The Servo-Flap Rotor and Aircrew Survivability

In the event a helicopter in flight suffers a total power loss, autorotation is the one and only option that a pilot has to insure helicopter survivability. While many advances have been made in helicopter crashworthiness, this paper addresses the most critical stage of an autorotation, the entry. A successful autorotative entry often depends on pilot reaction time and rotor system design. Parameters such as inertia, rotor decay, and controllability are addressed. A comparison between a sample single rotor design and the design’s of the Kaman servo flap rotor helicopters are compared. In particular, the Intermesher K-MAX and the single rotor Kaman H-2 design are analyzed in regards to rotor decay, inertia, servo flap characteristics, and aircraft response to a sudden and total power failure.