I continued the work on the empennage fairing by drilling the nutplate holes for its screws:
Vertical and horizontal stabilizer nutplate holes
Vertical and horizontal stabilizer nutplate holes
Unfortunately, most of those holes actually were on or very close to the flange flutes. I was afraid that a solid rivet would expand in that space, and didn't want to flatten the flute, so instead of dimpling and riveting with solid rivets, I machine-countersunk and used CCR264 nutplate blind rivets, which worked out well:
Vertical stabilizer nutplate holes overlapping the flutes
Vertical stabilizer nutplates attached with CCR264s
On the horizontal stabilizer, I did dimple and use solid rivets (except for two holes which were too close to the edges of the rib flanges, so I countersunk those):
Horizontal stabilizer fairing nutplates attached
We continued the sand-fill-repeat process on the bottom rudder fairing, and got a lot closer to a good finish:
Bottom rudder fairing with primer applied to spot pinholes
At this point, we, of course, sanded it again as several pinholes became evident - and squeegeed another layer of resin with some flox in:
Bottom rudder fairing trailing edge after another layer of resin
We laid up some epoxy and flox around the elevator fairings to make a smooth transition:
Forward face of the elevator fairing filled with resin/flox (unsanded)
Gap between fairing and elevator filled with resin/flox (unsanded)
After that comes a lot of sanding to make a smooth transition on all of them. So far we only did the forward faces, and even those still need a lot of pinhole filling:
Forward face of left elevator fairing, before filling pinholes
Forward face of right elevator fairing, before filling pinholes
We attached the empennage parts together (at least temporarily), starting with the stabilizers:
Horizontal and veritical stabilizers mounted in place
Fuselage, tailcone and stabilizers all together!
Full-airplane view with the stabilizers on
We attached the elevators, measured and adjusted their travel:
Elevators attached to the horizontal stabilizer
Lower travel limit at ~24˚
Upper travel limit at ~28˚
To get it to the target range (25° down, 30° up), I had to file down the elevator stops a bit:
Slots filed down to increase upper elevator range
Slot filed down to increase lower elevator range
Bottom view of elevator range slot
Final lower elevator travel at ~25˚
Final upper elevator travel at ~30˚
This, unfortunately, created the need to comply with SB18-03-30. It was only then that I realized - and Van's support confirmed, that I didn't need to do any of this :/ instead, the section on flight testing specifies a range of angles, and my original values were within that range, so I'll likely just replace that angle with one that's untrimmed.
With all the parts attached and adjusted, it looked pretty impressive, and gave a real sense of progress:
All empennage parts attached to the fuselage
I'll take advantage of having all these parts on to work on the empennage fairings, before I pull them out again, address the SB, and store them away until final assembly time.
I'm going back to finish section 11 in order to be done with all the tailcone drilling before attaching it to the fuselage, since it'd be quite a bit harder to do afterwards.
I installed the rod end bearings into the elevators:
Rod end bearing attached to elevator
I then attached the elevators to the horizontal stabilizer to match-drill the bearing into the elevator horns:
Elevator attached to horizontal stabilizer
Both required some adjustment (loosening up a half turn of the rod end bearings) for the bent-edge blind rivets not to catch on the rear spar rivets, but it was fine after that.
I attached both at the same time to drill the pushrod attachment bolt hole at the bottom:
Elevator horns attached to horizontal stabilizer bearing
Both elevators attached to horizontal stabilizer
Drilling the pushrod attachment hole on the elevator horns
I then removed the elevators and match-drilled the horizontal stabilizer to the tailcone:
Horizontal stabilizer aft holes attached to tailcone
Horizontal stabilizer forward holes attached to tailcone
Horizontal stabilizer attached to tailcone
Since I'm also working to rebuilding part of the vertical stabilizer, I also match-drilled the rear spar into the tailcone:
Vertical stabilizer rear spar attached to tailcone
I removed and put away the HS and VS, and will prime the shims on the next primer batch. After that, the next time I come back to this session will likely be for the final attachment.
Time lapse:
Total empennage attach rivets: 40 Total empennage attach time: 20.8h
The horizontal stabilizer is 100% done after only 137.1 hours of work (and re-work, and re-re-work):
Completed Horizontal Stabilizer!
The longest part of it was riveting the ribs to the skins - several rivets had to be set multiple times (they're close to tolerance, and I assume the layers of primer bring me even closer to that, so I had to up-size a few of them):
Riveting ribs to skins
Riveting ribs to skins
Another important step was to figure out where to install nutplates for bonding with the elevators (where the static wicks will live). From several posts from other builders, such as Mouser (thanks again!), I ended up deciding on using the hinge brackets themselves, and I wanted to use the most inboard brackets as that reduces the forces acting on them:
Bonding strap screw hole
Nutplate for the bonding strap screw
Once that was done and every inside rivet was checked and re-checked (and some replaced), I attached the rear spar to the ribs and then to the skin:
Rear spar ready to be riveted to the HS
While attaching the last side of skin to the rear spar, I had a small misalignment issue:
Oops, those holes don't match!
It was less than 1/32", but enough to make rivets not go in straight:
Diagonal rivets :/
I eventually fixed it (with help from VAF once again!) by slowly using a dimple die to bring the skin to alignment around a hole, then clecoing the next hole (and repeating that for every other hole in the spar).
Now, on to finish the elevators! (already about halfway done)
Time lapse:
Total horizontal stabilizer time: 137.1h Total horizontal stabilizer rivets: 1292 Total empennage time: 311.5h Total empennage rivets: 2101
