Investigation of a wing with an auxiliary upper part
This is a NACA technical memorandum from 1927, issued by the National Advisory Committee for Aeronautics and preserved through the NASA Technical Reports Server, written for aeronautical engineers and researchers. Its single picture is a set of profile diagrams of airfoil cross-sections labelled Fig. 1 through Fig. 3, with dimension letters marking the chord and thickness of a wing with an auxiliary upper part. A designer could take from it the clean, schematic linework and the lean, sectioned curves of aerofoil shapes as a source for minimal technical graphics.
