This was a busy week around the house but I still managed to keep some momentum on the airplane. The next task on the list was fabricating and installing the hinges that attach both seat backs to the cabin floor.

There’s not much to installing these hinges. Trimming the hinge material is trivial, and the only gotcha is to make sure the hinge spacing from the inboard seat floor edge is actually measured from the edge, and not from the center of the nutplate holes as the plans trick you into believing if you’re not careful.

Although I didn’t take any pictures of the process, I laid out and drilled rivet holes on one hinge plate and used it as a template to match-drill the other hinges. It was easy then to clamp the hinges onto the floor and match-drill first to #40, and then final-drill to #30 for the rivets.

Only one or two of the rivets can be squeezed, and I don’t have a C-frame dimpler/riveter, so I just laid out my backrivet plate on the workbench and used it as a bucking bar as I drove the rivets from the top. Worked pretty good. The hinge material is a little on the soft side, which causes them to distort a little when riveted but I can still get a hinge pin in.

Here’s the copilot side ready to be blind-riveted to the seat ribs. The other side looks pretty much the same, except for one problem.

Turns out that one of the pilot’s seatbelt anchors somehow got tweaked out of alignment, and I wasn’t too keen on bashing it back into alignment with a hammer or pliers. This had to be fixed before I can blind-rivet the seat floor, which means drilling out a lot of blind rivets and hard-to-reach solid rivets…merde!

So, I spent my entire shop time on Sunday drilling out all the rivets that attach the left baggage floor, so I could yank it out for access to the anchor bolt. It took a lot of time to *very* carefully remove all the solid-riveted nutplates, because many of them were in corners or in hard-to-reach areas.

With the solid rivets and nutplates removed, I used an ATS Blind Rivet Removal Tool to drill out all the blind rivets – this gadget worked like a champ, unlike other ATS-made tools I’ve owned. The tool’s drill bit is surrounded by a spring-loaded serrated collar that applies pressure to the rivet head when the tool is pressed onto it, keeping the rivet from spinning in the hole as the drill bit does its thing. Driving out the steel mandrel from the blind rivet is essential, since it can cause the drill bit to wander as it punches through the rivet.

After cleaning up all the rivet carcasses, mandrels and shavings, I reinstalled and retorqued the offending seat belt bracket and declared success for the day. It was a lot of work, but worth it to get the job done right.

Thanks to the leadership of Our Elected Officials™, I won’t be working Fridays for the rest of the fiscal year (that’s the end of September for all you non-government folks) and today was the first day off. They call it a furlough, but I like to think of it as an unpaid holiday – helps me to not focus on the money we’re diverting from Whitney’s tuition to pay our bills.

But an extra day off every week will be great for progress on the RV, so there is a bit of a bright side to government incompetence.

First up today was fitting the baggage compartment tunnel cover.  The fit on this part was, shall we say, crappy…I had to apply some kinetic manipulation (i.e., a block of wood and a hammer) to get the rear flange to fit correctly.

The fit still isn’t great, but I was able to get screws in all the mounting holes without enlarging them.  Good enough for government work…if I had been working for the government yesterday.

With the baggage tunnel cover in place, I moved on to the baggage area flap covers which isolate the flap actuator arms from the rest of the baggage compartment.  These were a piece of cake…drill holes to final size, debur, dimple the nutplate rivet holes, and attach the nutplates.

That’s the end of the baggage compartment work, it’s on to the seats.

I’ve had the baggage compartment bulkhead walls sitting around for several years, it was nice to finally break them out for installation.  Fitting the bottom bulkhead wall is easy, there are prepunched holes that match the platenuts previously installed on the baggage floor.

Once the wall bottom was attached with screws, I worked my way up from the bottom, match-drilling the bulkheads through prepunched holes on the sides.

The top of the wall requires a little more work.  The upper corners must be trimmed on an 8.5 inch radius, so I borrowed a tip from Mike Bullock and cut a template from stiff paper to lay out the cut line.  It was a little tricky tracing and cutting through the wall’s deep corrugations, but with a little filing and trimming they look fine.

