Nertea

[1.8.x] Cryogenic Engines: High Isp chemical rockets! (Updated Nov 6)

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Small update to 0.1.5

  • Fixed LFO patch targeting wrong 1.25m engines
  • Fixed tank patch targeting LF/O/MP tanks, which it shouldn't have
  • Updated to the latest version of InterstellarFuelSwitch

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Like everyone else I am astonished how quickly this mod became important to me. It was the first mod i downloaded with the new update and I was instantly hooked. IDK but either way bravo.

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Here is a MM .cfg to make the tanks from Procedural Parts compatible with these engines. No guarantees on its accuracy, as I'm pretty much guessing at what I'm doing. I calibrated this against the Rockomax X200-16 tank and it should work. I hope someone who knows what they are doing can see this and fix my screw-ups!

@PART:FINAL[proceduralTankLiquid]
{
@MODULE[TankContentSwitcher]
{
TANK_TYPE_OPTION
{
name = Hydrolox
dryDensity = 0.1196
RESOURCE
{
name = LqdHydrogen
unitsPerKL = 956.118
}
RESOURCE
{
name = Oxidizer
unitsPerKL = 95.6118
}
}

}
}

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is there a download link somewhere to a version without Interstellar Fuel Switch? it seems to completely break Tweakscale.

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You can always just remove the InterstellarFuelSwitch folder and the CryoEnginesFuelTanks.cfg (in CryoEngines/Patches) file from the download provided. It's really not worth me putting up a separate DL. FreeThinker told me that it's supposed to work with TweakScale though.

Also, this is up on CurseForge now, if anyone has a pressing need to use that site.

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Fantastic engines

A little post just to signal a typo in the optionals CFGs (CryoEnginesLFO/CryoEnginesLFO.cfg)

line 97 : @PART[cryoengine-375-1] not @PART[cryoEngine-375-1]

Thanks for these nice parts...

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Installed these engines and when they showed up in the VAB on my save I immdietly wondered what incentive I'd ever have of using the normal ones again... then I saw the height of these things O_o

I love how you've managed to balance these using something else than isp/thrust/twr! Keep up the good work Nertea, you rock!

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Seems like a great mod, but I can't switch the contents of the fuel tanks. And I don't know how to install the LFO version.

- - - Updated - - -

Wait hold on, the LFO config says

// Sets cryoEngines to use lFO at 20 lower Isp

But then in the confiq it says

@PART[cryoengine-125-1]

{

@MODULE[ModuleEnginesFX]

{

!atmosphereCurve {}

atmosphereCurve

{

key = 0 390

key = 1 340

key = 4 0.001

}

@PROPELLANT[LqdHydrogen]

{

@name = LiquidFuel

@ratio = 0.9

}

@PROPELLANT[Oxidizer]

{

@ratio = 1.1

}

}

}

Am we meant to change that?

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is there a download link somewhere to a version without Interstellar Fuel Switch? it seems to completely break Tweakscale.

I'd double check your setup and maybe try a re-install of the various mods (IFS, TweakScale, CryoEngines) - I'm using all 3 and haven't had a single issue with any of them so far. Has worked great actually and I refuse to give these engines up ever again. :D

On a side note - GREAT JOB AGAIN Nertea!!

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Seems like a great mod, but I can't switch the contents of the fuel tanks. And I don't know how to install the LFO version.

- - - Updated - - -

Wait hold on, the LFO config says

// Sets cryoEngines to use lFO at 20 lower Isp

But then in the confiq it says

@PART[cryoengine-125-1]

{

@MODULE[ModuleEnginesFX]

{

!atmosphereCurve {}

atmosphereCurve

{

key = 0 390

key = 1 340

key = 4 0.001

}

@PROPELLANT[LqdHydrogen]

{

@name = LiquidFuel

@ratio = 0.9

}

@PROPELLANT[Oxidizer]

{

@ratio = 1.1

}

}

}

Am we meant to change that?

Yes, LFO engines have lower Isp in RealLife, also LFO tanks weigh less than LH2/Ox tanks (assuming equal mass of fuel in both tanks 12.5% of fuel mass vs 25% fuel mass if I remember correctly)

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Well higher ISP is balanced by heavier tanks (for every 100ton of LOX you carry about 12.5t of structural 'tank' weight, but for LH2/Ox this number is much higher: 22t).

So in the end gains aren't that high; with typical cargo you have like 10-12% gain of dV over stock chemical engines (and it's still much lower than LV-N). Plus you can't refuel those engines unlike stock ones so I wouldn't call them overpowered. Just my opinion.

Well, I don't know but they certainly seem to be.

My simple test of making rocket consisting from MK1 pod, tanks and an engine, and looked for a starting ASL TWR of 1.3.

With the "swievel" got 13.5 ton craft with 3500dv ASL/4170dv VAC

With the VL1 got 20ton craft with 4300dv ASL/4980 VAC. (Or 13.5 ton with 3800 dv ASL.)

So in this particular case, there is 20% boost. With some creative staging superiority becomes even more noticeable.

Problem is not so much the ISP and trust of these engines (which are rather realistic), problem is how much the isp of stock engines were slashed.

