The Douglas B-18, which had been designed to meet a US Army Air Corps requirement of 1934 for a high-performance medium bomber, was clearly not in the same league as the Boeing B-17 Flying Fortress, which had been built to the same specification. Figures highlight the facts: 350 B-18s were procured in total, by comparison with almost 13,000 B-17s. In an attempt to rectify the shortcomings of their DB-1 design, Douglas developed in 1938 an improved version and the proposal seemed sufficiently attractive for the US Army to award a contract for 38 of these aircraft under the designation B-23 and with the name Dragon.
Although the overall configuration was similar to that of the earlier aircraft, when examined in detail it was seen to be virtually a new design. Wing span was increased, the fuselage was entirely different and of much improved aerodynamic form, and the tail unit had a much higher vertical fin and rudder. Landing gear was the same retractable tailwheel type, but the engine nacelles had been extended so that when the main units were lowered in flight they were faired by the nacelle extensions and created far less drag. Greatly improved performance was expected from these refinements, plus the provision of 60 per cent more power by the use of two Wright R-2600-3 Cyclone 14 engines. An innovation was the provision of a tail gun position, this being the first US bomber to introduce such a feature.
First flown on 27 July 1939, the B-23s were all delivered to the US Army during that year. Early evaluation had shown that performance and flight characteristics were disappointing. Furthermore, information received from the European theatre during 1940 made it clear that development would be unlikely to result in range, bombload and armament capabilities to compare with the bomber aircraft then in service with the combatant nations, or already beginning to emerge in the USA. As a result these aircraft saw only limited service in a patrol capacity along the US Pacific coastline before being relegated to training duties. During 1942 about 15 of these aircraft were converted to serve as utility transports under the designation UC-67, and some of the remainder were used for a variety of purposes including engine testbeds, glider towing experiments and weapons evaluation.
Following the end of World War II many surplus B-23s and UC-67s were acquired by civil operators for conversion as corporate aircraft. The majority were modified by Pan American's Engineering Department, equipped to accommodate a crew of two and passengers. Some of them remained in civil use for about 30 years.
