The N.A.C.A. and its military patrons in the supersonic era, 1940-1958.

Author:Gorn, Michael H.
Position:National Advisory Committee for Aeronautics
 
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Old Tensions in the Postwar World

During the decade before America's entry into World War II, the proportion of Research Authorizations pursued for the armed forces by the National Advisory Committee for Aeronautics (N.A.C.A.) doubled from 44 percent in 1930 to 88 percent in 1940. Yet, despite the increased contact that this upsurge suggests, longstanding tensions continued between Army aviation and the N.A.C.A. / Navy alliance. During World War II, overt signs of these differences receded due to the pressures of wartime research. But war could not suppress entirely the underlying feelings that persisted. On the one hand, the N.A.C.A.'s engineers at the Langley Laboratory had grown confident, perhaps even cocky, about the superiority of their research, bolstered by increased national and international recognition. On the other hand, many Army Air Forces officers chafed at this state of affairs, still hoping to pursue Billy Mitchell's vision of an independent air arm outfitted with its own, full-scale research establishment.

No doubt unintentionally, the Chief of the Army Air Corps, Maj. Gen. Henry H. "Hap" Arnold, contributed to this latent sense of ill-will. In 1938, Arnold learned from Charles Lindbergh, then touring Germany, that the Luftwaffe had developed military aircraft capable of flying at more than 400 miles per hour. Arnold spoke to the N.A.C.A. director, George Lewis, to see whether this claim had substance. Lewis admitted that the technology to fly at that speed and faster existed, but at the same time he reminded the general that the N.A.C.A. had always responded to--and could not be expected to anticipate--the military's requests for research. Arnold was greatly dismayed and could not understand how Lewis could have known about a breakthrough of such magnitude and not commit Langley to investigate it? Arnold also expressed dissatisfaction with the N.A.C.A. for failing to act expeditiously to perfect the Whittle turbine engine, a technology that he had brought home personally to the U.S. from the U.K. But in a broader sense, the two men simply represented the interests of their respective institutions. Arnold was preoccupied with war planning and projecting the likely capabilities of potential enemies, while Lewis concentrated on engineering research on a broad front, for civilian and military purposes. In practice, however, it made for a tense relationship.

Perhaps as a result of these encounters, Arnold lost confidence in the N.A.C.A. and looked to alternate sources to fill the perceived deficiency. For the time being, he accommodated the situation by cultivating aircraft industry leaders and by relying on the Army Air Forces' own research team. He also sought the counsel of eminent university scientists. Professor Theodore von Karman of Caltech emerged as Arnold's most trusted technical advisor. Near the end of the war, Arnold asked the Hungarian-born scientist to form a team comprising the best minds he could enlist. Additionally, he asked von Karman to gather the most advanced scientific ideas and equipment he could find from German and other national aeronautical laboratories. Finally, Arnold invited von Karman to advise him about the direction of postwar American air power research. Karman's subsequent report, entitled Toward New Horizons did just that, and Arnold and his successors enacted two important structural changes implicit in the report: they established a permanent, peacetime UASF Scientific Advisory Board to provide ongoing, high-level technical recommendations; and they initiated an organization devoted to promoting engineering and science, known originally as the Air Research and Development Command. Consequently, when the United States Air Force (USAF) emerged as a separate military service in September 1947, it had already laid the cornerstone for its own in-house research establishment.

