On 30 October 1941, the preliminary order for development of the B-35 Flying Wing bomber was confirmed, including engineering, testing, and - most importantly - a 60 ft (18 m) wingspan, one-third scale aircraft, designated N-9M.[3] It was to be used in gathering data on flight performance and for familiarizing pilots with the program's radical, all-wing design. The first N-9M was ordered in the original contract, but this was later expanded to three test aircraft in early 1943. A fourth was ordered a few months later and would incorporate flight test improvements, including different, more powerful engines. They were designated N-9M-1, -2, -A, and -B, respectively.
The N-9M framework was partially constructed of wood to reduce its overall weight. The wings' outer surfaces were also skinned in a strong laminated plywood. The central section (roughly equivalent to the fuselage) was made of tubular steel. The aircraft were originally powered by two Menasco C6S-1 inverted air-cooled straight-six engines, driving twin-bladed propellers. The original engines were 290 hp (216 ); the N-9MB later upgraded to 400 hp (298 kW) Franklin engines
characteristics
Crew: 1
Capacity: 1 observer (N9MB)
Length: 17 ft 9 in (5.4 m)
Wingspan: 60 ft 0 in (18.3 m)
Height: 6 ft 7 in (2 m)
Wing area: 490 sq ft (45.5 m2)
Airfoil: NACA 65-019
Empty weight: 5,893 lb (2,673 kg)
Gross weight: 13,946 lb (6,326 kg)
Powerplant: 2 × Menasco C6S-4 , 275 hp (205 kW) each (N-9MB) 2x Franklin XO-540-7, 260 hp each
Performance
Maximum speed: 258 mph (415 km/h; 224 kn)
Range: 500 mi (434 nmi; 805 km)
Service ceiling: 21,500 ft (6,553 m)
