Old Build (flying) - Flap/Aileron Alignment

Hello all. Below is a plane I purchased. I did my research but being a first time buyer and RV owner, there were things I didn't notice initially which an experienced builder/-4 guru would have. Live and learn. A very brief history--this is an older build (first flight in 1983) and the logs show that it was disassembled in 1998, reassembled in 1999 by Ray Williams and sold in 2000. It has accrued ~700/hrs since this point. Whether this is relevant or not is hard to say but is worth mentioning.

To the point--you can see in the first few images below (left inboard/outboard) that the trailing edge of the flap/aileron/tips don't align. I don't see this as being very significant but just making note of it. I attribute it to being a very early build and the attention to detail that I see in these new RVs that look like certified aircraft (ya'll have some beautiful RV's!) just wasn't there with the early builders/kits. However, the right flap/aileron alignment is off considerably and yet, the inboard of both L/R flaps meet the fuse the same.

The kicker? Airplane flies hands off, which I imagine is why I didn't notice it initially. The RV grin obscured my view. What you see in the images is what the plane looks like in S+L flight. The stick is centered as well. I attribute this to the manual trim tab on the left aileron that is compensating for this.

So curiosity is getting the best of me. What's the root cause here? It's ugly and isn't up to the standards I see on the forums here, but should I be concerned? I imagine it's been flying at least 700/hrs like this (since re-assembled) and possibly more, perhaps even built this way? Thoughts?


Left - Outboard


Left - Inboard



Right - Outboard


Right - Intboard

Are the the control surfaces twisted? To have that much deflection, something must be way off. In S & L, my control surfaces all line up, no trim tabs.

In the picture of the left outboard, the gap between the wing and aileron is not constant. It looks like the builder lowered the hinge point to line up with the flap. On the right wing, it almost looks like the flap is not "up" all the way. I would find a local 4 builder to look at it.
Do you have the build manual and drawings?

Nate-ISU said:

Airplane flies hands off, which I imagine is why I didn't notice it initially. The RV grin obscured my view. What you see in the images is what the plane looks like in S+L flight. The stick is centered as well. I attribute this to the manual trim tab on the left aileron that is compensating for this.




Left - Inboard

Right - Intboard

Click to expand...

First off, as you say it is flying hands off---good. Most likely due to the trim tab.

The aileron and flap trailing edge shape is a big factor on these planes, and from what I can see in your photos, the trailing edge appears to bulge outboard of the trim tab in the first photo, and the flap trailing edge looks a bit strange in the outboard end in the second photo-----photos that I have copied above. These could be photo distortion, or actually the trailing edges being not uniform across the entire surface-----this would be a good thing to check. Check out this thread http://www.vansairforce.com/community/showthread.php?t=132215

Unless this is a really big issue to you, you just might be better off to enjoy how it flies, and accept how it looks. If you go after getting the looks top notch, you may end up chasing a lot of newly induced gremlins in the handling side of the equation.

Non-uniform TE

The non-uniform trailing edges were a possible 'feature' of the early kits caused by tolerances in the not yet pre-punched parts.

This is from the early RV-6 instructions on fitting the flaps...



I'm sure the RV-4 instructions were similar.

It looks like the builder didn't purchase the wider hinge. In my case I needed it on one side and not the other.

Appreciate the comments up to this point!

Are the the control surfaces twisted?

Not that is visible from the eye that I can tell. I could place a 2x4 or similar across the surface and check whatever gap there may be but if it were twisted to such a degree to cause that sort of alignment issue, I believe it'd be easy to see with the naked eye. Unless I'm mis-understanding your question.

Do you have the build manual and drawings?

I have the original plans & logbooks. No documentation/pictures of the build process.

It looks like the builder lowered the hinge point to line up with the flap. On the right wing, it almost looks like the flap is not "up" all the way

Good observation on the aileron. As for the flap not being 'up,' I agree, that's exactly what it looks like--but it definitely meets at the fuse consistent with the left flap and there is no play if you attempt to 'pull up' lightly on the flaps when fully retracted as they are here. That's what boggles my mind; visually, it looks as if it needs to retract further, but any more and it would be far above where it meets the fuse, just 'moving' the problem.

Unless this is a really big issue to you, you just might be better off to enjoy how it flies, and accept how it looks.

Other than looking ugly, its apparently been flying this way for years and like I said, flies hands off so I can't complain other than the visual aspect (assuming it's not a safety of flight issue--asking those sorts of questions are like asking for legal advice on the internet, I need to just speak to a builder) My plan has been to fly it until FWF needs something major then strip it down and fix the nuances but thought it was worth fielding the questions to this awesome community.

