Douglas C-1

The Douglas C-1 was a cargo and transport aircraft produced by the Douglas Aircraft Corporation for the United States Army Air Service starting in 1925. Douglas received an order for nine single-engined transports that year, the first flying from the Santa Monica, California factory on 2 May 1925, and the C-1 was the first aircraft assigned to the new C- category. Its design was based on several earlier Douglas designs, including the World Cruisers used in the 1924 round-the-world flight. The biplane was powered by a Liberty engine and carried a crew of two in an open cockpit, with an enclosed compartment for passengers or cargo. Seventeen larger C-1C aircraft were ordered in 1926 and 1927, and several C-1s served as engine testbeds, an air ambulance prototype and tankers in early air-to-air refueling experiments, including the 1929 record endurance flight of the Fokker C-2 Question Mark.