Mid-fuselage bulkheads ready for primer

After a few hours of deburring parts, they're ready for primer!

I also fabricated doublers from .040 stock for the side channels in order to open more holes through them - the parts come with only two holes, and even though Van's says it's ok to open a third, I'll rest easier with this reinforced:

Doublers cut to size

Doublers match-drilled 

Fully-drilled doublers for having more holes passing conduits and air lines

The goal is to run 3 conduits through each side, pitot+AoA on the left and static air on the right.

I also, again per advice from VAF, countersunk the two holes on each of the forward center section bulkhead side channels that will need to de riveted double-flush:

Flange holes (top center) were countersunk for double-flush rivets

Next, I need to prime all these parts and start riveting.

Time lapse:

Total mid-fuselage bulkhead time: 33.3h

Forward fuselage ribs and bulkheads started

I've been going through the sections pretty quickly, it seems (though I've only been doing the fabrication parts, and leaving deburring/primer/riveting for later). Today I got to start Section 28 - Forward fuselage ribs, bulkheads and bottom skin (though I haven't done anything related to the skin yet).

This starts by assembling (mostly with bolts) the bulkhead assemblies, some final-drilling and then match-drilling through the control column mount for more bolts:

Forwad fuselage bulkhead sub-assembly

Both forwad fuselage bulkhead sub-assemblies

This section seems to be longer than most previous ones, so I'll likely have many more posts about it.

Time lapse:

Total forward fuselage ribs, bulkheads and bottom skin time: 4.5h

Firewall started

I started working on the firewall. Since I'm not yet sure about what engine I'll use or what I really need firewall-forward, I'm being conservative on which steps to undertake now.

The first step is assembling the main firewall parts and final-drilling them:

Main firewall parts clecoed and final-drilled

To prepare the firewall recess, the manual suggests dimpling certain holes with a rivet + female dimple die - I did just that, and sure enough, the dimple die was then firmly secured to the recess :p I had to drill out the rivet to actually remove it from the die:

The recess dimpled holes weren't supposed to be attached permanently to the dimple die

Finally, I match-drilled the forward fuselage rib and its parts, then attached them to the firewall bulkhead:

Fuselage ribs and related parts

Firewall with main fuselage ribs attached

Next I need to dimple all the holes on the firewall bulkhead and counter-sink the matching part holes. I also want to research stainless-steel rivets to use on the firewall, and I'm thinking of following the advice of many threads on VAF regarding fire protection, where they use steel foil with fiberflax on the forward side.

Time lapse:

Total firewall time: 9.1h

Mid-fuselage ribs progress

I did some more match-drilling, this time for the outboard and inboard seat ribs:

It was then time to flute the outboard seat ribs to match the holes on the bottom skin:

Finally, I deburred most rib holes from this section.

Time lapse:

Total mid-fuse ribs and bottom skins time: 16.3h

Wing wiring progress

We made some progress in wiring the wing, in preparation for riveting the outboard wing skins.

We added holes to the conduits, with bushings for the wires to come out:

Conduit hole with bushing

This was done with a heat gun with a circular tip, for simplicity - melting away the hole seems to be much more reliable in that it's unlikely that a cut will propagate and open up the conduit.

Heat gun for conduit holes

Opening holes in the conduits

Most holes were added near inspection panels (since that's where most equipment will be), except for the pitot heat controller box, which sits adjacent to one of those areas:

I was excited to pick a decent color scheme for the wiring, since so many colors are available, until I found out that most of the wires I'll end up running are shielded, and those are always white (with fixed colors for the inner conductors) :/

Given this, I decided to follow the Aveo colors for the wingtip wires (with one addition - using black/yellow for one of the returns). This is for the right wing, where the servos are - the left wing has antennas and thus gets the shielded equivalent.

We then started running wires:

Autopilot-to-trim-servo wires going through the conduit

For the pitot heat controller, I used 12AWG shielded cable (M27500-12TG2T14) - shielded so the magnetometer and NAV antenna can go on the wingtip without as much interference, and added connectors:

Pitot heat controller wired through conduit

I then ran the controller box wire to the bay where the pitot tube actually is, through the aft conduit Clickbond attachments:

Pitot heat wires going through Clickbond attachments

There'll be a lot more wiring to come, but most of that can be done with the wings closed - the main exception was the pitot heat, which will be much harder to access.

Time lapse:

Total wing ribs time: 16.3h

Mid-fuselage ribs started

I started section 26, Mid Fuselage Ribs and Bottom Skins.

The first steps were to break apart some parts, then put together the inboard seat ribs and match-drill/final-drill its holes:

Inboard seat rib subassembly with the flap actuator and seatbelt attachment brackets

Putting those together with the flap actuator bracket yields the first tunnel part:

Inboard seat rib subassembly

Flap actuator bracket between inboard seat ribs

I still need to further modify the flap actuator brackets to accomodate the newer flap motor (which has built-in position sensing), as those are supposed to be offset forward and up. I'll only actually have those motors in 4+ weeks when they ship it though, so that'll have to wait a bit.

