ENGINEERING EXPERIMENT AND ENGINEERING THEORY: THE AERODYNAMICS OF WINGS AT SUPERSONIC SPEEDS, 1946-1948

By 1946, though the possibility of supersonic flight had yet to be proven by the Bell XS-1, research engineers had begun to explore the anticipated aerodynamic problems. This paper offers an inside look at a contribution to those early days of supersonic aerodynamics.

Artifacts, by their nature, must work in the real, physical world. Engineers strive, insofar as they can, to bring that world into the design office through general understanding, ways of thinking, theoretical design methods, and design data. Research engineers (and sometimes design engineers themselves) work to develop these means by synergistic recourse to theory, experiment, and use. Edward Constant speaks of these – in reverse order and aeronautical context – as “technological empiricism (building it), careful but empirical testing (trying design families in wind tunnels), and theoretical investigation (development of formal aerodynamic theory).” These “are equal in the sense that they ultimately discover the same world,”1 that is, they are mutually validating and authenticating. The present case study recounts the earliest systematic investigation, by joint theory and experiment in the years 1946-48, to assess the potential of the then newly developing theory as a design tool for airplane wings at supersonic speeds. The story thus shows the typically synergistic use in aerodynamic research of theory and experiment in the pursuit of knowledge, plus the role therein of theory as a kind of “artifact” or “tool” analogous to the wind tunnel. It also illustrates what I intend above by “general understanding” and “ways of thinking” and to exemplify other concerns of interest for historical analysis.

As in a companion article,2 the story is based – in this case mainly – on my own experiences in the 1940s as a research engineer at the Ames Aeronautical Laboratory of the National Advisory Committee for Aeronautics (NACA) near San Francisco. Though I shall place the work in historical context, activities in which I participated will predominate, and the situation will be described as it appeared to our group at Ames. As in the other article, I shall write as objectively as I can, using my recollection as critically as I would any other historical source. At the same time, I shall try to convey something of the spirit and feel of the activity. To make clear the complexities of the experimental-theoretical interaction, considerable detail will be needed.

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P Galison and A. Roland (eds.), Atmospheric Flight in the Twentieth Century, 157-180 © 2000 Kluwer Academic Publishers.