The Brabham BT49 is a Formula One racing car designed by South African Gordon Murray for the British Brabham team. The BT49 competed in the to Formula One World Championships and was used by Brazilian driver Nelson Piquet to win his first World Championship in .
The car was initially designed in 1979 as a short notice replacement for the team's Alfa Romeo-engined BT48, after Brabham team owner Bernie Ecclestone decided to end his relationship with the Italian engine manufacturer. The BT49 was created in only six weeks using elements of the BT48 chassis together with the widely used Cosworth DFV engine. The monocoque chassis is made from aluminium alloy and carbon fibre composites. The car was fitted with controversial hydropneumatic suspension and water-cooled brakes at different points in its life.
The BT49 was updated over four seasons taking a total of seven wins, six poles and 135 points. Seventeen were eventually built, most of which survive today. Some are used successfully in historic motorsport; Christian Glaesel won the 2005 FIA Historic Formula One Championship driving a BT49D.
Concept
The BT49 was created by South African designer Gordon Murray for the Brabham team during the 1979 season of the Formula One motor racing World Championship. The Brabham team had been competing in partnership with engine supplier Alfa Romeo since 1976 and won races in the 1978 season. However, the team's 1979 car, the BT48, was not a great success. Alfa Romeo entered their own Type 177 and Type 179 cars in Formula One Grands Prix that summer, helping to convince the Brabham team owner Bernie Ecclestone that the partnership was over. Motorsport author Alan Henry writes that Ecclestone did not want his team to take second place to an Alfa Romeo works team, and that the team designing Alfa Romeo's cars was drawing on Brabham knowledge.
Alfa's engines were powerful, but had proved troublesome and according to Henry, "the days during which pure power was the main criterion had temporarily vanished by the start of 1979". Instead aerodynamic ground effect, as brought to Formula One by the Lotus 78 two years earlier, was the most important factor. To allow them to focus on this, the Brabham team reverted to a known quantity, the reliable and widely used Ford Cosworth DFV engine that it had last used in 1975. Three BT49s were designed and built in only six weeks for the Canadian Grand Prix on 30 September 1979; two of them were converted BT48 chassis and one was newly built.
Chassis and suspension
Like all of its Formula One contemporaries, the BT49 chassis is a monocoque structure. It is built from sheet aluminium alloy with reinforcement from carbon fibre composite panels and is one of the first Formula One chassis to incorporate this material structurally. The chassis is slightly longer than that of the BT48, and is new from the cockpit back with revised sidepods and a structural fuel tank reduced from capacity to match the reduced fuel consumption requirements of the DFV compared to the Alfa Romeo. This allowed a reduction in dry weight over the BT48 of and of when fully fuelled.
The underside of the BT49 is shaped to create downforce through ground effect: air is accelerated under the car, reducing the air pressure beneath it and pushing the tyres down harder onto the track. This provides more grip and thus higher cornering speeds, but compared to conventional wings creates less of the drag that slows the car in a straight line. In its original form, the reduced pressure area under the car was sealed off with sliding skirts which rose and fell with the movement of the car to ensure no air could leak under it. According to Murray, the aerodynamics were the car's great strength: "It had more [downforce] than any other car and it all came from the ground effect. We ran the car with no front wing at all and scarcely any at the back."