Abstract
This paper reports the aerodynamic development of the ultra low economy vehicle, motor show car FS3. Using the wind tunnel testing and CFD (computational fluid dynamics), the Cd 0.23 of ES3 that is the lowest drag coefficient among the compact cars is obtained. The outstanding aerodynamic characteristic is achieved by the great reduction of the wake region behind the vehicle. It is obtained by optimizing the rear body shape, improving the flow of body side with the reduction of blowing out from the wheelhouse, and increasing the amount of flow and the speed under the floor that is obtained by rising the underfloor height and smoothing the underfloor surface.