REVIEWS
“A masterpiece of writing and research. David Bloor brings his varied background to the table, writing the only book that describes a wonderful mixture of the scientific, historical, philosophical, and sociological forces that help to explain the ‘enigma’ of the aerofoil.”
— John D. Anderson Jr., National Air and Space Museum, Smithsonian Institution
“David Bloor’s The Enigma of the Aerofoil sets out to explain the development of aerodynamics in Britain and Germany early in the twentieth century. Why, he asks, was it in Germany, and not in Britain, that practitioners produced a fusion of theory with aerofoil design when the basic concept upon which the Germans relied, that of circulation about an aerofoil with the flow treated otherwise as an ideal fluid, had long before been used by Rayleigh in Britain for the flight of a tennis ball? Bloor probes this ‘enigma,’ combining deft analysis of the technical arguments involved with a sure examination of the social frameworks within which his several protagonists worked. Along the way, he grapples with the character of reasoning and practice when scientific theory confronts engineering reality. Written by a founder of the strong program in the sociology of science, Bloor’s Enigma is among the very finest histories that raise these difficult and important questions—one that succeeds by refusing to break the intellectual from the social, and both from the exigencies of engineering practice.”
— Jed Z. Buchwald, California Institute of Technology
“In The Enigma of the Aerofoil, David Bloor paints a seamless picture of how and why British and German theorists struggled, typically in different ways, to make an aerodynamic theory that corresponded even approximately with aeronautical practice. In doing so, Bloor gives us a stark reminder of the extraordinary power—and the limits—of mathematics and mathematicians in their many guises. As a result this book will help redefine what we take the central sciences and technologies of the twentieth century to be, and how we study them.”
— David Edgerton, Imperial College London
“Valuable for everyone interested in the history of aeronautics, fluid dynamics, early aircraft, applied mathematics, and the sociology of science and engineering. Highly recommended.”
— A. M. Strauss, Vanderbilt University, Choice
“A detailed technical history of the development of airfoil theory, a central achievement of modern aerodynamics . . . [as well as] a careful comparative analysis of the two main schools of aerodynamic theory in the early twentieth century, one British and the other German . . . . [Bloor] provides penetrating insights into different modes of reasoning involved in the application of mathematical theory to technological practice.”
— Eric Schatzberg, Metascience
“The reader is expertly led on a narrative journey that is filled with technical detail on the accomplishments of a bygone era.”
— Thomas J. Pence, Michigan State University, Meccanica
“Historians and philosophers rethinking the underpinnings of myriad scientific projects through the lens of technoscience would do well to grapple with Bloor’s magnum opus. It rewards the patient reader with a partial and situated toolkit to face the evolvingdesigns of a nature we help make.”
— Matthew Wisnioski, Virginia Tech, Studies in History and Philosophy of Science
"Superb. . . . Joins excellent recent work on the intriguing but technically demanding subject of the history of fluid dynamics by Olivier Darrigol and Michael Eckert, and opens the field to historical-sociological analysis. Bloor’s extensive case study compares the development of aerodynamical theories of lift in Britain and Germany from 1909 to 1930. . . . One of the most convincing cases since Leviathan and the Air Pump for the simultaneously cognitive and social character of knowledge production."
