Mechanical control of airplanes
A 1929 technical report plate from NASA's Technical Reports series, with the heading Mechanical Control of Airplanes, compiled for aeronautical engineers and researchers. The page is a grid of numbered photographs and line diagrams of aircraft control mechanisms, including a control column, rudder bar, cockpit instrument panels and linkage drawings. A designer could take its dense, grey, labelled plate layout as a model for a schematic or technical-diagram aesthetic.
