TiktaalikDreaming

[1.7] [WIP] TD Advanced Propulsion Systems

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I figured I should start a thread for this.

This engine was originally part of my Nexus mod, but a few people thought it should be split out into it's own.  That also gives me the excuse to finally model a solid core nuke engine.

As of now, there's a basically functional Gas Core NTR, with two modes, actively cooled, and regeneratively cooled.  Some details may change before I consider it "release", but at the moment it's enough to enable me to build a nexus in my revamp process.
Blue cards (I just can't call them blue prints, but image thingies in a slightly blue-print style) for the two engines so far.  LH2 then LF

vGko9Lx.jpg

aocug1U.jpg

sftT3ad.jpg

 

 

While it's pre-1.0 it will live only on github; https://github.com/TiktaalikDreaming/TDAPS/releases

It shall get a spacedock entry once at least the first engine is done.

bEBEOTO.jpg

vfk0rYp.png

Kerbal for scale

pSdFD98.png

 

Edited by TiktaalikDreaming
updated 1 of the "blueprint" images for rescaling

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Wow... VERY nice... Good to see you adding moar stand-alone mods to TD Industries... ;)

Quick question tho... can you bake meatloaf with this engine? lol

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4 hours ago, Stone Blue said:

Wow... VERY nice... Good to see you adding moar stand-alone mods to TD Industries... ;)

Quick question tho... can you bake meatloaf with this engine? lol

Probably a bit warm for meatloaf, more a meat patty thing.  0.00001sec on high sort of cooking.  If you like if crispy.  Although, at a distance, from say a hover test, it could probably do some snags... where did that idea come from? :unsure:

1 hour ago, Black034 said:

Nice radiation shield : )  will dl  ! 

The shield is placed to protect all the bits.  The only downside is that the fissionable fuel storage needs to be kept on the safe side to prevent neutrons getting to it, but then is a source of neutrons on the safe side of the shield.  Much milder than the active core or the active neutron emitters, but when doing the shield modelling, they still count.

XKNvmdH.png

The alternative to just having those green things sitting there would be to include a shielding cover or something.  In reality, I don't think they'd be an issue with a suitable propellant tank of huge truck loads of hydrogen in between them and the crew.

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3 hours ago, Drew Kerman said:

/me likes this thread

Seriously what did the Like button ever do to anyone? RIP

The like button is just off while they figure out some technical issues with the forum.  At first I thought it was another daft mobile css interaction.  

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2 hours ago, zer0Kerbal said:

:LIKE:

they could at lease give us a :blink: oops :LIKE: emoji. :P

:LIKE:

yeah, this kinda sucks

:antinormal:

 

More on the rad shield.

OOJ7xAh.png

I added the plume as a volume emission shader cone that tails off, and there's a bit of light from it seen here on the top rim.  The exhaust will be "less" radioactive, both neutron, and gamma, than the core.  Knowing the source is important, which is why each emission source gets it's own colour.  The shadow shield is modelled in as a metallic opaque, which is a bit simplified.  The inside/lower surface should be a gamma reflective heavy metal like tantalum, but the bulk should be layers of substances designed to slow and stop neutrons, typically hydrogen rich substances.  Most of everything else is using a translucent shader with a high roughness, so it refracts and bounces a lot of scatter.  The tungsten tubes I did as opaque though, seeing as that's their purpose.  Not that their opaque to neutrons though.  

Anyway, what I'm getting at, is this is a quick and dirty job, and a realistic one would have separate models for neutrons, gamma rays, fission fragments, alpha particles (for what it's worth) and so on.

Edited by TiktaalikDreaming

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Does it requires anything other than liquid fuel?

Also, what's the thrust and isp relative to the stock nuke?

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8 minutes ago, Space Nerd said:

Does it requires anything other than liquid fuel?

Also, what's the thrust and isp relative to the stock nuke?

