Paul Carey wrote:

Hi Paul

I have been researching the Wright PT for installation on our blown
20B, and had a question for you to ponder.

The wright engine uses a complex gear/fluid drive scenario. What do
you think of us using just a belt drive?
The ratio would be roughly 2:1, with the engine @ 8000rpm, and the
PT @ 16,000rpm. I was thinking of a wider (3inch) grooved belt, so
some slip during rapid accereration would prevent damage. I have
read that was why Wright used the fluid drive - to settle the drive
train down a little. Looks to me like the PT has some sort of clutch
in the can. I am off to the airport tomorrow to question our
resident Neptune operator - he has spare PT's lying around.

Regards

PC


                 Aviation Consultants
           226 Railway Parade
           BAYSWATER WA 6053
                         tel: (08) 9371 5205
com.au                   fax: (08) 9371 9644
.com.au               mobile:  0418 959 892

Thanks for the great pictures Paul. I am glad to see
you are pursuing this potential rewarding configuration.

The problem with a belt in this application is HP.
You are looking at 20% of the power you have now which
will be well over 1000 HP. That means you are unlikely
to find a belt that will transmit 200 HP or more.
You also need the belt between the final gear reduction
and the e-shaft as you don't want torque pulses from the main
engine feeding back into the turbine reduction gears
to destroy them.

I think you are stuck with a fluid coupling or some other
torque isolator such as the rubber device Don Dunbar is using. 
The torsional dynamics are a bear otherwise.

As Vance quotes some Englishman  "An ounce of rubber is worth 
a pound of engineering." :)

Paul Lamar
 
The AirCraft Rotary Engine NewsLetter.  Powered by Linux.
ACRE NL web site. http://home.earthlink.net/~rotaryeng/            
Copyright 1998-2003 All world wide rights reserved.