Comparison of Profile-drag and Boundary-layer Measurements Obtained in Flight and in the Full-scale Wind Tunnel
This is a 1939 NACA technical report, issued by the National Advisory Committee for Aeronautics, comparing boundary-layer and profile-drag measurements taken in flight against those from a full-scale wind tunnel. Its pictures are engineering line graphs of velocity ratio against chordwise position, with plotted data points, dashed and solid curves, and labelled height and Reynolds number keys. A designer could take from them the clean plotting conventions of mid-century technical figures: grid layouts, legend boxes, and paired marker symbols.
