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

[Titan Space Agency]

Yes XD lol

[Starwaster]

The isp of nerva engines can reach 1000 with ease, and if we use better materials so the core can reach higher temperatures then the isp increase even more.

All those values that you mention are from the 60s.

The best way to make a nerva engine is with radiators to release the heat using a brayton cycle so we not need to shutdown the core, and we will generate electricity when we dont needed to thrust.

The good about nerva engines is that only needs H2, this is the half of the fuel that chemicals rockets needs and we can get this from water, using the core to separate h2 from water and we have fuel again. So any asteroid or little planet (duna) with water it would serve to supply.

The 60s you say? That's funny, I think that's about where Kerbal technology is at right now.

Thanks for the information provided (I saw the same at Project Rho, I recommend it to all KSP players and modders) but I'm more interested in whether the values for the relevant parts in the game and in this mod are accurate, since I shared a concern that others have voiced that there was something wrong in the mod that was robbing the LVN of the performance it should be achieving in-game. I no longer have that concern; liquid H2 performs close to what it should IRL. The problem is that people just aren't carrying enough of it with them because they don't realize that while efficient as a fuel that it's not very dense. So I think the correct answer to those concerned about LVNs and how they perform with Real Fuels in this mod is it's performing as it should and they need to carry a lot more H2 with them.

The isp could be bumped up to 1,000 without straying very far from the engine the LVN is supposed to represent. That will net you a 17% increase in the ÃŽâ€v of a given spacecraft.

Another solution would be the addition of more fuel types appropriate to the LVN. To that end I've been experimenting with adding liquid ammonia as a fuel type. Ammonia can be used in nuclear thermal rockets (NTR) like the LVN.

The downside is a substantial reduction in ISP, down to 520 from 850. (IRL ammonia's greater molecular mass translates to lower exhaust velocity)

The upside is that you can carry more fuel with you in a given tank. I don't have the exact numbers right now but my fuel lasted about 5 times longer and (more importantly deltav was substantially increased as well)

Unfortunately ammonia being so much more denser than H2 made it a lot harder getting my ship into orbit. Probably it would be better to send it up with empty tanks and then fuel it in orbit.

I also was toying with adding solid ammonia which would allow carrying even MORE fuel but to be realistic, the tank mass overhead needs to be much higher to take into account the necessity for heating and thawing the fuel so it can be pumped.

Something else I want to try is slush hydrogen and metallic hydrogen. That would get performance back to H2 levels (for slush) but you can carry more of it without dealing with the weight issues that ammonia has.

I saw mention that metallic hydrogen also offers increased efficiency as a fuel type but I need to track down some actual data on that.

[RuBisCO]

I have an ammonia fuel probe orbiting Eeloo, ISP 550, small spherical tank, had nearly 6000 delta V because all it was as a probe and two Kethane sensors and a tiny 40 kN 1mNTR1 engine. I had to change the rate of nuclear fuel lose though. I made it so the nuclear engines have enough fuel for 7 years of generating power or 6000 secs of engine operation.

A centrifugal reactor core should be able to do higher ISP (because fuel elements are held in place by centrifugal or is it centripetal force, which ever, instead of structural strength which few things have left at >3500K), but should provide a nice "twist": would need reaction wheels to counter the torque of the spinning core.

Still waiting on someone to create a crycooler to prevent LH2/LO2 boil off, its not like its impossible IRL: http://hydrogenresearch.org/FR04/UCF--Chow--Reverse%20Turbo%20Brayton%20Cycle%20Cryocooler.%20.%20..PY2004-FY0405.pdf

Edited August 7, 2013 by RuBisCO

[The Lone Wolfling]

I have an ammonia fuel probe orbiting Eeloo, ISP 550, small spherical tank, had nearly 6000 delta V because all it was as a probe and two Kethane sensors and a tiny 40 kN 1mNTR1 engine. I had to change the rate of nuclear fuel lose though. I made it so the nuclear engines have enough fuel for 7 years of generating power or 6000 secs of engine operation.

Nice way around the density issues.

A centrifugal reactor core should be able to do higher ISP (because fuel elements are held in place by centrifugal or is it centripetal force, which ever, instead of structural strength which few things have left at >3500K), but should provide a nice "twist": would need reaction wheels to counter the torque of the spinning core.

