Cooper T51
The Cooper T51 was a Formula One and Formula Two racing car designed by Owen Maddock and built by the Cooper Car Company for the 1959 Formula One season. The T51 earned a significant place in motor racing history when Jack Brabham drove the car to become the first driver to win the championship with a rear-engined car, in 1959. The T51 was raced in several configurations by various entrants until 1963 and in all no less than 38 drivers were entered to drive T51s in Grand Prix races.
Aesthetically and aerodynamically the T51 was a natural development of the T43 and T45 cars that had given Cooper their first two wins. The Coopers continued their practice of building spaceframe chassis that ignored orthodox design thinking in having several curved links and the rear-engine layout meant weight savings and aerodynamic advantages over the front-engined cars, which typically had separate gearbox and differential cases, and had to find room for propshafts to the rear wheels. Also the location of the fuel tanks on either side of the cockpit rather than at the rear meant the car handled more consistently with different fuel loads, a vital factor during races which lasted up to three hours. One notable throwback, however, was the car's leaf spring rear suspension, although it used a more modern coil spring and wishbone setup at the front.
The standard F1 T51 was the first Cooper powered by the 2.5-litre 4-cylinder engine which Cooper and Lotus had commissioned Coventry Climax to build specifically for their rear-engined machines. The pioneering nature of this configuration created problems of its own, since there were so few rear-engined production cars from which a gearbox could be sourced. This shortage eventually created a niche in the market which paved the way for Hewland's prominence, but in the meantime many different solutions were tried, with varying degrees of success. The works Coopers were fitted with modified Citroen gearboxes, while Rob Walker's team ran bespoke units from Italian specialist Valerio Colotti, although these proved much more fragile.
...
Wikipedia