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Heavy wing

Bavafa

Well Known Member
Just wondering if anyone has a solution to a heavy wing for the RV14?
I have a heavy wing on the right side and it is within my aileron trim range but I would like to fix it if I can.

I have double checked my rigging and the ailerons are set pretty darn precise using the provided jig. My method of checking is to set the jig on one side/aileron and hold that aileron in a fixed position then moving the jig to the other side, it comes to a perfect match. Then the flaps are set to the same level in relation to the ailerons on both side. When they are fully retracted, they are about a hair lower than the ailerons. I am not so much interested in adding a wedge to the aileron if there is other methods that can be done.

In other RV models (6/7) we can squeeze the aileron trailing edge or replace the hinge bracket which is bolted to the ailerons but in 14, they are riveted and not easily replaceable.

I was wondering if any other things can be checked/modified to get a more balanced setting in roll?

As always appreciate all thoughts and suggestions.
 
I think the -14 wing is like the -10, if so, you?re doing it backwards.
1. Flaps up should be against the aft spar.
2. Ailerons match flaps (make sure elevator is neutral)
3. Adjust tips to match ailerons.
4. Sight down the wing, front to back, checking that both ailerons are the same vertical height at their leading edges. If this needs fixing either slot the mounting bracket(s) or buy new, undrilled ones.
 
is the ball centered?

Have you checked that your ball is centered in level flight. That will give you some insight into whether or not there is a yawing moment, that could be causing the heavy wing.
 
I would need to get confirmation on this from others as I am not familiar with the 10s setup but with 14, as part of the kit, we get a jig that you use to setup the aileron to the neutral position.
Next time I am at the hanger, I will check to see where is my elevator when my aileron are in the neutral position.
As for my flaps go, they are pretty much as high as they will go. One side (pilot side) goes up another half a degree or so but now I have set them to match.
 
I think the -14 wing is like the -10

Like is the operative word. He is not doing it wrong from what I can tell from his write up.

The 14 is provided with two jigs, one to ensure the aileron bell crank is in the neutral position while using the other to set the aileron. The wing tips are also set with the aileron alignment tool so they match the aileron neutral position.

The flaps are set so that when fully retracted, they are at -7? relative to the upper longeron. This is easy to do with a digital level.

Setting both the ailerons and flaps per the 14 plans yielded a great result on my airplane.

Not advising this since I have no idea as to whether this a good idea for the 14, but on my Sonex, the accepted cure for a slight heavy wing was to lower the flap on the heavy wing a half turn on the rod end bearing. I used this procedure on my Sonex and it fixed the slightly heavy wing issue.
 
Have you checked that your ball is centered in level flight. That will give you some insight into whether or not there is a yawing moment, that could be causing the heavy wing.

Hi Jared,
Yes, I am good with the yaw, the ball is centered pretty nicely
 
Not advising this since I have no idea as to whether this a good idea for the 14, but on my Sonex, the accepted cure for a slight heavy wing was to lower the flap on the heavy wing a half turn on the rod end bearing. I used this procedure on my Sonex and it fixed the slightly heavy wing issue.

Bob,
I thought of doing that but I guess that is adding some additional drag that otherwise wouldn't be there. I may still play with that to see if no other ideas come to mind. Would you lower it on the heavy wing or the light side? If you lower it on the heavy side, wouldn't that create a bit more lift?
 
flaps should be set to the wing and nothing else. measure from a rivet on the wing to the trailing edge on the flap and set the same on both wings.
 
put the flaps in the up position. select a rivet on top of the wing and measure with a scale to the trailing edge of the flap. set the opposite side to same measurement. flaps should be set to the wing not to anything else. you might think, it's not possible to measure this way, but it is.
 
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Wedge is an easy fix

Guys,

Please don't flame me, you more technical guys, about a "proper" fix ?
Just trying to help a fellow RV pilot with a cheap, easy, and reversible solution.

A very easy fix for my heavy wing which could not be trimmed out with the manual trim, was a small piece of trailing edge Balsa wood affixed to the underside of the aileron of the LIGHT wing. That location may seem counter intuitive. But that's the way trim tabs work and the wedge is in effect, a trim tab.

We tried various lengths with both tanks full and fuel load balanced until it flew perfectly level with the manual trim lever and stick centered.

