Tests of six symmetrical airfoils in the variable density wind tunnel
A 1931 technical report from the National Advisory Committee for Aeronautics, issued through the NASA Technical Reports Server, presenting wind tunnel test results for six symmetrical airfoil sections for engineers and aircraft designers. The pictures are plain engineering line graphs of drag, lift, and thickness against coefficients and angle of attack, set on gridded paper with dotted and solid curves. A designer could take from them the clean chart conventions of the period: thin black curves, labelled sections, and tabular gridlines.
