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
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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

Mark W wrote:

I think the the real problem is one of airflow. The R-3350 TC's turbo
cyclones were rated at 3250HP, that is ~10x the HP of a 20B. There airflow
was divided across three turbines on the R-3350, but that still means each
turbine is sized for around three and a half times the airflow a 20B will
reasonably deliver.

I came across this site while looking for the rating of the R-3350. Nice
drawings.
http://www.enginehistory.org/vicenzi.htm

Regards,
Mark W
www.wankel.org

Mark you are missing the roots blower :) Paul's 3 rotor engine should generate close
to 1200 HP or more. Perfect for a R3350 TC turbine.

Paul Lamar
 
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