Nine things you may not know about Brabham’s iconic F1 fan car

Written by orobulletin

The Brabham BT46B, known as the Fun Car, only raced once in Formula 1.

Most F1 fans know the basic story of Gordon Murray’s car, which won the 1978 Swedish Grand Prix in Niki Lauda’s only race appearance. Team Lotus’s Ground Effect As an answer to his innovation, the Brabham’s rear-mounted fan draws air from under the car’s floor while the side skirts seal the sides and pull it to the ground to achieve a similar effect. produced. of the floor.

But there’s more to the story than that, and there are some legends that aren’t exactly accurate.

Alfa Romeo needed a fan car

Team Lotus first ran ground effect cars in 1977, but it wasn’t until the Lotus 79 came out in 1978 that everyone realized the potential of such a concept. This caused a rush for rivals to create their own ground effect designs.

But Brabham had a problem. The car had a chunky flat 12 Alfa Romeo “Boxer” engine. This architecture meant that the traditional ground effect his attempt to create a venturi tunnel was fundamentally compromised. This led to consideration of a twin-chassis design that proved too heavy and gave rise to the idea of ​​a fun car.

Carlo Chiti, Alfa Romeo’s head of engines, said: “Gordon Murray was, and still is, a very good engineer.

“It was impossible to create a ground effect vehicle due to the boxer engine, so he came up with the idea of ​​rear ventilation, which guaranteed the same physical advantages as the Lotus, and fitted with a skirt. rice field.”

The fan was hidden by the lid of the trash can


News of the fan car has been circulating long before it came out, but Brabham has been conducting behind-the-scenes tests at Brands Hatch and Alfa Romeo’s Barocco Proving Grounds, and Anderstorp also wants to keep details of its design under wraps. was As a result, fans were covered.

But while today’s team was building custom-fit shrouds on their own, Brabham mechanics found a much simpler solution and happened to find a trash can lid that fit the fan perfectly.

It cost about 30bhp


The fan was not powered by its own motor, unlike the 1970 Chaparral 2J “sucker car” that pioneered the fan car concept in racing at Can-Am. Instead, it was powered by the Alfa Romeo engine via a complex system that included four or more clutches, connecting the fan to the lower shaft of the gearbox.

That meant about 30 brake horsepower was going to the fan instead of the wheels.

However, it was an acceptable trade-off, as the increased downforce and corner speed were worth the significant increase in lap times.

The fan was mainly for cooling… sort of

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The fans obviously draw air from the underfloor sealed off by the side skirts to create downforce, but the rules prevented this from being their primary purpose. The reason was the wording of the regulation.

A 1978 change included a warning in the rule prohibiting moving aerodynamic devices. This states that mobile aerodynamic devices are allowed if the primary purpose is not aerodynamics.

Fans have two influences on Brabham. One was to help suck the car into the ground, while the other was to increase the efficiency of the water radiator mounted horizontally on top of the Alfa Romeo engine.

To meet the regulations, all Brabham had to do was demonstrate that 50% or more of the effect was cooling.

As expected, five teams (Williams, McLaren, Lotus, Tyrrell and Surtees) started protesting even before the race started in Sweden. The basis for these protests concerned not only the primary function, but also whether the skirts were not fully attached to the sprung portion of the vehicle as regulations required.

Commission Sportive International legalized this car before the event and legalized it again in the face of this protest and found the skirt to be fixed to the spring part of the bodywork. Critically, the main function was cooling, even if aerodynamic effects were recognized.

Measurements taken by CSI during a visit to Brabham’s headquarters confirmed that more than 55% of fan power is for cooling.

Clearly, Brabham’s primary motivation for introducing the fan was aerodynamics, but some of the car’s genius was manufacturing it in a way that met this regulation through the way it affected cooling.

included tank parts


The fan itself has 7 blades and it took a lot of work to get it right. Initially, it was expected that the car would be ready for the Monaco Grand Prix in early May, rather than in Sweden six weeks later. was

The fan component itself was originally from the tank. Originally plastic and then glass fiber reinforced nylon, these had to be heavily reinforced with cast magnesium blades.

