Filament-winding reverse helical

Reverse helical winding n. In filament winding, a pattern in which a continuous helix is laid down, reversing direction at each of the polar ends. It differs from biaxial compact, or sequential winding in that the fibers cross each other at definite equators, the number depending on the hehcal lead, with the minimum number of crossovers being three. 

There is the ovaloid netting system that is the natural result of the reversal of helical windings over the end of the vessel. The windings become thicker as they converge near the polar fittings. In order to resist internal pressure by constant filament tension only, the radius of curvature must increase in this region. It can also be equal to one half the cylinder radius when the helix angle a = 0°, and equal to the cylinder radius when a = 45°. The profile will also be affected by the presence of an external axial force. 

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