[0.20] Modular Fuel System 1.3/realistic fuels, reconfigurable fuel tanks and engines

[Starwaster]

[bs1110101]

I (still) have no idea how to make any new resources want to show up in tanks, but i'v figured out more or less everything else to make the gas core ntrs.

Also, i sense that's going to turn into a full blown realism patch for kethane, and i cant wait for that to be done.

[Starwaster]

I (still) have no idea how to make any new resources want to show up in tanks, but i'v figured out more or less everything else to make the gas core ntrs.

Also, i sense that's going to turn into a full blown realism patch for kethane, and i cant wait for that to be done.

Well I noticed he gave kethane density very close to methane so I'm treating it as methane with regards to NTR performance. Alas, I still have to GET the ship some kethane to fuel it and I'm not quite that far along in my kethane mining. In fact I ran into a nasty physics problem with the largest stock kethane tank where if you stack 6 of them symmetrically around a central tank and then fill them they violently tear themselves apart and anything they're attached to. I think it's that ridgy thing up the side because when I hacked the part.cfg file to turn it around it stopped happening.

Anyway, this is how to add new resources

RESOURCE_DEFINITION
{
	name = TestResource2
	density = 0.00625
	flowMode = STACK_PRIORITY_SEARCH
	transfer = PUMP
}

Add it to one of the tank types so you can fill that tank with the resource

@TANK_DEFINITION[Default]
{
	TANK
	{
		name = TestResource2
	}
}

Configure an engine to process the new resource

	MODULE
	{
		name = ModuleEngineConfigs
		configuration = TestResource2 // This line is to tell the engine what its default configuration is if there is more than one fuel configuration it can handle
		modded = false		
		CONFIG
		{
			name = TestResource2
			thrustVectorTransformName = thrustTransform
			exhaustDamage = True
			ignitionThreshold = 0.1
			minThrust = 0
			maxThrust = 400
			PROPELLANT
			{
				name = TestResource2
				ratio = 1.0
				DrawGauge = True
			}
			atmosphereCurve
			{
				key = 0 450  //  Isp in vacuum
				key = 1 250 // Isp at sea level or 1 atmosphere
			}		
		}				
	}				

[bs1110101]

Very helpful, how can i make it only go in tanks monopropellant can go in?

[Starwaster]

Very helpful, how can i make it only go in tanks monopropellant can go in?

@TANK_DEFINITION[Monopropellant]
{
	TANK
	{
		name = TestResource2
	}
}

That's what the @TANK_DEFINITION does. It means 'at TANK_DEFINITION[Monopropellant] insert TANK{<tank stuff>}'

In other words, insert our resource into the Monopropellant tank definition.

[Designer225]

Does using this mod for another mod require permission?

[NathanKell]

License: http://forum.kerbalspaceprogram.com/showthread.php/31706-0-20-Modular-Fuel-System-1-3-realistic-fuels-reconfigurable-fuel-tanks-and-engines?p=462889&viewfull=1#post462889

[Starwaster]

Ok, been working on this on and off for awhile, it's not perfect but I've kind of stalled due to time availability but it's mostly ready. I hope. The motivating force behind the creation of this configuration file was to make nuclear engines more attractive. Even though there was a mass issue discovered with LF/OX tanks, I think there's still a prevailing attitude that nuclear engines are undesirable. So one thing this does is provide alternative propellents that although they have lower Isps, I find the increased reaction mass offsets that for a net improvement in delta-V.

Starwaster's Real Fuels Additions

Changes:

The following resources can all be used directly as propellents in the nuclear rocket (LV-N):

Kethane (I used Methane as a basis for determining performance, not a far stretch as kethane's mass is very close to liquid methane)

Water (low Isp but the increased reaction mass seems to offset that. Can be added in VAB or converted from Kethane in a Kethane Converter)

SlushH2 (Hydrogen slush, It's denser so you can store more of it by mass. slight improvement in delta-V)

LiquidAmmonia (lower Isp but denser so provides a boost to delta-V)

Support in Kethane Converter for ammonia and water. (there's already support for H2/O2)

Composite material cryogenic tank. This ONLY stores cryogenic fuels and is 30% lighter than standard cryogenic tanks. It's based on real technology. That doesn't exclude the possibility that it unbalances things but so far it seems within reasonable limits to me. If people find it otherwise, please let me know. If you have either KW Rocketry installed or NovaPunch then you will find several tanks of this type in the parts list. I haven't got to the Squad tanks yet, sorry.

