A possible method for preventing the autorotation of airplane wings
This is a 1930 NASA technical report, here titled as a possible method for preventing autorotation of airplane wings, written for aeronautical engineers and researchers. The pictures are plots of lift coefficient against drag coefficient for several wing profiles at 30 m/s, and of flow ratio against angle of attack for autorotation tests at three airspeeds, with curves labelled a through f. A designer could take from them the clean line-and-marker chart style used for technical comparison of performance data.
