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Another heavy wing thread (RV9A)

dbaflyer

Well Known Member
I've had a heavy right wing since first flight and I did try to adjust the outboard right aileron by slotting the bracket but that did not seem to have any affect. In the mean time I just put a trim tab under the left aileron and have been flying for 2+ years that way.

Fast forward and I'm looking to take another look at getting this resolved before getting the plane painted. I flew yesterday with full left tank and no passenger. Took off with 14 gallons in the right tank and flew until there was 4 left according to the g3x. The heavy wing was still there but now the aileron trim was able to trim it out. Coming into landing (slower speed) the left wing became the heavy wing. I filled the right tank upon landing and added 14.5 gallons

What I see during flying straight and level is the right aileron is slightly above the right flap. When I release the stick the right aileron wants to raise about 1/4 inch or so. My flaps are up tight against the fuselage and sighting down the wing they seem to be positioned Ok. The flaps are also straight and in-line with the aileron when sighting down the trailing edge when doing this individually (left and right side checked separately).

I've seen van's recommended procedure and read every post I could find here. Sometimes it is hard to decipher myth from reality. Looking for someone near KCID who knows the overall process and has been through this before who is willing to help provide some expertise and work through the process.
 
I have done this for a couple of folks in my area in addition to my own. you are only an hour flight and I may be able to drop by on my next trip to Ames in 3-4 weeks. Ifly right over CID. Ironically, I bought my 10 QB kit from a guy in cedar rapids.

On the last one I did, the P/O couldn't figure it out, so dropped one of the flaps almost an inch from in trail to address it. Once we had it all fixed up and flying hands off, he gained almost 7 knots in cruise.

PM me if interested

Larry
 
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I also had a heavy wing. I tried all of the slotting of the brackets which had zero effects. I ended up just using a small wedge under the right aileron. I started with a 6 inch wedge and eventually took off an inch. It flies nice and straight now. Here are photos of the ailerons in flight. You can see how the right side needs to be slightly up and the left side is slightly down about 1/8".

IMG_5731-M.jpg


IMG_5732-M.jpg


Everything is rigged correctly. Sticks are both centered, aligned with the trailing edges of the flaps and the alignment tooling holes. The wedge is just a plastic piece I got from some supplier here (Avery? Not sure who might have this available now). It is held on with 3m VHB tape.
 
SNIP..

Everything is rigged correctly. Sticks are both centered, aligned with the trailing edges of the flaps and the alignment tooling holes. …SNIP

I recommend you do not consider rigging with tooling holes as the gold standard. Depending on other issues, you could get the tooling holes to line up and be way off on rigging. Remember the tooling holes assume:
- The ailerons are hung at the correct height relative to the wing skin, and that height is the same across the length of the aileron
- The ailerons do not have a twist
- The ailerons are parallel to the wing trailing edge
- The flaps do not have a twist

Side note - on almost every RV I helped rig, the flaps where not at the same height when fully retracted. Here use straight edges across the wing skin to measure height of the flap trailing edges - fix any variance between the left and right flap as the very first step in the rigging process.

Carl
 
Larry is going to stop over in a couple weeks to help measure the aileron heights and see what might be going on.

Bruce your aileron positions are pretty much exactly where mine are in level flight. When I let go of the stick the right wants to rise even further and the left wants to go lower.
 
HOW TO DIAGNOSE AND FIX A HEAVY WING

Look up this information on Vans website. Just do a search. Might be helpful.
Cheers
 
Heavy wing

When I purchased my RV6 it had a significantly heavy left wing. I read all the suggestions on the forum and on Vans website. I checked the wings the ailerons and hinges. I was certain the light aileron trailing edge squeeze would not fix such a significant roll but I was wrong. I followed the suggestion from Paul Dye many years ago about using angle strips and a series of clamps to squeeze the trailing edge. I was very sceptical but it actually worked perfectly and I can now fly hands off with the aileron trim in the middle. The surprising thing is you cannot even see the adjustment you have made. Don’t discard it as a solution.
 
