Get ya a piece of 1/4" balsa sheet and cut it to the same rib shape as the wing but slightly larger. Then sand it to a wedge shape to fill the gap between the two wing panels. You'll have to cut a slot in it to allow the wing joiner to pass through. Temporally put the whole structure together and do a final sanding to get the three pieces to fit nicely. Once you got it all done then mix a batch of 45 minute epoxy and glue the whole works together and wipe the excess epoxy off with a paper towel which has been dampened with rubbing alcohol. Let it dry and then continue as the instructions dictate. If done neatly you'll won't be able to tell once you have the covering on.



Guess how I know how to do this