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[1.11.x] Cryogenic Engines: Liquid Hydrogen and Methane Rockets! (Mar 9, 2021)


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it's been awhile since I've flown these engines, do the particles remain static like that or do they travel down the stream? I ask because while they do look like shock cells, I think that effect produces a standing wave and if the particles are behaving like most KSP FX, the wave they produce is not standing. I think it is just a product of the exhaust particles being circular.

Shock diamonds or no, if you don't like the look increasing the particle rate/density would alleviate the effect.

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yeah it doesn't really look like a shock diamond/standing wave, they're just coming out too fast or there's not enough of them. A shock diamond should generally look like really enlongated ovals that overlap on the ends, which might actually be doable with KSP particles, I haven't looked into it at all.

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Minor bug report: In CryoEnginesFuelTankSwitcher.cfg you have :NEEDS[!modularFuelTanks]:NEEDS[!RealFuels], however, MM will only accept one NEEDS node, meaning that this will be applied even in the presence of RF. It should be :NEEDS[!RealFuels&!ModularFuelTanks]

EDIT: CryoEnginesModularFuelTanks.cfg also needs :NEEDS[!RealFuels] on all of its patches

Edited by blowfish
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Minor bug report: In CryoEnginesFuelTankSwitcher.cfg you have :NEEDS[!modularFuelTanks]:NEEDS[!RealFuels], however, MM will only accept one NEEDS node, meaning that this will be applied even in the presence of RF. It should be :NEEDS[!RealFuels&!ModularFuelTanks]

EDIT: CryoEnginesModularFuelTanks.cfg also needs :NEEDS[!RealFuels] on all of its patches

Updated CryoEnginesModularFuelTanks.cfg matching IFS patch for resource amounts and tank mass. Costs are a bit odd, since IFS patch costs for stock tanks are the default drycosts but including resource costs. I've changed this and made the drycosts ~22% more expensive than LF/Ox tanks excluding resource costs.

Edited by funk
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Is it intentional, that eg the "VL-1 'Volcano' Cryogenic Rocket Engine" is strictly better than the Poodle stock engine?

Less mass, much better thrust, enormously better atmo ISP, much better vac ISP...

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Is it intentional, that eg the "VL-1 'Volcano' Cryogenic Rocket Engine" is strictly better than the Poodle stock engine?

Less mass, much better thrust, enormously better atmo ISP, much better vac ISP...

Weight of the fuel tanks is vastly higher. Otherwise the poodle is just not very good.

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Weight of the fuel tanks is vastly higher. Otherwise the poodle is just not very good.

Using interstellar fuel switch, I did an experiment. For the same total mass, the Volcano/LH2/OX combination is always superior to the Poodle/LFO combination int terms of dV, vac TWR and for atmo TWR they are playing in different worlds anyways.

Except for funds (which are usually negligible), the Poodle is simply outclassed.

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Using interstellar fuel switch, I did an experiment. For the same total mass, the Volcano/LH2/OX combination is always superior to the Poodle/LFO combination int terms of dV, vac TWR and for atmo TWR they are playing in different worlds anyways.

Except for funds (which are usually negligible), the Poodle is simply outclassed.

If you want to make an efficient rocket, then you never use the poodle. ;)

The engine is also completely outclassed by the skipper in terms of weight efficiency. As said, thats more of a stock balancing issue. Similar the 1.25m engines are all kinda inefficient.

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Here is my favorite launcher i made with Cryo engines and FTP.

Delta IV-EELV1:eMfbqv7.png

iIHhcSI.png

RX9ICV1.png

vG1StPC.png

N3S3HiC.png

The EELV1 gets around 50 tons into 200km orbit and 60-70 tons into direct Munar ascent.

The EELV2 gets more than 100 tons (didn't have any heavier payloads) into 200km orbit, high orbit, direct Munar and Minmus ascent and still has enough to make the trip back or some sketchy transfer maneuver.

All you need is a cryo engine and a crap load of fuel to get pretty much anything into orbit :D

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Liking the idea of this mod and it would be a very good fit for Interstellar (extended) due to Liquid Hyrdogen pretty much being KSP-IE's default fuel.

Indeed you have used the fuel switch module from KSP-IE.

I'd rather however the engines ran on Hydrolox (Liquid Hydrogen / Liquid Oxygen) . . . . "Oxidiser" (whatever that might be!) is not something used very much by KSP-IE which seems to like to keep the stock fuels and its own quite strictly separated.

It should be pretty easy to knock up a file to replace oxidiser with Liquid O2 as you already did for LF/O . . . . in fact whilst I'm no KSP modder, from the look of the file I may be able to work out how to do it myself. I'll give it a crack.

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Here is my favorite launcher i made with Cryo engines and FTP.

Delta IV-EELV1:http://i.imgur.com/eMfbqv7.png

http://i.imgur.com/iIHhcSI.png

http://i.imgur.com/RX9ICV1.png

http://i.imgur.com/vG1StPC.png

http://i.imgur.com/N3S3HiC.png

The EELV1 gets around 50 tons into 200km orbit and 60-70 tons into direct Munar ascent.

The EELV2 gets more than 100 tons (didn't have any heavier payloads) into 200km orbit, high orbit, direct Munar and Minmus ascent and still has enough to make the trip back or some sketchy transfer maneuver.

All you need is a cryo engine and a crap load of fuel to get pretty much anything into orbit :D

Awesome Launcher!

