More Half-Baked Designs Thread

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jqavins

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Thanks. I should get to the RS attempt(s) today or this weekend. I'll remember to try lengthening the boat tail as well as its rear diameter.

I'll keep y'all posted.
 

BABAR

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Has anyone done this? I bet someone has done this. Boattails move one's CP forward. Ringtails are quite effective at moving one's CP aft. When a boattail is placed inside a ringtail, which one wins?
View attachment 464060
The ring's pylons are visible in the bottom view. If it helps, the pylons could be extended forward to fill the boattail's profile up to the bottom of the body tube, but I bet that wouldn't help much if at all.

Looking at it, I see that it's similar to some air dropped bombs, and also to some torpedoes. But torpedoes can have guidance systems (the modern ones all do, if I'm not mistaken) and the bombs only have to be nominally stable.

Of course I could, and will, try it out in RS, and maybe OR too. (Wait, are ringtails that feature that OR lacks until the next release that's been just around the corner for a couple of years, or are ringtails available today?) I'm just not sure how far to trust the simulations for a model that's rather far, but not terrifically far into the weirdness zone.

If this works, it just begs to be tube launched. Before I spend the time to do the research, does anyone happen to know of a standard BT size (OD) and a common pipe size (ID) that are a good match for the purpose (close but not tight)? Don't trouble yourself looking, as looking is my job unless someone already knows.
@Dotini did something like this.

see post 47

AnimistRingFin.jpg
 

Sooner Boomer

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Has anyone done this? I bet someone has done this.

If this works, it just begs to be tube launched.
you mean...



I'm amazed you don't remember posting to this thread! But please, put your own spin on it! I'd love to see what you can do!
 

Dotini

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@Dotini did something like this.

see post 47

View attachment 464232
Dotini also did this, Animist II, big brother to the Animist seen above.

DSC00235.jpg
DSC00234.jpg


I can add that it is very sturdy and can take a rough landing. It goes very high, does not weathercock, and seems to be a natural backslider.

I suppose if someone wanted to tube launch it (but why?), they could add a canard ring or canard fins to center it in a tube.
 
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jqavins

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you mean...
No, I mean what I sketched in post 141. The ring is the same size as the airframe (unlike Dotani's) and there is no stand-off pushing the ring back.

I did it up in RockSim over the weekend and then it slipped my mind to post it. RS says it's stable and has very surprisingly high drag. I'll try to remember to post tonight.
 

BABAR

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Dotini also did this, Animist II, big brother to the Animist seen above.

View attachment 464762View attachment 464761

I can add that it is very sturdy and can take a rough landing. It goes very high, does not weathercock, and seems to be a natural backslider.

I suppose if someone wanted to tube launch it (but why?), they could add a canard ring or canard fins to center it in a tube.
Again, nice look.

did this actually BackSlide with nose in place? I have seen many streamer and parachute rockets that have what I call a “Pseudo-BackSlide”. (Which may not the that “Pseudo”). Basically the deployed the nose and chute or streamer, nose came down hanging on the chute or streamer, the body of the rocket (still attached to nose and streamer) turned horizontal tail first with very slow tail first trajectory parallel to horizon will it fell, maybe better out, it descended attached to but parallel with the nose cone and chute, so it wasn’t “dangling” from the chute, in a horizontal orientation, and seemed to have a minimal added “backward” trajectory.

this seemed to happen more with my asymmetric fin rockets. I am pretty sure that asymmetric fin rockets need more fin area to be upward flight stable. They are not very efficient, I am sure I sacrifice some altitude, but good enough for government work or sport flying, and I think on my few flights with spectators they get a few more ooohs and aaahs (due to corkscrew smoke trail) than more classic and efficient 3FNC low and mid power rockets.
 

Dotini

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Again, nice look.

did this actually BackSlide with nose in place? I have seen many streamer and parachute rockets that have what I call a “Pseudo-BackSlide”. (Which may not the that “Pseudo”). Basically the deployed the nose and chute or streamer, nose came down hanging on the chute or streamer, the body of the rocket (still attached to nose and streamer) turned horizontal tail first with very slow tail first trajectory parallel to horizon will it fell, maybe better out, it descended attached to but parallel with the nose cone and chute, so it wasn’t “dangling” from the chute, in a horizontal orientation, and seemed to have a minimal added “backward” trajectory.

this seemed to happen more with my asymmetric fin rockets. I am pretty sure that asymmetric fin rockets need more fin area to be upward flight stable. They are not very efficient, I am sure I sacrifice some altitude, but good enough for government work or sport flying, and I think on my few flights with spectators they get a few more ooohs and aaahs (due to corkscrew smoke trail) than more classic and efficient 3FNC low and mid power rockets.
Yes, agreed on all points. Animist II backslid on a flight in which the streamer failed to deploy properly (I had left the rubber band on it). I've noticed this on other flights with proper deployment as well. IMHO, there is a lot to be said for models which land reliably without loss or damage, and do it over and over again. In only a short time, I will reveal my new pseudo backslider which will try to live up to that particular set of virtues.
 

