N-9M | |
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The restored N-9MB Flying Wing at the Planes of Fame Air Museum | |
Role | Prototype |
Manufacturer | Northrop Corporation |
Designer | Jack Northrop |
First flight | 27 December 1942 |
Status | Prototype only |
Primary user | United States Air Force |
Number built | 4 |
The Northrop N-9M was an approximately one-third scale, 60-ft span all-wing aircraft used for the development of the full size, 172-ft wingspan Northrop XB-35 and YB-35 flying wing long-range, heavy bomber. First flown in 1942, the N-9M (M for Model) was the third in a lineage of all-wing Northrop aircraft designs that began in 1929 when Jack Northrop succeeded in early experiments with his single pusher propeller, twin-tailed, twin-boom, all stressed metal skin Northrop Flying Wing X-216H monoplane, and a decade later, the dual-prop N-1M of 1939–1941. Northrop's pioneering all-wing aircraft would lead Northrop-Grumman many years later to eventually develop the advanced B-2 Spirit stealth bomber, which debuted in Air Force inventory in 1989.
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. 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 after a crash of the first N-9M destroyed that airframe; this fourth N-9M incorporated various flight test-derived improvements and upgrades, including different, more powerful engines. The four aircraft 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 with a strong, specially laminated plywood. The central section (roughly equivalent to the fuselage) was made of welded tubular steel. The aircraft were originally powered by two 290 hp (216 kW) Menasco C6S-1 inverted air-cooled straight-six engines, driving twin-bladed propellers, except for the N-9MB which was powered by 2x 300 hp (224 kW) Franklin XO-540-7 engines.