Something spinning at a constant speed shouldn't provide any torque, unless you're talking about gyroscopic effects?

Still waiting on someone to create a crycooler to prevent LH2/LO2 boil off, its not like its impossible IRL: http://hydrogenresearch.org/FR04/UCF--Chow--Reverse%20Turbo%20Brayton%20Cycle%20Cryocooler.%20.%20..PY2004-FY0405.pdf

Same. Even without the mass issues boiloff makes LH2 useless for later stages, which is rather contrary to the intended purpose.

Edited August 7, 2013 by The Lone Wolfling

[RuBisCO]

Something spinning at a constant speed shouldn't provide any torque, unless you're talking about gyroscopic effects?

IRL friction between the wheel and the ship will cause the wheel to slow down and the ship to spin up, constant energy needs to be imputed to prevent this. Also spinning up the wheel and spinning down would put a lot of torque on the rest of the ship, and yes gyroscopic effects would occur as well.

Same. Even without the mass issues boiloff makes LH2 useless for later stages, which is rather contrary to the intended purpose.

I've tried to make a part that does this but failed, I can't get it to deactivate boil off in the tanks of the ship it is attached too, rather the best I can do is globally deactivate boil off. I rather have a crycooler that needs power for realism sake.

[Starwaster]

I've tried to make a part that does this but failed, I can't get it to deactivate boil off in the tanks of the ship it is attached too, rather the best I can do is globally deactivate boil off. I rather have a crycooler that needs power for realism sake.

Bottom line is that turning it off is exactly what you're trying to do but you're trying to impose a realistic penalty for doing so. So turn the thing off and add module to the tank part that eats electricity.

MODULE
{
	name = ModuleGenerator
	isAlwaysActive = true

	INPUT_RESOURCE
	{
		name = ElectricCharge
		rate = 1
	}
}

Change rate to whatever you think it should be and call it a day.

[RuBisCO]

Bottom line is that turning it off is exactly what you're trying to do but you're trying to impose a realistic penalty for doing so. So turn the thing off and add module to the tank part that eats electricity.

MODULE
{
	name = ModuleGenerator
	isAlwaysActive = true

	INPUT_RESOURCE
	{
		name = ElectricCharge
		rate = 1
	}
}

Change rate to whatever you think it should be and call it a day.

I was thinking more along the lines of a part (heatsink) I could attach to any tank or ship, not have the tanks themselves do it.

[p1t1o]

Hi guys,

if one of you does make a part that can halt/slow boiloff and uses electricity, would it be possible to make it available to us? I'd certainly find it useful

Not enough uses for electricity yet IMO, and this use would be really...well, useful.

Cheers!

[RuBisCO]

Sure! I was thinking of using a heatsink model from another mod, not sure if that is valid.

[AngelLestat]

Starwaster: The 60s you say? That's funny, I think that's about where Kerbal technology is at right now.

Kinda Agree. Now we are in free mode. So we can use any part that we want without worry in cost or tier.

I guess that when we get the career mode, we will start with low technology and heavy vehicles and we will improve from there until maybe 50 years in our future.

Yeah, if the tank mass ratio cant be fix, then change the ISP a little or maybe use another fuel like you said can be the solution.

[Starwaster]

I'm going to release my fuels here once I figure out how I screwed up the KSPX nuclear engine. It'll be slush H2 (slush SHOULD totally be usable without requiring a reconfig of the engine but I'm not sure how to go about that or if it can be done... maybe create a separate tank for liquid H2 and then a generatorModule to turn the slush into liquid? Too complex? Even doable using only the Real Fuels configs?) and ammonia. Slush is marginally denser so it'll provide a little extra deltaV. Ammonia provides a lot more but lowers overall isp and if you want to get a lot of it into orbit, it's a bit of a pain. Probably a lot more than it needed to be because of poor rocket design on my part.