About a 6" length fixed the heavy wing for us in our RV4. There was no detectable change in speed, but the plane was noticeably more pleasant to fly.

Held in place with white Gorilla tape and is virtually invisible being on the underside of the aileron and the white tape matching our white aileron.
(Gorilla tape does come in a variety of colors and seems strong enough to survive at least mach 2 speeds)

The biggest issue was finding a place to buy the trailing edge balsa wood. Once I found a vendor I had to buy way more than I needed (i.e. several 3 FOOT lengths) but it was cheap. If you PM me with your address and contact info I would be more than happy to send you a three foot length.

FYI ? My RV4 is a plane which I did not build. I bought it last March. We suspect the heavy wing is the result of some hanger rash where the previous owner dented an aileron on a hanger door. The intent is to re-skin the damaged aileron over the nasty flying weather months of January/February in this part of the world. But for now this was a great solution.
 
So where on the aileron do you tape the wedge? Towards the root or tip, front or rear (trailing edge).

-Marc


Guys,

Please don't flame me, you more technical guys, about a "proper" fix ?
Just trying to help a fellow RV pilot with a cheap, easy, and reversible solution.

A very easy fix for my heavy wing which could not be trimmed out with the manual trim, was a small piece of trailing edge Balsa wood affixed to the underside of the aileron of the LIGHT wing. That location may seem counter intuitive. But that's the way trim tabs work and the wedge is in effect, a trim tab.come in a variety of colors and seems strong enough to survive at least mach 2 speeds)
 
Positioning the Wedge

So where on the aileron do you tape the wedge? Towards the root or tip, front or rear (trailing edge).

-Marc

Marc,

I don't think the positioning laterally (towards root or tip) matters much since the purpose is to move the entire aileron. However I chose to put the wedge laterally toward the center of the trailing edge of the aileron on the bottom of the light wing, straddling one of the stiffeners of the aileron.

Orientation front to back the wedge is positioned with the thick portion of the wedge aligned with the underside of trailing edge of the aileron.


As previously mentioned, putting the wedge on the underside of the light wing may seem counter-intuitive (at least it was to me initially), but this is indeed the correct position. i.e. For a heavy left wing causing the plane to bank left, the wedge goes on the underside of the right wing aileron.

In taping the wedge to the aileron I chose to tape over the entire wedge, as opposed to using double sided tape or permanently mounting it with epoxy or silicone seal as other posters have mentioned in other threads.

i.e. The tape starts about a quarter inch in front of the thin portion of the wedge on the underside of the aileron to make a smooth transition from the aileron to the wedge. The tape then extends over the thick part of the wedge terminating on the top side of the aileron with about a quarter inch of tape showing on the top edge of the aileron. Thus the entire balsa wedge is enclosed in tape and protected from the elements.

Is this clear? I'd take a picture but as I mentioned in a previous post the repair is virtually invisible with the white Gorilla tape closely matching the white paint of the aileron.
 
i have used a wedge on a different type of plane to trim it and i put the wedge over an underlying structural part of the aileron. it is exerting force.
 
Bob Turner laid this out in post #2. Add point number five, that the elevator has to be set in the neutral position.
Before you try wedges etc, raise the flaps up all the way by adjusting the linkage. Do the ailerons line up with the flaps? If not then adjust them. Do the wingtips line up with the ailerons? I suspect you will find one, or both wing tips are not lined up.
Some have used the jig and it works fine, but it did not in your case. The jig is definitely used to set the aileron bell crank in the correct location

Please take the time to try this method
 
Wedges, tabs, and straws.

Excellent help here and I only have two heavy wings repaired so a novice. In my 7 journey, I read about the straw trick. This is just for debugging and interest. The post said to use a coffee stirring straw, plastic, start with 4" long. Tape it parallel to the TE back about 1/2-3/4" from the edge. Use some thin tape, but masking works just as well. Put it under the light aileron. Middle- end, it does not matter, but I liked the middle. It worked for rudder yaw and aileron/heavy wing debugging to ensure the plane flew straight with it installed. It was pretty effective and easier than making a wedge or tab for experimentation.

It works like a wicker bill. A Gurney flap. Look at NASA's evaluation of what Dan Gurney discovered while racing if you want to know the science behind it.

Can anyone post a picture or email to me a screen capture of the new hinge design??

