Patent ID: 8668162

Claim:
A method for operating a rotary wing aircraft comprising: impelling the aircraft in a forward direction at an airspeed by means of a thrust source, the aircraft having secured thereto a rotor comprising an even number of blades secured at equal angular intervals around a rotor hub rotationally mounted to the aircraft, the rotor operable to rotate about an axis of rotation; and rotating the rotor at an angular velocity with respect to the aircraft such that each blade is alternately moving in a retreating direction and an advancing direction with respect to the aircraft, the retreating direction having a component opposite the forward direction and the advancing direction having a component in the forward direction; wherein the angular velocity and airspeed are effective to cause a positive total lift on each blade due to air flow over the blades in the retreating direction when the blade is moving in the retreating direction, wherein each blade defines a pitch angle relative to a direction of blade movement, the method further comprising: cyclically modulating the pitch angle effective to cause a bending moment induced on the blades when moving in the retreating direction due to lift to be equal to between 0.3 and 0.7 times a bending moment induced on the blades when moving in the advancing direction due to lift.