Niki Lauda won the 1978 Swedish Grand Prix at Anderstorp on June 17 in the Brabham BT46B, a Formula 1 car with a large fan at its tail. It never started another world championship race. Brabham withdrew it after that weekend, and the win stood.

That gives the fan car an odd place in the record books. It won every Grand Prix it started, even though that was just one. Its rivals were unhappy about it, and the reasons it went away had as much to do with the sport’s politics as with its rulebook.

Here is what the fan did, how Lauda won with it, and why Brabham parked the car after a single race.

Why Brabham wanted a radical answer

In 1978, Lotus had the car to beat. Colin Chapman’s Lotus 79 used aerodynamics as a performance aid, and for much of the year it was “borderline untouchable,” according to Motor Sport’s account of the race. Brabham needed something radical to answer it.

Gordon Murray, Brabham’s designer, came up with the BT46B. It was a “cut and shut job” adapted from the existing BT46, The Race reports. Power came from an Alfa Romeo flat-12 engine.

Brabham first tried the idea on BT46/2, an earlier test car. Then, for Sweden, the team converted BT46/6 for Lauda and BT46/4 for his teammate John Watson in the same way, according to Motor Sport’s 2025 profile of the car.

How the Brabham BT46B fan worked

The fan had no motor of its own. Instead, a linkage with four clutches tied it to the lower gearbox shaft, so the engine drove it. About 30 bhp went to the fan, The Race says.

Brabham said the fan’s main job was cooling. It pulled air out from around the engine and gearbox, so cooling air flowed down through a flat radiator, Motor Sport explains. At the same time, flexible skirts sealed off the underside of the car. As a result, the fan’s suction also created low pressure under the chassis, and with it downforce.

That distinction mattered. The rules banned moveable aerodynamic devices unless their primary purpose was something else. Measurements by the Commission Sportive Internationale (CSI) found that more than 55% of the fan’s power went to cooling, according to The Race. That finding was the basis for the car’s legality.

Protests before the race

Rival teams did not accept the cooling argument. Lotus, McLaren, Tyrrell, Surtees and Williams argued that the fan changed the car’s aerodynamics, so it had to stay fixed while the car was moving. The Swedish organizers received five official protests before the race, rejected them, and let the Brabhams start, Motor Sport reports.

The CSI also looked at the skirts. It ruled that they were fixed to the sprung part of the bodywork, which met the rules. In fact, The Race says the CSI found the car legal before the race and again after the protests.

Lauda’s win at Anderstorp

Mario Andretti took pole for Lotus with a lap of 1:22.058. The two Brabhams of Watson and Lauda lined up behind him, and Motor Sport suggests they had been “sandbagging” in qualifying.

Andretti led at the start, with Lauda second. Watson’s race ended early, and the official result shows him out after 19 laps. Lauda, meanwhile, pressed the Lotus and took the lead on lap 38, according to Motor Sport’s 2025 profile. Andretti’s Cosworth DFV failed eight laps later.

The official Formula 1 result has Lauda winning over 70 laps in 1:41:00.606. Riccardo Patrese finished second for Arrows, 34.019 seconds back. Ronnie Peterson’s Lotus took third, 34.105 seconds behind, and Lauda collected nine points.

Withdrawn, not banned

After the race, Brabham “voluntarily withdrew” the BT46B, Motor Sport says, and the magazine asks whether that was “benevolence or politics.” Formula 1’s own history says team owner Bernie Ecclestone made the call after rivals objected.

Ecclestone also headed the Formula One Constructors’ Association, known as FOCA. According to The Race, the car was not strictly banned. Instead, Ecclestone was persuaded to drop it, because heavy defeats for his rivals could raise costs for the group. The car stayed legal for the rest of 1978, and the wording of the rules changed for 1979.

So the Brabham BT46B’s official record is one start and one win: Niki Lauda, Anderstorp, June 17, 1978.

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This article was created with the help of AI and was reviewed and edited by Fast Lane Only editors before publication.