Of the CW value is the coefficient of drag of a vehicle. The smaller the measured value in a wind tunnel, the better the flow properties of the cars. Accordingly, a low drag coefficient can contribute to the reduction of consumption.
Of the CW value is influenced by various factors. So have prototypes that have a low air resistance, ideally a drop-shaped body with a long, narrow tail. In addition, an underbody covering, small gap and joint dimensions and clad wheel arches and smooth rims have a positive effect on a low drag coefficient.
Cars with a low drag coefficient, for example, the Mercedes Benz E-class coupe (C 207, Cw value: 0.24), as well as the prototype of the 1-liter cars of VW (XL1, Cw-value: 0.159)
As important as the drag coefficient for the aerodynamics is the actual air resistance of a vehicle is also dependent on its end face. This is measured in square meters and are combined with the CW value Information about the actual drag.