Model behaviour

Understanding the benefits and limitations of scale model wind tunnel programmes

- JAHEE CAMPBELL-BRENNAN

Wind tunnel testing has a fascinating history, beginning in the aerospace industry. As testing methods became more sophisticated and laboratory testing evolved, a need was identified to provide a method of validating design concepts. The Wright brothers were the first to achieve controlled flight as they built a tunnel to calibrate the characteristics of wing profiles and showed that the accepted characteristics were wrong.

However, few tunnels existed that would be capable of managing a 1:1 scale prototype. Aerospace engineers quickly figured out there were many advantages to preparing scale models. Namely, it enabled testing to take place at all, but furthermore cost, materials use and build times were slashed when compared to full-size prototypes.

Cars by their very nature operate close to, and in contact with, the ground, so automotive wind tunnels differ substantially in design to aerospace ones. A moving ground plane and effective boundary layer control are critical features but, in the early days of automotive wind tunnel testing, these weren’t available to full-size models. The concept of scale models within automotive and motorsport testing was therefore born out of similar necessity to aerospace.