The Effects of Wing Aerodynamics on Race Vehicle Performance

An analytical study is presented to determine the effects of wing aerodynamics on various racecar performance characteristics and on lap times for different types of tracks. The North Carolina State University (NCSU) Formula SAE car is used as the racing vehicle for this study. The study integrates design and analysis methods for airfoils and wings with performance-simulation methods for the racecar. Various performance parameters are considered to study in detail the effects on different portions of the track.

A single wing is first used to examine the effects of aerodynamic downforce on car performance without considerations of the fore-and-aft location of the aerodynamic center of pressure. Subsequently a traditional dual-wing setup with a front and a rear wing is used to study the effect of downforce while satisfying a constraint on the location of the aerodynamic center of pressure. Three airfoils with systematic changes to the camber are used as candidates for the section shapes. Results are first presented for the racecar performance with the three airfoils during cornering, straight-line braking, and straight-line acceleration conditions. The effect on lap times for different track geometries is then presented for the single-wing configuration followed by the dual-wing configuration. The results for the single-wing case show that for a majority of the cases examined, the best performance occurs at the maximum-lift condition of the wing, indicating that the design goal is one of maximizing wing downforce. For a few track geometries, however, the results indicate that the optimum performance occurs when the wing is operating at less than the maximum-downforce condition. The loss in performance due to increase in drag associated with increasing the downforce beyond this optimum value outweighs the benefits of the additional downforce. The results for the dual-wing setup show that the range of possible operating points for the rear wing is considerably reduced by the constraint that the front-wing downforce has to balance the rear-wing downforce. The approach is suitable for the determination of the most-suitable wing for a given track. While the results in the paper focus on the NCSU Formula SAE car, the methods, results and discussion are applicable to a variety of racing vehicles with wings.