lcorinth
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I started building this around the same time I started my Leviathan build (thread here).
For a while, the Nike Smoke was progressing much faster than the Leviathan, but the Leviathan is now finished, while I'm still wrestling with paint on the Nike Smoke (you'll see what I mean later in this thread). My planned L1 cert flight will be in September, so if I finish this rocket by then, and if I change my mind about the Leviathan (or if something happens to it), this will be my backup.
Shortly after opening the package, I stacked the nose cone and body tube together, just to see what it would look like. Up to this point, this was the largest rocket I had worked on. I was pretty impressed.
While it's often a good idea to lightly sand the body tube on rockets with externally-mounted fins for better glue adhesion, on this rocket, it's really necessary. The tube is so slick, you can barely make a pencil mark on it. I used a sanding sponge and kept it light, as there would be some more sanding later. Then I marked the a line for either launch lugs or rail buttons. I hadn't decided which to use just yet.
The fins are made of plastic and come in two parts, which must be glued together before installing onto the rocket.
They snap together, as you can see, but when dry fitting them, it became obvious that they don't fit perfectly. There is a gap around the edges. Still, they're nice fins.
I wasn't sure what adhesive I wanted to use to glue the fins together. The instructions recommend CA. I also considered 5-minute epoxy, as was recommended to me by someone online.
My worry about epoxy was that I'd have to pinch the fins together to keep the gaps closed while the epoxy cured. I might get some oozing out onto the edges, and not be able to clean it up before it cured. I'd need both hands free to hold the fins tightly together.
While thinking about what glue to use, I went ahead and started assembling the motor mount, beginning with the middle centering ring, which is the one with the grooves cut into it.
I often mark the forward and aft ends of my motor tubes ("F" and "A") to make sure I'm putting things together correctly.
The green paper ring helps you get the centering rings on perfectly straight. It slips over the motor tube, and you put the centering ring up against it, and glue the centering ring in place with a fillet. Then you remove the green spacer ring and fillet the other side of the CR.
The spacer ring is then used to keep the forward and aft centering rings straight.
Finally, you glue the green spacer onto the forward end of the motor tube. It probably isn't necessary, but it may add a little bit of support to the centering ring, and you don't have anything to throw away.
Once the motor mount is assembled, you can see how the fin (which is just dry fitted together here) snaps into the middle centering ring, assuring perfect fin alignment.
At this point, you can even dry fit the whole rocket together, by putting the motor mount into the rocket (not gluing it just yet!) and inserting the fins. It all snaps into place, and you can see what the finished product will look like.