In 1954 the first helicopters with rocket-driven rotors were flown; the Kellett KH-15 and Rotor-craft RH-1.
Nicknamed ‘Stable Mable', the KH-15 has been built for the U.S. Navy to test a new system oft gyro-abilisng cotrols. It flew after only 8 minutes of tethered tests. Power units are tip-mounted hydrogen peroxide rocket motors.
Power: 2 Reaction Motors XLR32 rockets
Rotors: 2-blade tip-powered main rotor and tail rotor
Rotor diameter: 18 ft
Loaded weight: 644 lb