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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.
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