Drag Forces Experienced By Two, Full-scale Vehicles At Close Spacing

The present study aims to document the drag reduction for a two-vehicle platoon by operating two full-scale Ford Windstar vans in tandem on a desert lakebed. Drag forces are measured with the aid of a special tow bar force measuring system designed and manufactured at USC. The testing procedure consists of a smooth acceleration, followed by a smooth deceleration of the platoon. Data collected during acceleration allows the calculation of the drag force on the trail-vehicle, while data collected during deceleration is used to calculate the drag on the lead vehicle. Results from the full-scale tests show that the drag behaviors for the two vans are in general agreement with the earlier conclusions drawn from the wind tunnel tests--namely, both vans experience substantial drag savings at spacings of a fraction of a car length.