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How to Balance Ailerons

Scotty G

Well Known Member
Hi gang,

My ailerons have a significant amount of paint on them after a recent paint job. I’ve looked in the drawings and build instructions I have (pilot, not the/a builder) and can’t find a procedure for balancing the ailerons. Can anyone point me in the right direction?

Thanks in advance.
 
Hi gang,

My ailerons have a significant amount of paint on them after a recent paint job. I’ve looked in the drawings and build instructions I have (pilot, not the/a builder) and can’t find a procedure for balancing the ailerons. Can anyone point me in the right direction?

Thanks in advance.

Never heard of balancing ailerons.
One possibility is to place weights positioned on top of the 3/4" steel pipe until your find out how much is needed. Then measure out that weight in small lead pellets and epoxy resin, mix and pour into the steel pipe (aileron removed and standing on edge with the other end of the pipe plugged).
Or melt the lead in a can with propane torch and pour.

Finn
 
Recommend you do not do anything other than the per-plans counter weight pipe.

Balance is about flutter, not about static gravity balance. Adding more weight could push you the wrong direction.

Carl
 
Hi gang,

My ailerons have a significant amount of paint on them after a recent paint job. I’ve looked in the drawings and build instructions I have (pilot, not the/a builder) and can’t find a procedure for balancing the ailerons. Can anyone point me in the right direction?

Thanks in advance.

What problem are you experiencing?
 
You dont say which rv model you have. This or electronic trim is the solution. Seach vans web store maual aileron trim, -vs- trying to balance.

https://store.vansaircraft.com/rv-7-7a-9-9a-manual-aileron-trim-kit-ail-t79.html

Uh, no.

I posted in the RV-8 forum, so I have an RV-8.

The problem isn’t trim; I have aileron trim and it functions fine. The change occurred when the paint job happened.

The shop put on an insane amount of material on the ailerons, and it’s changed their balance. (According to forum rules, I can’t name the shop publicly, but I’m happy to warn anyone away from the privately. It’s a Arizona shop, not in Eloy.)

The ailerons will ‘bounce’ between left and right in light turbulence and above. I damp it out after about three oscillations - but it wasn’t like that before. I have not tried it undamped by my hand.

It’s clear to me that the additional weight of the paint on the ailerons, aft of the hinge and no longer in check with the leading edge counterweight (if any), is out of whack.

So I’m looking to check what is going on and define the problem before I come up with any solutions.
 
...
So I’m looking to check what is going on and define the problem before I come up with any solutions.

Good call -- hand fly it and see what's what first. The oscillation you describe sounds more like the autopilot "hunting" (i.e. the roll gain is too high)...

B
 
Maybe I’m speaking Portuguese…

Although I do have an autopilot, I didn’t mention it yet because I don’t use it very much, and it may mask the problem.

The problem happens while hand flying in turbulence.

By saying I have not tried it “undamped by me,” I mean I have not had it occur without my hand on the stick.

I’d say there is a small range in the flush/wings level area that is a little dead zone. You get the ailerons moving in turbulence, and the ailerons break out “uncommanded” a little bit and cause a left-right-left wobble that I can damp out. But it’s like there is a force driving the ailerons out of flush, it excites a little, I damp it out, and I go on.

I have no way of measuring what the stick force is to damp and correct, but it’s super light and easy to do. Probably around a pound of force or less. Which tells me, if my ailerons are unbalanced, it’s not by much.

It’s almost like neutral static stability in the first breakout instant, then I can easily damp it. Kinda like power steering that’s way too sensitive.

It wasn’t this way before, and I believe it’s because there is more weight from paint on the ailerons aft of the hinge, and this now equals or outweighs any counterweight that may or may not be in the leading edge.

Hopefully that is more clear.
 
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Just me

If it was me, i would disconnect each aileron pushrod and see if it flops trailing edge down. If so i would use a scale and push up on the aileron and see how much force it takes to push it up.
If the trailing edge flops up, i would not worry too much.
Either way i would call Vans once you know how much it is “heavy”
 
Maybe I’m speaking Portuguese…

Nope; my coffee hadn't kicked in yet :)

Disconnect each aileron from the pushrod (at the aileron) and observe the action of the aileron; the aileron will want to drop the leading edge, in a hurry...

