On the theory of hydrofoils and planing surfaces
This is a 1938 NACA technical memorandum, No. 845, issued by the National Advisory Committee for Aeronautics and distributed through the NASA Technical Reports Server, written for engineers and researchers studying hydrofoils and planing surfaces. Its pages are dense with numbered engineering figures: flow-line diagrams, lift and drag charts, and hydrofoil cross-section profiles. A designer could draw on the precise line-work of streamline grids, the stepped curve plots, and the small sequence of foil shapes for technical diagram styling.
