Aft inboard ribs

I put this step off until the center section spar was installed... mainly because I wasn't looking forward to this step of Chapter 19. It requires (and I quote from the plans) "surgery".

First, I had to read the plans 6845354681351 times to understand what is happening here.

So after studying the drawings, and making a few assumptions.. I discarded the "core" of the aft inboard rib and began conducting the required "surgery".

This is the left wing... upside down. I used a knife to remove most of the foam... but was then left with a bunch of micro on the fiberglass... this needed to be removed.

Using a dremel, I sanded the micro off. Much easier said then done! Especially in the tight space!

The plans don't specify how to trim the aft end of the rib. So I went through a bunch of pics that I have taken over the years at airshows and just made a transition from rib to wing... sort of like making a mold for a bow of a ship... think of a bathtub with a rounded "V" corner...

0.6" on top and bottom for a nice glass-to-glass bond...

After a lot of carving, sanding, prepping, micro scraping, cursing the canard gods, etc... it was time to cut some BID. I love how the plans then say "now layup a 3-ply rib in the entire area"... as if it were that simple!

Origami time! I now had to figure out how to best cut the fiberglass so it would fit inside the shell and fold/overlap properly. I came up with the following shape. The black lines are cut lines..

Fold along the red dashed lines... and I get a rib!

So I cut 3 of these ribs out (layup #7)... and the UND strips with LWA 7 (layup #8) since those get applied while layup #7 is still wet:

Ok, it's go time! Plain epoxy on the cured fiberglass, slurry on the foam, dry micro to fill the voids, flox around LWA 6, etc...

I didn't bother to carve out the local section for the CS132L belhorn for now... I didn't know how much to remove so I will remove it later with a dremel and do a small BID patch when it comes time to install the aileron pushrods.

All hands were busy installing the origami ribs, so I did not take pictures of the actual layups. Long story short, I used a brush to "tuck" the ribs in place.

After all 3 ribs were installed, I applied the 3 UNI strips over LWA6, installed LWA7 over them, and clamped it in place. I used a small piece of peel-ply over LWA7 to prevent the clamp from bonding to it.

 I should note here that I did the left wing (port wing) horizontal and the right wing (starboard wing) vertically - it was MUCH easier with the wing in the vertical position (shown below) since it helped lay the ribs without them falling over! Lesson learned.

Next day, I trimmed everything up and prepped the LWA7 area for the 1-ply BID extending 1" all around... 

Notice the flox fillet around LWA7 under the 1 ply BID...

Next day, trimmed everything nice and flush!

The aft end of the rib will get a 2-ply BID wall with flox corners sometime in the future...

And there you have it! Aft inboard ribs complete!!! The wings are ready to be installed onto the center section spar!

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