Freightliner LLC has opened North America’s only full-scale wind tunnel built solely for testing heavy and medium-duty trucks.

The 12,000-square-foot facility, located near the company’s Portland, Ore., headquarters, was designed by Freightliner Engineering with help from the Freightliner Vehicle Systems Technology Center, NASA Ames Research Center, Portland State University and the Mercedes-Benz Trucks analysis team.
"We utilized the best aerodynamic engineering talent and latest computer-aided design tools both inside and outside of DaimlerChrysler to design a unique facility," said Michael von Mayenburg, senior vice president, engineering and technology. "We look forward to putting this facility to work to further enhance the aerodynamics of vehicles produced by Freightliner LLC brands."
Freightliner built its own tunnel because the cost of renting one is $30,000 to $100,000 an hour, he said. It will also save the time and expense of shipping trucks to Germany to be tested in DaimlerChrysler's wind tunnel. Von Mayenburg declined to say exactly what it cost, but pegged it at one-tenth the price of a typical automotive-type tunnel if built today."
This was accomplished by choosing a pass-through design rather than an expensive closed-loop type, and by carefully designing walls so they parallel the flow of air across a truck, which allowed a smaller and less costly structure. The new tunnel is full-scale because "there are limits on what you can learn from partial-scale tunnels," he said.
Von Mayenburg also said one of the company’s goals is to reduce drag 15% and cut fuel consumption 5% on its next generation highway tractors, due out in 2007. The tunnel will be used to test upcoming new products and to refine aerodynamics on existing Freightliner, Western Star and Sterling trucks.
In addition to air flow over the hood, under the vehicle and past windows and mirrors, engineers will study how air flow affects engine cooling and splash and spray generation. Smooth air flow also cuts noise and the buildup of dirt and grime on trucks, Von Mayenburg said.
Sensors provide information regarding wind load and surface pressures on the vehicle as a whole and for specific parts. Non-toxic fog provides airflow visualization and qualitative data regarding localized airflow. A sophisticated instrumentation system is used to operate the wind tunnel, monitor ambient conditions and record aerodynamic data.
At the opening ceremony, Oregon’s Gov. Ted Kulongoski, who said he once drove trucks for a living, started the 10 industrial blower fans that draw air through the wind tunnel. The fans, which are synchronized by computer, together produce 2,500 horsepower and move more than 2.5 million cubic feet per minute of air, allowing for test section wind speeds of over 60 mph.