80's F1 Cars

Brabham BT 46


FORMULA One racing has a long history of controversy and disputes but it is relatively rare for there to be a serious argument about the legality of one particular car. This is because the rules governing Grand Prix racing, which have been arrived at through some consultation with the constructors, are for the most part water-tight. A couple of months ago a serious dispute did brew up over the legality of Brabham's latest F.1 racer, the BT 46/B. Happily the squabble was soon settled; but the car was declared illegal and this has not satisfied many people connected with F1 racing who maintain that the BT 46/B was a brilliant piece of innovative design. There are of course many others who think that the BT 46/B should never had been allowed on the race track as it constituted a flagrant breech of the rules. In simple terms the car was deemed to be illegal because it was fitted with a cooling fan which also helped to keep the car on the track.

Basically the wrangle over the BT 46/B concerned the definition of an aerodynamic device as laid down by the CSI. According to the rule book any part of the car whose primary function is to influence aerodynamic performance is held to be an aerodynamic device and as such must be firmly fixed whilst the car is in motion. This rule had been designed to ban both movable airfoils and the fans fitted to the Chaparral sports car some years ago which sucked the car to the ground using the reversed hovercraft principle.

To analyse why the BT 46/B came to be fitted with such a "fan, and to attempt to ascertain its legality it is necessary to look back to August 1977 when the first BT 46 was shown to the press. One of the central considerations in designing a racing car is the placement ofthe oil and water radiators. Their position dictates the general layout of the car and any change in position after the car is built can upset completely the balance and performance of the car. The BT 46 in its original guise was built without normal oil and water radiators in their place heat exchangers were constructed flush in the sides of the car's monocoque chassis. This revolutionary feature gave the car a very small frontal area, and allowed designer Gordon Murray to build an impressively clean racing car. Unfortunately for Brabham the surface cooling system didn't work and so Murray had to compromise and fit radiators in the nose of the car, which immediately upset all his calculations and the car's performance.

The BT 46 made its debut in this year's South African GP but despite a fine turn of speed, it became apparent that in front radiatored form the car would not be winning many F1 races. The reason being the JPS Lotus 79, a frighteningly advanced F1 design, which in terms of design features could be said to be two years ahead of the opposition.

Almost as the BT 46 made its debut in April, designer Gordon Murray set about re-designing the car to bring it into the same ball park as the JPS. The work was completed three months later, and the result was of course the 'fan-car', the BT 46/B. Basically Murray's design brief was to recover the original balance and airflow ofthe BT 46 which had been completely upset by fitting conventional radiators in the front of the car. Murray found an ideal position for the radiator, lying flat on top of the car's flat-12 Alfa Romeo engine. The problem he was now faced with was how a radiator in this position could receive sufficient airflow to cool the car. At Argentina the BT 45/C Brabhams had been fitted with small fans to draw air through the radiator; Murray's method of cooling the BT 46/B's radiator was, to him, a logical extension of this principle. The rear end of the BT 46/B was completely enclosed, save for the upper surface of the radiator and a large circular orifice at the car's extreme rear, into this orifice was fitted an extremely large and efficient fan, driven from the gearbox mainshaft.

If this had been all there was to the system I am sure that the BT 46/B would still be running in F1 races today, Murray however carried the fan concept to its logical conclusion. Instead of fitting ducting from the bottom of the radiator to the fan, the insides of the car's rear were arranged so that the fan sucked air from around and under the engine, and also from under the car. By placing flexible skirts around the car the underside was effectively isolated so the fan was sucking much of the air from beneath the car, creating a low pressure area and therefore sucking the car down to the ground.

This of course was the negative hovercraft effect which had been seen on Jim Hall's Chaparral 2J and banned.

As soon as the BT 46/B appeared in practice for the Swedish GP all hell let loose, the major argument centring around what the primary function of the fan was. The Brabham team were unanimous in the claim that the primary function was to cool the radiator. The majority of the other F1 constructors were sure that the fan's primary function was as an aerodynamic device, and that it was therefore illegal because it was movable, not 'firmly fixed' as the rules demand. To further complicate matters the CSI had declared the car legal without seeing it, and so there was nothing the Formula One Constructors Association, the chairman of which is Bernie Ecclestone, Brabham supremo, could do to prevent the car running in Sweden. It was around these two words, 'primary function', that the main controversy about the BT 46/B raged.

