North American NA-40

The North American NA-40 was a twin-engined prototype attack bomber that North American Aviation built in the late 1930s to answer a 1938 United States Army Air Corps circular asking for a new bomber that could carry a 1,200 lb payload 1,200 miles at more than 200 mph. The single aircraft first flew at the end of January 1939 with Pratt & Whitney radial engines, proved underpowered and unstable, and was rebuilt as the NA-40B with 1,600 hp Wright Twin Cyclone radials. It failed to win Army orders against rival designs, had been meant partly as an attack bomber for export to Britain and France, and was destroyed in a crash during testing, after which the Army ordered the Douglas DB-7 as the A-20 Havoc. Its lessons led directly to the NA-62, which went into production as the B-25 Mitchell.