Chapter 2 Building a Research Establishment The American Way The only people so far who have been able to get at something like accurate results from wind-tunnel experiments are the workers at the Experimental Station at Langley Field, which is run by the National Advisory Committee for Aeronautics of the United States of America. Thanks to the wealth of the United States and the high intelligence of those who are charged with the task of aeronautical experiments, workers in the American research establishments have acquired knowledge that is in many ways far ahead of anything we have in this country. And they have it very largely by what is called “ad hoc research,”—that is to say, going and looking for the solution of one particular problem, instead of experi- menting around blindly in the hope that something may turn up, after the fashion which is known as “basic research.” The above editorial comment by C. G. Grey, a prominent British aeronautical engineer and editor of the aviation journal The Aeroplane, appeared in the 6 February 1929 issue of that journal. From the Wright Bicycle Shop to the Langley Full-Scale Tunnel For those who followed the ingenious Wright brothers into the air after 1903, the maturation of the airplane depended on a growing and increasingly sophisticated understanding of aerodynamics, for there was still much about flight that was unknown. The route to greater aeronautical knowledge in the post-Wright era was not a straight highway. To the extent a map even existed, it offered a maze of twisting roads involving trial-and-error design of new flying machines; dogged pragmatic testing; deeper scientific inquiry; and, perhaps most importantly, a shrewd combination of the best that both theory and experiment had to offer. Yet for the aeronautical scientists and engineers in pursuit of aviation progress in the early twentieth century, there was perhaps no surer course to progress than the one laid out by the Wright brothers themselves. Unfortunately, not everyone in the brave new world of aeronautics understood the Wrights’ path to success. Many wrongly interpreted their invention of the airplane either as the heroic act of ingenious mechanical tinkerers or as a basic scientific discovery, rather than as a solid technological program of engineering research and development. 237 238 Chapter 2: Building a Research Establishment In fact, the Wrights’ first successful flying machines, starting with their 1902 glider and the 1903 airplane that followed, not only represented key breakthroughs in their efforts to master heavier-than-air flight, but also bore testimony to the irreplaceable value of combining careful laboratory experiments with actual flight testing. In 1915, twelve long years after the epochal Wright flight, the U.S. Congress established the National Advisory Committee for Aeronautics, the predecessor of present-day NASA, with the mission “to supervise and direct the scientific study of the problems of flight with a view to their practical solution.” Eventually this agency recreated the Wrights’ formula for success in a series of federal research laboratories.1 The NACA accomplished this, originally, by building an extraordi- nary community of aeronautical engineers, scientists, technicians, and test pilots at the Langley Memorial Aeronautical Laboratory (LMAL) in Tidewater, Virginia— the NACA’s first and, until 1941, only research facility.2 At NACA Langley, the lab- oratory staff faced, and eventually resolved, many fundamental questions about how to plan and conduct institutional aerodynamic research. These questions dealt with issues of how research should be focused, what sort of facilities should be built, what type of experimental investigations should be carried out, and how experimentalists and theoreticians could work together fruitfully. The early NACA community also dealt with the issue of whether science or engineering should be in control of the research program, and especially whether the German academic laboratory model could be transferred successfully to America—or whether an American lab would have to find its own way. Through the resolution of these issues, in conjunction with a growing list of important achievements in aeronautics, a sustainable organizational identity for Langley and for the subse- quent NACA laboratories began to evolve. The result was a dynamic and highly creative organization that, although its original facility was named after scientist Samuel P. Langley, actually reflected more the systematic engineering approach of Wilbur and Orville Wright, with an emphasis on a search for practical solutions. Throughout this sometimes torturous process, the NACA helped a fledgling American aircraft industry advance the airplane in a few short decades to an astoundingly high level of technological performance and corresponding impor- tance in modern society. 1 On the history of the National Advisory Committee for Aeronautics, the place to start is Alex Roland’s Model Research: The National Advisory Committee for Aeronautics (Washington, DC: NASA SP-4103, 1985), two volumes. 