Webb

Webb

Well Known Member
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I was talking to an old A&P about wing heavy the other day and his response was something I haven't seen or at least read enough posts.

His comment was to adjust a flap and that is what he recommends and does. Somethings as little as one turn of the pushrod. It will keep your stick centered with no trim tab. Last but not least, doesn't mess with your paint job like squeezing the trailing edge. It would also be an extremely easy adjustment in an RV.

What about it guys?
 
This is certainly an option, but...

Adjusting a flap to be down in the wind stream increases drag, and since it in inboard, it is not as effective as an aileron.
 
If the flaps are not rigged properly, and that is the cause of a heavy wing, then yes I would agree. If the flaps are rigged properly, then the cause is other than the flap, and Mel is correct - you'll add drag to cover up a symptom, rather than solving the problem.
 
I did it 9.5 yrs and 1065 hrs ago. Adjusted one of the flaps down maybe ~0.4-0.5 degrees. Slows the plane a little (has to be a fraction of a kt), but it sure was easy to do and is reversible.
 
Webb said:
I was talking to an old A&P about wing heavy the other day and his response was something I haven't seen or at least read enough posts.

His comment was to adjust a flap and that is what he recommends and does. Somethings as little as one turn of the pushrod. It will keep your stick centered with no trim tab. Last but not least, doesn't mess with your paint job like squeezing the trailing edge. It would also be an extremely easy adjustment in an RV.

What about it guys?
Click to expand...

Webb,
I agree with Mel and Greg about adjusting the flaps.

Check your ailerons at the outboard hinge. Is the heavy wing aileron a little high there? Mine was. The steel hinge bracket that bolts to the aileron can be slotted with a file in a few minutes to lower the aileron. I lowered mine about 1/8" and it flies hands off now. This must be a common problem as I read about it here I think.

Mark
 
How do you guys check height here? What's the reference? Can someone post a step-by-step procedure that leaves no assumptions... aka.. the way you'd explain it to a 3-year-old... thanks!
 
Mark Burns said:
Webb,
I agree with Mel and Greg about adjusting the flaps.

Check your ailerons at the outboard hinge. Is the heavy wing aileron a little high there? Mine was. The steel hinge bracket that bolts to the aileron can be slotted with a file in a few minutes to lower the aileron. I lowered mine about 1/8" and it flies hands off now. This must be a common problem as I read about it here I think.

Mark
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In the words of George Strait, "don't think that I'm trying to mind your business, it's a full time job just trying to mind mine", but slotting the wing attach holes is a significant modification to that component.

2 cents tempered with 20+ yrs of mechanical engr experience
 
Twisted Aileron?

I have a slight twist in one aileron - one trailing edge tip is about 3/16" higher than the other.

How will that affect the mix? Should I re-skin or will it be lost in the other noise?

Jim Sharkey
RV6
 
jsharkey said:
I have a slight twist in one aileron - one trailing edge tip is about 3/16" higher than the other.

How will that affect the mix? Should I re-skin or will it be lost in the other noise?

Jim Sharkey
RV6
Click to expand...
I have about 1/4"-5/16" twist in one of my 8-foot flaps (in other words, about the same as in your aileron). Ken Scott told me just to fly with it and see what happens. Everything might balance out he said. It might be that the only reason I would need to rebuild the flap would be for aesthetic purposes.

I'm also one of those people who would think twice about slotting an aileron without permission from Van's. If I remember correctly, their published fix for wing heavy is a combination of trailing edge squeezing (for those models that have a squeezable trailing edge) and flap adjustment.
 
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Steve,
I wouldn't worry about 1/4" of twist aesthetically.
Most people park with the flaps down, in which case no one will know unless you point it out. And if anyone notices it in flight, well, they're just too close anyway.
 
Check other options first!

My ailerons were litterly "flying" different. I had a heavy right wing, but when the ailerons were in perfect trail, from either the trim tab or slight pressure on the stick, the plane would fly level in roll.

Then I discovered that the left aileron had a slightly thicker radius than the right. Some slight squeezing of the thicker left aileron accomplished the trick. My plane is now perfection in regards to trim.

