Originally Posted by
ShyTorque
Whether a cable birdcages surely depends on the total number of turns applied to it, rather than how quickly turns are applied.
Bird caging the cable is a very bad thing because it may jam the winch. If the cable is cut, that's the end of winching for the day. Especially bad if there is more than one person to be brought up on the wire. Hence the swivel and 'tag' line method.
Real question may be how many twists the torque developed by stretcher will induce on the cable before the opposing torque from the twisted cable matches, not whether the cable catastrophically fails.
A quick experiment using some ~0.1" twisted cable as a model suggests quite a few twists.
By the time the torques match the stretcher will have accumulated significant angular momentum so will continue to spin for a while before eventually stopping, at which time the counter torque from cable would be higher than downwash induced toque so the stretcher would start spinning in the opposite direction for a while.
Reminds me of a child's toy using twisted strings to spin a large button in the middle, once going wind/unwind to other limit, rinse and repeat.
So basically you might change a bad ride into a truly bad ride, I suspect high constant G is likely better than continuously changing G.
Engineering 101 "you cant push a string" probably applies here. (Unless it is wet and frozen)
BTW: My use of 'torque' in above may/may not be pedantically correct but I believe it is understandable.