bildan wrote:
On Feb 14, 6:38 am, jan olieslagers
wrote:
My friend absolotely wants it in the plane as it is in the car, i.e.
with the clutch side rearward (the plane is a traditional "puller"), and
wants to take power from the clutch side. His idea is to have a belt
reduction "behind" the engine, then a transmission axle above the engine
to drive the prop.

I think the key is that the shaft has to be thin and flexible to get
its resonance well below that of any other part of the drive train.
Going the other way to make a very stiff shaft raises its natural
resonance frequency so it's likely to match some other component
resulting in destructive resonance.

You should model that sometime...

Charles