[1.12.x] Cryogenic Engines: Liquid Hydrogen and Methane Rockets! (Jan 22, 2022)

[Nertea]

5 hours ago, cy-one said:

I'm currently doing some comparative stuff with an unpatched, stock nerva (and other stock engines), the cryo-engines and the kerbal atomics engines, to figure out how they fit into the lineup...
I've come to a few conclusions, but would ask for corrections and additions from you guys... I'm not thaaat good with such things, so... that's why I ask XD

Comparing them side-by-side is a bit difficult.

Cryogenic Engines compared to stock engines seem to cost something like 60-70% more and take up about 50% more in tankspace, but also get a bit better TWR in that case.
But I wonder the application of that... It's larger, more expensive (even excluding energy-generation for the tanks), a bit lighter and stronger... But the same result (acceleration and dV) can be achieved with stock chemical engines for less cost and size.

Kerbal Atomic engines compared to an unmodded NERVA are 6 times larger in tankspace, cost double as much as the same stock-solution and weight about the same.
Again, I'm a bit lost for the application when the KA-engines need that much more volume (which you could ignore in space, although x6 is still ludicrous) and cost double as much as the same stock-solution.

To get those "numbers", I built a small benchmark-ship (2.5m pod + Jumbo as payload) and aimed for a TWR of 0.4 to 0.5 with dV of 1900-2000 m/s). Compared where different arrangements of (Sq) NERVAs, (Sq) Swivels, (CE) VL1-Volcanoes and (KA) LV-100 N100 Neptunes.

I think I am missing something... Maybe larger (2.5m, 3.5m?) Cryo Engines / Atomic Motors have a better performance? But on the other hand, so do some stock engines... I'm really confused. I like the look of Nertea's engines, but at the moment (well, see above), I don't see a way of profiting from them...

Your comparisons are kinda weird. You're comparing apples to oranges in a lot of cases there.

Cryo Engines

For a target DV and a constant payload, a cryogenic vehicle should be lighter than a LFO vehicle. It should be somewhat larger and slightly more expensive as a result. This has knock-on effects in that if your vehicle is an upper stage, it should be lighter to lift into orbit, and thus reduce the required LV size.

This is quite easy to show - use an example payload of decent size (sat 20t) and compare a Terrier and a Chelyabinsk. Optimize for the same DV (say 2500 m/s), the mass should drop with the cryo type configuration. This won't work with very small payloads but with a larger one it'll become evident. Optimize for larger DVs and the benefit grows. 

Kerbal Atomics

This is more complicated. KSP set a terrible precedent in basically giving the LV-N all the advantages of a cryogenic fuel (great delta-v) with none of the disadvantages (volume, mass ratio). There were 3 options then when developing KA:

1. Stick with the crazy balance (all KA engines become completely superior to everything)
2. Stick with the crazy balance and artificially degrade KA engines in some way to make them internally balanced
3. Repair the crazy balance at the cost of needing to patch 1 stock engine. 
   1. Patch LV-N Isp to reasonable for a denser fuel (500-600s)
   2. Patch LV-N fuel to LH2

Evidently I chose #3.1. The LF NTRs patch implements 3.2. So if you compare a KA engine to an unmodified LV-N, you're comparing two balance systems that are not compatible. You either have to use all of 3.1 or all of 3.2

You can find a lot more discussion as you page through this thread and KA. 

 

[cy-one]

Cryo: But if the DV and Payloads are the same, why pay more for a larger rocket?

Atomics: Yeah, i noticed that too... KA doesn't seem to work with stock balance, and introduces it's own balance by rebalancing the other competitor.

For me it seems it's more for someone who wants more realism, not necessarily functionality.

[blowfish]

30 minutes ago, cy-one said:

Cryo: But if the DV and Payloads are the same, why pay more for a larger rocket?