At the moment, it runs on liquid hydrogen and two included resources (really just there so you need to think about setting required amounts). It's dual mode, an actively cooled high ISP mode, and a regenerative cooled high thrust mode. I'll need to add a variant to use stock liquid fuel. The ISP will suffer, and thrust will go up. Figures currently are subject to change.

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7 hours ago, Space Nerd said:

Is this standalone or need another mod?

It's original intent was as the second stage engine for my Nexus mod, but the idea of splitting it off is to make it independent, aka standalone

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I just did my calculations for changing the thrust and isp for a kerosene analogue (aka liquid fuel) and the ISP got a bit crappy, but not unworkable.  The thrust is through the roof.  I should also drop the engine mass slightly, as the tubopumps don't need to be as massive (the density is quite different so L/s of pumping is radically down).  Still, I'm not sure an NTR running on something with an average molecular mass in the low 300's is worth doing considering the ISP is now below 300.  I could fudge it for KSP stockness, like the stock NTRs.

Thoughts???  (see https://github.com/TiktaalikDreaming/TDAPS/blob/master/GameData/TDAPS/Parts/OCGC-NTR-LF.cfg)

 

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TWR above two for this thing;

BPqcrIv.png

I may need to assume there's some hydrocarbon disassociation happening at the several thousands of kelvin going on in there.  Hell, in solid cores there's a non-insignificant breaking of H2 into H and H.  I should try and get the ISP above the stock NTR anyway.  Then just excuse it all with waffle.  AKA KSP

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For gameplay reasons, maybe you should give it higher isp and thrust than the stock nuke, so it can be used for interstellar travel.

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15 minutes ago, Space Nerd said:

For gameplay reasons, maybe you should give it higher isp and thrust than the stock nuke, so it can be used for interstellar travel.

It's a open cycle gas core engine, its Isp and thrust is going to be enormous compared to a NERVA anyway.  It's an open nuclear reactor at tens of thousands of Kelvin, so its drawback (other than the enormous weight, justified by its efficiency) is that the exhaust contains radioactive particles with enormous velocities. Despite all this, it's still very impractical for interstellar travel. You need a couple more 0s of Isp to get anywhere outside of the solar system in less than thousands of years.

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So what mods should I use for going to other star systems in stock ksp?

Edit: I just need a super efficient high thrust engine and some ultra long range antennae, not something very complex like interstellar extended.

Edited by Space Nerd

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27 minutes ago, Standecco said:

It's a open cycle gas core engine, its Isp and thrust is going to be enormous compared to a NERVA anyway.  It's an open nuclear reactor at tens of thousands of Kelvin, so its drawback (other than the enormous weight, justified by its efficiency) is that the exhaust contains radioactive particles with enormous velocities. Despite all this, it's still very impractical for interstellar travel. You need a couple more 0s of Isp to get anywhere outside of the solar system in less than thousands of years.

What Standecco said. I've changed it again based on the assumption the average exhaust product molecular mass is around 25, instead of non decomposed kerosene at around 320.

The temperatures are basically a known factor, so that plus the average exhaust molecular mass generates the ISP and thrust. And with hydrogen as a fuel, with essentially highest ISP and lowest thrust, the twr is still fairly reasonable, and the ISP is better than anything this side of ion drives, so beefing up the exhaust mass does result in a bit of a beast. But not an interstellar beast. A different order of magnitude is needed for that.

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44 minutes ago, Space Nerd said:

So what mods should I use for going to other star systems in stock ksp?

Edit: I just need a super efficient high thrust engine and some ultra long range antennae, not something very complex like interstellar extended.

There's no other star systems in stock ksp. Or mods to help you get there. At least for what most people mean by stock.

But....There's a few mods with silly engines. My addition to the collection

But there's very little physically plausible, very fast, very efficient engine concepts that pass even cursory scrutiny. For plausible interstellar travel, you'll need a seriously improved time warp.

Realistically, our best current bet using fully known technology would be Hall effect upon drives because efficiency is much more important than thrust. And the trip would take a very very long time.

