"Ray Richardson Jr." wrote:

Hello Paul and fellow rotary aviators.

Thought that you might like an update on our progress and testing.

Sales of engines and reduction drives continue, and we currently have
85 hrs. of flight time on our RV-6A. The engine has been subjected to 128
hours of extreme duty, starting life as a dynamometer mule, then moving to
the RV for our enjoyment/ abuse!! It remains extremely strong with an
exceptionally broad power curve providing 190 mph indicated @ 2300rpm/prop!
We could not be happier with the reduction drive.  It runs very smooth, and
maintains a very tight gear mesh. The ring gear has been removed several
times for inspection, and shows no signs of wear.  A more easily adjustable
mount for the electric MT prop governor is in the works that will eliminate
the need to drill and tap the "bell" housing.

We have been receiving inquiries about the use of our drive with a 3 Rotor,
and welcome the interest.  Everett Hatch flew with many "planetary"
reductions, some with pendulous dampers to control resonance, with the
earlier 200hp output, and failed every one in less than 100 hours. Adding
more "planets" does not solve the resonance problems associated with a
planetary reduction used on a rotary engine.

Our Internal Spur Gear reduction drive is designed to handle 300hp
continuous, for 2000 hours. The strength of the gear tooth is good for
450hp. We have not yet
performed the vibration analysis on our drive when couple to a 20B, but
would soon if people are at that stage in their projects.

We sincerely hope that all rotary aviators have a safe and successful
experience, and as we add "more power" that we can deliver it to the prop
reliably.

Fly safe

Ray Richardson Jr.
www.powersportaviation.com

Thanks Ray. Good report.

With all due respect Ray I think Everett was wrong about planetary
reductions.  Planetary reductions of course have been used with aircraft 
engines since the 20's or 30's. Even the huge P&W R4360 3000 HP engine has a 
planetary reduction. See the picture below.

Here is a little background on what is going on in the planetary psru world.
The gears in the Ross never gave any problems in dozens of rotary
powered airplanes and gyros. What did happen is the end thrust from the helical gears
destroyed the Mazda thrust bearing in about 600 hours. Tracy has addressed that in
his design with a separate thrust bearing. Others have modified the Ross.
The Ross spring clutch disk works well to isolate the Mazda torque pulses 
from the gears but sometimes causes a resonance down around 1500 engine RPM 
in some installation but by no means all. Tracy has addressed that too in 
his design with a new rubber based damper. That seems to be working well. 
I have flown in Tracy plane with his redrive and Chuck Dunlaps plane with
the Ross with no sign of this  resonant problem.

The other major thing in the works is a six pinion planetary carrier that will
be a retrofit  in both the Ross and Tracy psru. This should up the torque capacity
to about 150% of what it is now. The bottom line is none of these boxes
are giving any problems now with the thrust bearing fix.  Perhaps people are
not getting enough power to have an effect on the gear box so far but that 
reality is sometime in the future. 

Paul Lamar
 
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