Here is a tidbit that may help clarify some of the issues. Pg's 43 and
44 of
the document are about the most relevant. Take note of the geared Lycoming
bush pilot failures and the remedy.

Dale Davies

Very interesting Dale. I think Merlin's had a TBO of less than 1000
hours but few in combat ever made it that far.

Here is the gear set used in the S-51 scale P-51 big block
Chevy powered version. We called them rock crusher gears.
Reputed to be designed by a RR engineer involved in the original.
The box was well over 100 pounds and some final version used a heavy
flywheel in an attempt to extend the life.

I think every S-51 ever made crashed for one reasons or another.

Paul Lamar
--
   I met the gear box designer at Oshkosh.  He was a friend of Jim Stewart
and was from Allison not R-R.
   The steel used in the gears was a lower alloy than I would have
expected as I recall.


Murry I Rozansky

I stand corrected. Thanks Murry.

Paul Lamar