RE: Juno RC F-20
I suggest building the wing upside down. Although the instructions state otherwise, I prefer building it upside down. That way the top spar is flat against the building board. Make sure the wing building shim is installed correctly. I noticed when I was building mine that is made more sense to build the wind inverted, and install the shim as stated in the instructions. I had to think about it a bit, take measurements, and visualize it before I was satisfied. The current instructions are the originals, left over from DC. I'm not sure what the intent was, but it seems the shim would have to be installed just the opposite as written if using their building method. I built mine inverted and it all made sense to me.................I hope this helps.
Derek