Comparing maximum pressures in internal combustion engines
A 1922 technical report from the NASA Technical Reports Server, a dated engineering document on measuring maximum pressures in internal combustion engines, apparently written for engine researchers and aeronautical engineers. Its two pictures are plain line drawings: a sectioned spark plug shell with an aluminum diaphragm and brass collars, a wiring or sensor arrangement labelled A and B, and a graph of diaphragm thickness against time. A designer could take their clean, labelled technical diagram style, with lettered call-outs and a simple plotted curve.
