Help Me Fix a Boo-Boo (Sonex Forward Fuselage)

[Andy Walker]

Hey all...

I've been diligently working on the forward fuselage side panels, and all has gone great...until today. I made what I think is a minor mistake, and I'm trying to figure out the best way to remedy it. On the side panels, almost all the major angle pieces are supposed to have 1/16" gaps between them and adjacent parts. I *think* this is so that under normal fuselage flexing, the parts do not grind against one another.

All of my parts have these gaps, but today I screwed up the right side seatbelt attach angle. I got it all squared up in the right place, then drilled it in place, and the bottom edge was right up against the lower longeron, instead of 1/16" off of it. Basically the top has a double gap and the bottom has none. Here's a pic:



So, my idea is to take some metal away from the bottom edge of the seatbelt attach angle, thus creating a gap. The gussets that attach to the angle and longeron (below) and the horizontal angle (above), as well as the rest of the seatbelt attach hardware may have to be shifted slightly, but I can't image any real loss of strength or other problem. I'm trying to avoid having to reposition and re-rivet, as that puts extra holes in my skin (not to mention the attach angle).

Does anybody see any major problems with my plan, or have a better idea? Help me Obi-Wan Kenobi, you're my only hope...

[142YX]

WOW we must be neck and neck.. i just worked on this very assembly today as well!

Unless you are trying to make a showplane.. shave some metal off of it and move on, thats my advice. I screwed up positioned the member right above this one an 1/8th too low on the right side, had to make a similar modification (to the top of the same bracket). These metal bits only comunicate load between each other in shear.. and only at the location of the fasteners. So my rule of thumb is unless it affects a revit/bolt position, makes some other assembly impossible, or is so ugly that i can never live with myself.. i move on with my misstakes.

[Andy Walker]

WOW we must be neck and neck.. i just worked on this very assembly today as well!

Unless you are trying to make a showplane.. shave some metal off of it and move on, thats my advice. I screwed up positioned the member right above this one an 1/8th too low on the right side, had to make a similar modification (to the top of the same bracket). These metal bits only comunicate load between each other in shear.. and only at the location of the fasteners. So my rule of thumb is unless it affects a revit/bolt position, makes some other assembly impossible, or is so ugly that i can never live with myself.. i move on with my misstakes.

Sounds like we're on the same page with build philosophy! :D

You may actually be quite a bit ahead of my on building, I did things a little backward and am doing the fuselage before the wings. If you are building as most do, your wings are probably done. If not, maybe we can arrange a two ship first flight. :mrgreen:

[142YX]

Nope.. i have the wing spar and control surfaces done.. but i stopped building the wing to complete the fuselage. My thinking is that it will be more motivating to finnish once i have something that i can sit in and make airplane noises with.

[N111YX]

Andy, take a few thousadths off the seatbelt angle and carry on. You could probably take 1/4 inch off and still have a valid structure...and a showplane...:)

[Andy Walker]

Andy, take a few thousadths off the seatbelt angle and carry on. You could probably take 1/4 inch off and still have a valid structure...and a showplane...:)

Hehe, I guess the judges won't really be able to see it... ;)