Essentially the planet carrier becomes part of the prop shaft doing
     two jobs. There are only two ball bearings in the entire PSRU. The
     forward ball bearing takes the prop thrust.

     It is only 7 inches long which is half the length of Tracy's redrive.
     Don't get too excited about the weight as that Allison planet is
     heavy being designed for over the road tractor trailer 450 HP diesels
     towing 50,000 pounds..

     The Allison planet and ring gear, sun gear, input shaft is 26.7
     pounds alone.

     The $30,000 Bell 47 weighs 35 pounds with out the Sonja :-) Tracy's
     is 45 pounds. But could be lightened if a 2 inch hollow prop shaft is
     used.

     This design  picks up 7 inches behind the engine for all aluminum
     rotary engines only. Other wise you would have a forward CG problem.
     I may not have to move the firewall back on the Glasair.

     This is also much cheaper to make as no long PSRU housing is needed.

     I got some of these ideas from the Bell 47.

     Paul Lamar


   That’s an awesome idea.  I just hope the planet cage and gears are up to
   resisting the gyroscopic forces from the prop.  If you extended the
   length of
   the prop shaft another couple inches, you could add another set of bearings
   to help with that.  But in either event, those front bearings have to be
   housed in something which can be opened for access.  Probably the front
   part of this housing would need to be detachable.

   Gene Kahn

   It is all in the steel planet cage. The gears are not involved.
   The steel planet cage is bolted solidly to front and back prop
   shafts via their flanges..

   Actually it is better than the kludged up Bell 47 TX we have now.
   Some of the bending load is taken by a small double row bearing.

   Here is a 3D. Take a close look at this :-) A Sonja design.

   We have no intention of doing aerobatics or stalling the air-plane.

   Paul Lamar

   Here is the cutaway for the Aillison.

    IT IS INDESCRIBABLE SIMPLE!!!!!

   On the four rotor I am not going to use a flexible coupling
   as the 4 rotor torque pulses are much smoother.

   Less weight.


   Paul Lamar

For this to work the center shaft will be turning faster than the inboard section- are you planning a plain bearing there with an oil feed?
Will there be an inboard seal with a backplate to keep the oil in and a seal around the shaft?
What are the ends (brown) made of. Looks much like Tracys axle shafts.

Kevin Alderman

The sun gear shaft is piloted in the prop shaft ahead of the
planetary with a small diameter drawn cub needle bearing.
There is little or no load on that bearing because planetary's are
self aligning. Max RPM for a one inch is 11,000 RPM.

It is also piloted in the e-shaft. Of course there is no relative
rotation back there. Actually the best place to take the
helical gear thrust is at the head of the engine. Back to back
needle thrust bearings will do the job. The stock 13B only has
one. Tracy failed one as did Perry Mick.

Good idea. I might be able to use a couple of forged axle  shafts for those parts.
Cut way down of course. That would save some machining.  I intent to drill
the front one out to save weight. The drill size would be determined by
the OD of the drawn cup needle pilot bearing. Roughly 1 inch.

The back seal in the gear box adapter plate will be carbon Teflon 1.5 inch diameter.
Tracy's is one inch in diameter. We may be able to use the Allison 1.43" dia. input
shaft as is. It is drilled end to end about .4 inch diameter. Total length is 10 inches.


Paul Lamar


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