History
The North American XB-28 was initially developed for the US Army Air Corps requirement, which called for a fast medium bomber with high-altitude capabilities and to fulfill a replacement for North American’s own B-25 Mitchell. Before the first flight of the B-25 Mitchell occurred, the USAAC presented specifications for a high-altitude medium bomber to be powered with two turbo-supercharged engines and equipped with cabin pressurization. The North American proposed its NA-63 (XB-28) design of a two-engined medium bomber, while the Martin company submitted its Model 182 (XB-27) design.
The Martin proposal was dropped, and the North American proposal was more favorable. Therefore, on February 13, 1940, the USAAC ordered a prototype of the NA-63, which became the XB-28 in its military designation. The XB-28 aircraft was based on the overall B-25 configuration; however, it evolved as a new design and externally reassembled Martin B-26 Marauder. The design incorporated a glazed-over nose section, a stepped cockpit, a tricycle undercarriage, high-mounted wings, and a twin-engine configuration. It used a single vertical instead of Mitchell’s distinctive twin tail. It was powered by a pair of turbo-supercharged Pratt & Whitney R-2800-11 engines, rated at 2,000 horsepower each for takeoff.
The XB-28 was one of the first military aircraft to incorporate a pressurized cabin. It had three remotely-controlled turrets on the upper, lower, and tail, with two 0.50-cal. machine guns each. Pericope sights were used to control these guns since cabin pressurization was used in the aircraft. The gunners operated with their periscope sight in seats behind the pilots. The bomber was cleared to carry up to 4,000 pounds of bombs.
On April 26, 1942, the first prototype (40-3056) was rolled out and flew for the first time, only eight days after the North American B-25s were involved in the Doolittle Raid over Tokyo, Japan. The flight testing was very successful for the XB-28, and its high-altitude performance exceeded that of the B-25 and B-26 bombers. XB-28 flew much faster, by about 70 mph, than the B-25B Mitchell and could cruise better at a much higher altitude of up to 34,800 feet, thanks to its extra power and cabin pressurization. The XB-28 had proved its exceptional results and passed the USAAC initial requirements.
However, as the US entered the war, the USAAC was transformed into the US Army Air Forces (USAAF). The USAAF was highly engaged on all fronts. This resulted in evolving their air doctrine and changing requirements based on their combat experience with B-25 and B-26 bombers, mostly during low/medium-altitude bombing.
Although the XB-28 at low and medium altitudes could offer a performance advantage over the B-25 and B-26 aircraft, the USAAF decided not to proceed with the XB-28 and not disturb the North American Mitchell production. In addition, the USAAF decided that heavy bombers such as the B-29 Superfortress were best left to do the high-altitude bombing operations alone, and the USAAF saw no need for replacement for the B-25 and potentially B-26 bombers since they were already excelling at low/medium-altitude bombing operations.
After deciding they didn’t need the XB-28 for the medium bomber role, the USAAF was still interested in ordering a development of the high-speed, high-altitude reconnaissance aircraft, the XB-28A. It was powered by another version of the R-2800-27 engines. It had all turret guns omitted. This second prototype was lost in a crash into the Pacific Ocean off Southern California on August 4, 1943, with its crew safely bailed out.
The surviving XB-28 aircraft was scrapped afterward, and the name “Dragon” used for the bomber was not official in this era.
