Helicopter Lift Margin System and Low-Speed Performance Evaluation NUH-1M Helicopter.

摘要

The United States Army Aviation Engineering Flight Activity conducted an engineering flight evaluation of a helicopter lift margin system installed in an NUH-1M aircraft. The Trans-Sonics, Inc. helicopter lift margin system tested is a special-purpose sensor and computer system designed to continuously compute and display performance margin in terms of excess hover thrust available (lift margin). The prototype system evaluated approaches an operationally adequate system and represents a significant improvement over previous methods of presenting performance information. Fifty-eight productive flights were flown from 28 September through 23 December 1973 and from 25 June through 10 September 1974, resulting in 31 productive test hours. Tests were conducted at Edwards Air Force Base, Oxnard, Bishop, and Coyote Flats, California, to obtain a large variation in ambient conditions. Correction of the four deficiencies would result in an operationally suitable system. The deficiencies were: (1) lack of consideration of low airspeed (wind) and its effects, (2) the requirement to hover out of ground effect prior to having lift margin available, (3) lack of a comprehensive failure warning, and (4) inadequate range of operational conditions considered in the design.