Countdown to F1 2011: Driver-Adjustable Rear Wings

A new feature to look-forward to (or dread) this year is a device designed to increase the amount of overtaking in Formula 1. The driver-adjustable rear wings will give any driver close enough to their rival a chance to lose downforce on a straight and, theoretically, be better placed to execute a manoeuvre into the next corner.

Here we explain what a driver-adjustable rear wing is, how it works, and how it will be used. To begin with, however, we look at the reasons why they have to be introduced, and what the powers-that-be hope that the new device will achieve.

A common complaint of many F1 fans is the perceived lack of overtaking in the sport, especially compared to other forms of racing such as touring cars. The main reason for this deficiency is the advanced aerodynamics of an F1 car in that, when one car closely follows another, it has to re-use the air of the car in front. This so-called dirty air has already been displaced and manipulated by the lead car and, when receiving it 'second-hand', the car following cannot take full advantage of it. As a result, the car behind experiences decreased aerodynamic grip when cornering, and struggles to keep close enough to its rival to mount a successful challenge for the position.

There have been many attempts to get around this problem. Last season, flexible front rings were introduced, allowing the drivers to change the angle of the wing when following another car. In practice, this did little to help, and these driver-adjustable flaps have been abandoned for 2011. The restrictions on diffusers introduced for the 2009 season, which Brawn GP, Williams and Toyota famously found the loophole that led to the double diffuser, were introduced to allow pursuing car to run closer to their rival. The double diffuser has been banned for this season, which may help to address the problem.

Where overtaking does take place, it is usually when one driver has a straight-line speed advantage over the car in front. This can be achieved by a process known as slip-streaming, where the driver behind eliminates some of the drag on the front of his car by closely following another. With less drag, the chasing driver can build up speed behind his rival and then, when he pulls out alongside, although both drivers are now subjected to the same amount of force, the slip-streamer has more momentum, and can power past his rival. At tracks with long straights, such as Malaysia, China and Monza, those drivers with Mercedes engines – generally considered the most powerful on the grid – found it reasonably easy to get past their rivals. With more horsepower available to them and, with extra help from a slip-stream, they would have their nose ahead at the end of the straight, and could take the position into the corner.

This is why KERS (Kinetic Energy Recovery System), introduced in 2009, helped with overtaking. The driver had a button on the steering wheel which, when pressed, would use energy stored under braking to give the engine a power boost, resulting in a few extra horsepower on the straights. However, the system was expensive to develop, and there was a large weight penalty for any driver using it. McLaren were the only team to consistently use it, Ferrari chose to deploy it at selected tracks, Renault had a go, and everybody else decided it was more trouble than it was worth.

Of course, if everybody used KERS, which was tightly regulated in terms of the amount of boost and the length of time it could be deployed each lap, then there would be little or no benefit to the driver doing the overtaking, as the driver defending the position could press their own button, and the boosts of the squabbling pair would be cancelled out.

The new-for-2011 driver-adjustable rear wings basically consist of a flap on the rear-wing which is closed for most of the lap, providing the car with the most downforce. When a driver presses a button on his steering wheel, the flap lifts. This allows air through the wing, decreasing its effectiveness, and improving the straight-line speed of the car.

So far, this sounds similar to last season's F-duct, the device developed first by McLaren. It allowed the driver to direct air onto the rear wing when required, spoiling its aerodynamic effect, and increasing the straight line speed of the car. Other teams developed similar devices, McLaren's advantage was lost, and the FIA have banned this ingenious concept for 2011.

The driver-adjustable rear wing differs crucially in that the driver can only use the device when race control allows them. The regulations will allow rear-wing adjustments at any time during practice and qualifying, so drivers can use the device on every straight, maximising their lap time. This will also allow their engineers to set the correct gear ratios to take advantage of the device, and not have the rev limiter bouncing off the 18,000 limit when the flap is raised.

So far it all sounds pretty straightforward. But when the race starts, the regulations get more complex, and the opportunities for a driver to use this device becomes much more limited. The device may not be used at all during the first two laps of a race (for safety reasons) and after that it can only be used 'for the sole purpose of improving overtaking opportunities'.

Race Control will alert the driver as to when he can use the device with a light in the cockpit, similar to the blue flag lights currently used to warn backmarkers of a faster car approaching. The rear-wing adjustment will only be enabled when a car is less than a second behind another, and only at predetermined positions around the track. The driver can then decide whether or not to activate the system by pressing a button on his steering wheel. The rear-wing will return to its closed position the next time the driver touches his brake pedal (i.e. at the next corner).

Of course, if a driver can just sail past an opponent easily, the skill is taken out of overtaking. The overtaken driver will just bide his time until the next straight, where he can use exactly the same method to re-take the position. Cars would change places four or five times a lap, and it would be, quite frankly, ridiculous. However, the FIA will, apparently, carefully choose the point on a straight at which the driver can adjust his rear-wing, to ensure that overtaking remains a challenge.

And how will the watching audience know whether the driver is using the system in an overtaking manoeuvre? One expects that the on-board graphics on the television pictures – those that show the revs, gears and speed of a particular driver – will also now show when the system can be enabled and whether the driver is using it or not, in a similar way to how it showed KERS usage back in 2009. Fans at the track, however, may be completely oblivious to how the system is being used.

This new device is an interesting idea, but could have some potential pit falls. The real test of the system will be ensuring that overtaking still remains challenging, and that a skilful driver still has more chance of overtaking than one who is less able. The complexity of it, and the fact that it seems a bit too artificial in the way that it engineers overtaking opportunities, means it will have its critics.

There have been many attempts over recent years to improve overtaking in Formula 1 without much success. Will the driver-adjustable rear wings be the silver bullet that solves the problem?