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Chapter 2: Fundamental ThoughtsLet us pick up the thread of aeronautical engineering history from Chap. 1. After Orville and Wilbur Wright's dramatic public demonstrations in the United States and Europe in 1908, there was a virtual explosion in aviation developments. In turn, this rapid progress had to be fed by new technical research in aerodynamics, propulsion, structures, and flight control. It is important to realize that then, as well as today, aeronautical research was sometimes expensive, always demanding in terms of intellectual talent, and usually in need of large testing facilities. Such research in many cases either was beyond the financial resources of, or seemed too out of the ordinary for, private industry. Thus, the fundamental research so necessary to fertilize and pace the development of aeronautics in the 20th century had to be established and nurtured by national governments. It is interesting to note that George Cayley himself (see Chap. 1) as long ago as 1817 called for "public subscription" to underwrite the expense of the development of airships. Responding about 80 years later, the British government set up a school for ballooning and military kite flying at Farnborough, England. By 1910, the Royal Aircraft Factory was in operation at Farnborough with the noted Geoffrey de Havilland as its first airplane designer and test pilot. This was the first major government aeronautical facility in history. This operation was soon to evolve into the Royal Aircraft Establishment (RAE), which today is still conducting viable aeronautical research for the British government.
In the United States, aircraft development as well as aeronautical researchlanguished after 1910. During the next decade, the United States embarrassingly fell far behind Europe in aeronautical progress. This set the stage for the U.S. government to establish a formal mechanism for pulling itself out of its aeronautical "dark ages." On March 3, 1915, by an act of Congress, the National Advisory Committee for Aeronautics (NACA) was created, with an initial appropriation of $5000 per year for 5 years. This was at first a true committee, consisting of 12 distinguished members who were knowledgeable about aeronautics. Among the charter members in 1915 were Professor Joseph S. Ames of Johns Hopkins University (later to become president of Johns Hopkins) and Professor William F. Durand of Stanford University, both of whom were to make major impressions on aeronautical research in the first half century of powered flight. This advisory committee, NACA, was originally to meet annually in Washington, District of Columbia, on "the Thursday after the third Monday of October of each year," with any special meetings to be called by the chair. Its purpose was to advise the government on aeronautical research and development and to bring some cohesion to such activities in the United States.
The committee immediately noted that a single advisory group of 12 members was not sufficient to breathe life into U.S. aeronautics. Their insight is apparent in the letter of submittal for the first annual report of NACA in 1915, which contained the following passage:
There are many practical problems in aeronautics now in too indefinite a form to enable their solution to be undertaken. The committee is of the opinion that one of the first and most important steps to be taken in connection with the committee's work is the provision and equipment of a flying field together with aeroplanes and suitable testing gear for determining the forces acting on full-sized machines in constrained and in free flight, and to this end the estimates submitted contemplate the development of such a technical and operating staff, with the proper equipment for the conduct of full-sized experiments.
It is evident that there will ultimately be required a well-equipped laboratory specially suited to the solving of those problems which are sure to develop, but since the equipment of such a laboratory as could be laid down at this time might well prove unsuited to the needs of the early future, it is believed that such provision should be the result of gradual development.
So the first action of this advisory committee was to call for major government facilities for aeronautical research and development. The clouds of war in EuropeWorld War I had started a year earlier-made their recommendations even more imperative. In 1917, when the United States entered the conflict, actions followed the committee's words. We find the following entry in the third annual NACA report: "To carry on the highly scientific and special investigations contemplated in the act establishing the committee, and which have, since the outbreak of the war, assumed greater importance, and for which facilities do not already exist, or exist in only a limited degree, the committee has contracted for a research laboratory to be erected on the Signal Corps Experimental Station, Langley Field, Hampton, Virginia." The report goes on to describe a single, two-story laboratory building with physical, chemical, and structural testing laboratories. The building contract was for $80,900; actual construction began in 1917. Two wind tunnels and an engine test stand were contemplated "in the near future." The selection of a site 4 mi north of Hampton, Virginia, was based on general health conditions and the problems of accessibility to Washington and the larger industrial centers of the east, protection from naval attack, climatic conditions, and cost of the site.
Thus, the Langley Memorial Aeronautical Research Laboratory was born. It was to remain the only NACA laboratory and the only major U.S. aeronautical laboratory of any type for the next 20 years. Named after Samuel Pierpont Langley (see Sec. 1.7), it pioneered in wind tunnel and flight research. Of particular note is the airfoil and wing research performed at Langley during the 1920s and 1930s. We return to the subject of airfoils in Chap. 5, at which time the reader should note that the airfoil data included in App. D were obtained at Langley. With the work which poured out of the Langley laboratory, the United States took the lead in aeronautical development. High on the list of accomplishments, along with the systematic testing of airfoils, was the development of the NACA engine cowl (see Sec. 6.19), an aerodynamic fairing built around radial piston engines which dramatically reduced the aerodynamic drag of such engines.
In 1936, Dr. George Lewis, who was then NACA Director of Aeronautical Research (a position he held from 1924 to 1947), toured major European laboratories. He noted that NACA's lead in aeronautical research was quickly disappearing, especially in light of advances being made in Germany...