The Douglas B-23 Dragon was produced in an attempt to replace the B-18 Bolo, but its performance wasn't as good as its more modern rivals and only 38 were ever built.
The Douglas B-18 had been selected for production ahead of the Boeing B-17, but by the late 1930s it was clear that the Douglas aircraft was obsolete. The first attempt to improve it was the XB-22, a project to power it with 1,600hp Wright R-2600-2 engines, but the estimated performance figures for this design weren't impressive and it was abandoned.
Douglas suggested a more radical solution. This would use the wings of the DC-3 and a new more streamlined fuselage, without the bulging 'belly' of the B-18. The Air Corps was suitably impressed with the new design, and ordered it straight into production. Thirty eight B-23s were ordered, replacing the same number of B-18As on Contract AC9977 (serial numbers 39-27 to 39-64). No prototype was ordered.
The B-23 had a smooth nose with a good bombardier's position, and a ball-mounted machine gun in place of the nose turret of the B-18. The B-23 was the first US bomber to carry a glazed tail gunner's position, built into the base of the rudder. This carried a hand-held 0.50in machine gun. Two 0.30in guns were carried in the fuselage - one firing down through a ventral hatch and one through hatches on the sides and top of the aircraft. The B-23 was powered by two 1,600hp Wright R-2600-3 Cyclone engines. It could carry 2,000lb of bombs internally and could also carry a camera on the left side of the fuselage.
The first aircraft was completed in July 1939 and the last in September 1940. Although it was an improvement on the B-18, it wasn't on a par with the B-17E Flying Fortress. It was also outclassed by the new medium bombers, in particular the North American B-25 Mitchell and the Martin B-26. It was quickly retired as a bomber, and instead used for a number of alternative purposes.
At least eighteen B-23s were converted into transport aircraft, as the UC-67. Other aircraft were used as test aircraft. One was used for experiments in picking up a glider while still in the air, using a hook that engaged with the glider's tow line. One was used to test remote controlled guns. One was used to test the 1,850hp Pratt & Whitney R-2800-5 engine. One was used as the control ship for Culver PQ-8 radio controlled targets.
After the war the surviving B-23s and UC-67s were sold off and most were converted into executive transports, with room for twelve passengers who were carried in some comfort. Some of these aircraft remained in use into the 1970s.
Engine: Two Wright R-2600-3 Cyclones
Power: 1,600hp each
Crew: 6 (pilot, bomber-aimer, navigator, radio operator, camera operator, tail gunner).
Length: 58ft 4in
Height: 18ft 6in
Empty weight: 19,059lb
Maximum take-off weight: 32,400lb
Max speed: 282mph
Cruising speed: 210mph
Climb Rate: 6.7min to 10,000ft
Service ceiling: 31,600ft
Range: 1,445 miles with 4,000lb of bombs
Maximum range: 2.750 miles
Armament: Four .30in machine guns
Bomb load: 2,000lb