The Effects of End Plates on Downforce in Yaw

Achieving maximum downforce during cornering is critical in the aerodynamic design of a race car. During cornering, all race cars will be at some angle of yaw relative to the vehicle velocity vector, and in certain forms of racing the yaw angle can be large. For this reason it is important to take into consideration the effect of yaw on the aerodynamic characteristics of the vehicle. Most aerodynamic elements on vehicles have been examined in some detail in straight ahead motion. However, an element such as a wing/end plate combination optimized for straight forward motion may not perform well under yaw conditions. This effect may substantially diminish the aerodynamic advantage for race cars in high yaw, such as those raced at the Pike's Peak Hill Climb.

As a part of a comprehensive research program relating to optimized aerodynamics at high yaw angles, the effect of end plate design on lift and drag of a rear wing in free stream is being considered. Six different rear wing end plate configurations were analyzed using computational fluid dynamics (CFD) to find the effect of end plates on rear wing downforce in yaw and in straight line motion. The profiles of the end plates were varied to change the air flow over the wing during yaw, with a focus on reducing lift losses in yaw. The resulting data show the effects of traditional rectangular end plates casting a shadow on the wing causing a reduction in lift during cornering.