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## Re: [TowerTalk] Rohn Torque Bar confusion

 To: , "TowerTalk" Re: [TowerTalk] Rohn Torque Bar confusion "Tom Rauch" Tom Rauch Tue, 3 Aug 2004 21:09:23 -0400
 ```> IMO, if you compare the above to a six point torque arm system, well, there > really is no comparison. > > Keith But no one is saying they are equal Keith. I see a serious flaw in the idea a guying system does nothing to reduce twist. That idea only would be true if the guyline attached to the center axis of the tower. Consider a spoked wheel such as on a bicycle or even the drive wheel of a motorcycle or car with wire wheels. If the guyline does not resist twist, why do wire wheels resist huge amounts of torque without serious deflection? The reason is pretty simple. When the tower twists all three guylines have to reach a longer distance, tension increases a large amount. (You could view the tower as a wheel.) All three guylines, when the tower starts to wrap up, add force that opposes any twist. That's because the guylines are no longer in line with the center line of the tower. Each guyline adds an equal opposing force to any twist. Now that isn't exactly like a wire wheel with 50 spokes, but it still is a significant force when the twist tries to pull the guyline an extra inch or two! As a matter of fact, this is why tower with heavy insulators in guylines feel so "twisty". They have more sag to suck up out of the guyline, so the tower can twist and wobble more than a guyline with less sag. If a tower with a radius of one foot is extended to two feet in radius by the addition of a torque arm, the same increase in guyline end spacing would cause twice as much resistance to torque. The primary difference between a torque arm and a six wire star bracket is the star bracket already starts with the wires "deflected" from being in line with the center, so the initial movement is much less for a given increase in guy tension. The fact it is six lines doesn't help, because three are going slack while three are tightening. That's how it looks to me in my head-cad. I'm sure there is someone who can put numbers on this. The problem isn't that complex. I do absolutely know the idea guylines do nothing to resist twist is wrong, because I can't twist my tower that sits on a greased ball at the base insulator and it has NO torque arms of any type. 73 Tom _______________________________________________ See: http://www.mscomputer.com for "Self Supporting Towers", "Wireless Weather Stations", and lot's more. Call Toll Free, 1-800-333-9041 with any questions and ask for Sherman, W2FLA. _______________________________________________ TowerTalk mailing list TowerTalk@contesting.com http://lists.contesting.com/mailman/listinfo/towertalk ```
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