Mid-beam jointed reconfigurable bearingless main rotor assembly

Abstract

A mid-beam jointed reconfigurable bearingless main rotor (BMR) assembly that includes reconfiguration joints that facilitate BMR assembly reconfiguration by main rotor blade removal or folding to reduce the structural envelope of a helicopter for rapid deployment, routine transport, and/or storage. The BMR assembly comprises a rotor hub structure that includes a plurality of radially extending flexbeams, combinations of torsion flexure members and main rotor blades disposed in combination with corresponding flexbeams, and torque tube subassemblies disposed in combination with corresponding flexbeams and torsion flexure member, main rotor blade combinations. Each reconfiguration joint is formed by a combination of an outboard joint segment of a flexbeam and an inboard joint segment of the corresponding torsion flexure member. The rotor hub structure is fabricated so that the configuration joints are purposefully located at radial stations that are subjected to minimal flapwise loading, which for aerodynamic efficiency and manufacturing considerations should not exceed about fifteen percent of the overall span of the BMR assembly. The torque tube subassemblies are fabricated to provide access to the respective reconfiguration joints. For reconfiguration by the removal technique, each torque tube subassembly includes one or more access panels. For reconfiguration by the folding technique, each torque tube subassembly includes a removable splice tube.