- Joined
- Aug 27, 2011
- Messages
- 11,594
- Reaction score
- 6,215
Last one will squirrel, but the net trajectory will be straight. I have flown and successfully recovered and REFLOWN more eccentric designs
Neil_W's half-baked design thread
- Thread starter neil_w
- Start date
Help Support The Rocketry Forum:
Yes, but it's not yet a realistic model yet (interior not modeled at all, component weights all wrong, etc.) Stability issues on non-symmetric designs have always vexed me a bit. I think that asymmetric drag might be the biggest concern, although the two stabs are not really creating that much on top. I was thinking about putting a scoop on the bottom to offset. Need to do a lot more thinking on this design still.
No, it's way weirder.
Yeah, its similarity to some of your box-fin designs did not go unnoticed. I'm not sure if there's a way to balance out the drag on the bottom to straighten it out. I was thinking of moving the motors that are shown embedded in the wings to the underside, which would probably help a bit, maybe not enough. Haven't tried putting this one into OR yet.
For the underside, the Quest Force 5 used two parallel strakes. They're not all that different from the one you've got, and a second one would help (a little) with balancing the mass, drag, and fin effectiveness. Of course, spreading out two strakes is made easier by the Force 5's triple tube, but I'm sure you can work that out.
On the other hand, if you add a scoop to balance out the drag, you could also make it into a tube fin. Admittedly a scoop you can see through kind of spoils the illusion, but it would certainly help with stability.
On the other hand, if you add a scoop to balance out the drag, you could also make it into a tube fin. Admittedly a scoop you can see through kind of spoils the illusion, but it would certainly help with stability.
It would not be dynamically stable since depending on the cross winds and other forces, there might be insufficient stabilization along one axis
- Joined
- Aug 27, 2011
- Messages
- 11,594
- Reaction score
- 6,215
Nifty. Those pictures are very low res, like thumbnails but you can't expand them.
Micromax, I assume. Or is there some other teeny-tiny motor?
Does it corkscrew?
Micromax, I assume. Or is there some other teeny-tiny motor?
Does it corkscrew?
- Joined
- Aug 27, 2011
- Messages
- 11,594
- Reaction score
- 6,215
18mm. Corkscrew flight, net straight trajectory.
Recovery is interesting. The (KEVLAR!) shock cord burned through on first flight (so much for using Kevlar thread as shock cord, going with a bit thicker Kevlar now.) Chute stayed with nose cone. Body and tail descended horizontally, with the fins UP, as you might expect. I expect even if the cord hadn’t broken, likely it would have descended if not horizontally, at least with the one sided fins on the upside.
Obviously not the greatest design for altitude. Certainly an entertaining and safe flyer, and the pattern of recovery is unlikely to break the unusual fin configuration, sort of like my Double Mach Diamond, so recovery is kind of fun to watch too.
Stay tuned, working on SquAir Brake Recovery, coming soon to a forum near you!
Addendum: the corkscrewing makes for a lower altitude flight on these birds, and the asymmetric fins results in a horizontal high drag recovery (I.e., the rocket body and fins contribute significantly to slowing rocket descent) with fins UP so less likely to break, the impact point is the motor casing for minimum diameter birds. So you can get away with a streamer on rocketS you might otherwise use a chute for. So they are nice “small field birds. They do tend to weathercock, however.
Recovery is interesting. The (KEVLAR!) shock cord burned through on first flight (so much for using Kevlar thread as shock cord, going with a bit thicker Kevlar now.) Chute stayed with nose cone. Body and tail descended horizontally, with the fins UP, as you might expect. I expect even if the cord hadn’t broken, likely it would have descended if not horizontally, at least with the one sided fins on the upside.
Obviously not the greatest design for altitude. Certainly an entertaining and safe flyer, and the pattern of recovery is unlikely to break the unusual fin configuration, sort of like my Double Mach Diamond, so recovery is kind of fun to watch too.
Stay tuned, working on SquAir Brake Recovery, coming soon to a forum near you!
Addendum: the corkscrewing makes for a lower altitude flight on these birds, and the asymmetric fins results in a horizontal high drag recovery (I.e., the rocket body and fins contribute significantly to slowing rocket descent) with fins UP so less likely to break, the impact point is the motor casing for minimum diameter birds. So you can get away with a streamer on rocketS you might otherwise use a chute for. So they are nice “small field birds. They do tend to weathercock, however.
Nytrunner
Pop lugs, not drugs
That's the sticky part for me. Corkscrew isn't very defined, and net straight isn't exactly an optimal profile. (adding in your note about weathercock tendencies too)
Does this scale? Is it only safe because they're small crunchable rockets? Would this corkscrew become coning and destruction at higher speeds/power levels? When does the entertaining and safe become "Oh crap, that could have been bad" Are their any guidelines for how much asymmetry is acceptable before things go pear-shaped? And is there any way to predict the behavior analytically beyond a mindsim and push-the-button-and-pray?
I'll admit, the horizontal recovery is cool.
- Joined
- Aug 27, 2011
- Messages
- 11,594
- Reaction score
- 6,215
concur with above. I have probably done 100 scratchers, only two have been midpower, and in one of those I accidentally glued the motor in, so it was one and done (but looks nice dangling from ceiling in my Rocketry build room.)