That, along with the outboard seat ribs, got clecoed and match-drilled to the aft center section bulkhead assembly:

Aft center section bulkhead clecoed to inboard and outboard seat ribs

Next came the rear seat ribs (between the rear spar and the fuselage bulkhead subassemblies), which were all clecoed then match-drilled together, along with the rear seat belt attachments:

Rear seat ribs clecoed in place

Rear seat belt attachment points

Finally, I added and match-drilled the baggage ribs and step mounting brackets, and this now is starting to look like a fuselage:

Full aft assembly including baggage ribs and step mounting brackets

I now have a huge pile of parts (including the mid-fuselage bulkhead parts) to deburr and prime before I start riveting. I'll only match-drill the bottom skin once those are in their final position to avoid the difference in thickness from accumulating.

Time lapse:

Total mid-fuselage ribs and bottom skins rivets: 0
Total mid-fuselage ribs and bottom skins time: 11.4h

Mid-fuselage bulkhead fabrication almost done

After a quick trip to Germany, made a lot of progress on the mid-fuse bulkheads this weekend.

I started with the aft center bulkhead, which has bars at its ends for added structure:

Aft center bulkhead support bars

They also have two hat stiffeners, which I had to trim back to allow access to buck rivets next to it:

Trimmed hat stiffeners

I put the whole thing together, and did a lot of drilling:

Aft center bulkhead parts

Finally, this spar receives a plastic wear strip on top, which had to be cut to size, drilled then match-drilled to the spar:

Wear strip

I also did something similar for the rear spar bulkhead. This is the spar which attached to the rear of the wings, but I forgot to take pictures while it was still clecoed together:

Rear spar bulkhead parts

 Last there was the rearmost fuselage bulkhead, which was pretty simple and mostly gets done in later sections:

Fuselage bulkhead

Finally, I did a lot of deburring and all the countersinking that was left on these parts.

I also started thinking about how to run wires, pressure lines, oxygen lines, etc. between the forward and aft sections of the plane. I haven't decided on final routes yet, but it's clear that I need at least one more hole for conduits where the center spar is, so I added those to both bulkheads:

Third hole added to forward center section bulkheads

Third hole added to aft center section bulkheads

I plan to add a doubler to those bulkheads just for safety, so I'll enlarge them after the doubler is also in place.

Time lapse:

Total mid-fuselage bulkheads time: 18.9h

Mid-fuselage bulkheads started

The fuselage starts with the center bulkhead, doing lots of drilling:

Forward center section bulkhead parts match-drilled

then also drilling into the steel landing gear mounts:

Forward center section bulkheads with landing gear attachments

Drilled and bolted landing gear attachments

I had to significantly enlarge some holes for snap bushings where the rudder cables run  (it looks too close to the edge, but it's what Van's says to do...):

Snap bushing holes on center and side forward center bulkheads

and finally, a bunch of countersinking for flush rivets and screws:

Countersunk screw and nutplate rivet holes on the side bulkheads

Countersunk nutplate rivet holes on the mid seat rail supports

This was only the first part (the center section) and there are 3 more (the other half of the center section, the rear spar bulkhead and the fuselage bulkhead), so there's still a lot more drilling and countersinking to do.

Time lapse:

Total mid-fuselage bulkhead rivets: 0
Total mid-fuselage bulkhead time: 8.8h

Fuselage kit inventorying

I spent a good 7 hours between inventorying the fuselage kit and putting away all the hardware (which involved reorganizing the hardware bins). Luckily, for the inventorying, I had help from friends:

Rick and Jay helped inventory all the parts :)

Time lapse:

Bottom wing skin cracks

After sanding and priming the lap joint area on the inboard skin (which was a bit tricky given the skin was already riveted in place), I came back the next day to find this:

OMG a crack! :'(

After a few moments of utter panic as I saw a crack propagating, I contacted Van's, which assured me that the area is not structurally significant, and suggested two options:

• Filling the cracks with JBWeld: I was really surprised by this, as I thought the crack would continue to propagate anyway, but they swear it won't.
• Cutting off the corner: they say this should be fine, though less aesthetically pleasing due to the reduced thickness

I was way more comfortable with the second option, so I did that - it indeed doesn't look pretty, and I may still need a small doubler around that rivet hole to adjust the thickness, but I'm comfortable that the skin will stay in one piece now:

Cracked corner removed

As if that weren't enough, as I was dimpling the pitot mount screw holes on the other skin, some cracks showed up on the #8 dimples:

Cracks on the pitot mount screw hole dimples

so I had to file those down, which deforms the holes (but should be ok for screws):

Filed pitot mount screw holes

On the outside, it doesn't look perfect, but should not be even remotely visible:

Pitot mast holes on the bottom wing skin

In the meantime we also primed the other parts (such as the left bottom wing skin), and ultimately clecoed them in place and removed the blue pastic around the rivets, so they're ready to rivet and finally be done with the wings!

I'll make a separate post about the wing wiring and electrical planning.

Time lapse:

Total bottom wing skin rivets: 433
Total bottom wing skin time: 67.3h