Ed, The big sun gear is 2.25 inches in diameter.
so tooth torque  load is 200 foot pounds or 2400 inch pounds.
so the tooth shear load is 2400 inch pounds divided by 1.125 or
2,133 pounds. The same tooth load is applied to the ring gear teeth.

The 2.85:1 ring gear is 5 inches in diameter with a circumference of
15.7 inches. It is 2 inches wide so the area is 31.4 square inches.
Therefor the shear load is 2,133 pounds divided by 3.4 or 68 pounds
per square inch shear. Well within the capability of red RTV. In
other words we can just glue the ring gear to the housing with red
silicone rubber. Make a real thin aluminum steel RTV sandwich one
square inch in area and see how much load it will take in shear.

Your front planet shafts are the same size as mine. .440 or so.
The torque load on the bolts is 2.85 times 200 foot pounds or 570
foot pounds. That is 6840 inch pounds. Bolt circle is 3.3 inches.
Radius is 1.65 inches so total shear on the six bolts is 4,145
pounds. There are six bolts so each bolt must take 690 pounds shear.
If we EDM them out to 5/16 and use 5/16 bolts.  The bolt diameter
.3125. Pi X r squared for the area. Area is.0767 each bolt.
690/.0767 then bolt shear stress is then 8,996 in each bolt.

Piece of cake. Even cheap bolts will take 100,000 psi.

As a belt and suspenders we can add six 3/8th dowel pins between the
bolts. The 5/16th bolts will then just hold the works together.


Check my arithmetic.

Paul Lamar


Only 690lbs shear applied to each bolt? An 8 penny nail can handle that
load. So yes, a 5/16 or 8mm rod bolt ought to be plenty.

The best setup is the alum prop shaft with the planet cage machined on
one end. Use longer shafts, No bolts required.

Ed Carver

The cost of the shafts is the problem. They need to be hardened and
ground. Also NC machining the planet carrier is tricky and expensive.
The 5/16 bolts will work fine for the 2.85:1 and 3/8th for the 3.17:1.
They have an over design factor of around 10.

Paul Lamar
--

Hi, in flange type rotary joints the torque is transferred through the
matting surfaces through friction.  The bolts are loaded in tension to
supply sufficient contact force and thereby the friction to carny the
torque.  If the bolts are loose and loaded in shear they will usual fail.
If they are sufficient to carry the load in shear on paper they should be
able to provide enough clamping force if tightened enough.  Sufficient
contact area is also needed.  If you are familiar with the aircooled VW
flywheel mounting you will see the problems with pin type shear couplings
on engines.

Another old idea of mine, I think used by R-R in WW-I:  soft mount the ring
gear for torsional damping. Comments?

Murry I Rozansky