摘要: This report describes the development of retractable, crashworthy, main landinggear system for an LHX-size helicopter. The landing gear is of a tricycle configuration and is designed to absorb 60 percent of the energy from a 42 fp... 展开 This report describes the development of retractable, crashworthy, main landinggear system for an LHX-size helicopter. The landing gear is of a tricycle configuration and is designed to absorb 60 percent of the energy from a 42 fps level impact condition. The landing gear extends automatically in less than two seconds in an emergency. In the event that the hydraulic and electrical systems fail, the gear is extended with the hydraulic accumulator that primarily supports the helicopter APU. Five sets of landing gears were fabricated in the program. The tests included single-gear platform drop tests with level and simulated roll and pitch conditions, and combined pitch (+15 deg) and roll (10 deg) conditions with an iron-bird fixture simulating a helicopter. The tests were conducted for five impact velocities from 10 to 42 fps. The crashworthiness analyses were conducted using program KRASH. The correlation between test and crashworthiness analysis results was very good and demonstrated how analyses can be used to predict the response of landing gears without utilizing expensive tests. The cost of 5000 shipsets over a 13-year production cycle has been projected from the cost of landing gears fabricated in this program. Keywords: Drop tests, Energy absorption. (Author) (KR) 收起