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I have the infamous heavy wing

danny

Well Known Member
sigh....seems my left wing is pretty heavy. I haven't checked rig, aileron hinges, etc but I don't know if I should do much more than a taped on tab for know. I don't have gear leg fairings or wheel pants yet so shouldn't I get those on first?
I do have the wheel pant mounts on and that may even be part of the problem.
Any advice or ideas?
danny
 
What airplane? Folded trailing edge ailerons or riveted?
I would recommend against "fixing" the problem by installing the fairings. Two wrongs don't make a right!
 
I had a moderately heavy wing too.

It's fairly fast to check your aileron rigging and well worth doing.

It took longer to check my gear leg fairings, but I jacked up the plane and dropped plumb bobs and carefully remeasured and adjusted by a quarter inch.

I still had a heavy wing and added a wedge cut from a block of 3/8" x 1.5" or so hard wood. I used heavy duty double-sided tape under the aileron. It's easy to start long and cut it shorter until you are satisfied. I think mine was about 6" long when all done. It stayed attached fine through Phase 1. I added two pop rivets before painting.

David
 
If it's a model with a bent not riveted trailing edge, a common cause is an aileron that isn't exactly flat but instead puffed out. You really want those to be flat -- if they're not then it can not only cause a heavy wing but higher stick forces overall. Lay a straightedge several places on each aileron and iteratively squeeze the trailing edge where it's puffed out. Concave? No prob. Just bonk the bend with a rubber mallet (don't overdo this though! :eek: )
 
Hi
I had the same but Vans have a troubleshooting guide to work thru ,this should be the course taken ,and I did end up squeezing my trailing edge 👍
 
I just helped a guy with a 6A address this. His had a heavy left wing. P/O had put a trim tab on and lowered the left flap almost an inch and it was still wing heavy. After addressing the issue properly, the plane now flies straight and flies 6-8 knots faster. Flaps now in trail and tab gone.

1) ensure trailing edge is bent properly by looking for flatness in the skins (no concave or concex skins). Well documented in Section 5, including remediation steps. This step skipped with riveted T/E's

2) ailerons rigged to tooling holes with elev neutral. Verify that flaps are aligned ailerons. You need to pull up on them to remove the linkage slop/play while measuring, as that is where they will go in flight. Just insure that the linkage cannot hold them below the ailerons. They can drift upwards into reflex without any real penalty.

3) get a long straight edge and start looking for mis-alignment of the alieron hinges. If memory serves, A low aileron hinge point will make that wing heavy. Search here as discussed many times. In the remediation effort described above, I only had to move one hinge ~1/8" for all of the improvements. That is a lot. Needed two test flights to dial in the adjustment.

No reason to wait for fairings and likely better to do before. Fairings tend to impact yaw, but enough yaw will induce a roll.

Larry
 
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Time to check my rigging.

Thanks for the suggestions. VAF people never disappoint.
I put a very temporary tab on the right aileron and still have lots
of other stuff to checkout. It's only flown three times.
Next week looks like rig checking...weather going South.
BTW, it's a 9 so trailing edges are riveted.
danny
 
I’ve help other RV builders/owners fix heavy wing problems. In every case there existed a rigging problem needing to be first be resolved.

Here is the short version of how to go about checking your rigging:
- Are the flaps really all the way up and trailing edge flush with he fuselage - and both sides the same? I found one RV-4 that had a low flap for 20 years.
- Taking a straight edge over the wings and extending out over the flaps, do you have the same gap over both flaps, and over the length of both flaps (as in no twist)?
- After you address the flaps, now look at the ailerons. With the trailing edge of one aileron lightly clamped to the trailing edge of the flap, is the other aileron trailing edge lined up with the other flap? If not fix this before moving on.
- With the ailerons now lined up with the flaps, measure the aileron to wing skin gap across the length of the aileron. Is it the same? Are both ailerons the same. Typically this is the problem area. The fix is to re-hang the offending aileron - either by replacing the offending hinge with a “no hole” hinge from Van’s and drilling a new hole in the right spot or elongating the hinge to aileron bolt holes to have an adjustment up or down.
- After you do all this, then look at the wingtips on how they line up.

For builders, this last point is why I recommend deferring wingtip fit up until after the wings are on the plane and this rigging is done. “Lining up tooling holes” only gets you in the ball park.

Carl
 
- After you address the flaps, now look at the ailerons. With the trailing edge of one aileron lightly clamped to the trailing edge of the flap, is the other aileron trailing edge lined up with the other flap? If not fix this before moving on.
Carl

For this step make sure the elevator is clamped neutral. First time, I forgot.
 
One more thing for you to check. Relative to the shorter-wing RV's, the flaps on a -9/9A are REALLY long and are REALLY hard to build with absolutely no twist because of that. There's a good chance that even if your ailerons are perfectly straight and lined up with the tooling holes, that some (even slight) twist in the flaps will cause some roll effect. What could make that worse is if the builder chose to align the ailerons with the full up flaps for aesthetic reasons rather than the tooling holes as Van's instructors. Then you have two reasons for roll.

