A wind tunnel is an enclosed structure that lets researchers simulate the same conditions a real aircraft would encounter as it flies through the atmosphere. In a wind tunnel a highly-instrumented aircraft model or an aircraft part is held steady while air moves past it to simulate flight conditions. Wind tunnels let researchers safely take measurements often impossible to make while an aircraft is flying.
Computers collect the instrument readings for later analysis by researchers.
Wind tunnels test new flight concepts before any flights are made. Researchers measure the speed of sound using Mach numbers, a measurement named after the early 20th Century scientist Ernst Mach. Mach one is the speed of sound, Mach two is twice the speed of sound, and so forth. The 8x6 SWT can test aircraft from 250 miles per hour to Mach two, nearly 1500 miles per hour. Testing in the 8x6 SWT began in 1948.