RE: F-4C Phantom - Pavel Bosak
OK. Got started on the wing. This one is different from anything I've ever built, in that the spars are swept back, the forward one at 68 degrees, and the aft one at 75 degrees. This can be seen in pic 1, which shows the drawing. Obviously, this means the notches in the ribs and spars must be cut at corresponding angles or the wing will come out straight, instead of with a swept leading edge. Pavel mentions nothing about this in the instructions, and rightly so, as his philosophy is that if you're far enough along to be building a semi scale Phantom from drawings, you should know this kind of thing already. (I should have, but that didn't stop me from making forward spars and four ribs that are now in the scrap bin.)
Since my scroll saw table tilt only goes up to 45 degrees, I had to take the complement (correct term?) of each angle (90 minus the angle). So, all the forward slots got cut at 32 degrees, and the aft ones at 15. I set the table angle with a protractor, as the handy little gauge installed on the saw is off by about 1.5 degrees. Pic 2 shows the forward, right spar being notched. Note that the term "RFC" is on the right end of it (in the picture), along with an arrow. I had to mark everything this way after I had figured out how the cuts had to be done. It means "Right For Cut", or, put this end to the right, dummy, when cutting. If I hadn't done this, I'm sure I would have gotten confused and ended up with a big mixture of angles, none of them correct.
Pic 3 shows the same process for rib W1, right side (bottom forward notch), and pic 4 the same rib, but the top, forward notch, all cut at 32 degrees. To do the top notch, it's necessary to turn the blade around backwards in the saw.
Pics 5 and 6 show the same rib, aft notches, which are cut at 15 degrees.
Pics 7 and 8 are the finished product, with rib W-1 fitted to the forward and aft balsa spars, and the 1/8x3/8 spruce cap spars shown at the forward locations only.
This process only took three days to figure out. I kept getting turned inside out and tied up in knots. If you're not confused now, you never will be. If someone replies with a really simple way to do this, I'm going to go fall on my sword.
Haven't quite figured out how to stick all this together. There's no flat surface on the ribs, so it can't be done on a building board. I'm thinking about using 12 small clamps to clamp all the "junctions" (where spars and ribs cross) together, then make sure I've got the TEs and LEs aligned, then sort of hold it over the plans to make sure all the ribs are pointing forward while the spars are aligned. Then maybe just tack glue all the balsa parts together with thin CA, enough so it'll hold it's shape when I remove the clamps and spruce spars. Finally, epoxy the spruce spars top and bottom, forward and aft and use the clamps again.