Stability of Rotating Threads

Abstract

STUDIES of rotating threads have disclosed some curious features with regard to the spiral sinusoidal forms which they assume. Two simple cases were first examined experimentally in order to explain anomalies in the third. The three cases are (1) a long freely hanging thread, attached to a horizontal rotating arm, supporting a spherical weight (M), (2) a thread similarly rotated about a horizontal axis, the thread passing over a light pulley at the loaded end, and (3) a thread withdrawn vertically at high speeds from its rest position closely coiled on a vertical cylindrical surface (that is, a full parallel-wound yarn bobbin) through an eyelet situated at an axial distance (L) above the surface.