There was no argument that the Brabham's fan did have an aerodynamic effect on the car, even when the car was standing still it was easy to see the BT 46/B moving up and down as the engine was revved. The main result of the negative hovercraft effect is to increase cornering speed, and Mu rray and the Brabham drivers didn't deny that the fan did this, however their argument was that this was only a secondary effect of the fan. While the arguments went on in the pits the Brabham drivers Niki Lauda and John Watson quietly got on with the job in hand which was to get the BT 46/B in proper shape for the forthcoming race. At first the system did not work because the flexible skirts were not effectively sealing the underside of the car and so air was entering the low pressure area from around the car negating the fan's effect. Once the underside was effectively sealed the Brabhams began to really motor and Watson and Lauda qualified behind Mario Andretti's flying JPS, in second and third places on the grid. The race itself saw Lauda dog Andretti until just after half distance when he slipped by the JPS. A couple of laps later the JPS's engine destroyed itself as a result of the strain it had suffered in keeping ahead of the BT 46/B. Niki Lauda was therefore able to cruise to victory by half a minute having smashed the lap and race record by over 3 m.p.h. This was Brabham's first victory for three years, their first with the Alfa Romeo engine, and Alfa's first since 1951.

The Swedish GP proved to be a convincing demonstration of the BT 46/B's potential and increased the desire of a number of constructors to have the car banned. Frank Williams immediately made an official protest about the car Colin Chapman, John Surtees, Teddy Meyer and Ken Tyrrell having entered protests before the race had even begun. The organisers of the Swedish GP passed the protests onto the CSI and everyone expected "a long drawn out battle to establish the car's legality. Surprisingly, within a week the whole affair appeared to be settled.

On the Tuesday following the race the BT 46/B's were examined by three representatives of the CSI, with the full cooperation of Brabham. Two days later on June 29 the Formula One Constructors Association met to discuss the car. This 6.5 hour meeting undoubtedly was very heated, it was also very important for the future of F1 because if the FOCA were to split over the fan car the repercussions for the future of F1 racing would be simply incalculable. Common sense prevailed and a compromise was arrived at, the BT 46/B was to be allowed to race until August 1st, it would then be banned for good and all. The FOCA took this formula to the special CSI meeting on June 23; surprisingly the CSI did not accept its recommendations and banned the car immediately, pending a report of the technical regulations sub-committee of the CSI, then new rules would bee written concerning fans. This decision, which was taken on the casting vote of the chairman was made for reasons of safety. The CSI, particularly chairman Pierre Ugeux, was very worried about the effects of the increased cornering speeds possible with the 'negative hovercraft effect'. There were two main worries, firstly that safety standards which were adequate with the current cornering speeds would become inadequate. Secondly they were worried about what would happen. if the fan stopped or broke in the middle of a corner, the car would then, it was feared, be travelling too fast and may crash. A further safety aspect was the amount of grit, dirt and debris swept up by the fan and blown out of the rear of the car. Mario Andretti had been particularly vocal about this aspect of the BT 46/B in Sweden; he was afraid that a driver might end up with a bolt blown through his helmet. Certainly in Sweden Emerson Fittipaldi had been forced to stop in the pits following one of the Brabhams for a lap or so in practice, his visor and eyes had been clogged with dirt. . .

Not surprisingly the Brabham team was livid, Gordon Murray, usually one of racing's quiet men, was particularly scathing about the decision to ban his brain child. He was very critical of Colin Chapman's statement that the fan was substantially bigger than it needed to be. He also accused Chapman, Meyer and Tyrrell of being against the BT 46/B for purely political reasons, namely that it would make their current cars, and new designs which McLaren and Tyrrell were known to be working on, obsolete. Murray was understandably upset at seeing three months flat-out work come to nothing. For the next race the BT 46 was back to normal, minus the fan, and unlessthe CSI make a surprising about face, it appears that it will never race again.

What is, I think, clear is that it certainly contravened the spirit of the rules as they stood. Murray claims that the fan was the minimum size needed to cool the car; he was the designer and we have to accept this assertion, there can therefore be no reason why the car should have been banned. He also stated the Brabham had deliberately broken one of the fan blades and stopped the fan in the middle of a corner with no ill effects; thus quelling one of the main fears about the car's safety.

If we look on the other side of the coin there is equally convincing evidence. As I have said, the BT 46/B is outside the spirit of the laws, the law being drawn up tp prevent fans on racing cars. There is also the safety aspect which makes the adoption of fans so dangerous to some observers. Are increase in cornering speeds goes against everything the F1 safety fiends have been trying to achieve over the past few years. If the fan had been ducted from the underside of the radiator no one would have been in any doubt as to its primary function, but then it wouldn't have had a secondary function and there would have been no fuss.

Gordon Murray deserves ten out often for bringing some new thinking to F1 racing, his BT 46/B was an excellent design, beautifully put together and it worked like a dream.

Murray's design was the first, if the concept had been allowed to develop and become more sophisticated there is no telling what the increase in cornering speeds, and therefore the risk, would have been.

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Author: ArchitectPage