Rotors for rotary winged aircraft

Claim 1

A rotor hub for a rotary winged aircraft including a central fixed component and an outer rotatable component, at least two blades mounted at their respective roots on said rotatable component and a cyclic pitch control comprising a spider connected to the roots of the blades and means, associated with each of the blade roots, for varying the blade angle of attack of each blade of a rotor as each blade rotates around the path traced out by the rotor to bring about a non-sinusoidal cyclic pitch change whilst independently allowing a sinusoidal cyclic pitch control to be superimposed thereon through the medium of the spider, said means for varying the blade angle of attack of each blade comprising a spindle attached to each blade said spindles being equidistantly mounted for rotational movement with the rotatable component of the hub and a plunger engagable at one end with the respective blade said plunger being mounted on the rotatable hub component for rotation therewith and linear movement relative thereto and engaging at its other end a cam whose outer periphery is a predetermined peripheral profile, said cam being movable axially of the hub component, said plungers being connected to sinusoidal cyclic control levers mounted on the spider and said levers being splined to said plungers so that axial movement of the plunger initiated by the cam does not interfere with the sinusoidal cyclic control lever, whilst tilting of the spider to rotate the plunger does not impose any axial movement thereupon.