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Aileron trim saga continues

togaflyer

Well Known Member
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.
 
So, hands off, it is right wing heavy? I think you should be lowering the right aileron.
 
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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.
 
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.
 
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.
 
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.
 
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
 
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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
 
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
 
SNIP

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 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.

Rich

Rich,

I offer if in level flight one aileron in trail and the other 1/4? down says rigging is not right. Add to that, the left aileron down would imply your left wing is heavy, not the right.

Look beyond stuff in line - this means little as you have not determined what ?in trail? is for the ailerons. Take another look at my earlier post.

One other point, as previously mentioned always make sure you have the elevators clamped in neutral before you do any aileron rigging adjustments. The control input on the RV-10 is asymmetric - tending to pull they aileron push tubes when deflecting the elevators.

Carl
 
My wing tips were way off on my -10 as they came from the factory and required that I split the trailing edge the full length to get them straight. Just a thought, but had I not done that I am sure I would have had issues trying to get the rigging right.
 
I double checked the rigging and it’s rght on. I clipped the right aileron in trail and deflected the left aileron down. There is enough play that, aerodynamically, airflow could be impacting it. As the great philosopher Forest Gump said “I’m not a smart man” and for me when it comes to understanding airflow, yep it describes me perfectly. I got some good info on what to check on the airfoils, so I will do that and see.
 
I've found the wintips aren't a good reference to use for aileron alignment. Use the flaps. Can you post pics of the flap to aileron alignment in flight?

Are you extra certain the flaps are both equally and fully up?

What's your weight on each of the main wheels? Have you run the heavy wing tank low to see how much weight it takes to get it "not heavy"? Not sure why yet, we have 30lbs on the left wheel which I think is the main cause of our heavy left wing. When we burn 10g off the left tank it's much better. Also, our right flap is slightly lower than the left in reference to the fuselage when fully retracted. Next time our wing roots are off, i'm starting at the flap.
 
I've found the wintips aren't a good reference to use for aileron alignment. Use the flaps. .
No they are not. But if they don't line up straight with the ailerons when the ailerons and flaps are in alignment, they will act as a big trim tab.
 
I double checked the rigging and it?s rght on. I clipped the right aileron in trail and deflected the left aileron down. There is enough play that, aerodynamically, airflow could be impacting it. As the great philosopher Forest Gump said ?I?m not a smart man? and for me when it comes to understanding airflow, yep it describes me perfectly. I got some good info on what to check on the airfoils, so I will do that and see.

Based on your rigging and flying information, it sounds like you have some play in the ailerons that needs to be corrected. There should be zero play between the left and right movement.
 
Changing the aileron rigging will not cure a heavy wing! The ailerons will always trail where the forces are equal. If one trails low and the other high; that means they are in equilibrium. The problem is in the wing's incidence. If the wing was built with a different twist than it's mate; it will have a different average incidence than the wing on the other side.

Low or heavy wing cure is to slot the aileron hinge brackets and move the whole aileron down on the heavy wing: it's a bandaid patch but it works!
 
Aileron hinge position

So, the aileron hinge issue can in fact cause what you have. Stand in front of the plane and get the ailerons in neutral, look along the bottom surface of the wing skin and see if you have an aileron(focus on the aileron leading edge, not trailing edge) that is lower/higher on the outboard side than the inboard side..in other words, one hinge is drilled lower/higher than the other. The fix is to slot the hinge U channel bracket or drill up a new one. I had this scenario on my -4, which I built,and it took a while to figure it out.
 
What Bill said.

While slotting of the aileron bracket will address a low or high aileron (common problem), it does not fix the ailieron that is not parallel to the wing - or not the same spacing as the other aileron. Here the solution is to order the ?no hole? aileron bracket(s) from Van?s and drill the mounting hole off center as needed to fix the problem.

The other most common problems are:
- Rigging the plane with one or both flaps not all the way up.
- Fitting the wingtips before final rigging - and ending up wingtips out of line.

Carl
 
heavy wing issue

Hi all, need advice to solve this.
I started to fly my -10 that was built by other builder and I finished.
The issue is that she flies with the right wing down tendency and in order to maintain the track I need to step the right pedal a little.
When I run with the autopilot , the right wing stays down about 3 degrees and she flies uncoordinated ( the ball is out of the center to the right side)
What should I do first ?
Your imputs will be highly appreciated.

Jorge Ezquerra
Buenos Aires
 
Hi all, need advice to solve this.
I started to fly my -10 that was built by other builder and I finished.
The issue is that she flies with the right wing down tendency and in order to maintain the track I need to step the right pedal a little.
When I run with the autopilot , the right wing stays down about 3 degrees and she flies uncoordinated ( the ball is out of the center to the right side)
What should I do first ?
Your imputs will be highly appreciated.

Jorge Ezquerra
Buenos Aires

The short answer is to start the rigging process from the beginning. From what you have said, it is impossible to tell you what it wrong - so just start over.

For a ball way out like yours, I would also jack up both wings so the gear is off the ground and see how the wheel pants are mounted. Bad wheel pant and/or gear leg fairing rigging can put the ball way out.

Do all this before you add stuff like a rudder trim tab.

Look at my previous posts on rigging as a placer to start.
Carl
 
If the nose wheel sticks in a left or right pivot that will cause a non-centered ball condition. I?d check to make sure nose wheel breakout torque isn?t over spec.

Cleveland makes an easy to install rudder trim wedge, $18.50.
 
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