Contoured flexure strap for helicopter rotor system

摘要

The present invention relates to an improved helicopter rotor system including a contoured flexure strap having a simplified geometrical configuration. The flexure strap serves to join the rotary hub assembly with the rotor blades and is formed of fiberglass. The primary load carrying fibers of the flexure strap preferably extend in the same direction as the spanwise axis of the flexure strap in order to withstand the centrifugal forces acting on the strap. The inboard end portion of the flexure strap includes two separate ends, with one of the ends extending in a vertically upward direction and the other end in a vertically downward direction. This allows the ends of flexure straps positioned on opposite sides of the rotary hub assembly to overlap one another and be retained in place by a single pin and bolt assembly. A cloth wrap of composite matrix material surrounds portions of the flexure strap to provide redundancy which prevents the fibers in the flexure strap from delamination when subjected to forces arising during operation of the helicopter.