Apparently there are some things we need to clear up about C6 based PSRU's.
First is the failure of the Mazda thrust bearing does not happen all at once.
The end play can be checked by grabbing  the front pulley and moving the e-shaft 
back and fourth. It sure has had plenty of publicity on here. Unfortunately 
Power Sport has focused on a non-existent torsional resonance problem which
does not exist. Not the helical gear thrust bearing issue.

There is a prop thrust needle bearing on the Ross that is 45 MM ID but 
it has never given any problems. That is not the thrust or thrust bearing 
we are talking about. It is the thrust from the helical gear trying to unscrew 
itself from the planetary. This is the thrust that eventually destroys the 13B 
30 mm ID needle thrust bearing by way of end thrust on the e-shaft.
This bearing is somewhat less than 45 mm ID and of much lower capacity. 

This is a drawing I made of Tracy's redrive.

Tracy has added a higher capacity roller thrust bearing to his gear box and 
it is right behind the gear as shown in this drawing.
The large 45 mm ball bearing at the front of the re-drive takes all prop 
thrust and half the prop gyro loads. 

The word "OPTIONAL" on the drawing refers to some suggestions of mine to 
Tracy on how to reduce the weight.

In the Ross case there is a large needle bearing in front of the ring 
gear bulkhead to take prop thrust. This bearing has not given problems. 
However there is no SUN GEAR thrust bearing in the stock Ross gear box. 
IMHO it is not that hard to add one.

Paul Lamar
 
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