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## Re: [TowerTalk] Rohn Torque Bar confusion

 To: , "Tom Rauch" ,"TowerTalk" Re: [TowerTalk] Rohn Torque Bar confusion "Michael Tope" Wed, 4 Aug 2004 00:15:28 -0700
 ```Offhand I don't know the value of the modulus for a typical EHS guy wire, but just imagine for a minute how hard you would have to pull on a guy wire that is already tensioned to 600 lbs in order to get it to yield an additional 0.13 inches. Also consider that the difference between .008% and .006% is 33%, or in other words adding the 12" torque arms to the Rohn 55 increased the resistance to torsional rotation by a factor of 1/3. That's nothing to sneeze at. 73 de Mike, W4EF............................... ----- Original Message ----- From: To: "Tom Rauch" ; "TowerTalk" Sent: Tuesday, August 03, 2004 8:25 PM Subject: Re: [TowerTalk] Rohn Torque Bar confusion > I just did some guy wire length calculations. I used a 100' Rohn 55 tower > with a 12" torque arm at the top and a 80' guy radius. The guy wire length > is 126- 6.28". I then rotated the tower 10 degrees and the guy wire length > increased to 126' - 6.41" or 0.008% longer. If I connect the guy to the > tower leg, I get an increase length of 0.006%. Since in real life the > actual guy wire would not be longer this extra length would have to come > from slack in the guy or stretch. I am not a PE, but it would seem that the > is not enough different to provide much torque resistance with this system. > > > ----- Original Message ----- > From: "Tom Rauch" > To: ; "TowerTalk" > Sent: Wednesday, August 04, 2004 01:09 > Subject: Re: [TowerTalk] Rohn Torque Bar confusion > > > 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 > > > > _______________________________________________ > > 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 > _______________________________________________ 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 ```
 Current Thread Re: [TowerTalk] Rohn Torque Bar confusion, (continued) Re: [TowerTalk] Rohn Torque Bar confusion, Chris Pedder RE: [TowerTalk] Rohn Torque Bar confusion, David Robbins K1TTT Re: [TowerTalk] Rohn Torque Bar confusion, Don Havlicek RE: [TowerTalk] Rohn Torque Bar confusion, Keith Dutson RE: [TowerTalk] Rohn Torque Bar confusion, David Robbins K1TTT Re: [TowerTalk] Rohn Torque Bar confusion, Tom Rauch RE: [TowerTalk] Rohn Torque Bar confusion, Keith Dutson Re: [TowerTalk] Rohn Torque Bar confusion, kk9a Re: [TowerTalk] Rohn Torque Bar confusion, k1ttt Re: [TowerTalk] Rohn Torque Bar confusion, Tom Rauch Re: [TowerTalk] Rohn Torque Bar confusion, Michael Tope <= YagiStress Web Site was Re: [TowerTalk] Rohn Torque Bar confusion, Pete Smith Re: [TowerTalk] Rohn Torque Bar confusion, Tom Rauch Re: [TowerTalk] Rohn Torque Bar confusion, Tom Rauch Re: [TowerTalk] Rohn Torque Bar confusion, kk9a Re: [TowerTalk] Rohn Torque Bar confusion, kr7x Re: [TowerTalk] Rohn Torque Bar confusion, kr7x Re: [TowerTalk] Rohn Torque Bar confusion, Dave Hachadorian Re: [TowerTalk] Rohn Torque Bar confusion, kb9cry Re: [TowerTalk] Rohn Torque Bar confusion, Tower (K8RI) RE: [TowerTalk] Rohn Torque Bar confusion, Keith Dutson