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  #1  
Old 08-11-2018, 03:47 PM
togaflyer togaflyer is offline
 
Join Date: Apr 2013
Location: Cleveland Ga
Posts: 484
Default Aileron trim saga continues

So my left aileron defects downward. Based on previous postings and a document Van’s had on their website, I groved the outboard left aileron bracket to lower the aileron height. After multiple adjustments downward toward 1/4 inch, the deflection geometry has remained the same (the outboard aileron height was lowered but no change to the deflection). The outboard side of the aileron sits well below the slip stream. My next move is to restore the aileron to the original position before the bracket holes where groved, then add a trim wedge under the left aileron to see if it at least deflect th aileron upward.

I am I missing something, or is it is what it is and just go with the wedge if it works.
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  #2  
Old 08-11-2018, 04:50 PM
BobTurner BobTurner is offline
 
Join Date: Dec 2011
Location: Livermore, CA
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So, hands off, it is right wing heavy? I think you should be lowering the right aileron.

Last edited by BobTurner : 08-11-2018 at 04:51 PM. Reason: Spelling
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  #3  
Old 08-11-2018, 05:11 PM
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Mark H Mark H is offline
 
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Location: Indianapolis, IN, USA
Posts: 51
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I don’t think understanding the airflow around the aileron is intuitive, but you should lower the leading edge of the aileron on the heavy wing. I found this technique to be very effective.
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  #4  
Old 08-11-2018, 06:18 PM
togaflyer togaflyer is offline
 
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Location: Cleveland Ga
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Here is where I am confused. The right wing is heavy. Rigging double checked and good. On ground everything is aligned perfect. In flight, right aileron is in trail with wingtip. Left aileron trailing edge deflects downward maybe 1/2 inch. Does the airflow pressure come from the top or bottom of the wing. If it comes from the top, and it was a right wing issue, wouldn’t the right aileron deflect downward raising the right wing.
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  #5  
Old 08-11-2018, 06:58 PM
BobTurner BobTurner is offline
 
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Location: Livermore, CA
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Quote:
Originally Posted by togaflyer View Post
Here is where I am confused. The right wing is heavy. Rigging double checked and good. On ground everything is aligned perfect. In flight, right aileron is in trail with wingtip. Left aileron trailing edge deflects downward maybe 1/2 inch. Does the airflow pressure come from the top or bottom of the wing. If it comes from the top, and it was a right wing issue, wouldn’t the right aileron deflect downward raising the right wing.
During ground alignment, did you clamp the elevator neutral?
Align wingtips last. Are both flaps up against the aft spar? Do ailerons line up with flaps? Then and only then adjust wingtips.
Sight down the top of the wing. Does the aileron appear to smoothly blend to the top of the wing? If the leading aileron edge is vertically high (1/32” counts!) it will cause that wing to be heavy.
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  #6  
Old 08-11-2018, 07:21 PM
Mark H's Avatar
Mark H Mark H is offline
 
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Location: Indianapolis, IN, USA
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The left and right ailerons are connector, so in flight they find an equilibrium in trail. Looking at the deflection of the ailerons can be deceiving and isn't the real problem. Rigging of the ailerons doesn't have anything to do with a heavy wing. RV's are so sensitive that it only takes a little difference in the wings to cause a heavy wing.

Think of it this way, by lowering an aileron you are changing the angle of incidence very slightly on that wing. If your right wing is heavy, then you want to effectively increase the angle of incidence of the outboard right wing by lowering the aileron and thereby correcting the "twist" that's causing the heavy wing in the first place.
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  #7  
Old 08-12-2018, 08:17 AM
togaflyer togaflyer is offline
 
Join Date: Apr 2013
Location: Cleveland Ga
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Ok thanks. I will swap the brackets and lower the right outboard and see what happens.
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  #8  
Old 08-12-2018, 08:45 AM
Carl Froehlich's Avatar
Carl Froehlich Carl Froehlich is offline
 
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Location: Dogwood Airpark (VA42)
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Quote:
Originally Posted by togaflyer View Post
Here is where I am confused. The right wing is heavy. Rigging double checked and good. On ground everything is aligned perfect. In flight, right aileron is in trail with wingtip. Left aileron trailing edge deflects downward maybe 1/2 inch. Does the airflow pressure come from the top or bottom of the wing. If it comes from the top, and it was a right wing issue, wouldn’t the right aileron deflect downward raising the right wing.
Rigging is always frustrating. I warn builders it is not just “line up with the tooling hole and fly”.

