The best fix I have found- get the quick set instant gorilla glue- it is white when it cures. Lightly coat both pieces well to get 100% coverage. Then fit the wing back together. Cover the seam with clear packaging tape- then douse with water- enough will seep around the tape to kick off the gorilla glue. The tape will keep the glue from making nasty bubbles. After this has set up use some flat carbon fiber sticks- probably some 5-6in pieces of the 1/4" wide stuff, Cut some thin slices the bottom of the wing and span the break in 2-3 places with the carbon. Glue it in with gorilla glue with the same tape procedure. It will be stronger than new and with some practice you can hardly see the repair. I have glued numerous foam planes back together this way. It is much more durable than a CA repair.