He was interested in flight as a teenager and experimented with gliders with his friends. After receiving his engineering degree, in 1918 he built the first trimotor airplane. Its crash in 1919 after a stall convinced him that aviation safety called for stall-proof aircraft that could make steep takeoffs and landings at slow speeds. He decided that only the wing and not the body should be used to maintain lift. He began experimenting with rotating-wing aircraft in 1920 and developed the autogiro as a more stable form of aircraft. His first attempts with rigid rotors were unsuccessful. He then applied the idea of mounting the blades to the hub of the rotor on hinges so they could flap. This would equalize lift on advancing and retreating sides of the rotor while in forward flight.
His first successful flight with the autogiro took place on
Cierva moved to