Because the rocket you need to lift that rocket can be considerably smaller, and less expensive as a result.  This does raise the question of whether cryogenics are actually useful for launch stages (which is the case in real life as well), although for longer burning sustainer designs it still might be worth it.

[Nertea]

10 minutes ago, cy-one said:

Cryo: But if the DV and Payloads are the same, why pay more for a larger rocket?

If your total second stage/spaceship/whatever mass is lower, you pay less to put it in orbit, as you have a smaller launcher. If you make the same mass of second stage/spaceship, then you will get more performance out of it. It's just a matter of optimizing for whatever variable you're trying to maximize.

I can promise to look at the cost of the engines in the next update though. At least one of them is, from a glance, far too pricy.

11 minutes ago, cy-one said:

Atomics: Yeah, i noticed that too... KA doesn't seem to work with stock balance, and introduces it's own balance by rebalancing the other competitor.

For me it seems it's more for someone who wants more realism, not necessarily functionality.

*shrugs* I don't patch stock things lightly. In all my numerous mods, I've only ever changed two stock parts, the ion engine and the LV-N. The ion engine was patched to create a niche for the entirety of NFP's earlier ion propulsion engines - it changes nothing else. Similarly the LV-N is patched to provide a niche for all of KA's content. 

Such changes have very little to do with realism (when I patch the LV-N, I reduce its mass by 25% and increase its Isp by over 10% to compensate, and all liquid hydrogen tanks have way more fuel in them than they really should), but more with making small adjustments to allow a niche of gameplay to exist. I like making mods that introduce one challenge (new fuel type and its peculiarities) for every problem they solve (great fuel efficiency) to make it more interesting than "replace all your LV-Ns with this engine when you get to X in the tech tree". 

I understand if people don't like it, and that's why I provide the LFO patch for CryoEngines and the LF patch for KerbalAtomics. I'll always listen to critiques and am not opposed to making changes, but it sounds like my paradigms might not be quite what you are looking for. 

[dtoxic]

Sorry if i am posting on the wrong thread

Spoiler

[EXC 02:48:31.719] NullReferenceException: Object reference not set to an instance of an object
    SimpleBoiloff.ModuleCryoTank.GetMaxResourceAmount (System.String nm)
    SimpleBoiloff.ModuleCryoTank.Update ()

Was using the Round (Sphere) tank, tried to switch the content of the tank (fuel switcher B9PartSwitch) then the spamming starts, once i get trough a certain combination, the spamming stops. (cant remember witch fuel/combination is causing this)

https://www.dropbox.com/s/enxkxpi374ixl3n/KSP-CryoTanks.rar?dl=0

[cy-one]

1 hour ago, Nertea said:

If your total second stage/spaceship/whatever mass is lower, you pay less to put it in orbit, as you have a smaller launcher. If you make the same mass of second stage/spaceship, then you will get more performance out of it. It's just a matter of optimizing for whatever variable you're trying to maximize.

I can promise to look at the cost of the engines in the next update though. At least one of them is, from a glance, far too pricy.

*shrugs* I don't patch stock things lightly. In all my numerous mods, I've only ever changed two stock parts, the ion engine and the LV-N. The ion engine was patched to create a niche for the entirety of NFP's earlier ion propulsion engines - it changes nothing else. Similarly the LV-N is patched to provide a niche for all of KA's content. 

Such changes have very little to do with realism (when I patch the LV-N, I reduce its mass by 25% and increase its Isp by over 10% to compensate, and all liquid hydrogen tanks have way more fuel in them than they really should), but more with making small adjustments to allow a niche of gameplay to exist. I like making mods that introduce one challenge (new fuel type and its peculiarities) for every problem they solve (great fuel efficiency) to make it more interesting than "replace all your LV-Ns with this engine when you get to X in the tech tree". 

I understand if people don't like it, and that's why I provide the LFO patch for CryoEngines and the LF patch for KerbalAtomics. I'll always listen to critiques and am not opposed to making changes, but it sounds like my paradigms might not be quite what you are looking for. 

