Abstract: A flexbeam helicopter rotor having an improved connection between the flexbeam and the hub of the connecting pin variety but in which the high tensile fibers of the flexbeam do not wrap around the connecting pin, wherein the blade centrifugal loads and the blade lead-lag loads are reacted by the connecting pin at a station where it passes through drilled holes in the flexbeam inner end, and wherein the blade flapping motion imposed loads are reacted through two load paths in the flexbeam-to-hub connection, the first load path being created by a prying reaction between the flexbeam and the hub connecting flanges, and the second load path being created by the differential bending reaction between the flexbeam at the station of the drilled holes and the connecting bolts.

Abstract: An improved clevis joint capable of withstanding substantial pivotal motion between its joined members and loading along its axis. An improved clevis joint wherein the parts joined thereby are pivotally connected by two sets of elastomeric bearings which are free to rotate about the joint axis and which envelope and support a free floating centering pin from the joined members so that during motion between the joined members, said elastomeric bearing sets share the rotary motion due to the rotating of the connecting pin.

Abstract: A pitch retention member has a mounting surface which receives an elastomeric bearing disposed within a coupling attaching to the root end of the propeller blade. The mounting surface of the pitch retention member is conical. The coupling has a conically shaped bearing mounted therein which is bolted to the root end of the propeller blade. By bolding the coupling to the spar the conically shaped elastomeric bearing is precompressed against the conical mounting surface.

Abstract: A hybrid metal composite rotor hub retention plate having high strength and reduced weight. The retention plate comprises a metallic perimeter support structure and a plurality of metallic spokes that extend inwardly from the perimeter structure to a hub. The perimeter structure, hub and spokes define at least three holes. The perimeter structure and spokes have upper and lower surfaces. Fiber reinforced resin matrix composite capable of reacting to bending loads, in-plane shear and axial loads is bonded to the upper and lower surfaces. The hybrid metal composite rotor hub retention plate is made by forming the metal structure and using the metal structure as a mold for the fiber reinforced resin matrix composite.

Abstract: A two-step composite joint that has improved strength to withstand both axial and bending loads. The joint comprises two articles each comprising a filler layer disposed between first and second composite layers. An end section of the first article's first composite layer is disposed external to, overlapping and bonded to an end section of the second article's first composite layer to form a first overlap. An end section of the second article's second composite layer is disposed internal to, overlapping and bonded to an end section of the first article's second composite layer to form a second overlap. The first overlap is displaced across the thickness and along the length of the joint from the second overlap. Loads are transferred across the joint from first layer to first layer and from second layer to second layer.

Abstract: The present invention discloses a damage tolerant composite article comprising a plurality of layers of both graphite and polyaramide fibers. The graphite fiber layers are oriented at angles of about .+-.30.degree. and about .+-.15.degree. to the longitudinal axis while the polyaramide fiber layers are oriented at about .+-.14.degree. to the longitudinal axis. Composite structures of this construction will have increased damage tolerance while maintaining the required bending and torsional stiffness.