Brabham BT46B

Brabham BT46B

by Luca Dal Monte

The completely revolutionary single-seater that Gordon Murray presented in the summer of 1977 undergoes significant changes to be able to take to the track in the world championship. The solutions that the ingenious South African designer has hypothesized are too advanced compared to current technology.

In three months, Murray redesigns the BT 46, modifying the entire rear part of the car with a fairing that continues laterally, completely wrapping around the engine bay thanks to movable side skirts. Thus, the BT 46B is born. But the ace up the sleeve is the huge extractor fan positioned under the rear wing.

The fan, placed above the gearbox, serves first and foremost to cool a new radiator positioned horizontally above the engine, but it ends up discharging the air from underneath the car and keeping it glued to the ground. When he first did the calculations, Murray had to redo them because he couldn’t believe how much downforce he could achieve with the fan – the number, he says, was “astronomical.”

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Niki Lauda: “Today the car worked really well,” says Lauda to the reporters besieging him after crossing the finish line first at Anderstorp. “I controlled Andretti well, and when I deemed it appropriate, I passed him. I had more acceleration and stability.” But when pressed to admit that Murray’s fan made the difference today, Niki sticks to Brabham’s official version: “That’s not relevant: it’s just a fan to cool the car better and extract air from the radiator.” Amid a sea of controversy, Niki’s victory in the 1978 Swedish Grand Prix is approved. But there will be no future for the fan.

John Watson: The fan brings less luck to the Northern Irish driver. Watson ignores it, but his BT 46B has been somewhat “sabotaged” by his own team. To prevent Watson from winning at Lauda’s expense, in agreement with Chiti, Ecclestone decided to intervene on BT 46 number 2 by having the Brabham mechanics drill holes in the fan blades. As a result, the fan on Watson’s car worked less effectively than on Lauda’s, and the Brit’s car only partially benefited from the ground effect that made Lauda’s car fly.

Our model cars:

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“All Gordon did was simply move the water and oil radiators back, mounting them above the engine, according to the regulations, and then mounted a large cooling fan behind them that sucks the air passing between them,” says driver John Watson. It’s Murray’s extraordinary response to Chapman’s ground effect, impossible to achieve on the Brabhams in the same way Chapman achieves it on the Lotuses due to the triangular configuration of the side pods of the BT 46B.

The solution works and leads to the first victory of the season. But the world of Formula 1 protests fiercely, and the fan will soon be forced to leave the scene.

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