Paul wrote:

No doubt about it. The end thrust from helicals has been a pain in the
a** for us. If we had an easy to adapt, low cost and strong enough spur gear
planetary we would be in rotary engine PSRU heaven.
Paul Lamar

Paul, how about cutting up a high performance sportsbike engine and section out
the transmission area? might be a bit heavy but would not be too $$$.

Has anyone left the stock Mazda tranny in, and could you swing a larger slower
moving prop and then "shift' during climb out?

No shift but stock transmission have been used. Car transmission output
shafts are too small for prop gyro bending loads. The Mazda manual transmission has
an output shaft only 0.8 inches in diameter. It is very dangerous to do that.
Tracy's new shaft is 1.77 inches in diameter. The Ross is 1-7/8 inches 
in diameter. The Power Sport and Marcotte is over three inches in diameter. 

The bending stress in a shaft is inversely proportional to the third or 
fourth power of the diameter. Most AC engines have prop shafts well over 
two inches. That is why the akro guys are going nuts buying Power Sport 
engines and Gear Boxes :-) PL

Flew on one of the newer large twin turbo props from, crap brain fart, cant
remember now (flew US Scare). But it seats about 20 is made in Germany, P&WA
engines, and does a 300+ kt cruse. But even at cruse the props seem to be
turning VERY slowly as compared to a normal small plane. (a LOT less than 2500
RPM)

Just a bit of curiosity between finals this week,
Blake
Cozy MK IV Plans #8

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