A simple method for increasing the lift of airplane wings by means of flaps
A 1933 NASA Technical Reports Server record of a technical report on increasing airplane wing lift with flaps, aimed at aeronautical engineers. The pictures are engineering plots of lift coefficient against angle of attack and against drag, with multiple labelled curves for flap deflection angles and chord ratios, printed in black and white with a grid and a legend in the corner; a designer might take from them the clean graph style, the restrained line-and-marker vocabulary, and the sparse grid layout.
