The Douglas C-39 was a military transport aircraft that combined the fuselage and outer wings of the DC-2 with the centre wing section, engine nacelles and larger tail of the DC-3. The larger tail had first been used on the single C-38, and it cured the instability that had been the one of the few flaws of the DC-2/ C-33, although it isn’t entirely clear why the C-39 was ordered instead of a transport plane based on the DC-3.
Like the C-33 the C-39 had a large cargo door on the port side of the fuselage. It was powered by two 975hp Wright Cyclone engines, which increased its cargo capacity from 2,400lb to 3,600lb. Thirty five C-39s were built for the Army Air Corps in 1938-39. When the last C-39 was delivered in September 1939, it was the last version of the DC-2 to be completed (the C-41 and C-42 staff transports may have had higher type numbers, but they were actually produced in the middle of the C-39 production run).
Engines: Wright R-1820-55 Cyclone x2
Power: 975hp each
Wing span: 85ft 0in
Length: 61ft 6in
Height: 18ft 8in
Empty weight: 14,287lb
Loaded weight: 21,000lb
Maximum speed: 210mph at 5,000ft
Cruising speed: 156mph at 5,000ft
Service ceiling: 20,600ft
Normal range: 1,170 miles
Maximum range: 1,600 miles
Cargo payload: 3,600lb