Effect of air-fuel ratio on detonation in gasoline engines
A 1938 NASA technical report on how fuel-air ratio affects detonation and performance in gasoline engines, written for engine researchers and aeronautical engineers. Its pictures are plain graphs of temperature, fuel consumption, flame speed and octane number plotted against fuel-air ratio, with curves, dashed guide lines and a marked correct-mixture line; a designer could borrow their clean technical chart layout, grid lines and axis labelling.
