An auto-gyro is a type of light rotary-wing, similar to a helicopter. Unlike the helicopter, the auto-gyro’s rotors depend on aerodynamic forces to provide lift, rather than an engine driven rotors, while an engine driven propeller is used to thrust to the aircraft. The engine can either be a pusher or puller type of arrangement, just as with standard fixed-wing aircraft.This is a Kellett_KD-1 operated by Eastern Airlines is perhaps the type used by Doc Savage-leastwise according to Marvel Comics. ==Development== ==Variants== ;KD-1 :Prototype, one built ;KD-1A ;KD-1B ;YG-1 ;YG-1A ;YG-1B ;YG-1C ;XO-60 }}