The body shape of minimum drag

After a short review of the work done in the past to reduce the aerodynamic drag of a body moving in the vicinity of the ground, a new theoretical method is developed in order to determine the shape of the body when a certain lift distribution is imposed. Considerations on the induced drag suggest that the total lift is zero and the pitching moment are zero. These conditions together with that of gradual variation of the area and shape of the cross sections of the body lead to the determination of the basic shape of the body. A model was realized and tested on the Pininfarina wind tunnel. The results show a good substantiation of the theory and a very low drag coefficient. The dimensions of the model were such as to achieve the actual Reynolds numbers of motor cars. Energy implications of a reduction on the aerodynamic drag are also indicated.