Contrarotating helicopter rotor - has head mechanism which drives fixed pitch high speed upper airscrew and lower helicopter rotor

摘要

The helicopter rotor head provides contrarotating drive to an upper, small diameter, fixed pitch airscrew (78) and a lower helicopter rotor. Drive from the engine is transmitted by a central shaft (70) directly to the airscrew and then through an epicyclic reduction gearbox (54) to a concentric tube driving the rotor blades. A free wheel mechanism allows the free rotation of the rotor if the main drive should fail. The mechanism also forms a friction disc torque limiter which allows the airscrew to turn if the rotor is stopped for any reason. A rotating housing is flexibly supported and can be tilted relative to the fuselage by an arm extending into the cockpit. This causes the rotor plane to tilt but not the central bearing which supports the blade shaft ends.