Allianz F1 Safety Focus - Winds of Change

The heart of any modern wind tunnel is the test section. The vehicle model is placed on a steel conveyor belt that simulates the road. Using fully synchronised multi-axle model management, the technicians are able to examine virtually all the factors that might affect a race car on the track. Dr Antonia Terzi, WilliamsF1's Chief Aerodynamics Technician, believes that this results in “an increase in precision by 30 percent”. Another very impressive feature is the giant fan with its carbon rotor blades, which achieve speeds of approximately 600 revolutions per minute.

Powered by a 60-ton, 3-megawatt (4,000HP) engine, it generates tornado-like wind speeds that blow a calm air mass of nine tons into the test section, at up to 300 kilometres per hour, in the space of only 30 seconds. The conveyor belt simulates driving the car because the asphalt also creates eddies that influence the aerodynamics.

During the tests in the wind tunnel, the aerodynamics technicians are interested in three values: downforce, drag and pitch sensitivity. Greater downforce increases the vehicle’s cornering speed but should ideally be achieved without increasing drag, which in turn reduces the top speed. Pitch sensitivity defines how strongly the car is affected by aerodynamic changes such as those created by uneven surfaces that continuously alter the distance of the wings and underbody to the surface of the track.

Newer wind tunnels, like WilliamsF1’s, have the advantage of facilitating tests on one-to-one scale vehicles. Many wind tunnels allow testing only with 50- or 60-percent sized models that are unsuitable for the exact simulation of the airflow through certain vehicle components such as wheel carriers or rims. Another method of testing is to use two smaller models, one behind the other, thus measuring the airflow created in the slipstream. The height and position of the models can be altered at any time from outside via remote control – with a precision of 0.01 millimetres. The wheels, accounting for roughly one-third of the entire vehicle’s air resistance, are tightly fitted into the test installation on struts.

To stay ahead in the tough competition on the global market, all the major car manufacturers run their own wind tunnels. “Although it is becoming possible, with the increasing realism of numeric flow mechanics, to calculate more and more characteristics by computer, the experimental examination and refinement in the wind tunnel will remain indispensable in the foreseeable future,” says Dr. Christoph Lauterwasser of the Allianz Centre for Technology. “The main issue with passenger cars is the optimisation of air resistance and thus fuel consumption, but beyond that many other questions, such as the minimisation of wind noises, for instance, are also researched.”

How quickly aerodynamic improvements can be implemented in Formula 1 thanks to the wind tunnel can be seen in the new development stage of the Williams FW26. On the Monday after the Monaco Grand Prix, WilliamsF1 Technical Director Sam Michael gave his engineers the task of carrying out extensive modifications on several parts, including the sidepods, ventilation inlets, radiators, engine cover, exhaust pipe guideway, winglets, flip-ups, underbody, rear wings, tie rods and front-axle spare wings. Only four races later, at the French Grand Prix, the comprehensively enhanced race car was ready. Without the wind tunnel, it would only have been possible to achieve this by the beginning of the next season.

For these modifications alone WilliamsF1’s wind tunnel team worked for approximately 500 hours. All in all, according to estimates by experts, the aerodynamics technicians of the Formula 1 teams spend up to 8,000 hours a year in the wind tunnels. To make optimal use of the systems it is not uncommon for work to proceed in two, sometimes even three, shifts.

“Our wind tunnel provides great possibilities for the optimisation of our car’s performance,” says Gavin Fisher. “It would be a grave mistake not to use these possibilities to the full.”