A resume of the advances in theoretical aeronautics made by Max M. Munk
This is a 1926 technical report from the NASA Technical Reports Server summarizing theoretical aerodynamics work by Max M. Munk, written for engineers and aeronautics researchers. The two pictures are line diagrams: one shows a vortex-style force and velocity diagram around an elliptical wing section, the other shows streamlines of flow past a moving straight line. A designer might take from them the clean, schematic look of early aerodynamic diagrams, with thin black lines, dashed reference axes and arrowed flow paths.

