N.A.C.A. Recording Air Speed Meter
This 1921 technical report from the National Advisory Committee for Aeronautics, a US government aeronautics research body, documents a recording air speed meter for aircraft instrumentation. The photographs show laboratory apparatus: a set of finely ruled scales, a smooth oscilloscope-style trace of a damped oscillation, and two metal instrument housings with mounted fittings. A designer might take from them the look of early precision measurement equipment, with dense graduated markings and clean sinusoidal traces.
