Hi Casey and all,
>Martin says the tower does not have to be guyed but I'm
>not sure bolting it to the roof would hold the weight. I can't
>crossbrace the legs because I do not have access to the atic space.
If you believe that all you have to do is use some hefty wood screws to
secure the tower brackets to the plywood roof boards... boy are you going
to be in for a surprise when the wind blows the thing over. Forget the
vertical weight... it's the side forces you need to contend with. Please
be advised that I just lost a few beams when the large screw eyebolts that
held the guy lines pulled out of my roof turning my push up mast into a
pretzel. I didn't take my own advice and paid the price for it.
If you tell me that you'll be bolting through the plywood into the roof
cross members...(joists or rafters) that's a different thing entirely.
Trouble is it's very difficult or know for sure if in fact your screw did
go into the joist...or maybe just the edge of it. Sure, everything should
be on 16" centers... but, as the song says... "It ain't necessarily so!"
So, if you only could get into the attic to check... then go in with 2 x
4's or 2 x 6's and some nails and drill and do the job properly.
Otherwise, you're asking for trouble.
As for the expense.... well, when you see how the GM towers are made... it
behooves anyone with a 1/4" drill and a hack saw not to be able to make his
own... if only you could find a cheap source of aluminum angle stock. You
don't have to be a rocket scientist for this project. A nice thing to
consider is making the top large enough to hold a thrust bearing so that
you can put your rotor inside and near the bottom.
I use a 9-ft. South River Tripod Roof Mount (unguyed) and it lacks the
thrust bearing feature necessitating my putting the rotor above the roof
mount's top. I hold up a TA-33 and R-5 about 5-ft above that.
If expense is no object... by all means go for the GM tower...(It's a real
nice one as I saw at Dayton) but do what ever you can to gain access to
the attic first.... otherwise... forget it...IMHO
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