A fundamental analysis of the handling characteristics of Winston Cup race cars

The NASCAR Winston Cup Racing Series has achieved unprecedented success and growth in the last ten years, becoming the premier automobile racing series in the country. With increased demands on the teams due to the large number of races and limitations on testing imposed by the sanctioning body, there is a need for advanced engineering tools to aid in chassis setup. This work describes methodologies and simulation tools that were developed to predict the handling characteristics of Winston Cup racecars allowing setup parameters to be evaluated in a virtual environment.; In the initial phase of the project, a simulation model was developed to predict the kinematic responses of the racecar. Associated methodologies to characterize the geometric properties of the chassis and suspension components were developed. The kinematic model allows the user to assemble a “virtual” racecar from its constituent parts and apply a user defined setup specification. Using the kinematic model as a foundation, a steady state handling model was created allowing the evaluation of tire loads, chassis attitude and limit performance on banked race tracks. The steady state model is not based on the roll axis concept. Its governing equations are derived considering the actual three dimensional geometry of the suspension and chassis.; Comprehensive studies were then performed to ascertain the effects of typical setup parameters on the limit handling characteristics of the racecar. Situations of combined cornering (longitudinal and lateral accelerations) were investigated for different levels of track banking angle. The parameter studies were divided into three major categories: (1) parameters that affect tire normal loads or chassis attitude; (2) parameters that affect the orientation of the tire; and (3) parameters that affect aerodynamic performance. Additionally, simulations were performed to evaluate the effects of the various setup parameters on a specific race track. The track chosen for study was the Indianapolis Motor Speedway. These simulations, commonly referred to as “lap time simulations,” provide a means to evaluate the performance of the vehicle and setup on a specific race track.