Got to the part where you're supposed to reach in and rivet the leading edge ribs to the spar with AD4 rivets. At first when I saw where I had to maneuver the rivet gun, hose, and my mits, I thought this was Van's cruel joke on us. Spent a good amount of time looking at the LE, studying the plans, and doing some searches here. A lot of builders seem to have gone the route of using pull rivets but I wanted to stick to the plans and figure this puzzle out.
Well, the end result is all of the rivets are set and I couldn't be happier. Manufactured head is inside against the thinner rib material as is recommended. Each rib took a different configuration of where to run the hose and where to run my arm, so I took some notes along the way in hopes it helps a future builder. I know there are some other similar posts here on this topic but I thought I'd contribute my experience.
Some general things that helped:
- Need a swivel air inlet on the back of the rivet gun. I don't know how I would have done this without it.
- Use a straight hose, don't horse around with those coiled ones.
- Double offset rivet set is obviously a must.
- I used a 2X rivet gun because it was smaller and fit in the tight space, and just increased the pressure a bit to compensate.
- I'm going with the duckworks leading edge light system, and having the big holes already cut in the LE skin helped immensely.
- A little dental inspection mirror is very handy. Many times you need to line up the set onto the rivet without any visual. Cell phone camera also helps to do the final inspection of the manufactured heads.
- I needed a partner for some of the ribs.
- I lucked out and have skinny arms. Your elbow should be able to fit THROUGH the forward-most hole in the leading edge rib for this method to work.
Detailed configuration for setting each rib, outboard to inboard:
Rib 14 (outboard-most): Hose runs through leading edge light hole, stand towards outboard end of the wing, right arm runs through leading edge light hole, standard grip on rivet gun, can be done solo.
Rib 13: Hose runs through forward-most lightening hole in rib 14, stand towards outboard end of the wing, left arm runs through leading edge light hole, standard grip, can be done solo.
Rib 12: Hose runs through leading edge landing light hole, stand towards outboard end of the wing, left arm runs through leading edge forward hole then forward hole in rib 13, grip rear of of rivet gun with palm, needed a partner to buck.
Rib 11: Hose runs through forward holes in ribs 14-12, crouch down on bottom side of wing, left arm runs through the inboard-most lightening hole in the spar, grip rear of rivet gun with palm, can be done solo.
Rib 10 (this was the most challenging one): Hose runs through forward holes in ribs 14-11, stand towards inboard end of the LE, reach WAAAAAAAAAAAY in with left arm, through the forward rib holes in ribs 9 and 10. I needed to go so far my elbow was through rib 9. Glad I didn't get stuck. Not much leverage/power with your arm extended so you need to really make sure the set remains securely against the rivet. Grip rear of rivet gun with palm. I pretty much pulled the trigger and prayed, doing these. Definitely need a partner to buck.
Rib 9: Hose runs through forward holes in ribs 14-10, stand towards inboard end of the LE, left arm goes through forward leading edge rib 9 hole, grip rear of rivet gun with palm, can be done solo.
That was it. Take your time and make 100% sure each of those rivet heads are correctly seated in the set. Check them. Double check them with the mirror before pulling the trigger. You don't want to have to drill any of these out. My wife learned to buck rivets during this exercise so that's a bonus that'll come in handy later.
Hopefully this is helpful to some future VAF searcher.