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This paper details the aerodynamic development of the University of Maryland's Pride of Maryland solar powered race car. This vehicle was built for the General Motors Sunrayce U.S.A., held in July of 1990. Two 3/8 scale models were built and tested in the university's wind tunnel. In addition, computational fluid dynamics and full scale testing were used to verify the design. Race experience further proved the worthiness of the design. Conclusions were drawn between the 3/8 scale model test results and the full scale results.

There is little information in the technical literature about the dependence of drag coefficient, CD, on aspect ratio (height/width) for car and truck aerodynamics. Some of the information suggests that CD should increase with aspect ratio as the flow over the body becomes more two dimensional. Recent tests of candidate shapes for a commercial van with various roof heights suggested the opposite is true; the taller vans had lower drag coefficients. This report discusses the results of several experimental investigations to examine this relationship. Scale model and production drag measurements of commercial vans are presented along with drag measurements of simple shapes. The shapes consisted of eight radiused rectangular boxes of constant length and frontal area, but with different height/width ratios. The effects of underbody roughness and bumper presence were evaluated and are discussed.