The effectiveness of tension control was investigated by measuring the internal strain and the shape of end faces of two yarn packages. One package was formed using the theoretical tension curve whereby stress is the same for all yarn layers. The other package was formed under constant winding tension. Anisotropy, bulge, and cob-webbing of the end faces were smaller for the package formed under controlled tension rather than constant tension. The distribution of internal strain and unwinding tension was smaller for the package formed under the controlled winding tension than for the package formed under constant winding tension. 2 refs.