Finally, most stock engines (I probably missed some of the smaller ones) and all KW Rocketry engines can be configured to run on Kethane & Liquid Oxygen

Kethane mod is not a requirement, if you don't have it you just won't be able to use Kethane in the engines. (it will show up for some tanks but they cannot be filled with kethane no matter if it is installed or not). If you have it installed however, then it means you can refuel in the wild. Or in situ as they say.

Please try it out and enjoy. Share any concerns about balance.

Edited September 29, 2013 by Starwaster
9-29-2013 organized dropbox files

[NathanKell]

While you're adding...do you suppose you could add hypergolics?

[Starwaster]

While you're adding...do you suppose you could add hypergolics?

I suppose.... but why? Their main characteristic is that they don't need an ignition source right? But that's not a concern in KSP anyway.

And aren't they lower performance fuels? Where would you want to use them? Except maybe for OMS type engines?

I guess in short, what sort of benefit that can actually translate to an in-game situation would make them desirable?

[NathanKell]

Verisimilitude. Per my KATO Mission Reports thread, I'm only allowing myself to reignite hypergolic OMS thrusters.

If/when I have time (HAHAHA) I want to make a mod to limit engine ignitions (and also change so you can't arbitrarily throttle [most] engines, at best you'll get 100-60%, at worst "on" or "off, never to be lit again").

And no, from at least what I've seen they seem to have slightly better performance than kerolox.

[Starwaster]

Verisimilitude. Per my KATO Mission Reports thread, I'm only allowing myself to reignite hypergolic OMS thrusters.

If/when I have time (HAHAHA) I want to make a mod to limit engine ignitions (and also change so you can't arbitrarily throttle [most] engines, at best you'll get 100-60%, at worst "on" or "off, never to be lit again").

And no, from at least what I've seen they seem to have slightly better performance than kerolox.

Ah. Well, nuclear engines qualify then

I'll take a look at it but I would probably do it as a separate config file. Uhm.... on which subject it should be possible to configure the engines via the same MFS engine configuration to not be throttleable but that's all kinds of dangerous. Unless there's a lower limit. I forget how that works cause I've never messed with it. Reason I say dangerous is that the freakin KW Griffon wants to go off like popcorn kernels in a microwave. More dangerous than the mainsail

Regarding hypergols performance, I guess we better separate out whether we're talking Isp or thrust or both and which hypergolic mixtures we're talking about. Some are safer than others and probably lower perfomers while others are really dangerous or really corrosive (like fluorine & H2)

[NathanKell]

Better count the Griffon as like an F-1A, then, throttleable to 75%.

Should be possible to do the throttling that way*, but I'm not sure whether you then have to set an actiongroup (or right-click) to turn the engine off, rather than throttling to 0. And it wouldn't fix the reignition problem, for that you do (I think) need a plugin, no?

*there's a maxthrottle and minthrottle in the ModuleEngines node. Or something like those names.

I've mostly been looking at early stuff--like the conversion of Titan's engines from kerolox to hypergol. But I haven't dug in depth. From what I've seen, for similar timeframe engines, you get about the same TWR with maybe 1-5% better Isp.

I think just N2O4/Hydrazine, or UDMH, or Aerozine, or whatever floats your boat, would work. Could use it as reasonable standin for "non-cyrogenic dense fuel" and, eventually "that can be restarted easily."

I wouldn't touch Flourine with a ten foot pole, in real life or with a mod.

I also hope to write something that might make it explode on occasion. I'm getting tired of lack of failures in KSP (weird, I know).

[Starwaster]

Better count the Griffon as like an F-1A, then, throttleable to 75%.

Should be possible to do the throttling that way*, but I'm not sure whether you then have to set an actiongroup (or right-click) to turn the engine off, rather than throttling to 0. And it wouldn't fix the reignition problem, for that you do (I think) need a plugin, no?

*there's a maxthrottle and minthrottle in the ModuleEngines node. Or something like those names.

I've mostly been looking at early stuff--like the conversion of Titan's engines from kerolox to hypergol. But I haven't dug in depth. From what I've seen, for similar timeframe engines, you get about the same TWR with maybe 1-5% better Isp.

I think just N2O4/Hydrazine, or UDMH, or Aerozine, or whatever floats your boat, would work. Could use it as reasonable standin for "non-cyrogenic dense fuel" and, eventually "that can be restarted easily."

