An Approximate Lap Time Minimization Based on Indy Style Racing Car Geometry

At the Indianapolis 500, racing teams expend a great deal of effort to shave hundredths of seconds off of lap times. This paper concerns the use of a simple model to provide an optimal combination of design parameters, such as wing induced downforce, available engine power, tire slip angle characteristics and aerodynamic drag which will give a minimum lap time. The model is based upon experimental data mainly from the 1988 racing season. (This data is presented in its entirety.) Analysis indicates that the limiting factor of fast lap times is the allowable tire slip angle. Based upon this model a minimum lap time of 40.8 seconds is calculated which corresponds to a speed of 354.90 km/hr (220.57 MPH). In an attempt to further characterize this optimum point, some parameter studies are performed which yield design curves illustrating the car's sensitivity with respect to changes in vehicle mass, engine power, air density and minimum aerodynamic drag.