North American NA-21 XB-21

08/31/2010. Remarks by Johan Visschedijk: "Design work on the first North American bomber began at Inglewood, California during 1935, construction started in January 1936 and the prototype emerged as a clean but somewhat portly mid-wing aeroplane in the same general category as the Douglas B-18, then already in production for the USAAC. Carrying the s/n 38-485, the aircraft made its first flight was made on December 22, 1936.

The NA-21 (sometimes referred to as Dragon) was an attempt to improve on the B-18's performance whilst using the same formula, and it was powered by two 1,200 hp Pratt & Whitney R-2180-1 Twin Hornet radial engines, fitted with F-10 turbo-superchargers.

With a crew of six, the all-metal NA-21 was relatively heavily armed, with single 0.30 in (7.62 mm) machine guns in each of five positions including a ball-type turret in the nose, a dorsal turret, two waist positions and a ventral position. A maximum bomb-load of 10,000 lb (4,536 kg) could be carried over 600 mi (966 km), or 2,200 lb (998 kg) for 1,960 mls (3,058 km).

After some changes, including a reduction in rudder area (administrated under the production number NA-39), the NA-21 was accepted for testing at Wright Field as the XB-21, but a planned order for five YB-21s was not confirmed and the XB-21 ended its life, with the nose and dorsal turrets removed, as a hack at Wright Field."