Device for measuring sound in airplane engines
This is a 1924 NASA Technical Reports Server record of a device for measuring sound in aircraft engines, made for engineers and researchers. The pictures are plain line drawings: two oscilloscope-style waveform traces labelled Fig.1 and Fig.2 showing a smooth wave against noisy, jagged signals, and below them a wiring schematic with coils, a galvanometer, resistors and a battery. A designer could take the clean technical diagram style and the contrast between ordered and chaotic traces for minimal line work.
