Conference 7.286::space

913.0. "Black Horse Rocket Space Plane" by MTWAIN::KLAES (Houston, Tranquility Base here...) Tue Jul 05 1994 16:50

Article: 2397
From: [email protected]
Newsgroups: sci.space.tech
Subject: Black Horse and Usenet
Date: Thu, 30 Jun 94 09:38:42 MST
Organization: CRL Dialup Internet Access
 
[Mod Note: Mitch mailed this to me and we've discussed how to get his
messages posted, which probably will be in the same manner.  I am looking
forwards to more contributions from him and other active professionals
in the field -gwh]
 
    Hi.  It looks like my original posting got onto the bulletin board 
    okay, but unfortunately I had to hand-type it via Bix.  Spending any 
    time or uploading any significant data to sci.space.tech would get 
    prohibitively expensive in short order.
     
    I'm working here to try to figure out how to get a newsreader program 
    that will work alongside the ftp and telnet I already have on my PC 
    here at Phillips Lab. SO far, no luck.  If you have any suggestions I'd 
    be eager to hear them.
     
    I gather from the tone of the postings in the thread I read that Black 
    Horse has been discussed previously.  Is any of that stuff archived? 
    How can I get it?
     
    Last Wednesday Black Horse was briefed to the Chief of Staff of the Air 
    Force.  It looks very good for getting a program going.  We are trying 
    to target Oct 1997 for first flight.
     
    Mitchell Burnside Clapp
    [email protected]
    
    Here's a copy of the short paper.
    
    Aerial Propellant Transfer to Augment the Performance of Spaceplanes
    Captain Mitchell Burnside Clapp
    Phillips Laboratory, Kirtland AFB, NM 87117
    William Nurick, Frank Kirby, Ed Nielsen, Robert O'Leary, and Ray Walsh
    W. J. Schafer Associates, Inc., Calabasas, CA 91302
    and
    Daniel P. Raymer
    Conceptual Research Corp., Sylmar, CA 91392
    
    Abstract

    In-flight propellant transfer to a rocket-powered aircraft permits it to 
    achieve orbit with relatively little propellant compared to taking off 
    fully 
    loaded from a runway. The weight of many key components, such as wings and 
    landing gear, is substantially reduced. The vehicle takes off like a conven
    tional aircraft under rocket power from two of its seven engines, using jet 
    fuel (JP-5) and a non-cryogenic oxidizer (H2O2). After rendezvous with and 
    propellant transfer from a tanker aircraft, the vehicle lights all its 
    engines, accelerates to high speed, and pulls up into a steady climb into 
    orbit.

    Non-cryogenic, non-toxic propellants permit the propellant transfer to use 
    existing tankers, and a small aircraft similar in size to an F-16 could dem
    onstrate the capability and achieve orbit. Many important military missions 
    could be performed by such an aircraft. The concept is sufficiently simple 
    that relatively little in the way of new facilities or support equipment is 
    required.

    Introduction

    The mass of a single stage rocket vehicle at the beginning of its mission 
    Mo 
    is related to the mass at the end of the mission Me by the rocket equation:

    Mo/Me = exp(Dv/Isp g)

    where the symbol Dv represents the required mission velocity change, 
    including losses due to aerodynamic drag, gravity, back pressure on the 
    engines, steering, and so forth, Isp is the specific impulse of the engine 
    in a vacuum, (defined as the number of pounds of thrust per pound per 
    second of 
    mass flow through the engine), and g is the acceleration of gravity at 
    Earth's surface, which appears in the equation to convert mass to force so 
    that the argument of the exponential is dimensionless.
    Single stage to orbit flight is technically challenging because the *v 
    necessary to achieve orbit (30,500 ft/s, typically) imposes mass ratios 
    that are difficult to achieve with current structural technology. The usual 
    approach is to seek more energetic propellants with high Isp values. 
    Airbreathing approaches are also an attempt to achieve large Isp. This tends
    to involve propellants that are not very dense and difficult to handle, such
    as liquid hydrogen, or impose surpassingly difficult design and operations 
    problems such as those that have afflicted the National Aerospace Plane 
    program.

