A lot of non-airplane building stuff has been going on the last few weeks so progress on the tail cone has slowed somewhat.
Last Friday I took a day off that also happened to have some good weather, so I finished priming some of the parts I'd had to put off.
I primed the J stringers, the two longerons, reinforcing angles for the bulkheads, the last part of the F706 bulkhead that had not been primed as well as the baggage ribs so all the center section would be ready. One of these days I'll remember to take a picture. There is a lot going on with getting all the parts cleaned for painting, mixing up the paint (it's a 2 part epoxy primer) then letting it "cook" for 30 minutes.
Next step was to remove the vinyl along the rivet lines, then debur and dimple all the skins, bulkheads and J stringers. Once that was done it was time to reassemble the tail cone and start riveting.
The F779 bottom skin is a pretty heavy piece - .040" thick. When I was match drilling it was very difficult to get it all pushed up so I could match drill the holes and J stringers. This time I put a little more pre-bend on the skin, then put it in by itself before adding the F711 and F712 bulkheads. The fit was *much* better not to mention it was way easier to get everything lined up and clecoed in place.
Van has you start off riveting the two aftmost bulkheads (F711 and F712), then the F779 bottom skin at the tail, then finally the main bottom skin.
Here is a shot of the tail cone as I'm starting to rivet it. I was able to use the squeezer on most of the F712 (furthest aft) bulkhead and a lot of the F711 bulkhead. You can see an elliptical hole on the lower forward part of this shot. There are two of these (one on each side) that will be where the rudder cables will exit the fuselage and attach to the rudder, which will be attached to the aftmost bulkhead.
Next they have you start working forward along the lower J stiffener line, riveting the J stringer, side skin and F779 bottom tail skin together.
Becca helped me with back riveting the tail cone bottom skins. It would have taken me a few hours to get as much done as she and I did in 30 minutes.
Here is the cone with all the bottom skins riveted on (it is laying on its left side). This is looking from the tail forward. Basically this section will be from the back side of the canopy aft. The baggage compartment, seats/cockpit and engine will all attach to the forward section of this piece. The tail will attach to the near end.
On Saturday I finally finished riveting the tail cone. I did a quick guesstimate count - close to 1000 rivets in this dude. Took a while. Back riveted almost all of it. The entire assembly probably weighs less than 30 pounds. Amazing how light all this stuff is.
Here's a view looking aft inside the tail cone. The lengthwise J-stringers add considerable strength. The F706 rib in the foreground will be riveted when the center section and tail cone are riveted together.
The vertical member is for the elevator bellcrank assembly. There is a pushrod from the control sticks that passes through the small hole at the bottom, attaching to the bellcrank which will later be mounted just aft of the bulkhead. The elevator pushrod will continue aft through the large round hole in the far bulkhead and attach to the elevator.
Next step is to start working on the center section. The plan view is below. The aft bulkhead supports the seat back. Aft ribs are baggage floor ribs. Forward ribs support the seats. The forward bulkhead is the main spar carry through structure.
Started fabricating the seat shims from 1 1/2" bar stock. 4 required.
4 of the seat ribs have to have the forward holes enlarged to provide clearance for the control columns. Two will be cut for an access plate cover. I used a standard hole saw in the drill press to cut the ribs. Worked great.
Here are the 2 916 L + R inboard ribs after the holes have been cleaned up.
Plan of the two ribs that have to be modified with access plates. Should finish those up tomorrow.
Finished up prepping the two access ribs, then riveted up all the seat rib nutplates. Next step is to cleco the aft portion of the F904 bulkhead to the seat ribs, the F705 bulkhead and the baggage ribs.
Then you cleco on the skin. I decided to flip it upside down to do that.
Here's another view from underneath.
Had some fit issues with the two center baggage ribs (F727 L+R) and the F705 bulkhead. Turned out to be interference between the rib spacers on the two access ribs and the seatbelt anchors. Once that was cleared up everything went together correctly.
