Right top skin and leading edge
TLDR
- Completed right top skin prep
- Completed right (outboard) leading edge prep
- Clecoed right leading edge to the wing
- Started riveting
Top skin
Prep
Top skin prep = clean, dimple, debur etc.
On Friday I already cleaned the skin and started dimpling, so I just finished dimpling yesterday. Comparing to bottom skin, the top skin is pretty easy. It only needed a single line of 4.0 counter skin, and a single 3.2 countersink.
Clecoing
My dad helped me carry the skin onto the spar. Then I clecoed the skin to the spar assembly. 99% of the holes fit together nicely. A few looked out of alignment slightly.
Leading edge
Prepping
Spent an hour or so: deburred, cleaned, and dimpled where necessary.
I went ahead and dimpled the holes that’s supposed to hold the pixie glass for landing light. I realized only after dimpling that I needed to match drill some holes on the pixie glass first. Fortunately it’s probably not a big deal since the glass is transparent. When the time comes I will put the pixie glass on top of the aluminum and draw the matching holes that way. But maybe when I build the left wing I will leave the dimpling to later, just to make things easier.
Fitting to the wing
From watching Evan’s video, I know I needed to fit the skin from the bottom, then roll it to the top. Boy that was definitely easier said than done.
The skin is pretty thick, and the fit is incredibly precise, so on my first try all the holes on the top were like half a hole off. Obviously not accetable.
So I did this again with help from my dad. While he held the skin like a human clamp, I clecoed every single hole from the bottom so the skin and ribs fitted as tightly as possible. This worked much better. When we clecoed all bottom holes, the top 4.0mm line almost matches the countersink holes on the main spar but not quite. I started to cleco the “best fit” holes using the black celco, and one by one they started to fall in position.
In the end, we clecoed almost all holes to make them align. I expect some match driling in this area when it’s riveting time.
Main spar countersink doubler
So there is a strip of think aluminum under the leading skin that’s supposed to sandwich the main spar with the leading skin.
When fitting the leading edge, my main focus was to get the main spar and skin holes align. I did not pay attention to this doubler strip. With leading edge in place, I went back to re-cleco it under the main spar while making sure all holes are aligned through each and every cleco.
This also too a while to complete, mainly due to the extreme tight space I had to work with. I had to use a borescope to look under the skin to check if the doubler strip is clamped down by the clecoed. The good news is that it is.
Rivet
4.8MM x 10 MM rivets rant
Somewhere near the root There is a row (42) of 4.8mm x 10mm rivets.
This is by far the lowest quality parts I have worked with on this kit.
On every other kit components, the parts are either fairly polished or comes with very slight burs. However the 4.8x10 rivets are the opposite of polished.
Every single rivet I was sent comes with significant burs, and required deburring in order to fit into the holes. It’s quite unacceptable and makes me wonder if Sling received a batch of counterfeit parts or something.
In any case, I had to debur the rivets to insert them to the holes.
Planting rivets
I spent like hours to plant all rivets. Like I said earlier most rivets went in position smoothly. A few required some wiggling to go in. 6 required match drilling. Considering there must be 800 or more rivets, I think 6 matching drilling is fine. I have not done the leading edge or fuel tank yet. I expect to match drill a few more if necessary.
Riveting
I measured the jig twist one more time before committing to rivet. To ensure the jig absolutely stay in shape, I riveted the main and rear spar first, then moved onto ribs, starting from root extending outwards.
I was at rib 7 or 8 before my Milwaukee M12 rivet gun started to acting up. I constantly had to pull the trigger two times or more for it to catch to stem. The gun is pretty hot at this point. I first suspected the battery was low. But after changing batter it’s the same. I wonder maybe it’s overheating internally and causing some kind of alignment issue with the mechanical parts? IDK.. I will let it rest for a while before trying again.