I wouldn't touch Flourine with a ten foot pole, in real life or with a mod.

I also hope to write something that might make it explode on occasion. I'm getting tired of lack of failures in KSP (weird, I know).

Check out this page if you haven't already. Towards the bottom.

Yeah, action group definitely. Only I'd let it go to 100% maximum *IFF* there's also a minimum then you could do a range of 75%-100%

Pretty sure you'd need a plugin to keep the engine from being re-ignited. There's a few really kludgey methods I can think of to do it with config only, like having an ignition 'resource' is renewed as long as the engine is operating (you'd do that with a generator linked to engine power). It could be initially filled via the pumps in the launch 'towers'. But that's really kludgey and not really the right way to do it.

on the subject of fluorine, I saw an interesting quote (obviously sarcastic) saying something to the effect that at high temperatures, fluorine lost its 'gentle and loving' nature and started getting really nasty. Bah, I'm probably ruining it but it was funny at the time.

Doing this set of configs I'm noticing an interesting bug here. Kethane tanks are NOT supposed to be fillable and in the VAB they appear not to be but I noticed that they're gaining mass nonetheless. Put one on the launch pad and sure enough the sucker is fully of kethane. Not supposed to be like that because you're supposed to have to mine that stuff

Hopefully I just made a mistake somewhere but I think it's a MFS bug and there's no ialdoaboath to report it to

Edit: Yup. If you use the auto-fill button where it looks at the attached engines and chooses which fuels in which ratios then it will ignore the fillable property. If you use the add/update buttons it does not do that.

Edit#2: Ok yeah. I've seen the option for minThrust but I just sort of edit them out of my brain since I haven't used them at all. For the Griffon XX this would be 65%-100% (except of course that I'm not sure exactly where it starts to overheat)

			minThrust = 2470
			maxThrust = 3800

Edited September 15, 2013 by Starwaster

[NathanKell]

The more I look, the more I find N204/UDMH to have a lower Isp than kerolox. So never mind that bit. Small sample problem.

You say "this page"--which page? Because your post _is_ the bottom of this page.

That kludge sounds pretty cool, actually, but yeah, might as well write a plugin.

I saw that too, heh.

Either in Eyes Turned Skyward or the Charlie Stross story linked from there (dealt with FOOF as oxidizer...yikes!).

Huh. Interesting bug. Probably just a missing if() block somewhere, then.

Think for now, like with folks in the DRE thread, community has to step in to maintain MFS (and thanks to ialdabaoth's generous license, which requires only that we honestly reaffirm how awesome s/he is, we can).

[Starwaster]

The more I look, the more I find N204/UDMH to have a lower Isp than kerolox. So never mind that bit. Small sample problem.

You say "this page"--which page? Because your post _is_ the bottom of this page.

That kludge sounds pretty cool, actually, but yeah, might as well write a plugin.

I saw that too, heh.

Either in Eyes Turned Skyward or the Charlie Stross story linked from there (dealt with FOOF as oxidizer...yikes!).

Huh. Interesting bug. Probably just a missing if() block somewhere, then.

Think for now, like with folks in the DRE thread, community has to step in to maintain MFS (and thanks to ialdabaoth's generous license, which requires only that we honestly reaffirm how awesome s/he is, we can).

Oh crap I forgot to paste the URL. Deerrrrpppp

http://www.braeunig.us/space/propel.htm

Edit: btw, all my interest in doing the config to add new fuels was prompted by talk of the nuclear rocket being broken in Real Fuels. Or rather it prompted a lot of research in which I discovered that even in the aerospace industry, not everyone is enamored with nuclear rockets in general (or hydrogen as a propellent in nuclear rockets). Great Isp offset by a choice of having to accept either lower reaction mass or voluminous H2 fuel tanks to compensate. I've come to the conclusion that even once you fix the tank mass issues, nuclear works the way it probably would in reality. So maybe the problem is reality sucks.

Edited September 16, 2013 by Starwaster

[NathanKell]

Thanks! Been using that site for spacecraft specs (only place I found that actually lists the propellant mass of the Mercury LES, for example!)

Encyclopedia Astronautica has the a similar version for max vac Isp too.

Reality...not so hot, yeah. :\

[Starwaster]

Thanks! Been using that site for spacecraft specs (only place I found that actually lists the propellant mass of the Mercury LES, for example!)

