aviation comes of age
the creation of NACA
the development of air power
advocates of strategic bombing
Billy Mitchell and the bomber
the U.S. Air Corps
the start of air mail
the growth of airlines
Imperial Airways
the flying boats
the clipper ships
  a Russian experiment


The National Advisory Committee for Aeronautics (NACA)

From March 3, 1915 until October 1, 1958, the National Advisory Committee for Aeronautics (NACA) provided advice and carried out much of the cutting-edge research in aeronautics in the United States. Modeled on the British Advisory Committee for Aeronautics, the advisory committee was created by President Woodrow Wilson in an effort to organize American aeronautical research and raise it to the level of European aviation. Its charter and $5,000 initial appropriation (low even for 1915) were appended to a naval appropriations bill and passed with little notice. The committee's mission was to "direct and conduct research and experimentation in aeronautics, with a view to their practical solution."

John F. Victory (1892-1974) was the NACA's first employee and the only executive secretary it ever had.

The NACA was involved in virtually all areas of aeronautics. Initially consisting of 12 unpaid members, in its first decade it counselled the federal government on several aviation-related issues. These included recommending the inauguration of airmail service and studying the feasibility of flying the mail at night. During World War I, the NACA recommended creating the Manufacturers Aircraft Association to implement cross-licensing of aeronautics patents. The NACA proposed establishing a Bureau of Aeronautics in the Commerce Department, granting funds to the Weather Bureau to promote safety in aerial navigation, licensing of pilots, aircraft inspection, and expanding airmail. It also made recommendations to President Calvin Coolidge's Morrow Board in 1925 that led to passage of the Air Commerce Act of 1926, the first federal legislation regulating civil aeronautics. It continued to provide policy recommendations on the Nation's aviation system until its incorporation in the National Aeronautics and Space Administration (NASA) in 1958.

From its origins, the NACA emphasized research and development. Although the Wright brothers had flown successfully in 1903, by 1915 the United States lagged far behind European aviation capabilities, a situation many aviation advocates in the United States found galling. The United States trailed Europe in its accomplishments, its lack of organized research, and also in the amount of funds allocated to military aviation. To help resolve these problems, in 1917, the NACA established the Langley Memorial Aeronautical Laboratory in Virginia. This laboratory would become the most advanced aeronautical test and experimentation facility in the world.

Langley Laboratory's first wind tunnel, built in 1920.

By 1920, the NACA had emerged as a small, loosely organized group of leading-edge scientists and engineers that provided aeronautical research services equally to all. It had an exceptionally small headquarters staff that oversaw the political situation and secured funding for research activities.

Put into operation at Langley in 1922, the Variable Density Tunnel was the first pressurized wind tunnel in the world. It could achieve more realistic effects than any previous wind tunnel in predicting how actual aircraft would perform under flight conditions. Today it is a National Historic Landmark.

Its unpaid appointed governing committee made the committee one of the most non-traditional and non-bureaucratic organizations in Washington. Moreover, its small Langley Laboratory, with only 100 employees by 1925, conducted pure research, mostly related to aerodynamics, receiving advice and support from the headquarters director of research, Dr. George W. Lewis. Researchers could develop their own research programs along lines that seemed the most productive to them, handle all test details in-house, and conduct experiments as they believed appropriate. Their "Technical Notes" and "Technical Reports" presented their interim and final research findings. Old NACA hands believed that their independence from political pressures was partly the reason that NACA was the premier aeronautical research institution in the world during the 1920s and 1930s.

These five men were on the NACA's Propeller Research Tunnel engineering staff in 1928. Shown (left to right) are Fred Weick, Ray Windler, William Herrnstein, Jr., John Crigler, and Donald Wood. This group conducted the cowling research work that won the NACA its first Collier Trophy.

NACA was a valuable disseminator of information to designers and manufacturers. Research results distributed by the committee influenced American aviation technology, and its reports served as the basis for many innovations that were built into American civil and military aircraft.

The NACA cowling fitted on a Curtiss Hawk, 1928.

In 1925, NACA's director George Lewis launched construction of a wind tunnel large enough to accommodate a full-size fuselage with an engine. Fred Weick, the NACA's propeller expert, used this tunnel to study the relationship between engine cowlings and drag. The result was the low-drag streamlined cowling for aircraft engines, which all aircraft manufacturers adopted. This innovation would greatly reduce the drag that an exposed engine generated and would result in significant cost savings. The innovation won the NACA Collier Trophy for 1929. NACA engineers also demonstrated the advantages of mounting engines into the leading edge of a wing of multiengine aircraft rather than suspending them below, which manufacturers also quickly adopted.

Airfoil research was also a major focus. NACA engineers tested 78 airfoil shapes in its wind tunnels and in 1933 issued Technical Report No. 460, "The Characteristics of 78 Related Airfoil Sections from Tests in the Variable-Density Wind Tunnel." The authors of this report described a four-digit scheme that defined and classified the shape of the airfoil. The testing data gave aircraft manufacturers a wide selection of airfoils from which to choose. The information in this report eventually found its way into the designs of many U.S. aircraft of the time, including a number of important World War II-era aircraft.

A Vought O3U set up for tests using the full scale wind tunnel at Langley, completed in 1931.

