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08-01-2017, 12:44 PM
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Join Date: Mar 2017
Location: Birmingham, Alabama
Posts: 1,643
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Elevator Horn and Rigging
We finished rigging the elevators and the manual says there will be some offset with the horns, ours are off about 1/4 inch.
Everything seemed to rig well and we get the minimum 25 degrees of negative deflection and at least 30 positive, but the left elevator has considerably more negative deflection (almost 5 degrees) than the right, guessing due to where I drilled the hole.
Any thoughts? Just leave and "build on"?
Assuming that the final rigging will not be full deflection .. haven't read that far ahead.
If I did want to get them more consistent I guess I would need to have someone weld the hole and re-drill, not sure how that's going to look.
__________________
RV-14A #140376
N196 (Flying)
2019 Bronze Lindy
Last edited by bkervaski : 08-01-2017 at 12:57 PM.
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08-01-2017, 01:00 PM
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Join Date: Jul 2005
Location: Hubbard Oregon
Posts: 9,035
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The deflection is dependent on the angle traveled when the horns hit the travel stops.
When two elevators are properly aligned with each other (and bolted together at the push rod connection point), they should move with the same amount of deflection angle when the horns hit the travel stops.
__________________
Opinions, information and comments are my own unless stated otherwise. They do not necessarily represent the direction/opinions of my employer.
Scott McDaniels
Van's Aircraft Engineering Prototype Shop Manager
Hubbard, Oregon
RV-6A (aka "Junkyard Special ")
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08-01-2017, 01:03 PM
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Join Date: Mar 2017
Location: Birmingham, Alabama
Posts: 1,643
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Quote:
The deflection is dependent on the angle traveled when the horns hit the travel stops.
When two elevators are properly aligned with each other (and bolted together at the push rod connection point), they should move with the same amount of deflection angle when the horns hit the travel stops.
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They do, the difference is just when observing independently, not bolted.
Edit: Clarification, the forward most offset horn hits, but the elevators deflect the same amount when bolted together.
__________________
RV-14A #140376
N196 (Flying)
2019 Bronze Lindy
Last edited by bkervaski : 08-01-2017 at 01:07 PM.
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08-01-2017, 01:21 PM
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Join Date: Apr 2015
Location: Ponte Vedra, FL
Posts: 1,474
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Quote:
Originally Posted by bkervaski
They do, the difference is just when observing independently, not bolted.
Edit: Clarification, the forward most offset horn hits, but the elevators deflect the same amount when bolted together.
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BEFORE drilling the horns - you can adjust the rod ends on the side with more deflection to make the deflection equal, assuming you have good clearance from the spar - I adjusted each of mine away from spar slowly until I had the right amount of travel. Now that you've drilled horns, and as long as both elevators as a unit have good travel, you should be good to go. Probably not worth welding/re-drilling to make them "perfect".
Last edited by mturnerb : 08-01-2017 at 01:24 PM.
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08-01-2017, 01:25 PM
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Join Date: Mar 2017
Location: Birmingham, Alabama
Posts: 1,643
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Quote:
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BEFORE drilling the horns
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Haha! My second RV is going to be perfect 
__________________
RV-14A #140376
N196 (Flying)
2019 Bronze Lindy
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08-01-2017, 03:34 PM
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Join Date: Jul 2005
Location: Hubbard Oregon
Posts: 9,035
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Quote:
Originally Posted by mturnerb
BEFORE drilling the horns - you can adjust the rod ends on the side with more deflection to make the deflection equal, assuming you have good clearance from the spar - I adjusted each of mine away from spar slowly until I had the right amount of travel. Now that you've drilled horns, and as long as both elevators as a unit have good travel, you should be good to go. Probably not worth welding/re-drilling to make them "perfect".
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Adjusting the rod end (elevator hinge points) lengths to vary the amount of deflection relative to the elevator stops is not recommended.
__________________
Opinions, information and comments are my own unless stated otherwise. They do not necessarily represent the direction/opinions of my employer.
Scott McDaniels
Van's Aircraft Engineering Prototype Shop Manager
Hubbard, Oregon
RV-6A (aka "Junkyard Special ")
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08-01-2017, 04:33 PM
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Join Date: Apr 2015
Location: Ponte Vedra, FL
Posts: 1,474
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Quote:
Originally Posted by rvbuilder2002
Adjusting the rod end (elevator hinge points) lengths to vary the amount of deflection relative to the elevator stops is not recommended.
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Understood - I was actually describing adjustments to get full deflection without binding. My bad in not making that clear. Also:
1. It's REALLY hard to get the center of the rod end exactly 13/16" away from the spar since you are measuring to the middle of a hole AND there is 180 degrees of travel between options.
2. If one of the two for each elevator is off a bit, the elevator is more prone to bind
3. On first try one of my elevators bound enough that I had to let each rod end on that side out a tiny bit (like 1/2 turn on one side, 1 on the other). 13/16" still fell within a small range of error given the difficulty of measuring.
4. What other option does a builder have if there is binding, assuming adjustments to the rolled leading edge have been made to a reasonable extent?
5. I was describing the adjustments made to relieve binding, not in relation to the stops (range was adequate if taken to stops, binding was the problem)
6. After adjustments, distance from torque tube to spar was within specs as described on plans page 11-03.
Finally - I walked through everything I did with a DAR/A&P/EAA Tech Counselor who has built multiple Vans aircraft and he saw nothing wrong with this approach.
I should have been more clear in my description.
Last edited by mturnerb : 08-01-2017 at 05:04 PM.
Reason: Tone of my response
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08-01-2017, 04:46 PM
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Join Date: Mar 2017
Location: Birmingham, Alabama
Posts: 1,643
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This is what mine looks like .. considering plug welding and re-drilling to get it to align better, even though I'm getting 25 degrees.

__________________
RV-14A #140376
N196 (Flying)
2019 Bronze Lindy
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08-01-2017, 04:48 PM
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Join Date: Apr 2015
Location: Ponte Vedra, FL
Posts: 1,474
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Quote:
Originally Posted by RV8JD
Hmmm ... I read Scott's reply and did not think it was judgmental or critical. It seemed like just a statement.
BTW, I think Scott is pretty helpful here. Sometimes his reponses are short, but that may be because he replies to a lot of posts, and I assume he has a life away from RV's and this Forum. 
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I stand corrected, but terse statements sometimes lead to confusion and - in their very brevity - can convey a dogmatic rather than instructive tone. FYI not only do I agree with you regarding Scott's being helpful - I said virtually the same thing in post #36 of this thread: http://www.vansairforce.com/communit...76#post1190276
I edited my post in fairness to Scott - the last thing I'd want is for him to be inhibited from contributing to this forum!
Last edited by mturnerb : 08-01-2017 at 04:50 PM.
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08-01-2017, 04:53 PM
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Join Date: Apr 2015
Location: Ponte Vedra, FL
Posts: 1,474
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Quote:
Originally Posted by bkervaski
This is what mine looks like .. considering plug welding and re-drilling to get it to align better, even though I'm getting 25 degrees.

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I'd run it by someone with more experience than me (i.e. DAR/EAA tech counselor, Van's) BUT I think you're well within the range of normal deviation of horn position and if you have good range of movement, why fix what's not broken?
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