History Column: The Brabham fan car

The BT46B

The Brabham BT46B made its debut at the Swedish Grand Prix in Anderstorp in 1978. It won, but the supercar was withdrawn almost immediately. This is its unique one-race story.

The 1978 season was all about downforce. Colin Chapman’s Lotus 79, which debuted at the Belgian Grand Prix in Zolder, was set to take everything. The “wing car” with its skirts generated so much grip that the Lotus duo of Mario Andretti and Ronnie Peterson seemed to be untouchable.

Andretti won easily in Belgium and Spain, and it was obvious they would have an easy walk to the title. All chief designers worked flat out to catch up with the Lotus cars. The most significant result came from the drawing board of Brabham’s Gordon Murray. The BT46B had a huge fan at the back of the vehicle, which also resulted in this creature being referred to as the “fan car”.

John Watson, Brabham’s driver told the Paddock magazine: “I drove the initial version at a Brands Hatch test. From memory, the test was as much about systems as about the fan effect itself. There was a lot of in/out laps, but as we had no yard stick to judge the fan car with, we couldn’t draw any specific conclusion as to how much more competitive it was against the basic BT46 or the Lotus 79. BT46B’s true ground effect sees the downforce increase by the square of the speed, that is, the faster you go, the more grip you get”.

The team owner Bernie Ecclestone knew that several teams would protest heavily against the BT46B.

The team’s Niki Lauda put it in his usual simple way: “Murray designed and developed the car, and as they showed it to me, I said that they were absolutely nuts! We went to Brands Hatch, but the car understeered like hell; three laps, it didn’t work at all. I told them, guys, one gear lower, more throttle. And we adjusted the wings. Suddenly, the car worked, it was just sucked into the ground”.

The team owner Bernie Ecclestone knew that several teams would protest heavily against the BT46B. John Watson continues: “In Sweden, it became clear that the circuit suited the fan car perfectly; the nature of the corners were working in its favour. There was a slight loss of power due to the mechanics of the fan, but the upside definitely compensated for that. The whole paddock went crazy when they realised what Gordon had created, notably Chapman and Andretti, who were simply vigorous in their objections. Bernie told us not to rev the motors in the pit lane as you could see the chassis getting sucked closer to the ground. During the race, I was behind Patrese who was fast in a straight line, made a move, went off track and that was that. Niki won and the fan car never raced again”.

Niki Lauda told the press in early 2018: “I remember that weekend very well. Ecclestone said ‘full tank qualifying!’. I said no way, I can’t do it. Out there are quicker guys. But he kept repeating it, ‘full tank qualifying!’. When the race started, it was Pironi who lost his oil, it was spread all around the circuit. I saw it from the back. Other drivers tried to avoid it but I drove full throttle on oil land with my downforce advantage and soon I was in the lead. Overtaking Andretti was just so easy, I could do it from outside – that’s how high the cornering speed was since the car was completely sucked to the ground”.

A good question is what could have been achieved if the BT46B wouldn’t have been removed from the competition? Again, John Watson has the answer: “Had the fan car not been withdrawn, NOT banned, then there would have been a mad rush by the leading teams to follow suit. Only Ferrari had a similar layout as Brabham. Also, the potential increase in lap speed would have altered the view of circuit safety for spectators and drivers. The decision to withdraw the whole idea after Sweden was the correct one, ultimately it could have broken FOCA and everything they were in process of trying to achieve”.

The Brabham BT46B raced again only once, at the Gunnar Nilsson Memorial Trophy in 1979, at Donnington. In the hands of Nelson Piquet, it finished 4th. Then it went to the museum.




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