At Deere and RPI, (snip)

and all auxiliary systems were provided by the test stand, for

example coolant and oil pumps were electric independent systems.)

 In other words the amount of oil provided to the rotor was independent
of the engine rpm and therefore any difference in balance would not
be noticed with rpm change.....

We balanced

engines using only the weight of the rotor (not the oil contained within the
rotor), and the singles did not exhibit any "shake" whatsoever. Very smooth.

 The people at places like Racing Beat and others should take note and stop adding
weight to account for oil in the rotors!?

Torque fluctuations would not be noticed because of the extremely

large mass

of the electric dynamometers.

And a stiff mounting of the engine so that it's rotational "shake" is transmitted
to the dynamometer mount. OR the rpm's were high enough
that the rotational inertia of the engine could not respond to the torque
variations.

I strongly believe that if a single rotor

engine exhibits any external non-torsional vibration it is not properly
balanced.

The Key word here is "non-torsional" i.e. when the engine it self rotates
(as in my case) it is torsional.

The reason we did not account for the oil in the rotor is because

theoretically there should be very little oil in the rotor at any given time.

 Sketches provided in Norby's book on the development  of the rotary
engine, suggest measurable amounts of oil in the pockets at the apex
of the rotor.(pg # 57)

The motion of the rotor expels the oil more rapidly than it enters, hence
there is only (theoretically) a thin film of oil on the metal surfaces. Too
much oil would interfere with cooling and also would cause pumping losses.

Jon Lauter
Rotary Power Marine Corporation
www.rotarymarine.com

 My conclusion is that your test setup could support your observations,
but the set up for an instillation in an aircraft, i.e. resilient mount
isolation to a non massive mount structure, driving a  prop, 50" diam.
by 42" pitch, wooden, in my case, would yield different observations.

 The magnitude and duration of the negative torque pulses are real
and significant and can not be ignored if longevity of a Gear
Drive system is desired. Most A/C engine builders would not
apply a 30 lb flywheel isolator between the engine and gear drive,
and the duration of the negative torque would transmit through all
of the existing redrive isolaters I have seen.

Rodger

A thirty pound flywheel is not what I am suggesting Rodger. Try a 
softer rubber coupling similar to what Tracy is using and/or 
a metal prop. I agree it might drive through at low RPM.
Idle it faster. So it would maybe not make a good sea plane engine.

Have you been in an O-360 powered airplane? They are not
the smoothest things in the world either.  Especially when
starting up and shutting down.

Paul Lamar
 
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