RE: building 4* 40 wing questions...
The 4* wing is supposed to have 2 degrees of dihedral on each panel. The "tool" provided with the kit is supposed to give you this. Each point along the length of the center rib, both sides, should lie flush with the jib. I found that it was pretty tricky to use this tool and get a straight rib. After you cut slots for the dihedral brace and before the upper spar is glued in place, the rib is pretty flimsy and its difficult to keep it straight. (On my first build I found some wide pretty wide gaps between the two center ribs when I joined the two halves.) I was thinking of making my own tool by squaring up a short section of 2x4 and then cutting a 2 degree face on my table saw. This would be a very wide version of the tool provided in the kit, but when held against the rib this would give support to the rib over its entire length.