CIERVA JUAN DE LA: (1895-1936) Spanish Aeronautical Engineer. Inventor of the “Autogiro”, the world's first successful flight of a rotary-wing aircraft . An original 4to pen and ink drawing by the German-Swiss artist Robert Kastor, the well executed work depicting De la Cierva in a head and shoulders pose. Signed by the Spanish inventor `J. de la Cierva´ and dated Madrid, July 1921 in his hand. VG, £80-100.

De la Cierva’s work on rotor dynamics made possible the modern helicopter. Autogiros were built in many countries under his licenses, including France, Germany, Japan, Russia and USA. The understanding that he established is applicable to all rotor-winged aircraft. De La Cierva died in an airplane crash.