From: Michelle Jones (spike66@ibm.net)
Date: Thu Aug 13 1998 - 23:58:49 MDT
Michael M. Butler wrote:
> >... To get into orbit cheaply, you need to build your rockets Big and Dumb...
yup. looks like there are three showstoppers for well funded amateur groups.1.
regardless of how big and how dumb a liquid rocket is, one still mustpump a high
volume of cryogenic liquids to combustion chamber pressure .
2. generally rockets have a high l/d problem: they are tall and skinny, in order
to
reduce atmospheric drag. so, there is a great deal of science in the structural
dynamics of the system. this was a major problem in the early days of
rocketry.
3. guidance and control: this is a very complicated problem generally, requires
a sophisticated feedback mechanism with thrust vector control by means of a
steerable nozzle for instance.
there are a lot of different concepts all going under the name roton, some
workable,
others not. i have only recently come to appreciate this. the beauty of the
simplest
roton system is that it solves all three of the above, sort of. centrifugal force
pumps
the cryogens. you need not have high l/d, since you can give away some
performance.
the inherent stability spinning about an axis with high moment of inertia obviates
a flight computer. there are still some difficult problems, such as how to turn
the
vehicle, but i have some ideas. a roton could be conceive which has very few
moving parts.
like apple computer, the roton concept is not really being sold right, in my
opinion.
when the rotoners say that it might raise payload at 1/5 the cost of conventional
rockets, they should perhaps make it clear that what is meant is a system that
raises payload at 1/10 the performance at 1/50 the price... either way, the roton
is within the reach of sophisticated amateurs and underfunded entrepreneurs.
spike
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