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PostPosted: Mon Nov 29, 2010 11:25 pm 
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We all have our own methods for getting fuselage segments joined up nicely, but I thought I'd note down techniques I've found helpful. Excuse the lack of pictures - hopefully my descriptions will be clear enough without them. These techniques are for flush joined segments using glue strips, which I use as much as possible (even to discarding the extra bulkheads in butt joined fuselages and fabricating my own glue strips instead).

1. Don't start at the center & work fore and aft, which is the "standard" approach. Instead start with the tailcone & work forward. Why? Because this sequence makes it easier to get good adhesion to the connecting glue strips (you'll see why shortly). The tailcone is the only piece that has connecting strips at only one end (except the nose, but the tailcone is easier to start with).

2. Precurl the beejesus out of the fuselage section. You want it so it's fighting to come together, not come apart.

3. Don't V-notch cut the glue strip. This makes flat areas that sometimes show through. Feathercut it instead: cut slits about 2mm apart. This is tedious but not that bad - if you cut a slit too deep it doesn't matter so you can go pretty fast.

4. After feathercutting them, precurl the glue strips, before gluing them onto the joining edge of the fuselage section. This prevents pucker caused by the circumferential difference between the section and the strip.

5. Make the logitudinal section joint an overlap joint, NOT a flush joint. If you make it a flush joint the stresses will inevitably crease the glue strip, putting a break in the smooth curve of the underside. Keeping the joint as an overlap joint also creates a natural "fudge" factor if the piece geometry isn't right on (most have some error). Because this joint is almost always on the bottom, the fact that isn't flush won't be terribly visible - and considerably better looking than if it were flush but creased. Of course, tint all edges before assembly, which further hides overlap joints.

6. Now that you've got the tailcone glued up, DO NOT put the bulkhead in. Wait. If you put the bulkhead in now, you'll create a stress ridge that'll show through as you press the next section into place. So stow that bulkhead for now. And throw away its mate if converting a butt joined fuselage to a flush joined one.

7. Curl the next section, feathercut the glue strips and curl them and glue them into place. Do not glue the longitudinal seam yet.

8. Find alignments marks that will work and glue about half an inch of the sections together on those marks. With the bulkhead not there you can use a dowel or your fingers to clamp the joining strip and press it secure. Once that initial joint is dry, glue up the rest of the joint, but don't glue more than you can control at one time, so it may take two or three or four steps of gluing to close up the joint. Again, because the bulkhead isn't there, it's easy to apply clamping pressure and make a tight joint.

9. Now close the longitudinal overlap joint.

10. Finally, it's time to put that bulkhead in there. It's deep, so a hemostat or tweezers will be handy. Now, you don't want to put it in tightly. Jam it in there and you'll create a stress ridge around its circumference. The beauty of this method is you don't need a terribly accurately shaped bulkhead, it only needs to be close. It's there just to prevent collapse and help set the shape. First, bend the bulkhead halfway over so you can grab it with the hemostat or tweezers. Glue half an inch of the aligning edge and set it in place where it starts to fit snug. If it's not on the joint seam, it doesn't matter. It's not there to reinforce that seam, it's there just to give some shape. Once it's dry, push the bend back more or less flat and lightly snug into the fuselage and glue.

11. Repeat 7 thru 10 all the way up to the nose. Some modifications to the method may be necessary if you've got a detailed cockpit or other fuselage accessories to be accommodated (inlets, vents, etc.).

Hope this helps.


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PostPosted: Tue Nov 30, 2010 7:20 am 
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Supreme Paper Commander
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Location: Papillion, NE
I like it! I've used many of those tips myself.


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PostPosted: Tue Nov 30, 2010 9:11 am 
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Paper Model CINC
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Joined: Wed Jul 02, 2008 10:29 pm
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Location: Eastern Oklahoma, US
Kid! Good to see you active again! Thank you for the tips. I'm considering building a tiny, little airship and tower once I finish my current project (hands are acting up) this will help.

Lep

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