Here is what it looks like with a 3 inch inner tube and socket
     head metric 10 mm bolts. I think this is an improvement but
     we can still test what we have. This is a minor change in the
     over all scheme of things.

     Paul Lamar

     That works too.  My thought was to extend the three "paddles".  By
     extending the paddles, there is more space for the silicone.

     FWIW - From looking at the welded up assy, I don't see how this little
     assy will be able to absorb 350 hp.

     Mark

 Two ways to get HP. Torque or RPM.
 The rotary is RPM. Lets say it generates 350 HP at 7500 RPM.
 What is the torque?

 HP = T X RPM /5252
 350 = T X RPM / 5252
 350 X 5252 / 7500 = T = 245 foot pounds.
 3000 inch pounds. Divided by 5 inch diameter = 600 pounds total force.
 3 rubber lumps 200 pounds per rubber lump.

 One inch high by 1.4 inches is 1.4 square inch.
 142 psi.

 It is hard to quantize rubber for compressive strength
 because it expands in other directions 90 degrees to the load.
 The tear strength is 580 pounds per square in or about 4 MegPas.

 Cut 4 pieces 1 inch by 1 inch. One square inch. Stack them up on the
 floor. 3/8th of an inch thick roughly. Best to glue them together
 with red RTV and let it cure for 24 hours.

 Put the heal of your shoe on the rubber stack and balance with on foot.

 See if it springs back to shape.


 Paul Lamar

Hey Paul,

I think I see an error in your calculations.

245 foot pounds = 2940 inch pounds
2940 inch pounds divided by 2.5 inch radius = 1176 pounds force
1176 pounds force divided among 3 rubber lumps = 392 pounds force per
rubber lump.

How much clearance is required through the center of the torque damper?
 Your pictures scale to about 1" ID clear hole.  Is that correct?

  Mark LaPierre

Yes. You are right. There are only three compressions chambers.

There are also three tension chambers. If we use liquid
and it bonds in the tension chambers the stress on the compression
chamber is half that. The max tensile stress for curred silicone rubber
is 580 psi. BTW this is the same stuff they use to bond glass plates
together to make fish aquariums. It is very strong as a glue
in tension.

The latest version gives a void of 2.75 inches in diameter.
That is with a inner steel tube cylinder of 3 inches OD.
Some of that is taken up with the 2" dia. spline plate and some is taken
up by the roughly 1 inch diameter gear box input shaft that pilots in
the eccentric shaft. Just like a manual transmission.


Paul Lamar