[TowerTalk] Aluminum towers -- can you really "walk one up"?

[Bill N6MW]

Data: I had a 30' Universal Al tower weighing ~60#. Antenna + rotor was 
~55#. One none too young guy could walk the bare tower alone up easily. 
Not true once the weight was on top. However, 2 pretty strong guys + the 
older guy (probably also without the older guy) could walk that up 
without much trouble.

Alternate: For one older guy alone the not so well know and not so 
famous Non-Falling Derrick method was invented to raise and lower the 
whole thing with relative ease. This avoids the worrisome falling 
derrick feature that requires you to attach the tower to a vehicle and 
then drive that vehicle ever so carefully (on a dusty soil hillside in 
my case). (http://n6mw.ehpes.com/TowerRaising.pdf)


Calculated Data (which are not data at all, of course): The calculation 
of the force needed to walk up a tower may not be as quite as simple as 
it immediately sounds. It is pretty easy to find the 
perpendicular-to-tower force needed to provide the moment needed to tilt 
the tower up given the lever arm where you are lifting (which changes 
with angle). However, once the tower is tilted up substantially,a force 
perpendicular to the tower is no longer a matter of just lifting up. The 
pure upward force needed then goes up like the perp force/cosine(angle) 
unless you can tilt your body to that angle, which you can't at any 
significant angle. For example with the numbers from above example, 
ignoring tower taper to be conservative, at 45 degrees (worst case for 
that perp force), and for 6' walkers, the perp force needed is 212# but 
that requires you to lift 301# if you just lift up (~ 2 strong guys?). 
Furthermore, for angles above 45 degrees the required up force steadily 
increases. However, once you get closer to finished you can just supply 
a more nearly horizontal pushing force to get the job done. For example 
at 75 degrees, a horizontal force of 110# will get you the needed 106# 
perp force since you are nearly at perp here. Just how much horizontal 
force a person can manage, and without having their feet slip, will come 
into play.