The original design resulted from the Brabazon Committee's Type IIB design, calling for a smaller medium-range turboprop-powered pressurized aircraft to fly it's less-travelled routes, carrying 24 passengers up to 1,750 miles at 200mph. British European Airways (BEA) was involved in the design and asked that the plane carry 32 passengers instead, but remained otherwise similar. The Type IIA was to be a piston powered version of similar performance, and was built as the Airspeed Ambassador.
The resulting Vickers Type 630 design was completed in 1945, a thiry-two seat plane powered by four Rolls-Royce Dart engines for an improved cruising speed of 275mph. An order for two prototypes was placed in March 1946, and construction started almost immediately. Originally to be named Viceroy, the name had to be changed after the partition of India in 1947. There was some work on replacing the Darts with the Armstrong Siddeley Mamba, but this was dropped by the time the prototypes were reaching completion.
The prototype Model 630 flew on July 16, 1948, and the second prototype was built as a test bed with two Rolls-Royce Tay turbojets in place of the four Darts. The first prototype was awarded a restricted Certificate of Airworthiness on September 15th 1949, followed by a full Certificate on July 27th 1950, and placed into service with BEA the next day to familiarize the pilots and ground crew with the new aircraft. However the design was considered to small and slow (at 275mph), making the per-passenger operating costs too high for regular service.
The design then went back to the drawing board and re-emerged as the larger Type 700 with up to forty-eight passengers (53 in some configurations), and a cruising speed of 308mph. The new prototype first flew August 28, 1950. British European Airways ordered twenty V.701s, and soon orders came in from other airlines as well. The first 700 was delivered to BEA in January 1953, and in April began the world's first turboprop-powered service.
Three years later the Viscount won all honours in the transport section of the 12,367-mile air race from London to Christchurch, New Zealand. The plane averaged 320 miles per hour in the event, crossing the finishing line nine hours ahead of its closest rival. The Model 700D added more powerful engines, and the Model 724 included a new fuel system, two-pilot cockpit, and increased weights.
The final major change to the design was the Type 800 Super Viscount, stretched 3ft 10in for up to 71 passengers. A further change to the fuselage was planned, but later renamed as the Vanguard instead.
The type continued in BEA and British Airways service until the 1980s, eventually being passed on to charter operators such as British Air ferries (later British World). The last British owned Viscounts were sold in South Africa where a small number are still in use.
For Model 800:
For Model 800: