UNITED TECHNOLOGIES CORP STRATFORD CT SIKORSKY AIRCRAFT DIV
An analytic study was conducted to assess the suitability of a conformable rotor for satisfying the requirements of a typical Army mission. A conformable rotor blade is a blade designed to produce changes in blade twist, with azimuth and flight condition, which improve performance and reduce rotor loads. This study quantified the performance advantages and rotor system load reductions possible with a conformable rotor by designing blades suited for the UH-60A mission and comparing calculated rotor behavior with that of the UH-60A rotor. Relative to the UH-60A design, the conformable blade employs a four-to-one reduction in torsional stiffness over the outer half of the blade a reduction in built-in twist from -16 to -12 degrees, an increase from 20 to 30 degrees in tip sweep and reflex tab deflection inboard of the 80-percent radial position. This design produces elastic response which increase twist in hover and reduces advancing blade twist in forward flight.