Influences along the aerodynamic pathway

Influences along the aerodynamic pathway

Like anything else in the trucking world, the ongoing development of trailer aerodynamic systems benefits from a wide array of early influences, everything from hard-earned day-to-day TL operational experience to the musings of a freshly minted engineering school graduate.

“It is an absolute fact that my experience in the freight world has helped me assist in the development of our products, beginning when Aerofficient was referred to U.S. Xpress for consideration as a supplier,” explains Marty Fletcher, formerly director of training, equipment research and development for U.S. Xpress Enterprises and now director of customer service and product development for trailer side fairing maker Aerofficient.

Fletcher had already determined through rigorous testing at the Chattanooga, TN-based TL carrier that keeping the trailer tandem gap closed, regardless of the tandem axle position, is critical to maintaining fuel-economy savings for side fairings.

“This could only be accomplished with some form of a sliding panel, which Aerofficient had already been working on,” he says. Based on his experience, the company’s “sliding side fairing” evolved so it could accommodate any tire design, including wide base singles, on a trailer’s tandem axle.

Then there’s Sean Graham, who founded Freight Wing Inc. in 2003 right after finishing up his degree in mechanical engineering at Penn State University. As he drove west to pursue graduate work in wind tunnel engineering, Graham couldn’t believe what he saw along the endless stretches of highways—the contrast between the blunt and boxy shape of all freight trailers and the sleek and round-edged shape of the tractors that pulled them.

Mile after long mile, passing tractor-trailer after tractortrailer, he grew more and more convinced that there had to be a way to improve the aerodynamic footprint of trailers to match that of their tractor counterparts, thus reducing drag and fuel consumption.

Of course, Graham discovered there were already hundreds of patents for a huge range of aerodynamic trailer innovations. “It’s a big list of very expensive attempts to solve this problem,” he says, but that didn’t deter him. He remained convinced he could develop a cost-effective solution.

After winning a $75,000 grant from the Dept. of Energy to conduct computer simulations confirming drag improvement and fuel savings, he set out at first to develop a “boat tail” for trailers but switched to side fairings based on his findings.

“We expected the boat tail to perform the best, but the belly fairing came out on top,” he explains, pointing to early results of three fairing prototypes tested at the Transportation Research Center in East Liberty, OH, using SAE and TMC fuel economy measurements. Fuel economy improvements by type were belly fairing, 4%; gap fairing, 2%; and boat tail, 1%.

“It just goes to show what you think is the solution at the start isn’t necessarily where you finally end up,” Graham notes.

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