— Daniela Helbig, University of Sydney, Australia, Endeavour
TABLE OF CONTENTS
List of Illustrations
Acknowledgments
Introduction - David Bloor
DOI: 10.7208/chicago/9780226060934.003.0001
[airplanes, lift, lifting force, wing, aerodynamics]
This book discusses the question of why airplanes fly, but the problem is approached in a slightly unusual way. The author describes the history behind the technical answer to the question about the cause of “lift,” that is, the lifting force on the wing. The path by which the experts, after much disagreement, arrived at the account they would now give is analyzed here. This chapter, therefore, does not simply assert that airplanes fly for this or that reason; it asserts that they were understood to fly for this or that reason. The main interest here is in the fact that different and rival understandings were developed by different persons and in different places. The author cannot speak as a professional in the field of aerodynamics; nor is his position exactly that of a layperson. Instead, he speaks as a historian and sociologist of science who is poised between these categories. (pages 1 - 8)
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Mathematicians versus Practical Men - David Bloor
DOI: 10.7208/chicago/9780226060934.003.0002
[Advisory Committee for Aeronautics, aeronautics, aviation, British aeronautics, aeronautical science, scientists, engineers]
This chapter focuses on the Advisory Committee for Aeronautics (ACA) and the arguments regarding whether it provided the best or the worst in the field of aeronautics. Since it was founded in 1909, the ACA was, and was intended to be, the brains in the body of British aeronautics. It offered to the emerging field of aviation the expertise of some of the country's leading scientists and engineers. In its early years, however, some people in Britain argued that the ACA failed to live up to its reputation. For these critics, the ACA held back the field of British aeronautics and encouraged the wrong tendencies. The reason for these strongly divergent opinions was that aviation in general, and aeronautical science in particular, fell across some of the many cultural fault lines running through British society, and these fault lines were capable of unleashing powerful and destructive forces. (pages 9 - 39)
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The Air as an Ideal Fluid - David Bloor
DOI: 10.7208/chicago/9780226060934.003.0003
[fluid dynamics, British, German, lift, drag, hydrodynamics, aerodynamics]
This chapter discusses fluid dynamics and how it provided the intellectual resources that were common to both the British and German work on lift and drag, although the stance toward that common heritage was often very different in the two cases. This chapter is meant to be a description of this common heritage and these shared resources, providing the required background and orientation. Here, the author does his best to explain the basic concepts in simple terms, even though this hardly does justice to the ideas and techniques that are mentioned. A sketch of some of the initial, mathematical steps that went into their construction is provided in order to convey something of the style and feel of the work. At the end of the chapter, the main points are then summarized in nonmathematical terms. (pages 40 - 78)
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Early British Work on Lift and Drag - David Bloor
DOI: 10.7208/chicago/9780226060934.003.0004
[discontinuity, ACA, lift, mathematical analysis, aircraft wing, fluid, Rayleigh, discontinuous flow, practical men]
This chapter discusses discontinuity and how it became the main focus of the ACA in its theoretical and experimental research efforts concerning lift. The immediate research aim of the ACA was to provide a mathematical analysis that would predict the forces exerted on a flat or curved plate immersed at an angle to a flowing fluid. The plate was to function as a simple model of an aircraft wing, and the mathematically idealized fluid, necessary to perform the calculations, was to act as a model of the air. To calculate the forces, researchers needed a precise and quantitative picture of the flow around the wing. For the British, the best available guess was provided by Rayleigh's important work on discontinuous flow, which appeared to the ACA as the rational place to start. This chapter describes this work and, in later sections, contrasts it with the ideas about lift put forward by the leading representative of the “practical men.” . (pages 79 - 110)
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Lanchester’s Cyclic Theory of Lift and Its Early Reception - David Bloor
DOI: 10.7208/chicago/9780226060934.003.0005
[circulation theory, lift, Great War, aerodynamics, discontinuity theory, vortex theory, Frederick Lanchester, ACA]
This chapter lays the foundations for an explanation of the negative response to circulation theory. Given that the circulation theory later came to be accepted as the correct account of lift, this insistent rejection has long been seen as a puzzle. By the beginning of the Great War the British experts on the ACA who were responsible for research in aerodynamics had effectively abandoned the discontinuity theory of lift. There was, however, a known alternative: the circulatory or vortex theory that had been developed by Frederick Lanchester. It would be reasonable to expect that this theory would now become an object of some interest even if it had been ignored at the outset of the ACA's work when they had concentrated on Rayleigh's achievements, but, rather than turning to the circulation theory, the ACA again treated it as if it were of no merit. (pages 111 - 159)
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Two Traditions: Mathematical Physics and Technical Mechanics - David Bloor
DOI: 10.7208/chicago/9780226060934.003.0006
[circulation theory, mathematical physics, disciplinary standpoint, Lanchester, mathematical physics, technical mechanics, Cambridge]
