Northrop N-9M - WikiHQ

The Northrop N-9M was an approximately one-third scale, span flying 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

left|thumb|Northrop N9M-2 in the NACA [[Ames Research Center wind tunnel]]

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.

thumb|The N-9MA in flight later in the test program with the upper surface painted blue

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. 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 right-hand, 60° nose-down spin. The investigation found that Constant had suffered control reversal, the control column had been pressed against his chest during his recovery attempt from the steep spin, preventing him from parachuting to safety. Actions were taken to fix this problem and prevent it from happening on other N-9M test aircraft. From 1993, the yellow-and-blue Flying Wing was exhibited, with flight demonstrations at several airshows every year.

In April 2006, the N-9MB suffered an in-flight engine fire. The aircraft was landed safely with limited damage. Donations to the museum were solicited for its repair, and the aircraft was fully repaired to flight status. It was flown again during the annual Chino airshow on 15–16 May 2010. The pilot was killed but no ground casualties were reported. The National Transportation Safety Board attributed the crash to the "pilot's loss of control for undetermined reasons", stating that "given the significant fragmentation of the wreckage, the reason for the loss of control could not be determined".

Shortly after take-off from Chino Airport, the aircraft crashed on the grounds of the California Rehabilitation Center, a state prison in Norco, at 12:10 pm local time.

The pilot and sole aircraft occupant was killed but no ground casualties were reported. The 51-year-old male pilot David Vopat was a certified flight instructor and held an airline transport pilot certificate. He held type ratings for various modern and historical aircraft, and had accrued 20,029 hours of total flight time, including 25 flight hours in the accident aircraft over a 4-year period. He was wearing a parachute during the accident flight.