Tip: Heavy wing explained

Throught the testing phase of rv8a N33nc we incurred a heavy left wing and i read as much as i could in the forums. We checked trailing edge alignment of ailerons & flaps all to no real solution until one day i looked @ the trailing edge profile of both ailerons. They were not the same the left heavy wing was as it should be looked like a triangle with a projection of top and bottom skins formong a clean intersection of the top and bottom skins, the right starboard wing aileron trailing edge however did not have the same shape. The top and bottom skins intersected below the projected (rearward) bottom skin adding curveture to the wing hense more lift lighter wing. Solution I took a hand vice and took out the extra curve along about half the aileron trailing edge ( i made them look the same). Next flight no heavy left wing so by sqeesing the trailing edge it means get any additional curve out of the aileron.I hope this helps some of you out there. Cyril

I think squeezing the trailing edge is a Van's cure also. On the early models (-3's) this technique was used alot. Sometimes a little over squeezed.

Heavy RIGHT wing

OK, let me get this straight (no pun intended). My RV4 has a slightly heavy right wing, so I should squeeze the trailing edge of the left aileron-correct?

"sqeese " check profile

Hi check the profile of the light wing aileron if the top surface and the bottom surface do not form an isoselese triangle ie. bottom skin curved take out the curve. Curveture here adds to wing curveture more lift than the other wing.
I hope this helps. Remember you are not sqeesing you are altering shape to match other aileron.I hope this helps.

cyril

Read this....

http://vansaircraft.com/pdf/Wing_Heavy.pdf

side x side heavy wing RVs

Would it be valid to say that a perfectly square built side by side RV-6,7,9 will always have a left turning tendency when flown solo assuming pilot sitting in the left seat? Further assumptions would be equal fuel amounts and neutral aileron trim.

Steve

Steve said:

Would it be valid to say that a perfectly square built side by side RV-6,7,9 will always have a left turning tendency when flown solo assuming pilot sitting in the left seat? Further assumptions would be equal fuel amounts and neutral aileron trim.

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I measured and remeasured. But my 6A has a heavy right wing.

L.Adamson

Larry, have you tried adjusting the flaps? Make sure the flaps are retracting fully and not hanging up or rubbing. If that is all good try raising the left flap 1/2 turn on the drive mechanism and go fly. If that doesn't do it try lowering the right side 1/2 turn and go fly. Worked for me.

Geico266 said:

Larry, have you tried adjusting the flaps? Make sure the flaps are retracting fully and not hanging up or rubbing. If that is all good try raising the left flap 1/2 turn on the drive mechanism and go fly. If that doesn't do it try lowering the right side 1/2 turn and go fly. Worked for me.

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Both flaps seat against a fuselage fairing in flight. When you look across the wingtips, ailerons, and flaps; everything looks in alignment..............except my upward pointing aileron trim tab, which is one of the hinge types on the outboard aileron.

I'm going to do a bit of left aileron "squeezing" first, and see how that goes. The pressure on the stick is very light. BTW-- the new thread on prop replacement & now a heavy wing/right rudder is interesting.

L.Adamson

Rivethead said:

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Before doing any roll trim adjustments by squeezing aileron trailing edges, all builders should use a straight edge and do the check shown in Jim's post. First get both of the ailerons adjusted the same, then make adjustments as found to be need by flight testing.

In fact this should be a pre-first flight check for all RV's and should be done on the rudder and elevators as well. Elevators or a rudder that is not totally flat at the trailing edge can cause reduced effectiveness, undesirably light control forces, and even dynamic pitch an yaw stability issues.

rvbuilder2002 said:

...all builders should use a straight edge and do the check shown in Jim's post.

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Boy, I'd really like to know how Jim got his bends that perfect. I thought my ailerons were good, but they're not *that* good.

Ok Jim, what's the secret?

Dave

Today, I examined both of my 6A ailerons carefully, since I've had that right heavy wing. It took the full aileron trim, which is the old style servo in the aileron; and that wasn't quite enough to remain level.

The left aileron, did in fact, have a slightly larger trailing edge radius, than the right wing. I pulled my hand seamers (since I work with sheet metal by trade) out of the toolbox, and put some duct tape on them. For starters, I squeezed a sharper edge about half way across trailing edge of the aileron.

I then took it up for a 200 mile cross country. The hands off trim is now perfect! Now all I need to do, is install a permanent rudder trim. I've got a wedge, duct taped on..........since the "6" didn't have any built in vertical stab offset, like the newer models. I'm going with a small tab that goes past the trailing edge, since my plane is done in a WWII / invasion stripe paint scheme.

L.Adamson

Say, Larry.....

....if you'd rather not have a tab stuck on the rudder, put a -7 attach plate on the forward spar with the "joggle". Shouldn't take much time.....our -6 has one and no tab.

Regards,

pierre smith said:

....if you'd rather not have a tab stuck on the rudder, put a -7 attach plate on the forward spar with the "joggle". Shouldn't take much time.....our -6 has one and no tab.
Regards,

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It's crossed my mind, but I figure it might require a bit of fairing re-work too.

However, I really don't mind rudder tabs. When I hear a new plane is flying straight and true............is really isn't! The engine is offset and so is the tail; to battle the forces!

What I didn't want, is fixed aileron tabs in opposite directions on both wings. I've seen these on RV's as well as others. I'm glad the "squeezing" method is such a cinch!

L.Adamson

edit: PS..............has anyone conducted speed/drag testing; to determine if an offset vertical stab or trimmed/tab rudder ---- makes much difference?