Gordon Murray talks fans on BT46B, F1 and T.50s
As he presented his brand-new T.33 supercar in the Goodwood paddock for the first time, we caught up with Gordon Murray. To talk fans. No, the other kind.
It’s one of the key features on the T.50s, professor Gordon Murray’s successor to his McLaren F1. It is released under his own brand Gordon Murray Automotive. The T.50s is a track orientated supercar, weighing just 852 kilos and powered by a 3.9-litre Cosworth V12 that puts out close to 730 hp. The engine revs right up to 12,100 rpm. It is insane and it is already sold out. Just 25 will be made.
The thing that stands out at the rear is the fan. And it is not just a visual cue to Niki Lauda’s famous Brabham BT46B fan car, which won the 1978 Swedish Grand Prix. The fan on the T.50s is 400 millimetres wide and plays an integral role in creating downforce. Just like in the old days. “If you like, it’s an idea that started in 1978 in racing and is still around today,” Murray muses. We take a moment at the 79th Members’ Meeting in Goodwood to talk about the past and present.
“The Brabham fan car was a completely different concept,” Murray explains. “It was a way of getting around the regulations. The flat-12 Alfa engine precluded us from doing a wing car like Lotus. It was born out of a necessity really, and I found a loophole in the regulations. The fan on the BT46 was a crude device. It was literally skirts and a vacuum cleaner really (laughs). And we got around the rules by having 60 percent of the air helping to cool the car and 40 percent was used for sucking it to the ground. We never pretended it didn’t suck the car to the ground, but the majority of the fan’s function was for cooling.”
In its first race, the 1978 Swedish Grand Prix at Anderstorp, Niki Lauda won straight out of the box. There were instant calls to ban the fan car. “The CSI – the technical wing of the FIA at the time – came and sealed the car straight after the race. They watched us put the car on the truck, sealed the truck and the car came back to Chessington with Brabham. We couldn’t open the truck until they arrived. And they had brought anemometers to measure airflow.”
“They made us rev in 1000 rpm steps, up to 11,000 rpm. They measured the air through the fan and the air through the radiator. By design, I wanted 55 percent for cooling and 45 percent for downforce. They measured 60 percent for cooling. And so, they wrote us a letter telling us we could run the car until the end of the year, ‘but then we will close the loophole’.”
“That was a shame because I already had a BT47 on the drawing board with two fans with variable pitch blades. This way, we wouldn’t lose horsepower to feed the system down the straights. The blades would just be used for the corners. That was already on the drawing board.”
“Unfortunately for me, Bernie Ecclestone – then my business partner at Brabham – was getting powerful in the Formula One Constructors’ Association. And Colin Chapman with Andretti and his wing car could see his championship disappearing because we were two seconds a lap quicker. Sweden was in June, so we still had quite a few races to go. Chapman realised that every race we finished, we would win. Easily. So, he got Ken Tyrrell and a couple of the others together and they wrote to Bernie. They said: if you continue to run this car, that’s the end of the constructors’ association.”
“You know, Chapman was very good at politics as well. He was my hero when I was growing up, but I raced against him, so we were very tough competitors. And Bernie came to me and said: ‘what do you think? It’s very important for Formula 1 that we keep the constructors’ association. Should we withdraw the car?’’
‘Of course, my answer was ‘absolutely no way.’ Because I could see a championship for us. But eventually, he convinced me it was good for the sport. I was really upset. So upset in fact… See, we built three fan cars. We only had time to assemble two. A third one sat ready in the truck but was not assembled. And I was so upset I got the mechanics to take it to the backyard and cut it all into pieces and throw it in the bin.”
On McLaren F1 as well
“When I did the McLaren F1, I used a lot from racing. It was the world’s first ground effect car, it was the world’s first carbon fibre car, carbon clutch. I mean, it just took a lot from Formula One. But what most people don’t know, is this: the F1 has two small fans. They are about 150 mm diameters each and they sit in the side of the engine bay. And I had a step diffuser on that. It’s just an idea I had because obviously, you can’t run skirts on a road car.”
“I could see how effective the fan was. I thought, what if we had two diffusers this wide with a steep change? If I can remove the boundary layer, the dirty air will force the air to follow that and increase the lift over drag. And it works. But because it was just two small fans, we only got a five percent increase in efficiency.”
“Most people just missed this because the F1 had so many firsts and everyone forgot that. These fans sit on either side of the bulkhead, that area. I put one down in the memory bank and said: ‘if ever I do another road car, I would like to do a bigger fan and do it over the complete diffuser.’ Not just on a little part, but the whole diffuser. So, when we started 50, it was a natural thing to do. But actually, although it was inspired by the 46B Brabham, it’s not the same system at all. It’s much more sophisticated than it was. As I have said: the 46B was a vacuum cleaner.”