I was looking at my 40% wings today before I was going to cover and noticed something. The ailerons leading edge on my left wing is stick up above the wing about a centimeter. Will this make a big difference? If you dont know what I am talking about there is a picture attached.

So, does this mean that the aileron is twisted? Or are the hinges just that much higher? Either way, it could be fixed, with some time and effort. But it might be just fine the way it is, after its trimmed out. The plane will never roll exactly the same both ways I don't think, but chances are. It won't really be noticed.

a centimeter is damn near half an inch that would be significant for sure and cause a lot of trouble. You might be meaning a few millimeters. Usually this happens for two reasons, 1) the shaped leading edge of the aileron is larger than the trailing edge of the wing or 2) the hinge line is slightly off center and therefore the aileron sits higher above the wing than is should.

In either case the raised aileron will cause airflow dissruption over the surface and might in fact cause the plane to "roll" in the direction of the raised aileron, as if you were intentionally doing it. It would be acting as though the aileron has been deflected. You could remove the aileron and re drill the hinge holes and correct it if you felt so inclined or you could add sheeting over the surface of the wing to build it up then sand it smooth and blend it in to match the surface, the down side to this is one wing becomes heavier than the other which would mean greater attention to balancing.

Just take a heavy duty palm sander and grind it down until it's flush ! Sorry, I could'nt resist! I would remove/cut out the hinges and re-do it. Make sure you have a straight and centered hinge line, mark it and install some new hinges. On a 40% plane, we don't need no "steenkin" flutter![X(]

A belt sander with some 50 grit paper on it would save him more time

But seriously, it isn't covered yet, so I would just do exactly what Bass1 said and cut the hinges off back down to the wood and install new ones right next to the old ones only this time on the center line.

Yeah I was concerned about flutter. The other thing that concerns me is that the other side is right below about 2mm. And it is more likley off by a couple millimeters. I will recenter it today.

I wish that I could remember the article and magazine, but a ever so slight difference of the aileron leading edge actually helps against flutter. (dont ask me how!) I know that sounds wacked out.... now a centimeter or 1/4" or half inch seems way too much to me though! I would try to remedy that one. I will sight one example of a thicker aileron leading edge from my own experience! I had a great flying DP extra 330 that I added 1/32 sheeting too the ailerons top and bottom. This was added to help with the ridgidness since others complained of aileron flex on 330's. Anyway, after adding the sheeting, and recovering ect., there was a bit of a size difference from stock. It was of course 2/32 extra thickness which is not much, but was noticable when hinging. I just centered it all up and glued them in, feeling confident after reading that article that I may actually have helped the model in more than 1 way. I must say, that was the best flying model that I had owned. It flew beautifully even with a slightly (on purpose) thicker aileron leading edge. No flutter at all! So I guess what Im saying, a little extra thickness wont be a problem, if aileron is centered with equal amount top and bottom. If you have more than a little thickness though, I would have to agree with the above posts, its probably way too much! From your picture, if the bottom looks like the top centered, than I think its way too much!

No the bottom doesnt. The hinge line is off and I will center them and take abother pic today.

Going back to the statement about being a smidgeon thicker being better, that's correct.

The aft portion of a wing experiences a lot of turbulent air and airflow separation, so having a flight surface that's about a mm taller than the trailing edge of the wing where the moving surface joins it helps to keep the surface in "good" air, and keeps the flight surface more effective at higher angles of attack. Of course there's that point where the only airflow over the moving surface will be at the inboard section and is generated by the propeller only, but until that point and angle of attack is reached the thicker moving surface remains effective longer.

A centimeter is of course waaay too much.

I got it down to about 2mm each side. Will this be ok?

Absolutely fine. There is one other benefit I forgot to note. The slightly thicker moving surface reduces the propensity of the surface to "flutter", previously noted by "Flymyplane"..

Just wondering.. if the top of the aileron is high (slightly thicker) than the wing, the bottom of the aileron most likely will be (slightly thinner) than the wing. This is assuming the aileron was built to plan and is attached above the recommended centerline. If this is indeed the case, I believe you loose your "flutter reducing" benefit. Correct me if I'm wrong though

The picture was taken when the hinge line was off. Now it is corrected and as I said above both sides of the aileron are 2mm standout.

Sounds like your good to go! Is that what they mean when they say "enlarged control surfaces"?