Max Yamabiko: The real reason for a wind tunnel ban

The proposal to ban wind tunnels is being pledged in the name of reducing costs... but Max Yamabiko argues this is a simply a veil for less scrupulous reason
Max Yamabiko: The real reason for a wind tunnel ban

One of the bigger stories doing the rounds during the Singapore Grand Prix this weekend is the apparent proposal to ban wind tunnel usage in F1 seemingly in the name of adopting cheaper techniques and, ultimately, reduce costs.

For those who err on the more conspirator side of debate however, there is reason to believe that those pushing to outlaw wind tunnel testing in Formula 1 are not doing it on the grounds of cost control, but because they are keen to recover a competitive advantage.

Not that everyone appears necessarily fooled by this, which may explain why several teams came out to express their intention to resist such a move.

"I'm against banning wind tunnel usage because there's always a reason behind it. Some teams are pushing to ban anything, whatever it is, because maybe they don't have the proper infrastructure or maybe they have an advantage with another tool." Franz Tost of Toro Rosso told the press at Singapore.

Tost is absolutely right. The reason why this move to ban wind tunnels - subject to ratification - is so important is that despite all of the talk of power units and their overriding influence on the fortunes of the teams, F1 is still a largely aero dominated class of racing.

Essentially, F1 teams have three methods of doing aerodynamic testing. The aim of all them is essentially to get the most efficient aerodynamic designs possible - the most downforce for the lowest level of drag possible

The first is 'real world' where the real car is run on track using various instrumentation monitoring the air flow around the bodywork. You often see this in testing and sometimes in free practice 1 with large arrays of air speed sensors affixed to the car. Another technique used is flow visualisation dye, where a part of the car is treated with an oil or paint then sent out for a few laps. The dye then shows the air flow patterns across the bodywork.

For a long time teams conducted a lot of this testing during straight line runs at airfields such as Duxford in England. That practice was outlawed following the fatal accident suffered by Maria De Villota during a straight line test.

The second approach is wind tunnel testing. Normally this involves using a scale model of the car, with the maximum model size permitted in F1 to be 60 per cent after full scale testing at facilities like the Haas Windshear tunnel, was banned a few years ago on cost grounds. This ban was more to do with the amount of money being spent by teams on flying cars out to North Carolina than the actual cost of the testing. Wind tunnels use fans to suck air over a static car mounted on an artificial moving floor (called a rolling road) to simulate the air flows found in the real world.

The third and most modern approach is CFD, computational fluid dynamics, though I think the best way to describe this technique is the virtual wind tunnel. A computer simulates the air flows over the bodywork and give the results numerically or visually.

So how do these three methods compare? Well they each have their own merits and detriments. Real world testing is already very tightly restricted, and it can be very time consuming. Also it can be disrupted by external conditions, like crosswinds and other cars on track, not to mention the most variable factor, the driver.

Wind tunnels are extremely expensive to build and maintain. Operating them too can be very expensive in terms of staffing and electricity. However every F1 team, apart from Manor, has at least one wind tunnel, so much of that cost is already accounted for. Additionally there are a number of commercially available tunnels around Europe such as the popular twin tunnels at TMG in Cologne Germany. Indeed many team rent out their wind tunnels to other teams, Sauber's facility for example is regularly used by Audi Sport.

As for CFD, the virtual wind tunnel is simply not quite as accurate as the real world or a wind tunnel. However, it is quicker and able to process many more designs in a short time as no components need to be manufactured, which in turn makes it somewhat cheaper. For years CFD has been mooted as the future of aerodynamic development, and something which will make wind tunnel testing redundant.

However, as Nick Wirth and others have shown in recent years, the technology is not there yet since CFD only cars are just not as competitive as those designed using a wind tunnel.

The ideal approach for a team is to use all three techniques and try to get the results from each of them to be the same. This correlation is very important for aerodynamic development. It is important to point out that each of these techniques is heavily restricted by the F1 regulations; time in the wind tunnel is limited, the processing speed of the CFD super computers is limited and track testing is also heavily limited.

So why would anyone want to ban wind tunnels? Well, as Tost says, because either they don't have a very good wind tunnel or they have very good CFD. The performance of CFD systems will remain restricted otherwise it will develop very quickly into a spending race, so the team with the best CFD technique will suddenly get a big advantage.

As I understand it, the team with the best CFD ability is Red Bull Racing, which has a method of substantially reducing the processing time required to go from a CAD model of a component to getting a CFD result on it. This allows Red Bull (and others using the technique) to try out more different design ideas in the allowed times than the others can. If wind tunnels were banned, this technique would become a gigantic advantage, and this is reason some teams including Red Bull are pushing to ban wind tunnels.

Banning wind tunnel testing would only see budgets shifted to other departments and other techniques and it would almost certainly be hard to police. All it would achieve would be to allow some teams to have an unfair advantage. If Formula 1 really wants to take budget cuts seriously then the only solution is a global cost cap... but that's a debate for another day.

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