Advanced Technology Helicopter Landing Gear Preliminary Design Investigation
Final rept. Sep 83-Jul 84,
HUGHES HELICOPTERS INC CULVER CITY CA
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This report describes the preliminary designs of two configurations of helicopter crashworthy landing gears 1 with the trailing arms of the main gear coupled wth a torque, which forces both shock struts to absorb the kinetic energy of an unsymmetrical crash impact, and 2 with the trailing arms uncoupled i.e., the torque tube is replaced by a cross tube which is incapable of reacting the high torsional load of an unsymmetrical crash impact. Retractable and fixed landing gears of both configurations have been designed, as well as a standard noncrashworthy retractable landing gear. All landing gears are of tailwheel designs. The designs apply the systems approach to crashworthiness where the total impact energy absorbed is shared by the landing gear, fuselage and seat. The designs of the crashworthy landing gears were completed after a preliminary investigation of crash impact at sink speeds up to 42 fps, roll angles up to or - 20 degrees and pitch angles up to -1020 degrees. The crashworthy evaluations were made with program KRASH. A detailed analysis with KRASH was then conducted for all configurations of landing gears. Based on the weight trend curves and cost analysis, a crashworthy design criterion was recommended. This design criterion was the basis for updating the landing gear design. The designs identify the fabrication methods and processes for the landing gear. Estimates of cost and weight of the updated designs are also presented.