I like your work, please don't missunderstand me there. But yeah, your "goals" often don't fit mine... But besides that, you and RoverDude do some of the most wonderful stuff in this modding community.

When it comes to your engines... Weeell, we might solve to nonproblems (me not liking your mod isn't really a problem... :D) with one go. One thing that caused me to look for a "large advantage" in your engines was the drawback of not being able to produce fuel for it. IIRC, the enriched uranium in the large KA is the same as in Roverdudes stuff... Which can be produced by MKS, so that wasn't a problem. But the whole liquid-hydrogen-thing not being able to be produced via stock or MKS (at least I didn't see anything, but I can be stupid sometimes XD) was a huge drawback....

Soooo, if you could point me in the direction of that LFO/LF-patch (again, I can be stupid sometimes), that would alleviate both problems of mine... I do love your models, and i would like to have them on the butts of my crafts

[Nertea]

41 minutes ago, cy-one said:

When it comes to your engines... Weeell, we might solve to nonproblems (me not liking your mod isn't really a problem... :D) with one go. One thing that caused me to look for a "large advantage" in your engines was the drawback of not being able to produce fuel for it. IIRC, the enriched uranium in the large KA is the same as in Roverdudes stuff... Which can be produced by MKS, so that wasn't a problem. But the whole liquid-hydrogen-thing not being able to be produced via stock or MKS (at least I didn't see anything, but I can be stupid sometimes XD) was a huge drawback....

Already solved that one - both KA and CE patch the stock ISRU to produce LH2 from Ore :). Check it in the VAB - I just had a look and it seems fine. You can also get EnrichedUranium fuelling capabilities from the nuclear reprocessor in NF Electrical.

41 minutes ago, cy-one said:

Soooo, if you could point me in the direction of that LFO/LF-patch (again, I can be stupid sometimes), that would alleviate both problems of mine... I do love your models, and i would like to have them on the butts of my crafts

Extras folder of each download. Should be pretty obvious what does what, I think it's "NTRsUseLF" and "CryoEnginesLFO" or similar. Drop into GameData to use. 

2 hours ago, dtoxic said:

Was using the Round (Sphere) tank, tried to switch the content of the tank (fuel switcher B9PartSwitch) then the spamming starts, once i get trough a certain combination, the spamming stops. (cant remember witch fuel/combination is causing this)

 

This has been logged on github and will be fixed in tomorrow's build. 

Edited October 27, 2016 by Nertea

[cy-one]

Great, now I feel double stupid you glorious stand-up guy

if the EnrichedUranium is "the same" as the MKS/USI-one, I'll use that. I have 80+ mods, no sense in adding one more just for the enriched uranium... and if it's not the same, I'll make a post in the other thread asking for people's help what to change so it is the same EnrichedUranium. ... an Extras folder... I knew there was a drawback in using CKAN over manual install -.-

[cy-one]

10 hours ago, Nertea said:

Extras folder of each download. Should be pretty obvious what does what, I think it's "NTRsUseLF" and "CryoEnginesLFO" or similar. Drop into GameData to use. 

CE has a "CryoEnginesLFO.cfg" in Extras, which I enabled. Just wanted to point out the atomic stuff works differently, and I don't know how.

in the KA-folder, there is no extra when installing via CKAN and there is no "option" via CKAN either (for the CryoEngines, there are options for SurfaceAttach or LFO). And within the /KA/Patched-folder, there's a lot of stuff that only seems to patch other things (like the Squad NERVA and other things).

I'll download KA separately and see if the there's some kind of extra in the normal, non-CKAN-download.

[Nertea]

CKAN installs aren't supported as per the FAQ in the OP. I can assure you that if you download any of the official packages, it'll be there. 

[Nertea]

Reasonably significant bugfix update, 0.4.2.

