Here goes, my first scratch build. “Test to Destruction” gets its inspiration and its name from the fact that I want to try out a few building method ideas that I haven’t used so far. And I don’t want to try them out on a beautiful kit I dropped 20 or 30 bucks on! If I end up finishing off a build with a ball peen hammer, some lighter fluid, and a match, I want it to be one of mine.
It’s pretty much a bog standard 3FNC. LPR, BT-60. The fins are a little different in their shape but that’s about it. The parts are mostly ones I had in my spares box, basically leftovers from an Estes Patriot I bought and raided for parts. I bought a nose cone and a baffle kit for this, and will have to scrounge a thrust ring from a motor mount kit.
OpenRocket file and picture of a possible paint/decal scheme follow.
No, I’m not showing you the other half.
Right, let’s get started. Fins. I have a fin template. Thank you, OpenRocket. I also have 3/32″ balsa. I bought this for a scratch build my son was considering but that was weeks ago and he hasn’t touched it yet so it’s fair game.
I marked the corners with a compass point
I cut the fins out with a hobby knife. Metal ruler on the fin side of the line to keep me honest.
There was a rather shameful amount of mismatch between the three. Never mind, that’s why God invented sandpaper. On day three.
One of the things Test to Destruction is supposed to test is laminating fins with paper. I’m proceeding similarly to Chris Michielssen in his blog posts starting here. One difference is because Chris knows better than to make nonconvex leading edges he’s able to roll his paper over that edge. I’m just going to have to treat it like the other non-root edges.
I’m also not filling the balsa before papering it. Chris says he didn’t on the previous rocket and you could see the balsa grain. I look at the picture and say, “You can?” Maybe, but I’m not building for close-up inspection.
I’m doing just one fin first. If I like it I’ll do the other two the same way. If not, it’s hammer time.
I traced the fin twice on 20 lb copy paper, flipping it over in between.
I put an even coating of glue stick on the paper, laid the fin on it, flipped it over, and burnished it with a Sharpie barrel.
Despite italics, I still missed it here where Chris says “Let the fins dry overnight in a heavy book before trimming.” I used scissors to trim the first side close to the balsa edges. Immediately. D’oh!
Lather, rinse, repeat on the other side.
Yeah, I trimmed that side too. I am so going to Hell. And then I applied the heavy weight.
And now the heavy wait.