[TowerTalk] Walking Down Crank-Up

[Grant Saviers]

It's nearly impossible as you ask since as the angle to the ground 
decreases, it is a full person reach upward with more than the tower 
weight as the force needed. It's a lever, so holding at 1/4 the length 
from the base and man height (5.4', 45 degree angle) the center of mass 
exerts more than the tower weight on the people who are then the pivot 
point.  At that angle of tilt and support point the force on the tower 
pivot bolts is upward.  I've seen a tower permanently bent when a well 
intentioned helper placed a support too near the pivot of a partially 
tilted tower.

Something to consider when a stepladder is used as a temporary support.  
It might be instantly temporary or bend the tower or both.  Also 
remember that rotator, mast, and antennas move the center of mass 
upward/outward significantly since they are effectively all concentrated 
loads beyond 22'.

A derrick or falling derrick is what you need.  A couple of sticks of 
Rohn 25 as a fixed derrick next to the pivot, with a strong back guy, 
some side guys, and a winch.  The guys MUST be low stretch, wire or low 
stretch rope, NOT nylon.

Grant KZ1W


On 10/13/2017 16:44 PM, Bob Matthews wrote:
> Hello All,
> I have a Hygain 52SS crank-up tower on a hinged base. Has anyone on here tried to walk a tower down this size? It's 22 feet nested. Weighs about 400 lbs I believe. Wondering how many men it would take to walk it down on it's hinged base from the vertical to the horizontal position on the ground. I don't believe there's enough room to get a crane in to do this, so I'm wondering how many people it would take to walk it down.
> Thanks in advance for your input.
> Bob  KT3RR
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