WIND TUNNELS OF NASA

 

Chapter 2 - A Heritage Lost and Regained

An Earthbound American Aeronautical Pioneer

 

[10] The first post-Wright wind tunnel laboratory dedicated to aeronautical research was built in America, despite what was just said about the lack of aeronautical interest in this country. Almost coincident with the Wrights' small developmental wind tunnel, Albert Zahm, a professor at Catholic University in Washington, D.C., began operating a wind tunnel with the unheard of test section dimensions of 6 x 6 feet. Who sponsored this tunnel ? Not the U. S. government and not Catholic University, but a wealthy industrialist, Hugo Mattullath, who saw a commercial future in aviation far beyond the frail, almost ridiculous craft then straining to stay aloft for a few moments.

The Zahm facility was remarkable, not only because of its size but also by virtue of its unique methods of instrumentation, calibration, and application to aeronautical research. A test section 40 feet long and 6 feet square employed flow straighteners of honeycomb and cheesecloth to assure homogeneous flow. Zahm's ingenious pressure gages had sensitivities of a millionth of an atmosphere; that is, the pressure exerted by only 1/3 inch of air. With this impressive research facility, Zahm did pioneering work on the drag of dirigible hulls. Most important, he was the first to look closely at the drag losses due to the friction of air flowing over aircraft surfaces. Contrary to the belief of Langley and most of his predecessors, Zahm demonstrated that skin friction was indeed a major element of drag at subsonic speeds.

The momentum of the Wrights, followed so closely by Zahm's important contributions (now almost forgotten), should have maintained U. S. leadership in aerodynamics despite official indifference. Unhappily, Mattullath died before he saw anything approaching practical commercial results. Without financial support, work ground to a halt at Zahm's tunnel. In 1908 it was closed down completely.


Albert Zahm's air tunnel

 Albert Zahm's "air tunnel" built at Catholic University, Washington, DC, in 1901 with funds from an industrial sponsor. (Courtesy University of Notre Dame Archives)

 


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