Building the rib jig for the Baby Great Lakes Biplane

The following photos are self explanatory. The plans for the biplane come with both a template and coordinates and the builder can choose the best method. I decided to use the coordinates and I laid them out using a dial caliper and a pencil.

I then screwed down blocks the represent the spar openings. The wings on a Baby Lakes Biplane are unique because the top wings are swept at 6 degrees while the bottom wings are straight. One rib jig is used for both wings. That's accomplished by inserting shims next to the spar openings before assembling the ribs on the rib jig. I used brass shim stock available at any hardware store.

The nose ribs are pre-glued to the upper and lower capstrip so take that into consideration when building the rib jig. Instead of nailing down pieces to held the parts in place I simply used 2 long pieces of wood and followed the contour of the coordinates that define the airfoil shape and nailed them down. For the inside pieces I hammered some nails down and cut the heads off with a side cutter. Very simple and very easy.

Here are the photos of the rib jig. You will notice the red ink I used to draw where the wing rib gussets go. I did this so I could take a knife/file and open up the jig where the glue could potentially touch the jig. The makes it easier than cleaning the glue on the jig after I remove it.

You will also notice that I drove nails next to the spar blocks. I'll explain that in a different post but basically I ground some wedges on the disc sander and that holds the vertical pieces tight against the spar blocks.

Here are the photos of the rib jig for the Baby Great Lakes Biplane.