The issue of low idle speed and smooth, responsiveness to throttle  settings
is also related to issues regarding the reduction gear.  The low engine idle
was possible with absolutely no gear rattle when we developed the later
planetary reduction gear units with pendulous dampers.  Following that
development, the challenge became to design a reduction gear that eliminated
completely the need for ANY dampers or isolators of any kind, so we could
further reduce parts count, improve safety and lower costs for consumers.
This approach was possible only becasue of the Mazda's exceptionally short
and stiff eccentric shaft.


 These developments led to the design, testing and refinement of the straight
cut, torsionally stiff internal spur gear reduction unit which would work at
any engine rpm within the operating range with no dampers, absorbers or
isolators.  When you were at the house you saw our preproduction unit which

Steve Weinzeral further refined in his design that Ray Richardson machined
at Ratech Machine under a "Powersport Aviation" name.  Steve and Ray
incorporated a full CNC-produced power section adaptor.  Ours was cast.
Steve retained a rear thrust ball bearing as we did in the second prototype
unit.  It was far superior to the original prototype thrust arrangement.  In
the front prop shaft between the internal spur gear and the prop flange we
used a plain bearing similar to the Lycoming front crankshaft bearing, but
Steve W.  opted for an additional super-precision ball bearing at the front
of the prop shaft.  He retained our use of a pinon support bearing.  Our
first prototype unit did not have a pinion support bearing and it quickly
became apparent we needed to incorporate one in our second prototype.  It
significantly improved the design.

Overall, we felt this approach to a reduction gear was a successful
application of a simplified "less is more" design, and a major advance and
logical culmination of our years of development.  In this form it was an
extension of the simplicity of the rotary engine design and our driving
mantra that if it is not there it cannot wear, require maintenance or fail.
Based on our experience, the most difficult design challenge is to simplify
while improving strength and efficiency.



 As to the throttle placement, plans were to later transition the throttle
 plates just immediately outboard and attach the throttle body to the
 periperal port inserts to reduce costs further for customers at what we
 hoped would be negligible degredation in idle and throttle response.

 Steve Beckham



Steve,

Thanks again for explaining all of this background.

I am interested in knowing how wear in the gear seat manifested
itself.Was there increased lash?  Could that be adjusted out?  Did
increasing lash cause any change in operation?

Are you familiar with the gear reduction on the Continental GO300?  I
believe that's an external spur gear..


Regards,

Matt-



Steve,
Do you have a cut away sketch of the spur gearbox? milo