Riveting Leading Edges to Spar September 23rd, 2008
Well, it’s time to start putting the wings together for the last time!
The first step is to take the previously-assembled leading edges and rivet them to the wing spar. The problem is that The holes for the leading edge ribs are so close to the main ribs, it’s hard to get a rivet set in there (or even the clecos!!) at a 90 degree angle.
After doing a lot of reading, and finding out the factory ‘allows’ the use of blind rivets, I decided to go ahead and use cherry commercial rivets for the leading edge. Because it is so hard to get even a rivet puller in there, I put the rivets in from the top (inside of the leading edge) and contorted my hands and rivet puller inside the leading edge.
Some gung ho people call this ‘cheating’, but I can’t help it but think I’d rather have a nicely pulled blind rivet than a half-assed solid rivet with dents (as well as the possibility of damaging the spar as well)
Here is a picture of what it would look like trying to drive a solid rivet. Notice the holes are so close, not even the clecoes are in there straight. Some people recommend grinding down to offset rivet set to get closer to perpendicular, but from the looks of this, I would actually have to grind down about 1/4 to 3/8’s off the gun itself to be able to get the set close to perpendicular to the spar. No thank you….
Van’s recommends LP4-3 and LP4-4 rivets, which you can’t find anywhere except at Van’s. I instead used Cherry Commercial rivets from Aircraft Spruce. I used BSP4-3 and BSP4-4, which are slightly stronger..according to the data table anyway…
After the leading edge was finished, I found it hard to get the skin to perfectly line up with the holes in the main and rear spar. Even though I have a jack made up of two blocks of wood and a screw-rod, it was still hard to get everything to match. So, with Fabiola’s help I took the wing off the jig and laid it on the table. Every hole now matched perfectly, and I think it was easier to squeeze the leading edge to spar flange rivets.
