NASA_NTRS_Archive_19930091179
A 1923 NASA Technical Reports Server document, one of a series of aeronautical technical reports issued for engineers and researchers, presenting stress and force analyses for rigid airships and airship hulls. The pictures are plain line diagrams: force polygons with labelled vectors and cable stress lines, a schematic of a hull profile with force arrows, and a fold-out drawing of a rigid airship with bending moment and envelope curves. A designer might take from them the clean, labelled vector-diagram style, with thin black lines, dashed centre lines and small text callouts.
