Torsion and buckling of open sections
A 1936 NASA technical report on torsion and buckling of open structural sections, compiled from aeronautical research for engineers and aircraft designers. Its pictures are plotted engineering charts: curves of buckling and torsion stress against section dimensions, with labelled 'buckling under axial load included' and 'disregarded' curves, and a few figure-numbered graphs of Euler buckling and torsion limits. A designer could take the restrained-versus-free comparison of curve families as a clean, minimal chart style for showing performance thresholds.