When I purchased my RV6 it had a significantly heavy left wing. I read all the suggestions on the forum and on Vans website. I checked the wings the ailerons and hinges. I was certain the light aileron trailing edge squeeze would not fix such a significant roll but I was wrong. I followed the suggestion from Paul Dye many years ago about using angle strips and a series of clamps to squeeze the trailing edge. I was very sceptical but it actually worked perfectly and I can now fly hands off with the aileron trim in the middle. The surprising thing is you cannot even see the adjustment you have made. Don’t discard it as a solution.

Squeezing the trailing edge of the light wing is in the instructions, but seems to be considered the last resort. I have a light right wing (or heavy left wing) and I'm probably going to squeeze the aileron as I can't see anything else that might be causing it - however a small misalignment can have a huge impact on balance at 180kts.

My QB ailerons are kind of "fat" at the trailing edge, so I have a lot to work with. I want to set up some very consistent tests so that I know when I've "fixed" it, and have not yet taken the time to do that. Perhaps I just need to squeeze a very small bit, fly, and see how it feels. Probably overthinking it.

My aircraft also likes a bit of left rudder at speed to keep the ball centered - no idea if this is related.
 
Just me

On my 9a, the trailing edge of the flaps and ailerons are not folded over, so squeezing the trailing edge is not applicable. My 9a uses a riveted trailing edge wedge with separate top and bottom skins.
 
Squeezing the trailing edge of the light wing is in the instructions, but seems to be considered the last resort. I have a light right wing (or heavy left wing) and I'm probably going to squeeze the aileron as I can't see anything else that might be causing it - however a small misalignment can have a huge impact on balance at 180kts.

My QB ailerons are kind of "fat" at the trailing edge, so I have a lot to work with. I want to set up some very consistent tests so that I know when I've "fixed" it, and have not yet taken the time to do that. Perhaps I just need to squeeze a very small bit, fly, and see how it feels. Probably overthinking it.

My aircraft also likes a bit of left rudder at speed to keep the ball centered - no idea if this is related.

While changing the T/E shape can create turbulence and therefore address wing heaviness, I suggest other ways. Changing the T/E shape will increase or decreases control response. Much better to read section 5 and get the T/E into a position where the skins sit flat, like the pics in that section. Then if hinge slotting is not working, add a wedge on the bottom of the aileron so it is not visible.

When I started my IFR training in the 6, I noticed a very sensitive elevator. Went back there one day and tweaked all of the elev T/E's to the optimum shape and the sensitivity was reduced. Still very responsive, but more like what Vans designed. It made holding altitude easier in my training. Clearly the mis-shaped T/E's were increasing elev sensitivity.

FYI, the OP has a 9 which does not have a rounded TE.

Larry
 
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Squeezing the trailing edge of the light wing is in the instructions, but seems to be considered the last resort. I have a light right wing (or heavy left wing) and I'm probably going to squeeze the aileron as I can't see anything else that might be causing it - however a small misalignment can have a huge impact on balance at 180kts.

SNIP

Exactly correct. Here again Van’s assumes everything else is properly rigged and the builder just failed to get the right trailing edge radius. This is trivial to the more common rigging issues I discussed on my earlier post. But - some builders just jump on this, grossly deforming their ailerons without getting the results they expected.

Carl
 
Almost all responders (save one) have assumed the aileron trailing edges on the RV-9(A) are folded like the -6, -7, -8. They are NOT! All trailing edges (ailerons, flaps, elevators, rudder) on the -9(A) are overlap riveted to an AEX aluminum extrusion. The OP should realize most of the advice here relates to the -6, -7, -8 style of folded trailing edges. Squeezing, bending the -9(A) trailing edges will not help the heavy wing. There is something else out of alignment. One item that has not been suggested to the OP is check that the landing gear leg fairings are properly aligned.
 
Hi Larry,
Would you mind giving me a call on this issue. My RV-7 flew hands off for 500 hours until I dropped a wheel into a colvert and the left wingtip hit the ground (as did the prop). Now that it's back together, its a really heavy left wing. I'm working my way through VANs website tech support letter, but thought you might have insight. Marty Heller KSUT, 703-732-3264
 
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