The 2 UST crankups I have are not tapered and the looseness between
sections is needed so they don't jam up, particularly when you try to
lower it and a side wind is present. My 472 does not have a winch and
power pulldown. I use a floor block and my tractor to lift and lower it.
The last thing you want is a tight fitting crankup tower.
The sections are supported by the cables. My 131 ft UST has 3 cables
at each section. This gives triple redundency and centers the tower
lifting. My TX472 uses single lift cables between sections and there is
a slight tendency for the sections to tilt a tiny bit during lift since
the cables are pulling on only one side of the section. It was used when
I got it and once it stuck on the way down since the section weight is
what makes it come down. When I finally got it down, I did a little
hammer work on the guide angles to loosen the fit. I also attached a
cable to the bottom of the top section which hangs down the center in
case it sticks. It has not happened in the last 10 years. Both towers
use a single lift cable on the bottom section with multiple passes, back
and forth, for mechanical advantage.
I use a 2 section ladder against the bottom secton to work on the
tower and antennas. I recently replaced the cables on the 472 and the
bearings in the pulleys by blocking the sections being worked on and
working from the ladder.
rpb wrote:
>
> I'll ask this again since I really didnt get much of response before, and it
> was buried in another lengthy post...
> Just bought a crank up, never thought i would but couldnt pass the deal up...
>
> Im not sure how to posit this question... On any of these crank-ups I
> realize one can stop it anywhere in between fully extended and retracted, but
> does the tower "lock-up" tighter when fully extended vs. wobble when ony
> partially so ? Or is the mechanical "fit" the same at all points on the way
> up?
>
> I realize that the entire load is held by the wire rope in any case, but what
> about the "mechanical lockup" for lack of a better term.... does the tower
> "lock up" better when at its full extension any better worse than at some
> other partial setting ? Is the "fit" of the sections tapered or identical at
> all settings? Im trying to describe the lateral inter-section mechanical
> "fit"....
>
> is the inter-section "wobble" a constant, or does it tighten up at full
> extension?
>
> tough to describe what i am thinking..... all the same query, different
> words....
>
> what if i put my head inside one of the lower sections while cranking it up
> to check the bottom of the rotor plate out ?
>
> -bob
>
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