Story of the Legendary Brabham BT46B Fan Car and Some Forgotten Facts About It

Most people know about the basic story of Gordon Murray's car, which won the 1978 Swedish Grand Prix at the hands of Niki Lauda (a two-time world champion at that time), who moved from Ferrari to Brabham right after winning both the drivers' and constructors' championships. The BT46B was more of an answer to the ground-effect innovation made by Team Lotus. As a result, Brabham came up with the idea of placing a large fan at the rear of the car. This method created a similar effect by sucking the air out from below the vehicle pulling it closer to the ground, and sealing the underfloor with the side skirts.

Still, there is a lot more to the story of the Brabham 'fan car' than meets the eye. As a result, we will present you with some of the most important details and even some legends about one of the most legendary and fan-favorite cars in the history of Formula 1. Let's get right into it.

Team Lotus had first run a ground effect car in 1977, with the British squad being kind of the pioneers of this technology. However, it wasn't until 1978 and the Lotus 79 that everybody realized the potential of such designs. It triggered a rush for rivals to create their own ground effect concepts. Unfortunately, Brabham had a problem because its car was powered by the chunky Fiat 12 Alfa Romeo boxer power unit. The architecture meant any attempt to create conventional ground effect Venturi tunnels was basically compromised. That was primarily due to the cylinder heads being in the way. As a result, this led to the consideration of a twin chassis design which, in the end, proved too heavy. Then the idea of the 'fan car' came up. Besides, Carlo Chiti (Alfa Romeo engine designer) went to work to design the V12 Alfa Romeo power unit, which was used in the 1979 Brabham model.

The news got out about the 'fan car' long before it appeared in public, but while that was happening, Brabham had conducted its testing in private at the Brands Hatch circuit and the Alfa Romeo personal testing track. They wanted to keep the details of its design hidden as long as possible, so they covered the fan. Simple as that.

The fan was not driven by its own motor; instead, it was conducted through a complicated system connecting the fan to the gearbox's lower shaft and incorporating no less than four clutches. The Alfa Romeo engine powered the fan, which meant that around 30 brake horsepower (30 PS) went to the fan rather than the wheels. Still, that was a good enough trade-off because the downforce gain was worth enormously.

While the fan was creating downforce by sucking air from the underfloor (which was sealed by the side skirts), this wasn't its primary purpose because of the way the regulations were worded. In 1978, the FIA banned movable aerodynamic devices included, but not totally. You see, they declared that movable aerodynamic devices were permitted if their primary purpose was not aerodynamic. There were two effects of the fan on the Brabham car. One was to help suck the car to the ground. Still, the other was to increase the efficiency of the water radiator mounted horizontally on top of the Alfa Romeo power unit. In order to prove legality, Brabham needed to show that more than 50% of the effect was cooling. As you might expect, five teams (McLaren, Lotus, Williams, Tyrrell, and Surtees) launched protests even before the race started in Sweden. The basis for these protests concerned the primary function and whether the skirts were fitted entirely to the sprung part of the car, as the regulations demanded.

The CSI (Commission Sportive Internationale) had ruled the car legal both before the events and after the protests. The CSI measurements obtained at the Brabham headquarters established that more than 55% of the power of the fan was for cooling. However, Brabham's primary reason for introducing the fan was obviously aerodynamic.

The fan itself featured seven blades and required an enormous amount of work to get right. Initially, the engineers hoped the car might be ready for the Monaco Grand Prix in early May rather than for the Sweden Grand Prix, which was six months later. As a fun fact, the fan components themselves originally came from a tank. At first, they were made of plastic, then glass fiber-reinforced nylon.

Brabham drivers Niki Lauda and John Watson were under strict instructions not to reveal just how quick the 'fan car' was. The officials of the Brabham team were so serious about these rules that they warned the driver about how much they could rev the engine in the pits so the rivals would not see how much the car was sucked to the ground. At the same time, team owner Bernie Ecclestone told the drivers to run on a heavy fuel loading in qualifying to ballast the BT46B.

Both Lauda and Watson did everything they could to avoid the pole position. As a result, Mario Andretti from Lotus took the pole with an advantage of 0.7 seconds over the two Brabham cars. In the race, Niki played cat and mouse with Andretti before overtaking him quickly and winning with so much ease. Unfortunately, that was the only victory.

While it's often said that the 'fan car' was banned after its only race, this is not necessarily true, even though Brabham withdrew it from the competition. The CSI analysis of the car concluded it was legal, saying they would change the rules in 1979. So there was no ban in 1978, but still, it's a lot more to the story. Brabham team owner Bernie Ecclestone understood that his position within FOCA (Formula One Constructors Association), which he headed, had been compromised by the BT46's dominant performance and the potential cost implications of the rival team, which had to respond. As a result, he was persuaded to drop it despite it being legal, making everybody believe that the car was banned. Now you know the actual truth.

For the upcoming season, Gordon Murray abandoned the 'fan car' concept because it was banned, so he started working on the BT48. Unfortunately, this car was unreliable and still compromised by a chunky Alfa Romeo engine, even though it was now a V12. The team managed only eight in the constructors' championship.

Another unknown fact about the BT46B is that while it raced only once in F1, it did compete in the Gunnar Nilsson Memorial Trophy, a time trial event at Donington Park in the summer of 1979. Nelson Piquet drove the 'fan car' and finished in P4, right behind defending Formula 1 champion Mario Andretti.

This was the story and some unknown facts about what could have been the most dominant car in Formula 1 history. Still, even if it participated in only one Formula 1 Grand Prix race, the Brabham BT46B left an important mark in the motorsport world. Besides, to better understand how good the engineering of this car was, check out this 3D video about it.