BABAR

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OK, here it is. The is the BT-60, 18 mm version. I shall name it "Fire One!"
View attachment 464936View attachment 464939View attachment 464940View attachment 464941
I was thinking, “Fish in the water!”


might be a nice model for rear end ejection. Plenty of space.
 

jqavins

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I just ordered parts to make a quick and easy prototype. Bit Bertha nose cone and V2 boat tail with a BT-20 core hole. NYPower is a week away, and I just might have it ready to fly (built and swing tested) by then. It'll probably have to have launch lugs this time. (If I can't get a proper pipe size, I could use FARGs, but I don't expect I could get those ready by next weekend.)

Correction: Ordered the Apogee FARG for it.
 
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Dotini

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I just ordered parts to make a quick and easy prototype. Bit Bertha nose cone and V2 boat tail with a BT-20 core hole. NYPower is a week away, and I just might have it ready to fly (built and swing tested) by then. It'll probably have to have launch lugs this time. (If I can't get a proper pipe size, I could use FARGs, but I don't expect I could get those ready by next weekend.)

Correction: Ordered the Apogee FARG for it.
Who do you order those desirable Estes parts from?
I'm very interested in your experiment, and intend to keep making ringtails myself, and access to those parts short of buying the full kit might suit my plans very well.
 
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jqavins

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I ordered them from Balsa Machining Service. It would have been more precise to say Big Bertha nose cone and V2 boat tail equivalents, but in solid or cored-out balsa. When I do this full scale, 3 inch body and 29 mm motor mount, I don't know where I'll find the parts. But I'll cross that bridge when I come to it. It may just be the kick in the ass that I need to try some fiberglass fabrication, but if I can buy the parts rather than make them I will. (I'd rather build rockets than rocket parts, but that's me, and your millage may vary.)
 

Mike Haberer

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I do indeed. Id' be happy if this thread becomes like that one, sims not required.

Well, this one's even less than half baked. And actually it's two. Y'know the design with a ringtail internally tangent to the body tube? Or a single tube fin attached on the opposite side from it's centerline, if you'd rather call it that. What about applying two of those rings, with interlocking slots where they pass each other? That'd look nifty, wouldn't it?
View attachment 394764

And what about one of these tangent ringtails but with the ring actually a Möbius strip? Oh, sure, the twisting of the ring would certainly play hob with its aerodynamics. That's OK, fix that by making the arrangement symmetrical by using two like the picture above. (Yeah, I did say "less than half baked".)
---------------------------------------------
Come on, somebody else!
Already been done. See attachment. One of the best flyers I've ever built.
 

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neil_w

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Already been done. See attachment. One of the best flyers I've ever built.
Ooh, you built that one? I'd love to see some pics, and also hear how you did the paint sequence. It's a beautiful design, looks like the sort of thing I would design only a lot better.
 

Mike Haberer

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Write now it's only primed, the weather has only gotten warm enough to paint in the last week. I haven't decided on the paint scheme yet; unless it's all one color it's going to be a masking nightmare.

I've flown it twice so far on an E30T and an F44W. The most amazing thing is most rockets fall somewhat short of the Rocksim altitude estimates. This bird has exceeded the estimates on both flights, by 14% and 40%, respectively. Flies straight as an arrow. It's one of my all time faves.
 

jqavins

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That's a beautiful design. I may need to add that to my virtual build pile. (Since the pile is virtual, it doesn't matter if no kit exists.)
Ooh, you built that one? I'd love to see some pics, and also hear how you did the paint sequence. It's a beautiful design, looks like the sort of thing I would design only a lot better.
Careful. Internally tangent rings are dangerously close to tube fins. And you shun tube fins. ;)
 

neil_w

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That's a beautiful design. I may need to add that to my virtual build pile. (Since the pile is virtual, it doesn't matter if no kit exists.)
Careful. Internally tangent rings are dangerously close to tube fins. And you shun tube fins. ;)
I have created a number of designs with interlocked rings like that. Regrettably none of them are as nice as that one.
 

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I have parts for but haven't yet built a triple-interlocked internally tangent ring using 6" fins and a BT-80 body tube. It'll fly on larger 24mm motors. I want something relatively draggy so I can fly larger motors on a smaller field.
 

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