Flying Wing Prototype Aircraft
The Northrop N-9M flying wing prototype proved critical to the development of the XB-35 flying wing program that followed.
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Before the famous Northrop B-2 "Spirit" stealth bomber became a reality, Jack Northrop persevered in bringing a viable military-minded flying wing design into existence. From the twin-tail X-216H came the tail-less N-1M of 1941 which proved many qualities of the Northrop vision sound. Having sold the United States Army Air Force (USAAF) on the idea of a flying wing strategic bomber (to become the prop-powered "YB-35"), Northrop moved on producing a 1/3 scale prototype of this aircraft to represent the finalized product and work out any potential issues all the while collecting much needed flight data in the process. This endeavor then became the "N-9M" which appeared in 1942 and four examples were eventually built.
The contract for development of the full-scale YB-35 bomber came about in October of 1941, months ahead of the American entry into World War 2 (1939-1945). The N-9M emerged as a critical tool in understanding the various effects of tail-less aircraft flight as well as management of large surface area controlling and handling. The prospect of a flying wing was an exciting one, promising natural lifting tendencies, a shallower profile, and increased internal volume for fuel and weapons. The initial aircraft, N-9M-1, was lost to a crash on May 19th, 1943 (sadly fatal for the test pilot at the controls). The N-9M-2 and N-9M-A then followed, culminating in the final prototype vehicle - the N-9M-B - which benefited from lessons learned in the previous three airframes.
As built, the N-9M series mimicked much of what was already seen in the preceding N-1M research aircraft. The flying wing took on a boomerang-type, top-down profile with the cockpit centrally placed within the thickest part of the wing. While sitting under a largely unobstructed canopy, the pilot had to content with the massive wing surface area restricting vision out of the cockpit. The engines were buried within the design with drive shafts emanating from the upper surface and driving two-bladed propeller assemblies in a "pusher" arrangement. Since the N-9M lacked vertical fins, control surfaces were worked into the flying wing's trailing edges. The undercarriage was fully retractable, giving the aircraft a very pleasing and streamlined shape.
Crew accommodations amounted to one pilot. Overall length measured 17 feet, 9 inches with a wingspan reaching 60 feet and a height of 6 feet, 7 inches. Gross weight totaled 14,000lbs. Power was supplied from 2 x Menasco C6S-4 Buccaneer inverted 6-cylinder, air-cooled, in-line piston engines developing 275 horsepower each. Maximum speed was 260 miles per hour with a range out to 500 miles. Its service ceiling reached 21,500 feet.
The N-9M test vehicle first achieved flight on December 27th, 1942 and a further 45 flights then followed. However, many proved maddening affairs due to the temperamental technology and mechanics involved, particularly in the choice of powerplant. The aforementioned "N-9M-B" test vehicle then emerged with 2 x Franklin XO-540-7 series engines now developing 300 horsepower as a result.
With the end of World War 2 in 1945, many programs initially backed with great interest by the U.S. military were either curtailed or given up for good. The USAF cancelled the YB-35 initiative during 1949 after prototypes and pre-production systems were already in play. The N-9M had now seen its best days behind it and all but one (prototype N-9M-B) were scrapped.
Suffering from neglect for years in the California climate, N-9MB was eventually restored to flying condition and remains a salvaged piece of aviation history today. Despite the loss of the potential YB-35 strategic bomber contract, the USAF commissioned Northrop for a revised jet-powered form, this becoming the "YB-49". However, these only ever existed in prototype forms themselves but went on to heavily influence the B-2 bomber program some decades later - Northrop's flying wing military bomber finally realized.