The Langley laboratory continued to design new wind tunnels that added to its capabilities, building about a dozen tunnels by 1958. In 1928, the first refrigerated wind tunnel for research on prevention of icing of wings and propellers began operations. In 1939 the NACA constructed a new low-turbulence two-dimensional wind tunnel that was exclusively dedicated to airfoil testing. A transonic tunnel in the early 1950s provided data for Richard Whitcomb's research into supersonic flight.

In 1940, NACA established the Moffett Field Laboratory near San Francisco as an aircraft research laboratory. It was renamed Ames Aeronautical Laboratory for Joseph F. Ames, a chairman of NACA, in 1944. Also in 1940, Congress authorized the construction of an aircraft engine research laboratory near Cleveland, Ohio. Dedicated in 1943, it became Lewis Research Centre in 1948, named after George Lewis, former NACA director of aeronautical research. The NACA also established the Wallops Flight Centre on the eastern shore of Virginia in 1945 as a site for research with rocket-propelled models and as a centre for aerodynamic research. A temporary Langley outpost at Muroc, California, became a permanent facility known as the NACA Muroc Flight Test Unit in 1946. In 1949, it became the NACA High Speed Flight Research Station and in 1954, became independent from Langley.

NACA made a major contribution to aviation with its classification of airfoils. This shows the change in airfoil shape from the Wright brothers (1908) to more modern times (1944). Much of the data was obtained through wind tunnel testing.

Before the outbreak of World War II, NACA's research had both military and civil applications. During the war, however, its activity became almost exclusively military and its ties with industry also became much stronger. In 1939, the first industry representative, George Mead, president of United Aircraft Corporation, joined the executive committee as vice-chairman. Dozens of corporate representatives would visit Langley during the war to observe and actually assist in testing.

During the war, the NACA focused more on refining and solving specific problems rather than on advancing aeronautical knowledge. A major advance, however, was the development of the laminar-flow airfoil, which solved the problem of turbulence at the wing trailing edge that had limited aircraft performance.

The NACA also contributed to the development of the swept-back wing. In January 1945, Robert T. Jones, a NACA aeronautical scientist, formulated a swept-back-wing concept to overcome shockwave effects at critical Mach numbers. He verified it in wind-tunnel experiments in March and issued a technical note in June. His findings were confirmed when German files on swept-wing research were recovered and by German aerodynamicists who came to the United States at the close of the war.

High-speed flight research after the war was often a collaboration between the NACA and the U.S. Army Air Force. The first glide flight of the AAF-NACA XS-1 rocket research airplane took place in January 1946. Breaking of the sound barrier followed on November 14, 1947. Record flights by rocket planes by the military and the NACA probed the characteristics of high-speed aerodynamics and stresses on aircraft structures. NACA's John Stack led the development of a supersonic wind tunnel, speeding the advent of operational supersonic aircraft. He shared the Collier Trophy in 1947 with Chuck Yeager and Lawrence Bell for research to determine the physical laws affecting supersonic flight.

This photo displays typical high-speed research aircraft that made headlines at Muroc Flight Centre in the 1950s. Clockwise from lower left: the Bell X-1A, Douglas D-558-a Skystreak, Convair XF92-A, Bell X-5 with variable sweepback wings, Douglas D-558-II Skyrocket, Northrop X-4, and the Douglas X-3 in the centre.

At Lewis, NACA translated German documents on jet propulsion tests that became basic references in the new field of gas turbine research. Italian and German professionals came to Lewis to work with their American colleagues in these new aspects of flight research. To cope with continuing problems of how to cool turbine blades in the new turbojets, another German, Ernst Eckert, at Lewis laid the basic foundation for research into the world of heat transfer.

In December 1951, Richard T. Whitcomb verified his "area rule" in the NACA's new transonic wind tunnel. Useful in the design of delta-wing planes flying in the transonic or supersonic range, the rule stated that, to reduce drag, the cross-sectional area of the aircraft should be consistent from the front of the plane to the back. The resulting "Coke bottle" or "wasp waist" fuselage shape was contrary to the design customary at that time that had the cross-section much greater where the wings were attached to the fuselage. Designers quickly applied the supersonic area rule to the design of new supersonic aircraft.

In 1952, the NACA was already thinking about aircraft that went very high and had to re-enter the Earth's atmosphere at a high rate of speed, producing a great deal of heat. That year, H. Julian Allen of Ames conceived the "blunt nose principle," which suggested that a blunt shape would absorb only a very small fraction of the heat generated by the re-entry of a body into the Earth's atmosphere. The principle was later significant to intercontinental ballistic missile nose cone and NASA Mercury capsule development.

The NACA was also considering flight beyond the atmosphere. In 1952, the laboratories began studying problems likely to be encountered in space. In May 1954, the NACA came out in favour of a piloted research vehicle and proposed to the Air Force the development of such a vehicle. The NACA also studied the problems of flight in the upper atmosphere and at hypersonic speeds, which would lead to the development of the rocket-propelled X-15 research airplane.

The NACA ceased to exist on October 1, 1958. It was succeeded by the National Aeronautics and Space Administration (NASA), which was formed largely in response to Soviet space achievements. NACA became the nucleus of the new agency, and all NACA activities and facilities were folded into NASA. The major focus became space research, but aeronautics would remain as the first "A" in its name.