Rotary drum for video tape recorder

摘要

A surface of an upper rotary drum of a video tape recorder is machines such that it has a surface roughness in a range from 1 mu m to 2 mu m so as to enable a releasing of air on the upper rotary drum surface uniformly whereby a thickness of an air film between a magnetic tape and a head is uniformly reduced without affecting the tape running. The surface may be grooved concurrently with the roughened surface. A window is formed in rotary drum for receiving at least one magnetic head.