According to Project Rho, NERVA style engines can use a very wide range of fuels with varying performance hits. Methane was actually the second best performer but decomposes in the chamber to some nasty compounds that would render the engine unusable unless the fuel rods could be purged of all the gunk. Ammonia was third in raw performance but is second in desirability because it has a much slower boil-off rate and decomposes into hydrogen and nitrogen in the chamber. http://www.projectrho.com/public_html/rocket/enginelist.php#id--Nuclear_Thermal--Solid_Core. I might do them all eventually but only if I can figure out how to implement the harmful side effects of some of them. Water would be plain dumb, it doesn't make a good propellant and it's too heavy. Unless it were an emergency and you could get some from an ocean. That would be interesting actually. "Lost on Laythe!". Not sure what other mods you'd need for that but you could hypothetically with the right mods set it up so you could totally do wilderness refueling.

FYI, it was mentioned in 2010: Odyssey 2 (or both?) that Discovery used ammonia as a propellant. This was a good thing as Discovery had been in orbit around Jupiter for so long that hydrogen would have boiled off, especially under the environmental conditions that Jupiter imposed.

[Starwaster]

@ialdabaoth, is it possible for Hybrid engines to accept more than two propellant configs? I was trying to reconfigure the big KSPX nuclear engine to accept some new nuclear fuels I'm making (see prev.) but I'm finding the hybrid module seems to be conflicting. It only accepts its hybrid configs (LH2 or LH2+LOX) and ignores anything else I try to add with CONFIG{}

Also, would it be possible to do propellants as an alias? Such liquid H2 & slush H2? Performance would be identical so it should be possible for a single engine to accept either one in the field.

Failing that, using CONFIG{} is it possible to add other modules like if I did something like

CONFIG
{
    MODULE
    {
		name = ModuleGenerator
		isAlwaysActive = true
		INPUT_RESOURCE
		{
			name = ElectricCharge
			rate = 0.5
		}
		INPUT_RESOURCE
		{
			name = SlushH2
			rate = 1
		}
		OUTPUT_RESOURCE
		{
			name = LiquidH2
			rate = 1
		}
    }
}

Would that work do you think? (ignoring for the moment where the LH2 is actually going to go... assume another tank is waiting to accept it, or maybe it would go right to the engines? I'm not sure about that part.

Also, another question about ModuleGenerator, what happens if one INPUT_RESOURCE is unavailable? Do the ones that are available get consumed regardless of whether all are available? And what if there ISN'T a place for the output to go? Are inputs consumed anyway?

[Designer225]

Does anyone know if this version of Modular Fuel Tank is compatible with KSP 0.21?

[Starwaster]

Does anyone know if this version of Modular Fuel Tank is compatible with KSP 0.21?

Yes. Oh, sorry that's less than 10 characters.

Yes, it does work with Kerbal Space Program version 0.21.1

Happy now, Kerbal Space Program forum software?

[Selgald]

I really like this mod, and I tryed the advanced mode. Is it correct that the nuclear rocket now have an insane TWR, but extrem short burntimes? My setup (in normal mode) had a burntime about 20 minutes and a low twr. Now it has a TWR of 99 and a burntime of 1 minute.

[Starwaster]

I really like this mod, and I tryed the advanced mode. Is it correct that the nuclear rocket now have an insane TWR, but extrem short burntimes? My setup (in normal mode) had a burntime about 20 minutes and a low twr. Now it has a TWR of 99 and a burntime of 1 minute.

As I've said before, carry more H2 tanks. Bigger H2 tanks. lots and lots of H2 tanks!

"My god, it's full of H2 tanks!"

Look it's simple math. Your maximum delta-V is dependent on the mass of propellant that you're throwing out and the speed with which it is being thrown out. The heavier the mass that you're ejecting, the more delta-V you have. And H2 is the lightest of the elements. So yeah that means your delta-V suffered for the same volume of propellant. But it's so light that you can carry quite a bit of it around now.

Here's a moduleManager config file I made that adds some more nuclear fuels. It adds: H2 Slush which allows for denser fuel storage than liquid H2 and liquid ammonia. The ammonia is about 9x denser than liquid H2 but has about 60% of the isp. The net gain is that you have longer burn times and more deltaV. The downside is that the increased weight means that if you wanted to carry a lot of it then you better have a robust lift solution ready. (the amount of ammonia where you'd run into problems would probably be that Duna mission you always wanted to do). You could also launch with empty ammonia tanks and then fuel it in orbit with tankers. There's also the addition of solid ammonia with increased tank overhead to account for thawing equipment. For some reason though the solid ammonia is giving me problems, at least in the big nuclear rocket and I'm not sure where I messed it up.