2 NACA Langley’s history is told in James R. Hansen’s Engineer in Charge: A History of the Langley Aeronautical Laboratory (Washington, DC: NASA SP-4305, 1987). From the Wright Bicycle Shop to the Langley Full-Scale Tunnel 239 In building a test device like the wind tunnel and then using it systematically to generate reliable data, the Wright brothers forged a solid link between aeronautical research and the design of successful aircraft. SI Negative No. A-2708-G Center stage in NACA research, from the beginning, was a unique device designed for basic aerodynamic investigation: the “wind tunnel.” Following the initial achievement of flight, wind tunnels quickly became the central research facilities at aeronautical laboratories all over the world. This, too, was a legacy of the Wright brothers’ approach, for the aerodynamic shape of their landmark air- craft had evolved directly out of testing conducted in a simple little wind tunnel they built in their Dayton bicycle shop. From these wind tunnel experiments in 1901, they garnered the empirical insights needed to design the first truly effec- tive flying machine, their breakthrough glider of 1902. The Wright brothers did not invent the wind tunnel, and the basic concept behind it predated their work by roughly 400 years. During the Renaissance, the brilliant technological dreamer Leonardo da Vinci recognized that air blown past a stationary object produced the same effect as the object itself moving at the same relative 240 Chapter 2: Building a Research Establishment speed through the air, the fundamental concept upon which wind tunnels operate. Da Vinci expressed this idea in his statement from the Codex Atlanticus, “As it is to move the object against the motionless air so it is to move the air against the motionless object.” Sir Isaac Newton later recognized this same principle. From these humble beginnings, the first person to apply the concept to practical aerodynamic research seems to have been Benjamin Robbins (1707–1751), a brilliant English mathematician who conducted a series of fundamental experiments on the ballistic properties of artillery projectiles. To evaluate the air resistance of different shapes, Robbins constructed a device known as a “whirling arm.” This apparatus consisted of a four-foot horizontal arm attached to a vertical spindle that was rotated by the force of a falling weight. Robbins mounted test shapes with similar cross-section areas on the end of his whirling arm, and found that the speed of the arm’s rotation varied considerably with objects of different profiles. From this he concluded that different shapes produced different amounts of air resistance, identifying the factor subsequently understood as aerodynamic “drag.”3 Following Robbins came John Smeaton (1724–1792), an English civil engineer interested in sources of power for practical applications. Smeaton used a whirling arm device of his own making to investigate the function of windmill sails. In 1759, he described his experiments and the elaborate apparatus used in his tests in a seminal paper presented to the Royal Society of London. In this report, he outlined the need for such equipment by noting a basic problem in aerodynamic research: relying solely on natural wind. “In trying experiments on windmill sails, the wind itself is too uncertain to answer the purpose; we must therefore have recourse to an artificial wind,” wrote Smeaton, adding that tests “may be done two ways: either by causing the air to move against the machine, or the machine to move against the air.” This principle of relative motion, the same observed earlier by da Vinci, proved to be the key to the future development of the wind tunnel. However, at the time, and indeed for the next hundred years, relatively few of Smeaton’s colleagues or successors either understood or accepted it.4 Nevertheless, there were some provident individuals intrigued with the inves- tigation of flight in the nineteenth century who utilized Smeaton’s whirling arm apparatus to understand aerodynamic principles. Sir George Cayley, for one, whose work outlined the basic shape of the airplane (see Chapter 1 of this volume), used a five-foot whirling arm that achieved tip speeds of up to twenty feet per second 3 John D. Anderson, Jr., provides a concise technical summary of the contributions of Leonardo da Vinci, Benjamin Robins, and other pioneers to the genesis of early aerodynamic concepts in A History of Aerodynamics and Its Impact on Flying Machines (Cambridge, England: Cambridge University Press, 1997), pp. 14–27 and 55–57. 4 On John Smeaton, see Anderson, A History of Aerodynamics, pp. 58–61 and 76–79. From the Wright Bicycle Shop to the Langley Full-Scale Tunnel 241 to measure the lift and drag properties of different wing shapes.5 Later in the cen- tury, some of the most important whirling arm experiments of the pre-flight era were conducted by Professor Samuel P.