Investigations of low drag shapes for passenger vehicles were conducted in the 1930s but production cars of today have yet to approach the potential drag coefficients shown by that early research. Furthermore, the adoption of low drag styles has been resisted because of a perception of compromise to the exterior style and so recent aerodynamic developments have concentrated on changes to non-styled surfaces. However, environmental and ecological pressures are placing increasing demands on manufacturers to produce energy efficient vehicles and the contribution of aerodynamics in that equation is increasing, particularly with the adoption of technologies such as regenerative braking and measurements being made using more real-world use driving cycles. Relying on non-styled surfaces alone for drag reduction is unlikely to be sufficient to deliver the improvements required. In addition, and there is even some suggestion that passenger cars which are visibly streamlined have more appeal because owners can show their ecological credentials.
In this paper the authors discuss streamlined styles of the past and demonstrate that it is possible to re-evaluate these shapes using computer-based styling and CFD. Whilst recognising the importance of styling in sales, it is suggested that the integration of aerodynamics and styling will become essential for significantly lower drag forms to be presented in an aesthetically pleasing exterior design which also takes advantage of the potential changes in architecture offered by new propulsion technologies, materials, electronics and manufacturing technologies.