Enter the DC1

The handbuilt One and Only DC-1, first of the "Douglas Commercial" family shown here at Grand Central Air Terminal, Glendale, CA., was a low wing all metal monoplane which flew on July 1, 1933. Two Wright Cyclone 710 hp engines carried 14 passengers at 180 mph. Later it was enlarged and designated the great civilian DC-3 and the C-47 "Gooney Bird" for military service. Photo courtesy of Dan MacPherson.

Development of the DC-1 can be traced back to the 1931 crash of TWA Flight 599, which suffered a structural failure of one of its wings, probably due to water which had over time seeped between the layers of the wood laminate and dissolved the glue holding the layers together. Following the accident, the Aeronautics Branch of the US 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 that 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-engine, 12-seat aircraft of all-metal construction, capable of flying 1,080 mi (1,740 km) at 150 mph (242 km/h). The most demanding part of the specification was that the airliner would have to be capable of safely taking off from any airport on TWA's main routes (and in particular Albuquerque, at high altitude and with severe summer temperatures) with an engine failed.

Donald Douglas was initially reluctant to participate in the invitation from TWA's president, Jack Frye. He doubted there would be a market for 100 aircraft, the number of sales necessary to cover development costs. Nevertheless, he submitted a design consisting of an all-metal, low-wing, twin-engine aircraft seating 12 passengers, a crew of two and a flight attendant. The aircraft exceeded the specifications of TWA even with two engines. It was insulated against noise, heated, and fully capable of both flying and performing a controlled takeoff or landing on one engine.

Don Douglas stated in a 1935 article on the DC-2 that the first DC-1 cost $325,000 to design and build.

More DC1 facts and history here.