I started working on the flap system, which is mostly the torque tubes and crank that connect the motor to the wings.
This starts by setting the torque tubes and horns in very specific angles/distances and match-drilling for bolts:
Flap horn, torque tube and crank in position for drilling
Drilled and bolted flap torque tube, horn and crank
Both torque tubes and horns drilled and bolted to the crank
These tubes are mounted into delrin blocks for alignment, so those had to be trimmed:
Delrin bushing blocks marked for trimming
Trimmed torque tube bushings
After priming the tubes, we installed them, which was actually quite a bit more work than expected given how tightly everything fits together (and the layer of primer doesn't help there):
Installed flap torque tubes, bushings and crank
Torque tube to horn attachment bolts, in a tight area
Horn, torque tubes, bushing and crank
With this, the only step left in section 40 is actually installing the motor, but for that I need to finish figuring out the bracket for the PHA motor (which also involves completing the last few steps of section 26)
Time lapse:
Total flap system rivets: 0 Total flap system time: 14.0h
I've been working on the baggage door slowly, whenever there's nothing else to work on.
This section is mostly straight forward - cleco everything together and final-drill:
Main door parts clecoed together and final-drilled
then the tricky part, which is making the hinge and drilling it on both sides such that the door is actually flush to the rest of the skin:
Marking the hinge holes for the door side
Marked hinge for drilling
I also used the common deviation from plans that involves cutting half the hinge eyes so that pins can be inserted from the center, allowing the whole hinge to be closer to flush with the skins:
Door hinge with 3 half eyes removed for pin insertion
Making the door hinge almost flush with the skin
Finally, the recommended method to drill the other half of the hinge to the fuselage involves modifying clecos so they fit inbetween the halves:
Specially modified clecos for the door hinge
then centering the door and match-drilling from the inside:
Door centered in place and held by tape
which, of course, went very wrong:
Accidental double hole when drilling the fuselage side of the door hinge :/
so I did the whole hinge over from the start, just reusing the door side holes and match-drilling the door to the hinge rather than the other way around. This time I was a lot more patient and careful in drilling the hinge frame into the hinge, so it went fine, and I countersunk the hinge:
Match-drilled and countersunk door hinge
The next steps are just deburring, primer and riveting.
I was also considering adding a baggage door sensor (microswitch or similar), but given how hard that'll be, it's probably not worth it.
I continued working on the access covers, first by getting the seat back brace closeout to actually go in and be final-drilled:
Seat back brace closeout in place for final drilling
After I primed some parts, I riveted the floor pans:
Floor pans with nutplates, ready to be installed
Installed rear seat right floor pan
Installed rear seat left floor pan
For the outboard row of rivets, where you have to buck in a tight area, it quickly became clear that solid rivets were not going to work very well:
Bad, removed rivets from trying to use solid rivets on the outboard row of the floor pan
so (after finding something from Van's saying that they're not load bearing) we switched to blind rivets and got that done quickly as well:
Blind rivets used on the outboard rows of the floor pans
Next was match-drilling the rear seat cover panel to the longeron, and installing nutplates there:
Machine-countersunk nutplate attachment holes on longeron
Nutplates installed underneath longeron
and finally, I realized I should have final-drilled and machine-countersunk the top flange of the forward fuselage bulkhead long before, so I did it now:
Machine-countersunk top bulkhead flange
Time lapse:
Total access cover and floor panel rivets: 286 Total access cover and floor panel time: 19.3h
While waiting on the weather to prime some parts, I started section 42, the rear seat backs. This starts by fabricating some angles:
Rear seat back angles
Two of those need to be rounded at the vertex to nest in the top part of the seat backs:
Rear seat back top angles, one of them rounded at the vertex
The way I found to do this with some precision over the length of the angle was to make a 45-degree chamfer first until the width of the material was the same on the vertex as on the flanges, and measuring to ensure that the width of the chamfered area was the same throughout the angle, before finally rounding it:
One rounded (right) and one chamfered (left) rear seat back top angles
Forward side of the rear seat back, match-drilled to the angles and hinge half
Back side of the rear seat back, match-drilled to the angles and hinge half
As a minor detail - Van's tells you to cut the hinge pins in half, at 8" - don't :) The removed hinge eyes are not exactly centered, so I found that it's much better to cut them at the center of the removed eyes:
Hinge pins cut in half (top) and at the center of the removed eyes (bottom)
Some of the parts had some excess length which I'll likely trim off later:
This completes all the fabrication involved in this short section - now it's just minor trimming, deburring, primer and riveting/attachment.
The last remaining part of section 29 was to install the landing gear mount, which required some primer touch-up where I "fixed" a flange to fit:
Landing gear mount flange after stripping the remaining powder coating
Touched-up landing gear mount
With that, I started the final step of bolting down the landing gear mounts:
Installed right landing gear mount
Installed left landing gear mount
All landing gear mount bolts torqued inbetween the center section spars
Of course, there had to be one bolt that gave us trouble and made us spend almost an additional hour to get it tight - it was just too close to the landing gear mount "leg" to use a socket, but we managed it:
Difficult bolt to tighten in the landing gear mount leg
With that, this section is 100% complete :) There is life after section 29!
Time lapse:
Total fuselage side skin rivets: 1714 Total fuselage side skin time: 156.9h
We had noticed some rust forming on the steel parts (e.g. for the control system and flap system), so we decided to prime all of those, as well as some other parts that would be helpful (like the floor pans):
Primed bolt access plate, floor pan, idler arm parts, tailcone shims, pushrods, flap torque tubes, landing gear mount and control stick base
Primed floor pan, control sticks, control stick base, flap horns, and step blocks
For a change, I'll include the times and videos with each section for which we did this.
I got started on section 39, the control systems, by cutting the pushrods to the proper length:
Pushrods cut to length and rod end bearings
Aligning the control sticks on the drill press table proved to be quite hard:
Mess trying to align the control stick and its base on the drill press table
so I gave up on that and decided to use the mill :) (big thanks goes to a coworker who helped me and taught me how to use it!)
Mill with the control stick
With the mill it was actually quite easy to drill nearly-perfect matching holes on the two parts with the control stick not just "supposedly parallel" to the table, but actually clamped down to it
Control stick firmly attached to mill table
I drilled them #15 and later finished with #12 by hand:
Control sticks temporarily attached to their bases
I also trimmed the bushings and stick bases to fit within the control column:
Control stick base bushings, one in the control column and one in the control stick base
and finally test-assembled the whole thing:
Control sticks with bases and control column attached
Some of the parts had some rust on the inside, so I gave them a good T-9 bath in preparation for primer (I'll obviously need to clean that off before applying the primer, the Prekote should help):
Control system (and flap) parts after applying T-9
Next steps are priming and assembling these parts, and continuing the assembly of the pushrods.
