The North American NA-40 was an American prototype bomber aircraft developed by North American Aviation in the late 1930s for evaluation by the United States Army Air Corps . Although unsuccessful, it led directly to the North American B-25 Mitchell medium bomber.
8-750: The Air Corps issued a circular (number 38-385) in March 1938 describing the performance they required from the next bombers — a payload of 1,200 lb (540 kg) with a range of 1,200 mi (1,900 km) at more than 200 mph (320 km/h). Several American aircraft companies responded with submissions: Bell Model 9 with two engines, Boeing-Stearman Model X-100 with Pratt & Whitney R-2180 radials, Douglas Model 7B with Pratt & Whitney R-1830 Twin Wasp radials, Martin Model 167F and North American submitted their NA-40 design. The NA-40 had benefited from
16-614: A fault with the aircraft design, the U.S. Army ordered the DB-7 as the A-20 Havoc . The Air Corps issued a specification for a medium bomber in March 1939 that was capable of carrying a payload of 2,400 lb (1,100 kg) over 1,200 miles (1,900 km) at 300 mph (480 km/h) NAA used the NA-40B design to develop the NA-62, which competed for the medium bomber contract. No YB-25
24-786: The North American XB-21 (NA-39) of 1936, which was the company's partly successful design for an earlier medium bomber that had been initially accepted and ordered, but then cancelled. However, the company's experience from the XB-21 contributed to the design and development of the NA-40. The single NA-40 built flew first at the end of January 1939. It went through several modifications to correct problems. These improvements included fitting 1,600 hp (1,193 kW) Wright R-2600 "Twin Cyclone" radial engines , in March 1939, which solved
32-641: The United Kingdom and France, both of which had a pressing requirement for such aircraft in the early stages of World War II. Despite the loss of the 7B in an accident injuring a French observer in January, the French had ordered the 7B and a revised version (as the DB-7). Unfortunately, the NA-40B was destroyed in a crash on 11 April 1939 while undergoing testing. Although the crash was not considered due to
40-621: The lack of power. In March 1939, North American delivered the substantially redesigned and improved NA-40 (as NA-40B) to the United States Army Air Corps for evaluation. It was in competition with other manufacturers' designs produced - the Bell had not been built - Douglas 7B, Stearman XA-21, and the Martin Model 167F but failed to win orders. The aircraft was originally intended to be an attack bomber for export to
48-490: The war years from the He 111P onwards, with a streamlined, well-framed greenhouse canopy enclosing both the pilot and bombardier stations. The XA-21 was first tested with the streamlined cockpit but this configuration was found to restrict the pilot's forward vision, and the aircraft was rebuilt with a conventional (stepped) nose and cockpit structure. Although this change in the cockpit did not significantly affect performance,
56-696: Was a competitor in a United States Army Air Corps competition for a twin-engined attack aircraft which (after redesigns) led to the Douglas A-20 Havoc , Martin A-22 Maryland and North American B-25 Mitchell . The X-100, designated XA-21 following purchase by the Army Air Corps, was a twin-engined high-winged monoplane of all-metal construction. Its initial design featured an unusual " stepless cockpit " arrangement, much like those on most German World War II bombers designed during
64-655: Was available for prototype service tests. In September 1939, the Air Corps ordered the NA-62 into production as the B-25, along with the other new Air Corps medium bomber, the Martin B-26 Marauder "off the drawing board". Data from Baugher General characteristics Performance Armament Related development Aircraft of comparable role, configuration, and era Related lists Stearman XA-21 The Stearman XA-21 ( Model X-100 )
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