This chapter presents the reasons advanced against the circulation theory of lift proposed by non-engineers who worked in the British, and particularly the Cambridge, tradition of mathematical physics. If the objections were the expressions of a disciplinary standpoint, located at a specific time and place, then perhaps the resistance to the circulatory theory would be explicable as a clash of cultures, institutions, and practices. Such an explanation would not imply any devaluation of the reasons that were advanced against the circulatory theory. It would not be premised on the assumption that these reasons were not the real reasons for the resistance. On the contrary, the intention would be to take the objections against the theory in full seriousness and to probe further into them. The aim of this chapter is to outline a theory that could explain the negative character of the British response to Lanchester's theory. (pages 160 - 199)
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Technische Mechanik in Action: Kutta’s Arc and the Joukowsky Wing - David Bloor
DOI: 10.7208/chicago/9780226060934.003.0007
[infinite wing paradigm, Wilhelm Kutta, two-dimensional flow, circular arc, Rayleigh, inviscid fluid, irrotational flow, Joukowsky, Gottingen, Berlin]
This chapter addresses the “infinite wing” paradigm with an analysis deliberately confined to a two-dimensional cross section of the flow in which the wingtips are ignored. It was Wilhelm Kutta in Munich who triggered the striking progress in the field of two-dimensional flow that was made in Germany before and during the Great War. His work is the starting point of this chapter. Where Rayleigh used a simple, flat plane as a model of a wing, Kutta used a shallow, circular arc. Both men treated the air as an inviscid fluid, but where Rayleigh postulated a flow with surfaces of discontinuity, Kutta postulated an irrotational flow with circulation. Joukowsky, a Russian who published in German, then showed how to simplify and generalize Kutta's reasoning. A variety of other workers in Gottingen, Aachen, and Berlin, starting from Kutta's and Joukowsky's publications, carried the experimental and theoretical analysis yet further. (pages 200 - 246)
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The Finite Wing: - David Bloor
DOI: 10.7208/chicago/9780226060934.003.0008
[theory of lift, wing profile, Kutta, Joukowsky, planform, wingtips, high aspect ratio, low aspect ratio, finite length, wing]
This chapter divides the theory of lift into two parts: the theory of the wing profile, that is, the wing sections of the kind studied by Kutta and Joukowsky, and the theory of the planform of the wing, the shape of the wing when seen from above. The designer may choose a simple, rectangular shape or give the wing a more aesthetically pleasing curved leading or trailing edge. The wingtips may be rounded or square, and, most important of all, the wing may be made long and narrow, referred to as high aspect ratio, or short and stubby, referred to as low aspect ratio. The discussion here concerns the distribution of the lift along the span of the wing and the properties that a wing possesses in virtue of its finite length and the flow around the wingtips. (pages 247 - 303)
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“We Have Nothing to Learn from the Hun”: - David Bloor
DOI: 10.7208/chicago/9780226060934.003.0009
[circulatory theory, lift, Great War, flow of information, good faith, German, true theory, British, theory acceptance]
This chapter aims to describe some of the contingencies that bore upon the fortunes of the circulatory theory of lift in Britain after the Great War. It begins with some observations about the flow of information between German and British experts before, during, and after the Great War. Given good faith and genuine curiosity, a true theory will eventually prevail over false ones. These sentiments make for good aphorisms, but the epistemology remains questionable. Even if a theory were right, there would still be the need to understand the contingencies and complications of the historical path leading to its acceptance. (pages 304 - 339)
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The Laws of Prandtl and the Laws of Nature - David Bloor
DOI: 10.7208/chicago/9780226060934.003.0010
[circulation theory, perfect fluid, irrotational motion, Lanchester, Taylor, Lanchester, Prandtl, Glauert, aerofoil theory]
This chapter puts into question Taylor's rejection of Lanchester's idea that the flow of air over a wing was describable in terms of a perfect fluid in irrotational motion with circulation. It is argued here that if Prandtl was right, then Taylor had been wrong. With Glauert at the helm, the postwar argument in the ACA seemed to be going in Prandtl's direction, and the circulation theory was gaining ground. In 1923, Glauert wrote to Prandtl to tell him that “aerofoil theory has certainly aroused much interest here and it would not be an exaggeration to say that it has revolutionized many of our ideas.” Taylor, however, was not to be easily convinced that his earlier reservations had been misplaced. In the postwar discussions, he made it his job to scrutinize Glauert's reasoning and to oppose it whenever he detected a logical gap or a questionable premise. (pages 340 - 398)
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Pessimism, Positivism, and Relativism: Aerodynamic Knowledge in Context - David Bloor
DOI: 10.7208/chicago/9780226060934.003.0011
[sociology of knowledge, Strong Program, circulatory theory, technological innovation, relativism, aviation, aerodynamic knowledge]
This chapter begins with a brief account and defense of the main features of the Strong Program in the sociology of knowledge and the perspective it is designed to encourage. It is a perspective very different from the naive, philosophical narratives identified at the end of the last chapter and mentioned in the introduction. The chapter then addresses two broader questions. First, was the resistance to the circulatory theory of lift an all-too-typical example of British failings in the field of technological innovation? The author argues against this pessimistic reading here. Second, what about the controversial topic of “relativism”? Aviation, as a successful and impressive technology, is often cited as a quick and decisive refutation of relativism. This line of antirelativist argument is groundless and obscures the most striking characteristics of aerodynamic knowledge. (pages 399 - 446)
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Notes
Bibliography
Index
