The technological audacity of the German missiles and jet fighters made American leaders resolve never again to lag behind in aeronautical research. To assure technical leadership, the Federal Government proposed a coordinated national plan of facility construction that would encompass not only NACA, but the Air Force, industry, and the universities as well. An early version of the so-called Unitary Plan envisaged 33 large transonic, supersonic, and hypersonic wind tunnels costing almost $1 billion. The Unitary Plan Act that was finally passed by Congress on October 27, 1949 was more modest in scale but still most impressive.
The Unitary Plan was spearheaded by the Air Force and to the Air Force went the cornerstone facility: a new aeronautical research center located near abundant hydroelectric power. Tullahoma, Tennessee, on the vast TVA hydroelectric grid, was selected as the site of the Air Engineering Development Center (AEDC), now known as the Arnold Engineering Development Center. Initial plans called for two 16-foot supersonic wind tunnels, a jet engine altitude test chamber, an aeronautical laboratory, and other support facilities. Dedicated by President Truman on June 25, 1951, AEDC has grown through the years to more than 40 test units, including 18 wind tunnels. Typical of the scale of AEDC construction is the Propulsion Wind Tunnel Facility, which consists of...
...two separate 16-foot tunnels spanning collectively the range from Mach 0.2 to Mach 4.75. Here full-scale fully operational turbojets and ramjets can be tested under conditions simulating aircraft and missile installations. In the early 1980s, AEDC's $440 million Aeropropulsion Systems Test Facility (ASTF) will go into operation, making AEDC the world's most complete aerospace ground test complex.
The original Unitary Plan included a NACA proposal for a separate National Supersonic Research Center, but this was dropped in view of the scope and depth of the Tullahoma complex. Instead, NACA's existing facilities were upgraded and repowered. Further, NACA's role in the development of aeronautics took a new direction under the Unitary Plan: industrial development work, that is, commercial aircraft, while AEDC focused on military aeronautics.
NACA had anticipated such an assignment and, in 1949, had set up a Project Office for the Unitary Wind Tunnels Program. This office was established at Ames, with John F. Parsons as Chief, reporting directly to the NACA Director. Each of the three NACA centers was involved. A large transonic/supersonic wind tunnel complex would be built at Ames;
Langley would have a new supersonic tunnel; and at Lewis there would be a large supersonic tunnel dedicated to propulsion system integration.