Inspiration was one of our own, Bruce Levison, who passed away recently from a Covid 19
https://www.rocketryforum.com/threads/we-lost-one-of-our-own-bruce-levison.158724/
I never met him but sounds like he was an impressive individual
He designed the “Cork Screw” for FlisKits, eventually marketed by JonRocket.com. Odd’l Rockets
https://modelrocketbuilding.blogspot.com/2011/03/corkscrew-2-build-backstory.html
https://modelrocketbuilding.blogspot.com/2011/03/corkscrew-2-build-finished.html
I don’t rarely fly above a D, my one G was for 2014 box o parts contest (accidentally glued motor in,
, one and done but looks good dangling from my ceiling, Called it Buzzed Lightyear as liquor bottles were a mandatory part.)Vast majority of my “questionable” models are flown with just me and nobody else around. While I have had some less than nominal flights, only one of my Asymmetric fin models did so, and it was on an A.
Agree, upscaling risking, certainly would run some test models before trying to go big. I am afraid the rotational forces of Cork Screwing alone might tear a mid or high power rocket apart.
Aside from the Cork Screw, which is perfectly named, my favorite is the Squirrel, which flies just like you would expect a good squirrel rocket to Do !
Attachments
Last edited:
I am possessed of a feeling that there needs to be a Plasma Dart III. Need a new take on the plasma core. Most likely multiple plasma engines in pods. Still trying to formulate a plan of some sort.
Oh goodness, I'm very curious to see what this looks like.
Me too.
BBowmaster
Well-Known Member
- Joined
- May 29, 2017
- Messages
- 346
- Reaction score
- 229
Assume the previous Plasma Darts were small craft; create the Plasma Cruiser or mothership.
- Joined
- Aug 27, 2011
- Messages
- 11,594
- Reaction score
- 6,215
Plasma Mother Ship saucer
I was thinking along those lines, but only to a degree. I struggle with design of motherships and the like because I naturally think of them as not being built around a cylindrical airframe. If you look at the whole universe of sci-fi model rocket designs, they mostly lean towards smaller airplane-style craft, or else long skinny starships. There are a few exceptions, but that's the general trend as I see it.
PD1 is mostly what I like to think of as an abstract sci-fi design, not representing anything in particular. PD2 is a small craft. The main thing I'd like to do with PD3 (that will probably not be the actual name) is have multiple engines. It will be suggestive of a larger craft than PD2, but probably not mothership-sized. At least that is my thinking going in. I need to keep the Estes Dark Silver out of my head, lest I inadvertently create a copy (I like that design).
I'm also intrigued by the idea of a long-skinny starship based around plasma core drives (too much time looking at USS Andromeda pics lately), but that's maybe a future project.
Final note: the very first design I posted in this thread, when looking back at it, is really another plasma core variant, although I didn't know it at the time. I've gotta get back to that one at some point.
All this talking is just another way of saying "I don't know what this rocket is going to look like yet."
Nytrunner
Pop lugs, not drugs
Return of the Blackplasma Voyager!
I think the BSV already has design details that could be made to look like plasma cores, if one were inclined to more seriously diverge from the excellent facecard design.
It has also occurred to me (somewhat depressingly) that the first design in this thread has a *lot* in common with the BSV, more than I would like.
lakeroadster
When in doubt... build hell-for-stout!
Charles_McG
Ciderwright
Lots of little plasma cores to imply a much bigger ship than the II.
@BABAR is uniquely skilled at thinking way outside the box, while at the same time making rockets whose fuselages are frequently shaped like a box.
- Joined
- Aug 27, 2011
- Messages
- 11,594
- Reaction score
- 6,215
Thank you!@BABAR is uniquely skilled at thinking way outside the box, while at the same time making rockets whose fuselages are frequently shaped like a box.
BBowmaster
Well-Known Member
- Joined
- May 29, 2017
- Messages
- 346
- Reaction score
- 229
Multiple body tubes ala Sidekick? Say two on each side of the long skinny about half the length. Seems like I’ve seen something similar.
Just trying to spark a muse. Whatever you come up with will be cool.
Just trying to spark a muse. Whatever you come up with will be cool.
All muse-sparking gratefully accepted.
lakeroadster
When in doubt... build hell-for-stout!
@BABAR is uniquely skilled at thinking way outside the box, while at the same time making rockets whose fuselages are frequently shaped like a box.
His air brake rocket is cool beyond words...
That's so true; the most original and unique designs, sand paper nose cones, tubeless air-brake rockets, are boxes so far out of the box.
OK, two things. First, the best way, it seems to me, of making PDIII represent something bigger is to, um, make it bigger. Go BT 70 or 80. It seems like that would be something of a departure for you, but that can be a good thing.
Second, along BBowmaster's line, I had the thought of four BT 70 or 80 tubes in a square or five in a cross, each one with a long core, lile a scaled up PDI Now that's got bigness.
Second, along BBowmaster's line, I had the thought of four BT 70 or 80 tubes in a square or five in a cross, each one with a long core, lile a scaled up PDI Now that's got bigness.
Well this is downright ugly.
Been wanting to try it out, though; one possible approach to outboard plasma cores. Want to try it again with curves instead of sharp angles.
Been wanting to try it out, though; one possible approach to outboard plasma cores. Want to try it again with curves instead of sharp angles.
Nytrunner
Pop lugs, not drugs
Reminds me if alcubuierre without the ring and fancier pods
... and worse in every way.
Hey buds,
Did you see the latest Apogee Newsletter? There's a finishing technique that's really cool. No spoilers, but the first thing I thought of was your designs. Let me know what you think.
https://www.apogeerockets.com/education/downloads/Newsletter525.pdf
Did you see the latest Apogee Newsletter? There's a finishing technique that's really cool. No spoilers, but the first thing I thought of was your designs. Let me know what you think.
https://www.apogeerockets.com/education/downloads/Newsletter525.pdf
Similar threads
