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


Nertea

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KSP 1.12.x

Cryogenic Engines [2.0.6] 
Last Updated January 22, 2022

iOlGMTk.png

This modest part pack is designed to provide some new rocket engines that run either Liquid Hydrogen and Oxidizer or Liquid Methane and Oxidizer.

Liquid Hydrogen Engines

There are nine models provided, two in each of the 1.25, 1.875, 2.5 and 3.75m sizes and one in the 0.625,. These engines have better fuel efficiency than the KSP stock engines, up to 460s of Isp, but beware! They're more expensive and produce less thrust per unit weight. In addition, liquid hydrogen is less dense than liquid fuel, so for the same Delta-V, you will need more tank volume.

Liquid Methane Engines

There are ten  models provided, two in each of the 0.625, 1.25, 1.875, 2.5 and 3.75m sizes. These engines sit between the Liquid Hydrogen and Liquid Fuel options in terms of efficiency, and don't have as much of a tank volume penalty. 

To store your new fuels, I've provided ModuleManager/B9PartSwitch configs that allow you to change the contents of stock tanks between LF/O, LH2/O, LCH4/O, LF, O,  LH2 and LCH4. These should work with most mod tanks, but no promises. However, Liquid Hydrogen is very temperamental and without the proper storage it will slowly evaporate ("boil off"). You can activate cooling on all added tanks for a modest cost in Electric Charge, but this is inefficient. Therefore, I provide special cryogenic tanks bundled with the mod which have insulation to reduce the cost of cooling the tanks. Liquid Methane will also boil off, but more slowly than Liquid Hydrogen. 

This mod is designed to synergize well with Kerbal Atomics, and with the various Near Future Technologies mods I make. It is also fully integrated into the Community Tech Tree.

Full Screenshot Gallery

Frequently Asked Questions

Q: Will you add feature/part xxx?
A: I am now retired from KSP1 modding and will only be providing bugfixes. 

Q: Oxidizer isn't LOX, it's something else!
A: You are completely free to do whatever you like and change it :wink:

Q: How do I stop the engines from using LH2/O and use LF/O instead?
A: Install the CryoEnginesLFO patch in the Extras folder. 

Dependencies (Required and Bundled)

  • Module Manager 
  • B9 Part Switch
  • Community Resource Pack
  • Cryo Tanks
  • Deployable Engines
  • Dynamic Battery Storage

Licensing

  • All code and cfgs are distributed under the MIT License
  • All art assets (textures, models, animations) are distributed under an All Rights Reserved License.
  • All bundled mods are distributed under their own licenses.

Download
Mirrors

Primary (SpaceDock)
Secondary (CurseForge)

Tertiary (GitHub)

Issue Tracking and Source

Special Thanks 

A big hand to Fraz86, who basically wrote the configs for fuel switching and balancing LH2 tanks :D.

If you appreciate this project, please consider contributing to my caffeine addiction! I really appreciate it, and also helps justify this time sink to my wife :wink:, which results directly in more models. btn_donate_SM.gif

Edited by Nertea
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Yay y'all like it!

Could boiloff be added as an option, to further enhance the realism?

That's RealFuels' domain, when compatibility is added for that, you can use it for boiloff.

I hate to ask such a question because it almost seems insulting to your work and original intent for these engines, but would you consider writing an optional config for using standard LF/O?

It's in the Future Plans above.

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Yay y'all like it!

It's in the Future Plans above.

This "patch" should be the standard, IMO - it would allow to use these engines even without MM. All other features (LH2, firespitter and such) should be optional MM patches.

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lf/o IS the standard, and OP wanted to do something different from that. That's why the lf/o configs will be MM patches.

That's exactly what I meant in my post. LF\O should be in part configs, and LH2 should be added as an optional patch.

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I really like how the heavy 3.75m engine resembles an RS-68 used on a Delta IV Heavy, kudos for that.

I do have two questions. First, does your MM patch for the fuel tanks affect third-party tanks such as KW's? Frankly the stock tanks are fugly and I'll phase them out as soon as better modded tanks catch up to 1.0. Second, and the dumber of the two, what exactly the is the ...appeal of using these engines. Maybe I am a little plebeian, but theyre more expensive, and require considerably more fuel to get the same dV. Is high ISP their sole redeeming merit or is there something else to them?

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OMG yes, now I don't have to do this. I'm starting to think you can read my mind. Now all we need are some fuel tanks and I'll never have to use stock parts again. I'm working on a set that has a more standardized form than the random squad ones and was planning to include H2/LOX versions, but they won't approach this level of quality.

I can't tell if you've done emissives yet, but if you haven't and plan to can I suggest doing the 'inside only' look, instead of making the whole bell orange?

Also, can I ask how you determined the H2 fuel ratios for the stock tanks?

Edit: also, I think Yucutan is spelled Yucatan.

Edited by Starbuckminsterfullerton
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I really like how the heavy 3.75m engine resembles an RS-68 used on a Delta IV Heavy, kudos for that.

I do have two questions. First, does your MM patch for the fuel tanks affect third-party tanks such as KW's? Frankly the stock tanks are fugly and I'll phase them out as soon as better modded tanks catch up to 1.0. Second, and the dumber of the two, what exactly the is the ...appeal of using these engines. Maybe I am a little plebeian, but theyre more expensive, and require considerably more fuel to get the same dV. Is high ISP their sole redeeming merit or is there something else to them?

Yes to the fuel-tank patch affecting third-party tanks. It matches every installed part that contains LFO and doesn't already have an FSfuelSwitch.

Advantage of these engines is 1) Isp, and 2) filling in some gaps in the stock lineup. The KS-68 Mars fits nicely between the stock Rhino and Mammoth.

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No trench effects. Other then that I haven't seen any problems yet.

Here is a dirty patch

@PART[*]:HAS[@MODULE[ModuleEnginesFX],!MODULE[ModuleSurfaceFX]]:Final
{
MODULE
{
name = ModuleSurfaceFX
thrustProviderModuleIndex = 0
fxMax = 0.5
maxDistance = 50
falloff = 1.7
thrustTransformName = thrustTransform
}
}

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Can someone make a MM config for the LV-N to give it LqdHydrogen fuel? EDIT: I just changed the NTR config from NearFuture to change it to LqdHydrogen instead of LiquidHydrogen

Here's a patch that targets every engine that uses LF without Oxidizer or IntakeAir, including the 3.75m NTR from the Taurus HCV. Will probably work for Atomic Age when I get those installed.


@PART[*]:HAS[@MODULE[ModuleEngine*]:HAS[@PROPELLANT[LiquidFuel],!PROPELLANT[Oxidizer],!PROPELLANT[IntakeAir]]]
{
@MODULE[ModuleEngine*] {
@PROPELLANT[LiquidFuel] {
@name = LqdHydrogen
}
}
}

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