J-stringers October 17th, 2010
The J-stringers run the full length of the tailcone. There are two on each side and two on the top. in order to fit between the skin and the bulkheads, the ends need to be modified as shown in the drawings.
I decided to leave the ‘tab’ a little wider than indicated, because it looked like the dimensions on the drawing would end up causing the rivet holes to be too close to the edge for my taste.
Assembling Tailcone October 17th, 2010
The tail cone skins with no bulkheads are large, flimsy and unwieldy. I used some masking tape to more or less hold them in place before adding the bulkheads.
Once the first few bulkheads are installed, it starts taking shape nicely. The pieces sitting on top of the tailcone are the stringers that will be added on the sides later.
Riveting the Firewall October 16th, 2010
Riveting the firewall is pretty easy, with a couple of exeptions. Here is the firewall ready to get riveted. Note that the firewall recess can be installed later to make accessing the cabin easier during assembly. Also, I have not decided if I am using a fuel injected or carburated engine, so I have not drilled the fuel pump doubler plate yet (I understand this is not needed with a fuel injected engine).
Most of the rivets can be back-riveted. The flanges on the firewall point ‘down’, so I had to use a few pieces of plywood/MDF to make sure the flanges cleared the table.
The rivets on these lower angles are too close to the angle to use a ‘normal’ back-riveting tool. I tried a couple of approaches, including a pneumatic squeezer and the arbor from my c-frame dimpler. It turns out the easiest way to rivet these is to take out the plastic piece off the back riveting set, and just hit the rivet directly. You have to go a few hits at a time to make sure the narrow set does not bounce off the rivet and ding the angle, but it is definitely doable.
Here is the end result. Note I scratched the paint on the angle, but there are no deep scratches. If I were to do this again, I would just make sure to use some masking tape on the angle to keep the set from rubbing against the aluminum when setting the rivets.
F-729 Rib (Vertical Rib on F-706 Bulkhead) October 11th, 2010
This rib mounts horizontally on the F-706 bulkhead. It helps strengthen the bulkhead and it also one of the attach points for the elevator bellcrank. Not much to it other than the rib itself and the reinforcement angle.
Riveting rear bulkheads October 10th, 2010
Riveting the rest of the bulkheads in the tailcone is also pretty straightforward. This is the F-706 with just a few rivets to hold the three pieces together.
And the F-707 with all of the rivets on the bottom and only two on the top (the other two are used for a piece of angle that holds a rib between F-707 and F-706.
F-711 gets the doubler bars that eventually are used to attach the empennage.
Note that the horizontal angle is not riveted on yet — just clecoed in place for now.
Finally, F-712. Note that the tail tiedown extrusion is also not riveted just yet.
Riveting F-705 Bulkhead October 7th, 2010
The F-705 bulkhead is the dividing bulkhead between the seating area and the baggage compartment. This bulkhead also includes the ‘fork’ where the rear spar of the wings attach to the fuselage. Only a few rivets need to be set at this time. These are mostly to hold together the lower horizontal section of the bulkhead to the two vertical sections, and the rivets that attach the doubler bar to the bulkhead. Even then, there are quite a few rivets in the doubler bar that are set later. Every place with a cleco in the picture below gets riveted later.
The F-705 bulkhead also holds the flap mechanism, and there are two ‘bearing blocks’ that need to be bolted to the bulkhead. These plastic pieces need to be drilled for bolts first.