The "autogiro"
This is a 1923 photographic record of Juan de la Cierva's autogiro rotorcraft tests, published as a NASA Technical Reports Server scan for aviation engineers and historians. The plates are black-and-white photographs of prototypes numbered No. 1 through No. 4, showing the rotor head, landing gear and airfield settings. A designer could take from them the stark, documentary look of early 1920s aircraft photography, with its high-contrast outdoor grass fields, crowds and hangars, and the mechanical silhouette of the spinning rotor blades.
