Only combat plane I ever folded the wings on (without outside help of course) was Riley Wooten's Vampire, (hmmmm is that the right name?), his early foamie with tagboard covering and no spar, or any longitudinal elements for that matter. It was a 2-piece wing, I think it had some splice pieces at LE and TE, mostly for alignment, and about a 6" "spar" in the center to anchor the bellcrank. A little bitty 1/2" wide strip of tagboard over the center seam was supposed to hold it together. It flew great until it folded--and it always folded. Hey it was early early foam (mid sixties?), what did we know?