l8 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 93 



slats, and the nozzle made possible speeds of up to 35 meters per 

 second/^ 



GUSTAVE EIFFEL 



Gustave Eiffel built his first wind tunnel on the Champ de Mars in 

 1909. It was the open-jet nonreturn tunnel with an airtight testing 

 chamber, known as the Eiffel type. The air current was cylindrical, 

 1.5 meters in diameter, later enlarged to 2 meters."" 



In 191 1 Eiffel moved to Auteuil and built a new and larger labora- 

 tory, which he later turned over to the French Government. 



NATIONAL PHYSICAL LABORATORY 



The N. P. L. built its first large wind tunnel in London in 1910. It 

 was 4 by 4 feet in cross-section and was supported inside another tun- 

 nel 8 by 8 feet. The space between the walls of the two tunnels was a 

 return passage for the air, which was drawn through the 4-foot tunnel 

 by a Sirocco fan, driven by a 15 hp. engine." 



This tunnel was not very satisfactory and was replaced in 1912 with 

 a closed- jet nonreturn flow tunnel. 



The tunnels of Prandtl, Eiffel, and the N. P. L. have been very 

 briefly described, as their main features are generally known, and full 

 descriptions are readily available.''" They end the pioneer period and 

 begin a new era in wind-tunnel history. Before these three laboratories 

 were established, powered flight had become a proved fact, and air- 

 ships had met with considerable success. The necessity for reliable 

 laboratory research soon became universally recognized and wind- 

 tunnel laboratories were built and maintained by governments and 

 institutions, as well as by private agencies. 



I 



■■Aerophile, vol. 27, pp. 266-268, illus., June 15, 1909. 

 Soc. ingenieurs civils France, Mem. et C. R. Traveaux, vol. 65, pp. 61-78, 

 illus., July 1912. 



" Eiffel, Gustave, Installation d'un laboratoire d'aerodynamique. Paris, 1910. 

 La resistance de I'air et I'aviation, experiences effectuees au Laboratoire du 

 Champ de Mars. Paris, 1910. The resistance of the air and aviation, experi- 

 ments conducted at the Champ de Mars Laboratory. Translated by Jerome C. 

 Hunsaker. London and Boston, 1913. 



^^ Great Britain Advisory Committee for Aeronautics, Rep. 1909-10, pp. 14-15, 

 2 folded plates. 



Flight, vol. 2, pp. 226-227, March 26, 1910. 



^' Zahm, A. F., Report on European aeronautical laboratories, Smithsonian 

 Misc. Coll., vol. 62, no. 3, 23 pp., 11 pis., 5 figs., 1914. 



