The Denis-gruson Six-component Wind-tunnel Balance
A 1935 NACA technical memorandum by the NASA Technical Reports Server collection, issued for aeronautical engineers and researchers, describing the Denis-Gruson six-component wind-tunnel balance used to measure aerodynamic forces on models. The pictures are engineering line drawings of the balance's mechanical layout, wire suspension, and recording-drum optical lever, which a designer could use as a reference for diagrammatic mechanical schematics and measuring apparatus.
