Wing Attach

Notes from schu:

1. Level the fuse side to side and fore/aft.

2. Setup a level by taping or zip-tying little pieces of tubing on the level 32" apart from each other. This allows the level to touch on a small surface, right on the front and rear spar, ignoring the shape of the wing.

3. Put the wings on the airplane and pin the rear mount. I machined a pin that was 1/4 necked down to 3/16 so I could pin the rear mount exactly in the center.

4. Make some shims to take up the space between the wing and mount. You want this as tight as possible. I stacked aluminum scrap.

5. Look at the where the front wing hole lands in relation to the fuse mount and start measuring. Overall incidence is not important because you could only change it .1* anyway, and it's not worth the risk to have the wing hole very offset from the fuse.

6. Now look at dihedral and sweep, get those where you want them.

7. Once you confirm you have both wings where you want them and the wing holes are inside of the larger fuse holes (or very close) clamp both wings to the fuse. You can try to pinch the mount but that was hard to do, I ended up putting one clamp on the spar and clamping that clamp to the fuse. Make sure nothing moves, incidence is good, dihedral is good, and sweep is good.

8. On one wing take a needle file and file out the wing hole until it matches the fuse hole.

9. Double check measurements, if still good, run a 1/4 drill through the whole thing using the drill jig to make sure it's straight.

10. Check everything again. Drill to 9/32. This should make a very nice/clean hole.

11. Check everything again. Drill to 23/64.

12. Now ream to 3/8.

13. Repeat 8-12 for the front of the other wing.

14. Now you have the front done, but you still have 2 more chances to fix mistakes. Repeat 8-12 for the rear of the first wing, using 9/32 then 19/64, then ream to 5/16.

15. Now one wing is fixed, but you still have 1 more chance to fix mistakes. Repeat 8-12 for the last hole.

16. Take a lift strut and square off the end and deburr. Cut the strut so that it is 3" shorter than the center to center measurement between the mounting holes giving you 1.5 from the strut edge to the mounting hole on both sides. 

17. Put the strut into a vice with soft jaws and make sure it's level. Clamp such that the vice jaws only contact the last 4.5" of the strut. Make a parallel shim that goes inside the strut to crimp to. I found around 25% springback. I used round tubing I machined on my lathe as shims/spacers because it's easy to make it dead parallel, and easy to trim of 1/8" while retaining parallel. Crimp the strut until the fitting just slips inside.

18. Clamp fuse lift strut fitting on the top of the strut giving 1.5" between the center of the mount and the end of the strut. About 11/32 between the end of the strut and the first hole. Make sure the mount is dead center of the inside flats. Using a 1/4 center point drill drill through the mount into the strut enough that you have a nice starter hole on the top of the strut. Now drill out the rest using a 15/64 bit. The idea is that you use the 1/4 bit as a center drill, but then make a slightly smaller hole and keep the drill off of the sides of the fitting. Now run a 1/4 reamer through it. You end up with a very nice reamed to size hole and you didn't harm the fitting, which keeps everything straight. Drill all 4 holes.

19. Mount the fitting to the top of the strut with an4 bolts.

20. Make two 1/4 pins that have sharp points that are slightly longer than 1.5, put them in the wing side fitting that is bolted to the wing, clamp the strut onto the bottom of the fitting. Make sure the dihedral is perfect, and that the fitting is in the center of the strut, then tap on the pins to make... Read more 14:24

The manual is far too wordy and talks about measuring and drilling stuff on the bench which in my opinion gives you too much room to screw up. I developed my own process which drills one thing at a time in such a way where you have 4 chances to fix stuff. I also developed a process to drill the struts in such a way where you can get everything straight and matched drilled, but you still drill undersized so that every whole is reamed to size.

All 20 holes are perfectly straight, smooth, round, and have maybe .003 clearance to the bolt.