Formula 1's ultimate one-hit wonder

It suddenly dawned on Brabham as the 1978 Formula 1 season was beginning that it had a problem. No one had quite cottoned on to what Lotus had found with the previous season's type 78, but the lightbulb came on with the appearance of the 79 in winter testing.

There began the thought process in the fertile mind of Gordon Murray that spawned one of the most controversial grand prix cars ever in the Brabham BT46B, the fan car of one-race, one-victory fame.

The problem the British team had was the flat-12-cylinder powerplant that came with its Alfa Romeo deal. Brabham designer Murray knew it was, quite literally, an obstacle to generating the same kind of downforce as the latest ground-effect Lotus. Just where the venturi underwings should have been sweeping upwards, Murray had immovable objects in the form of Italian four-valve cylinder heads.

"By the time Lotus did the 79 [below], everyone was starting to suss what they had discovered," explains Murray. "If you had a Cosworth, you just swept the exhaust pipes up where you wanted the diffusers to start, but we were stuck with a flat-12 engine.

"I said to Bernie [Ecclestone, then Brabham's boss], 'We've had it. Lotus are going to walk away with this unless we do something.'"

The first solution to the problem studied by Murray was arguably even more creative than the fan-car concept. The immovable object moved courtesy of an innovative car layout.

"I drew up a twin-monocoque car that had one very short tub with the flat-12 strapped immediately behind the driver," says Murray, "and then a second smaller and narrower tub on the back of the engine. That was where the fuel tank was, and the propshaft went through a tube in the middle to the gearbox. The plan was that it would come out in the middle of the season.

"I came up with this idea and drew it all out, and then I did a weight calculation. Already our flat-12 was much heavier than a Cossie and the Ferrari engine as well. It was really, really heavy. I thought, 'No, the weight is going to kill us.'

"I remember thinking that we had to find another way to get the downforce, and that's where the fan car came in."

A year previously, a fan car that sucked itself onto the track - rather than a ground-effect machine that was sucked - would not have been possible. Moveable aerodynamics were banned, but over the winter of 1977-78 there was an addendum to the rulebook that opened the door. The new clause stated that a moveable aerodynamic device was permissible so long as that wasn't its primary purpose.

Exactly why the rule change was made isn't entirely clear, but it appears to have been introduced to cover the widening use of underbody skirts, which had been creeping into F1 even before the arrival of the Lotus 78. Skirts were clearly moveable, although what purpose they had that wasn't aerodynamic isn't clear.

Murray (pictured below) took the new regulation to a lawyer: "I asked him, 'If you have got something that says primary function, what does that mean?' The lawyer said, 'How many functions are you talking about?' When I replied, 'Two', he explained that the primary one was the one that was more than 50%."

Murray knew there was a loophole to exploit. Hatching the idea of the fan car was one thing - "a 10-year-old could have thought of that," says Murray - making it work quite another.

The Chaparral 2J Can-Am car of 1970 was barely an inspiration.

"That was entirely different," Murray reckons, "because it had an extra engine running the fans.

"Our fan car had four different clutches and a very complicated drive system, which all had to be designed, and then built and tested in three months.

Keeping the skirts on the road to maintain the seal around the underside of the car so the fan could suck the car down and draw air through the radiator sitting atop the engine was one problem to overcome.

"The skirts were mounted on long leaf springs, a bit like the hinge on the lid of a piano, which we could tune. If they were too stiff the skirts would wear out and if they were not stiff enough the fan would suck them off the road," says Murray.

"It was the transfer skirt at the front of the car that was more difficult because it had two forces working on it: the suction from the fan and the pressure of the airflow."

Murray's solution to the problem was somewhere between the ingenious and Heath-Robinson.

"We had a couple of sailcloth sausage bags behind the front skirt and there were a series of holes drilled in the front skirt that allowed them to inflate," he explains. "At a certain speed holes started opening in the first bag and blew it up like a balloon so that it added pressure to the back of the skirt to keep it down, and then eventually more holes aligned to inflate the second bag."

The fan itself was derived from one used for cooling on a Centurion tank, "or at least," thinks Murray, "from some kind of tank". The issue was making it stay together.

"The fans were nylon with glassfibre reinforcement," he continues. "They kept bursting, so we cast magnesium blades, but the hub in the middle was still glass-reinforced plastic."

Murray remembers carrying out initial development running with the BT46B at Alfa Romeo's Balocco test track in northern Italy. That was followed by a final session at Brands Hatch in the run-up to the car's appearance at the Swedish Grand Prix at Anderstorp in June.