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Thus, before and during World War II, Hap Arnold contributed to the long history of mistrust between the N.A.C.A. and Army aviation. In fact, the tensions deepened as both sides geared up for the ascent on supersonic flight, the next great milestone in aeronautics.. Although the formal pursuit of Mach 1 began during World War II, the N.A.C.A.'s research interest in high speed flight dated at least from 1925. At that time, the future Associate Administrator of NASA, Dr. Hugh L. Dryden, co-published with Dr. Lyman Briggs a seminal NACA Technical Report entitled "Aerodynamic Characteristics of Airfoils at High Speeds." Their article predicted the pressure effects associated with supersonic travel. Then, during the late 1920s and early 1930s, Langley engineers Eastman Jacobs and John Stack extended Dryden and Briggs' research. Using a very small-scale high speed wind tunnel and a process known as Schlieren Photography, they made images of air being compressed as a research aircraft approached Mach 1. Unfortunately, further wind tunnel work failed because the higher speeds caused incidental turbulence inside of the bigger tunnels, preventing accurate readings. As an alternative, Stack (who had already designed an experimental aircraft for the purpose) lobbied George Lewis to initiate a research airplane project with the goal of investigating transonic flight the transition from subsonic to supersonic speed. Lewis agreed in principle, but because he lacked the resources, told Stack to pursue the project informally, at least for the time being. Meanwhile, during World War II the N.A.C.A.'s engineers and pilots accumulated additional data on transonics and supersonics by mounting small airfoils vertically on the wings of a P-51D military aircraft and flying the plane in steep dives. These maneuvers created high speed air flows on the test wings. (1)

By the time George Lewis discussed Stack's project with the military, the sharp differences between Army aviation objectives versus the Navy/N.A.C.A position had already hardened into dogma. Army Major Ezra Kotcher did much to influence the debate. A civilian engineer later assigned to active duty at the Engineering Division at Wright Field, he (like Stack) pressed his superiors for a research airplane. But there the similarity ended. Kotcher wanted to exceed Mach 1 in the shortest time possible, using a rocket-powered aircraft. Stack pushed for a jet-powered research vehicle capable of transonic flight. Like the differences between Arnold and Lewis at their level, the contrast between Kotcher and Stack stemmed from their institutional orientations. In the midst of a global war, the Army Air Forces and Kotcher sought powerful new weapons capable of making an immediate impact on the tide of battle. Stack and the N.A.C.A., whose research concentrated more on underlying causes rather than immediate results, naturally preferred jet to rocket propulsion because it had the capacity to fly longer and collect far more data.

Ultimately, this division led to two separate but mutually dependent programs. By June 1944 the Army had decided to pursue a rocket-propelled experimental aircraft capable of flying "at least 650 mph at about 20,000 feet altitude." The Navy and the N.A.C.A. had cast their lot with a high-speed, four engine turbojet research vehicle. In October 1944, George Lewis announced that the N.A.C.A. planned to share its blueprints for experimental aircraft with the Army and the Navy, "as the NACA had no intentions of making a final design or constructing such an airplane." He might have said, more accurately, that far from having no intentions, the N.A.C.A. had no money.

By the start of 1945, Army officials began the search for a contractor to build a prototype along the lines laid out by Kotcher (with some important N.A.C.A. design suggestions). Kotcher found no interest among the manufacturers, except for Bell Aircraft of Buffalo, New York. In March, Bell agreed to produce three Experimental [X-1] vehicles. Meanwhile, the N.A.C.A. and Stack called on their old friends in the Navy's Bureau of Aeronautics and Douglas Aircraft. This link dated back decades, personified in the friendship between former Bureau of Aeronautics Chief of Design Jerome Hunsaker (see note 2) and his one-time pupil at M.I.T., Donald Douglas. But in addition to honoring old alliances, the Navy considered practical factors as well. It agreed to fund a transonic research airplane because it had not pursued much related research on its own, and also because the N.A.C.A. discoveries promised dividends that could be applied to the future naval air fleet. No less important was the fact that the sponsorship served to counter Army claims of preeminence in the field. Thus, while the Army negotiated with Bell, between February and April 1945 the Navy and Douglas (advised by the N.A.C.A.) laid the groundwork for their prototypes. In June, they signed an agreement for the fabrication of two models: the Douglas D-558-1 and D-558-2; respectively, the Skystreak and the Skyrocket. In all, the Navy committed itself to purchase six aircraft, all of them initially configured as turbojets, two of which would be modified later for hybrid turbojet/rocket propulsion. (2)

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Flight research on the Bell X-1 and the Douglas D-558s stirred contention between the...

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