Forward fuselage ribs and bulkheads progress, Andair fuel valve bracket

I made some more progress in this section. I started by trimming the control column mounts, which my new band saw blade made a trivial task:

Trimmed control column mounts
I then clecoed and match-drilled the forward bottom skin ribs, which go underneath the pilot/copilot floor:

Forward bottom skin and ribs
I attached the firewall parts to it and final-drilled their holes:

Firewall and tunnel attached to forward bottom skin and ribs
then finally added the floor panels:

Floor panels mounted to bottom skin/ribs/firewall

Floor planels mounted to bottom skin/ribs/firewall
I got a kit for a tunnel side access opening - its holes didn't line up with the pre-punched ones, so per their recommendation I shifted the whole thing forward and drilled new ones. This also required trimming off the corner of the doubler:

Tunnel access panel doubler match-drilled into place
A few days later, I received my Andair fuel valve:

Andair duplex fuel valve (extender not shown)
The small challenge with those is that they don't fit into the Van's-provided bracket, so I had to fabricate a new one - slightly annoying since the flanges are at an angle (the tunnel does not have parallel walls). I'll leave somewhat more detailed steps here, in case it's ever useful to anyone.

I started by laying out the existing one onto a new sheet, and then mirrored it to make room for all the holes:

Fuel valve bracket sketched on aluminum sheet, based on original part
I also realized the holes are not symmetrical, so it'd be tricky to transfer them onto the sheet, but luckily the face plate has the exact same alignment, so I used that:

Fuel valve face plate holes align with the valve holes exactly

Transferred holes from fuel valve face plate to sheet layout
I drilled the holes, including the center one with a unibit to 1-1/4", and adjusted slightly to make sure the valve fit:

Valve temporarily attached to new bracket web
This would make the web for a new bracket, and I also cut two 2" x 2.5" rectangles for the flanges. I bent them using a wood block and rubber mallet, then transferred the holes from the original bracket onto them, making them exactly .064" lower (so that the web, coming atop the flanges, would be at the same height):

Transferring holes from original bracket to new bracket flanges

Side view of hole alignment between old and new bracket parts
I picked two points at reasonable edge distances on the "webs" of both flanges, and drilled holes for nutplates there:

Nutplate holes on new fuel valve bracket flange parts
With those loose parts, I clecoed the flanges to the tunnel, laid the web on top, and then clecoed the original part just above them, to get the same spacing:

Fuel valve and web part laying onto flange parts, with original bracket above it
I started by visually aligning the center shaft with the original bracket's hole, and clamped the web to the flanges:

Alignment of Andair fuel valve center shaft with center hole of the original bracket
I verified by putting the tunnel cover on and checking that the center was aligned (minus parallax) with the original hole meant for the valve:

Tunnel cover on top of tunnel, for valve alignment

Valve shaft alignment through the cover hole
With that, I went on to match-drill the nutplate screw holes onto the web:

Match-drilled web and flanges for the new valve bracket, seen from the top

Match-drilled web and flanges for the new valve bracket, seen from the bottom
I checked that it overall matches the original part in size and flange angles:

New valve bracket, with original bracket on top to check for matching angles and distances
Then finally, I countersunk the nutplate holes, deburred and clecoed the whole part back in the tunnel:

Final-drilled, deburred and countersunk parts for new valve bracket

New valve bracket mounted into place
Finally, I attached the forward center section bulkhead to the forward ribs and match-drilled them:

Center section bulkhead clecoed to forward ribs and skin
Next I'll start disassembling and deburring all these parts, then priming and riveting them.

Time lapse:



Total forward-fuselage ribs and bulkheads rivets: 0
Total forward-fuselage ribs and bulkheads time: 23.6h

Mid-fuselage ribs riveting

I started riveting the mid-fuselage ribs that I had already primed:

Forward mid-fuselage ribs riveted to aft center section bulkhead
I specifically avoided riveting the two inboard ribs on the aft end, so that I can insert the heat tee and flap motor bracket later, when they're primed.

Most rivets were trivial, though some are later hidden behind other parts:

Flush rivets hidden behind other parts

Rear bulkhead side channel riveted to rear spar
I clecoed the other ribs to see what I'll need to do for passing the conduits to the tailcone:

Simulated conduit runs through the baggage area ribs
With that, I concluded that I also needed to use the lower hole (that goes below the step mountain bracket), so I enlarged those to 3/4":

Enlarged fuselage bulkhead hole for a conduit
For the flap motor, I'm using a non-standard motor which has a built-in position sensor and automatically stops at the end of the travel, so I first mounted the standard motor and found the right angles for the extremes:

Original flap motor at the retracted position

Fully-extended flap position marking
I then mounted the new motor and found a position it can sit in which will give roughly the same two extremes:

New flap motor matching the fully-extended flap angle
Next I have a lot of deburring to do so I can prime and rivet the rest of the ribs.

Time lapse:


Total mid-fuselage ribs rivets: 196
Total mid-fuselage ribs time: 40.5h

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