The Influence of Directed Air Flow on Combustion in Spark-Ignition Engine
This is a 1939 NACA technical report by the National Advisory Committee for Aeronautics, addressed to engine researchers, on how directed air flow shapes combustion in a spark-ignition engine. Its plates show flame-propagation photographs of the combustion chamber alongside schematic diagrams of valve and intake-passage positions and pressure-trace graphs. A designer might draw on the report's grid layouts of sequential frames, its dark-field photographs of glowing flame fronts, and its clean schematic line drawings of circular chambers and valves.
