Mounting ribs

Ribs, so many ribs.

It's not so much fun repeating a task over and over again.  Once figuring out how to do it, the process does get faster the second, third, and fourth time, however.  This gets easier when coming across weird problems, like this rib that needed to attach right at an aileron hinge bolt.

I finished epoxying the ribs to the right wing and am just six trailing edges away from finishing the left wing too.  It takes about fifteen minutes to prep a few ribs, sanding with dull 220 to give some tooth, cleaning with mineral spirits (for any leftover masking tape adhesive) and isopropyl alcohol, and clamping the fiberglass tape in place.  For the first several, I epoxied the aluminum then wrapped the fiberglass to pull the epoxy up through the fabric like is proper.  The glass is such a loose weave and wets out so nicely that I began to pre-stage the material and then wet out generously to see that the epoxy contacted the aluminum surface.  I can't tell a difference in the bond quality, and this is a non-loaded bond, as the fabric will tend to hold the ribs in place anyway.  It takes another fifteen minutes to mix a small batch of epoxy, wet out the four staged rib attachments, ensure they're nicely soaked in, and clean up.  After four hours or overnight, I come back to trim the excess fiberglass tape.  A quick sanding with a block flattens any raised surface texture, being careful not to cut the underlying fibers.

I also filled in a couple mis-drilled holes with spare bolts.  As I understand, it's improper to leave a hole, and putting a bolt to fill the hole is an acceptable repair.  In both of my cases, there are other bolts nearby that will bump out the covering, so it isn't a big deal to cover over another bolt head / nut.

At some point, I replaced the aft cabane tube.  The upper cabane compression strut needed to be replaced, or so I thought.  The old ones were in perfectly good shape, just needed to be mounted.  Instead of fishmouthing new ones, the old ones were gently wedged into position, mounting end marked, a new hole placed there, and new washers riveted in place.  To install that strut, some minor pressure to pull the aft cabane tube away lets the compression strut to be slid over the washer mounts either end, and the pressure released.  Fits great, and was a lot less work than making new ones.


This Goat project is getting close to being done.  I don't have any additional planned metal work.  The leading edge shells need to be mounted and sanded and glassed, and that should finish off the required composite work.  I could fair the struts with foam and fiberglass, though that is optional for a maiden.  Then it's really just load testing and covering (in that order).