Juan de la Cierva

Juan de la Cierva y Codorniu was a Spanish civil and aeronautical engineer who invented the autogyro, the first practical rotary-wing aircraft to achieve stable flight. After early fixed-wing aircraft projects failed, he turned to rotor-lift designs in 1919, and his breakthrough came in 1923 with an articulated rotor using flapping hinges that let each blade rise and fall independently, solving the stability problems that had defeated earlier rotorcraft attempts; his C.4 prototype that year became the first stable rotary-wing aircraft to fly successfully. He relocated to Britain in 1925 and founded the Cierva Autogiro Company with industrialist James George Weir, and in 1928 an autogyro of his design became the first rotary-wing aircraft to cross the English Channel. He received the Daniel Guggenheim Medal in 1932 and the Franklin Institute's Elliott Cresson Medal in 1933, and died at age 41 in the December 1936 crash of a KLM airliner near Croydon, England.