Induced drag of multiplanes
A 1924 NASA Technical Reports Server scan of a technical study on induced drag in multiplane aircraft wings, presumably written for aeronautical engineers and researchers. Its pictures are plain graphs and line diagrams: curves plotted on grid paper for coefficients of mutual influence and drag ratios, and a streamline sketch of flow disturbance around two bodies, which a designer might take as an example of clean, data-driven technical charting in black ink on white.
