Neil_W's half-baked design thread

[neil_w]

That's a cool one, rings and pods and plasma core

Yes, all brand-new design elements I thought I'd explore! Not sure whether I'm gonna keep playing with this one.

This would be an absolute nightmare to build and paint.

 

[kuririn]

That's a cool one, rings and pods and plasma core

Rings and pods and plasma core
And flowing lines both near and fore
I never imagined this before
I've looked at clouds that way......
(My apologies to Joni Mitchell).

 

[neil_w]

Rings and pods and plasma core
And flowing lines both near and fore
I never imagined this before
I've looked at clouds that way......
(My apologies to Joni Mitchell).

 

[mbeels]

For rockets like this, I'm all for the fantastical, futuristic, far-fetched, and fabulous looking designs. I like both the cylindrical and spherical plasma cores, no need to be bound by reality! But, if you wanted to add another geometric shape to your design pool, what about a toroid? It would fit current ideas for takomak toroidal plasma containment.

 

[boatgeek]

I like the rings and plasma core, but I think the pods are a little over the top. Maybe no pods and swoopier fins like the Cthulhu plasma ball one?

 

[jqavins]

That's definitely got its appeal. It's not... quite... something?

 

[neil_w]

I have a nagging desire to build a two-stage rocket where the booster is essentially a saucer. Theoretically it would need to stage at 50 ft/sec and it'd be good.

I'm thinking an overpowered 24mm saucer booster to an 18mm sustainer. The booster would make a lot of noise (well, relatively speaking) but not go very far, then it would stage pretty low. The booster would be easy to recover.

I don't know if this would be as good in practice as it sounds in my head. Or if it would work at all. Hard to sim the full stack unless I use only components that OR understands; probably possible to get an approximation. Would need to stage at at least 50 fps (preferably with some margin) to do so safely, right?

Trying to think of a way to design it for extra fun-ness, which would probably be focused on the booster. Nothing concrete yet. Ideas welcome.

Hoping a really "different" sort of design will get my design mojo going again, feeling sort of flat lately.

 

[Charles_McG]

Spinning saucer?

 

[neil_w]

Spinning saucer?

Could be. That would seem to improve stability at staging a bit, and maybe make it more interesting. In general it would be fun for the booster to do something interesting when it ejects, I think; spinning back to earth would qualify.

 

[kuririn]

Clustered girandola with sustainer stage?
Or two stage girandola?

 

[BABAR]

I have a nagging desire to build a two-stage rocket where the booster is essentially a saucer. Theoretically it would need to stage at 50 ft/sec and it'd be good.

I'm thinking an overpowered 24mm saucer booster to an 18mm sustainer. The booster would make a lot of noise (well, relatively speaking) but not go very far, then it would stage pretty low. The booster would be easy to recover.

I don't know if this would be as good in practice as it sounds in my head. Or if it would work at all. Hard to sim the full stack unless I use only components that OR understands; probably possible to get an approximation. Would need to stage at at least 50 fps (preferably with some margin) to do so safely, right?

Trying to think of a way to design it for extra fun-ness, which would probably be focused on the booster. Nothing concrete yet. Ideas welcome.

Hoping a really "different" sort of design will get my design mojo going again, feeling sort of flat lately.

I think it has been done. Not sure of motor choices, but was a saucer to a 3FNC, maybe a Snitch to an Alpha or possibly something lighter. I believe I saw it on RocketReviews (maybe @jadebox can find it, I did several searches but can’t find it now, could have sworn it was Chan Stevens but can’t find it on any of his pages.)

Do you have electronics that will give you flight info, not just an altimeter but also velocity? Poor mans version might be a stopwatch and altimeter, at least that would give you AVERAGE velocity. Make it a relatively small saucer with a relatively big 24mm motor mount, should help you get up to speed faster. This puppy is however going to weathercock like made, most likely.

I am thinking build a test saucer, put a mass equivalent to the sustainer directly at the “nose” equivalent region of the saucer, launch it and check velocity.

With a little finess, you may be able to “nest” the tail of the 18mm sustainer motor in the forward bore of the 24 mm motor. OTOH if it is too tight the 24 mm might CATO. I like 18 mm A motors for first flights for sustainers if you gap stage, they have a big nozzle bore, so easier to light, and low power, so if there is fecal turbine interaction at least you have less “gas in the tank” for a non vertical trajectory. A10-3T with and adapter is also good, plus lower mass so win-win.

If you feel like branching out, also consider gliders, Helis, air Brakes, horizontal spin recovery, of backslider recoveries.

https://www.apogeerockets.com/education/downloads/Newsletter447.pdf

 

[neil_w]

This puppy is however going to weathercock like made, most likely.

Will it? Saucers typically fly arrow straight in my experience if sufficiently powered. That should put the sustainer on a straight track if it's going fast enough (and spin should help as well).

With a little finess, you may be able to “nest” the tail of the 18mm sustainer motor in the forward bore of the 24 mm motor.

I believe that is a standard practice for 24mm -> 18mm staging, or 18mm -> 13mm staging.

Still unsure how to make this *interesting*, not just novel (and maybe not even novel).

 

[Senior Space Cadet]

Thought about turning the saucers ninety degrees, possibly using one big saucer as a wing or fins?
Or go for the flying wing look.
I don' have your skill with Open Rocket or I'd show you what I'm thinking.

 

[boatgeek]

What if you did a spin stabilized sustainer with no fins on top of a spinning booster like a Quinstar? You’d need an understanding RSO and launch from far pads but it would be pretty entertaining. Worst case if it’s unstable it skywrites and falls to earth from 50-100 feet. Definitely a use case for a short burn sustainer motor on the first flight.

