Luis & Fab's RV-7A Construction Log

Once both spars are ready to go, the next step is to prepare the ribs that hold them together.

Two of the ribs need to have their flanges cut up so they fit in the spars. I used the sheet metal shears to remove most of the material, followed by the scotch-brite wheel and emery cloth to smooth out the edges.

Because of the manufacturing process, the ribs end up with a bit of a warp on them. They need to be straightened out before installing them. To do this, I used fluting pliers to make small flutes (d’uh) on a couple of places. This makes the ribs nice and straight. In the two pictures below, you can see how the rib warps upwards, and how the hand-seamer is used to straighten it up. You can see a finished rib on the background, sitting flat against the table.

After trimming the flanges off the spar, it also needs to be bent at a six degree angle. I was afraid of over-bending it if I used the vise, and a hand seamer tool is not long enough to bend at the ‘bend line’. So, I just set the spar on the workbench, with a piece of 2×4 over it (see below). I then used two small pieces of 2×4 held in my hand to ‘grab’ onto the web, and bend it. The result is shown on the next picture.

After bending the spar, I assembled it with the two reinforcement angles, and drilled all the rest of the holes. The final result is shown below.