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  #11  
Old 01-01-2017, 08:37 AM
Mudfly Mudfly is offline
 
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Location: Alpharetta, Ga
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I just went through this step on my 14A project. I am by no means an expert with this, and looks like you have some much more experienced advice, but is 1/8" offset between the two counterbalance arms something that needs to be fixed? If you split the difference, thats 1/16'' offset between the two counterbalance arms (unclamped from "trail" position). One counterbalance would be up 1/16" and the other down 1/16" when rigged with elevator pushrod later on...,or checked with wood block between horns and bolted together and checked now.
Like someone else posted, how does the symmetry of the rest of the L/R elevators look when using the 1/16" offset. Not only trailing edge, but the whole surfaces of the two elevators. Tough to get exact here, but look at them visually and use levels, straight edge, or laser as appropriate to get an idea of what they look like.
The reason I mention this is because when I clamped my counterbalance arms in the trail position, I discovered what appeared (visually, straight edge, laser, etc.) to be an offset between the two elevator surfaces/trailing edges. I ended up, after much consideration, purposely offsetting the counterbalance arms to get better symmetry between the two elevators over all. I then drilled the elevator pushrod bolt hole in the horns. It now "appears" that my overall elevator symmetry is much better and the offset at the counterbalance arms is barely noticeable.
My "fix" appears to be in the minority with the other advice you are getting, but thought I'd put it out for discussion.
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  #12  
Old 01-01-2017, 09:39 AM
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flion flion is offline
 
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Quote:
Originally Posted by Dbro172 View Post
How is the alignment of the trailing edges of the elevators? Before you go any further run a straight edge (or even eyeball) the trailing edges, then check the counterbalance arm alignment with the H stab while the elevators are aligned and in trail.
I had this problem with mine. Due to slight manufacturing differences, the trailing edges were even but the counterbalances were off slightly. I put the elevators on a shot bag under the spar and then used a rubber mallet to adjust the counterbalances. 1/8" would be too much, but 1/16" on each (being careful to adjust in the right direction) was just fine and left no distortion on the skins. Still not perfect, so I'll just leave the elevators in full up position on the ground so no one will be able to tell.
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  #13  
Old 01-02-2017, 12:12 PM
rvdave rvdave is offline
 
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That worked great to move/enlarge the hole, welded washer on the outside and brought the alignment back to where it should've been. Thanks for the suggestion .
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  #14  
Old 01-02-2017, 01:08 PM
rvbuilder2002 rvbuilder2002 is offline
 
Join Date: Jul 2005
Location: Hubbard Oregon
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Quote:
Originally Posted by Robert Anglin View Post
We simply took some tubing and cut it beveled. then installed it with a longer bolt. It is much the same as using the Camber-Caster shimming on a cars front end adjustment. You make a couple of them, put one on the inside and one on the outside, Put the bolt through, bring the bolt up to just loose and then turn the bevel to get the alinement you wish. Kind of adjustable if you will. Hope this helps. Yours as always. R.E.A. III #80888
Not what I would recommend unless a very thick wall tube was used.
With a thin wall tube, if it has less diam than the AN960 washers that we normally use for spacers it will have less stability/resistance against rocking against the face of the elevator horn.
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  #15  
Old 01-02-2017, 01:09 PM
rvbuilder2002 rvbuilder2002 is offline
 
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Quote:
Originally Posted by flion View Post
I had this problem with mine. Due to slight manufacturing differences, the trailing edges were even but the counterbalances were off slightly. I put the elevators on a shot bag under the spar and then used a rubber mallet to adjust the counterbalances. 1/8" would be too much, but 1/16" on each (being careful to adjust in the right direction) was just fine and left no distortion on the skins. Still not perfect, so I'll just leave the elevators in full up position on the ground so no one will be able to tell.


There are many places in RV construction that hitting with a hammer is appropriate.

This is not one of them.
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  #16  
Old 01-03-2017, 04:09 AM
paul330 paul330 is offline
 
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Surely there is no issue with the horns being slightly out of alignment due to manufacturing tolerances. Line up the elevator trailing edges and match drill. The stops will need to be adjusted and one side will hit the up stop and the other the down stop.

Or am I missing something.......?
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  #17  
Old 01-03-2017, 07:22 AM
vic syracuse vic syracuse is offline
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Quote:
Originally Posted by paul330 View Post
Surely there is no issue with the horns being slightly out of alignment due to manufacturing tolerances. Line up the elevator trailing edges and match drill. The stops will need to be adjusted and one side will hit the up stop and the other the down stop.

Or am I missing something.......?
You are dead on. It is not the alignment of the horns that is critical, but the alignment of the flying surfaces. Adjusting the stops is the right thing to do as well. I've seen it on many airplanes, including my own.

And, as Scott mentioned, the bolt with a spacer beveled on each end is not the way to go. The elevators need to be firmly attached to each other with no possible movement. I check them on every preflight.

Vic
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