IMO trust should be reduced little.

Otherwise - beautiful engines.

And hilarious naming, granted that Russians historically avoid cryogenic fuels.

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Yes, LFO engines have lower Isp in RealLife, also LFO tanks weigh less than LH2/Ox tanks (assuming equal mass of fuel in both tanks 12.5% of fuel mass vs 25% fuel mass if I remember correctly)

Umm, that's not my problem. I want them to burn LFO and not LqdHydrogen. But I don't know how and this confiq didn't do anything.

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Is it just me, or are these cryogenic rockets/stages just more expensive and heavier than their LFO counterparts? Especially Skipper, Mainsail, Rhino and Mammoth just seem to be much more efficient and cheaper.

I mean, they look awesome and that's already reason to use them, but they seem kinda weak. Especially the tunguska feels a bit out of place: It's to heavy to be an efficient long range low t/w engine (not to mention nukes), and otherwise the volcano just beats it in every regard. On the other hand there is a bit of a lack of a lighter 2.5m mid-stage engine that can compete with the skipper. Said volcano looks like the most efficient engine of the pack, but according to kerbal engineer ships with it are on the efficiency level of a poodle. And the bigger KSP engines only get better after the poodle.

Tbh, I was a bit afraid the pack could be op, but it seems more like the contrary. :)

Edited by Temeter

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*shrugs* balance is still evolving, but I found performance to be much better, accounting for the large fuel volume (about 1.75x).

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Is it just me, or are these cryogenic rockets/stages just more expensive and heavier than their LFO counterparts? Especially Skipper, Mainsail, Rhino and Mammoth just seem to be much more efficient and cheaper.

I mean, they look awesome and that's already reason to use them, but they seem kinda weak. Especially the tunguska feels a bit out of place: It's to heavy to be an efficient long range low t/w engine (not to mention nukes), and otherwise the volcano just beats it in every regard. On the other hand there is a bit of a lack of a lighter 2.5m mid-stage engine that can compete with the skipper. Said volcano looks like the most efficient engine of the pack, but according to kerbal engineer ships with it are on the efficiency level of a poodle. And the bigger KSP engines only get better after the poodle.

Tbh, I was a bit afraid the pack could be op, but it seems more like the contrary. :)

last time I've checked vac cryo engines were good since they provided about 4-16% more dV with same mass of engines/tanks (they were superior especially with heavy payloads).

Atmo cryo engines are problematic due to still too low TWR (either you loose dV because you have less fuel mass or you loose dV because your TWR is lower than stock atmo lifters), however maybe now with 'soupier' atmosphere in 1.02 the difference won't be as dramatic as in 1.0 :/

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For me the t/w seems to be the deciding factor. Yeah, Cryo Engines can bring a specific weight of fuel further. It's just that Skipper/Mainsail are not only lighter, but also carry more weight with less engine tonnage. Attempts at sustaining the T/W automatically puts conventional engines ahead.

That said, I find it hard to judge what the superior atmo ISP of Odin, Mars and Volcano does.

edit: And yeah, there seems to be a weight advantage for cry engines for superheavy lifters. Tried one and got 1.7kt compared to 2.2kt. As a whole it was slightly more expensive.

edit2: Oooooooooh, making the upper stage cry and lower lfo actually saves a lot of money. I assumed so, needed heavy freight, tho. I love experimenting.

Edited by Temeter

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*shrugs* balance is still evolving, but I found performance to be much better, accounting for the large fuel volume (about 1.75x).

How do I install the LFO version?

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How do I install the LFO version?

Put the patch in the GameData directory. there might be a tyoe in one of the patches, check all the engines.

For me the t/w seems to be the deciding factor. Yeah, Cryo Engines can bring a specific weight of fuel further. It's just that Skipper/Mainsail are not only lighter, but also carry more weight with less engine tonnage. Attempts at sustaining the T/W automatically puts conventional engines ahead.

That said, I find it hard to judge what the superior atmo ISP of Odin, Mars and Volcano does.

edit: And yeah, there seems to be a weight advantage for cry engines for superheavy lifters. Tried one and got 1.7kt compared to 2.2kt. As a whole it was slightly more expensive.

edit2: Oooooooooh, making the upper stage cry and lower lfo actually saves a lot of money. I assumed so, needed heavy freight, tho. I love experimenting.

Well, you're just describing all sorts of real rockets, like the Saturn V :P! Excellent. Lots of hydrolox first stage rockets bundle SRBs for the TWR kick.

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Put the patch in the GameData directory. there might be a tyoe in one of the patches, check all the engines.

Well, you're just describing all sorts of real rockets, like the Saturn V :P! Excellent. Lots of hydrolox first stage rockets bundle SRBs for the TWR kick.

K, I'll try that.

- - - Updated - - -

I did that and fixed the typos but it didn't change anything.

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Well, you're just describing all sorts of real rockets, like the Saturn V :P! Excellent. Lots of hydrolox first stage rockets bundle SRBs for the TWR kick.