As Gordon Murray explains in his excellent book One Formula, 50 Years of Car Design, the fan hub was also recreated in solid aluminum at the last minute after another catastrophic failure.

“During initial testing, we had a catastrophic fan failure and tried different materials that seemed to work,” says Murray. “But in the next few weeks, we had another fan blade failure, so we cast it out of magnesium, which made the fan significantly heavier.

“With a week to go until Sweden, we had another catastrophic failure of our fan hub. We had enough time to machine two hubs out of solid aluminium, and the final assembly was tested. It was sent to Sweden without a trace.”

However, despite the lack of testing of the final version for fans, Lauda proved to be reliable enough to win the Anderstorp.

Lauda and Watson qualify with full tanks


Brabham drivers Niki Lauda and John Watson have been given strict instructions not to reveal the strength of their fan car. This also included being warned about the engine’s revs, given that it was visibly sucked into the ground in the pits.

But it also, at the direction of Brabham team owner Bernie Ecclestone, had a large number of cars in qualifying to stabilize what Niki Lauda called a “vacuum cleaner” in his famous book To Hell and Back. It meant running on fuel.

“The vacuum cleaner was ready in time for the Swedish Grand Prix at Anderstorp. Our biggest concern was to show its undeniable superiority and abandon the game,” said Lauda. said.

“John Watson and I ran the qualifying lap with a full tank and did our best to avoid pole position.”

This explains why Mario Andretti took pole position for Lotus, while Watson took pole position two places ahead of Lauda and about 0.7 seconds ahead of the two Brabhams.

During the race, Lauda said he “played cat-and-mouse” with Andretti before easily passing him and winning “embarrassingly easily”.

was not banned in 1978


It’s often said that the fan car was banned after its only race, but despite Brabham’s withdrawal from the competition, this is not strictly true.

A CSI analysis of the car concluded that it was legal according to the regulations, with a wording change only made in 1979. CSI tried to frame it as a ban, but there is much more to the story. something happened.

Brabham team owner Bernie Ecclestone has said his position within FOCA (the Formula 1 Constructors’ Association he leads) has meant that the fan car’s dominance performance and the potential cost of being weighed down by its rivals is a factor. I knew that I was being compromised by the impact. Beaten and have to respond.

So he was persuaded to drop it, creating what could be presented as a ban for the rest of 1978, even though the car remained legal for the remainder of 1978. did.

There was a design for the second fan car


The Brabham BT46B was just Gordon Murray’s first attempt at a fun car. It was a virtual cut-and-shut job of modifying an existing BT46 to make the most of the concept.

But Murray was already working on a bespoke fan car, the Brabham BT47. Given a rule change that banned such designs in 1979, the car was never raced and was never actually built.

The initial design had two important changes. First, as Murray explains in his book One Formula 50 years of Car Design, the fan speed is variable.

“We were looking at a variable-pitch fan driven by the speed of the car, but it basically feathered on the straight, and the cooling was reduced in that short amount of time, and the car didn’t get hot enough.” Murray said. “Then when we got to the corner the fan kicked in again.

This allows it to generate ground effect downforce in corners, but doesn’t absorb as much power on the straights.

Murray wrote Brabham BT48 instead. Despite Chiti producing his new V12, Brabham, unreliable and compromised by the chunky Alfa his Romeo engine, saw him only eighth in the constructors’ championship.

Fan car participates twice

Funker only raced once, but also took part in a time trial event at Donington Park on 3 June 1978.

It was one of only five cars entered in the non-Championship Gunnar Nilsson Memorial Trophy. That alone wasn’t enough for the race, but the car practically ran in a glorious qualifying session.

Driven by Nelson Piquet, the event was won by Williams driver Alan Jones, who finished fourth. James Hunt (Wolf), Mario Andretti (Lotus) and Rupert Keegan (Arrows) were the other competitors.

The Brabham BT46B fan car is one of the most remarkable cars in Formula 1 history. Murray’s genius enabled an elegant solution to the problems posed by the success of the Lotus 79 and the limitations he had to grapple with to accommodate.

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