Crosswind Response and Stability of Car Plus Utility Trailer Combinations

The results of a wind tunnel study and a computer simulation are used to determine the effects of aerodynamics on the lateral-directional stability and crosswind response of passenger car/utility trailer combinations. Single and tandem axle utility trailer configurations, with and without drag reducing add-on aerodynamic fairings, were considered with both sedan and station wagon tow cars. Results showed that including aerodynamic terms in the six degree of freedom model reduces the trailer tow angle stability and damping by a few percent. More importantly, the random crosswind response, expressed in terms of tow car yaw velocity, was amplified about 20 to 30 percent when a drag reducing device was added to the trailer.