Jun 12, · For a while, I've known that planes, rockets, and even cars are designed by subjecting small scale models of them through an instrument known as a wind tunnel. However, the wind tunnels I know of are either very big, expensive and hard to access unless you have connections or small pitiful demonstrations the science museums use . Although the form of a wind tunnel can vary, all wind tunnels have a drive system, a test section, use a model that is supported in an airstream and whose characteristics are measured by test instrumentation. May 07, · This DIY wind tunnel works the same way as most open-circuit wind tunnels do. Air enters the Contraction Cone, where the inlet is larger than the outlet. This reduction in chamber size speeds up the air as it enters the tunnel.