At Deere and RPI, we used single rotor "rig" engines extensively for
development testing. (Rig engine means that it was basically just a power
section, and all auxiliary systems were provided by the test stand, for
example coolant and oil pumps were electric independent systems.) 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.

Torque fluctuations would not be noticed because of the extremely large mass
of the electric dynamometers. I strongly believe that if a single rotor
engine exhibits any external non-torsional vibration it is not properly
balanced. 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.

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

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