The story recounted here was, in sum, about the success and the failure of Leonard Bairstow. The whole story turned on the scientific and technological significance of the key instrument for aeronautical research: the wind tunnel. Bairstow made full use of it, defended the validity of the data from it, and argued for the continuation of model research in it. He further promoted the attempt to standardize the performance of wind tunnels all over the world and to accord the NPL a central role. For all these efforts to connect the inside and the outside of the laboratory, I compared him to a laboratory director in Latour’s Science in Action and Pasteur in Pasteurization of France.
At first, Bairstow was exceptionally successful. His prewar stability research was applauded at home and abroad. Despite an American request, the British regarded it too important to disclose. Through such accomplishment, Bairstow attained fellowship in the Royal Society, served on the Air Board, and became Professor of Aeronautics at Imperial College. He became an extremely powerful figure in the British aeronautical community.
Bairstow’s position would have been further enhanced had the NPL model of wind tunnel research been standardized around the world. That was one object of the decade-long International Trials project. During this project, however, it turned out that Bairstow’s previous argument for ignoring the scale effect was called into question. Prandtl’s new aerodynamic theory challenged Bairstow’s position. French use of the Prandtl correction sparked a scientific debate on the validity of Prandtl’s aerodynamic theory. Acceptance of the Prandtl correction implied criticism of Bairstow, who had insisted on the negligibility of the scale effect.
While Bairstow served as an excellent middleman between theoretical scientists and practical engineers in conducting model research on stability, he failed to be such a middleman between Teddington and Famborough. He might have been more sensitive and generous to the full-scale experimenters at Famborough, initiating a theoretical and experimental research program on scale effect. Instead, he defended his model research like a lawyer at court by pointing out possible weaknesses in full-scale testing. Perhaps the wartime emergency and the position of the Air Board prevented him from taking a more discreet stance on this matter. In any event, he left himself open to later criticisms and repudiation. In the end, the renamed Scale Effect subcommittee approved the desirability of constructing a new variable-density wind tunnel developed by American engineers. This was a clear judgment that Bairstow had been wrong.
If we take Latour’s argument seriously, we could pose a question. Why did Prandtl’s theory prevail in the postwar world? From 1904, when he arrived at Gottingen, to 1918, the year of armistice, Prandtl succeeded, like Bairstow, in conducting aerodynamic research and expanding his research facilities. But after the war, he was placed in severely limited conditions on poor financial and material bases and with almost no communication with foreign investigators. Yet his aerodynamic theory soon won over aeronautical engineers all over the world. It was mainly not through Prandtl’s own effort but through the efforts of foreign engineers, and his disciple in the case of the United States, that his theory was accepted worldwide. In this connection, we could turn our attention to the RAE engineers who championed the introduction of Prandtl’s theory in Britain. In arguing for the validity of the German theory and specifically promoting the application of Prandtl correction, they succeeded in restoring the position held by their colleagues at Famborough in the wartime scale-effect controversy.64