Yeah, I remembered some ariane concept having a 2nd cryo-stage and wanted to try it. Ofc also makes sense putting low t/w high efficiency engines at the later stages. Kinda what lead me to think that the pack kinda misses a 2.5m 500 to 600kn skipper-style engine. Two volcanos do at good enough job, but they seem more like low stage lifter engines.

Thanks for the tip with SRBs, somehow typical that I first think about various combinations of different engine types and than completely forget the most obvious solution. An Odin with some SRBs is surprisingly efficient. Just a tiny bit better than LFO's, but there are some interesting applications to try.

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These are cool. Ever since NFP was first released I've wanted a lander engine capable of using NFP's LH resource. This definitely fills that.

One idea for a part I'd love to see added here is a radial version of these engines. Way back when in the HOME pack Bobcat had a radial Aerospike that was absolutely perfect for small landers. I build a lot of my landers dropship style so they have a very low vertical profile which means a full length engine can be hard to fit without part clippage.

In any case, with the update to NFP rolling along, eventually I think I'll find it really interesting to try building some hybrid long range landers that use both NFP's super efficent engines for most stuff and these for landing / takeoff.

Edited by Immashift

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About the LFO config found in the extras folder, do I just copy the .cfg into all the engine folders or do I place them somewhere else? I am unclear on this

Edit:

When I have the LFO config and the Cryoengines folder in my GameData folder the game doesn't fully load but when I take them out it loads properly. Any suggestions?

Edited by Jumpyyoza

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It occurred to me that the resource system we now have in stock does not generate Hydrogen, so I have written an MM config to allow it to do so.

It produces standalone LH2, and LH2+Ox in what should be the correct ratio to fill tanks evenly.


@PART[ISRU]
{
MODULE
{
name = ModuleResourceConverter
ConverterName = LH2+Ox
StartActionName = Start ISRU [LH2+Ox]
StopActionName = Stop ISRU [LH2+Ox]
AutoShutdown = false
GeneratesHeat = false
UseSpecialistBonus = true
SpecialistEfficiencyFactor = 0.2
SpecialistBonusBase = 0.05
Specialty = Engineer
EfficiencyBonus = 1



INPUT_RESOURCE
{
ResourceName = Ore
Ratio = 0.5
FlowMode = STAGE_PRIORITY_FLOW
}
INPUT_RESOURCE
{
ResourceName = ElectricCharge
Ratio = 30
}
OUTPUT_RESOURCE
{
ResourceName = LqdHydrogen
Ratio = 1.0
DumpExcess = false
FlowMode = STAGE_PRIORITY_FLOW
}
OUTPUT_RESOURCE
{
ResourceName = Oxidizer
Ratio = 0.1
DumpExcess = false
FlowMode = STAGE_PRIORITY_FLOW
}
}
MODULE
{
name = ModuleResourceConverter
ConverterName = LH2
StartActionName = Start ISRU [LH2]
StopActionName = Stop ISRU [LH2]
AutoShutdown = false
GeneratesHeat = false
UseSpecialistBonus = true
SpecialistEfficiencyFactor = 0.2
SpecialistBonusBase = 0.05
Specialty = Engineer
EfficiencyBonus = 1



INPUT_RESOURCE
{
ResourceName = Ore
Ratio = 0.5
FlowMode = STAGE_PRIORITY_FLOW
}
INPUT_RESOURCE
{
ResourceName = ElectricCharge
Ratio = 30
}
OUTPUT_RESOURCE
{
ResourceName = LqdHydrogen
Ratio = 1.1
DumpExcess = false
FlowMode = STAGE_PRIORITY_FLOW
}
}
}

I did test it, and it is much better than my prior attempts at MM configs in that it works, but feel free to correct me on the fuel ratios, etc.

Oh, and this should be up to date with the changes to heat behavior as of 1.0.2.

Edited by Starbuckminsterfullerton

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Hello Nertea!

I really love your mods and I have decided to make a separate install of KSP next to my mostly stock install to play only with your mods because they fit thematically so well together. I love those LH2/LO2-Engines, they are awesome!

I have yet to see if the density of LH2 is believable in the tanks, but even if it isn't, there sure is a way for me to adjust that to my liking.

But there is one thing that I find really odd. It's the presentation of the exhaust stream of the engines. This slow-motion effect looks cool when you turn the engine or throttle it and the exhaust "lags behind". But it isn't really believable to anyone remotely familiar with how engines work. You even show us those amazingly pretty shock diamonds in the exhaust stream (whether they should occur in a vacuum or not is an entirely different story) which make my heart jump with joy! However, as the high Isp of these engines indicates, the exhaust should me moving several km/s and therefore should update instantly as you turn or throttle the engine. Could you consider changing the system to a more static approach? It'll look so much better for the slightly trained eye!

Thank you and keep up your excellent work!

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Three_Pounds is right about the exhaust. HotRockets encountered exactly the same problem in the early stages of it's development, so there should be a solution buried somewhere in that thread.

Edit: sounds like Nazari just upped the speed/decay rate. Before that it did this:

23gVMtI.gif

Discussion starts around pg. 4 for anyone else looking.

Edited by Starbuckminsterfullerton

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