Formula Three, also called Formula 3, abbreviated as F3, is a third-tier class of open-wheel formula racing. The various championships held in Europe, Australia, South America and Asia form an important step for many prospective Formula One drivers. Formula Three (adopted by the FIA in 1950) evolved from postwar auto racing, with lightweight tube-frame chassis powered by 500 cc motorcycle engines (notably Nortons and JAP speedway). The 500 cc formula originally evolved in 1946 from low-cost "special" racing organised by enthusiasts in Bristol, England, just before the Second World War; British motorsport after the war picked up slowly, partly due to petrol rationing which continued for a number of years and home-built 500 cc cars engines were intended to be accessible to the "impecunious enthusiast". The second post-war motor race in Britain was organised by the VSCC in July 1947 at RAF Gransden Lodge, 500cc cars being the only post-war class to run that day. Three of the seven entrants were non-starters, and, of the four runners, all but one retired on the first lap, leaving Eric Brandon in his Cooper Prototype (T2) trailing round to a virtual walk-over at an average speed of , though his best lap (which was the fastest recorded for any 500) was . Cooper came to dominate the formula with mass-produced cars, and the income this generated enabled the company to develop into the senior categories. Other notable marques included Kieft, JBS and Emeryson in England, and Effyh, Monopoletta and Scampolo in Europe. John Cooper, along with most other 500 builders, decided to place the engine in the middle of the car, driving the rear wheels. This was mostly due to the practical limitations imposed by chain drive but it gave these cars exceptionally good handling characteristics which eventually led to the mid-engined revolution in single-seater racing. Image:Monopoletta BMW, Bj 1949, Foto 1978.jpg|'''1949''': Monopoletta-BMW File:Cooper- Norton.jpg|'''1950''': Cooper Formula 500, Independent Rear Suspension, Norton Manx engine behind the driver.