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| Title: | Welcome To The Radio Control Conference |
| Notice: | dir's in 11, who's who in 4, sales in 6, auctions 19 |
| Moderator: | VMSSG::FRIEDRICHS |
|
| Created: | Tue Jan 13 1987 |
| Last Modified: | Thu Jun 05 1997 |
| Last Successful Update: | Fri Jun 06 1997 |
| Number of topics: | 1706 |
| Total number of notes: | 27193 |
1255.0. "Kites make excellent glider launchers on windy days." by HPSRAD::AJAI () Mon Nov 12 1990 10:38
One more plea to stay the execution order, and perhaps revoke it
unconditionally :-).
I used to build and fly kites since I was 3+, and like my 2 hour
marathon flying session with the FS, there was a time when I used to be
soo hung up on kite flying that I used to do it in moonlight!
Muuuch later, (10+ yrs), while I was pursuing aeromodelling in
parallel, I designed a contraption that would release paper planes,
pieces of paper, what-have-you. To further digress, much to Alton's
consternation :-), what I did was to build upon a scheme given in an
old issue of the Scientific American (The Amateur Scientist column?).
In that article, the author had presented a scheme wherby a release was
fixed to the string near the kite, and the release held the object to
be dropped from a height. You proceeded to fly the kite to the desired
height of release, then sent up a paper cone along the string that
would strike the mechanism and cause it to trip, releasing the object.
While my elder brother tried this approach when I was a toddler (and I
had observed it), I did not bother trying it myself, until a decade
later when I had figured out a _much_ better scheme. I modified the
design so that the contraption could freely ride between two
pencils/dowels fixed about 3 feet apart on the string with clove
hitches. You flew the kite up to load bearing altitude, then fixed the
dowels and slung the contraption in between the sticks. Then payed out
the string so the object+mechanism rose with the kit to release
altitude.
Upon stabilising at release altitude, you merely jerked the string
hard. Due to inertia of the device, it would remain stationary wrt
earth, while the string with the dowels slide through, until the upper
dowel hit the mechanism and tripped it, releasing the object!!!!
The lower dowel served merely to prevent mechanism from sliding back as
you payed out the string.
The funny thing is, I was always captivated by the idea of using a kite
to release object (mainly planes and parachutes) from a height, and
when it all became clear to me as to how to do it - and this was verry
late in the evening - it was as though I was on fire! I quickly set
about soldering the mechanism to-gether from bicycle spokes and tinned
wire.
By the time I got done, the moon had come up. I got my kite flying from
the terrace of my home in New Delhi, and put on the contraption after
hitching the pencils in place. I used a strip of paper with a hole
punched in one end as my object. Payed out the string, and since the
moon was the only source of light, got the contraption high enough so
the moon was right behind it, "illuminating" it.
Then came the moment of reckoning. I jerked the string, and sure
enough, the piece of paper released and fluttered down. I was
triumphant. I was jubiliant. My idea had worked. Besides, I could
control the exact instant of release since the jerk determined relese
time!!! Only my RC soloing moment comes close in terms of euphoria.
In the months that followed, I released all sorts of things, including
leaves! Folded paper gliders were a favourite, and I had one that flew
over 1/2 a mile!
A few years later, I entered it for an invention talent contest in my
state, and won the 2nd prize! Yeah, man, I wuz on a roll - It got me
Rs. 300, which in those days was approx equivalent to $45.
Anyhoo, all this gives me an idea. Well Alton, here is a good reason
for giving this note a permanent home - let us put this under GLIDER
LAUNCHING TECHNIQUES! In fact, I am going to try this next year. It
might be even better than aero towing.
I'll have to stitch muh'self a parafoil first. Boy! One more thing to
do during winter...
ajai
| T.R | Title | User | Personal
Name | Date | Lines |
|---|
| 1255.1 | Dixie messagers | ZENDIA::REITH | Jim Reith DTN 226-6102 - LTN2-1/F02 | Mon Nov 12 1990 10:47 | 9 |
| Re: .11
I did the same thing using dixie cups travelling up the string. The big
problem is that the release is already down wind. Lots of fun on a "kite
string" budget ;^)
Al,
This thread is also being covered in Physics but it is getting weighted
down by defining the problem/question.
|
| 1255.2 | Altitude saves the day! | HPSRAD::AJAI | | Mon Nov 12 1990 12:01 | 17 |
| re -.1,
Jim,
Yeah, your dixie cup=paper cone that I referred to.
Downwind release is no problem _provided_ you have altitude to burn to
get back up wind. Also, since the kite flies higher with the string
nearer vertical [read: plane releases closer to you], the launch point
"corrects" itself [if not completely] in the right direction with
increase in prevailing wind speed.
If only I can find some volunteers :-) What the heck, I might as well
build that Sophistaced Lady that I won at the CRRC raffle 2 yrs ago...
ajai
|
| 1255.3 | Third world missile launching technology | HPSRAD::AJAI | | Mon Dec 03 1990 16:16 | 73 |
| <----------------- 6" ----> dimensions are approximate
<------ 4" ----> and not critical
A B C
This end 0 0 0 <-- Kite thread through these
towards | | | loops
ground | +------------------+
| | |
+----------0------------------0-+
X | | |
| | |
| | |
Y | | |
Spoke thread---> --0------------------0-+
this end
gives added
friction preventing
accidental opening.
All loops in wire shown as "0", which should be made
PERPENDICULAR to drawing.
Make loops A, B, C "open", i.e. coil the wire around a former
- as though forming a spring with just one turn, and with a
gap (similar to a loosely wound spring). The idea is to be
able to insert the kite string into loop by making string
perpendicular to drawing/device, and sliding through said
opening - SO YOU DON'T HAVE TO CUT THE STRING to affix
device.
By bending the XY member so it is at an angle to the drawing,
(with X in plane of drawing) and making it out of thinner
guage piano wire, you can add friction to prevent easy
opening. The location of the threaded end of spoke indicated
in drawing also serves identical purpose. You could bend
squiggles into the end of the wire to achieve the same
purpose as spoke threads.
Fly kite to load bearing altitude before affixing device.
Either end A or C may be towards the kite. However, depending
on whether the object is a deadweight (parachute) /floats in
the wind (glider), using it with end C/(or A) towards kite
will allow *IMMEDIATE* release upon device _barely_ opening.
IF you are not' fussy about instanteneous response (i.e.
willing to jerk string more than once), then this is a minor
detail.
Remember that this device is hooked between two
dowels/pencils held 2~20 times AC apart on the kite string.
You tie these on with clove hitches, so you don't mess up the
string permanently/painfully. 2AC separation gives you
release with a minor jerk, while 20AC or more separation
between the dowels will need a mega jerk - sometimes even to
the extent of having to pay out the string, stopping it, and
_subsequently_ jerking, to make the device "climb" the 20AC.
So why do all this? Well, as you fly your kite out to payload
launch altitude, you might inadvertently jerk the string, and
release the object prematurely. You can avoid this by
increasing the inter-dowel distance (which is akin to the
dead band of a servo, if you will).
Practice with a dummy before trying to use the real thing for
the payload. A strip of paper /leaf with a hole punched in it
is a good start.
And let me know how things work out.
ajai
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