starwaster_fuels.cfg

// starwaster_fuels.cfg
// Starwaster's patch file for adding additional fuel types for the Real Fuels version of Modular Fuel Tanks.
// These are primarily for nuclear engines though they are all possible fuel sources for other engines including standard chemical.
@RESOURCE_DEFINITION[LiquidH2]
{
	@density = 0.0004428125
}
@RESOURCE_DEFINITION[LiquidOxygen]
{
	@density = 0.00713125
}
RESOURCE_DEFINITION
{
	name = LiquidH2O // Primarily as a test article. Potential nuclear fuel but has poor performance characteristics
	density = 0.00625
}
RESOURCE_DEFINITION
{
	name = TestResource
	density = 1.0
}
RESOURCE_DEFINITION
{
  name = SlushH2
  density = 0.00053125 // 85 kg/m³ - Slush H2 is denser 0.00053125
  flowMode = STACK_PRIORITY_SEARCH
  transfer = PUMP
}


RESOURCE_DEFINITION
{
  name = LiquidAmmonia
  density = 0.004261875 //  	681.9 kg/m3 - 9.62x denser than LH2
  flowMode = STACK_PRIORITY_SEARCH
  transfer = PUMP
}

RESOURCE_DEFINITION
{
  name = SolidAmmonia
  density = 0.00510625
  flowMode = STACK_PRIORITY_SEARCH
  transfer = PUMP // done realistically this should not be pumpable, rather it should be converted by another module, probably moduleGenerator, into LiquidAmmonia
}

@TANK_DEFINITION[Default]
{
	@TANK[LiquidH2]
	{
	   @utilization = 0.99
	}
	TANK
	{
		name = Oxygen
		utilization = 1.0
		mass = 0.0
		loss_rate = 0.0
		amount = 0.0
		maxAmount = 0.0
	}
	TANK
	{
		name = LiquidH2O
		utilization = 1.0
		mass = 0.0
		loss_rate = 0.0
		amount = 0.0
		maxAmount = 0.0
	}
	TANK
	{
	   name = SlushH2
	   utilization = 0.975
	   mass = 0.00005
	   temperature = -259
	   loss_rate = 0.0000000005
	   amount = 0.0
	   maxAmount = 0.0
	   note = (requires insulation)
	}	
	TANK
	{
		name = LiquidAmmonia
		utilization = 0.995
		mass = 0.00005
		amount = 0.0
		temperature = -33.3
		loss_rate = 0.00000000005
		maxAmount = 0.0
		note = (requires insulation)
	}
	// Re: Utilization. This is just a totally wild guess. Using a base value of 0.995 based on the value for oxygen; it should be no harder to store than that. 
	// Then assessing a further 10% penalty based on the fact that some system would have to be in place that warms up, liquifies then pumps the ammonia.
	// Note that (to my knowledge) no space agency has considered or published any information on using solid ammonia on a flight.
	// It should still be technically possible as long as you can liquify it.
	TANK
	{
		name = SolidAmmonia
		utilization = 0.895 // Utilization much lower, to simulate the amount of equipment needed to retrieve and thaw solid ammonia chunks
		mass = 0.00005 
		amount = 0.0
		temperature = -80
		loss_rate = 0.0000000000
		maxAmount = 0.0
		note = (requires insulation)
	}
}
@TANK_DEFINITION[Fuselage]
{
	// Changes to LH2 tanks! Reduced mass of tank , increased utilization
	// LV909
	// LF/OX
	// wet mass 61.6
	// dry mass  9.3
	// TWR 0.08
	// DV: 6819 1h:03m:11s
	//
	//
	// Same ship, LVN + 6 fuel tanks
	// LH2
	// wet mass 60.5
	// dry mass 22.19
	// TWR 0.10
	// DV: 8292 1h:28m:19s

