The Theory of the Strandgren Cyclogiro
This NACA technical memorandum, issued by the National Advisory Committee for Aeronautics, is a 1933 engineering report on the theory of the Strandgren cyclogiro, a rotor-based aircraft, written for aeronautical engineers and researchers. Its pictures are plain black-and-white line diagrams of vector forces, rotor circles, and angle-of-incidence geometry, with a few pages of mechanical linkage sketches and graphs; a designer could draw on their clean technical schematic style and the dense labelled diagram layouts.
