Again some work on the seatback bulkhead. On the upper part I had to install an angle and some aluminium part tha gets first bended. The angle is to be installed at 1/8" from the upper part of the bulkhead, to maintain the distance I us two 1/8" drill bits.



Then the plate gets bend by 4°, I did this by maintaining the part between two wood blocks. I had to tweak it a bit to make it work.



Here is the upper part of the bulkhead showing the two possible positions of the seatbacks.



Then I finished the angles I had cut last time. First they get drilled into position and then the slot get drilled to. I first drilled two holes at the ends of the slot, and then used a cutter in my small grinder.



Here all the parts are assembled, I still need to coutersink for all the flush rivets and then deburr everything.

The next bulkhead is sturdier, it will support the aft wing spar, the seat backs and the harness. I begin by cutting and fabricating some reinforcment bars and spacers, the all this gets backdrilled. Then all the harness anchors have to be installed. This is the picture when all is done.



I stumbled upon a problem because I had misread the plans about the drilling of the anchors. Here is a picture of the last one I installed and you may notice that bolts are not placed correctly, the one on the right is to near of the vertical part of the anchor and does not sit properly, all the assembly should be shifted slightly to the left. I'll order new parts for this.



I then cut some angle that I will then have smoothe and drill next time

Another session working on the aft fuselage bulkheads, they get bigger when moving to the front of the aircraft. The three bulkhead on the picture were first fluted, then the holes for the ruuder cables, static system and wiring runs were drilled.



The biggest bulkhead is the one just aft of the bagage compartment. The elevator bellcrank is to be mounted on this part. There are some aluminium angles to cut, drill and deburr. Here all the parts are clecoed together.



The lower part of the bulkhead has been drilled for the wirings, I will have to find a method for the drilling half holes on the ribs you can see through the holes.



Here is how the bulkhead looks with all the parts clecoed together.

Today I began working on the bulkheads, beginning from the back. The two aft bulkheads will also support the empennage, some holes get only drilled at the empennage fitting stage so one has to carefully study the plans.
Here is the most aft bulkhead, it allows also to fit a tie-down ring. The tie-down support has to be cut, drilled (but not all the holes some will get drilled during empennage fitting), and the tie-down hole has to tapped.



For the next bulkhead, two bars and an angle need to be cut and back drilled. On the bars you can the the lines along wich I could cut them to save some weight. I think I'll leave them as they are, the cuts are quite long to make and I would risk messing up something.



For the next bulkhead, again an angle to cut and drill. The two big holes are drilled, they will allow passage of the rudder control cables.



The last bulkhead is the easiest, only deburring and fluting to do. Those two operations have also been done on all the parts fabricated today.

Two hours were necessary to dimple and coutersink all the firewall parts. First the firewall was dimpled using the C-frame.



Then I coutersunk the other parts, I used a small steel jig, that avoids that the pilot of the coutersink tool wobbles around and elangates the hole.
Now, I only have to prime all this, but I'll have to wait for warmer temperatures.