Investigation of Engine Rigging, Airspeed and Rotor RPM Effects on Steady State Autorotational Performance.

摘要

An investigation was conducted to define the effects of various airspeeds,rotor speeds,engine rigging and gross weights on a UH-1C helicopter during autorotation. Results of the investigation confirmed previous qualitative conclusions: that the use of low rotor speed to obtain maximum glide distance can be hazardous,especially at high gross weight conditions;and that current autorotation rate of descent information in operator's manuals is insufficient for the operator's use. The investigation further revealed that with a normal engine rigging,there is a measurable amount of engine output torque at low rotor speeds (310rpm and below) during practice autorotations. This situation,encountered in a training environment,could produce a false sense of security in an individual faced with an actual emergency. Although the operational pilot cannot duplicate controlled test conditions,he should understand normal performance limits and the consequences of exceeding those limits. The report furnishes UH-1C autorotational data not currently available to the operator which should be incorporated into the appropriate manuals. (Author)