I have used a rotor plate for a Tristao Tower for 33 years. The plate sits
on the cross bars and has a plate on all three sides below the cross bar. I
helped with a US Tower Installation and it seems they still use the same
concept.
The problem I have had is that even with several stacked beams, a T2X rotor,
and a W9IIX ladder mast (200 lbs by itself) that strong winds will pick up
all the beam/mast weight and place them
out of position. This has happened twice. I used a long crow bar to lift
the plate up and put it back in place. I finally put a Rohn guy bar
mechanism around the plate (gives an extra 1" of protection to lifting and
turning). This has held for 7 years. The guy bar also hold the plate very
tightly.
I think the reasoning behind this type of plate is that attaching the plate
to side tubes (as with Rohn 25/45) would not let the tower be freely cranked
up and down. To do so you would have to removes the clamps.
Dave K4JRB
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