Paul,
Perhaps you can me get a better understanding here. The case hardened drive
shaft from the RX-8 going into the manual clutch plate don't appear to be
much bigger in diameter that the 25 year old RX-5 transmission drive shaft I
have. The older engine was good for about 160 Hp but we see the RX-8
hopped up to over 300Hp or more in some cases. Hmmmm??? Were the old
transmission drive shafts which tapers down from 1 1/4" to a 3/4" spline at
the clutch plate just over designed?
I notice both Tracy and Mistral have about an 1 1/4" diameter male spline
on their sun gear shafts and Mistral also provides and important centering
shaft that inserts into the e-shaft. (See last picture)
Q. Because of flywheel effect of the prop and gearing of the PSRU, is it
correct to assume the shearing loads the sun gear shaft will experience are
much greater than what the automobile drive train will put on the
transmission input drive shaft? I believe the answer is yes.
Thanks
Doug Fir.
I don't know? Did you calculate the torsional stress
at 220 foot pounds? Perhaps it handled the increase from 160 foot
pounds to 220 foot pounds.
Typical drag race driving practice is to rev the engine to 7000 RPM
and step off the clutch. Car magazines do this all the time to get
the best 0 to 60 times. The rotational inertia stored in the
engine and flywheel is enough to break traction on wide
rear tires for ten or twelve feet. Compared to that accelerating
a prop is a piece of cake.
In some case guys change the transmission.
http://physics.uwstout.edu/Statstr/statics/Torsion/tors51.htm#Topic%205.1:%20
Torsion:
max stress = T R/J
where T (inch pounds) is the internal torque in that section of the shaft,
R = maximum radius of the shaft(inches), and J = polar moment of inertia.
J = (Pi/32) d^4 for a solid shaft, and J = (Pi/32)(do^4 -di^4) for a
hollow shaft, where do = outer diameter and di = inner diameter. In inches.
The static shearing stress will not change due to loads. It is only a function
of what torque the engine can put out. The dynamics on the other hand
are an entirely different matter and that is where the torque fluctuation isolation
plate comes into play.
Paul Lamar ...No rotor no motor.
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