Are there any print out planes for this new wing? I am having a similar problem with my viggen. the wings folded almost completely in and caused some bizarre flight characteristics. Luckily I was able to bring her back home, but it was a challenge. Thoughts on adding some spars that are flush with the angle on the fuselage made out of simple bbq skewers?
I have built a few Viggens of late and so far none have had wing sag or fold problems. The first Viggen I saw in flight was a genuine FT kit using the FTFB and it was somewhat flexible from the start. (The owner had flown it without any sealing or the like and it was flexible in the wings from the get go! He eventually went the KFM route and whilst the wing was stronger the performance was effected negatively.
With my latest builds I actually use a length of CF tube the same diameter as the FB is thick. The single CF tube length, (1 metre), is cut into two pieces and The two pieces are fitted into the FB by cutting channels for the CF in the wing UPPER surface firstly around 1.5 inches in front of the elevon hinge line and The smaller piece is fitted in another channel cut in the wing upper surface around 3 inches from the most forward part of the wing, (the exact positions are not that important but do not have the CF reach to the wing edge as it reduces the resilience and ability to repair in the case of a crash. I use epoxy to fit the CF into the FB channels. Try to keep it neat and wipe off any excess from the epoxy before it sets.
Once the CF tubes are fitted and the glue is set, seal the exposed FB wing edges with glue and then minwax and seal the wing. Paint the heck out of it!! The paint actually makes the FB more rigid but only if the FB is properly sealed first. The wing should/will fit onto the fuselage exactly the same as before prior to sealing and painting of course.
If you crash the wing edges will be damaged but you can cut out severely damaged pieces and graft in patches which you seal and paint to match. So far I have not seen one with CF reinforcing actually crash beyond repair even though there have been treeings, and total OOC landings.
All of this does add a bit of weight but with the larger motor or EDF setup the bird still performs very well!
I hope my experience helps you getting your bird back in the air!
have fun!