The development of airfoil sections began in the late 1800’s. Before the development, it was known that flat plate would produce lift when set an angle of incidence, however faithful to see that the curvature that resembled bird wings would produce more elevation and more efficient. In 1884, H.F Philips patented a series of airfoil shapes after testing them in one of the earliest wind tunnels. In 1920’s, a wide range of airfoils was developed based on primarily on trial and error. Figure 9, shows the example of the airfoils. Figure 9: Example of airfoil developed in 1920’s
In the early 1930’s, Eastman Jacobs created a family of airfoils known as the NACA Sections. NACA sections are based on the airfoil geometry which is characterized by