I finished match-drilling the F-684 gussets over the weekend. This was a lot of work and noodling – probably more than most builders do – but I’m happy with the way these came out.

Once over the gusset hurdle, I fluted the F-902 bulkheads, opened up rudder cable holes to 5/8″ with a unibit, and riveted on some mystery nutplates. I think they’re for Adel clamps that secure fuel vent lines…

With the F-902s fitted, I started in on the F-7101 gear attach webs. These webs strengthen the area where main landing gear weldments would be attached…if I were building a nosedragger. But I’m not – no training wheels for me! The fit of these parts was surprisingly good. Some builders need to insert shims between the F-902 bulkheads and the -7101’s forward flange, but mine fit almost perfectly out of the box. Here’s everything clamped and ready for match-drilling…

F-7101 web being fitted

Next up is fitting the F-684 corner gussets. These 0.063″ plates reinforce lower longerons and bottom engine mount brackets. They turned out to be a pain in the derriere, at least for me. Because the gusset attaches to the longeron, firewall and bracket at different angles, a lot of finagling was required to make them fit properly. Here’s a crappy pic of the the first one trimmed and being fitted.

There was no way I could make 2D edge distance on the rear-most gusset holes, so I actually ended up discarding the precut parts and making replacements out of shop stock. Here are the finished gussets.

Big thanks go out to Bruce Swayze for help in braining out how to fit these parts. Cheers, Bruce…I owe you a beer!

Over the last several days got the F-717 lower longerons trimmed, twisted, marked and pilot-drilled to the lower firewall weldments. I always mark the places not to cut, lest I cut them!

The plans call for trimming the flange completely away, but I didn’t think it was worth the time since I’m not installing a training wheel up front and there will be no gear weldments in this area.

The plans call for trimming the flange completely away, but I didn’t think it was worth the time since I’m not installing a training wheel up front and there will be no gear weldments in this area. With the flanges trimmed I pilot-drilled #30 holes for the firewall attach bolts. I moved the holes inboard 1/32″ to give a little more edge distance in the steel; there’s still plenty of edge distance in the longeron.

Got the F-719 longerons trimmed, fitted and drilled over the last few days, including fabricating and fitting the clips the attach these longerons to the firewall. There’s actually a mistake on these clips, and I had to redo them. Can you spot the error.

Clamped in place for drilling…

…and clips are drilled. Rather than peel back the skin, I measured the correct distance on the firewall stiffener and marked/drilled the hole from the interior. Worked out fine.

Looks pretty good with the longerons in place…

Got the F-713 longerons marked, twisted, fitted, trimmed and drilled over the last few days, with no problems. I improvised a little to clamp the longerons in place for drilling.

Looks good…

Finished drilling the firewall to the F-770 side skins after measuring the firewall-to-skin distance several times. It’s difficult to get the required distance across the bottom of the fuse, but according to Vans it’s ok to move the bottom skin holes back a little. Sorry, no pictures of this area.

Even using recommended techniques for drilling holes in stainless (sharp bit, slow speed, lots of lube), I still had a couple of holes get egged out before I hit upon the idea of using my Brown Tool drill block to stablize the bit. Worked like a champ!

Clamped the longerons to the upper firewall weldments, then drilled them.

I had a question about edge distance on the weldment tab, but according to Vans and my Tech Counselor, edge distance in steel is less than that in aluminum. Didn’t know that…hmmm.

Working on fitting the firewall. Had to trim the longerons back about 1/32″ to get proper firewall-to-side skin distance. Also had to adjust longeron twist to nest them properly in the upper firewall weldments.

Longerons in place, clamped and trimmed ends.

Note from the future – turns out that the longeron shouldn’t be trimmed parallel with the firewall…at least on my kit. The lower leg of the longeron was interfering with the firewall weldment.

Also got the longeron-to-F704 shear ties fabricated and drilled.

Finished drilling the longerons today…lots ‘o drilling. Next up are trimming the longeron ends to accomodate the firewalll, and fabricating the shear ties that connect the longerons to the F-704 bulkhead.