Wind-Tunnel Investigation of an NACA 23012 Airfoil with Various Arrangements of Slotted Flaps
This is a 1939 NACA technical report from NASA's Technical Reports Server describing wind-tunnel tests of an NACA 23012 airfoil fitted with slotted flaps in several arrangements, written for aeronautical engineers. Its pictures are dense engineering charts with grid backgrounds, plotting lift, drag and pitching-moment coefficients against angle of attack as thin hand-drawn curves in black ink, with figure captions along the bottom. A designer might take the restrained grid-and-curve layout, the tight vertical stacking of plots, and the sparse monochrome palette as a model for technical diagram composition.
