HS-702 Front Spar Alignment to Skin

[john_r_graham]

I'm having an alignment / interference issue while trying to locate the horizontal stabilizer front spar properly to drill the holes in the spar inboard of the middle rib. Van's instructions at this point just basically say, make sure the HS-702 is held tight against the HS-405 main rib and then drill, baby, drill. When I initially tried to snug up the two parts, it looked like I might have a minimum edge distance issue on the spar, so I took off the skin and drew a centerline on the front spar flanges, making sure the centerline was collinear with the pre-punched holes outboard of the HS-708. When I put the skin back on and snugged up the front spar to the rib, here's what I saw:

The small blue mark showing on the end of the spar flange is the centerline. It's perfectly aligned at the first skin hole inboard of the HS-708 and smoothly diverges until it's just barely outside of the most inboard hole. It seems clear to me that the HS-405 is pushing the front spar out of position. Curiously, I'm only having this problem on the top of the spar; the bottom-of-spar centerline pulls in with almost no force and all holes align perfectly.

So what do you all think I should do? I'm thinking about carefully re-bending the top part of the front flange of the HS-405, effectively moving the bend backwards the requisite amount (which is about 1/16").

Any words of wisdom would be greatly appreciated.

- John

[bullojm1]

I'd re-bend the flange on the rib more aggressively. This will pull the spar further back and give you the alignment you are looking for.

[Wicked Stick]

I'd re-bend the flange on the rib more aggressively. This will pull the spar further back and give you the alignment you are looking for.

I agree, that would work, just be sure the rebend doesn't cause it to crack anywhere.

[john_r_graham]

Mike & Dave,

Thanks very much for the advice. I went ahead and did exactly that and it worked out okay.

- John