Helicopter Ground Resonance: The Effect of Rotor and Fuselage Damping

The equations of motion developed by R. P. Coleman have been evaluated for a particular helicopter configuration and a large number of different combinations of rotor and fuselage damping. These results are displayed graphically and reveal the dependence of the unstable range on rotor and fuselage damping. Some of the conclusions are in disagreement with those reached by Coleman. Both viscous and friction rotor dampers are considered.