Abstract: A helicopter rotor having opposed blades interconnected by a common flexible spar which passes across the rotor axis is connected to the drive shaft by clamped hub plates. A spanwise extending torque tube having a pitch horn at its inner end forms a rigid connection with the spar and blade at its outboard end. A centering bearing assembly is positioned at the inner end of the torque tube and spar to react control loads, centralize the torque tube about the spar, and provide pitch, flap, and lead-lag decoupling.

Abstract: A helicopter cross beam rotor is shown including upper and low coaxial composite blade spars at right angles secured by tension bolts which pass through the composite spars and are held by threaded nuts to a rotor hub at the upper end of a rotor drive shaft. A metal cap plate above the upper spar and a spar-to-spar filler piece are also provided. Torque between the spars and the rotor hub is reacted by intermeshing ribs and grooves on the confronting faces of the hub, the filler piece and the cap plate. The bolt holes in the composite spars are oversize so that the bolts do not react torque between the rotor hub and the composite spars.

Abstract: A helicopter main rotor which can be supported in two positions of elevation above the fuselage, and apparatus and method for moving the helicopter rotor with blades attached from a first elevated position above the fuselage wherein the rotor is supported from an extension shaft projecting from a first shaft to a second elevated position above the fuselage wherein the rotor is supported from the first shaft.