March 4 - June 9, 2001

Building a Rib Jig and Wing Ribs

When I visited the factory I picked up a box of parts and straight aluminum angle stock, along with some drawings. The first thing I needed to do was make a jig for the ribs.

Here's what I came up with. The holes are just big enough to fit a couple of short pieces of spar tubing. There are slots for the bottom angle of the rib "widgets" to fit into so they lie flat on the wood. And there are guides for the rib cross-pieces.


This shows the spar tubing and widgets in place, along with bent upper and lower rib pieces, and the fluting tool used to make the bends.

Here's the other side of the jig, a mirror image for making ribs for the opposite wing. Chuck says it isn't necessary to make the ribs different for each wing, but it was easy enough to flip everything over.


Loading the jig with the widgets and upper and lower ribs. A piece of wood wedges things in tightly.


Cross-pieces drilled and clecoed in place.


The holes come out pretty rough... I used a large drill bit to debur them.


Riveting the cross-pieces and widgets into place.


A cross-piece riveted in place. The raised edge is bent back so it doesn't snag on the cloth (or my hand...)


A bunch of nearly finished ribs. The rear widgets aren't riveted on yet, and the lower rear cross-piece is clecoed in place until the ribs are attached to the wing frames, to allow them to fit around the drag and antidrag struts.