Effect of intake pipe on the volumetric efficiency of an internal combustion engine
This NASA technical report from 1929, issued as a NACA Technical Memorandum, presents engineering research on internal combustion engine intake pipes for an engineering audience of aeronautical and automotive researchers. The three pictures are graphs of entrance air velocity against crank angle, volumetric efficiency against engine speed with curves labelled by velocity, and pressure-volume indicator diagrams printed sideways on the page. A designer might take from them the plain line-graph conventions of early engineering reports, with labelled curves, dashed reference lines and stepped gridded axes.
