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Wind Tunnel History

Drawing of exterior of Altitude Wind Tunnel

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Wind Tunnels: Almost as long as humans have contemplated air travel, they have sought to create flight conditions in a controlled environment to assist the design process. Today, computer-aided design and flight simulators can replicate flight conditions, but traditionally there were two basic methods for simulating flight with model aircraft on the ground—propelling an aircraft through the air or subjecting a stationary aircraft to an airflow. The earliest simulation tools in the mid-18th century used this first method. These "whirling arms" consisted of a pole with a model aircraft held on an extended arm. The arm was then rotated rapidly in circles to simulate actual flight.

How Tunnel Works

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The second, and most successful, form of testing was the placement of a stationary model inside a tunnel. Flight was simulated when air was pulled through the tunnel and past the model aircraft. The tunnel method proved to be more practical and efficient than the whirling arms. The tunnel operator can control wind speed and other atmospheric conditions, as well as the aircraft’s angle of attack and attitude. Although there are full-scale wind tunnels in existence, most are not large enough to accommodate an actual aircraft. Instead, scaled-down models, which are comparatively inexpensive and easy to modify, are used.

Vacuum Chamber History

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Vacuum Chambers: The use of vacuum chambers to simulate high altitudes began during World War I. The air pressure decreases as altitude increases. By reducing the quantity of air in a chamber or tank, one can simulate the air pressures of high altitude. This was done for a variety of aeronautics uses, including studying engine behavior and the effect of altitude on pilots.

How SPC Works

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Initial space flights during the late 1950s and early 1960s showed the behavior of engines, flight systems, and hardware was affected by the vacuum and cold temperatures found in space. There was a need to test full-size versions of these items in a vacuum chamber before the mission. In the early 1960s there was a wave of large vacuum chambers built for this purpose.

Additional Research Material

Additional documents describing the operation of the Altitude Wind Tunnel and Space Power Chamber No. 1 can be found in the Facility and Research sections of this Web site.