Hey, Paul.
I have made a basic disassembly of the RD1-C in preparation for the lightening
process. I have measured the wall thickness supporting the ring at .600". If I
recall, your recommendation was to cut out .500"? That would leave only .1" of
support for the ring. Just checking before we start cutting that that is enough.
Also what would you recommend for the resulting flange depth?
I will apply the same numbers to the supporting base ring?
I notice in the drawing showing the "PT-6" style torque meter, did you spec a
part number for the torque meter? while I'm in here that would be an interesting
and useful addition.
Thanks for your help.
C. Smith

If you do a stress check .1 inch wall certainly looks like enough
but if the sand casting is less than perfect that might be
asking for trouble.  Use .2" to be on the safe side for both the
wall and the flange.

The torque meter is built in to the helical sun gear.
There is a axial reaction force on any helical gear.
This reaction force is directly proportional to the torque
the gear is transmitting. One way of measuring it is
with an annular hydraulic cylinder. The same thing is now
used to disengage manual transmissions. The space in there
is limited so it probably must be custom made.

Here is a better 3D on the subject.

Paul Lamar

Thanks, I'll skip the custom made thingy.
On another note, after studying the various drawings, I see you have shown that
this can be modified for a CS prop gov. Now that doesn't look much more
complicated. Can you provide any more details on this mod? Orafice of added
restrictor, (there are already thrust roller bearings provided with the unit, is
there more to do?) the end plug can be driven out, the shaft is ported already
3" up from the end, use existing oil inlet for prop gov, any thing else i
missed?
I did not realize that this could be so easily adapted to standard aircraft CS
prop. But then again, isn't the standard CS prop and hardware heavier (50/55
lbs) than the vari-prop system (35/40 lbs)?
Just mulling over the pros and cons of each system now.
C. Smith

The prop flange is not suitable for a CS prop so an adapter
would have to be made. Then the shaft and bearings are
suspect for a typical 50 pound constant speed prop.

The gov would have to be cog belt driven of the front
of the e-shaft.

Paul Lamar