Yeah, it's rough, but I"ll just have to suck it up. 
More Half-Baked Designs Thread
- Thread starter jqavins
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Here's a really silly one. Fins that are clipped washers, each decorated like a different kind of doughnut.
That would suit your profile picture very well.
I dunno...that looks fully baked to me.
I hadn't even thought of that.
Fried.I dunno...that looks fully baked to me.
My next project, after the Triple-V, will be a return to this. When I found the moving box with lots of my rocket stuff a week ago or so, I found the booster from this with a rebuild motor tube that I don't remember doing. I kept the sustainer for single stage use (not that I've ever actually flown it) and found that quite a while ago, so I could be ready for another ground test pretty quickly. Come to think of it, with the Triple-V going in slow motion, I might just get back to this before finishing that.
"Wavy". Or maybe "Standing Wave".
The two-stage looks like a fun rocket, I watched your ground testing videos. It seems like you're just about there, very nearly done. I think that your rear-eject idea ought to work.
I like the standing wave (or traveling wave), it reminds me of the rockets made from styrofoam cups back to back. Would that be a bunch of transitions?
I like the standing wave (or traveling wave), it reminds me of the rockets made from styrofoam cups back to back. Would that be a bunch of transitions?
I would propose the name: "How I became expert in making cardstock shrouds over the course of a single build".
Or The Back Massager.
I think it needs to be called "Mock Diamonds". Especially with that color paint job.
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You know, some of the single serve cereal cups are just about the right shape. Also some yogurt containers.
Or maybe "Mach Diamonds"
Or maybe "Mach Diamonds"
Yeah, that's what I was seeing! I just tried to get too cute with the spelling.
You could do the nose cone up to look like a liquid fuel engine bell, a little fancy painting on the "tube"...
I thought that the "Mock" was pretty clever, I like the play on words.
The Colorburst:
And, Teardrops:
And, Teardrops:
I wanna see the fin jig for Colorburst.
Whew, building Colorburst would be an exercise in fin glueing patience. But it would be cool to see it built. It might be a neat effect if it rotated on the way up, especially with those fin shapes.
Nytrunner
Pop lugs, not drugs
Very draggy. The airflow fin behavior would be....complicated
BTW since no one else has commented on it: I like Teardrops a lot. I kind of feel like I've seen something like it before, but I can't place where or when that might have been. It sort of makes me think of a rocket-ized Shuttlecock.
But it looks like it would be really hard to get stable. Joe, are those renders from Rocksim or just a CAD program? Curious where the CP ends up.
But it looks like it would be really hard to get stable. Joe, are those renders from Rocksim or just a CAD program? Curious where the CP ends up.
The fin shapes were the starting point. Their sequencing didn't show up well in the renders and I added the color sequence to enhance the shape sequence. And then I liked it. The jigging would be, well let's say interesting. With repeated applications of the Estes grey jig one get to 12 but not to 24. Or I could settle for just the 12. Carefully place one by hand in between two of the 12 then use the jig for the remaining ones. It should work.
The egg lofter nose on that one is just a placeholder. I wanted something besides a plain nose cone and that's what I came up with in a hurry, but I want something more, um, elaborate? Complex? Worthy of the tail.
I had the same impression when I saw it complete. I was inspired by the idea of having the same cone angle on the body and the fins; with the all tail cone body it shouldn't look like a shuttlecock, yet it does.
Rocksim. For scale, the motor mount is 24 mm (or is it 18? I did this one a long time ago and just got around to posting it) and it's minimum diameter at the aft end. It takes 20 g of nose weight to get to 1.0 caliber. At that point, the CG and CP are practically half it's length apart because the maximum forward diameter is so big. I'm confident that'd be OK.
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Teardrop looks good and stabile (-izable, anyway). Not a lot of room for recovery device.
Reminded me of the Birdie shuttlecock rocket too!
Reminded me of the Birdie shuttlecock rocket too!
I was thinking of one or more streamers, wound like a tape real, all together to make one disc that fits at the widest place.
I was looking at the NAR logo the other day, and this emerged.
I don't see a way in RockSim to model the fin extensions that are below the aft end of the tube. I added them in Paint to the side view.
The BT60 is there to give me a good place to pack a parachute. If I build it, the nose cone would probably be 3D printed, and the fins made from balsa plywood to make their aft points a little bit durable; I tried modeling it with 1/8" birch ply and it was too heavy, giving a stability problem. Maybe 1/16" birch ply would be better than 1/8" balsa ply.
