On Tue, 22 Dec 1998 09:27:01 -0400 Jim Idelson <jimi@designet.com>
writes:
>
I am making plans for the top section, rotor, mast and thrust bearings
>in a new Rohn 25 installation. The mast will be about 18-20 feet long.
>The
>rotor will be mounted at the bottom of the top section. One thrust
>bearing will be mounted on the flat top. A second thrust bearing will
>be
>mounted on a plate 24 inches below the flat top. With this setup 10-12
>feet of the mast will extend over the top of the tower for mounting
>antennas.
>
One of the main benefits of using a second thrust bearing is to take
the SIDE LOAD off the ROTOR.
The most effective way to do this is to mount the *lower* thrust bearing
just above the rotor.
With the rotor removed, you will have 12 ft of mast / antennas above
the tower and only a 2 ft moment arm inside the rotor based on your
proposed plan. NOT a good idea.
The upside down mount on the lower bearing is an interesting idea,
ASSUMING the bolts / washers remain tight.
de Tom N4KG
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