With the corners radiused, I laid out and drilled the remaining wall-to-bulkhead screw holes and match-drilled the wall to the bulkhead.  Nothing too tricky here.

For some reason, it was pretty motivational to see this bulkhead wall in place…makes the fuselage seem more “finished.”

I broke out the #8 nutplate jig, drilled the bulkhead for nutplates, dimpled both the nutplates and mounting holes, and installed the nutplates.

The shoulder harness restraint cables penetrate the bulkhead well, so I laid out and cut slots for the cables.  There are a couple of pieces of UHMW plastic that get fitted around these slots to provide a wear surface, so I trimmed and drilled them to the upper and lower walls.

I’m saving the wear block final installation until the walls are painted.  I’ll probably do that sooner than later, since we want to see how our interior color choice (JetFlex WR “Pepperdust”) looks.  I can paint the wall parts, and if we don’t like the color, I can strip ’em down and find another color.

There’s not much to report this week.  My wife spent two long sessions in the ER dealing with kidney stones, and everything else took a back seat to helping her.  According to the ER doc, kidney stones cause the worst pain a person can experience and after seeing how much pain Ellen was in, I believe him.

Things were a bit more stable over the weekend.  I had some time yesterday to deburr all the little gussets and parts I had previously drilled, and after a very nice Mother’s Day lunch this morning with Ellen at our favorite airport restaurant – Nancy’s Airfield Cafe at 6B6/Stow MA airport – I primed all the parts that needed it.

The primer takes a day or so to completely cure, so they’ll be ready for riveting after work tomorrow.  I still have some deburring to do on the longerons, however, and I’ll need a couple of extra hands for riveting some of these parts.

I also riveted a mounting ring on the Garmin magnetometer mounting bracket mentioned in the last post.  The alignment pins and screw holes ensure that the magnetometer is correctly oriented to the fuselage, and it’s a lot easier to rivet this now while the bracket isn’t attached to the rear deck.

“There’s nothing to it but to do it”…that’s what my good friend Captain John says whenever he’s confronted with a seemingly difficult task on his RV-7 project.  I don’t have any really difficult tasks brewing right now, but there are a few things in the last week that required a little braining out and that’s when I tend to overanalyze things and make them more difficult than they really are.  Today’s post is an example.

There are a couple of longeron-to-firewall gussets on the forward fuse that are actually leftover parts from the RV-6.  Because of that, they don’t fit precisely on the RV-7 and require some tweaking to fit.

The F-695 gussets tie together the longerons, upper firewall weldments and firewall stiffener, so they have to fit against three surfaces *and* also maintain proper 2D edge distance on the firewall and longeron rivets.  As delivered the gusset doesn’t fit flush against the firewall, which would compromise edge distance on the forward rivets in the firewall stiffener.  So after consulting with Vans I removed a very small amount of the gusset’s forward edge to make it fit flush.

I also had to put a slight upward bend in the forward edge (the bottom edge in this picture) to get it to lay flush on the firewall stiffener.  I also laid out the rivet holes not quite per the plans; because the gusset is a few 32nds shorter, the fore-aft rivet spacing had to be adjusted a little.

I pilot-drilled the holes to #40, clamped the gussets in place, then enlarged the holes to #30.

And they’re done, nothing left but to debur, prime and rivet.   See what I mean about the overanalyzing comment?

The only downside to all this effort is that I made a big freakin’ mess in the forward floor…

I’ve pretty much committed to installing Garmin’s G3X EFIS system as my primary flight instrumentation.  Trying to get ahead of the avionics installation game, I bought a mounting bracket for the G3X magnetometer – basically an electronic compass – so I could install the bracket on the aft deck before riveting it in place.  Garmin makes this bracket specifically for the RV-7/9 and has excellent instructions for aligning and installing it.

The bracket is easy to install – only six rivets – but it’s important to get it aligned closely with the aircraft centerline, otherwise the compass will have a built-in heading error.  So I laid out a very precise centerline on the aft deck, clamped the mounting bracket in place against the forward flange, and match-drilled it…very easy.

There’s nothing left to do but debur, prime and rivet all the bits-and-pieces parts I’ve fitted over the last couple of weeks.  I hope the Boston weather cooperates with priming…