Dynamical Design Of Ski Landing Gear

Ski landing gear has a simpler structure and lighter weight which is mainly used in snow and sand landing conditions, or some low-landing-speed aircrafts don't need wheel landing system. A kind of ski-landing-gear is needed for a UAV (unmanned aerial vehicle) according to the design of UAV. In this paper the general design process was raised referring to the common landing-gear design handbook, then the basic of the ski-landing-gear according to the UAV landing kinetic energy was designed and the right structure material and finally honeycomb was chosen as cushioning material.A non-linear FEM model the ski landing gear was made based on preliminary design and simplified UAV fuselage. In the model the fuselage was simplified as a cylinder but the gravity center was in the right place. The honeycomb was also simplified as non-linear according to the material compressive properties. After the simplifications the computational efficiency was seriously improved.The landing simulations were carried by MSC.Dytran. Considering many landing conditions 16 simulations were carried. After simulation UAV overloads and buffer trips which are main landing parameters were calculated, according to former parameters the buffer parameters were fixed until these parameters met landing requirements. After that the biggest moments on landing-gear pillars and skis as well as the force on skis and putlog connected the skis were calculated, according to which the structure was modified.After the modification a series of emergency landing simulations with bigger UAV weights were carried, the analysis report showed that the fixed was sate in emergency landings.