Turboprop on 20 September 1945. From their experience with the Trent, Rolls-Royce developed the Rolls-Royce Clyde, the first turboprop engine to be fully type certificated for military and civil use, and the Dart, which became one of the most reliable turboprop engines ever built. Dart production continued for more than fifty years. The Dart-powered Vickers Viscount was the first turboprop aircraft of any kind to go into production and sold in large numbers. It was also the first four-engined turboprop. Its first flight was on 16 July 1948. The world's first single engined turboprop aircraft was the Armstrong Siddeley Mamba-powered Boulton
Vickers Viscount a post-war small medium-range pressurised aircraft to fly less-travelled routes, carrying 24 passengers up to 1,750 mi (2,816 km) at 200 mph (320 km/h). During discussions between the committee and Vickers' chief designer, Rex Pierson, Vickers advocated turboprop power. The committee was not convinced and split the specification into two types, the Type IIA using piston power, which led to the Airspeed Ambassador, and the turboprop-powered Type IIB which Vickers was selected to develop in April 1945. British European Airways (BEA) was involved in the design and asked that the aircraft carry 32 passengers instead, but remained otherwise similar. The