The pressure distribution over a semicircular wing tip on an airplane in flight
This is a 1931 NACA technical note issued by the National Advisory Committee for Aeronautics, a United States aeronautical research body, reporting wind tunnel and flight measurements of pressure over a rounded wing tip for aircraft engineers. The pictures are plain line diagrams on white pages: isometric sketches of a wing planform with lettered chord stations and pressure curves drawn as outward spikes, plus one graph of rib moment coefficient against rib lift coefficient with straight lines fanning from a common point. A designer might take the clean technical line style, the tapering spike curves, and the thin grid-plot layout as models for diagrammatic annotation.
