Thursday, 23 June 2016 09:00

Brabham BT46B: Gordon Murray reinvents the fan

Written by

Translated by Giannis Binas


Formula 1, being the pinnacle of motorsport, continues to be the tip of the spear in car technology evolution in spite of the modern strict regulations.

The inherent competitiveness of the sport had, at times, driven the designers into extreme solutions in the limit of the regulations in order to reach the extra mile in the single-seater’s performance.

On the previous decades, the ground was more suitable resulting in the appearance of cars at the grid that one way or another caused a stir, many reactions, and, inevitable, regulation changes.
The Brabham BT46B by the hand of Gordon Murray is a classical example…
In 1977, Colin Chapman had presented the revolutionary Lotus 78, which was designed in the light of “ground effect”, achieving high values of downforce.
The leader of Lotus, together with designers Tony Rudd and Peter Wright, were based on the Bernoulli’s principle, according to which when the air flows through a small sized channel, its speed increases and its pressure drops.
The floor of the Lotus 78 exploited this principle channeling the air through diodes (venturis), which began from the front og the radiators and reached up to the diffuser, while, simultaneously, rubber ‘skirts’ extending from the sides trapped it in the single-seater’s limits.
The 78’s speed in the turns was unprecedented but, naturally, had the expected youth and reliability problems; nonetheless, Lotus took 5 wins and 7 pole positions with Mario Andretti finishing 3rd in the championship.


Gordon Murray accepts the challenge

In the beginning of 1978, the South African designer of Brabham, Gordon Murray, had realized how exactly the Lotus was so fast and started thinking of ways to implement it on the BT46.
His hands were tied though, due to Alfa Romeo’s 12-cylinder flat engine the team was using as it was completely incompatible with the gorund effect philosophy.
Due to the opposite pistons, the engine was pretty wide, occupying the whole rear of the car, without leaving enough space for the venture diodes that had to be created.
The same problem was faced by Mauro Forghieri at Ferrari, which was also using the same configuration for its own 12-cylinder, as opposed to Lotus, which had the “evergreen” V8 Ford Cosworth whose compact dimensions were ideal for the development of the phenomenon.
The need to compete with Lotus (that, meanwhile, had presented the more complete 79 in Belgium) drove Murray to draw inspiration from the pioneer of the ground effect idea.
In 1970, Jim Hall competed in the North American sportscar championship (CanAm) with the Chaparral 2J, the first vehicle that used the technology.
The American was using 2 engines with the second giving motion to two fans in order to accelerate the air under the car and create negative pressure, but proved unreliable and was also banned by the regulations.

photo 2

In Formula 1, the moving aerodynamic solutions weren’t allowed but teams could use fans provided the 55% of their energy was used to cool the engine.
The perceptive South African had found the loophole in the regulations he needed as it was shared secret in the paddocks that the 12-cylinder Alfa Romeo produced serious amounts of heat and was difficult to cool.
The challenge was big and it took him 3 months to prepare the single-seater.
Brabham BT46B had an aircraft type pressure sensor in front of the driver’s seat, a wider front wing, flexible skirts that extended to the rear, while the engine space was sealed so the low pressure air flow under the car wouldn’t get interrupted.
On the rear, the vertically positioned 18-inch fan was sucking air from a radiator that was mounted horizontally on the engine, getting motion from the gearbox through a complicated series of clutches.

photo 3

They were limiting the fan to 8000 rpm so that it wouldn’t cause problems to the gearbox function or the engine’s.
The blades of the fan were built with magnesium as the materials used initially, such as plastic or glass fiber, couldn’t withstand the pressure.
When the car was completed, Murray’s measurements gave him astronomical figures of downforce and he decided to use it immediately at the incoming Swedish race.
Niki Lauda, that had left Ferrari in the end of 1977, expressed concerns for the project, as, in order to keep the engine revs high, the car should turn by accelerating, something that would expose the driver to high lateral G-forces.

photo 4
The premier and the reactions


The stir caused by the ΒΤ46Β at the paddock of Anderstorp had no match, as the fan was covered by a lid unifying all the teams’ personnel in wondering what was under it.
Inevitably, Brabham’s owner, the known and non-except Bernie Ecclestone, and Gordon Murray were called to answer a lot of questions that, of course, had to do with the ‘legality’ of the car.
Colin Chapman, after personally inspecting the single-seater, was the first to speak of an unfair advantage, forcing the organizers to perform a thorough control.

photo 5

Them, accepting Murray’s explanations that the primary purpose of the fan was to cool the engine and that the production of downforce was a ‘beneficial side effect’ (which stood), allowed its participation.
Ecclestone advised the team’s drivers, Niki Lauda and John Watson not to move fast in the first tryouts of the car in order to avoid further protests.
But the ‘fan car’s’ (as was baptized at the paddocks) speed was such that they had to fill up its fuel tanks during qualifying to slow it down (!), a move that allowed Mario Andretti to claim the pole position with the Lotus 79, having Watson and Lauda behind.
The rest of the teams couldn’t believe in their eyes watching how Brabham’s single-seaters were sticking to the ground from the produced downforce each time their drivers were touching the throttle.
The political games had already started with Chapman and Andretti in the front, who were saw a certain championship becoming disputed and started to search for ways to cause the banning of the ‘fan car’.
Especially the American star was spreading that the Brabham was flinging rocks, dust and other debris from the track towards the following drivers, something that Murray rushed to contradict with arguments such as the speed of the fan, which didn’t exceed 55 miles per hour, as well as that due to the centrifugal force, anything that escaped the fan would head to the sides.

photo 6

And while the propaganda was raging, Colin Chapman called Lotus’ designer, Peter Wright, informed him of the developments and asked him to design something similar for the 79.
On Sunday’s race, Andretti took advantage of the pole position keeping the lead for 35 laps until a little error allowed Lauda to overtake him and stay there, finishing 34 seconds ahead of Patrese and Peterson.
Andretti retired from engine and Watson in the other Brabham with a throttle problem.

Highlights from the 1978 Swedish Grand Prix


Bernie performs a tactical retreat

Despite the other teams’ objections, FISA ratified the result and Lauda kept the win, thepressur however on Ecclestone o retire the ‘fan car’ got even more intense.
1978 was the founding year of the Formula One Constructors’ Association (FOCA) that would play a primary role in the dispute with FISA in the beginning of the next decade and Ecclestone had risen as an undisputed leader with the support of the other owners.
With Colin Chapman and Ken Tyrrell moving the threads, the owners threatened to withdraw their support towards Ecclestone, who, having set as a target to exploit the broadcasting and commercial rights of F1, chose to retreat.
In contrast to what is generally believed today, the ‘fan car’ wasn’t banned.
It’s just that Bernie withdrew it, something that wasn’t particularly pleasing for Gordon Murray but he had nothing to do with it.


photo 7

The Swedish Grand Prix was a milestone in the course of the league.
What would have happened if Bernie hadn’t retreated?
Lotus might not have won its last championship in 1978 and Mario Andretti might have never become a champion.
Ronnie Peterson might still have been with us.
Brabham might have created a dynasty and we would talk today for the ‘fan car’ era instead of the one of the wing cars.
Bernie might have not gained the influence he has today and F1 could be completely different.
If, if, if…

f1grip avatar 240px 2013    autowebtv  rocketweb logo lizard 250    

Newsletter Sign Up