It has been so long since I completed the right wing, I am questioning the process and order of skinning the wing. I have squared the wing and secured it using two lengths of angle stock bolted to the W.S. 0, and the rear spar attach hole., so that should be set and locked in. After removing twist with the wing vertical I then tried it with the wing horizontal, and I decided it was more secure for me to do it horizontally - the way that the Sonex instruction sheet PDF shows (SNX-W07-02). In the Sonex instructions they state to pilot drill and cleco the upper aft skin to the flange on the rear spar (after aligning the edge of the skin to the edge of the spar flange and clamping in place). I have done this. I believe the center line on the rib flanges are fairly well aligned with the wing skin holes for the most part.
The Sonex instructions say to then (step 6) “make sure the wing is still twist-free and begin to drill and cleco the skin to the wing ribs …”
Now that the skin is covering the spars, how can I verify the wing is twist-free? Do I remove the clecos holding the skins to the TE, temporarily move the skin and check level at root and tip one more time?
What is the best way or order of drilling/clecoing the skin to the ribs - one hole in each rib at at time and work forward from the TE, or start from the root/rib #1, or the middle of the span (rib 7 or so) and work evenly in both directions from there … etc.?
The spars should be blocked up and leveled before you start. Find a way to secure the wing spars to the table and blocks so they won’t move. That’s how you ensure they are true. So you do the aft and leading edge skin, then flip it over. Repeat your leveling, and you will need different blocks. Do the other aft skin and then do the ratchet straps for the leading edge.
I would do one row at a time, from back to front. All ribs get the aft most hole drilled and clecoed, then move to the next set of holes forward.
I did the tops first. They are more critical for aerodynamics and aesthetics, so especially for riveting if there is any funkiness make sure it ends up on the bottom.
I’ll see if there are pictures in my old thread or my collection.
Thanks for the info and the photos. That helps. I also found a link to Jeff Shultz’s build log, and his page for wing skinning. He did his vertically and I might give that method one more attempt.
I used a cheap, pen style presentation laser pointer to ensure there was no twist. Shoot it through center of the tooling holes for a quick check of rib position before skinning per Sonex instructions (did mine horizontal as Brian describes).
I spent some time in the hangar today looking at this and thinking about what might go wrong if I attempted to do it vertically. I settled on doing it horizontally as the factory shows and you all recommended. Spent some time verifying that my platform itself was level, and tops of spars were level after blocking/shimming, and clamped in place. Skin back in place and clecoed at the TE, and verified level again. Drilled and clecoed the top aft skin up to but not including drilling into the main spar (that is tomorrow’s job, plus flipping it over to put the bottom aft skin on). Everything lined up fairly well with only slight tweaks needed in a few spots.
One little hiccup was on rib #9 when drilling one of the holes the drill rubbed right up against the aileron bellcrank support bracket. Looks like I will need to do some clearancing on that area of the bracket to make room the the tail/shop head of that one skin rivet.
That’s awesome! I worked with Les and Kyle at Schweizer before Sikorsky destroyed the company. I used to own a 1-35C. I flew with Nutmeg Soaring in Connecticut and flew in Freehold NY for a while. When we moved to the Elmira area I was at Harris Hill. I miss it.