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It should be pretty easy to knock up a file to replace oxidiser with Liquid O2 as you already did for LF/O . . . . in fact whilst I'm no KSP modder, from the look of the file I may be able to work out how to do it myself. I'll give it a crack.

Ok hows this:

// Sets cryoEngines to use Liquid Hydrogen / Liquid Oxygen

@PART[cryoengine-125-1]
{
@MODULE[ModuleEnginesFX]
{

@PROPELLANT[Oxidizer]
{
@name = LqdOxygen
@ratio = 4
}

}
}
@PART[cryoengine-125-2]
{
@MODULE[ModuleEnginesFX]
{

@PROPELLANT[Oxidizer]
{
@name = LqdOxygen
@ratio = 4
}

}
}
@PART[cryoengine-25-1]
{
@MODULE[ModuleEnginesFX]
{

@PROPELLANT[Oxidizer]
{
@name = LqdOxygen
@ratio = 4
}

}
}
@PART[cryoengine-25-2]
{
@MODULE[ModuleEnginesFX]
{

@PROPELLANT[Oxidizer]
{
@name = LqdOxygen
@ratio = 4
}

}
}
@PART[cryoEngine-375-1]
{
@MODULE[ModuleEnginesFX]
{

@PROPELLANT[Oxidizer]
{
@name = LqdOxygen
@ratio = 4
}

}
}
@PART[cryoengine-375-2]
{
@MODULE[ModuleEnginesFX]
{

@PROPELLANT[Oxidizer]
{
@name = LqdOxygen
@ratio = 4
}

}
}

I edited the LFO file in the extras folder, if I've interpreted it correctly this should simply change Oxidizer to Liquid Oxygen, have it burn 4 units of LO2 for every unit of LH2 (as the Hydrolox tanks seem to be set up in KSP-IE) whilst keeping the ISP the same (deleted the atmo curve bit). I think. . . . as I said I'm no KSP modder, and I'm sure there must be a more efficient way to make this bulk change across all the engines at once rather than one at a time!

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Nah, doesn't work, even when I maintain the file structure and filename of the LFO file, oh I also realised that the ratio should be 0.25 not 4. . . . . . but anyway, irrelevant as it doesn't work.

Clearly I should leave it to someone who knows what they're doing!

Edit: Ok, editing the individual part.cfgs in exactly the same way does work. Guess I'll do that for now as I can't work out the "Extras" file.

In terms of balance, when running on Hydrolox the engine produce slightly more deltaV for and equivalent weight of ship, however larger fuel tanks are needed due to both the reduced density of LqdOxygen compared to Oxidiser and the fact it burns at a ratio 0.25 rather than 0.1.

I'm happy it doesn't really unbalance anything.

Edited by Bishop149
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Do you do requests? I've got one or two

1.

A liquid hydrogen / oxidiser linear aerospike like on the X-33

976px-Twin_Linear_Aerospike_XRS-2200_Engine_PLW_edit.jpg

This one manages 909kN with a 339s isp at sea level and 1184kN with a 437s isp in a vacuum. It'd be very useful for spaceplanes on eve :)

2.

A liquid hydrogen jet engine like on the CL-400 or the air-breathing mode of the SABRE (or maybe even a mode-switching one like the sabre)

These would be incredibly useful for cryogenically fuelled SSTOs

SABRE's air-breathing mode has an isp at sea level of 3,600 seconds and produces reasonable thrust right up to mach 5.5

Just a couple of things I thought'd be nice to have :)

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When do these cryo engines benefit over Liq/Oxy engines? The Liq/Oxy seem to have much higher delta V.

Don't get me wrong, I love that they are not overpowered, but I am still curious as to where the engines are most beneficial.

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When do these cryo engines benefit over Liq/Oxy engines? The Liq/Oxy seem to have much higher delta V.

Don't get me wrong, I love that they are not overpowered, but I am still curious as to where the engines are most beneficial.

They have higher Isp. This means that for the same overall mass you will get more delta-v. But I'm guessing you did your tests with the same tank volume - note that hydrogen is less dense so you need more tanks to get to the same mass

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They have higher Isp. This means that for the same overall mass you will get more delta-v. But I'm guessing you did your tests with the same tank volume - note that hydrogen is less dense so you need more tanks to get to the same mass

Ahh less dense. I did see the delta-v difference but did not pay attention to mass. Thank you for that!

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Do you do requests? I've got one or two

1.

A liquid hydrogen / oxidiser linear aerospike like on the X-33

https://upload.wikimedia.org/wikipedia/commons/thumb/8/8c/Twin_Linear_Aerospike_XRS-2200_Engine_PLW_edit.jpg/976px-Twin_Linear_Aerospike_XRS-2200_Engine_PLW_edit.jpg

This one manages 909kN with a 339s isp at sea level and 1184kN with a 437s isp in a vacuum. It'd be very useful for spaceplanes on eve :)

You might wanna check this out:

http://forum.kerbalspaceprogram.com/threads/121224-1-02-Mk2-Expansion-v1-0-2-5-14-2015

He appears to have what you want . . . .

I6LVW2sl.png

Edited by Bishop149
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Recently, I built two probes headed to the moons of jool, one with NFP Hall Thrusters, and one with Cryogenic H2/LOX. The payloads were similar, but the Cryo engine probe was better in every way (more dV, higher twr, less expensive). I've decided to put moratorium on using Cryo stuff outside of LKO in the interest of realism (read:masochism).

Yet I must ask. Is there any possibility of implementing H2 bleed off? Perhaps as an optional 'hardcore' version along the lines of the recently announced changes to Heat Control?

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