    Single stage rocket vehicles fall into three principal configuration 
    categories: vertical takeoff/horizontal landing, such as the SSTO/R vehicle 
    proposed by the NASA Access to Space Study, vertical takeoff/vertical 
    landing, such as the McDonnell Douglas Delta Clipper design, and horizontal 
    takeoff/horizontal landing, such as the Boeing RASV or British HOTOL 
    designs. 

    Between the first two of these, there is no obvious distinction in terms of 
    empty weight. Credible design studies appear to give similar weight 
    estimates for similar vehicles. Horizontal takeoff and landing vehicles, 
    however, tend 
    to be much heavier for a given payload because of the unique requirements 
    imposed by runway takeoff. Wing loads at rotation and the weight of landing 
    gear are of particular concern. Generally horizontal takeoff and landing 
    vehicle designs tend not to be pure single stage to orbit, but rely instead 
    on sled launch or auxiliary boosters to reduce gross weight.

    The purpose of this paper is to discuss another approach for operating 
    spaceplanes off conventional runways with conventional facilities: using in-
    flight propellant transfer to reduce the takeoff gross weight of a rocket 
    powered aircraft, and hence its size, weight, and cost. This is not an 
    attempt 
    to solve the rocket equation problem by means of increasing Isp, but by 
    decreasing Dv. Beginning the mission to space from tanker altitude and 
    airspeed reduces the amount of propellant that must be expended overcoming 
    drag and gravity losses. The emphasis is on maximizing the use of existing 
    components and keeping the design as simple as possible. Hence, we will use 
    existing tankers, landing gear, and conventional technology as much as 
    possible and examine the resulting size of the vehicle. A contracted six-
    week study between Phillips Laboratory, WJ Schafer Associates, and 
    Conceptual 
    Research Corporation developed this concept further.  The ground rules for 
    the study were:

    Horizontal takeoff like an aircraft
    Two engines firing at takeoff
    Propellant transfer at 40,000-43,000 ft
    Hydrogen peroxide and jet fuel propellants
    Power-off landing
    LEO mission
    Throttling during propellant transfer
    Maximize use of existing facilities and support equipment
    Conservative design assumptions
    Tanker aircraft selection

    In-flight refueling is commonplace in the US Air Force and Navy today. Two 
    systems are used: the Navy's probe and drogue system and the Air Force's 
    boom 
    refueling system. The probe and drogue system requires the pilot of the 
    receiver aircraft to do all the work, and transfers about 250 gallons per 
    minute. The boom system requires some cooperation between the boom operator 
    and 
    the receiver aircraft pilot, and can transfer 1200 gallons per minute. The 
    boom refueling system was selected for this design because of its high rate 
    of propellant transfer.
    Two types of tankers use the boom system today: the KC-10 and KC-135. Of 
    these, the KC-135 is smaller, less expensive, and more readily available. Of
    particular interest is the KC-135Q and KC-135T. These aircraft have an 
    isolated fuel system, from which the tanker's own engines cannot draw. This 
    will allow dedicated rocket propellant tankers to operate with only minor 
    im pact on the tanker's own systems. To avoid a costly development program,
    and the need to completely re-engineer the transfer system, the propellant 
    carried by the tanker should be non-cryogenic and non-toxic.
    Propellant Selection
    There are only a few non-cryogenic oxidizers available: red fuming nitric 
    acid, nitrogen tetroxide, and hydrogen peroxide are the obvious choices. Of 
    these, only hydrogen peroxide is non-toxic. It has other advantages as well.
    It is very dense (1.432 g/cc in 98% concentration). It has a vapor pressure 
    about one-ninth that of water. It is relatively inexpensive because it is 
    an ordinary industrial chemical rather than a dedicated rocket propellant. 
    Because it is a good coolant, ordinary JP-5 rather than expensive RP-1 can 
    be used as the fuel. Although some special precautions must be taken to pre
    vent it from decomposing in the presence of impurities, it is a stable mole
    cule, and once those precautions have been taken it essentially handles 
   like water.

    Detailed analysis of a hydrogen peroxide/jet fuel engine indicates the 
    following performance figures at a mass mixture ratio of 7.30:1 
    (oxidizer:fuel).  The two columns in Table 1 are for the two versions of the
    engine.  The first version is operable at sea level and permits the aircraft
    to take off, rendezvous with the tanker, and transfer propellant.  The 
    second version is only operable at tanker altitude or above, and is 
    optimized for the climb to space.
    
