The Douglas C-33 was the first purpose-built military transport aircraft to be based on the Douglas DC-2, and was thus the ancestor of the thousands of C-47s, C-53s and Dakotas that would be built during the Second World War.
A number of changes were made to turn the DC-2 airliner into a military transport aircraft. Military standard Wright R-1820-25 Cyclones enignes were installed. All of the comfortable fittings were removed. The internal floor was strengthened, allowing the C-33 to carry up to 2,400lb of cargo, or 12 fully equipped soldiers. The standard airline door at the back of the port side of the aircraft was replaced with a six foot wide, five foot high cargo door, which opened forward. The door was hinged in the middle, and so could be either half or fully opened. It was possible to mount a cargo hoist above the door, to speed the loading of heavier cargos.
Eighteen C-33s were built, and were given 1936 serial numbers. Production then moved on to the C-39, with more powerful engines, and which combined the DC-2 fuselage with the central wing section and larger tail of the DC-3.
Engines: Wright R-1820-25 Cyclone x2
Power: 750hp each
Wing span: 85ft 0in
Length: 61ft 11.75in
Height: 16ft 3.62in
Empty weight: 12,476lb
Loaded weight: 17,560lb
Maximum weight: 18,588lb
Maximum speed: 202mph at 2,500 feet
Cruising speed: 171mph
Service ceiling: 20,000ft
Normal range: 916 miles
Payload: Either 2,400lb of cargo or twelve passengers