I don't see a way in RockSim to model the fin extensions that are below the aft end of the tube. I added them in Paint to the side view.
The BT60 is there to give me a good place to pack a parachute. If I build it, the nose cone would probably be 3D printed, and the fins made from balsa plywood to make their aft points a little bit durable; I tried modeling it with 1/8" birch ply and it was too heavy, giving a stability problem. Maybe 1/16" birch ply would be better than 1/8" balsa ply.
That would be very cool if you can make it stable *and* survive a landing. Aw heck it'll be cool either way.
Glue-papering will add a lot of strength here, whatever wood you choose. If you paper with cardstock (something like 65 lb would be plenty), you should gain more strength than with copy paper, although you're adding weight.
For what it's worth, my Blackfish fins (3/32" basswood, glue-papered with copy paper) feel incredibly stiff. Stiff enough for your fins to survive a landing? dunno.
If you're so inclined, you could also take some 3/32" basswood and glass them. I bet that'd do it. No idea what the finished weight would be, but I always hear that a single layer of glass adds very little weight.
Standard approach in OR would be to add a phantom tube to the rear of the rocket, and mount the fin extensions onto that. I suspect that'll work in RockSim as well but you can try it and confirm.
I am unsold on balsa plywood's strength, especially for something like this. Maybe basswood?
Glue-papering will add a lot of strength here, whatever wood you choose. If you paper with cardstock (something like 65 lb would be plenty), you should gain more strength than with copy paper, although you're adding weight.
For what it's worth, my Blackfish fins (3/32" basswood, glue-papered with copy paper) feel incredibly stiff. Stiff enough for your fins to survive a landing? dunno.
If you're so inclined, you could also take some 3/32" basswood and glass them. I bet that'd do it. No idea what the finished weight would be, but I always hear that a single layer of glass adds very little weight.
- Stiff isn't the same as strong. The cross-ribbed corrugated cardboard I used on Office Supplies is very, very stiff, but there's no way it's be strong enough.
- My biggest concern is with grain breaks at the point. Which is something that plywood should help, no matter what wood is used.
- Papering is an idea I had in the back of my mind. I keep reading that paper doesn't obviate the need for correct grain direction, but the strength it adds otherwise would still be worthwhile.
- I should have thought of basswood as an option between balsa and birch. It's not like I haven't used it before. And I could make up some basswood ply just as easily as balsa ply. And paper it.
- Finally, you have a point that this might be the right moment to jump into fiberglass. I hadn't thought of that.
Dare I say... Rear eject???
Oh do. Dare. Dare.
Not a bad idea.
Not a bad idea.
Very cool! I like it, definitely build worthy. And Mugs914 has a good idea, this seems like a perfect candidate for rear eject.
Any particular reason you'd prefer a 3d printed nose cone over a balsa one? I didn't check BMS, but seems like a conical cone for BT60 should be available. The other option is to use a plastic one, cut out the base, and then you have a hollow volume which gives you a bunch more space.
I think a lot of fin material options would work, especially with rear eject. And 1 layer of fiberglass is surprisingly light (it surprised me). I'd do 4-5 oz glass (sounds heavier than it is). Also, I think that using a finishing resin is lighter than a regular epoxy (I didn't do a comparison with weights, but it sure seemed that way).
Any particular reason you'd prefer a 3d printed nose cone over a balsa one? I didn't check BMS, but seems like a conical cone for BT60 should be available. The other option is to use a plastic one, cut out the base, and then you have a hollow volume which gives you a bunch more space.
I think a lot of fin material options would work, especially with rear eject. And 1 layer of fiberglass is surprisingly light (it surprised me). I'd do 4-5 oz glass (sounds heavier than it is). Also, I think that using a finishing resin is lighter than a regular epoxy (I didn't do a comparison with weights, but it sure seemed that way).
I was assuming that interior space was the issue. Erockets makes some nice long BT60 conical noses, but that'll leave almost no room in there for the laundry. I'm not aware of a readily available long conic BT60 nose in plastic.
An alternate approach would be to use a balsa cone for the front part only, and use a paper shroud for the rest. If you're rear ejecting you could use filler at the joint and it would absolutely look like one piece. That approach does however require some sort of interior structure, which may or may not be practical here.
3D-printed might really be the best route, although heavy.
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