Bladed aircraft rotor with flexible blade mountings

Claim 1

A bladed aircraft rotor comprising a rotative hub structure and a plurality of blades radiating from the hub structure, the hub structure including a driving shaft and a blade mounting ring surrounding the shaft, each blade having a flexible mounting strap connecting the blade with said mounting ring and providing freedom for flapping and pitch change motions of the blade with respect to the mounting ring, the driving shaft having means defining upper and lower bearing surfaces concavely spherically curved about a point on the axis of rotation of the hub structure, and the blade mounting ring having means defining upper and lower bearing surfaces convexly and concentrically curved about said point on the axis of rotation, flexible elastomeric means between the concentrically curved bearing surfaces for transmitting centrifugal thrust forces from the blade mounting straps to the hub structure while permitting blade motion substantially in a plane containing the axis of rotation of the hub structure, and means for transmitting torque force between the hub structure and the blades comprising flexible bellows above and below the blade mounting ring interconnecting the blade mounting ring with the drive shaft above and below the blade mounting ring, wherein the bellows serves mainly to drive the blades.