The processes in spring-loaded injection valves of solid injection oil engines
A 1934 NASA technical memorandum, issued as NACA Technical Memorandum No. 706 (per the running header), studying spring-loaded fuel injection valves in solid-injection oil engines. The pictures are engineering charts, graphs and vector diagrams of valve stem travel, pressure against crank angle, and natural frequency curves plotted on logarithmic grids. A designer might take from them the clean, dense line-graph style of mid-century technical plates, with labelled curves, hatched areas and tick-marked axes.