"Now the hubs were exploding because they were heavier and had more centrifugal force," adds Murray. "With a week to go we machined the hubs out of solid aluminium. I think only one was complete when the cars left for Sweden, and we sent the others out separately and assembled them there. When we got to Anderstorp, we hadn't actually tested the final configuration, not at all."

The F1 world went apoplectic when the BT46Bs were rolled into scrutineering in the paddock in Sweden.

"There was pandemonium," remembers Brabham driver John Watson. "Ken Tyrrell was frothing at the mouth and [Lotus boss] Colin Chapman was going crazy."

It probably didn't help that Brabham opted to conceal the fans on the two BT46Bs behind convenient, neatly fitting dustbin lids.

"We found a dustbin lid that fitted perfectly," explains Murray. "We didn't want anyone to get close-up pictures of the blades and the pitch when we were running them up, but, of course, Bernie loves a wind-up."

The anger of Brabham's rivals was fuelled by the fact that the BT46B had already been declared legal by the Commission Sportive Internationale (CSI), then the sporting arm of the FIA. It had signed off the car at a meeting in Madrid earlier in the month, the day after Andretti had taken a second consecutive victory aboard the 79 in the Spanish GP. The CSI had not so much as seen the car.

Watson and new Brabham team-mate Niki Lauda were under instructions not to show what the car was capable of, even before it made it onto the 2.5-mile Scandinavian Raceway.

"Bernie kept telling us not to rev it in the pitlane," remembers Watson, "because every time we did, the thing sucked itself down onto the ground. The team didn't want us going too fast in qualifying, so they sent us out on full tanks."

Even so, Watson and Lauda qualified second and third respectively behind Mario Andretti's Lotus. Reigning world champion Lauda jumped to second at the start, trailed the American for 38 laps, and ended up winning by 30 seconds after the subsequent retirement of the Lotus. Easy.

Lauda reveals in his 1986 autobiography To Hell and Back that he "let Andretti go to play cat-and-mouse with him". He explains that, whereas the Lotus driver had to back off over a patch of oil left by Didier Pironi's Tyrrell, he was able to ignore it and "overtook him with embarrassing ease".

Murray has no doubts about what the BT46B was capable of: "We would have won every race we finished and taken the championship easily."

There probably wasn't much to choose between the Brabham and Lotus in the fast corners, but the fan car came into its own in the slow and medium-speed sections.

"We had maximum downforce in a first-gear corner and probably twice the downforce they had in a third-gear corner," he explains. "But we had to be quicker in the corners, because we lost 30bhp running the fan."

There was inevitably a protest after the grand prix, but the Swedish federation under whose auspices the event was run merely threw it out, pointing to the CSI's declaration of the design's legality. The challenge - led by Tyrrell and Lotus - did, however, result in Brabham's cars and trucks being sealed ahead of a full technical inspection by the CSI at the team's Chessington base back in the UK.

"They came with a handheld anemometer to measure the airflow through the radiator," recalls Murray. "Sure enough, it was more than 50%. I never said that the fan didn't suck the car down, just that more of it cooled the car."

Murray says he still has a letter from the CSI's technical committee confirming the legality of the car. "They said they agreed with my reading of the regs and there was a loophole, so good for you. But be warned, we will be changing the relevant rule - article 37, I think it was - at the end of the season."

The BT46B would never race again, however. But was it banned or was it simply parked by Brabham? It has come to be accepted that Ecclestone chose to withdraw the car to avoid a fight with fellow members of the Formula One Constructors' Association, the organisation through which he was laying out his power base in F1. That is absolutely the case, although Brabham's reversion to standard BT46s for the French GP at Paul Ricard in July was presented by the CSI as a ban.

Yvon Leon, then secretary-general of the CSI, was one of a three-strong delegation that inspected the BT46Bs at the Brabham factory on the Tuesday after the race. He confirms that the test with the anemometer did take place and was carried out by Robert Choulet, the famed Matra aerodynamicist who was retained by the CSI as a consultant.

"We made a report in which we said that the fan was not solely a cooling device," recalls Leon, "but there was no possibility of proving that it was counter to the regulations. I remember a discussion with Ecclestone in which he said he would withdraw the car so long as he could keep the Anderstorp victory. He had the other constructors against him, and I think that was very important in his decision."

Watson reckons that Ecclestone saw the bigger picture: "There was going to be a major confrontation and any split might take a long time to repair. His position of strength in F1 was founded on the unity of the constructors; without unity he didn't have a position of strength."

The Brabham designer wasn't best pleased. "Bernie came to me saying that the car was going to be the end of FOCA," says Murray. "He asked if I would mind withdrawing the car. I was spitting blood."

The decision resulted in two trips to the drawing board. Alfa Romeo had to begin work on a new V12 and Murray had to tear up plans for an optimised fan car to be known as the BT47.