NACA: The Jet Age and Beyond

1946-1958

By Dwight Jon Zimmerman - June 29, 2015

The Bell Aircraft Corporation X-1-1 (#46-062) in flight. The X-1 series aircraft were air-launched from modified Boeing B-29 or B-50 Superfortress bombers. It was thought that the bright orange aircraft would be more visible to those doing the tracking during a flight. When NACA received the airplanes, they were painted white, which was an easier color to find in the skies over Muroc Air Field in California. This particular craft was nicknamed “Glamorous Glennis” by Chuck Yeager in honor of his wife, and is now on permanent display in the Smithsonian Institution’s National Air and Space Museum in Washington, D.C. NASA image

Though the NACA was responsible for many noteworthy contributions and advances to aircraft and flight during these years, three particularly stand out because of their overarching impact on the advancement of flight, both in aircraft and spacecraft: the swept-wing design, the area rule, and the blunt nose principle. The first two decreased drag, allowing for faster, higher, and more efficient flight. For the third, counter-intuitively its purpose was to increase drag, the purpose being to better dissipate heat. Swept-wing design and area rule became important building blocks in the development of transonic, supersonic, and hypersonic aircraft. The blunt nose principle proved the key for constructing spacecraft capable of safely transporting humans and photographic film, although originally envisioned for safely delivering intercontinental ballistic missile warheads into the atmosphere.

Ironically, though Bell engineers agreed that the swept wing was the future for supersonic flight, they chose not to incorporate it into the design of their X-1. Thus the world’s first supersonic airplane had a conventional straight-wing design.

The swept-wing design was the first of the three to emerge from the NACA, and the man credited with that breakthrough was Robert T. Jones, an aerodynamicist at NACA’s Langley lab. Self-taught, a college dropout, and something of a maverick, his start at NACA was a testament to talent trumping (or at least side-stepping) bureaucratic orthodoxy. He left the University of Missouri to sign on as a mechanic for the nationally famous barnstorming Marie Meyer Flying Circus (Charles Lindbergh was one of its stunt pilots). After it disbanded in 1928, he moved to Washington, D.C. The only job he could get during the Great Depression was that of elevator operator. He met a congressman and agreed to tutor him in physics and mathematics. The grateful congressman arranged for Jones to get a job in the Works Progress Administration program. His work attracted the attention of NACA Ames laboratory managers. Unable to hire him outright because the NACA position he was filling through the WPA required a college degree, Ames managers kept him employed through successive renewals of hire within the WPA program until Jones had enough experience to qualify for a higher position in NACA, one whose job description did not list the requirement of a college degree (presumably because only someone with one was capable of doing the work).

Jones had worked on subsonic swept-wing aircraft design in 1944. In early 1945 he discovered a breakthrough regarding how the swept-wing design could overcome the problem of compressibility as an aircraft approached Mach speed. On March 5, 1945, he issued a formal paper on his findings to NACA chiefs. To NACA Director of Research George W. Lewis he wrote, “I have recently made a theoretical analysis which indicates that a V-shaped wing traveling point foremost would be less affected by compressibility than other platforms. … In fact, if the angle of the V is kept small relative to the Mach angle, the lift and center of pressure remain the same at speeds both above and below the speed of sound.”

NACA research aircraft in 1953. Clockwise from bottom left: Bell X-1A, D-558-1, XF-92A, X-5, D-558-2, X-4, and X-3. NASA image

Jones went on to conduct model tests and additional delta wing configuration experiments. In late June 1945, he published a summary of his findings in NACA Technical Note Number 1033. It was in it that he proposed that supersonic planes being developed incorporate the swept-wing design. His findings received an additional boost when German aerodynamicists began arriving in the United States as a part of Operation Paperclip, which brought the bulk of German aircraft and rocket scientists, engineers, and designers to the country.

The result was that designers of Boeing’s B-47 tore up existing straight-wing blueprints and went back to the drawing board to create a swept-wing design so successful it became the model for the company’s subsequent bomber and airliner designs. North America’s straight-wing XP-86 jet fighter underwent a similar metamorphosis, becoming the F-86 Sabre, which would achieve fame in the Korean War.