In a message dated 98-11-23 07:46:52 EST, W4EF@pacbell.net writes:
> My concern would be with the side load on the rotator.
> If you are using a point top with no thrust bearing, and the
> rotator only a couple of feet below the gib sleeve, my guess
> is that you will be subjecting the rotator to a pretty nasty
> side load. Imagine a 12' lever arm working against 2' lever with
> the gib sleeve as the fulcrum - this is a 6:1 force multiplier.
> I am planning on using a flat top with a TB3 and a second
> bearing 6' or 8' below the top. The rotator will probably be 10'
> below the top bearing. This should ensure that the all the side
> load gets taken up by the bearings instead of the rotator.
>
The rotator will be okay. For one thing, the tapered top tube will
constrain the side forces almost entirely. In other words, the tube will only
allow the mast to move a little distance. Secondly, the T2X for instance will
take 3,000 ft.lbs. of lateral force on the top of the rotator before breaking
so there's not much danger of a problem with it either.
> I'll let you know when I get my spreadsheet done. It will be
> interesting to plug in your numbers once I get this thing checked
> for errors (I will probably need a legal disclaimer too - I am not
> a registered P.E. - strictly amateur hour here)
>
Let me know too - I'd like a copy of it.
Cheers, Steve K7LXC
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