NO. 4 PIONEER WIND TUNNELS R ANDERS-PEHRSON I 3 



About 200 wing models made of sheet metal were tested in the 

 wind tunnel. Each model was tested at 14 different angles of inci- 

 dence, varying from 0° to 45°. Tests were also made to ascertain 

 the effect of varying the aspect ratio, of superposing surfaces, etc. 

 Great care was taken in making the tests ; no one but the observer was 

 allowed near the tunnel while it was in operation, and he kept the same 

 position during the extent of the test, in order not to disturb the air 

 current. The results were meticulously noted, and when completed 

 they formed a valuable collection of aerodynamic tables which were 

 later used by the Wrights as the basis for their design. Around 

 Christmas 1902 these experiments came to an end, and the apparatus 

 was taken down." 



This construction and the Wright Brothers' investigations there- 

 with formed one of the chief factors leading to their success at Kitty 

 Hawk on December 17, 1903. 



T. E. STANTON 



The first wind tunnel at the National Physical Laboratory in Lon- 

 don was set up several years before aeronautics became a subject of 

 research at that institution. This predecessor of the great modern 

 N. P. L. tunnels was built in 1903 by Dr. Thomas E. Stanton, for 

 investigation of wind pressure on surfaces and structures. 



Stanton's tunnel was vertical, the upper part a cylinder 2 feet in 

 diameter and 4^ feet long, terminating in a square box 4 by 4 feet, 

 and I foot 3 inches deep where the balance was inserted. Underneath 

 this, connected by a shorter length of pipe of the same diameter as 

 the upper part of the tunnel, was the fan chamber. The fan, which 

 produced the wind in the tunnel by suction, was driven by an electric 

 motor and could be regulated to give air speeds from 5 to 30 feet per 

 second. 



The balance comprising a horizontal lever carried on knife edges, 

 had a sliding scale, and a scalepan with a dashpot for damping the 

 vibrations. It was inserted in the center part of the tunnel, so that 

 the model projected into the cylindrical section. The long arm of the 

 lever was hollow and could be connected with a sensitive manometer 



" Aeronautical Journ., vol. 20, pp. 73-74, July-Sept. igi6. 

 Unpublished letters of Wilbur Wright to Octave Chanute, now in the 

 Library of Congress. 



