Chapter 19 - Step 4

This step has you assemble all the cores of a wing and added the shear web.

Foam in the Jigs July 5, 2003. It was time to test fit the cores into the wing jig. Wow, is the wing big. These shots show the wing jig I built. I made a base to attach the jigs to so it would be easier to get everything level. The garage floor is sloped a good bit so it is much easier to prop up the end of the base. The base has some small boards attached at the proper butt lines that the jigs can be clamped to.

July 5, 2003. Another shot of the right wing in the jigs.

The Whole Wing July 5, 2003. One more shot of the wing in the jigs.

July 5, 2003. Here is a shot of the wing jig clamped on the base. You can see I used thick particle board for the jigs and the base. This makes it more sturdy and the jigs actually stand up straight on their own.

LWA Recess July 9, 2003. Here is the recess for one of the LWA hardpoints in the wing root.

July 9, 2003. This is the bolt access recess. The notch at the top is for the LWA hardpoint.

Bolt Accesses July 9, 2003. A shot of both bolt access recesses. This is looking straight down from the top of the shear web face.

July 11, 2003. Here is the completed bolt access. You can see the aluminum hardpoint at the top, the aluminum cover in the spar cap trough and the access recess with the BID layup in place. I didn't have the real thin aluminum on hand so I grabbed a roll of aluminum tape and stuck about 5 layers together - seemed to be about the right thickness. I then cut it to size and stuck it in place with 5-minute epoxy.

Shear Web August 9, 2003. I finally was ready and had the time to do the long shear web layup. It took me 7 hours to micro the foam, add the six layers of UNI, attach the leading edge cores, add the BID and LWA's, and add peel ply where needed. After the second layer I discovered I only cut 4 each of the UNI strips instead of 6. Oops. Had to stop in the middle and cut the extra glass.

Nothing too hard here, just tedious getting each piece of UNI layed out properly, 45° angle, and trimming it to fit properly. I found it easiest to layup in place and get one edge even with the spar cap trough edge then trim the other side after getting the piece all layed out nice. This worked best for all the wing root end pieces since there was little extra width. For the pieces near the wing tip, I just centered it and trimmed both sides since there was plenty of extra width in the glass.

The only other thing I wasn't sure about was attaching the two metal LWA's. It appears you glue these on with an overhang so the edge of the metal (the rounded edge) will be even with the top of the spar cap when it is added. I hope I placed them correctly. It certainly seems like it would be easier to add these after doing the two spar caps but they must be on before glassing the top or bottom of the wing so it would require a few extra flips of the wing. OK, maybe not easier after all.

August 9, 2003. Once thing I will do different on the other wing - I chose to attach the leading edge cores after adding the shear web - while everything was still wet. Days earlier I had test fit the cores and sanded the mating surfaces a bit to minimize any gaps between the cores. I had them near perfect. So now, after 5.5 hours of adding the shear web, I grabbed one core, added a bunch of micro and stuck it in place. No problem. I grabbed the other core, added a bunch of micro and stuck it in place. Problem! There is a bit of a gap between the two leading edge cores. They touch at the bottom but the gap increases toward the leading edge. Too late to deal with now. I guess the shear web layup changed the angle of the cores slightly or the cores warped a bit since I last test fit them. I now have a gap to fix before I glass the wing. Next time (left wing) I will attach one leading edge core then test fit and sand the other core as needed - then attach it for a better fit.