Abstract: A helicopter rotor having a rotor hub and a plurality of rotor blades includes for each blade a blade fold mechanism comprising a reversible rotary power source and a rack and pinion mechanism adapted to operate one or more lock pins and to fold the blades between an operational spread position and a folded position. Two embodiments of the invention are described and illustrated.

Abstract: A helicopter rotor includes a rotor head arranged to support a plurality of rotor blades for rotation about an axis. The rotor head comprises a generally hollow structure, and each rotor blade is supported by an elastomeric bearing arranged to permit blade flap, lead/lag and feathering movements. A resilient support means is housed within the structure and is operatively associated with each rotor blade so as to provide controlled restraint of rotor blade movements in the blade flap plane. In the illustrated embodiment, the support means comprises interconnected inner and outer elastomeric assemblies, the outer assembly being connected to each rotor blade through a common elastomeric lead/lag damper unit which provides inter-blade damping of blade lead/lag movements. The outer elastomeric assembly also provides an automatic blade droop stop.

Abstract: A helicopter rotor includes a rotor head having, for each of a plurality of rotor blades, an elastomeric bearing and a damper that is arranged to provide controlled restraint of rotor blade movement in both the flap and lead/lag planes. The damper can be arranged to exhibit either substantially equal stiffness in both operational planes or any desired stiffness ratio. In a preferred embodiment of the latter arrangement, the desired stiffness in the respective planes are provided by separate components incorporated in the single damper. The damper may be situated either inboard or outboard of the elastomeric bearing.