The aerodynamic wind vane and the inherent stability of airplanes
This is a 1931 NACA technical memorandum from the NASA Technical Reports Server, a government aeronautical research report on airplane stability issued for engineers and aerodynamicists. The pictures show wind tunnel test setups where model aircraft are mounted on rods and frames and photographed in sequence. A designer could take from them the stark grid of numbered photo panels, the thin wire struts holding a suspended model, and the dim, grey, instrument-like tone of mid-century engineering documentation.
