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Discussion: Rocketcars and Historical Examples

Posted by: The Legionnaire - Wed May 12, 2004 12:57 am
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Discussion: Rocketcars and Historical Examples 
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Space Walker
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Post Discussion: Rocketcars and Historical Examples   Posted on: Wed May 12, 2004 12:57 am
Hi everyone,

In the past few weeks there has been a lot of discussion about rocket cars versus rocket spacecraft, and the relative virtues of each. The discussion has become quite heated, to say the least. Although the moderators do not condone such behavior, we do favor the freedom of speech and the dissemination of ideas, so we will allow discussion of rocketcars to continue. Please make all new rocket-car related postings under this thread, as well as under the other two threads "Discussion: Rocketcars and the X PRIZE CUP," and "Discussion: Rocketcars and X PRIZE."

Thank you.


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Space Walker
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Post    Posted on: Wed May 12, 2004 1:04 am
To get this forum started, I've pasted some of the comments from other threads that are now gone.

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The single passenger X-3 "Volksrocket" of which Bob Truax built a prototype about 20 years ago had a dry (empty weight) of 900-1,000 lbs (about the same as a rocket dragster) and a thrust of 4,000 lbs (less than some rocket dragsters). This suggests that a variety of ultralight vehicles (including aircraft) might be possible capable of putting a person into space. Might an X-Prize winner, and crossing the psychological barrier of private spaceflight, have happened sooner if only a single occupant had been the requirement?


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A very good point, Franklin, and I believe you are correct--private suborbital flight WOULD have happened sooner.

But, what I think is the X-Prize's objective here involves creating an industry, not just a single achievement. If rockets (or whatever) are developed that can economically carry passengers into space, albeit suborbital at first, then we have an industry and not just the occasional solitary daredevil.

At least, this is my take on it.

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And who wants to go alone?

Yeah the whole idea is to have somewhere you can sit when you are just paying a fare.

Two fare's are good. Something that can carry six fares would be better.

A single seater could never generate revenue.

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I don't think so. There's been a lot of different types of pressure until recently that prevented any sort of private space ship work. The biggest in my opinion being the 'giggle factor' whenever anybody was trying to seriously looki into it. Although I sometimes think if someone like John Carmack had appeared 20 or so years ago things may very well have been different. He and his group definitely seem to do things differently than the typical group of aerospace engineers. They're certainly spending a good deal less than most have in the past 30 years. They should be able to match or better the DC-X this year for far less than the 60 mil spent on the DC-X and that was considered a bargain. Burt Rutan has been trying damn near every and any angle to get a private space industry going since at least the 70's I believe with no luck. One things for sure he certain shows that persistance can really pay off.

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The idea of the X-Prize happening sooner falls under the concept,
"could have would have, should have."

You can say the same thing about liquid-fueled rockets in general:
turbopumps, liquid-oxygen in commercial quantities, aluminum, gyroscopes,
high-grade steel, kerosene were all available in the 1890's...
unfortunately we had to wait unto 1926 before Mr. Goddard launched
the first primitive LFR.

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So yeah, you could say that, except by 1965 the Turbonique company in Orlando was offering for sale by mail order monopropellant rocket motors and hot gas generator powered turbines, except by 1966 Reaction Dynamics was running the 2,500 lbs thrust X-1 hydrogen peroxide monopropellant rocket dragster, except by 1970 Reaction Dynamics had set the World Land Speed Record with the 16,500 lbs thrust throttleable bipropellant Blue Flame rocket car, and except by 1973 Craig Breedlove was running his nitrogen tetroxide/UDMH bipropellant rocket dragster (with a motor based on TRW's lunar module descent engine).


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I would think that mach 2 on the ground would be far more difficult than mach two in the air. It's been what, seven years since the sound barrier was broken on the ground and despite it being a neck and neck race then it hasn't been done by anybody else since. For all anyone knows Trust SSC was simply lucky that the shock wave bouncing off the ground didn't tear their vehicle apart. It's not like they were hanging out at mach 1+ for very long. That shock wave reflection has got to put a real damper on any sort of higher velocities. I think John Carmack and Armadillo along with the other real teams will be putting people into orbit and safely returning them long before someone hits mach 2 on the ground.

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You just can't get past outward appearances and keep fixating on the word "car" instead of the rocket motor IN the car (despite repeatedly having pointed out to you the thrust, whether the motor was throttleable, and [if the motor was bipropellant] the propellants used).

The point was over 30 years ago private individuals were already designing and building at a level of rocket technology comparable in thrust and/or sophistication to an X-Prize vehicle.

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It is really really really easy to build a rocket engine.

It is really really hard to get someone to pay to ride IN it.

My only thing against cars it that they are limited in what they can do.
Nobody cars about the engines in them. Half the X Prize teams have already got working engines. Plus I was unaware that the Rocket cars were powered by liquid hydrogen. That one got past me.

What would be really cool is if Cragi Breedlove or whoever could show us how to get a thousand people to ride in a rocket car.

That is something that would be useful to the X Prize.

What the point of building an X Prize Rocket just to fly once. Speed and distance records are all held by the Apollo crews.

If the Xprize Class was only single seater then it would be for EGOmaniacs like the Rocket car people who spent all their time in one up-manship.

Instead the X Prize is about Entreprenurship and philanthropy. Its about making rockets that Anybody and Everybody can ride. It would have been set to six passengers but thts even harder.

Three is the minimum number of passengers for construction to be about more than individual egos.
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I think that John Carmack has said that they may focus on a single person rocket after the X-Prise is finished. I can't remember where I was reading it and it may have been unrelated but I saw something on how a single person RLV with little cargo capacity could be extremely valuable in regards to a satellite repair, maintenance and such business.

Now as for the whole 'race to space' business, with all the talk about a new space race featuring China and the U.S. and the X-Prise nearing it's deadline, I think it's going to be interesting seeing how many additional players are really going to be in the next space race.


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Space Walker
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Post    Posted on: Wed May 12, 2004 1:08 am
Here's some more posts.

http://www.wpafb.af.mil/museum/modern_flight/mf34.htm

For one thing, it demonstrated you don't need computers for VTOL.

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http://www.fiddlersgreen.net/AC/aircraf ... o/info.htm

With rocket motors in the nose replacing the props, the Convair XFY-1 design would also have made an intriguing basis for an X-Prize contender.

However, I'd consider putting the pilot in a headfirst position so that during a VTOL landing he's on his feet instead of looking over his shoulder.


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