The "navigraph"
This is a 1925 technical record from the NASA Technical Reports Server describing the navigraph, an instrument for plotting an aircraft's course against wind drift, with diagrams for aerial navigators and engineers. The three pictures are a vector triangle of airspeed, wind and drift, a route map annotated with wind speeds, and a photograph of the Le Prieur instrument beside a cabin view and a strip of recorded drift lines. A designer might take the clean dashed construction lines and labelled arrows as models for technical schematic diagrams.
