As several people have asked about the construction details of the Wedge wing, I took a few photos while making the most recent one, #13. Those pictures and a brief description are presented here.
The first difficult step in building a geodesic wing structure is to layout the ribs at an angle. In my opinion, this requires the use of a CAD system but it might be achievable by hand using standard drafting techniques. Once the wing is drawn and the ribs laid out and cut, the assembly goes something like this.
Two pieces of 1/16" stock are used as shims under the ribs. One forms the trailing edge of the wing, and the other simply shims the spars to the correct height. This is all done over a set of line-drawings so that I can put things in the right place :-) The next critical step is to place the two end ribs onto the spars and TE stock, and align them both with the wing dimensions as well as vertically from the table. The blocks seen holding the ribs in place here are called "1-2-3" blocks because they measure exactly 1, 2, and 3 inches depending on the side chosen. They are extremely accurate (parallel w/in 0.0001", square w/in 0.00005" per 6") but this is, of course, totally unnecessary for modeling work. I already had them before starting to build toy planes. The final touchy part of this wing is the addition of the already-warped leading edge stock. It must be straight in two planes because all subsequent ribs will be aligned to it.
Once the wing is outside framed, it's time to add the first of the angled ribs. These must be aligned carefully to the leading edge stock, the trailing edge stock, and be held reasonably accurately at 90 degrees to the building table if a straight wing is desired. Note: The alignment to the spar is very much secondary to the LE and TE stock!
The place where the ribs cross also must be held fairly accurately. Note that the first set of angled ribs is goes in the middle of the wing- they could go anywhere but it's easier to align the center set to the rest of the wing in my opinion.
The rest of the ribs are now installed and glued into place. The last rib installed is the third straight one located about 1 1/4" to the right of the furthest left rib. These two ribs will support the center sheeting of the wing. Finally, the upper spars and top of the trailing edge stock is added.
At this point, believe it or not, the wing is picked up and turned around. This allows the first of the cap strips to be installed on both sides of the wing much more easily than reaching around to the front of the wing. Also the wing can be examined for straightness / squareness at this point. It weighs almost nothing and no doubt would not survive a drop to the floor but will tolerate being moved around if one is careful.
I won't bore everyone with the details of adding the cap strips- they're quite conventional and not difficult to do. The center ribs are left bare, as well as the first inboard set of angled ribs so that center sheeting can be added after the wing halves are joined. Of course there are two of these halves to make one wing and they are built over the same drawing in the identical fashion.
This view shows how the leading edge stock is used to align the ribs. Each rib has a small notch cut into it on the centerline during construction. The L.E. stock has a straight line drawn right down the center. The notches of the ribs are aligned with this line- done carefully, I have not had a wing deviate more than about 0.015" using this method. Alignment means something later on besides just having a straight wing too- the cap strips have to be line-sanded and as they are only 1/16" thick stock, any more than a very slight deviation will cause some to be as thin as paper.
Once we have two straight wing halves, they need to be joined. I do this by simply holding them together in my hands, sighting them for straightness, and CA gluing the spars, T.E. and L.E. stock together. After verifying that the wing is truly straight, it's then mounted back on the building table for the center sheeting and the final cap strips. This photo shows the first two bays being braced by shear webs and the spar bracing just behind the spars. Most of the wing is cap-stripped at this point too. The center sheeting can be seen in the bottom-right of this photo.
The center sheeting is added to the top using CA glue. When one side is done, the wing is flipped over and the other side is also center-sheeted. All materials used in this wing are either 1/4" square balsa or 1/16" balsa sheeting with the single exception of the leading edge stock, which is 3/32" thick.
Finally, once the cap stripping is complete right through the center section, and the rest of the plane is wrapped around it, it looks something like this....
