Thomas Parkes wrote:

Paul:

In reply to your query, Yes I'm very much still here, but very, very busy.
On the one hand I'm working 40 hrs per week teaching CFI academics.  On the
other I'm diagnosing problems with my Ross redrive, which at 78 hours has
developed a fatal illness.

I mentioned last month that I'd detected metal particles in my oil.  Since
then I've traced the problem to a broken Sun-gear tooth, which tore up the
Planetary pinion gears.  Only one tooth was slightly damaged in the Ring
gear, but there were several gouges inside the ring-gear bulkhead.  See
attached photos.

Notice that the Sun-gear tooth failure began at the oil lubrication hole.
Notice also the apparent galling of the sun gear teeth.  I don't know if the
tooth failure caused some of this galling, or if it occurred previous to the
tooth failure.

I had hoped to repair the redrive and replace the 4-pinion planetary with a
six-pinion unit, but with the galling of sun-gear teeth I am wondering if
the effort would be worthwhile.  A couple local mechanical engineering
retirees tell me that the tooth failure appears to be a high-cycle fatigue
failure, although it may have been damaged during the manufacturing or
assembly process.

My next step is to dissassemble the forward housing to inspect for further
damage and see if the prop shaft and bearings are usable.  More on that
later.

Tom Parkes

Looks like you will need a whole new set of six pinion gears from Slauson Transmission.
First hard data that the turbo three rotor is too much for the C6 four pinion 
version. Any sign of overheating in the gears Tom?

Paul Lamar
 

 
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