Hawker Siddeley HS 748 Paper ended most military manned-aircraft development in the UK, and Avro decided to re-enter the civilian market. The Vickers Viscount had the larger end of the short-haul market, and Avro therefore decided to design a smaller regional airliner powered by two Rolls-Royce Dart turboprop engines, intended to replace the many DC-3 Dakotas that were by then reaching the end of their economic lifespan. Original plans were for a 20–30 seat aircraft with a similar configuration to the Fokker F27, but talks with potential customers soon led to a low-wing 40-seat design being chosen for the 748 project. Avro was not
Vickers machine gun Vickers E.F.B.1 biplane, which was probably the world's first purpose-built combat aeroplane. However, by the time the production version, the Vickers F.B.5, had entered service the following year, the armament had been changed to a Lewis gun. During World War I, the Vickers gun became a standard weapon on British and French military aircraft, especially after 1916. Although heavier than the Lewis, its closed bolt firing cycle made it much easier to synchronize to allow it to fire through aircraft propellers. The belt feed was enclosed right up to the gun's feed-way to inhibit effects from wind. Steel disintegrating-link ammunition