Would it not be possible to replace all of the ford gear set in Tracy's PSRU
on a time bassis? For example every 1,500 hours, or ten years for the average
flyer, or even 7 years and 1,000 hours?

This would remove the tooth fatigue avenue for failure. Also tooth wear can
be checked by rocking the prop tip back and forth. A good thing to add to each
preflight
check.

The failed Ross looked as though a lubrication failure may have been
involved. Perhaps the engine thrust bearings should be checked.

Lynn E. Hanover

This is the first gear failure I have seen other than those due to Ross
gear box machining errors, Ross overall gear box design errors or lube errors
as you mentioned. I never expected the four pinion to stand up to the 50% 
greater HP of the 3 rotor let alone a TURBO 3 rotor. We had started
to build some six pinion planet carriers before Ford starting manufacturing
them. They were also available from a company called Art Carr and were used
in racing. Brice Dunay, Chuck Harbert and Tom Parkes bought their gear boxes
for use with their 3 rotors long before the six pinion was available.
 
 
Paul Lamar
 
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