RE: Mojo 40 Build Thread
I ran into my first problem today. When measuring for the LE sheeting, I noticed one wing was 1/8" long than the other! It took a while to figure out why. The problem is that the drawing shows all ribs as 1/16" thick. Mine were 3/32". With two pieces used for the root rib, this means the root rib is 1/16" thicker than shown on the drawing. When I spotted the root rib, I put the right had side flush to the right hand side of the line for the rib. I did not notice this meant that the left side was actually 1/16" over. Effectively, I shifted the center line to the left by 1/16". Then, the usual slop added another 1/16" but unfortunately it added to the long side for a total of 1/8" of extra length. I ended up pulling the wing up off the board and re-setting the center line. I then had to cut out the last two ribs from the right side and re-spot and glue. It took a couple of hours to carefully cut the ribs and get them back again. Almost felt like a crash re-build! I spotted with the right hand outboard rib on the drawing location and this left me still with about 1/16" extra on the right side and I figure that is within the normal slop.
Having fixed the errors from yesturday, I proceeded to make two more today. First, when cutting the taper on the LE sheeting, I measured the 5/8" inset but did it on the 36" length. I had forgotten to cut to the required length first. I noticed the mistake on the first piece and could re-cut it since the taper was steeper when doing it correctly. However, this meant I "lost" some of the sheeting for the center sheeting.
The next mistake was attaching the LE sheeting. I glued it to the main spar. Luckily, I noticed this right away and pulled it up and re-glued. In this mistake, TBII helped because I had lots of time to pull it up and re-mount. CA would have been bad with this mistake.
Anyway, I hope I have all the goofs out of me.
Photo #2 shows the center sheeting butt joining. Becuase of the mistake on the sheeting, three pieces were only 10.5" long versus normal 12". Since instructions mention, and measuring confirmed, you need about 12.5" of length, I used some of my shop 3" stock to get me back to the right length. Photo #2 you can see the "short" mistake-piece of sheeting and the extra new piece (whiter color on the bottom).