Encyclopedia Astronautica has the a similar version for max vac Isp too.

Reality...not so hot, yeah. :\

I like EA but those damn Flash ads kill my computer if I forget and leave any pages from that site up. especially in multiple tabs

[briansun1]

how do you install it?

[rhoark]

I wouldn't get hyper-specific with counterparts to real-world fuels. Just make a new fuel called "HypergolicFuel" with parameters inside a realistic window, and leave specifics to the imagination.

[Starwaster]

how do you install it?

Modular Fuel System? Look inside the zip file. Copy the GameData folder to your KSP_Win folder, which is wherever you put it.

If you are asked if you want to overwrite anything answer yes.

A folder named ModularFuelTanks will be created in your GameData folder. You're finished at this point unless you want to install Real Fuels, in which case you open the ModularFuelTanks folder, find the realfuels.zip file and unzip the contents to ModularFuelTanks. (or if you can just open the zip file like a normal folder then do so and copy the contents to ModularFuelTanks)

[amo28]

Hey all. Great mod here, I'm just now working my way through it, and it works great. I've even been able to add compatibility to non-stock engines by following Starwaster's MM cfg mods. (Great work with those, man. You put a lot into them.)

I've got two questions, though.

First, I'm finding that I get the highest dV and thrust by using the LiquidFuel/LOX combination. The only drawback to it seems to be the increased weight. However, I'd like to keep the weight down on my upper stages, but when I'm trying to use the LH2/LOX configuration, the weight goes down, thrust goes down, ISP goes up, but my dV is extremely low. Lower than it would be to use regular LiquidFuel/Oxidizer, and much lower than using the heavier LiquidFuel/LOX config for the same engine and tanks.

I'm wondering if this doesn't happen to everyone and something is wrong with my engine configs, or is this how LH2/LOX is supposed to function? If that's the case, what's the function of LH2/LOX?

My 2nd question is what does everyone use the different fuel configurations for? Do you use a specific config for your lifter stages and another for your payload? Any comparison to what real world craft are using? The shuttle's OMS engines used an LH2/LOX configuration and had about 1000 m/s dV, from what I could find. That doesn't seem like a lot to me for use in KSP. So what do you guys use it for?

[NathanKell]

OMS used N2O4/MMH, actually, a hypergolic combination, very storable (though toxic). Importantly NOT hydrolox, which is cryogenic.

The point of LOX/LH2 (hydrolox)--what the SSMEs used, fuel for which in the external tank, is that the fuel is very light for its volume. You need lots of tanks. Try seeing how much dV you get with a hydrolox engine with the _same fuel mass_ not the _same fuel volume_.

Part of what's wrong with hydrolox (vs. kerolox) in Modular Fuels is that the Isp increase is proportionally too low. KSP's stock Isps are actually way too high for the liquid-fuel engines (NASA would kill for a 370Isp vacuum Kerolox engine! Let alone 390!). Although that's kinda made up for by the low TWRs. But considering the increase (~310s to ~450s going from kerolox to hydrolox) the MFS LOX/LH2 engines should be getting on the order of ~560s Isp Vacuum.

[Starwaster]

thx amo28! I used to be fairly solidly of the belief that Isp was everything, and it definitely is important but delta-V is also linked to the mass of the propellant you're throwing out the back. I guess one way of looking at it is that H2 might provide the best Isp in a given engine design but then you have to look at the fact that because it's so light you might need a lot more of it to achieve your desired delta-V. that's especially true of the nuclear engines. and more H2 means more tank dry mass

I do find though that it's become my 'go to' fuel for my heavy lifters simply because it lightens my stages. kethane is interesting too since I modeled the kethane engine configurations from real life methane examples so it's a somewhat lower Isp fuel but its higher density means more mass to 'toss out the back'. kethane tanks arent supposednto be fillable in the vab but I've noticed if you 'auto-configure' your tanks, MFT will load it in even though it says it isn't. definite bug

personally the way I'd like to see it work is that if you recover a vehicle with any kethane in it, that quantity will become available to MFT in the VAB. should be feasible if the API allows hooking into the recovery system.

[p3asant]

I just had to register to say this is perhaps the most awesome mod (in relation to content) !

This makes creating realistic looking rockets very much easier (with procedural fairings).

Next procedural engines so we can get out 20m diameter rockets off the ground?