	@TANK[LiquidH2]
	{
	   @utilization = 0.99
	   @mass = 0.0000
	}
	TANK
	{
		name = Oxygen
		utilization = 1.0
		mass = 0.0
		loss_rate = 0.0
		amount = 0.0
		maxAmount = 0.0
	}
	TANK
	{
	   name = SlushH2
	   utilization = 0.975
	   mass = 0.00005
	   temperature = -259
	   loss_rate = 0.0000000005
	   amount = 0.0
	   maxAmount = 0.0
	   note = (requires insulation)
	}	
	TANK
	{
		name = LiquidAmmonia
		utilization = 0.995
		mass = 0.00005
		amount = 0.0
		temperature = -33.3
		loss_rate = 0.00000000005
		maxAmount = 0.0
		note = (requires insulation)
	}
	TANK
	{
		name = SolidAmmonia
		utilization = 0.895 // Much harder to simulate the amount of equipment needed to retrieve and thaw solid ammonia chunks
		mass = 1.0 // Mass of equipment referenced above
		amount = 0.0
		temperature = -80
		loss_rate = 0.0000000000
		maxAmount = 0.0
		note = (requires insulation)
	}
}
@TANK_DEFINITION[Jet]
{
	TANK
	{
		name = Oxygen
		utilization = 1.0
		mass = 0.0
		loss_rate = 0.0
		amount = 0.0
		maxAmount = 0.0
	}
	TANK
	{
	   name = SlushH2
	   utilization = 0.975
	   mass = 0.00005
	   temperature = -259
	   loss_rate = 0.0000000005
	   amount = 0.0
	   maxAmount = 0.0
	   note = (requires insulation)
	}	
}
@TANK_DEFINITION[Structural]
{
	TANK
	{
		name = Oxygen
		utilization = 1.0
		mass = 0.0
		loss_rate = 0.0
		amount = 0.0
		maxAmount = 0.0
	}
	TANK
	{
	   name = SlushH2
	   utilization = 0.975
	   mass = 0.00005
	   temperature = -259
	   loss_rate = 0.0000000005
	   amount = 0.0
	   maxAmount = 0.0
	   note = (requires insulation)
	}	
	TANK
	{
		name = LiquidAmmonia
		utilization = 0.995
		mass = 0.00005
		amount = 0.0
		temperature = -33.3
		loss_rate = 0.00000000005
		maxAmount = 0.0
		note = (requires insulation)
	}
	TANK
	{
		name = SolidAmmonia
		utilization = 0.895 // Much harder to simulate the amount of equipment needed to retrieve and thaw solid ammonia chunks
		mass = 1.0 // Mass of equipment referenced above
		amount = 0.0
		temperature = -80
		loss_rate = 0.0000000000
		maxAmount = 0.0
		note = (requires insulation)
	}
}
@TANK_DEFINITION[Cryogenic]
{
	@TANK[LiquidH2]
	{
	   @utilization = 0.99
	   @mass = 0.0000
	}
	TANK
	{
		name = SlushH2
		utilization = 0.975
		mass = 0.00005
		temperature = -259
		loss_rate = 0.0000000005
		amount = 0.0
		maxAmount = 0.0
		note = (requires insulation)
	}	
	TANK
	{
		name = LiquidAmmonia
		utilization = 0.995
		mass = 0.00005
		amount = 0.0
		temperature = -33.3
		loss_rate = 0.00000000005
		maxAmount = 0.0
		note = (requires insulation)
	}
	TANK
	{
		name = SolidAmmonia
		utilization = 0.895 // Much harder to simulate the amount of equipment needed to retrieve and thaw solid ammonia chunks
		mass = 1.0 // Mass of equipment referenced above
		amount = 0.0
		temperature = -80
		loss_rate = 0.0000000000
		maxAmount = 0.0
		note = (requires insulation)
	}
}
// cl_large_nuclearEngine
// Using :Final tag to prevent the addition of ModuleHybridEngines
@PART[cl_large_nuclearEngine]:Final
{
    // Seems to be some issues when I add the new fuels to it so removing the hybrid part
	!MODULE[ModuleHybridEngines]{}
	MODULE
    {
		name = ModuleEngines
		thrustVectorTransformName = thrustTransform
		exhaustDamage = True
		ignitionThreshold = 0.1
		minThrust = 0
		maxThrust = 600
		PROPELLANT
		{
			name = LiquidH2
			ratio = 0.99999999999
		}
		PROPELLANT
		{
			name = nuclearFuel
			ratio = 0.00000000001
		}
		atmosphereCurve
		{
			key - 0 1100
			key = 1 494
		}
    }
    RESOURCE
    {

