Paul,

Thanks for the info. I believe I have enough to design a chain drive to
fit the rotary now. Tentatively I plan a 7.5" offset and a 2.76 ratio.
I'm planning to use a stock Renesis as I have the room under the cowl to
fit the whole motor as long as the crank center is lower than the prop
center.

Soon as I finish my 3d of the fuselage I will start drawing the drive.
Anyone know how to transfer an Acad wireframe 3d into SolidWorks?

I'm sure I'll have some more questions at that time.

Thanks again
Ken

I am curious Ken. What kind of airplane is this going in?

Your target weight for the PSRU should be less than 35 pounds which
is what the Ross is. Let me know what you come up with.

Paul Lamar

No, I will be a bit heavier. Closer to 40-45 lbs. It's a trade off I can
live with. The Ross drive is built too light for my intended prop moment
of inertia. I'm looking for 180 hp to swing an 87" prop. The bearing
load generated by the chain is 2005 lbs. Combine that with the RPM and I
need fairly significant bearings. Chain alone is 7.05 lbs. I'll need to
do a bearing analysis before I know their wt.

I looked hard at two other engines, but to get the power I wanted
required boost. The rotary wins out in simplicity and weight. The other
engines would have been 200 hp and around 410 lbs all up.

Fieseler Storch.

Ken

There is a chain drive available on the field here at SZP. Fits a
small block Chev V8. Might be adapted. I'll ask him what it weighs.
He is asking $10,000 for the PSRU.  The ratio is 2.25:1 which is not really enough for a rotary. You need more like 2.85:1 or even 3:1.
www.legendaryaircraft.com

Paul Lamar


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