Cierva, Juan de la (1895–1936)

Spanish engineer. In trying to produce an aircraft that would not stall and could fly slowly, he invented the autogiro 1923, the forerunner of the helicopter but differing from it in having unpowered rotors that revolve freely.

Cierva was born in Murcia and studied engineering in Madrid. He was twice elected to the Cortes (parliament), in 1919 and 1922. In 1925 he founded the Cierva Autogyro Company in the UK. Test-flying his own aircraft, he was killed in a crash in Croydon, South London.

Cierva's first aircraft was a biplane bomber which stalled and crashed when tested 1919. It occurred to him that a machine with a rotating wing would be less vulnerable to engine failure, and he developed the autogiro. Commercial production began 1925, and in 1928 he flew one of his company's aircraft across the English Channel. He then flew one all the way to Spain.