		name = nuclearFuel
		amount = 8
		maxAmount = 8
    }
    RESOURCE
    {

		name = nuclearWaste
		amount = 0
		maxAmount = 8
    }
	MODULE
	{
		name = ModuleEngineConfigs
		configuration = LiquidHydrogen
		modded = false		
		CONFIG
		{
			name = LiquidHydrogen
			thrustVectorTransformName = thrustTransform
			exhaustDamage = True
			ignitionThreshold = 0.1
			minThrust = 0
			maxThrust = 600
			PROPELLANT
			{
				name = LiquidH2
				ratio = 0.99999999999
				DrawGauge = True
			}
			PROPELLANT
			{
				name = nuclearFuel
				ratio = 0.00000000001
			}
			atmosphereCurve
			{
				key = 0 1100
				key = 1 543
			}		
		}				
		CONFIG
		{
			name = SlushHydrogen
			thrustVectorTransformName = thrustTransform
			exhaustDamage = True
			ignitionThreshold = 0.1
			minThrust = 0
			maxThrust = 600
			PROPELLANT
			{
				name = SlushH2
				ratio = 0.99999999998
				DrawGauge = True
			}
			PROPELLANT
			{
				name = nuclearFuel
				ratio = 0.00000000001
			}
			atmosphereCurve
			{
				key = 0 1100
				key = 1 543
			}		
		}				
		CONFIG
		{
			name = LiquidAmmonia
			thrustVectorTransformName = thrustTransform
			exhaustDamage = True
			ignitionThreshold = 0.1
			minThrust = 0
			maxThrust = 600
			PROPELLANT
			{
				name = LiquidAmmonia
				ratio = 0.99999999999
				DrawGauge = True
			}
			PROPELLANT
			{
				name = nuclearFuel
				ratio = 0.00000000001
			}
			atmosphereCurve
			{
				key = 0 630
				key = 1 312
			}		
		}				
		CONFIG
		{
			name = SolidAmmonia
			thrustVectorTransformName = thrustTransform
			exhaustDamage = True
			ignitionThreshold = 0.1
			minThrust = 0
			maxThrust = 600
			PROPELLANT
			{
				name = SolidAmmonia
				ratio = 0.99999999998
				DrawGauge = True
			}
			PROPELLANT
			{
				name = nuclearFuel
				ratio = 0.00000000001
			}
			atmosphereCurve
			{
				key = 0 630
				key = 1 312
			}		
		}				
	}
}
@PART[nuclearEngine]
{
    @MODULE[ModuleEngines]
    {
		@maxThrust = 333.6
		!PROPELLANT[LiquidFuel]
		!PROPELLANT[Oxidizer]
		PROPELLANT
		{
			name = LiquidH2
			ratio = 0.99999999998
		}
		PROPELLANT
		{
			name = nuclearFuel
			ratio = 0.00000000001
		}
		//@atmosphereCurve
		//{
		//	@key,0 = 0 1000
		//	@key,1 = 1 494
		//}
    }
    RESOURCE
    {

		name = nuclearWaste
		amount = 0
		maxAmount = 4
    }
	MODULE
	{
		name = ModuleEngineConfigs
		configuration = LiquidHydrogen
		modded = false		
		CONFIG
		{
			name = LiquidHydrogen
			thrustVectorTransformName = thrustTransform
			exhaustDamage = True
			ignitionThreshold = 0.1
			minThrust = 0
			maxThrust = 60
			PROPELLANT
			{
				name = LiquidH2
				ratio = 0.99999999998
				DrawGauge = True
			}
			PROPELLANT
			{
				name = nuclearFuel
				ratio = 0.00000000001
			}
			atmosphereCurve
			{
				key = 0 850
				key = 1 420
			}		
		}				
		CONFIG
		{
			name = SlushHydrogen
			thrustVectorTransformName = thrustTransform
			exhaustDamage = True
			ignitionThreshold = 0.1
			minThrust = 0
			maxThrust = 333.6
			PROPELLANT
			{
				name = SlushH2
				ratio = 0.99999999998
				DrawGauge = True
			}
			PROPELLANT
			{
				name = nuclearFuel
				ratio = 0.00000000001
			}
			atmosphereCurve
			{
				key = 0 1000
				key = 1 420
			}		
		}				
		CONFIG
		{
			name = LiquidAmmonia
			thrustVectorTransformName = thrustTransform
			exhaustDamage = True
			ignitionThreshold = 0.1
			minThrust = 0
			maxThrust = 333.6
			PROPELLANT
			{
				name = LiquidAmmonia
				ratio = 0.99999999998
				DrawGauge = True
			}
			PROPELLANT
			{
				name = nuclearFuel
				ratio = 0.00000000001
			}
			atmosphereCurve
			{
				key = 0 630
				key = 1 307
			}		
		}				
		CONFIG
		{
			name = SolidAmmonia
			thrustVectorTransformName = thrustTransform
			exhaustDamage = True
			ignitionThreshold = 0.1
			minThrust = 0
			maxThrust = 333.6
			PROPELLANT
			{
				name = SolidAmmonia
				ratio = 0.99999999998
				DrawGauge = True
			}
			PROPELLANT
			{
				name = nuclearFuel
				ratio = 0.00000000001
			}
			atmosphereCurve
			{
				key = 0 630
				key = 1 307
			}		
		}				
	}
}

