Recent researches in airship construction I : forces of flow on a moving airship and the effect of the control surfaces
This is a 1924 NACA technical memorandum, issued by the National Advisory Committee for Aeronautics as a report on airship aerodynamics, aimed at engineers and researchers. Its two pictures are engineering graphs and a dimensioned airship hull diagram: curved plots of control-surface coefficients against angle, and a side-elevation drawing with labelled section lines. A designer could take from them the clean, sparse plotting style of mid-century technical charts, with dashed and solid curve families, tick-labelled axes and a restrained monochrome palette.
