[TowerTalk] Fwd: Guyed + self supporting /2 ??

[TexasRF--- via TowerTalk]

Hi Rick, I have used the falling derrick system on towers up to 60ft. I am  
not familiar with the tipping point phenomenon so you might elaborate on 
that a  bit.
 
73,
Gerald K5GW
 
 
 
 
In a message dated 10/18/2014 9:05:28 A.M. Pacific Daylight Time,  
richard at karlquist.com writes:

An  additional consideration in tilting up a
tower in one piece is how much  guying is needed.
While Rohn 25 can be tilted up, it typically
requires  multiple levels of guying just to be
tilted up.  This is without any  consideration
of wind.  This in turn rules out a simple gin
pole or  crane and requires a falling derrick, which
pulls on both the upper and  lower guys.  A
lighter weight tower with greater strength
such as  an aluminum self supporting type can
be tilted with a simple gin pole using  one
lift point.  Additional levels of guying for
wind purposes can  still be used after erection
is complete.  Falling derricks have their  place,
but are definitely more complicated, and are
harder to control  because of the tipping point
phenomenon.  You essentially need dueling  winches
to get through the tipping point.  If anyone
has solved  this problem, please let us know.

Rick  N6RK
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