General instability criterion of laminar velocity distributions
A NACA technical memorandum from 1936 on the general instability criterion of laminar velocity distributions, issued by the National Advisory Committee for Aeronautics for aeronautical researchers and engineers. Its pictures are plain line graphs and schematic diagrams: curves of velocity against distance, stability-parameter plots on gridded axes, and simple boundary-layer sketches with labelled axes and Greek symbols. A designer might borrow the clean grid-and-curve diagram style and the minimal labelled-axis vocabulary.
