Wings a matter of adjustment

During the course of Formula 1 history, the designers have attempted to mount parts to almost every part of the car, the intention being to provide greater downforce (the force with which Formula 1 cars are pushed onto the road). Some of them proved to be unsuitable, others were banned by the International Automobile Federation (FIA) for safety reasons, for example the X-wings mounted to the sidepods. Today, apart from the wings, diffusers and spoilers are also used as aerodynamic aids.

Although roughly one quarter of the downforce is generated by the front wing, this is only the case when the car is not directly behind another one on the track. In such an instance, the turbulence caused by the car in front, the so-called ‘dirty air’, unbalances the car following behind, causing its road-holding to become less stable. Here the downforce generated by the front wing drops to 10 per cent, which is the main reason why overtaking has become so difficult in Formula 1. A Formula 1 car’s centre of gravity is toward the rear, therefore, the front wing has to compensate for the lack of weight on the front axle. Apart from this it is also responsible for directing the air stream with as little turbulence as possible, ensuring an optimum air flow to other aerodynamic components. This is backed up by the so-called winglets mounted on the sides of the wings.

Movable front and rear wings are used to achieve an ideal combination of downforce and top speed for each individual circuit. The following generally applies: on street circuits or circuits with many corners, the wing elements are given a steep setting; on a circuit such as in Barcelona however, the wings are set to a more horizontal position to enable high speeds to be achieved. “The correct wing set-up is always a circuit-specific compromise. If they are set too steeply, our top speed on the straights will be lower. If they’re too flat, we end up with less downforce, something we need in the corners,” says Gavin Fisher, Chief Designer at WilliamsF1.

When it comes to designing an F1 car, the aerodynamicists have the largest budget of all the team’s development departments. The wings are designed – as is the rest of the car – on the computer with the aid of CAD (Computer Aided Design) and CFD (Computational Fluid Dynamics): this enables the designers to simulate the air stream for each individual part. Traction, coupled with wind speed and direction, are factors which also have to be taken into consideration when designing the wings. The finished wings are then tested by the team in the wind tunnel. However, that still does not guarantee arriving at an ideal solution – this is because constantly changing conditions such as those prevalent in Barcelona cannot be run through a simulation – yet.

In passenger cars, the spoiler and wings only play a subordinate role in comparison to the design of the chassis as a whole. Passenger cars are not developed in order to achieve as high a speed as possible nor to establish new boundaries of stability; here other factors are more important: safety, driveability, road-holding, comfort and fuel consumption.

“The extreme cornering speeds and deceleration when braking in Formula 1 would not be conceivable without the massive aerodynamic downforce generated by the wings. Although passenger cars never actually come close to this area,” says Dr. Christoph Lauterwasser from the Allianz Centre for Technology, “aerodynamic body styling parts are also used in their production. They particularly play a role in terms of safety and stability; aerodynamic styling parts can – when set up properly – enhance driving stability at higher speeds.”

The factor of fuel consumption, in particular, is an important reason for not frequently using wings in passenger cars: they increase drag and fuel consumption. All the same: for a mid-size passenger car the share of drag on overall road resistance when driving at a speed of 100kph is 75 per cent. Wings and spoilers are usually factory-mounted to sports cars, where, they enable a car to hold course even at high speeds. In the meantime, however, in order to achieve an economic driving style, wings are now being used which automatically extend when the car has reached a predetermined speed.