 

[BABAR]

Will it? Saucers typically fly arrow straight in my experience if sufficiently powered. That should put the sustainer on a straight track if it's going fast enough (and spin should help as well).

I believe that is a standard practice for 24mm -> 18mm staging, or 18mm -> 13mm staging.

Still unsure how to make this *interesting*, not just novel (and maybe not even novel).

I haven’t done direct staging in long time, so I may be out of touch. Pretty much 15” is my minimum gap, mainly because my boosters are usually 18” long.

I suspect most of the saucers I have seen were underpowered.

Apogee has an interesting new rocket

https://www.apogeerockets.com/Rocket-Kits/Skill-Level-3-Model-Rocket-Kits/Slo-Mo
Big angled canted fins with holes for drag. Something of this sort might make a good sustainer if you are concerned about velocity at staging.

 

[neil_w]

One, obvious answer: booster looks like a Porta-pad, with extra drag-enhancers and spin-inducers. Sustainer launches from the pad in mid-air. I've seen goof rockets that look like a Porta-pad with a rocket on them, but I don't think I've seen one implemented as a 2-stager. It's probably out there though.

 

[Charles_McG]

Upon further reflection, I don’t think you want a spinning booster. One, if it really starts spinning on the rod, it can have a nasty whip off the top. Second, you’d want to do a double check of the tip tangential velocity of the sustainer fins - it’s going to act like a cross wind and you don’t want to stall them. And predicting the RPM will be challenging, I think.

I think something like a Satellite Killer with a staged Kinetic Kill Vehicle in the center would be cool.

Last thought (for now), I wouldn’t get hung up on the vertical velocity. 50fps for a speed off the rod is a fine idea for a rocket launched from said rod. It means you’re good to go up to a 12fps crosswind. But once in the air, that stack is going to rapidly match the crosswind and the experienced crosswind will be zero. Like in a hot air balloon. Until you hit a wind shear layer, at least. The sustainer is going to think it’s almost dead calm. If it’s straight up at staging, you’re good.

 

[neil_w]

I think something like a Satellite Killer with a staged Kinetic Kill Vehicle in the center would be cool.

Are you referring to any specific Kinetic Kill Vehicle design, or just the general concept?

 

[Charles_McG]

Are you referring to any specific Kinetic Kill Vehicle design, or just the general concept?

Just the concept. But my fingers capitalized it.

 

[Charles_McG]

You know, if you used the Satellite Killer as a base concept, you could put a toroidal bead around each of the ‘barrels’ and do your plasma core thing, so it would be like 5 tokamaks.

 

[BABAR]

@Daddyisabar did a flying pad that actually I think would easily mod to do what you would like.

 

[neil_w]

You know, if you used the Satellite Killer as a base concept, you could put a toroidal bead around each of the ‘barrels’ and do your plasma core thing, so it would be like 5 tokamaks.

Mmm, Plasma Saucer. Now there's a thought. I like the idea of the sustainer launching from some sort of open frame tube-like structure on the booster. Would look cool on the ground at least.

 

[jqavins]

 

[jqavins]

I have a nagging desire to build a two-stage rocket where the booster is essentially a saucer. Theoretically it would need to stage at 50 ft/sec and it'd be good.

Yeah, yeah. Talk, talk, talk. We need some pictures. If you don't get some pictures up here yesterday, I'm gonna have to do it myself.

OK, I know you said saucer, but a spool was a lot easier to put together in RS. First the sustainer.




Then the stack.


There's a way to trick RS into simulating base drag. It did'nt work this time. It computed a nice high static margin, but sims would crash pretty much instantly.

I won't sweat that part because, Neil, this is your thread so it's your problem, if you want it.

 

[neil_w]

I won't have time to actually put anything together before vacation. This is a backburner project.

 

[BABAR]

Yeah, yeah. Talk, talk, talk. We need some pictures. If you don't get some pictures up here yesterday, I'm gonna have to do it myself.

OK, I know you said saucer, but a spool was a lot easier to put together in RS. First the sustainer.
View attachment 429214
View attachment 429215
View attachment 429216

Then the stack.
View attachment 429206
View attachment 429213
There's a way to trick RS into simulating base drag. It did'nt work this time. It computed a nice high static margin, but sims would crash pretty much instantly.

I won't sweat that part because, Neil, this is your thread so it's your problem, if you want it.

Again, outside the box.

Put a dowel launch rod on top of the saucer (the Estes MIRV, a miserably underpowered rocket, does have this.). Assuming the stack is vertical at staging, it will let the sustainer get a bit more up to speed AND will allow the fins perhaps to clear the “dead air” induced by the saucer structure underneath it.

 

[afadeev]

One, obvious answer: booster looks like a Porta-pad, with extra drag-enhancers and spin-inducers. Sustainer launches from the pad in mid-air.

Your challenge will be accelerating the two-stage beasty, including saucer / Porta-pad, to a 50+ft/sec (probably more like 80+ ft/sec to account for gliding until booster separation), so that the second stage will be aerodynamically stable when it lights up. That wont be easy with the massive aero-drag from the saucer booster!

Alternatively, put a GPS tracker into the sustainer, and let it rip in cruise-missle mode?

 

[neil_w]

I have no idea how fast a saucer normally can go; will need to see if I can coax a sim to give me a number. Intuitively, 50 ft/s seems achievable to me with a light but draggy stack and a D12 in the booster. But I need to run some numbers.

 

[lakeroadster]

Why not make the saucer more like a space station? Basically more like a wheel with spokes instead of a saucer. Much less "draggy" but still visually awesome. Maybe even a station that's still under construction?

 

[jqavins]

Would that give you base drag you need for stability?