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
Regional airliner and British Aerospace ended production of their BAe Jetstream 41 after 100 delivered. By 2006 only the ATR 42/72 models and the Dash 8 remained in production. Turboprop airliner deliveries are correlated with oil prices with a lag of a few years. Another reason for the downturn in the turboprop market was the introduction of the first regional jets. Although a number of small jets entered service in the 1950s and 60s, notably the Sud Aviation Caravelle, Fokker F28 Fellowship and DC-9, these could not compete in terms of cost of operation with the turboprop designs, and were suitable for