Abstract
Spins may be divided into two classes, controlled and uncontrolled. In the controlled spin there is immediate response to control, while in the uncontrolled spin the response occurs some time later or even not at all after the controls have been moved. The problem is to avoid the accidental controlled or uncontrolled spins and to make the uncontrolled spin controllable. The author has made many observations of uncontrolled spins. The flights were carried on over a period of three years and show to a limited extent the independent effect of wing loading, center-of-gravity position, tail-surface plan form, tail-surface airfoil section, control-surface throw, and wing airfoil. The author indicates a number of conclusions from these observations, the first one of which is that wing loading is one of the major factors in uncontrolled spins.
