The pilot said that while on short final, the airplane experienced a sudden sink rate when the wind went from a head wind to calm conditions. He was unable to arrest the sink rate even after power was applied because of the lag time for the airplane’s turbine engine to spool up. The airplane landed hard, short of the runway. After taxiing to the ramp, examination of the airplane revealed that the left side of the fuselage was dented and wrinkled, and the left main gear was found bent inboard of the axle and its brake assembly was missing.