gas turbines) where the various cycle phases
(mixing, compression, combustion and expansion) are separated by distance
along the engine rather than by time.
Electric motors are called such because even though they do an energy conversion
by means of a mechanism and have a mechanical (rotary or linear) output, there
is no consumption of fuel and no thermal component to the conversion.
Jets and rockets get into a gray area, though. Turbojets, such as used on
airliners, helicopters, etc., are clearly engines. While they don't use a
mechanical device for the thermal expansion (e.g. a piston) they do have
mechanical compressors and power take-offs in major support roles. However, it
is possible to make a jet with no moving parts, e.g. a ram jet.
Likewise, the "whoosh generators" we use in the hobby are clearly motors. While
they do consume a chemical fuel and produce thrust by a thermal conversion,
there is no mechanism, no moving parts at all except the exhaust itself. Liquid
fueled rocket "engines" are less clear. True they have propellant pumps, valves
and lots of other moving bits, but their support roles are much less central
than the compressors on a turbojet. You can build a liquid fueled rocket without
pumps at all, as Goddard and many amateurs have shown (see "Hyper for Hypergols"
in the Jul/Aug 93 HPRM for an example). This limits you to comparatively low
propellant flow rates, however, and pumps are used to enhance the process.
Generally, the sheer volume and complexity of the mechanism on a modern rocket
(e.g. a Titan or the Space Shuttle) award it the term "engine."
The above discussion, though, is rooted in the past. In our modern, information
society we have "compute engines" and "graphics engines" to reflect the
expanded role these devices play in our daily lives. Accordingly, the term
"engine" has been broadened considerably and a current definition is "a device
to effect a desired outcome" which pretty much covers everything. From this
point of view, "engine" is the superior of the term "motor." If you consider
that the "desired outcome" of flying our rockets is to put them high in the
air then a "rocket engine" is the device to effect it.
I think that you should find enough information here to defend either position!
========================
|
| 33.17 | Sending a ten-pound payload fifty miles up | MTWAIN::KLAES | Keep Looking Up | Mon May 23 1994 18:24 | 76 |
| Article: 1929
From: [email protected] (Brian Reynolds)
Newsgroups: sci.space.tech,rec.models.rockets
Subject: Re: Amateur rocketry
Date: 20 May 1994 13:58:34 -0400
Organization: PANIX Public Access Internet and Unix, NYC
In article <[email protected]>,
Ryan Pehrson <[email protected]> wrote:
>I have been involved in model rocketry for a long time. I got into
>some more advanced stuff about a year ago.
>
>I recently built my first rocket by myself...It ended up being about
>six feet tall. I made it out of high-strength carbon-fiber material.
>The motor system was a dual stage system, using high power, short
>duration solids on the bottom stage to get it really going (I used a
>system that is reusable - metal casings that you fill with your own
>solid propellant [which is dangerous, don't do it if you don't know
>how!] I used composite-based rather than gunpowder-type solids.) The
>class rating was H [a measure of pounds of thrust] for the two-motor
>first stage. The four-motor second stage was rated at G, but the
>power was distributed more evenly over a longer period, rather than
>right at the beginning.
>
>Anyway, it was quite an event. I had a basic telemetry system aboard.
>I alerted the nearby Air Traffic Control center and everything. The
>_Endeavor_ (my rocket) achieved at least Mach 1 on the way up, very
>possibly more. Unfortunately it disintegrated and the pieces went
>everywhere sometime during the second-stage burn. I estimate it got
>to a little short of 20,000 feet.
>
>My question is, how possible is it, if I built it stronger, added more
>power, made it bigger, to achieve LEO? Which is what, fifty miles?
>Would it be possible (and legal) for me to do so? With the basic
>materials I use for constructing a six-foot rocket?
>
>[Mod Note: LEO is 7.2 km/sec away, which is a neat trick with a one
>stage solid fuel rocket. Delta V = g * Isp * ln(Mr) ...
>Space is 100km, somewhat easier. Note that you start to run afoul of
>various government agencies getting into rockets that size range,
>including the BATF (that _is_ a destructive device, my friend, warhead
>or no...). Tread lightly into big rockets and talk much to those
>already doing them. -gwh]
I just happen to have a copy of the April 1994 issue of High Power
Rocketry here. One of the articles is "The World's First Amateur
Space Shot" by Duncan Cumming and George Morgan. It is the first of a
four part series. They describe a project to fly a ten pound payload
to an altitude of at least 50 miles. The Pacific Rocketry Society is
building the rocket (SPACE-FARER X80) with financing from the National
Space Society. The payload includes a Rockwell GPS receiver, a
fluxgate magnetometer, an accelerometer, an altimeter, pressure and
temperature sensors, a video camera with an amateur TV transmitter and
an 8mm movie camera. Two different rockets (one described as a
"sort-of mini Saturn S4B stage" using liquid oxygen and alchol and the
other a tandem tank design using nitric acid and turpentine with a
solid fuel booster) are being built to ensure that one of them will
achieve the project goals. The first article describes the payload.
The other articles will describe the design of each of the rockets,
and a post-flight report.
The previous issue of HPR had an article by Dave Crisalli describing
PRS's work with liquid rocket engines. Propulsion Research Laboratory
and Pacific Rocketry Society advertise videos and technical reports on
these engines and the rockets they've flown.
You might want to talk to the folks over in rec.models.rockets (note
crossposting) for more information.
--
Brian Reynolds | "But in the new approach, as you know, the important
[email protected] | thing is to understand what you're doing rather than
NAR# 54438 | to get the right answer."
IPMS# 30162 | -- Tom Lehrer
|
| 33.18 | | SKYLAB::FISHER | Carp Diem : Fish the Day | Tue May 24 1994 13:15 | 5 |
| Geez, I wish I knew where this guy lived so I could be sure not to live near him
(or at least his launch site). Note he does not say anything about how we
planned to recover this beast had it not disintegrated?
Burns
|