Ground influence on airfoils
A 1921 aeronautical technical report on how the ground affects aircraft wings, issued through NASA's Technical Reports Server for engineers and researchers. Its pictures are plain black-and-white line graphs of lift and drag curves plotted against height above ground and angle of attack, with dashed and solid traces, grid lines and handwritten-style labels. A designer could borrow their stark chart grammar, dense grid structure and curve motifs for technical or scientific graphics.
