"George" wrote in message
m...
Richard Lamb wrote:
ADK wrote:

IF you had to design a PSRU, to drive a pusher propellor via shaft, what
would your experience dictate? Thinking along the lines of a gearbelt,
chain or gear. Please, I would appreciate the collective experience
available on this group. I have decided on the aircraft, but want to
make it the most reliable and safest it can be.

"ADK" wrote in message
news:X6TXf.28774$%H.11944@clgrps13...

This is probably going to open old wounds. What I would like is
experienced input on the advantages, for economic, efficiency and
longevity etc. of different types of redrives.

I am leaning towards a cog-belt reducer in a 6 cylinder, liquid cooled,
configuration driving a long drive shaft to the prop.




The collective experience is zilch = nada = squat = undefined.

THAT is what everybody had been trying to tell you.

Wait a second. Look around the airport.

How many shaft driven propellers do you see?

Have you ever seen?

If you are heart set on doing it, I sincerely wish you luck.

But I can't offer any further advice - 'cuz they ain't none...



Richard


Richard,

Didn't the military do this once?? Seems there was the P-39 Aircobra,
shaft driven from a rear mounted engine?? Are the gray cells working that
far back??

Not that it would be applicable to an experimental, but at least It was
once done?

George

Yep. And Molt Taylor did it on several different airplanes and with several
different engines. There have been several pushers with engines mounted
near the CG and the props back on the tail with long drive shafts. Several
of them worked very well. There is a gain in efficiency when you do that.
Unfortunately the increased weight of the drive train and the additional
cost and complexity of the requisite drive train generally overcame any
efficiency gain and none of them has ever gone into "production."

The P-39 was a special case. It had an aft mounted engine and a big
driveshaft that passed between the pilots legs! It scared a lot of pilots
thinking about what they would lose if the drive shaft pickled on them.
They also used the drive shaft for a gun barrel for a large bore cannon so
that it could fire straight ahead through the spinner and be easy for the
pilot to aim. Just point the airplane at your target and cut loose. The
additional weight of the complex drive train raised hob with the performance
and our pilots didn't like them at all. The Russian pilots loved them.
They could aim the whole airplane fairly well and when you ran out of cannon
shells they would just ram the enemy fighter. That brought down both of
them, but the russians didn't mind. They were fighting in their own
backyard and the German's were not.

Highflyer
Highflight Aviation Services
Pinckneyville Airport ( PJY )