To speed the development of a pure jet bomber, the US Army Air Force contracted Douglas to produce two Douglas XB-43 bomber prototypes using the basic design of the XB-42. The proposed conversion replaced the XB-42's Allison piston engines with two turbojets. Changes included air inlets, incorporating two extended tail pipes to discharge the jet efflux at the tail, and replacing the cruciform tail unit with a conventional structure which had a fin and rudder of increased height and area by comparison with the XB-42.
The XB-42 static test airframe was modified to produce the first XB-43. With delays resulting from the war's end and the provision of the turbojet powerplant, eventually, the XB-43 was flown for the first time on 17 May 1946.
By that time, however, and despite the prototype's good overall performance, The USAAF was already looking to more-capable turbojet-powered bombers and this, the US Army Air Force's first jet-bomber, was used only for flight-test purposes. The second prototype was completed and delivered in May 1947, being used as an engine testbed before it was retired in late 1953.
Engines: 2 x General Electric J35-GI-3 turbojet, 16.7kN
Max take-off weight: 17932 kg / 39533 lb
Empty weight: 9877 kg / 21775 lb
Wingspan: 21.69 m / 71 ft 2 in
Length: 15.6 m / 51 ft 2 in
Height: 7.39 m / 24 ft 3 in
Wing area: 52.3 sq.m / 562.95 sq ft
Max. speed: 829 km/h / 515 mph
Cruise speed: 676 km/h / 420 mph
Ceiling: 11735 m / 38500 ft
Range: 1770 km / 1100 miles
Armament: 2 x 12.7mm rear-firing guns, 2722kg of bombs