Levelling the twist in the Aft Fuselage - 4 hours

A couple of evenings in the garage with not a whole lot to show for it. I dug out the plumb-bobs and set up to remove the twist out of the aft fuselage. Setting up the plumb-bob for the back is vary easy, but a bunch of time spent figuring out how best to hang the plumb bob out front. The angle of the bulkhead prevents the plumb-bob hanging from a cleco hole above. In the end I used a long aluminum angle to line up the backbone of the airframe, and then suspended the plumb-bob off of that.



To help ensure everything was straight. I used levels across the top as well.

If that wasn't enough...I made extra sure checking plumb-bob alignment with the laser. (I was a little unsure how aligned the angle at the top of the bulkheads was....this proved it)

Completed final fitting of the aft fuselage - 4 hours

A big day in the garage for a weeknight. I just cant seem to get 100% fitment on the F-779 and F-773 side skins as the lower J-stiffners are in the way. I've decided to remove the lower J-stiffeners in effort to get access to fully cleco the F-779 bottom tail skin. I've read as much as I can on other blogs and after much thought, I've decided that this is the only way I can make all of the aft fuse fitment work. The idea is to plumb, and match drill everything. Then reinstall the lower J-stiffeners into the assembly and finally match drill those very last. That's the only way I can see I can get a full proper cleco as it's just impossible to fully cleco the assembly.

Before I disassemble for the millionth time to remove those stiffeners...I needed to address how I transition the stiffener along the side skin to the F-779 tail skin. Doing nothing there is quite a gap to deal with. If I rivet it with doing nothing, there is an area of potential stress to bridge this transition. I've put a question to the forums as nobody seems to address it on the build logs.





Update - With a little research and thought, I will file down the sharp edge on F-779 (similar to the lap joint on the wing skins) so that I do not have a hard 90deg edge digging into the J-channel after I rivet the assembly.

With the lower stiffeners removed....I managed to get everything clecoed up. Again...Not going to sugar coat it...Its a fight right to the end. Everything boils down to a specific method and progressive pattern to cleco in order to get it all done. Each cleco on the tail bulkheads are smothered in boelube before forcing into the holes. Ugh....But in the end I prevailed.


Much thanks to my good friend Mike A.K.A. @inspiringpursuit (Who's building both the F1 rocket and the Stewart S-51 mustang) who stopped by to give advice, encouragement and checked my work when I was uncertain.

Further fitting of the F-712 and F-711 bulkheads - 8 hours

Very long and annoying day in the garage these last few days. I've been spending a few hours an evening messing with the fitment of the F-712 and F-711 bulkheads to the F-779 skin. Lots and Lots of fussing. Its quite a process to get things tweaked to finally be able to get them fully clecoed to the bottom tail skin. I won't sugar coat it, the process is extremely frustrating and I've lost a bit of sleep thinking about if I've done something wrong, or if I might be wrecking things. Once I was able to get the fit decent I then clecoed it to the aft fuselage and soon realized....I need to work the bulkhead tabs some more. ugh.




A good look of how I still need to tweek the fit so the bulkheads align better with the fuselage sides.

Final fitting of the aft fuselage - 8 hours

Very long and frustrating day. I started the day with a little research on how at the tail pieces fit together to make sure all is good. A little head scratching but the F-710 bulkhead sits above F-779 bottom tail skin, which sits on top of F-778 bottom aft skin and the F-773 side skins.

But now the real challenge is having everything line up when clecoing....but it doesn't.
I don't know where to begin. I've clecoed and unclecoed some many times. Its very difficult and extremely frustrating. I managed to get the assembly pretty good, but the F-710 bulkhead is really really tight and rippled which did not sit well with me. Also I cannot fully cleco the F-779 bottom tail skin as the lower J-stiffener is in the way. Here is as far as I got.

Began final fitting of the aft fuselage - 6 hours

I needed to disassemble the aft fuse in order to start to devinyl the skins. But before I could reassemble I needed to ensure my sawhorses are level. My garage floor is fairly poor when it comes to how level things are. I built a frame on the floor to place the sawhorses on, and leveled that frame.


I then got to work de vinyling the aft fuse skins. A fairly long process but I assembled as I went.



I then started to look how to fit the F-710 bulkhead into the fuse.

Started initial fitting of the Aft Fusalage - 5 hours

One of the items that I didn't fully complete was finish cutting the J-stiffeners. It's not entirely clear from the plans and manual if J-stiffeners cut trimmed on each ends. Also, I'm leery to cut the J-stiffeners to length as per the plans or should I be leaving them long for best bit. Once I started lining things up, I could see that I did in fact need to trim both ends of A,B, and C stiffeners per the detail on the plans and also that the length stated on the plans is bang on.

Update - For the notch that gets cut into the ends of the J-Stiffners (as detailed on the plans), Notch both ends of the two longest stiffeners. The shortest J-Stiffener that goes on the top only gets notched on one end. Really, in order to assembly the aft fuselage you only need to cut and notch the two sets of longest J-channels. So you can always leave the 3rd (short) set till much later.

After marking the ends per the plans, I rough cut them on the band saw and then using the 3M wheel they were easily shaped to final form.

Next I began a lose fit of the F-712,  F-711 and F-710 bulkheads to the F-779 tail bottom skin. I knew from reading the various blogs that the bottom skin needed some TLC to fit the bulkheads better. It was easy to see how off it is.


I could also see how I needed to angle the flanges on the bulkhead. Yup, lots of adjustment needed.

I decided to hand bend the F-779 bottom skin, I took my time and slowly worked at it.


I finished up the day with clecoing the Aft fuselage to check fit.

Completed the F-711 bulkhead assembly - 0.5 hrs

Now that the primer from last nights fix is dry, I finished setting all the remaining rivets. Short and sweet. Bulkheads are now done.