The Importance of Aero

by James Menzies

PORTLAND, Ore. – With fluctuating diesel prices and more fuel-thirsty engines on the road today, truck aerodynamics are more important than ever before.

Freightliner has acknowledged this by constructing a $5 million state-of-the-art wind tunnel at its Portland research facilities, which will allow the truck maker to fine-tune airflow over its entire product line.

Previously, Freightliner had to shell out big bucks to rent off-site wind tunnel facilities while also relying on scale-model testing. Matt Markstaller of Freightliner told Truck News that wasn’t enough.

“There’s a lack of any other suitable facilities in the United States to do (what we needed to do),” said Markstaller.

“There are some you could argue are suitable, but they’re pretty expensive so we wanted to be able to expand the scale of what we do, and with the development we want to do renting is really cost-prohibitive.

“We wanted to come up with something we could have on-site and although it has some up-front costs to it we are able to run it economically.”

The 12,000-sq. ft. facility will be running one or two shifts per day with four to six people manning the controls. It consists of the wind tunnel itself, a control room and support shop. Ten industrial blower fans with a combined strength of 2,500 h.p. can create more than 2.5 million cubic feet per minute of airflow. That’s equivalent to wind speeds of more than 65 mph.

While computers are used to read most of the data, non-toxic fog can also be dispensed which gives a visual sense of how air moves over the vehicle.

“We will measure lots of different parameters on the computer so we know exactly quantitatively what differences we’re making but the fog is for visualizing airflow over different parts of the rig and it really helps us figure out qualitatively what direction we need to go,” Markstaller explained.

“You can measure what drag is but unless you can see what the flow is, it’s hard to know what to do to improve it.”

Of particular interest to Freightliner is how the air flows over the hood, under the vehicle and past the windows and mirrors.

And with higher engine temperatures resulting from the new generation of environmentally friendly diesel engines the company will also be examining how airflow affects engine cooling and splash and spray generation.

Freightliner had some help developing the high-tech wind tunnel from the likes of the NASA Ames Research Center, Portland State University and the Mercedes-Benz Trucks analysis team.

“We used 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 of engineering and technology with Freightliner.

“We look forward to putting this facility to work to further enhance the aerodynamics of vehicles produced by Freightliner brands.”

Markstaller said the new wind tunnel is a one-of-a-kind facility that better serves the needs of Freightliner than even parent company DaimlerChrysler’s tunnel in Stuttgart, Germany.

“The one in Stuttgart is kind of an all-purpose one,” Markstaller said.

“It worked really well for cars and it works for trucks as well but the facility we have built is for trucks only. It’s really set up to do what we want it to do all the time.”

That’s not to say that DaimlerChrysler’s own experience with wind tunnels on the car segment of its business won’t prove invaluable.

“There are methodologies that the car guys have developed over the past 30 years that we’ll be able to take advantage of and apply right away,” Markstaller said.

While customers can expect more aerodynamic and fuel-efficient vehicles from Freightliner as a result of this investment, they shouldn’t expect any radical new designs to begin surfacing immediately, he warned.

“Performance-wise the trucks will differ quite a bit but styling-wise we’re still sensitive to the market,” he said.

“We expect to be able to integrate some good improvements while maintaining the styling direction that we want.”

Currently, the company is putting its existing product line under the microscope to see what enhancements can be made to improve airflow.

Any new truck the manufacturer develops will also spend its share of time in the tunnel.

Like kids with a new toy, Markstaller predicted Freightliner engineers will be getting plenty of use out of the new tunnel now and in the foreseeable future.

“We’re really excited to have it and we think it will help us maintain our position at the forefront of the technology curve with heavy trucks but it is really going to help us advance that much further because this is one discreet tool that nobody else has,” he said.

“We have some knowledge now that we’ve never had before and tools and methodologies to make aerodynamics better and contribute to fuel economy.”

Of course, that will also win the manufacturer some appreciation from the environmental types as well.

“If you can burn less fuel than you get less particulates by the same margin,” he pointed out.

The new facility was officially opened amid much fanfare in Portland on Apr. 13. Oregon Governor Ted Kulongoski; U.S. Representative David Wu; and Portland Mayor Vera Katz attended the opening ceremony.


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