PARAMETRIC ANALYSIS AND PRELIMINARY DESIGN OF A SHAFT-DRIVEN ROTOR SYSTEM FOR A HEAVY-LIFT HELICOPTER
LOCKHEED-CALIFORNIA CO BURBANK
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A parametric analysis and a preliminary design study were conducted to determine the optimum characteristics of a shaft-driven rotor which would result in the lightest gross weight helicopter capable of lifting military loads in the 12- to 20-ton range. The study considered single- and tandem-rotor helicopters with internal cargo and cargo pod. Types of rotors analyzed were articulated, teetered, rigid, and matched-stiffness. Existing turbine engines or growth versions thereof were considered. Component weight equations were developed and a computer program was utilized to determine the rotor characteristics for each helicopter configuration. For a given set of rotor parameters, the program computed the power plant rating, fuel required, and the empty weight corresponding to the helicopter which would satisfy the most critical mission requirements with the minimum gross weight. The performance of the resulting configuration was determined. Design studies of the rotor system, rotor controls, rotorpropulsion arrangement, and the general arrangement were made. Rotor loads were developed and a structural design analysis of the rotor system, including fatigue and weight analyses, was prepared. A dynamic and aeroelastic investigation of the rotor system and a stability and control study of the helicopter were conducted. The study indicates that the single-rotor helicopter incorporating a matched-stiffness rotor system would have a gross weight of 62,500 pounds for 12-ton payload range and 74,727 pounds for the 20- ton payload range. These gross weights are 4- to 6-percent less than the other configurations studied.
- Transport Aircraft