So who cares about tabs, wedges and straws? Why?? I found 3 kts (or at least I think I did ) with the heavy wing fix on my 7. If that does not matter, then just tab-wedge-straw it.
 
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Bob Turner laid this out in post #2. Add point number five, that the elevator has to be set in the neutral position.
Before you try wedges etc, raise the flaps up all the way by adjusting the linkage. Do the ailerons line up with the flaps? If not then adjust them. Do the wingtips line up with the ailerons? I suspect you will find one, or both wing tips are not lined up.
Some have used the jig and it works fine, but it did not in your case. The jig is definitely used to set the aileron bell crank in the correct location

Please take the time to try this method

As mentioned in the post, the alignment has been checked and rechecked but not in relation to the elevator and I am planning on checking that this weekend. However, please help me understand this that if the elevator was to cause deflection of the ailerons, wouldn't than you expect the plane have a wing heavy in climb or decent if it was rigged correctly in neutral?
 
If neither the flaps or ailerons have any twist in them, and everything is rigged correctly, the deflection that occurs on the ailerons when the elevator is moved, happens equally on both sides. It occurs because the control column that each aileron push/pull tube is attached to is moving fore/aft, changing the distance between the control column and the aileron bellcranks very slightly. The change is very small.

Not I said if the flaps and/or ailerons have no twist in them.
The advice given so far is good, but if you are checking alignment of ailerons and flaps and some of them are twisted, you will not get a proper result.

On the RV-14 and 10, the leading edge of the flaps are designed to be lightly touching the rear spar at the inboard end when fully retracted.
Once this is adjusted, the rivets in the top flange of the flap spar should all be the same distance aft of the top wing skin trailing edge. If they are not, then there is a twist in the flap.
You can also check for twist by placing a digital level on the inboard and outboard ribs of the flap or aileron. If twist is found, the it will have to be compensated for , when doing the control system rigging (I.E., don't align an untwisted aileron to the outboard end of a twisted flap.......)
 
Scott is absolutely correct. I had been in the shop thinking about your issue and it occurred to me that a slight twist in one or more of the control surfaces could also cause a trim imbalance.
Two things to try. Line up the surfaces on both wings and pull a string from the inboard flap end and extend it out to the outboard edge of the wing tip. This should show any twists in a surface. Check both wings at the same time so that you can compare side to side.

Another option is to clamp a long piece of angle to the surfaces and see if everything is lined up. It would not take much of a twist in an aileron to make a difference in flight.
 
Thank you both Tom and Scott for the additional info.

As part of my re-checking the rigging, I checked for twist in both flaps and aileron. Not an easy thing to check but this is what I observed using digital level and looking straight thru the trailing edge of aileron/flap.

The digital level showed minimum twist (it was fraction of a degree) and it varied as measured at different part of the flap. I mostly accounted for that as part of variation in the skin deflection but there was no appreciable change from the extreme inboard to extreme outboard and this was true for both sides.

My left flap can go slightly higher than the right side before it hits the stops. I have adjusted the left to be at the same level as the right when it is fully retracted and it is only the thickness of a paper lower than aileron at neutral position. I had not checked for the elevator position when I was checking these.

One thing I need to check to see if I have the newer jig with the reflex hole which is noted in the manual or the older style. It seems it should not matter since both L&R were used using the same jig but nevertheless.

Finally, I might just need to stop being anal about it as the heavy wing is within the trim margin, but if I could get it to fly straight with the trim in the middle, that would be awesome.
 
I don't know the differences between the 14 and the other RVs but I like to connect the aileron trim system "after" I have flown the plane to confirm everything is OK. This way I can be sure the trim system is not bias one way or the other.
 
My right wing was also slightly heavy but within trim range. Used my caliper to measure the aileron thickness half an inch from the trailing edge at each rib and found the left wing to be 34 thou thicker on average than the right. Squeezed the left side down at the thicker rib locations and it corrected the heavy wing.
 
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My right wing was also slightly heavy but within trim range. Used my caliber to measure the aileron thickness half an inch from the trailing edge at each rib and found the left wing to be 34 thou thicker on average than the right. Squeezed the left side down at the thicker rib locations and it corrected the heavy wing.

Yes, squeezing the trailing edge is a very effective way of addressing the heavy wing but this is mostly on the model that has a bend trailing edge as oppose to riveted ones.
 
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