[AR] Re: Dempster Turb-O-Prop
- From: Norman Yarvin <yarvin@xxxxxxxxxxxx>
- To: arocket@xxxxxxxxxxxxx
- Date: Thu, 11 Feb 2021 17:20:35 -0500
On Thu, Feb 11, 2021 at 12:45:42PM -0500, Henry Spencer wrote:
On Thu, 11 Feb 2021, Dr Edward Jones wrote:
Bet none here have heard of this odd-ball use of rocket power for
propulsion...
How much do you want to bet? :-) Google 'rocket on rotor' for (among
other things) videos of helicopter rotors powered by tip rockets.
Speaking of which, it's been kind of a mystery (to me, at least) what
went wrong with Roton. The company started out with just such a
scheme (tip rotors with the rotor acting as a pump), switched to a
slightly more conventional arrangement (still with the engine rotating
and that doing the pumping but no rotors pushing air), then ran out of
money, whereupon the people doing the engine development formed Xcor
and went to a completely conventional arrangement. Since even that
latter company is now defunct, maybe people can finally spill the
beans as to what drove those moves on a technical level. Having the
rotor acting as a pump seemed like an easy alternative to turbopumps,
and pushing air is an excellent way to augment thrust; but somehow the
same team that decided that these were good ideas later decided they
weren't -- or perhaps just that getting them done was way beyond their
development budget.
(Thinking about it, I can imagine some very thorny vibration issues
with a rocket out on the end of a rotor.)
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