I’ve posted on this before, so here is the summary:
- Verify the flaps are really all the way up on both sides. This is a fairly common problem.
- Clamp the elevator in neutral before doing any rigging adjustments. The control stick will pull/push the ailerons when deflecting the elevators - just the nature of the beast on the RV-10.
- With the flaps fully up, clamp one elevator trailing edge to the flap trailing edge. If the stick in not in the center, fix this first. Now adjust the other aileron to bring it in line with the trailing edge.
- With both ailerons aligned with the flap trailing edge (note flap, not wingtip) now measure the gap between the top of the aileron and the wing along the full length of the aileron. In most cases an aileron without a constant gap (or equal gap to the the other side) is the cause of a heavy wing. For this fix I get the “no hole” aileron bracket from Van’s to move it up/down/in/out.
- The very last step - fix any wingtip misalignment. It is very helpful to defer wingtip fit up until after the plane if rigged and rigging checked a few dozen times (I do this on the initial temporary wing install). The wingtip presents a large moment arm so make sure it is right.

Carl

Last edited by Carl Froehlich : 08-12-2018 at 09:36 AM.
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  #9  
Old 08-12-2018, 09:54 AM
JimS JimS is offline
 
Join Date: Sep 2012
Location: Mosinee,WI
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The thing that made a huge difference in my 6 that I haven't really seen mentioned is the ski jump on the rear wing skin to flap overlap. Bought the airplane, noticed the heavy wing condition, but trim was quite adequate to handle it. Finally decided to try work through the steps. Found flaps were not in alignment. Fixed that. Now the trim was about maxed out for wings !evel. When the plane was parked, left aileron was 2" up in the air compared to the wingtip. Also when moving the stick left to right, as one aileron passed even with the flap the other was not aligned. Fixed that. Finally checked the wing skin to aileron and flap overlap and found a ski jump on one flap. Had to remove the flap and carefully roll the flap leading edge a bit more. This had a profound effect on the trim. Trim lever back to neutral and heavy wing 80% gone. Might squeeze an aileron a bit but it is so close now I'll probably just leave it.
JimS
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  #10  
Old 09-23-2018, 05:06 PM
togaflyer togaflyer is offline
 
Join Date: Apr 2013
Location: Cleveland Ga
Posts: 484
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I finally have time to address my heavy wing issue again so I’m reaching out once more to get your input on my current status. I have the issues and things I did in bullet format:

My right wing continues to be heavy

I have required significant left aileron trim correction to offset the heavy right wing.

I rechecked and rerigged according to specs. Everything is right on, in a static condition.

In flight, the left aileron will lower approximately 1/4 inch based on the trailing edges of the wing tip and flap vs the left aileron. The right aileron looks about in trail.

I used a square 6 inches long, it will strike into the top of the outboard left aileron forward spar. Inboard side of left aileron and in and out areas of the right aileron spar clears.

I attached a plastic trim wedge under the outboard side of the left aileron. In flight it corrected the amount of aileron trim required to almost zero. The left aileron trailing edge is still slightly lower then the trailing edge of the wing tip, the right aileron looks like it holds just slightly above, but very minimal.

So with a slotted bracket, do I attempt to lower the outboard left aileron or ? On the aileron, Does the airflow load come from over the top of the wing or from the bottom pushing upward.

You continued input is appreciated.

Rich
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