The Brabham BT50 was a Formula One racing car designed by Gordon Murray and powered by a turbo BMW engine. It was raced by the Brabham team, owned by Bernie Ecclestone, during the 1982 Formula One season. Driven by Nelson Piquet and Riccardo Patrese, it made its debut at the South African Grand Prix before being withdrawn for further development of its engine while the team reverted to the previous year's car, the Brabham BT49. On the reintroduction of the BT50, Piquet finished fifth in the Belgian Grand Prix. A few races later he drove it to a win in the Canadian Grand Prix. Later in the year it achieved three more finishes in the points for the team. During the second half of the season, Brabham implemented the strategy of mid-race refueling. This allowed Piquet and Patrese to start the races relatively light and use their reduced weight to gain track position over their competitors before stopping to refuel. The poor reliability of the BT50 meant that they had only a few opportunities to demonstrate the strategy in practice.
Despite its unreliability, the BT50 was fast, taking one pole and three fastest laps during the season. Brabham finished fifth in the 1982 Constructor's Championship with 41 points although 19 of these were earned with the BT49.
Background
The possibility of BMW entering Formula One was raised as early as mid-1979. Brabham's lead driver, Niki Lauda, was becoming disgruntled at the performance of the uncompetitive Brabham-Alfa BT48 and discreet discussions were held with aim of getting him into a BMW-powered McLaren. The Brabham team management were also unhappy with Alfa Romeo, not helped by the Italian company producing its own car and entering it into that year's Belgian Grand Prix.
While the proposed Lauda-McLaren deal did not eventuate and the Austrian abruptly retired at the Canadian race, the relationship between Brabham and BMW had prospered and they came to an engine supply agreement in the summer of 1980. While Brabham switched to normally aspirated Cosworth DFVs for the 1980 season, the team's owner, Bernie Ecclestone, could see that turbo engines were likely to be key to being competitive in the long term.
Design and development
Initial testing of the BMW M12/13 turbo engine, a modification of the four-cylinder iron block and existing Formula Two four-valve cylinder head, began in late 1980 using a modified BT49 while Brabham's chief designer, Gordon Murray, worked on the BT50. The new car was completed in mid-1981 and carried over many elements from the BT49, which Brabham had run throughout the 1980 season. The BT50 had double wishbone suspension and pullrod activation coil spring/damper units, which were semi-inboard, while its monocoque was an aluminium tub with carbon stiffening panels. The team continued with its Hewland/Alfa gearbox, first used in 1976 when Brabham ran a V12 Alfa Romeo, but this was found to struggle with the power and torque of the BMW turbo engine.
The BT50 had a slightly longer wheelbase and a fuel cell with of capacity to accommodate the fuel consumption requirements of the engine. Overall, with the engine in place, the BT50 weighed in at , ten more than its predecessor. It was also one of the first Formula One cars to feature onboard telemetry as a means of monitoring the engine's fuel injection.
The first public appearance of the BT50 was at the 1981 British Grand Prix, where the team's lead driver, Nelson Piquet, used it in practice. He set a practice time 0.7 seconds slower than his qualifying effort in the Cosworth DFV-powered BT49. The BT50 handled poorly but still recorded through the speed trap, some faster than the BT49. Piquet, a firm advocate for the BMW engine and believing, like Ecclestone, that the road to success in the near future was with a turbocharged engine, tested the BT50 throughout 1981. Testing was plagued with unreliability; in one testing session at the Paul Ricard circuit in France, the team suffered nine engine blowups.
Once the 1982 season began, there was relatively little development of the BT50 chassis during the season although there were some aerodynamic revisions. A total of five BT50s were built.