An Elementary Study of the Spin: A Review of Existing Knowledge on a Problem of Ever‐Present Difficulty

There are several methods available for either preventing autorotation or reducing the autorotation speeds. There are special devices available such as slots or Schrenk slits, or the ailerons themselves may be used for this purpose. Once the designer has selected his plan form, etc., he can have a variety of aids to hinder the rotation of the machine about the longitudinal axis. The tendency to‐day is to eliminate such extraneous devices since the designer is loath to fit any arrangement which involves any complication such as moving parts or any increase in weight. He is content to rely for the most part on his experience in assessing the relative merits of various degrees of taper and tip sections, etc., and to assume that if he can dispose of wing dropping the autorotational characteristics of his wing will be satisfactory. This is not by any means a reliable guide at the coarser angles of incidence of a spin.