Image: Georgia Institute of Technology

The influence of aerodynamic engineering is plainly seen in the designs of many passenger cars. Rounded, sleek curves on some models serve to reduce drag and improve efficiency in much the same way as they would on airplanes. And now engineers at the Georgia Tech Research Institute are trying to apply similar lessons to tractor trailors. They hope that by making these big rigs more streamlined, they can not only raise fuel savings but also make them easier to control and safer.

Bob Englar and his team have come up with an 18-wheeler's rendition of a circulation control flight system, which Englar and his associates developed for aircraft in the 1970s and 1980s. This pneumatic system would work by blowing compressed air from slots located on all sides of the truck. Air flowing over the trailer's curved topped surfaces would provide lift, as it would over a wing, relieving some 15 percent of the vehicle's weight from the tires and limiting wear. Air blown from the bottom would have the opposite effect, producing a downward force to assist in braking and traction. And air pushed out from either side would counter crosswinds, helping to fight sway and jackknifing.

Directing the air would happen automatically as needed, Englar says. Currently his group is testing the system on small models at the Georgia Tech Research Institute's wind tunnel (above). The results look promising. They expect that much of the technology could be retrofitted onto the existing truck fleet, and major manufacturers have gotten involved to ensure practicality. "There would be both fuel savings and a safety payoff, so the synergies are really quite interesting," notes Victor Suski, senior automotive engineer with the American Trucking Association. "Everybody who has heard about this intuitively feels there is great potential here."