• Updated CRP to 6.0.1
• Fixed exceptions in VAB when using a ZBO tank for holding only non-cryo fuels
• Fixed incorrect dry masses for ZBO tanks
• Decreased cost and research cost of all engines to be more like 1.15-1.25x their LFO equivalents

[ThreePounds]

11 hours ago, Nertea said:

Reasonably significant bugfix update, 0.4.2.

• Updated CRP to 6.0.1
• Fixed exceptions in VAB when using a ZBO tank for holding only non-cryo fuels
• Fixed incorrect dry masses for ZBO tanks
• Decreased cost and research cost of all engines to be more like 1.15-1.25x their LFO equivalents

Nice! Now I can finally consider them. The steep price made them impractical in my current 40%-funds hard career mode!

[HoveringKiller]

So I guess these provide more thrust but less delta-v than the okidizer boosted Kerbal atomics engines?

[Esquire42]

10 hours ago, HoveringKiller said:

So I guess these provide more thrust but less delta-v than the okidizer boosted Kerbal atomics engines?

Yeah, that's basically it. From greatest dV to least in the Nertea/stock system it goes: electric engines -> nukes -> oxidizer-booster nukes -> cryo -> regular chemical engines. Thrust is this in reverse.

[Stratickus]

Has anyone created a Module Manager patch the adds the cooling effects at the cost of EC that Nertea's Cryo Tanks have?

I just want to add that function/feature to other fuel tanks. I created my own patch and it almost works, but not quite. 

I tried looking through the thread, but there were a bunch of MM patches, so I may have missed it.

Cheers,

[Rodger]

On 07/11/2016 at 2:57 AM, Stratickus said:

Has anyone created a Module Manager patch the adds the cooling effects at the cost of EC that Nertea's Cryo Tanks have?

I just want to add that function/feature to other fuel tanks. I created my own patch and it almost works, but not quite. 

I tried looking through the thread, but there were a bunch of MM patches, so I may have missed it.

Cheers,

I'm trying to do this too, but haven't quite worked it it out yet... I always get two boiloff modules on a tank, one from the vanilla cryotanks patch (with no EC insulation), as well as my own.

@PART[CryoX*]:FOR[VenStockRevamp]:NEEDS[CryoTanks]:Final
{
	!MODULE[ModuleCryoTank]{}
	
	MODULE
	{
		name = ModuleCryoTank
		FuelName = LqdHydrogen
		BoiloffRate = 0.05
		CoolingCost = 0.08
	} 	
}

Also @Nertea, checking configs I saw CryoTanksFuelTankSwitcher.cfg uses "FOR[zzz_CryoTanks]" instead of just CryoTanks. Not sure if its an artifact from testing, or even matters at all, but thought I'd let you know.

[blowfish]

3 hours ago, Rodger said:

Also @Nertea, checking configs I saw CryoTanksFuelTankSwitcher.cfg uses "FOR[zzz_CryoTanks]" instead of just CryoTanks. Not sure if its an artifact from testing, or even matters at all, but thought I'd let you know.

You will see such things pretty commonly in mods that rely heavily on MM patches.  The basic idea is to make sure that the patch runs after nearly every other patch.  So if something is modifying some resource volumes or copying parts with modified parameters this patch will only operate on the final state.  If you need something to happen after this patch is applied, you can always put it as AFTER[zzz_CryoTanks] or anything else with more 'z's (e.g. FOR[zzzz_MyMod] )

Edited November 8, 2016 by blowfish

[Rodger]

Does that mean it would be running after my patch then, even though I had NEEDS[CryoTanks]:Final? Because that would explain what was happening...

[blowfish]

Just now, Rodger said:

Does that mean it would be running after my patch then, even though I had NEEDS[CryoTanks]:Final? Because that would explain what was happening...

