Douglas DC-7

The Douglas DC-7 was the last major piston-engined passenger aircraft built by the Douglas Aircraft Company, produced from 1953 to 1958 as a derivative of the DC-6. American Airlines asked for an airliner that could fly coast to coast nonstop in about eight hours, and its president C. R. Smith ordered 25 at a total price of 40 million dollars, which covered Douglas development costs. The fuselage was 40 inches longer than the DC-6B and four Wright R-3350 Duplex-Cyclone Turbo-Compound engines provided the power. The prototype flew in May 1953, and the later DC-7B and DC-7C variants were also built in large numbers. Engine failures were frequent, and the jet-powered DC-8 followed within a few years. No DC-7 remained in service by 2020.