[TowerTalk] Recommendation for mast on bottom mount

[Jan Erik Holm]

However can also been done a lot simpler forexample with
a "Hardy disc".

/SM2EKM
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Jim Jarvis wrote:
> W3GM used bottom mount rotors on all of his 100' 25g towers.
> 
> The actual mast and the 'torque tube' were of different material.
> 
> He used thin-wall irrigation tubing, 100' of which weighed maybe
> 20 lbs.  No idea what % of that was carried by the rotor, and what %
> might have been hanging from the thrust bearing.  The load was
> light, in any case.
> 
> The effect of this was to allow the arrays.. 3 el fullsized 40, for
> example...
> to rotate in the wind somewhat, taking peak loads off the rotor. I think he
> turned the 40m array either with a tailtwister or a ham-4.  In the time
> I operated from there, maybe 4 seasons, I never remember a major rotor
> problem.
> 
> n2ea
>