High-Downforce Airfoil Design for Motorsports 2012-01-1168

Using a combination of inverse airfoil design techniques, rapid interactive analysis methods, detailed computational fluid dynamics (CFD) and wind tunnel testing, aft loading of an airfoil has been explored as a design direction for high-downforce airfoils for race car rear wing applications while ensuring performance sustainability across a wide angle-of-attack operating range. Unlike in aircraft oriented high-lift airfoil designs, pitching moment constraints can be circumvented for race vehicle wing designs and this allows for further design freedom in the quest for downforce. The PROFOIL inverse design code was used to design a candidate airfoil exhibiting downforce maximized using aft loading at low Reynolds numbers. The resulting airfoil has a maximum lift coefficient of 2.5 at a designed Reynolds number of 300,000 and shows that aft loading on an airfoil is conducive to high-downforce requirements and is a favorable design direction when considering airfoils for race car wing applications. Comparisons have been made with airfoils representative of the high-lift design philosophies of Liebeck, Wortmann and Selig.