    Table 1    Hydrogen peroxide/jet fuel engine performance, , 
    , Climb Engine, Takeoff Engine, 
    Chamber pressure, 3000, 3000, psia
    Exit plane pressure, 1.0, 5.7, psia
    Expansion ratio, 240, 70, --
    Ideal Isp (shifting equilibrium), 354, 340, sec
    Losses due to:, , , 
       geometry, 2.4, 2.4, sec
       finite rate chemistry, 1.8, 1.0, sec
       viscous drag, 7.8, 6.6, sec
       energy release efficiency, 6.7, 7.3, sec
    Delivered Isp (in vacuum), 335.3, 323.1, sec
    Thrust, 19930, 19210, lb
    Weight, 280, 310, lb

    The advantages of the aerial propellant transfer concept are threefold. 
    First, the propellants are at a very high density -- 1.32 g/cc of 
    propellant at the 
    mixture ratio given. This leads to a smaller vehicle and the capability of 
    transferring up to 155,000 pounds of hydrogen peroxide from the tanker to 
    the receiver. Second, they are non-cryogenic, so that the modifications to 
    the KC-135Q or KC-135T model tanker will be minimal. Finally, the mixture 
    ratio is unusually high. At a mixture ratio of 7.30 to 1, 88 per cent of the
    benefit of aerial propellant transfer is available if one propellant only is
    transferred. This helps with keeping the operation simple and removes some 
    safety concerns with simultaneous propellant transfer.

    Mission Profile

    The mission profile begins with a takeoff from a conventional runway using 
    the two takeoff rocket engines for thrust. The aircraft is loaded with all 
    the fuel it needs for the climb from the tanker to orbit. It also has fuel 
    and 
    oxidizer aboard sufficient for 15 minutes of atmospheric flight. The total 
    weight of the vehicle at takeoff is about 50,000 pounds, but by the time it 
    achieves tanker rendezvous at 43,000 feet and 0.85 Mach number its weight 
    has dropped to about 38,000 pounds.

    When the aircraft meets the tanker it takes on about 147,000 pounds of hydro
    gen peroxide. It then disconnects from the tanker and climbs to space. As it
    inserts into orbit, its weight has dropped to about 16,500 pounds. After 
    performing its orbital mission, the aircraft reenters and glides to a normal
    landing at a runway.

    Weights

    The weight buildup of the vehicle will determine whether it is possible to 
    enclose the required volume of propellant in an aircraft that weighs little 
    enough to permit that propellant to launch it into space. The table below 
    indicates the assumptions for each of the major weight components and the 
    total weight of the system.

    The basic assumptions made for the vehicle are to apply conventional 
    structural technology by forming the blended wing/body of the aircraft from 
    ordinary aluminum alloy. The thermal protection system technology deemed 
    suitable for this application is carbon/silica carbide for the nose cap, 
    DuraTABI for acreage areas on the lower surface, and a lightweight blanket 
    insulation for the upper surface. The crew cabin accommodations are austere,
    as in the U-2 reconnaissance aircraft.
    
    Table 2  Weight Breakdown (pounds), 
    Structures Group, 6,686   
    Wing, 1,572 
    Vertical tail, 739 
    Fuselage, 2,924 
    Main landing gear, 916 
    Nose landing gear, 243 
    Engine mounts, 292 
    Propulsion Group, 3,091   
    Engines, 2,120 
    Fuel system, 971 
    Equipment Group, 1,181   
    Flight controls, 372 
    Instruments, 142 
    Avionics, 567 
    Furnishings, 100 
    Mission-specific Group, 4,000   
    Reaction controls, 400 
    Life support, 800 
    Thermal protection system, 2,800 
    Total Empty Weight, 14,958   
    Load Group, 33,494   
    Payload, 1,000 
    Crew, 440 
    Propellant, 32,054 
    Takeoff gross weight, 48,452   
    Tanker rendezvous weight, 37,380 
    Oxidizer transfer, 146,870 
    Gross light-off weight, 184,250   

    Design Considerations

    Unlike most spaceplane designs, this vehicle needs to have a particularly 
    high subsonic lift to drag ratio. This is necessary for two reasons. First, 
    the requirement to fly in the atmosphere on the rocket engine impels the 
    designer to minimize thrust required, so that the rocket propellant load at 
    takeoff remains small. Second, the vehicle's gross weight changes by a 
    factor of about 4.5 during propellant transfer. The maneuver will be very 
    difficult for the pilot to fly if the aircraft does not have a good cruise 
    lift-to-drag ratio.

