Flexure having pitch flap coupling

Claim 1

A composite structure flexure having a longitudinal centerline for connecting a rotor blade having a chord line to a rotor hub in a bearingless rotor assembly, wherein the composite structure comprises fibers held together by a bonding agent, wherein reference Cartesian coordinates for said flexure are chosen such that an X axis is parallel to the longitudinal centerline of the flexure, a Y axis is parallel to the chord line of the blade, and a Z axis is perpendicular to the X and Y axes, wherein a plurality of said fibers are bonded in parallel co-planer relation in the XY plane to form a sheet, a plurality of said sheets comprising first, second, and third sets being bonded together in layers to form said flexure, the fibers of said first set oriented to form a positive angle with the X axis, the fibers of said second set oriented to form a negative angle with the X axis, the fibers of the third set being parallel to the X axis, whereby the resultant flexure allows limited three degrees of freedom of motiong of the blade to permit flap, pitch, and leadlag motion of the blade while inherently inducing a change in pitch angle of the blade in response to a change in flap angle of the blade.