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Oops, I mean extra star systems mods(like galaxies unbound by @StarCrusher96), and by mods I mean something like a nuclear fusion engine to help me get there..

And I somehow deleted my last post.(I mean stock size ksp with mods in that post)

 

Edited by Space Nerd

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7 hours ago, Space Nerd said:

Oops, I mean extra star systems mods(like galaxies unbound by @StarCrusher96), and by mods I mean something like a nuclear fusion engine to help me get there..

And I somehow deleted my last post.(I mean stock size ksp with mods in that post)

 

I think everyone could see what you meant, I was just giving you grief over the word "stock".  Stock size is a meaningful distinction a lot of the time though.

With interstellar travel, the planet size makes less of a difference of course, as the distances get so much larger.  That said, a lot of those multi-star-system mods involve less than realistic distances between stars, or at least less than we're used to out here in the outer bits of our unfashionable arm of our spiral galaxy.  But you will end up needing something to traverse distances of the order of a light year through to many.  And the best we've got as far as plausible ideas is probably things like Zubrin's nuclear salt water drive in full weapons grade load.  And that concept is a pretty scary beast, even though "salt water drive" sounds fairly innocuous. But at best you'd be accelerating to 1-2%C then flipping and slowing down.  Still talking centuries to alpha-centauri.  :/  As I said, much much better time warp.

You can get similar ISP values out of the plausible fusion concepts like inertial confinement, but the TWR goes way down.  The problem with fusion (as far as humans have so far figured out how to fusion, anyway) is that you need big things to make a tiny bit work.  So, huge banks of lasers, or huge arrays of magnets, or ...  Lots of mass, one way or the other.  So, you end up with a huge craft, because your engine needs to be 1000 tonnes or so, but you don't want 5% fuel, you want 90% fuel, so now your craft is enormous.  And the TWR is starting to look a bit ION ish.  OK, lots better than ION, but it's not going to be doing much in the way of artificial gravity with the engines.

 

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I have better time warp :-)

maybe after I finished stock system + opm and installed extra solar systems mod, I will try to build something with your mod.

On 9/17/2019 at 7:52 PM, TiktaalikDreaming said:

At the moment, it runs on liquid hydrogen and two included resources (really just there so you need to think about setting required amounts). It's dual mode, an actively cooled high ISP mode, and a regenerative cooled high thrust mode. I'll need to add a variant to use stock liquid fuel. The ISP will suffer, and thrust will go up. Figures currently are subject to change.

So this mod includes liquid hydrogen tanks?

Edited by Space Nerd

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8 hours ago, Space Nerd said:

I have better time warp :-)

maybe after I finished stock system + opm and installed extra solar systems mod, I will try to build something with your mod.

So this mod includes liquid hydrogen tanks?

There's now a second version (updated model in development) using stock LiquidFuel.  As mentioned above, I messed around with the exhaust product molecular mass to make it a sane choice, with vacuum ISP at around the 1000, and around 12MN thrust.  I took out the actively cooled mode from the dual mode for it, as that's the "we want to maximize ISP" option, which you're clearly not doing when running kerosene through it.  And dropped the mass due to less complexity, and lessened the tungsten use, as hydrocarbons should be partly opaque to gamma.

Versions 0.4 onwards will have the second engine.  

I'm tweaking a few things on the model.  I'm shrinking parts of the turbo-pump assemblies, adding some colours to some spots to differentiate things, and removing the helium lines for active cooling.  

Liquid Hydrogen;

ACPE4cU.png

Liquid Fuel;

gjozAFW.png

 

 

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OK, the Liquid Fuel version now has it's own plume and some of the texture switched around, smaller pumps, etc, as mentioned above.

xwkgYVA.png?1

https://github.com/TiktaalikDreaming/TDAPS/releases/tag/0.4.190921

(Edit: Note about test craft: The craft shown is mostly stock.  I used a Tundra Exploration capsule (not shown) to get something 5m wide and larger RCS, and Making History tankage with the oxidizer removed.)

 

Edited by TiktaalikDreaming

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