    The aircraft features a highly blended design to maximize volume. The 
    double-delta planform is adopted to provide minimal change of the 
    aerodynamic center over a broad speed range, and also to provide a 
    large strake to hold fuel and 
    oxidizer so that the center of gravity does not move as the propellant is 
    consumed. The overall wing area is 780 square feet. The wing loading is 
    sufficiently low that no lift devices such as flaps or slats should be 
    needed for 
    takeoff or landing, especially with the enormous thrust available from the 
    rocket engine. Low wing loading may also moderate the thermal environment 
    during reentry.

    Flight test

    Unlike most space vehicles, it will be possible to test the aircraft 
    proposed 
    here in a conventional flight test environment. No special range require
    ments beyond what is conventionally available at, for example, Edwards AFB 
    should be required. Because there are aviators aboard the vehicle, no 
    requirement for a destruct package exists.  Aside from storage areas for 
    the new propellant, it should not prove necessary to construct any new 
    facilities for any phase of this program.

    The flight test program could begin in a conventional build-up fashion, 
    starting with taxi and ground tests, first flight, performance, and flying 
    qualities testing. This phase of the program would emphasize handling 
    qualities while connected to the tanker boom, because the oxidizer transfer 
    will quadruple the weight of the aircraft when it takes place. Once the 
    flight control system has been qualified, transfer of steadily increasing 
    amounts of oxidizer would support envelope expansion and flight to increased
    altitudes and airspeeds. Exoatmospheric flight and reentry could be 
    investigated, and the operational envelope of the thermal protection system 
    could be determined. The capability of the system to perform ballistic 
    transfers to anywhere on earth within one hour could be demonstrated. 
    Loading the aircraft with fuel and oxidizer at 7.30:1, up to the maximum 
    takeoff weight, could also permit exoatmospheric flight without propellant 
    transfer. The ballistic ferry range of the aircraft under these conditions 
    is about 3200 nautical miles, allowing for some aerodynamic range extension
    at the end of the trajectory.

    An orbital flight attempt would follow the envelope expansion phase. 
    Investigation of on-orbit flying qualities could proceed at this point, as 
    well as an experimental determination of reentry cross range. One sub-phase 
    of the orbital flight test program of particular interest would be on-orbit 
    propellant transfer. If the aircraft were completely refueled in low earth 
    orbit, it would have enough Dv to visit anywhere in cislunar space, such as 
    geostationary orbits, or to perform multiple plane changes and visit many 
    different points on a single mission. Reentry from increased altitudes and 
    entry speeds could be tested, yielding an assessment of the capability of a 
    high temperature reentry capability in realistic conditions.

    Conclusions

    Using in flight propellant transfer to reduce the Dv needed to fly to space 
    makes it possible for a fighter-sized aircraft to achieve orbit. The 
    enabling technology to do this is non-cryogenic, non-toxic rocket 
    propulsion based on H2O2 and JP-5. Developing this capability permits 
    a variety of militarily significant capabilities to be demonstrated.

Article: 2401
From: [email protected] (Josh Hopkins)
Newsgroups: sci.space.tech
Subject: Re: Black Horse and Usenet
Date: 2 Jul 1994 16:05:40 GMT
Organization: University of Illinois at Urbana
 
I was at the AIAA Joint Propulsion Conference this week, where Robert Zubrin
presented a paper that he and Mr. Burside Clapp co-authored on this subject.
One of the the people in the audience was an Air Force type who apparently
had some experience dealing with hydrogen peroxide and had apparently been
involved in one of the reviews of this technology.  He was adamantly opposed
to the idea of using H202 in high concentrations and was uncertain of the
sanity of anyone who seriously proposed such a thing.
 
