A Summary of NASA Dryden's Truck Aerodynamic Reasarch

A combination of subscale wind tunnel model tests and full-scale coast-down and highway fuel consumption tests have been conducted on baseline and low-drag tractor-trailer configurations. Fuel savings calculated for the low-drag configuration, based on the model drag data or the full-scale drag data, correlate quite well with fuel savings obtained from over-the-road tests at highway speeds. Sub-scale drag tests for flow-vane and boattail devices provided drag reductions of about 48 percent and 15 percent, respectively, for bus- or motor-home-type vehicles. Full-scale boattail drag data are also presented.