The front-engined Formula Two Cooper Bristol model was introduced in 1952. Various iterations of this design were driven by a number of legendary drivers – among them Juan Manuel Fangio and Mike Hawthorn – and furthered the company's growing reputation by appearing in Grand Prix races, which at the time were run to F2 regulations. Until the company began building rear-engined sports cars in 1955, they really had not become aware of the benefits of having the engine behind the driver. Based on the 500-cc cars and powered by a modified Coventry Climax fire-pump engine, these cars were called "Bobtails". With the centre of gravity closer to the middle of the car, they found it was less liable to spins and much more effective at putting the power down to the road, so they decided to build a single-seater version and began entering it in Formula 2 races.