Methodology for the design of an aerodynamic package for a formula SAE vehicle

Recent changes to the rules regarding aerodynamics within Formula SAE, combined with faster circuits at the European FSAE events, have made the implementation of aerodynamic devices, to add down-force, a more relevant topic. As with any race series it is essential that a detailed analysis is completed to establish the costs and benefits of including an aerodynamic package on the vehicle. The aim of the work reported here was to create a methodology that would fully evaluate all aspects of the package and conclude with an estimate of the likely gain in points at a typical FSAE event. The paper limits the analysis to a front and rear wing combination, but the approach taken can be applied to more complex aerodynamic packages. An initial wind tunnel investigation of the potential flow interactions between the driver's helmet and rear wing using a multi-hole pressure probe is reported and the data used in a two-dimensional CFD calculation to provide an accurate prediction of the likely down-force from the wing package. The chosen configurations are tested in a comprehensive wind tunnel program and a map of potential setups generated. The potential aerodynamic configurations are assessed in both quasi-static and dynamic handling analysis to demonstrate the effects of aerodynamic lift, lift distribution, aerodynamic drag, and the effect of additional weight, weight distribution and height of the center of gravity. The paper includes a description of the wind tunnel model and scaling considerations and a description of the handling model and the lap simulation methods. The results shows that a simple front and rear wing combination, providing relative low down-force (1000N at 110kph on a vehicle of 280kg, including driver), gives an improvement in performance equating to a gain of approximately 40 points during the event. The largest improvements are seen during the autocross and endurance events. This gain is considered sufficient to justify the inclusion of the package on the vehicle. Copyright © 2014 SAE International.