BATTLING AGAINST THE ELEMENTS

To increase safety in Formula 1 even further, the cars’ wings were given added support before this season. However, the new regulations have not affected the significance of aerodynamics on performance on the track in any way. On the contrary, the challenge for the engineers is now even greater. Frank Dernie from WilliamsF1 says: "They had to find solutions quickly to compensate for the lost downforce. It was a tough job."

In the tough struggle for crucial seconds in Formula 1, aerodynamics plays an even more important role than the tyres and the engine. A fast car is more than ever a question of the right set-up: there are 20 different possible settings for the rear wing and a further 100 for the front wing. While the engine power used to be the crucial factor for the performance of the cars, the key aerodynamic data are nowadays almost more valuable than the engine horsepower.

Aerodynamics is primarily so important because of the downforce that presses the car on to the track and so permits short braking distances and high cornering speeds. Experts estimate that 80% of the car’s grip is generated by the down-force and only 20% by the tyres. The search for more downforce has become the driving force behind entire departments at the teams. But downforce is not everything: as so often in Formula 1, the key is to find the best compromise – in this case, between the greatest possible downforce and the lowest possible air resistance. A Gordian knot that is not easy to cut. There is no ideal set-up suited to every track, and certainly not to every section of a track. So, in simplified terms, the secret for success is to get closer to the ideal than the competition.

The basic principle of aerodynamic performance in the construction of race cars is comparatively simple. It works in the same way as on an aeroplane, but in reverse. The surfaces of the wings have a different shape on the underside, so the air flows faster underneath, where it has a greater distance to travel. This creates a vacuum which provides the required grip and high cornering speeds and allows a Formula 1 car to stay perfectly on line even under centrifugal forces of 4G, whereas a passenger car begins to slide at just 1G, even if it has a sport-type running gear. So the great art of aerodynamics is not only to allow excellent performance, but also to improve safety.

The rear wing generates a good third of the total downforce, but at the same time it also causes the greatest air resistance. As a result, it is subjected to the most changes from race to race, in the search for the perfect blend of downforce and speed.

The following generally applies: on city tracks or tracks with many tight corners, the wing elements are set steeply, whereas they are set flat on tracks with long straights and fast corners, as now at the Italian Grand Prix in Monza, to gain the highest possible speed. Twenty-five percent of the downforce is generated by the front wing, but not if the car is driving immediately behind one of its rivals. This is because the rear of the rival car causes turbulence – so-called ‘dirty air’ – which reduces the downforce created by the front wing on the car behind another car to just about 10%. This is one of the main reasons why it is so hard to overtake on many Formula 1 tracks. The diffuser also contributes to the aerodynamic efficiency, as its tunnel and ducts on the underside of the rear lead diagonally upwards like a ramp and guide the incoming air to create the largest possible suction effect. Up to 40% of the total downforce is generated by the air accelerator on the underbody.

The vehicle developers of passenger cars are also focusing on the underbody. Large-scale trim parts contribute to the aerodynamic efficiency: they reduce the air-flow resistance and the undesirable lift. While Formula 1 cars are pressed down on to the track, passenger cars tend to develop lift forces when driving quickly. "The smoother the underbody, the faster the air can flow over the underside of the vehicle," explains Dr. Christoph Lauterwasser from the Allianz Center for Technology (AZT). "This creates a vacuum like in Formula 1, which can help to keep the lift of the entire vehicle to a minimum. This provides better driving stability at relatively high speeds."

As a small air deflector shield between the front wheel and the sidepods can, in some circumstances, provide more speed than a couple of extra horsepower, aerodynamics is one of the most important factors in the design of a Formula 1 car. Only those teams that have their own wind tunnel can keep up with the extremely fast development. The cost? Around 45 million euros. The engineers use these installations to test not only the shape and setting of the aerodynamic parts designed on the computer, but also, for instance, the sensitivity of the car to a modified incoming air flow, perhaps due to nodding-style movements or a side wind. The attraction for the defenders of the pure science of airflow is enormous – they spend around 8,000up to 13,000 hours a year in the wind tunnels.

The service range of a modern wind tunnel is also impressive: the WilliamsF1 tunnel at the company headquarters in Grove, where the fan is driven by a 60-tonne, 4,000-HP engine, can even simulate hurricanes.

 

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