Had I changed a flap setting, it would indeed have added drag; and been the wrong course of action; although it would have solved the basic problem.

L.Adamson ---- RV6A

edit: P.S. --- I have good paint, and the squeeze didn't damage the paint at all.
 
Do it the easy way.

Low Pass said:
In the words of George Strait, "don't think that I'm trying to mind your business, it's a full time job just trying to mind mine", but slotting the wing attach holes is a significant modification to that component.

2 cents tempered with 20+ yrs of mechanical engr experience
Click to expand...

I agree don't slot it. That is a makeshift way to fix it.

I lost one of the o.b. brackets somewhere in my garage after so many years:confused:.

I bought a couple of them, they were less than $5.00 each.:)

They only had the pivot hole in them

If you are going to slot it, just do that to figure where to put the holes in the new one.

You want these to be sturdy and predictable under any gust or unusual load.
 
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Mel said:
Adjusting a flap to be down in the wind stream increases drag, and since it in inboard, it is not as effective as an aileron.
Click to expand...


Who says you have to make the heavy wing "lighter" by adjusting the flap down if you want to fix the problem and reduce drag all you have to do is put the lighter wing flap up further. Less flap in the wind is less drag.
 
Mel said:
Steve,
I wouldn't worry about 1/4" of twist aesthetically.
Most people park with the flaps down, in which case no one will know unless you point it out. And if anyone notices it in flight, well, they're just too close anyway.
Click to expand...
Oops, I guess I just pointed out my error! If anybody does get that close and complains, though, I'll send them to you, Mel!:D

Thanks, though. For the last couple years I've wondered what kind of builder I am if I just accepted that twist. Now after almost 4 years, however, I don't care anymore. I just want to get done and fly. Any flap-aileron mismatch will have to wait for another (post-first flight) day!
 
TSwezey said:
Who says you have to make the heavy wing "lighter" by adjusting the flap down if you want to fix the problem and reduce drag all you have to do is put the lighter wing flap up further. Less flap in the wind is less drag.
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First, I think that if you can adjust a flap "up", they probably weren't adjusted correctly. The flaps on an RV come up against the fuselage when in the retracted position.
Second, if you CAN adjust the flap "up", I don't think you will see much effect. You can try it, but I don't think it will work. Let us know.
 
Mel said:
First, I think that if you can adjust a flap "up", they probably weren't adjusted correctly. The flaps on an RV come up against the fuselage when in the retracted position.
Second, if you CAN adjust the flap "up", I don't think you will see much effect. You can try it, but I don't think it will work. Let us know.
Click to expand...

I haven't flown yet so I don't have a problem yet but I believe the inboard edge could be trimmed. I was just adding some fuel to the debate. I would probably adjust the aileron if it were my plane. The aileron has a bigger moment arm so you would need less lift/drag to level the plane.
 
Low Pass said:
In the words of George Strait, "don't think that I'm trying to mind your business, it's a full time job just trying to mind mine", but slotting the wing attach holes is a significant modification to that component.

2 cents tempered with 20+ yrs of mechanical engr experience
Click to expand...

Bryan,
I never said anything about slotting the WING ATTACH holes!
I said slot the aileron hinge bracket. It's a factory approved method to determine where you need to be. Heck, Dan Checkoway even did it:D
http://www.rvproject.com/20050508.html


See Van's document here: http://www.vansaircraft.com/pdf/Wing_Heavy.pdf

Mark
 
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Mark Burns said:
Bryan,
I never said anything about slotting the WING ATTACH holes!
I said slot the aileron hinge bracket. It's a factory approved method to determine where you need to be. Heck, Dan Checkoway even did it:D
http://www.rvproject.com/20050508.html


See Van's document here: http://www.vansaircraft.com/pdf/Wing_Heavy.pdf

Mark
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Odds are very good it won't cause a problem. Maybe going from seven "9"s of reliable to six "9"s. But if it did fail, the consequences would probably be very bad. It's just beyond my comfort limit. Happy flying.
 
No more wing heavy

Just 3 twists (total - not each bearing) of the rod end bearings on the flap eliminated the heavy wing. After inspection of the change, the right flap quit touching the fuselage before the left did when retracting. Case closed.
 
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