The XB-35 was the first Northrop flying wing bomber design. The initial contract for a single aircraft was awarded in November 1941 and amended to include another in January 1942. Extensive engineering work was necessary (and planned) so Northrop was awarded a contract in October 1941 to build four smaller flying wings under the designation N-9M. It was hoped that flight data gathered from the N-9Ms would speed the development of the B-35 project.
Although the N-9M data was valuable, the XB-35 program was hampered by a series of delays while engineering problems were solved. An order for 13 YB-35 service test aircraft was placed in September 1942 and another order for 200 production B-35Bs was placed in June 1943. It soon became apparent, however, that the aircraft would not be ready in time for use in World War II. Furthermore, jet bomber prototypes already on the drawing board made the propeller driven XB-35 obsolete before its first flight. The Army decided to continue the B-35 program, but only in test status. The B-35B order was canceled and the YB-35 order was amended to include conversions to jet powered aircraft (YB-49 and YRB-49A). The development of the XB-35 continued but at a slower pace, and the first flight of the XB-35 (S/N 42-13603) wasn't made until June 25, 1946.
The XB-35 was powered by four Pratt & Whitney R-4360 turbo supercharged radial engines initially driving dual contra-rotating 3-blade propellers. Because of serious and continuing problems with the propeller gear boxes, the dual propeller arrangement was soon replaced by a single propeller. The 3-blade propeller was replaced by a 4-blade type that slightly increased the overall performance of the aircraft. Both XB-35s were scrapped in August 1949.
TECHNICAL NOTES: Armament: (Designed for) 20 .50-cal. plus 51,200 lbs. of bombs Engines: Four Pratt & Whitney R-4360 radials of 3,000 hp each (takeoff power) Maximum speed: 391 mph at 35,000 ft. Cruising speed: 183 mph Range: 8,150 miles with 16,000 lbs. bomb load Service ceiling: 39,700 ft. Span: 172 ft. 0 in. Length: 53 ft. 1 in. Height: 20 ft. 0 in. Weight: 180,000 lbs. (maximum gross weight) Crew: Nine (plus space for six relief crewmen) Serial numbers: 42-13603, 42-38323