Edited August 12, 2013 by Starwaster
fixed something in posted cfg

[RuBisCO]

Water would be plain dumb, it doesn't make a good propellant and it's too heavy. Unless it were an emergency and you could get some from an ocean. That would be interesting actually. "Lost on Laythe!". Not sure what other mods you'd need for that but you could hypothetically with the right mods set it up so you could totally do wilderness refueling.

IRL water is a very promising propellant, sure its performance would be about the same as LO2/LH2 systems, except water requires much simpler smaller fuel tanks and is relatively plentiful in the solar system. I've been experiment with modifications of the kethane mod so that Kethane is water and LO2 and LH2 require a lot of energy and time to manufacture from K-water, k-water directly minned and utilized in a nuclear engine on the other hand is a much better option. Of course the only propellant they could be made from water is H2O2 which as pretty poor ISP (~150), an RCS system that utilizes LH2 and LO2 is possible but is complex, better yet would be a "Resistojet" like system that utilizes water and electricity.

Again the Hydrogen boil off problem is lack of a cryocooler and uncoated metal fuel tanks in which protons can leak through, an appropriate in game solution should be a cryocooler.

Edited August 11, 2013 by RuBisCO

[The Lone Wolfling]

As I've said before, carry more H2 tanks. Bigger H2 tanks. lots and lots of H2 tanks!

And as I've said before, even with an infinite number of fuel tanks, a LV-909 engine always* ends up with more delta-v, mass for mass, than a LV-N in advanced fuels mode.

Advanced fuels is deeply broken currently. Due to the mass ratio difference, one should always* use the less advanced fuels - mass for mass they end up being a higher delta-v.

* With a single stage, that is.

[Starwaster]

IRL water is a very promising propellant, sure its performance would be about the same as LO2/LH2 systems, except water requires much simpler smaller fuel tanks and is relatively plentiful in the solar system. I've been experiment with modifications of the kethane mod so that Kethane is water and LO2 and LH2 require a lot of energy and time to manufacture from K-water, k-water directly minned and utilized in a nuclear engine on the other hand is a much better option. Of course the only propellant they could be made from water is H2O2 which as pretty poor ISP (~150), an RCS system that utilizes LH2 and LO2 is possible but is complex, better yet would be a "Resistojet" like system that utilizes water and electricity.

Again the Hydrogen boil off problem is lack of a cryocooler and uncoated metal fuel tanks in which protons can leak through, an appropriate in game solution should be a cryocooler.

The only way water is going to have performance 'about the same' as LO2/LH2 is if you break it up into and then liquefy it as LO2 and LH2. You've just made rocket fuel! That's not the same thing as saying that you are using water as a propellant. But you *CAN* use water as a propellant directly in a nuclear drive; it would have an ISP of approximately 412. Compare that to 850-1000 isp for H2. I'm not sure I would call that promising. But doable certainly.

And as I've said before, even with an infinite number of fuel tanks, a LV-909 engine always* ends up with more delta-v, mass for mass, than a LV-N in advanced fuels mode.

Advanced fuels is deeply broken currently. Due to the mass ratio difference, one should always* use the less advanced fuels - mass for mass they end up being a higher delta-v.

