Tests of N. A. C. A. 0009, 0012, and 0018 Airfoils in the Full-Scale Tunnel

An investigation was conducted in the N. A. C. A. full-scale wind tunnel to determine the aerodynamic characteristics of the N. A. C. A. 0009, 0012, and 0018 airfoils, with the ultimate purpose of providing data to be used as a basis for comparison with other wind-tunnel data, mainly in the study of scale and turbulence effects. Three symmetrical 6- by 36-foot rectangular airfoils were used. The Reynolds Number range for minimum drag was from 1,800,000 to 7,000,000 and for maximum lift, from 1,700,000 to 4,500,00. The effect of rounded tips was determined for each of the airfoils. Tests were also made of the N. A. C. A. 0012 airfoil equipped with a 0.20c full-span split flap hinged at 0.80c. Tuft surveys were included to show the progressive breakdown of flow near maximum lift.

Momentum surveys were made in conjunction with force measurements at zero lift as an aid in converting force-test data to section coefficients.