I have, let me see, six rockets in progress — Saber, Yankee, Photon Disruptor, Habanero, Sea Sting, and Jupiter C — and they’re all at the point where they need spray paint, and it was raining and windy Saturday. (The Saber’s been waiting for the next coat of primer for months, but I have reasons for not proceeding yet. The rest I think I can finish before cold weather sets in, maybe excepting the Sea Sting.) If things get really desperate I’ll start painting in the garage — while my wife’s out — but for now I’ll just wait and see what tomorrow’s like, and in the meantime start yet another project. I considered a cardstock rocket, something needing no paint other than clear coat which I could maybe get done in time for the launch a week from today, but no: I still have 2013 build pile rockets un-begun, and I need to at least begin them.
D-Region Tomahawk? I considered it. But I ended up deciding in favor of the MLAS.
This is a decidedly weird rocket. It’s a semi scale of a very obscure NASA launch vehicle built to test the Max Launch Abort System (MLAS), an escape system developed for Orion as an alternative to the Mercury/Apollo style “escape tower”. It won’t be used for Orion but something like it is part of SpaceX’s Dragon V2 human spacecraft. The test was done, successfully, back in 2009. Here’s a video:
If that’s not the strangest looking launch vehicle NASA’s ever sent up I’m not sure what is (but I want to build a model of it). Also, count the parachutes they used to bring everything back. I count nine of them.
You might think a rocket as short and fat as this, especially with forward fins, could not possibly have 1-caliber stability, and OpenRocket pretty much agrees with that. Of course OpenRocket (and Rocksim) doesn’t properly account for base drag which improves stability for stubby rockets, and this rocket is certainly stubby. Even so, and even with the bolt in the nose cone Quest includes for extra forward weight, stability is, as I understand it, kind of on the hairy edge. Quest recommends only B6-2 or B6-4 motors. They say a C6 is too heavy; it pulls the center of gravity too far back.
Another Syracuse Rocket Club member launched an MLAS last month, twice. On a B6 it did not have a good flight — didn’t get high enough for a good recovery. He told me another SRC member had had similar results with an MLAS. He launched again on a C6… and it flew stably and recovered well. Once. Don’t take that as assurance from me that you can do so safely, though.
Anyway, the overriding principle here is to build light, especially at the back. The design is frankly marginal, and you have to give it whatever help you can.
The fins in my kit came like that — the balsa sheet had broken and most of the fins were loose (but undamaged).
For some reason I seem to have two sets of Kevlar/elastic shock cords (plus the thin Kevlar for the nose cone chutes).
The body tube had an issue: Maybe I would have been well advised to send this back and ask for a replacement, but I bought it at a clearance sale at half price so I figured I’d just fix it up myself. I tried trimming the end of the tube with a hobby knife; the result was rather uneven, though arguably still an improvement. Not good enough, though. So I applied thin CA around the inside of the end of the tube. When that dried I took the coupler tube (which will be used on the nose cone eventually) and one of the centering rings and stuck them into the tube near the bad end, secured with tape. That stabilized the tube (it’s otherwise very thin and very flexible, again for rear end weight reasons), so I could push it around on a piece of sandpaper taped to the table. The result is still not perfect but a lot better. I don’t think I’ll even notice the imperfections once it’s built.