* With a single stage, that is.

Well then you're doing it wrong. No offense, I have no idea how you conducted your testing; either you didn't test a wide enough range of applications or you didn't make sure that your LV909 was actually receiving a mass of propellants that was even in the same ballpark as the LVN. I just conducted VERY exhaustive research with a keen eye to the possibility I was mistaken but that's not the case. Given an identical mass, the LV909 had a deltaV about 40% of the LVN. And that's with an engine whose stats are effectively that of a prototype.

The only time the LV909 even came CLOSE to the LVN was when I tested with very small tanks, probably because the pure H2 engine was receiving an overhead penalty

Sorry but you did not test 'mass for mass'

Edit: FYI, I used the stock LVN, not the modified one that I distributed here. However the fuels were tweaked to make them more accurate as they had all had their densities rounded because we can afford it in 'a game about little green men'. (I didn't agree so both LH2 and LO2 were brought to accurate densities)

Edited August 11, 2013 by Starwaster
clarification

[Kerbal01]

Anyone made a .cfg for bobcats soviet pack using RL Russian fuels?

[The Lone Wolfling]

Well then you're doing it wrong.

See here, down at the bottom. If I am doing it wrong, then please explain how so. You've mentioned modified configs, perhaps that is the reason why your tests are different.

[prometheanfire]

Does cryogenic fuel evaporate slower in space then it does on the ground (does atmospheric density effect the cryogenic evaporation rate)?

[Starwaster]

See here, down at the bottom. If I am doing it wrong, then please explain how so. You've mentioned modified configs, perhaps that is the reason why your tests are different.

As far as the configs go, both engines in question were unmodified during my testing. I made sure of that before testing and posting. Both LH2 and LO2 are using the following values. Original values for comparison. Difference is that H2 was rounded up and O2 rounded down.

@RESOURCE_DEFINITION[LiquidH2]
{
	@density = 0.0004428125
}
@RESOURCE_DEFINITION[LiquidOxygen]
{
	@density = 0.00713125
}

Originals

  name = LiquidH2
  density = 0.00045 // LH2 is super-light

RESOURCE_DEFINITION
  density = 0.007 // Liquid Oxygen is lighter than H2O2, but tends to give higher Isp
  flowMode = STACK_PRIORITY_SEARCH

As far as your referenced post and proofs, look, I like picking at the math of it too but at some point you have to get in there and and try the parts out and compare them in the game. It seems like you're trying to find a one size fits all formula for finding the best engine/best fuel configuration and it doesn't work that way. Some engine / fuel configurations work best at certain size levels of ships. I don't think that's accurately reflected. Also I think it depends on if you're prioritizing thrust over deltaV. In small ships I've made, performance was (in order of higher DV to lower) LF/LO2, LH2/LO2. While last, LH2/LO2 had much higher thrust probably because of its TWR.

With regards to the LVN, I thought I had covered all three fuel types but I'm not sure I looked at LF/OX so I'll have to go do that now.

[The Lone Wolfling]

[snip]

You want real-world testing? You've got real-world testing. Stock install + Kerbal Engineer Redux + MFS Real Fuels, these configs.

0.1t payload:

5 tons of launcher:

LV-909: LF/OX: 7,297 m/s, LF/O2: 6,646 m/s, H2/O2: 6,767 m/s

LV-N: 3,832 m/s

50 tons of launcher:

LV-909: LF/OX: 13,062 m/s, LF/O2: 9,995 m/s, 9,665 m/s

LV-N: 10,924 m/s

...Hey, look! Pretty much everything matches up with what I said in my earlier post!

...Are you sure that you tested this?

(In hindsight, sorry if I sound snippy, but I took quite a bit of time to test this before I made my previous post, and your response was simply "you're doing it wrong")

Edited August 12, 2013 by The Lone Wolfling

[Frederf]

I'm messing around with Kethane mod -> LiquidH2/LiquidOxygen conversion. I had no success with 0.75 despite updating the MF1.3 overload configs to match the 0.75 format (they didn't). Ke 0.76 drastically altered the config format so here's hoping that it'll actually make MF resources now.

Yay it works! Now I just need to find balanced values for the characteristics and I'll post them.

Edited August 12, 2013 by Frederf