Why is it important when dealing with flex plates?

http://en.wikipedia.org/wiki/Moment_of_inertia

"In classical mechanics, moment of inertia, also called mass moment
of inertia, rotational inertia, polar moment of inertia of mass, or
the angular mass, (SI units kg·m²) is a measure of an object's
resistance to changes to its rotation. It is the inertia of a
rotating body with respect to its rotation."

Also read gyroscopic forces.
http://www.gyroscopes.org/behaviour.asp

"When the gyroscope is spinning it can contain large amounts of
stored energy. Newton's first law of motion states that any body
will continue in its state of motion (still or traveling) until
outside forces change it. Because of the forces when the gyroscope
is spinning, if it is moved the gyroscope will try to 'compensate'
for this movement. If we take the example of a gyroscope's axle
being clamped to the structure of the car (often the cars engine
behaves as a gyroscope because of its shape, mass and rotations)."

"If the gyroscope/engine is spinning at a fairly high speed in a clockwise
direction, as seen from the back of the car and as shown in the diagram
above. When the car is turned to the right (clockwise from above)
 forces A and B are applied to the structure of the car forcing the
front end of the car down and the back end up. If the car is turned
to the left then the front end of the car is forced up and the back
end forced down. If the gyroscope is spinning in the opposite
direction then the reverse will happen."

"However if the car was moved directly upwards, downwards, forwards,
back-wards or side-to-side the gyroscope would not apply any extra forces.
The gyroscope only applies extra forces when the car is moved at an angle

(turning left/right or when the front/back of the car is moved
up/down). This effect is known as gyroscopic precession."

These forces go through the flex plate out to the ring gear stressing
the flex plate back  and fourth near it's hub thousands of times per
minute. In other words the ring gear attempts to continue to rotate
in it's original plain while the hub is being forced to change direction.

Paul Lamar

I agree that there is gyroscopic forces that affect the rotation of theflex
plate. Also included with that is the toque converter which has a much greater
mass. Any movement that would take place is held in check by the index hub on
the converter  that goes into the back of the e-shaft or crankshaft and the
bearing in the transmission pump. I am not sure the clearance of the bearing,
but 0.002" seems reasonable. That would imply 0.001 movement which would be
minimal flex in the flex plate. I am inclined to think the failures are due to
the torque pulses applied to the flex plate under high continuous power
loading. I believe you are right with the idea to make a flat disc of water
jet cut stainless and tack weld the ring gear on. Lightening holes aroundthe
outer diameter will not fail in my opinion. But then what do I know as a burnt
out mechanic :-))).

Dale Davies
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