If this isn't the case, remove the paint and try again... I wouldn't recommend adding weight to the leading edge pipe.

On the matter of the deadband in the controls, clamp the trailing edge corner of the aileron to the wing tip and then attempt to move the stick left/right (DO NOT USE MUCH FORCE) and see how much slop there is. If ANY, I would start looking at rod ends (Heim bearings), Bell crank pivot bushing/bolt, etc. for any movement.
 
Trailing edge

Thought occurred to me: Did that additional paint change the shape of the trailing edge.

I guess to me the real solution would be to have the paint stripped and repaint, but I can understand reluctance to do so.

I see that Ralph beat me to it.

Finn
 
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The shop put on an insane amount of material on the ailerons, and it’s changed their balance.

Just my 2 cents, but I'll agree with Carl regarding trying to fix this issue with additional weight or ? ...

When anyone uses the phrase "insane" to describe a modification or behavior, it makes me a bit wary. I read this to mean you think it's excessive. That means it's not right. Proceed back to ground zero and make it right ... it's a flying object with your fanny strapped to it!

Just sayin'
 
Check rigging

I would check the aileron rigging before weighing and/or adding weights.
Proper rigging can solve many issues. Maybe rig both ailerons very slightly low on each side. Much easier than adding weight.
 
repaint?

I'm not trying to be a smart arse here, but if the problem is too much paint applied, would you consider getting them stripped and repainted? They're small enough that it could probably be done in a day ot two if removed from the aircraft. I'd do that before adding more weight.
 
I suggest you find someone very familiar with The RV and carefully inspect the installation/rigging. I think it unlikely the paint alone created your issue.
 
Mass Balancing Ailerons is more a factor of dynamic acceleration, or gust loading in flight. As it was explained to me, an updraft will cause an unbalanced aileron, with a CG behind the hinge line to "sag" increasing wing camber and augmenting the input by increasing lift.

That said, there is an ongoing arguments between the 100% balance camps and the less than 100% group.

NACA Technical Note 609 provides guidance.
 

Attachments

  • TN 609 Aileron Mass Balancing.pdf
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I am surprise or rather shocked by the number of folks who say not to do anything about it.

Balancing ailerons are important and if there is significant misbalance, then it is required. Years ago on my first build VANS recommended balancing them and even now they say if paint has caused much imbalance. It is also important to balance each separately.

Balancing them is not difficult, especially if one has pre planned for it. Unhook your aileron from push rod and place a small container/cup near where the existing weight is and add weight until your aileron look to be balanced. Then weigh the cup to see how much weight you need. Mine required about 5.5 and 6 oz each plane. Then you can just add that amount of weight next to the original lead weight.
On my planes, I pre-planned for this and added a couple of nut plates for this purpose but you can use a rivenut if you don't have a way of bolting it on.
 
I am surprise or rather shocked by the number of folks who say not to do anything about it.

Balancing ailerons are important and if there is significant ...

Sounds like you're talking about elevators, not ailerons? There is no place to add external weight on ailerons.

But, to the OP. I would check the trailing edge radius and straightness (a strait edge running chordwise should lay straight until it goes off the aft edge of the aileron. It shouldn't encounter a "speedbump" of metal at the TE). If that is OK, then I'd look at removing the paint and repainting with a non-insane amount of paint.
 
Sounds like you're talking about elevators, not ailerons? There is no place to add external weight on ailerons.

But, to the OP. I would check the trailing edge radius and straightness (a strait edge running chordwise should lay straight until it goes off the aft edge of the aileron. It shouldn't encounter a "speedbump" of metal at the TE). If that is OK, then I'd look at removing the paint and repainting with a non-insane amount of paint.
Oh yes, you are correct and I am sorry for the incorrect post here. I should have had my coffee first.
My comments are about the elevators.
 
I appreciate all the effort people made in the replies. Thank you.

I have a hard time believing the paint shop somehow crimped the trailing edges or otherwise deformed them.

The *only change* by my eye is the paint addition. I watched them spray the wing. It’s a hideous amount of paint. (I’ll be more than happy to warn you away from this shop privately.)

Rigging didn’t change.

At any rate, I’m suing the paint shop for breach of contract, and the owner became violent with me right off the bat - so simply getting the ailerons repainted there (or any correction work for that matter) is not an available avenue.
 
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