Drag racing is a long way from aircraft use.
 I am highly concerned the aluminum flywheel will crack
 around the mounting bolts.

 Please Dave, inspect it on a regular basis.
 especially after a race.

 Paul Lamar


Along these lines...  I was just pondering the relative weight (moment
of inertia - rotational) of what's bolted to the e-shaft when
installed in a car.  In a car, the e-shaft is hard bolted either to
the flex plate, and then the torque converter, or to the flywheel and
then pressure plate.  In both cases, it's probably in the neighborhood
of 20lbs.  My impression is that both of these are much heavier than
what's provided by Tracy's setup.  That may make life easier on the
e-shaft, but may be making life harder for everything downstream
(towards the gearbox).  We aren't trying to speed shift..  A light
flywheel makes an engine more responsive to heel-toe blipping
downshifts, and zippy upshifts.



I don't think 2G's in the turn is the big load on the flex plate.  The
loading is largely in the plane of the flex plate..  Heading isn't
changing very rapidly.  The heavier load would come from spinning the
airplane - rapid yawing in a different axis from that of the e-shaft.
Flat spins and snap rolls - all yawing maneuvers with potentially high
RPM.  Right?  It's been so long since I was in Physics I that it might
take me a while to work out the math, but I'm pretty sure the gyro
loading is going to cause a much larger bending moment on the flex
plate..



Thoughts?


Matt-

Yes you are right Matt. It may be the two torque pulses per rev.
As the flex plate is directly exposed unlike the PSRU.

Especially since Mark S Tx is seeing the same thing with three torque
pulses per rev.

Paul Lamar

In an auto installation it would appear the flex would be severely
constrained as the torque converter would transfer loads to the input
shaft of the transmission, preventing excursions of more than a few
thousandths at the ring gear.  Essentially in the auto the flex plate is
supported between two bearings on a rigid shaft
Tracy's rubber dampers free the plate to flex in the aircraft, leading
to large excursions as it is unsupported except for the e-shaft
attachment.  It would appear a substantially stiffer plate would be
called for

Victor Roberts