If you like the way it flies, and it's all about looks, it's simple to fix. Park with the flaps down....

Measure

Pictures and eyeballs can be deceiving.

Set the flaps and ailerons to what you think is neutral (or the flies straight) position and get a digital level and measure both the flaps and ailerons at 6 inch intervals from root to tip.

This will show any left/right differences and also measure any twist in the control surfaces.

Older builders used to see this sort of thing quite often. There was very little networking among builders or good examples to follow.
If the integrity is there, the build is safe and it flys well, I would not be to anxious to open up the possible huge can of worms to just make it look better. It may end up being a ton more work than anticipated
Back then We noticed right off that the builders of these planes had just as much fun as ones that looked better cosmetically.
Like Ironflight said, Park it with the flaps down like most of do anyway and enjoy the plane.
of course I am assuming that this plane has had many conditional inspections and found in a condition for safe flight. Have fun, Spring is here.
Larry

the course

here is what i would do...
turn on the shop radio to 50'S music , sit in a chair with feet up on something , crack open a beer, and sit and stare at the issue. stare at the whole thing for a while, you may arrive at the problem some time later and when you are at that point go look at the plans closely and you may find where things went off script. and how it got that way, then make a call to vans and ask questions, and also post here.
plan b...
enjoy it and dont get attached to it, leave the option open to sell it and get one that is more to your standards. and enjoy it while you have it..
billythekd, collecting parts, gaining knowledge, learning

Fifties music will slow your plane down. Try the Ramones instead.

Love the suggestions! I think they are spot on. I've personally had her through three condition inspections now. I never really saw it as unsafe but curiosity finally got to me and I had to ask. I'll keep feeding her avgas and grinning all the while!

It looks to me like your left aileron might be a bit low. I changed the ailerons on my wife's RV-4 (hangar rash). Van's sells pebuilt RV-8 ailerons that fit right on. I also installed new Vans made hinge pieces that are U shape 4130 steel. These are pre-drilled and the aileron fit was a lot better to the wing. It flies better now too. These hinge pieces are the key to fitting the aileron to the wing. They are not expensive and removing the aileron from the wing to alter or replace them is not difficult.
One way to tell if an aileron is low: fly in the rain. The normal or high aileron will be clean on top. The low aileron will have standing water droplets sitting on top. My RV-8 is that way, but the roll to the right is so slight that I just burn off the right tank first.
A funny note; When I had the left hand turning Mazda Rotary engine / prop, the trim was perfect. Go figure.

Only thing I can think of is that the right rear spar was installed upside down. It's easy to do if you build them both at the same time and even the build manual warns against this. They have you build the left wing first, which turns out correct but while you're at it you build the right wing spars at the same time and to look the same. (It's a heavy duty project.) But you have to look closely at which side is top and bottom. Or even know there is a top and bottom. Ask me how I know.
Check the rear spar attach points on both side and see if they're drilled to the carry through in the fuse the same. Do the wing tips fit nicely on both sides or does one sit a little differently than the other?
edit: Heck, worst case scenario you have an upside down left wing on the right. The plans only show the left wing and you have to mentally build it opposite for the right.

joeboisselle said:

Only thing I can think of is that the right rear spar was installed upside down. It's easy to do if you build them both at the same time and even the build manual warns against this. They have you build the left wing first, which turns out correct but while you're at it you build the right wing spars at the same time and to look the same. (It's a heavy duty project.) But you have to look closely at which side is top and bottom. Or even know there is a top and bottom. Ask me how I know.
Check the rear spar attach points on both side and see if they're drilled to the carry through in the fuse the same. Do the wing tips fit nicely on both sides or does one sit a little differently than the other?
edit: Heck, worst case scenario you have an upside down left wing on the right. The plans only show the left wing and you have to mentally build it opposite for the right.

Click to expand...

How can you put a rear spar in upside down at assembly time?

The two flanges are bent in opposite directions, one at 82 degrees and the other a 95.5 degrees. Since one is more than a rt angle and the other is less, the 13.5 degree difference is noticeable and the wrong flange will fit for c**p against the ribs...

Flaps/alerons alignment

Nate-ISU said:

Appreciate the comments up to this point!

Are the the control surfaces twisted?

Not that is visible from the eye that I can tell. I could place a 2x4 or similar across the surface and check whatever gap there may be but if it were twisted to such a degree to cause that sort of alignment issue, I believe it'd be easy to see with the naked eye. Unless I'm mis-understanding your question.

Do you have the build manual and drawings?

