Armstrong Whitworth Apollo Armstrong Whitworth Apollo The Armstrong Whitworth AW.55 Apollo was a 1940s British four-engine turboprop airliner built by Armstrong Whitworth at Baginton. The aircraft was in competition with the Vickers Viscount but was beset with engine problems and only two were built. The requirement resulted from the Brabazon Committee's Type II design, calling for a small, medium-range pressurized aircraft to fly its less-travelled routes which became Air Ministry Specification C.16/46 for an aircraft able to carry 24-30 passengers over 1,000 mi (1,610 km) at a cruising speed of . The resulting design was the AW.55 Apollo, a low-wing cantilever monoplane with
Turboprop civilian aviation is in small commuter aircraft, where their greater power and reliability offsets their higher initial cost and fuel consumption. Turboprop-powered aircraft have become popular for bush airplanes such as the Cessna Caravan and Quest Kodiak as jet fuel is easier to obtain in remote areas than avgas. Due to the high price of turboprop engines, they are mostly used where high-performance short-takeoff and landing (STOL) capability and efficiency at modest flight speeds are required. Turboprop engines are generally used on small subsonic aircraft, but the Tupolev Tu-114 can reach 470 kt (870 km/h, 541 mph). Large military and