>but the farther away the attachment point is from the center of rotation
the bigger the angle on the guy wire so the higher the resistance to the
twist.
Here is some food for thought. Take it to the extreme where the torque arm
is lengthened and rigidly attached to both the tower and guy anchor point.
Twisting the tower will result in bending the torque arm.
Now, reduce the length of the torque arm to one inch less than the distance
from the tower and install a one inch guy wire. Please don't laugh. I know
hardware alone would not allow such a condition, but this is just for
visualization of force. In this case the tower could twist a fraction
without bending the arm. Or could it? Keep moving in to longer wire,
shorter arm. In each case the resistance to twisting is placed on
rigidity/strength of the torque arm and tension/strength of the guy wire.
IMO, if you compare the above to a six point torque arm system, well, there
really is no comparison.
Keith
-----Original Message-----
From: towertalk-bounces@contesting.com
[mailto:towertalk-bounces@contesting.com] On Behalf Of David Robbins K1TTT
Sent: Tuesday, August 03, 2004 2:51 PM
To: kr7x@comcast.net; 'Tower (K8RI)'; TowerTalk@contesting.com
Subject: RE: [TowerTalk] Rohn Torque Bar confusion
> When you translate the plane triangle section in rotation in its
plane,
> twist or torque load, initally the guys cannot resist the lateral
> displacement as the guy's line of action is perpendicular to theaction
> direction of the load. As the triangular section twists additionally
then
> there is created an angle between the line of force and the guy line
of
> action which can develop a vector resistance to the movement of the
> triangular section. This value of resistance is a function of the sine
of
> the angle created. It wil start at 0 degrees at rest, sine of 0
degrees
> is 0.
>
> This explains why the torsional resistance of the standard guying
scheme
> is so low and why if significant torsional forces are present in a
tower
> they twist.
>
> In this case the farther away from the center the guy attachment point
is
> really doesn't help with the torsional strength the angle between the
guy
> and the line of force of the torque is what matters.
>
but the farther away the attachment point is from the center of rotation the
bigger the angle on the guy wire so the higher the resistance to the twist.
Granted at 0 there is no force so it won't help with very small movements
but adding rigidly clamped arms that approximately double the radius of
rotation should increase the resistance proportionally. Also increasing the
radius to where the reaction force is applied increases the length of the
arm applying the force also increasing the reaction torque applied by the
guy wires.
David Robbins K1TTT
e-mail: mailto:k1ttt@arrl.net
web: http://www.k1ttt.net
AR-Cluster node: 145.69MHz or telnet://dxc.k1ttt.net
_______________________________________________
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
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