Al Gietzen wrote:

Paul wrote:

This is a real good article on the problems of PSRU design.
I got this indirectly from Jim West
I will also upload his complete message.

http://www.prime-mover.org/Engines/Torsional/sport_av92/sport_av92.html

This is a good and interesting article by Bill Husa; but should not be
referenced without also referring to a followup by Keith Spreuer;
http://www.prime-mover.org/Engines/Torsional/contact2/contact2.html
which shows that Bill Husa seriously overestimates the gyroscopic forces.

Al Gietzen

I read the next one after I uploaded that message. I am not sure
I agree Al.

Maybe the truth lies somewhere between the two as they both are
based on guesses of the pitch rate of change. I have been meaning
to look up some pitch accelerations numbers from turbulence data.
Any idea where to look? The one thing that keeps coming back to
me is the size of most aircraft engine shafts and the problems
that VW AC engines have had with broken cranks. Wood props are
nothing new with aircraft engines. 

BTW I mentioned this a while back but an air boat
operator in South Florida told me he could break the crank in
his direct drive 500 ci Cadilac v8 air boat engine by going over 
bumps at high  speed with his wood prop. 

I think the jury is still out.

Paul Lamar
 
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