Facing the Heat Barrier - NASA's History Office

Facing the Heat Barrier: A History of Hypersonics
values using theories that include only free-stream flow and ignore the boundary
layer. This emphasized anew the importance of the boundary layer in producing
hypersonic skin friction. 52
These results were fundamental, both for aerodynamics and for wind-tunnel
design. With them, the 11-inch tunnel entered into a brilliant career. It had been
built as a pilot facility, to lay groundwork for a much larger hypersonic tunnel that
could sustain continuous flows. This installation, the Continuous Flow Hypersonic
Tunnel (CFHT), indeed was built. Entering service in 1962, it had a 31-inch test
section and produced flows at Mach 10. 53
Still, it took a long time for this big tunnel to come on line, and all through the
1950s the 11-inch facility continued to grow in importance. At its peak, in 1961,
it conducted more than 2,500 test runs, for an average of 10 per working day. It
remained in use until 1972. 54 It set the pace with its use of the blowdown principle,
which eliminated the need for costly continuous-flow compressors. Its run times
proved to be adequate, and the CFHT found itself hard-pressed to offer much
that was new. It had been built for continuous operation but found itself used in a
blowdown mode most of the time. Becker wrote that his 11-inch installation “far
exceeded” the CFHT “in both the importance and quality of its research output.”
He described it as “the only ‘pilot tunnel’ in NACA history to become a major
research facility in its own right.” 55
Yet while the work of this wind tunnel was fundamental to the development of
hypersonics, in 1950 the field of hypersonics was not fundamental to anything in
particular. Plenty of people expected that America in time would build missiles and
aircraft for flight at such speeds, but in that year no one was doing so. This soon
changed, and the key year was 1954. In that year the Air Force embraced the X-15,
a hypersonic airplane for which studies in the 11-inch tunnel proved to be essential.
Also in that year, advances in the apparently unrelated field of nuclear weaponry
brought swift and emphatic approval for the development of the ICBM. With this,
hypersonics vaulted to the forefront of national priority.
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First Steps in Hypersonic Research
1 Anderson, History, pp. 251-255.
2 Wegener, Peenemunde, pp. 23-24, 167; Von Karman and Edson, Wind, p. 221.
3 Wegener, Peenemunde, pp. 22-23; Neufeld, Rocket, pp. 87-88.
4 Neufeld, Rocket, p. 87.
5 Wegener, Peenemunde, pp. 24-25; Shapiro, Compressible, pp. 203-04.
6 See, for example, Miller and Durant, Worlds, pp. 9, 17, 23.
7 Neufeld, Rocket, pp. 86, 88-91 (quote, p. 89). Zeppelin: Wattendorf, German, p. 19.
8 Wegener, Peenemunde, photos following p. 84.
9 Von Karman and Edson, Wind, pp. 218-19.
10 Dornberger, V-2, pp. 122-23, 127-28.
11 Hallion, Hypersonic, pp. xvi, xviii; Neufeld, Rocket, pp. 248-50, 283.
12 Neufeld, Rocket, pp. 250-51; Dornberger, V-2, p. 268.
13 Neufeld, Rocket, p. 250.
14 NASA SP-4303, pp. 77, 316, 330.
15 Wegener, Peenemunde, p. 70.
16 Lukasiewicz, Experimental, pp. 71-76.
17 Wegener, Peenemunde, pp. 70-71.
18 Neufeld, Rocket, p. 87; Wegener, Peenemunde, p. 24; Wattendorf, German, p. 4.
19 Wegener, Peenemunde, pp. 32, 75, photos following p. 84.
20 Wattendorf, German, p. 4.
21 Spaceflight, May 1973, pp. 166-71 (quotes, pp. 168, 170); Huxley, Brave, pp. 58, 59, 61.
22 Spaceflight, May 1973, pp. 166, 171-72 (quote, p. 166); Ley, Rockets, pp. 533-537.
23 Spaceflight, May 1973, pp. 171-72, 175-76; Ley, Rockets, pp. 533-34, 535; Ordway and Sharpe,
Rocket Team, pp. 327-28.
24 Spaceflight, May 1973, pp. 168-69.
25 Ley, Rockets, pp. 514-19, 524; Allen and Polmar, Downfall, pp. 103, 226.
26 Ordway and Sharpe, Rocket Team, p. 329; Jenkins, Space Shuttle, p. 2.
27 “Sänger.” MBB brochure, August 1986.
28 Boyne, Arrow, p. 139.
29 Speer, Inside, pp. 364-66.
30 Anderson, History, p. 435; NASA: SP-440, pp. 51-52; SP-4305, p. 467.
31 NASA: SP-440, p. 52; SP-4302, pp. 63-64.
32 AIAA Paper 79-0219, pp. 3-4.
33 Journal of the Aeronautical Sciences, July 1947. pp. 373-409 (Stack quote, p. 406).
34 Hermann, “Supersonic,” p. 439; Anspacher et al., Legacy, pp. 209-10.
35 Becker: Professional resume; NASA SP-4305, p. 54. R-2800 engine: “Dependable Engines”
(Pratt & Whitney).
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