Wednesday, June 21, 2006

Wind Tunnel

What is a wind tunnel? Simply put, a wind tunnel is a tube or tunnel through which air is blown. What are they used for? A wind tunnel is used to simulate flight conditions or to study how air moves around an aircraft or part of an aircraft. This is immensely safer than testing a new design in flight.

The site, Parts of a Wind Tunnel, shows the five major parts of a wind tunnel - the settling chamber, contraction cone, test section, diffuser and drive section. The settling chamber evens out the airflow. The contraction cone reduces the volume of the airflow and increases its speed. The object being tested, whether is be a whole airplane or just a part, is placed in the test section. The diffuser then slows the air down. The drive section, which may simply be a large fan, is the power that drives that air through the tunnel. If the reader would like to make their own wind tunnel, there are many web sites with instructions. Make a simple wind tunnel gives directions for making one from a furnace pipe and egg cartons. Another site for making a wind tunnel is Wind Tunnel , a NASA sites.

The first wind tunnel dates back to the mid-1700. Initially, an apparatus called a "whirling arm" was used. Objects were attached to the end of the arm and then the arm was spun. It wasn't until approximately 1871 that Frank H. Wenham constructed the first wind tunnel. To see how the whirling arm and the wind tunnel figure into the chronicles of flight, take a look at a timeline of the history of flight. Interestingly, the Wright Brothers used a wind tunnel. Their wind tunnel looks quite primitive by today's standards. This can be seen by comparing the Wright Brothers' wind tunnel with the wind tunnels used by NASA. But they were able to use it to obtain the correct aerodynamic data, which enabled them to fly. If one would like to get an idea of what it was like to use the Wright Brothers' tunnel, the site Interactive Wright 1901 Wind Tunnel is an Java applet that simulates its operation. The site Java Virtual Wind Tunnel simulates a modern day wind tunnel.

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