No, final patches should run after every named pass.  If you're unsure, you can always check the log to see what order patches are applying in (unless MM is loading from cache, in which case you can delete the cache and reload to see it)

[Stratickus]

On 11/7/2016 at 8:29 PM, Rodger said:

I'm trying to do this too, but haven't quite worked it it out yet... I always get two boiloff modules on a tank, one from the vanilla cryotanks patch (with no EC insulation), as well as my own.

@PART[CryoX*]:FOR[VenStockRevamp]:NEEDS[CryoTanks]:Final
{
	!MODULE[ModuleCryoTank]{}
	
	MODULE
	{
		name = ModuleCryoTank
		FuelName = LqdHydrogen
		BoiloffRate = 0.05
		CoolingCost = 0.08
	} 	
}

 

Ironically enough, I was trying to create the patch for the exact same tanks. Unfortunately, my patch looks extremely similar to yours and I ran into the same problems. I was able to resolve the double boil off modules problem, but couldn't get the insulation module to work. It was there, but it would only say 0.0 EC used and I was unable to edit it.

Cheers,

Edited November 12, 2016 by Stratickus

[Nertea]

You might be seeing an error in initialization if you're using a fuel switcher there. You are missing this line in the module which is used to initialize things if the amount of hydrogen cannot be found. 

FuelTotal = 1500

Where the number is the number of units of fuel present. 

[Rodger]

That doesn't seem to be the problem, it just changes the ec/s rate in the editor parts tray right? When I use the patch I posted, with that FuelTotal added, this is what I get:
http://i.imgur.com/vPPRG7N.png
http://i.imgur.com/bXV0Cqi.png
Two cryo tank modules on the part, one with insulation and one without. So it's getting patched by the patch included with CryoTanks to give it the LH2 fuel switching stuff and no insulation, but I can't patch the same part to ether add insulation to the 'stock' cryotank module, or remove it and replace it with my own patch.

Edited November 15, 2016 by Rodger

[Nertea]

It's still related to initialization: you will need it. This is really a module manager question, not to do with me - both modules appear to be working correctly. However I might suggest just editing the cryo module instead of deleting it?

@MODULE[ModuleCryoTank]
{
	%CoolingCost  = 0.08
}

 

[Rodger]

Well I've tried this:

@PART[CryoXnoseCone]:FOR[VenStockRevamp]:NEEDS[CryoTanks]:Final
{
    @MODULE[ModuleCryoTank]
    {
        %CoolingCost = 0.08
        %FuelTotal = 7146
    }    
}

And still the changes won't take. When I add a new ModuleCryoTank it gets configured properly, but I just cant edit or delete the ModuleCryoTank that gets added by CryoTanks by default.

[Rodger]

@Stratickus I got it working, It seems like it was a MM order thing:

@PART[CryoXnoseCone]:FOR[zzz_CryoTanks]:NEEDS[VenStockRevamp]:Final
{
    @MODULE[ModuleCryoTank]
    {
        %CoolingCost = 0.08
        %FuelTotal = 7146
    }    
}

@PART[CryoXsmall]:FOR[zzz_CryoTanks]:NEEDS[VenStockRevamp]:Final
{
    @MODULE[ModuleCryoTank]
    {
        %CoolingCost = 0.08
        %FuelTotal = 14400
    }    
}

@PART[CryoXmed]:FOR[zzz_CryoTanks]:NEEDS[VenStockRevamp]:Final
{
    @MODULE[ModuleCryoTank]
    {
        %CoolingCost = 0.08
        %FuelTotal = 28800
    }    
}

@PART[CryoXBig]:FOR[zzz_CryoTanks]:NEEDS[VenStockRevamp]:Final
{
    @MODULE[ModuleCryoTank]
    {
        %CoolingCost = 0.08
        %FuelTotal = 48000
    }    
}

@PART[CryoXendButt]:FOR[zzz_CryoTanks]:NEEDS[VenStockRevamp]:Final
{
    @MODULE[ModuleCryoTank]
    {
        %CoolingCost = 0.08
        %FuelTotal = 5652
    }    
}