 the hydra 70 rocket is a weapon derived from the 2.75 inch mk 4/mk 40 folding-fin aerial rocket developed by the united states navy for use as a free-flight aerial rocket in the late 1940s. ==overview== the hydra 70 family of wafar (wrap-around fin aerial rocket), based on the mk 66 universal motor, was developed from the previous 2.75&nbsp;inch mk 40 motor-based folding fin aerial rocket. the propellant grain is longer and of a different formulation than that of the mk40/mk4, however, the stabilizing rod and igniter are essentially the same design. the mk66 motors have a substantially higher thrust,  (mod 2/3)  (mod 4), and a longer range than the older motors. to provide additional stability the four rocket nozzles are scarfed at an angle to impart a slight spin to the rocket during flight. the mk&nbsp;40 was used during the korean and vietnam wars, being used to provide close air support to ground forces from about 20 different firi
Air-to-ground_rockets_of_the_United_States Cold_War_rockets_of_the_United_States