On Tue, 15 Sep 1998 12:30:15 -0400, "Jim White, K4OJ" <k4oj@ij.net>
wrote:
>
>K9OFG asks:
>
>"So, how about locating the open side of the rotor bell such that the
>set-bolt is opposite, and loosening the u-bolts a bit at a time while
>tightening the set bolt till the set bolt has the mast clamped solidly?
>Seems that would avoid any centering problem"
>
>
>
>.......close, but no cigar, as they say here in Tampa........
>
>
>
>Especially if you are using a Telex ham series rotor which has built into
>its design, the anticipation of a 2 1/16" (did I get that right, Barry)
>diameter mast. (As opposed to the rotors which use split brackets on the
>top like Create, etc.)
>
>ONLY if the mast is this diameter will the mast NOT rotate eccentrically
>around the center of the rotor housing....in other words...almost never do
>you exactly have this...especially if you use plumbing pipe (a definite no
>no) instead of 2" OD mast.
>
>Why? Since one side which is holding the mast is fixed (the bell housing)
>its position relative to the center rotational axis of the rotor is
>constant.....it is FIXED, the u-bolts only serve to pull the must up
>against it.......and in reality, it does NOT center the mast unless the
>mast is the 2 1/16 OD, ever!
>
>Unfortunately this was learned from the ole school of hard knocks
>/////REALITY//////
>
Would it not be possible to place shims behind a smaller pipe to force
the center of the pipe over the center of the rotator?
>Draw yourself a sketch as viewed from above, the housing bell always is in
>the same position relative to the axis of rotation....taking it to the
>extreme, if you were to put in shall we say a 1" OD pipe it would align way
>too far into the vee of the bell.....if you used a 3" pipe it would not go
>far enough into the vee.......either way the end result is a mast which
>rotates eccentrically.
>
>NOW, couple that with the bolt coming in FROM ONE SIDE ONLY on your pointy
>top (part your hair to the side, to make it less noticeable)
This comes across as a personal slur. Did you mean it that way?
>and at one
>point of the rotor's rotational cycle you are at the "low spot" where the
>mast is the furthest in one direction off center...lets call it
>North....you then tighten your pointy top bolt.
>
>When the rotor turns 180 degrees to the South, the mast will still continue
>to be rotating eccentrically and now it is eccentric favoring the "high
>spot" - and your pointy top bolt is causing all kinds of havoc at rotor
>level because the mast is being forced sideways by the bolt, putting
>leverage on the rotor bell......
>
>Not a pretty sight......
>
>QSL?
>
>
>73,
>
>Jim, K4OJ
>k4oj@ij.net
>
Guy L. Olinger
k2av@qsl.net
Apex, NC, USA
--
FAQ on WWW: http://www.contesting.com/towertalkfaq.html
Submissions: towertalk@contesting.com
Administrative requests: towertalk-REQUEST@contesting.com
Problems: owner-towertalk@contesting.com
Search: http://www.contesting.com/km9p/search.htm
|