Audi has just released details on the high-tech wind tunnel used to test the new R18 TDI race car compete in the upcoming 24 hour Le Mans endurance race. The R18 features an enclosed cockpit, something Audi hasn’t done since the R8C that raced in the 1999 Le Mans.
Carmakers including Audi are increasingly switching to lower displacement engines to overcome fuel economy and emissions obstacles set by lawmakers (the S4, for example) and the race world is not immune to the trend. In order to meet new FIA regulations, Audi downsized the R18’s engine to a 3.7-liter turbo-diesel V6, which is significantly smaller than the 5.5-liter TDI V-10 used in last year’s R15 race car. To combat the loss in horsepower, Audi focused its efforts on improved aerodynamic and chose to make the R18 a closed race car. The racing development team didn’t have to search far to test the new race car in an advanced wind tunnel. They turned to colleagues over in the production side for use of the new climatic wind tunnel at the Audi Wind Tunnel Center in Ingolstadt. It’s the first time a racecar has used the facility since it opened in 2008.
In addition to producing wind speeds of up to 300 kilometers an hour (186 mph), the climatic wind tunnel allows engineers to adjust the temperature between an icy-cold minus 25 degrees Celsius to a toasty 55 degrees Celsius (minus 13 to 131 degrees Fahrenheit). And for true real-world testing, the tunnel can add weather and road hazards into the mix, such as rain, sand and stones. Engineers use all these elements to test the airflow, windscreen and the windscreen wiper. "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."
The extensive airflow testing not only helped improve aerodynamics, but it also allowed engineers to regulate the cockpit temperature and forego the use of a weight-busting air-conditioner. Additional help comes from a special film that helps block out heat from the sun. Regulations have set the maximum cockpit temperature at 32 C (90 F) when the outside temperature is 25 C (77 F). Audi says the cockpit should stay within the allowed temperature range keeping the driver nice and comfy come race day.