Experiments on autorotation
A 1926 NACA technical report of experiments on autorotation, the self-sustained spinning of wings and bodies in an airstream, published by the NASA Technical Reports Server for aeronautical engineers and researchers. Its four pictures are engineering graphs of lift and drag coefficients, rotation ratios against lateral angle, and airfoil test curves for wind speeds of 9.15 to 18.3 metres per second, drawn in plain black lines on squared grids, offering a designer little beyond the look of technical plotting.
