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Wing Assembly

The Wing Assembly consists of the spars, the skeleton, and the skins.

Spars

Good countersinkYou will start the assembling the wing parts by riveting the tank attachment platenuts to the main spar.  Then you countersink the holes for the screws.  This seemed unnatural to me.  I had to read the directions a few times and look over the drawing again until I was convinced that this was the right thing to do.  It just didn’t seem right to use the platenuts as the “countersink jigs.”  But this is exactly what you need to do.  If you try to countersink without them, you will make a mess.  The spar is too thin to let you countersink without the platenuts behind.  Bad countersinkYou have to take off so much metal, that the hole will open up, and the countersink bit will start wondering.  The end result will be a countersink that isn’t round.

The wing assembly directions say to use a cut-off #8 screw to check for final depth.  If you countersink only enough to make the screw head flush, when you add the thickness of the tank skin, it won’t lay flush.  You need to dimple a scrap piece of .032 aluminum and use it to check the depth of your countersink.

Vans has you separately priming every little subassembly.  I waited until I had a few subassemblies before I primed them all together.  I did all the countersinking on the main spar, made the tie-down assemblies, and completed all the rear spar fitting and drilling before I primed everything at once.

Skeleton

My wings in jig with electrical conduit holes shownInitially I drilled only the holes in each rib for the electrical conduit. Since all the ribs don’t go in the wings facing the same way, I drilled top and bottom of each rib.  This guaranteed holes where I needed them.  Later, when I bought the Dynon EFIS and needed an AOA line run to the pitot tube, I had to go back and enlarge the forward tooling holes in the inboard left ribs.  You can see the electrical conduit holes in this picture (red arrows).

I did not rivet the inboard two ribs on each wing assembly until after the bottom skins were riveted.  The top skin would have been no problem, but it would have been tough to reach inside between the ribs to rivet the bottom skin. While you have them all clecoed together, try putting your hand between the first three ribs while maneuvering a bucking bar; it’s not easy.  The ribs were just too close together.  It was much easier to push them in from the end of the wing and rivet them in place one at a time. 

At this point, I put the wing assemblies into the jig.  See jigs for my ideas.  I spent some extra time here making sure everything was square.  The directions talk about holding up the middle of the wing until the row of rivets is straight.  This ensures the wing is straight, but not square.  I also used a level across the top of the spar, and shimmed until it was level.  Then I put the level against the end ribs and clamped them in place to ensure they were square to the main spar.  The last thing was to check that I hadn’t added any twist to the skeleton.  I dropped a plumb line down and lined up the tooling holes on the end ribs.  Only after I was sure the wing was true did I start with the skins.

Skins

After the wing assembly skeleton is square and true, the main skins can be clecoed on and all the holes drilled to final size.  You should be able to push all the ribs around if needed to line up with the holes in the skins. 

Don’t install the platenuts for the access panels yet.  You will be reaching in through the holes while riveting the bottom skins onto the skeleton, and the platenuts can get in the way or cut up your arm.

It’s now time for the tank jig discussed in Jigs.  You will use it to cleco together the leading edges.  After they are clecoed to the main spar, recheck them for square and true.  The tooling holes should again line up, and a level placed against the inboard and outboard ribs should show level.

Now it’s time to move from main wing assembly to the Wing Tanks.


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