Friday, June 30, 2017

Pitch angle = pitch angle

In ordinary-lay compound helices, a stable configuration tends to occur when the pitch angle of the major helix equals the pitch angle of the minor helices. For example, the case below of a 3x3 compound helix: the 70 degree pitch angle (measured from the equatorial plane) of the major helix matches that of the three 3-ply strands. The frequency ratio in the 3x3 compound helix  is 2:1. The equality of pitch angles together with the counter-rotation of the ordinary lay, make exposed strands look like they run straight along the rope.
3-ply strands with 70-degree pitch.

Compound 3x3 helix with 70-degree pitch.

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