By Ian Graham
Defense Media Activity

Wind tunnels, the tools used to simulate airspeed environments to test flight capabilities, have come a long way since the Wright brothers built a box with fans to test a kite model.

At the Air Force’s Arnold Engineering Development Center White Oak site here, the breadth of that change is apparent. The original supersonic tunnel, created by Werner von Braun and other German scientists to test weapon aerodynamics in World War II, sits in a lobby a few yards away from its most-recent descendent, Hypervelocity Wind Tunnel 9, which can produce wind conditions simulating hypersonic speeds, up to Mach 14.

Site director Dan Marren said Tunnel 9 is unique in the truest sense of the word: there are no wind tunnels like it anywhere else. The tunnel uses a 200,000-cubic-foot, seven-story sphere as a vacuum on one end, and nitrogen compressed to 30,000 pounds per square inch and heated to 3,000 degrees Fahrenheit to create a pressure ratio of about 1 million, which is needed to create hypersonic wind conditions.

“Anything that goes fast will probably come to us [for testing],” he said.

The tunnel is revolutionary because of the amount of high quality data it produces, Marren said. It can run two tests daily, and record large amounts of data while moving the model dynamically. Prior to its creation, he noted, it might take two months to gather the data from a day’s work with Tunnel Nine. It’s especially important, he added, because neither the research nor the scientists involved can be replicated.

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