With less than month until this year's 24 Hours of Le Mans Audi Sport Team Joest have taken advantage of the climatic wind tunnel at their Ingolstadt base, working with a full scale Audi R18 TDI.
The wind tunnel is able to generate temperatures of between -25°C and 55°C and wind speeds of up to 300km/h. In other words the perfect location for a test ahead of June's La Sarthe encounter.
Recent work has focussed on three areas – cooling and ventilation of the R18's enclosed cockpit, the windscreen and the car's single arm windscreen wiper.
“This subject is not as trivial as it would perhaps appear,” says Dr. Martin Mühlmeier of the wiper. “We do indeed have experience from the DTM. However, the windscreen wiper is hardly ever used here. Also, a DTM car reaches 250 km/h and not 330. The demands on the windscreen wiper are considerably higher at Le Mans.”
The work in the wind tunnel has also helped Audi overcome some of the problems associated with closed coupe cars, the manufacturer running a closed cockpit car for the first time the R8C. This includes the windscreen, curved in two directions (unlike a production car's screen) and made of plastic. Audi cite the work in the wind tunnel as helping the to develop a three tier plan for cleaning the windscreen, depending on the severity and nature of the soiling.
Perhaps the most obvious problem that drivers and team face with a closed cockpit car is the potential problem with temperature in the cockpit. Auto Club de l'Ouest regulations state that the temperature inside the car cannot exceed 32°C when the outside temperature is less that 25°C.
In an effort to comply Audi use reflective film on the roof of the cockpit, and the value of this was shown in the climatic wind tunnel. The tests also showed than the R18 could rely on cockpit ventiliation alone to maintain the correct cockpit conditions, rather than Audi having to run air conditioning, saving weight and power – the engineers understandably happy to rule out the use of the system for the June 11-12 race.
“We can rely on the findings from the climatic wind tunnel – it's a great benefit to have such an extremely high quality tool available,” says Christopher Reinke, Technical Project Leader for the R18 TDI. “The results of everything which we have tested in the climatic wind tunnel up to now have been confirmed during testing on the race track.”
