Top Wing Skins 16-2-1 to 16-2-3, 16-2-6
Continuing on with preparing the wing parts for assembly and riveting, I took the W-1002 and W-1003 wing skins along with the wing walk doublers, and starting with the right wing deburred the edges of one set of skins and doublers.
I then clecoed the right wing ribs and rear spar assemblies to the main spar. Next I took the set of top J-stiffeners for the right wing that had been match drilled using the main spar back in section 13, and inserted them into the notches in the wing rib top flanges. Note there are 3 holes that overlap where the J-stiffeners nest.
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| Top skin and wing walk doubler edges deburred and ready for mounting |
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| Ribs clecoed to main spar and J-stiffeners inserted into rib notches |
I carefully took the W-1002 top skin (shorter one) and clecoed it to the main spar flange where the wing ribs also attach. I was then able to insert the forward wing walk doubler behind the skin, and cleco it in place. After clecoing the J-channel to the skin, I was able to slide in the aft wing walk doubler and cleco that between the skin and the ribs. Finally I clecoed the rear spar to the skin. Everything aligned perfectly, and clecoes went in with minimal effort.
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| Inboard top skin clecoed in position with wing walk doublers also in place |
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| Wing walk doublers extend across the 4 inboard most ribs, with the J-stiffener passing between them |
With the inboard top skin clecoed, I then positioned the outboard W-1003 top skin and clecoed that in place as well. Again, I had no issues with hole alignment, although I did insert a cleco through the rib flanges on the back side of the skin so that the ribs were held in the correct position while clecoing from the outside of the skin. Note there are two rows of holes where the skins overlap, with the outboard skin sitting on top of the inboard skin.
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| Outboard top skin also clecoed in place, overlapping the inboard top skin along two rows of rivets |
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| J-stiffeners run along the entire length of the wing |
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| Holes and clecoes all lined up perfectly on initial install |
Next I marked the nutplate screw and rivet holes at the inboard edge as these need to be upsized and countersunk, and I did not want to risk drilling the wrong holes. Follow the plans carefully here as there are 3 different types of nutplates along this edge that will be riveted in!
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| Marking the nutplate hole locations along the inboard edge of the top skin |
The nutplate attach holes need to be match drilled into the rib flange. I was very careful to make sure that I held the drill as perpendicular to the skin as possible while drilling, because a few of these holes end up very near the edge of the reliefs in the rib flange.
I then upsized the screw holes, by first drilling them to #21, followed by reaming to #19.
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| A few match drilled nutplate attach holes end up very close to the edge of the rib flange reliefs, with about 1.5D edge distance |
With the nutplate holes match drilled and upsized, I then proceed to the countersink the screw holes in the forward most 7 nutplates for a #8 screw skin dimple. Due to having 3 layers of sheet metal sandwiched together, this was no issue for the #8 countersink bit. I only had to gradually adjust the depth to ensure that I did not go too deep and enlarge the original #19 hole.
You end up countersinking into all 3 layers, but only partially into the rib flange to get the required countersink depth, and all holes came out really nicely.
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| Screw holes countersunk into all 3 layers of aluminum |
The aft most nutplate screw hole will be dimpled, so only needs to be upsized to #19 at this time. I did this the same way as the other screw holes, but used a wood block to back the skin while drilling.
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| Using a wood block to support the skin while upsizing the nutplate screw hole |
Next I started countersinking all the #40 skin holes common to the wing walk doublers for a flush rivet. Again due to the combined thickness of the layers this was a relatively easy task, and once the countersink cage was dialed in all countersunk holes turned out perfectly.
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| Rivet holes countersunk into the top skin over the forward wing walk doubler |
Once all wing walk skin holes were countersunk, the entire right wing assembly was disassembled and all holes were deburred.
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| Countersunk holes seen in top skins and wing walk doublers after disassembly |
As with all tasks on the wings, this whole process was repeated for the left wing skins.
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| Left wing top skins attached, ready for countersinking the wing walk doubler and nutplate holes |
Build Hints
- I had considered dimpling the #40 holes over the wing walk doublers rather than countersinking, as others have had success doing this. However, as the 3 layers of material were almost a combined 1/8" thick, I felt comfortable countersinking as the plans suggest. Doing this I also didn't need to worry about dimples lining up perfectly, especially when having to nest 3 layers over a highly loaded, slightly curved surface
- Upon clecoing the left wing top skins in place, I noticed some oil canning in a couple of panels at the inboard end of the outboard top skin. Since the skin and rib holes were final sized, none had been drilled, so the oil canning was not a result of oversized holes. After removing the inboard top skin for deburring the nutplate holes (which also meant removing a few clecoes close to where the skins connect), and then reattaching it, the oil canning disappeared. The extra few minutes taken to re-cleco assemblies together definitely helps with issues such as oil canning and hole alignment!
Time Taken: 13.2 hours
Dates: January 19 - January 31 2024
Top Wing Skins Total Time: 13.2 hours
RV-10 Build Total Time: 593.4 hours
Priming Total Time: 50.9 hours (not included in build time totals)