Improvements in Airplanes with Rotating Wings 18-04-1922 (application date) 01-01-1937 (expiry date) (Spain) 45 Pages on paper (application), 1 white and blue drawing on paper (plan); 21,2 × 34,1 cm Archives of the Spanish Patent and Trademark Office ES81406 Juan de la Cierva y Codorníu was born in Murcia, Spain in 1895. Interested in engineering from a very early age, he constructed prototypes of airplanes and helicopters along with a group of his friends. Together with his friends he built the BCD1 (‘Cangrejo’), the first Spanish airplane that can be said to fly. After some failures with traditional designs, Juan de la Cierva directed his attention to a different type of aircraft—these had rotating blades instead of fixed wings, allowing them to remain in motion at low speed. Thus he conceived the idea of autorotation, and he baptized this machine as ‘Autogyro . ’ It would take until January 1923 before the first sufficiently stable flight of C.4 was achieved, after which Jua...