Vickers Viscount Vickers Viscount The Vickers Viscount was a British medium-range turboprop airliner first flown in 1948 by Vickers-Armstrongs. A design requirement from the Brabazon Committee, it entered service in 1953 and was the first turboprop-powered airliner. The Viscount was well received by the public for its cabin conditions, which included pressurisation, reductions in vibration and noise, and panoramic windows. It became one of the most successful and profitable of the first post-war transport aircraft; 445 Viscounts were built for a range of international customers, including in North America. The Viscount was a response to the Brabazon Committee's Type II design for
Turboprop Kaman's K-125 synchropter, which used a Boeing T50 turboshaft engine to power it on 11 December 1951. Compared to turbofans, turboprops are most efficient at flight speeds below 725 km/h (450 mph; 390 knots) because the jet velocity of the propeller (and exhaust) is relatively low. Modern turboprop airliners operate at nearly the same speed as small regional jet airliners but burn two-thirds of the fuel per passenger. However, compared to a turbojet (which can fly at high altitude for enhanced speed and fuel efficiency) a propeller aircraft has a lower ceiling. The most common application of turboprop engines in