You can check for flap twist by putting a digital level on the inboard and outboard ribs of the flap. They should read the same.

FWIW, I have some of the above. One flap at the outboard trailing edge is about 1/4" lower than the properly aligned aileron even while being flush with the bottom of the fuselage at the inboard trailing edge. That said, I'm able to trim it out with the manual spring trim just like I do with fuel imbalances anyway, so I'm not too concerned about it.
 
heavy wing....

I removed the wingtips and aligned the ailerons with the tooling holes and lined up the flaps with the ailerons. The right flap wasn't totally snugged up to the belly and the left aileron is maybe 3/16" lower than the tip. I haven't checked for twisting and haven't measured the hinges...I'm not sure I totally understand what to do to measure the hinges. Looks like saturday will be a good day to start measuring though since it's threatening to rain.
The VAF brain trust is a great resource...thanks, all.
danny
 
I'm not sure I totally understand what to do to measure the hinges.
danny

Stand in front of the wing, ailerons both neutral, and sight down the top of the wing. Does your sight line flow smoothly onto the top of the aileron? Or is the leading edge of the aileron higher, or lower? You can do a little better with a 2’ metal straight edge, but your eye is pretty good. Compare left and right sides. A 1/16” difference in height will definitely cause a heavy wing (high aileron on heavy wing). As Carl said, slot the hinge mounting holes as need to move the leading edge to ‘in trail’ with the wing. Test fly. Permanent fix is to buy no-hole hinge brackets from Vans, drill new holes in the right place.
Note: I understand the latest kits are different, you may need a different adjustment procedure if your hinges are attached differently.
 
aileron is high on one end

Well I finally took some measurements and found the l/h aileron outboard end is about 3/32" higher than the inboard end. Is this enough to make the left wing heavy? Tanks are full so next flight is all on the left tank to try to get some weight off of that side. I don't want to slot the hinge bracket until I'm 100% certain on what the heck I'm doing.
BTW, r/h aileron measures the same as the l/h inboard.
Any thoughts?
danny
 
Well I finally took some measurements and found the l/h aileron outboard end is about 3/32" higher than the inboard end. Is this enough to make the left wing heavy? Tanks are full so next flight is all on the left tank to try to get some weight off of that side. I don't want to slot the hinge bracket until I'm 100% certain on what the heck I'm doing.
BTW, r/h aileron measures the same as the l/h inboard.
Any thoughts?
danny

Yes. This is exactly the same as my -10. Getting that left end bracket 1/16” lower made a huge difference.
 
Well I finally took some measurements and found the l/h aileron outboard end is about 3/32" higher than the inboard end. Is this enough to make the left wing heavy? Tanks are full so next flight is all on the left tank to try to get some weight off of that side. I don't want to slot the hinge bracket until I'm 100% certain on what the heck I'm doing.
BTW, r/h aileron measures the same as the l/h inboard.
Any thoughts?
danny

3/32 is a lot for hinge alignment and certain to cause an issue. You want to measure the gaps at all four hinges and strive for consistency. Both high AND low cause problems/imbalance. You want all four to be consistent.

Larry
 
it took me about 10 flights to get all tested and finalized. As suggested try 1/16 at a time and fly for a bit to make sure it is balanced.

I ordered new hinges w/o holes and made a jig to match drill the holes using the pivot as its datum.

The last tweaking was done with aileron squeezing adjustments.

You can quantify the imbalance (if you are sure the roll spring is out of the equation) in gallons by filling and flying on one tank until happy. This gives you the chance to confirm results at the end, or in the middle if things get muddy.
 
- Taking a straight edge over the wings and extending out over the flaps, do you have the same gap over both flaps, and over the length of both flaps (as in no twist)?

Using a straight edge, I’ve discovered that my right flap is lower than the left. It’s about a 3/8” gap, VS a 1/4” or less gap on the right flap. The problem that I see, is that the flap is all the way against the fuselage fairing. I guess that need to be removed and re-fit? Is that possible without drilling a bunch of new holes?

222C8A73-8634-46C9-9651-BB9868AE7F04.jpeg
 
Using a straight edge, I’ve discovered that my right flap is lower than the left. It’s about a 3/8” gap, VS a 1/4” or less gap on the right flap. The problem that I see, is that the flap is all the way against the fuselage fairing. I guess that need to be removed and re-fit? Is that possible without drilling a bunch of new holes?
View attachment 11643

Flap misalignment is not nearly as critical as aileron misalignment. The flaps don't have near the leverage of the ailerons.
 
Using a straight edge, I’ve discovered that my right flap is lower than the left. It’s about a 3/8” gap, VS a 1/4” or less gap on the right flap. The problem that I see, is that the flap is all the way against the fuselage fairing. I guess that need to be removed and re-fit? Is that possible without drilling a bunch of new holes?

