Now I’ve resolved the retract installation issue I was able to finish up the structure of the left wing fairly quick. First, I’ve glued in the shear web for the retract (rails) which you can see here:

And this picture shows the completed retract mount and cutout rather well, you can see there’s not much left of the rib the retract’s sitting in, but nonetheless it’s still quite strong:

Time to prepare the control surfaces sheeting for the wing. I had to make four aileron sheets, two upper flap and two lower flap sheets. They are cut out from stock 1/16″ balsa using the patterns provided on the plans and then the edges are beveled so they could be joined at the trailing edges. The first line on each sheet indicates the bevel and the second one marks the end of the ribs:

Then I cut and added the shear webs to the back side of the main spars:

And sheeted the flap:

Sheeting the control surfaces isn’t difficult but you need to come up with a technique to hold the sheeting in place while the glue is curing (since I’m not using CA whenever I can). First, I’ll check how the sheeting should be fitted:

Then I use aliphatic resin (white wood glue) to glue on the upper aileron skin (the wing is upside down on the building board). I use packaging material which is quite spongy to hold the sheeting in place, when pressed under the wing, this will press up the sheeting against the ribs. Of course, doing so would lift the wing of the building board so I need the weight of a few batteries to hold the wing down:

Might not look very professional, but it sure works! The lower sheeting is glued with the same glue and held in place with pins and batteries while curing, here’s the end result:

Which means I’ve finished the structure of the left wing, so I’ve removed it from the building board:

After trimming off the tabs (except W1 and W11) and sanding both the spars and the sheeting flush with the root rib, I could turn it around and clean it up:

Time to clean off the building board and pin down the plans of the other half of the wing and repeat all steps, which should go faster as all prep work is done already. As we speak the ribs of the right wing are curing being glued to the upper spar already.