A High-speed Engine Pressure Indicator of the Balanced Diaphragm Type
This is a 1921 NASA technical report on a high-speed engine pressure indicator of the balanced diaphragm type, issued for aeronautical engineers and test staff. Its pictures are plain engineering graphics: pressure-against-crank-angle curves plotted on gridded axes with dashed and solid lines, and sectional mechanical drawings of a timer with hatched cut faces. A designer could take clean, restrained chart conventions, labelled axis schemes, and precise hatching for technical diagrams.
