If you ever wanted to know what a Bell 47 Helicopter gear box looks
 like take a look at this.


 http://cgi.ebay.com/ebaymotors/BELL-47-M-R-transmission-helicopter-part-/320585434705

 The price is a bit steep so this is probably as close as I will ever get to
 one.

 Erik

 Here are some pictures I took when adapted to a rotary.

 Paul Lamar

 Paul,

I didn't see a torque damper in the pictures?  Does it even have one?  Do
you have any pictures?

The prop attachment seems a little flimsy.  Is this a tapered shaft or what?

Mark

No torque damper. Dave Garber had some Bell engineers check it
for 6000 RPM input and they said it was good to 1000 HP.

The prop shaft is probably the weak link as I don't think
any calculations were made on the gyro reactions due to A/C stall
or spin situations. One needs widely separated ball or roller
bearings to deal with gyro bending moments of up to 600 foot pounds.

I borrowed the airplane from Dave and ran it up at Sun n Fun
in 2005. 45 inches of HG was Dave Garbers imposed limit.
Estimated power was 350 HP each of two engines at 6500 RPM.
It could blow down trees :) Well over 400 HP has been had
from turbo 13B's running on gasoline and higher RPM's.

Paul Lamar