Douglas DC-1
The Douglas DC-1 was the first model of the famous American DC (Douglas Commercial) commercial transport aircraft series. Although only one example of the DC-1 was produced, the design was the basis for the DC-2 and DC-3, the latter being one of the most successful aircraft in the history of aviation. Design and development Development of the DC-1 can be traced back to the 1931 crash of a TWA airliner, a Fokker F-10 trimotor in which a wing failed, probably because water had seeped between the layers of the wood laminate and dissolved the glue holding the layers together. Following the accident, the Aeronautics Branch of the U.S. Department of Commerce placed stringent restrictions on the use of wooden wings on passenger airliners. Boeing developed an answer, the 247, a twin-engined all-metal monoplane with a retractable undercarriage, but their production capacity was reserved to meet the needs of United Airlines, part of United Aircraft and Transport Corporation which also owned Boeing. TWA needed a similar aircraft to respond to competition from the Boeing 247 and they asked five manufacturers to bid for construction of a three-engined, 12-seat aircraft of all-metal construction, capable of flying 1,080 mi (1,740 km) at 150