Sounds like your on the right track. I would set some ply plates into the foam for the gear to mount on though. Maybe 1/4 thick by 1/2 wide and put it under the sheeting. When you glue it in, use epoxy with cotton flox to glue it in instead of micro baloons. Either will work, but flox is way stronger. You can get it at aircraft spruce. In building full scale, I was taught never to use micro balloons in epoxy where you need streangth. It is a good filler. You will probably get lots of different opinions on this, but I figure Burt Rutan knows what he is talking about. Anything you use will be stronger than the foam. Try to make the cuts as clean as you can so you don't have to do a lot of fill when you glue them in. I wouldn't use spars in a foam wing either.


Sounds like you were trying to use glass for streangth on the gear on the build up wing? Just for what it is worth, I streangthen gear in a build up wing with triangle stock. I wouldn't use glass there. I know it can be done, but you can get more surface to glue to with triangle stock and stiffen the ribs with 1/8 inch ply. You won't add a lot of wieght and you will get really good gear. Have a blast.