I have the original plans & logbooks. No documentation/pictures of the build process.

It looks like the builder lowered the hinge point to line up with the flap. On the right wing, it almost looks like the flap is not "up" all the way

Good observation on the aileron. As for the flap not being 'up,' I agree, that's exactly what it looks like--but it definitely meets at the fuse consistent with the left flap and there is no play if you attempt to 'pull up' lightly on the flaps when fully retracted as they are here. That's what boggles my mind; visually, it looks as if it needs to retract further, but any more and it would be far above where it meets the fuse, just 'moving' the problem.

Unless this is a really big issue to you, you just might be better off to enjoy how it flies, and accept how it looks.

Other than looking ugly, its apparently been flying this way for years and like I said, flies hands off so I can't complain other than the visual aspect (assuming it's not a safety of flight issue--asking those sorts of questions are like asking for legal advice on the internet, I need to just speak to a builder) My plan has been to fly it until FWF needs something major then strip it down and fix the nuances but thought it was worth fielding the questions to this awesome community.

Click to expand...

I just aligned both mine. I too did not notice it because mine also flew hands off.
It was brought to my attention by Carl "Wizard" Froehlich.
Note: when the flaps are down also check to make sure there is a thin stop nut at the bottom of the flap eyelet.
Can't see from your pictures.

I also saw no canopy hold open mechanism.
Install one, or risk loosing your canopy when the engine is running, even 1" open is enough to rip it clean off. Also the string will not hold it if the canopy is open and another aircraft starts in the vicinity, or even a strong gust.

Daddyman
N262 DF almost 200 hrs now on a 1996 model
Dues paid

az_gila said:

How can you put a rear spar in upside down at assembly time?

The two flanges are bent in opposite directions, one at 82 degrees and the other a 95.5 degrees. Since one is more than a rt angle and the other is less, the 13.5 degree difference is noticeable and the wrong flange will fit for c**p against the ribs...

Click to expand...

\

Upside down backwards works. You don't really notice till you start stapling skins down and your aft rivets don't hold the skin flush to the spar.
But this explains why his ailerons have a difference of around 13.5 degrees. I did this 15 years ago, fresh out of a&p and my FIRST right wing looked exactly like this.

See about getting a set of Preview Plans. They will give you enough info to determine if (where) things were put together wrong.

The flap spar may have been installed upside down. The top flange is 99-1/2 Deg., and the bottom 96. If the right flap hinge was installed on the 99-1/2 this would cause the flap to drop down further when controls are neutral.

It is not easy to see the 3-1/2 Deg. difference between flanges when the spar is on the bench, and requires careful study to get the correct flange on bottom. The best way to think of it is you need the bend that is closest to a 90 on bottom, and the more open bend on top.

The problem with the left flap trailing edge not in alignment is due to builder possibly not waiting to install top flap skin until mounting flap hinge to flap brace on the wing. Plans call for waiting to drill top skin which produces the trailing edge until this point which allows builder to get trailing edge aligned with aileron. At this point small alignment changes could be made with both the hinge, and trailing edge of top flap skin.

[/IMG]

Wow--this is fantastic everyone. RogerG, thank you for that image!

Very interesting. I still have the plans rolled up, I'm going to take a closer look at them and see if I can get the mental picture in my head. I'm sure the flap has to come off before I can see anything of value; perhaps more--\can't really tell with the attached image and am having a hard time 'seeing it' in my mind so I'll roll out the plans tonight and take a closer look to see if it's something that I can confirm/deny without getting very invasive/taking skins off, etc.

Measure

Nate-ISU said:

Wow--this is fantastic everyone. RogerG, thank you for that image!

Very interesting. I still have the plans rolled up, I'm going to take a closer look at them and see if I can get the mental picture in my head. I'm sure the flap has to come off before I can see anything of value; perhaps more--\can't really tell with the attached image and am having a hard time 'seeing it' in my mind so I'll roll out the plans tonight and take a closer look to see if it's something that I can confirm/deny without getting very invasive/taking skins off, etc.

Click to expand...

Before you disassemble use a digital level and measure each control surface every 6 inches or so.

It's hard to eyeball twist and left/right differences.

az_gila said:

Before you disassemble use a digital level and measure each control surface every 6 inches or so.

It's hard to eyeball twist and left/right differences.

Click to expand...

Agreed. I don't plan on taking anything off immediately. It would appear this plane has been flying for hundreds of hours in this configuration--in light of recent information, perhaps built this way.

I've always found it easy to buy new tools, so a digital level, which I currently lack, sounds like an easy purchase that can be used many times over.