I know that H202 has been used on the X-15 and Black Arrow programs (as did 
he).  Could someone who has used this stuff comment on what concentrations 
were used in those programs, and how dangerous this stuff really is.  For
example, how does it compare to LOX, or other industrial chemicals?
-- 
Josh Hopkins                                          [email protected]
 
          He who laughs last probably didn't get the joke.

Article: 2409
From: [email protected] (Pat)
Newsgroups: sci.space.tech
Subject: Re: Black Horse and Usenet
Date: 3 Jul 1994 10:52:26 -0400
Organization: X
 
The British Royal Navy also did extensive trials on H2O2/diesel
propelled submarines. 
 
pat
 
-- 
-----------------------------------------------------------------------------
Nothing is as important as it seems.
 
Article: 2413
From: [email protected] (Henry Spencer)
Newsgroups: sci.space.tech
Subject: Re: Black Horse and Usenet
Date: Sun, 3 Jul 1994 20:37:41 GMT
Organization: U of Toronto Zoology
 
In article <[email protected]> [email protected]
(Josh Hopkins) writes: 

>One of the the people in the audience was an Air Force type...
>...  He was adamantly opposed
>to the idea of using H202 in high concentrations and was uncertain of the
>sanity of anyone who seriously proposed such a thing.
>
>I know that H202 has been used on the X-15 and Black Arrow programs (as did 
>he).  Could someone who has used this stuff comment on what concentrations 
>were used in those programs, and how dangerous this stuff really is.  For
>example, how does it compare to LOX, or other industrial chemicals?
 
If you look in the July 1990 issue of JBIS, you will find a paper by David
Andrews entitled "Advantages of hydrogen peroxide as a rocket oxidant",
which answers this question quite well.  Andrews was chief engineer for
most of the British kerosene/peroxide engine development, including the
engines for Black Arrow.  Samples:
 
	"...it is fair to say that pre-war German reports, on which
	many US studies rely, are irrelevant for the evaluation of
	the oxidant used in British rocket engines.  [Our] HTP was
	virtually a different fluid [because it was free of some
	dangerous impurities]"
 
	"The greatest danger in the use of HTP is likely to arise
	from the fact that it appears to be so safe.  Nine times
	out of ten, if something goes wrong, nothing much happens.
	Danger arises if one becomes blase' in consequence..."
 
The British rocket programs used 85% peroxide, limited primarily by the
metallic-silver catalyst they used, which melted if used to catalyze
higher concentrations.
 
In addition to the X-15, by the way, the USAF's NF-104 rocket-boosted
experimental aircraft used 99% peroxide.  Normal USAF technicians
maintained and fueled the NF-104s for eight years without any serious
problems.
-- 
SMASH!  "Sayy... I *liked* that window."| Henry Spencer @ U of Toronto Zoology
"I enjoyed it too!"  "Hmph!  Some hero!"|  [email protected]  utzoo!henry

Article: 2408
From: [email protected] (Bruce Dunn)
Newsgroups: sci.space.tech
Subject: Re: Black Horse
Date: Sat, 02 Jul 94 17:26:32 -0700 (PDT)
Organization: MIND LINK! - British Columbia, Canada
 
Mitchell Burnside Clapp through George Herbert was kind enough to post a
short description of the Black Horse vehicle.  Here are a few relevant
calculations and conversions from American to International units.
 
> Single stage to orbit flight is technically challenging because the *v
> necessary to achieve orbit (30,500 ft/s, typically)
 
Equivalent to 9296 m/sec; many people use 9300 m/sec as representing the
delta V needed for low earth orbit (good enough for first order calculations).
 
> The probe and drogue system requires the pilot of the receiver aircraft
> to do all the work, and transfers about 250 gallons per minute. The boom
> system requires some cooperation between the boom operator and the
> receiver aircraft pilot, and can transfer 1200 gallons per minute.  [and
> later in the article] ... the capability of transferring up to 155,000
> pounds of hydrogen peroxide from the tanker to the receiver.
 
Total peroxide to be transferred is 70,454 kg.  A probe and drogue system
transfers 945 liters = 1352 kg peroxide per minute, giving transfer times
of up to 52 minutes.  The boom system transfers 4542 liters = 6495 kg per
minute for a transfer time of about 11 minutes.
 
