[TowerTalk] Mosley PRO 57 B40 HD on Versatower M60

[Jim Lux]

At 02:27 PM 8/1/2006, Peter Voelpel wrote:
>My 100 foot mobile Versatower crankup MUST be guyed.
>I guess the additional downward force has been calculated for the size of
>wires and pulleys
>
>73
>Peter


http://www.fli.co.uk/Versatower/

The opening photo shows guys (slack on the upper sections before extension)..
One assumes that they've designed it appropriately.

Some years back, I was starting on designing an extremely lightweight 
telescoping tower that was guyed at any extension, but the "automatically 
adjusting" guys got very complex. It can be done, though. The challenge is 
because the angle of the guy changes as it extends, so you can't just use 
some sort of ratioed feed (where you feed out 1.4 ft of guy for every foot 
of extension, as you could do if it were fixed at 45 degrees).

We eventually went with a totally different strategy (renting a 200 ft 
construction crane)

Depending on the loads, one could use cleverly designed winches to both 
store the guys (in the retracted position) and anchor them (in extended 
positions).  What is an sailing ship but a bunch of guyed towers and spars 
that are all adjustable, under tension.. So the basic technology was worked 
out centuries ago.



>-----Original Message-----
>From: towertalk-bounces at contesting.com
>[mailto:towertalk-bounces at contesting.com] On Behalf Of Tom Osborne
>
>
>Maybe I'm mistaken, but I thought guying a crankup tower was a no-no.  Too
>much downward forces.  Did I seee that somewhere?  73
>Tom W7WHY
>
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