23 See C. Fayette Taylor, "Aircraft Propulsion: A Review of the Evolution of Aircraft Powerplants," Report of the Smithsonian Institution for 1961 (Washington, 1962), 245-298.
24 The best-known of these advisory groups was the so-called von Kármán Committee, established late in 1944 at the direction of Henry H. Arnold, Commanding General of the Army Air Forces, and headed by Theodore von Kármán, of the California Institute of Technology. After surveying wartime achievements in aeronautical science and rocketry, the panel of scientists published its findings in August 1945 and its recommendations in December. While giving full credit to the German accomplishments in rocketry, the von Kármán committee concluded that jet propulsion offered the key to "air supremacy," and that progress toward long-range ballistic missiles should come through the development of air-breathing pilotless aircraft. The philosophy embodied in these 14 reports was to guide Air Force thinking for almost 10 years. See Army Air Forces Scientific Advisory Group, Toward New Horizons: A Report to General of the Army H. H. Arnold (14 vols. [Washington], 1945). For a retrospect of the findings of the committee, see Hugh L. Dryden, "Toward the New Horizons of Tomorrow: First Annual ARS von Kármán Lecture," Astronautics, XII (Jan. 1963), 14-19. Dryden served as deputy scientific director to von Kármán on the committee.
25 Levine, "U.S. Aeronautical Research Policy," 91-97; Hunsaker, "Forty Years of Aeronautical Research," 267-268.
26 The unitary plan was designed to provide dispersed NACA-Air Force wind-tunnel facilities characterized by a minimum of overlap and a maximum of variety. Five new supersonic wind tunnels were constructed, one at each of the NACA laboratories and two at a new Air Force installation, the Arnold Engineering Development Center at Tullahoma, Tenn. See Manual for Users of the Unitary Plan Wind Tunnel Facilities (Washington, 1956); and Alan Pope, Wind-Tunnel Testing (2 ed., New York, 1954).
27 Axel T. Mattson, interview, Houston, July 2, 1964; Gray, Frontiers of Flight, 330-359; Frank Waters, Engineering Space Exploration: Robert R. Gilruth (Chicago, 1963), 38-39: "History of NACA Transonic Research," Langley Aeronautical Laboratory, undated copy in Archives of the Manned Spacecraft Center (MSC), Houston. Unless otherwise indicated, originals or copies of all primary materials cited in this work are located in the MSC Archives. The Langley engineers also pursued their transonic investigations with a method devised in 1944 by Gilruth, whereby small models of wings or complete aircraft were attached to the upper wing surface of an airplane, thus em- ploying the accelerated airflow over the wing surface for studying the aerodynamic characteristics of the model at transonic speeds.
28 Perry, "Antecedents of the X— 1," 18-20; Kenneth S. Kleinknecht, “The Rocket Research Airplanes,” in Eugene M. Emme, ed., The History of Rocket Technology: Essays on Research, Development, and Utility (Detroit, 1964), 193-198; Hunsaker, “Forty Years of Aeronautical Research,” 268, 269; Gray, Frontiers of Flight, 334-336; Ley, Rockets, Missiles, and Space Travel, 419-432. Because of the fear that the X-l, operating with an entirely new rocket powerplant, might not be ready as early as planned, the NACA-Air Force-Navy group concurrently developed a jet-propelled research airplane, the Douglas D-558-1. This was also in keeping with NACA’s original conviction, shared by the Navy, that the first research aircraft would be turbojet-powered.
29 Kleinknecht, “Rocket Research Airplanes,” 199-204; Ley, Rockets, Missiles, and Space Travel, 424-426; Charles V. Eppley, The Rocket Research Aircraft Program, 1946-1962 (Edwards Air Force Base, Calif., 1962), 1-25; Hunsaker, “Forty Years of Aeronautical Research,” 269; James A. Martin, “The Record-Setting Research Airplanes,” Aeronautical Engineering Review, XXI (Dec. 1962), 49-54; Walter C. Williams and Hubert M. Drake, “The Research Airplane: Past, Present, and Future,” Aeronautical Engineering Review, XVII (Jan. 1958), 36-41; Walter T. Bonney, “High-Speed Research Airplanes,” Scientific American, CLXXXIX (Oct. 1953), 36-41. For the experiences of two rocket-airplane test pilots, as well as for useful treatments of the postwar research aircraft series, see A. Scott Crossfield and Clay Blair, Always Another Dawn (Cleveland, 1960); and William Bridgeman and Jacqueline Hazard, The Lonely Sky (New York, 1955).