View attachment 11643

Ignore the fairing for now (the fairing may be misleading). Is the bottom of each flap up tight against the bottom of the fuselage? If so then done. If the low flap is up as high as it can go, then you have option to lower the other flap to match. This may not be your final fix but it will help isolate the heavy wing issue.

After you address the flaps, not go look at the ailerons.

Carl
 
I've got a heavy left wing as well. It's been this way since I bought the plane 4 years ago. As I did not build the plane I'm looking for someone who can help perform the required corrective work with/for me.

The left wing is heavy even with full corrective mechanical trim, which is the position the manual trim lever is always kept at. In this fully-trimmed condition, the roll tendency balances out after using ~8-9 gallons of fuel from the left tank after started with full tanks. The plane is certainly completely flyable as is, but it handles even better when the roll imbalance is fully balanced out.

I've read the Van's corrective procedure, done the straight edge check, and believe some of the aileron hinges may need adjustment and the aileron linkages could also use a bit of adjustment.

I just don't have the tools or aircraft modification experience to perform this work myself in the manner and timeframe in which I would like it done.

I'm based in Durango, CO and will gladly fly to wherever I need to in order to get this work performed. Please kindly PM me with any suggestions.
 
I've got a heavy left wing as well. It's been this way since I bought the plane 4 years ago. As I did not build the plane I'm looking for someone who can help perform the required corrective work with/for me.

The left wing is heavy even with full corrective mechanical trim, which is the position the manual trim lever is always kept at. In this fully-trimmed condition, the roll tendency balances out after using ~8-9 gallons of fuel from the left tank after started with full tanks. The plane is certainly completely flyable as is, but it handles even better when the roll imbalance is fully balanced out.

I've read the Van's corrective procedure, done the straight edge check, and believe some of the aileron hinges may need adjustment and the aileron linkages could also use a bit of adjustment.

I just don't have the tools or aircraft modification experience to perform this work myself in the manner and timeframe in which I would like it done.

I'm based in Durango, CO and will gladly fly to wherever I need to in order to get this work performed. Please kindly PM me with any suggestions.

If you don’t get any reply’s, and you’re willing to fly a few hours, Synergy air in Oregon would likely be able to help subject to their availability. They are experts in RV’s.
 
Anyone have any data on how a gopro on the opposite wing will affect a "heavy wing?" Or if someone was fully balanced, and they added a gopro, what effect did it have?
 
I've got a heavy left wing as well. It's been this way since I bought the plane 4 years ago. As I did not build the plane I'm looking for someone who can help perform the required corrective work with/for me.

The left wing is heavy even with full corrective mechanical trim, which is the position the manual trim lever is always kept at. In this fully-trimmed condition, the roll tendency balances out after using ~8-9 gallons of fuel from the left tank after started with full tanks. The plane is certainly completely flyable as is, but it handles even better when the roll imbalance is fully balanced out.

I've read the Van's corrective procedure, done the straight edge check, and believe some of the aileron hinges may need adjustment and the aileron linkages could also use a bit of adjustment.

I just don't have the tools or aircraft modification experience to perform this work myself in the manner and timeframe in which I would like it done.

I'm based in Durango, CO and will gladly fly to wherever I need to in order to get this work performed. Please kindly PM me with any suggestions.

If you want to fly to Chicago, I can do it. I helped a new RV owner go through the same thing with the aircraft he purchased. His heavy wing is gone and picked up several knots as well (P/O had over an inch of flap deployed on one side to overcome the tendency.

Larry
 
heavy wing no more

Just to bring closure to the original post.... I ended up putting a small trim tab on the right aileron and it flies the way it was intended. There's still a misalignment between the left wing tip and the left aileron but nobody will notice and I can fly without the distraction. The input was very much appreciated.
danny
 
Anyone have any data on how a gopro on the opposite wing will affect a "heavy wing?" Or if someone was fully balanced, and they added a gopro, what effect did it have?

Mine is balanced and it makes no difference at all.
 
Anyone have any data on how a gopro on the opposite wing will affect a "heavy wing?" Or if someone was fully balanced, and they added a gopro, what effect did it have?

Makes zero difference on my -6.
 
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If you want to fly to Chicago, I can do it. I helped a new RV owner go through the same thing with the aircraft he purchased. His heavy wing is gone and picked up several knots as well (P/O had over an inch of flap deployed on one side to overcome the tendency.

Larry

A few weeks ago, on the good advice of Walt Aronow, I installed one of Steve Melton’s 3D printed wedges under the right aileron. Heavy wing problem 100% solved. 👍

I also had a bit of left yaw and a couple of wedges on the left side of the rudder fixed that too.

The wedges are unobtrusive and do not affect overall plane appearance. They are an excellent solution.

I permanently attached the wedges with 6 minute set-time JB Weld epoxy. But I first flight tested them attached with tape only.
 
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