The Northrop N-9M was an approximately one-third scale, span all-wing aircraft used for the development of the full size, 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 X-216H monoplane, and a decade later, the dual-propeller 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 1989 in US Air Force inventory. Design and development 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 Menasco C6S-1 "Buccaneer" inverted air-cooled straight-six engines, driving twin-bladed propellers, except for the N-9MB which was powered by two Franklin XO-540-7 engines. Operational history The first flight of the N-9M occurred on 27 December 1942 with Northrop test pilot John Myers at the controls. During the next five months, 45 flights were made. Nearly all were terminated by various mechanical failures, the Menasco engines being the primary source of the problems. After roughly 22.5 hours of accumulated flight time, the first N-9M crashed approximately 12 miles (19 km) west of Muroc Army Air Base (now Edwards Air Force Base) on 19 May 1943. The pilot, Max Constant, was killed as he attempted to recover the aircraft from a