> Table 1    Hydrogen peroxide/jet fuel engine performance
>
> Ideal Isp (shifting equilibrium), 354, 340, sec
>
> Losses due to:, , ,
>        geometry, 2.4, 2.4, sec
>        finite rate chemistry, 1.8, 1.0, sec
>        viscous drag, 7.8, 6.6, sec
>        energy release efficiency, 6.7, 7.3, sec
>
>
> Delivered Isp (in vacuum), 335.3, 323.1, sec
 
        Its nice to see calculations of delivered Isp.  The calculations
give real Isp at about 95 % of theortical - this makes me happy, as I have
been assuming 95% for the purposes of estimating delivered Isp for pressure
fed peroxide/hydrocarbon engines for expendable pressure fed vehicles.
 
        There is no term for peroxide used for turbopump gas generators, so
the engines presumably must be a closed cycle system (this is also implied
by the very high chamber pressure).  No such engines currently exist but
there is a good potential for a rather straight forward cycle somewhat
resembling staged combusion, in which the peroxide:
 
1) cools the nozzle and chamber
2) is decomposed via a catalyst into superheated steam and oxygen
3) powers the turbopump
4) is injected into the engine, where fuel is added
 
        The pumps don't have to handle cryogens (no cooldown needed), and
the propellants are dense which lessens the power needed.  Nevertheless, I
expect that engine development will be the pacing item in Black Horse
development (as was true for some of the X-planes).
--
Bruce Dunn    Vancouver, Canada   [email protected]

Article: 2424
From: [email protected] (Dave Stephenson)
Newsgroups: sci.space.tech
Subject: Re: Black Horse and Usenet
Date: Mon, 4 Jul 1994 10:40:20 -0400
Organization: Geodetic Survey of Canada
 
Pat ([email protected]) wrote:
 
: The british Royal navy also did extensive trials on H2O2/diesel
: propelled submarines.
 
: pat
 
The British took over a U-boat at the end of the second world and
renamed it the Meteorite. This used the Walther H2O2 and diesel fuel
system. (Submerged it could out run a frigate!) The U.S. also
experimented with the system for midgit boats in the late fourties.
Eventually the U.S. navy and the Royal navy agreed on an almost unique
research partnership. The U.S. would develop nuclear propulsion, and
the Brits H2O2. The RN built two subs called the Excaliber and the
Explorer and they rapidly gained the nick name the "Exploders". The
control systems were not that good, and the boats tended to fart great
balls of fire. Not good for the silent service. Even so the RN learnt
how to handle HTP in quantity safely. Eventually it was agreed that
H2O2 was not suitable for submarine propulsion and very grudgingly the
U.S. handed over a first generation nuclear reactor for HMS Dreadnought. 
 
H2O2 is a bulk industrial chemical, costs about dollar a Kg at 70%
concentration ( the highest shipping concentration) is available in
railcar lots. Its main and increasing use is as a bleaching agent and
is the leading 'green' replacement for chlorine products in such
industries as wood pulp and paper and domestic water supplies. 
 
Note: decomposing 85% H2O2 releases about half the heat released from
BURNING the same mass of medium hydrocarbon fuel. Volume for volume it
is about 3/4. And then you can still burn fuel in the oxygen released!
Decomposing 85% H2O2 produces 600 C steam and oxygen at about 20 atm.
(about the same steam pressure as found in an old time steam locomotive) 
--
Dave Stephenson                   
Geological Survey of Canada       *Too much bad arithmetic is not a *
Ottawa, Ontario, Canada           *substitute for not enough good   *
Internet: [email protected]    *         mathematics             *          

    This is interesting, another space plane, first I hear about it.
    
    A clear extension of today's military plane designs ...
    Wonder if it will ever get off the ground, I mean what do you
    do with a 1000 lbs (450 Kg) payload. (-; shoot it out ;-)
    
    Gil

Sad to say that it's plenty of payload for a nuke...

    Zubrin & Clapp have a 20-page fact article on Black Horse and the Black
    Colt & Black Yearling proof-of-concept vehicles in the June '95 issue
    of Analog Science Fiction & Fact magazine (ISSN 1059-2113).  It's a
    good read and gives a convincing argument that aerial propellant
    transfer has great advantages for a SSTO spaceplane - unfortunately
    nobody seems to have coughed up any funding for Black Horse yet, or
    even for Black Colt / Black Yearling.