초록 ▼

A controllable lifting rotary wing for an aircraft wherein each rotor blade is mounted in such a manner that it has freedom to oscillate in pitch about its feathering axis. The aerodynamic center on each rotor blade is displaced forward of this feathering axis over at least a portion of the span. Cy

A controllable lifting rotary wing for an aircraft wherein each rotor blade is mounted in such a manner that it has freedom to oscillate in pitch about its feathering axis. The aerodynamic center on each rotor blade is displaced forward of this feathering axis over at least a portion of the span. Cyclic aerodynamic forces on this spanwise portion cause the blade to change pitch sinusoidally once-per-revolution of the rotor whenever the rotary wing aircraft experiences a change in flight attitude or velocity. The result is that the rotor blades automatically and continuously change pitch to cancel out cyclic lateral flapping moments which are normally produced on a helicopter rotor blade by such a flight disturbance. This rotary wing has greatly improved stability by virtue of this self-feathering action. Cyclic pitch control moments are applied to the rotor blades by indirect means which do not interfere with automatic blade feathering. Means for control of collective pitch of the blades are also provided.

대표청구항 ▼

A lifting rotary wing comprising; a hub mounted on a shaft, and a number of lifting rotor blades mounted to the radial arms of said hub by bearing means for feathering displacement about a spanwise pitch-change axis, Wherein said pitch-change axis of each lifting rotor blade is a first spanwise line

A lifting rotary wing comprising; a hub mounted on a shaft, and a number of lifting rotor blades mounted to the radial arms of said hub by bearing means for feathering displacement about a spanwise pitch-change axis, Wherein said pitch-change axis of each lifting rotor blade is a first spanwise line in the blade which passes through the centers of gravity of all spanwise blade segments, and each blade has a second spanwise line which passes through the aerodynamic centers of all spanwise blade segments, said aerodynamic center line coinciding with said pitch-change axis except in a spanwise portion of the blade between radius r1 and r2 where the average chord is cx and the aerodynamic center line is located an average distance dx forward of the pitch-change axis, and moment of inertia of the blade IB measured about the blade pitch-change axis is related to the dimensions of said spanwise portion of the blade by the relationship [Figure] Where r