Stearman XA-21 Attack Aircraft
The Stearman X-100, designated XA-21 following purchase by the Army Air Corps, was a competitor in a United States Army Air Corps competition for a twin-engined attack aircraft which led to the Douglas A-20 Havoc, Martin A-22 Maryland and North American B-25 Mitchell.
Its initial design featured an unusual streamlined stepless cockpit arrangement. After testing, this was found to restrict the pilot’s forward vision, and the aircraft was rebuilt with a conventional nose and cockpit structure. Although this change in the cockpit did not significantly affect performance, the XA-21 was not ordered into production.