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Fuselage bottom skin to wing bottom overlap

dbaflyer

dbaflyer

Well Known Member
I am working on the right wing right now and where the bottom fuselage skin overlaps the bottom wing skin (#8 screws to hold) the fuselage skin does not fit flush with the bottom wing skin. This is looking from underneath the right wing toward the fuselage. 2/32nds and 3/32nds gaps

FuselageBottomSkinToWingBottomFit1.JPG
 
That's not too bad

It's been a while since I worked on this for my 6 but iirc I had same issues and didn't know how to fix it so I left it as is. It's on the bottom parallel to the airflow and being that I was getting oh so close to flying didn't want to put much time into something so hidden and inconsequential.

It may be more visible on a A model though. Perhaps others will offer better suggestions than I. Good Luck!
 
What is your current spacing ? If you push down in the middle .. will it lay flat then ?

I have not done this part on mine (RV6 slow no hole) yet ... when I do .. and if I have the same problem.. I would look at two things ... put a shim strip of lets say .025 or .032 .. along the full length - and or .. add another screw and nutplate in the middle ......
 
It might fit better if the fuselage is on the gear,looks like its on a cradle?might take some of the stress off of the bottom skin.
 
I had the same problem with my 9A (sitting on the gear) when I mounted my left wing last week. I broke the edge over just a bit with the edge rolling tool and it's much better now.
 
To get my wing incidence equal, I was up against max edge distance on the rear spar on one wing. As a result, the bottom of the fuselage and the bottom of the wing don't match up very well on that side at all. Uglier than yours by far. I'll not be encouraging anyone to crawl under my plane at fly ins! :eek:
 
If you have access to a metal shrinker you can mount it on a jack and shrink the metal a little and get a perfectly flush fit
Be warned that the shrinker will mar the aluminum
 
Wing Bottom Overlap

If it really bothers you then respace your rivet holes and start on one end and push the skins flush with each other each time you drill a hole. By starting at one end you will maybe wind up with a little more material to trim. You might even have to use more rivets more closely placed to get it to keep laying down flat. Just extra work.
 
unclelar said:
If it really bothers you then respace your rivet holes and start on one end and push the skins flush with each other each time you drill a hole. By starting at one end you will maybe wind up with a little more material to trim. You might even have to use more rivets more closely placed to get it to keep laying down flat. Just extra work.
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It's not rivets, it's screws.

I'm guessing the overhang is about 2 inches, and the dihedral is about 3.5 degrees? If so, trigonometry tells us to expect about 1/8 inch gap IF the bottom of the wing is perfectly even with the bottom of the fuselage. I'm in the middle of prepping parts for the center fuselage, and just this past weekend used Cleaveland's edge forming tool on the sides and aft end of the bottom skin this weekend. If rolling the edge doesn't stiffen it enough to prevent the pillowing (I suspect it may not), I'll go back and add screws.
 
longranger said:
It's not rivets, it's screws.

I'm guessing the overhang is about 2 inches, and the dihedral is about 3.5 degrees? If so, trigonometry tells us to expect about 1/8 inch gap IF the bottom of the wing is perfectly even with the bottom of the fuselage. I'm in the middle of prepping parts for the center fuselage, and just this past weekend used Cleaveland's edge forming tool on the sides and aft end of the bottom skin this weekend. If rolling the edge doesn't stiffen it enough to prevent the pillowing (I suspect it may not), I'll go back and add screws.
Click to expand...

If that is the case the fix should be simple.

Create a gentle 3.5 degree bend in the 2 inch overhang starting at the edge of the fuselage.
 
az_gila said:
If that is the case the fix should be simple.

Create a gentle 3.5 degree bend in the 2 inch overhang starting at the edge of the fuselage.
Click to expand...

I thought about that, but the problem is that the bottom of that part of the fuselage isn't flat, it's the same shape as the bottom of the wing. If you bend the overhang toward the inside of the curve, the edge will have to shrink somewhat. I think that MAY be the cause of the pillowing between the screw holes.
 
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