Analytical Study of Helicopter Gust Response at High Forward Speeds
BELL HELICOPTER TEXTRON INC FORT WORTH TX
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An analytical study of helicopter gust response at high forward speeds is presented. A digital-computer program is described that includes rigid-body aircraft motions in space and the aeroelastic representation of two rotors. The rotors can be positioned to describe all general configurations. Various rotor types are considered, as well as compounding by the use of wings and auxiliary propulsion. Various maneuvers may be simulated, including subjecting the aircraft to gust disturbances. Results cover a wide range of forward speeds, disk loadings, blade loadings, and advancing blade-tip Mach numbers. The effect of Lock number on gust response is included. The relative importance of gust shape, gradual penetration, nonsteady aerodynamics, and gust- alleviation devices are discussed. A simple empirical expression is given that will adequately predict the rotor gust-load increase for a wide range of helicopter and compound designs.