Horiz stab spar cap gaps

I'm a first-time builder looking for advice. Some of my concerns may be misplaced.

When installing the spar caps on the horiz stab, I noticed the bend angle of the spar caps doesn't match the bend angle of the spar flanges, thus the spar cap doesn't nest properly in the spar. The first pic shows the spar cap clecoed to the flange resulting in a gap between the spar cap and spar web. A .016 feeler gauge goes into the gap easily. Clecoes do not close the gap, and I wonder if riveting will.

I wouldn't mention this, but the instructions make a point that the spar caps must firmly contact the spar along their entire length for full structural strength (make sure all holes are deburred, chips cleaned out, etc.)

The second pic shows a straight-edge held against the spar flange next to one of the ribs, indicating that the spar flange angle could be bent inward a bit to line up with the rib flanges.

Should I just "build on" or try to improve the fit before riveting?




jake14
#140158

Jake, I started with the wings and have not assembled these parts yet, but I would definitely not use the rib flanges to try and judge how straight the spar and spar caps are, or are not. Looks like the feeler gauge you have inserted is .016". This small of a gap should close up with Cleo's in every hole. You may also want to try and hand straighten these parts if they appear to be bowed. You could also use some clamps to close the parts and set the rivets.

gap

You could try draw clecos or clamps to close the gap. If after riveting you can get any feeler gauge to touch the rivet shank it is cause for rejection.

Thanks, good input. I just opened up the angle on the spar caps a small amount. They look good now.