Power characteristics of fuels for aircraft engines
A 1920 technical report from the National Advisory Committee for Aeronautics, published as part of its annual report and produced for aircraft engineers and researchers. Its pictures are plain line graphs with gridded axes, plotting fuel consumption against power, altitude and performance curves in ruled, data-driven black and white. A designer might take from them the clean, schematic chart style of early engineering documentation, with its labelled axes, tick marks and stepped curve lines.
