The 1928 Alfaro X-13 NX7647 was an entry in the Guggenheim Safe Aircraft Competition. A two-place powered by a 110hp Warner Scarab, the variable-lift wing featured spoilers, and a trailing-edge flap that contained a shutter to seal the gap between the wing and flap. Did not qualify because of its lack of slow-speed control, and failure to meet the required maximum speed of 110mph.
Also seen as Ingalls Safety Airplane.
All Aero 