When aeronautics and space research is talked about today, the United States and NASA stand at the forefront of the discussion. But during World War I, the U.S. was lacking any coordinated effort in research and development on this front.
To remedy this fact, the National Advisory Committee for Aeronautics (NACA) was established to lay the ground work of what would become the most world renowned aeronautics research facility in the world.
An Agency in its Infancy
The need for an agency such as NACA was apparent years before its establishment, but political red tape stalled any progress. However, by 1915 the war effort mandated its creation, and on March 3 of that year the NACA officially came into existence.
Though the need for the NACA was apparent to those dealing directly in the arenas of science, technology and aviation, it was not a politically popular proposal. Therefore the necessary language for its creation was snuck into an otherwise innocuous Naval Appropriations Bill. The benefactors of the newly created agency, a band of 12 unpaid engineers and scientists were granted a $5,000 budget.
The Early Days of the NACA and the NACA Cowling
Initially the role of the NACA was to oversee and execute all aeronautical projects related to the war effort, but this would be later expanded to include the creation and implementation of technology to meet the needs of any civilian and military aviation problem.
By the 1920s the NACA had a host of testing facilities, including wind tunnels, engine test facilities and flight test facilities. This test bed allowed for the creation of the NACA cowling in 1927. The cowling is an aerodynamic fairing that allows for the creation of more streamlined engines and body shells, resulting in significantly lowered drag. An ancillary benefit of the technology is that it provides an engine cooling system. It is said that the development cost of this technology was returned many times over from the fuel savings it provided.
The NACA Airfoil
One of the most crucial and long lasting developments of the NACA was the creation of the NACA airfoil. Simply, an airfoil is the shape of a wing as seen edge on. The purpose, naturally, is to produce lift, allowing for a craft to realize flight.
Prior to the first NACA airfoils in the 1930s all airfoils were designed and then tested in wind tunnels to determine their characteristics and properties. But NACA researchers were able to develop mathematical equations to determine what shape of airfoil would be needed to achieve the desired dynamics.
Therefore NACA airfoils were designated by four (and later five, six and seven digit codes for more complex airfoils) describing the design properties, such as camber, length and angle of attack. The numerical code described the parameters used in the NACA airfoil equations used to determine the airfoil characteristics. The obvious benefits are lower development costs and faster implementation. The NACA airfoils are still used today in some of the most advanced aircraft in production.
The NACA Duct
One of the largest considerations in engine development is the cooling system. Engines create significant heat and therefore need to ventilate, usually by having cool air pass over them. When considering vehicles such as cars and airplanes, there is also the consideration of aerodynamical drag. Obviously this can effect fuel efficiency of the vehicle, but also its stability at high speeds.
To overcome this problem, NACA researchers developed the NACA duct (sometimes called the NACA scoop). The evolutionary design, created in 1945 allows for air to enter the vehicle (usually directly into the engine bay) with minimal effect on airflow around the bodywork of the vehicle. While seen on aircraft, ducts derived from NACA design principles are also seen on high performance cars.
The Area Rule for High Speed Flight
During the 1950s there was a push to develop supersonic aircraft. However, there was difficulty in getting around aerodynamic problems. Namely the airflow around the aircraft did not behave as expected.
Even at subsonic speeds above about 70% of the speed of sound the craft would begin to experience significantly higher drag and expected. The reason was that at those speeds the air flowing around the craft would no longer behave as an incompressible fluid, essentially because the air could not get out of the way fast enough.
Several German and American researchers arrived at this conclusion in the 1940s and developed rules to govern wing and fuelsolodge design. However, implementation of these rules was never completed. Then, Richard T. Whitcomb, while working at the NACA in 1952 arrived at the conclusions drawn by his predecessors and laid out the "area rule" which took into consideration the consequences of the 3-dimensional design of the wings. (Previously, aerodynamic characteristics were only considered on the 2-dimensional cross-sections of the wings.)
As a result, Whitcomb realized that the cross-sectional area of the wings, tail and fuelsolodge had to be considered when designing high-speed aircraft. The so-called Whitcomb area rule established a means of calculating the area bounds of aircraft and is still used today.
The Creation of NASA
By 1958 it had become clear that an organization designed to explore the possibilities of space was needed. To this end the National Aeronautics and Space Administration (NASA) was created. But it was with the understanding that the NACA would form the basis for this new entity, so the facilities, research and personnel were transfered to NASA.
Essentially NASA was a re-boot of the NACA with a new and more focused goal. While NASA would continue doing much of the work that the NACa had begun, it would also seek to develop a new program for space exploration and discovery.