[1.8+] Real Fuels

[klgraham1013]

Just a heads up, many of the parts now contain a small fuel tank for LiquidFuel (e.g. nacelleBody, radialEngineBosy, some cockpits), but this is not reflected in the overrides in RealFuels.

I did a quick thingie and the results are in. This is how I got that list, just in case it's missing something.

find . -name '*.cfg' -exec awk '/LiquidFuel/{ln1=NR;line1=$0} /amount/{ln2=NR;line2=$0} END{if(ln1&&ln2&&ln1 <ln2){print FILENAME, "\n", line1, "\n", line2}}' {} \;|sprunge

Also, doesn't appear Mk3 parts are updated. Made my self an MM config for all of these, but, you know...

Thanks for the speedy update during the holidays, by the way.

[NathanKell]

klgraham1013: those two things are related.

(i.e. mk3 configs when I have time or somebody sends a PR)

[Kitspace]

Is there a way to make an engine that would support more than one fuel configuration at a time?

Like the first run on the main launch vehicle fuel mixture as a booster stage and all subsequent ones on hypergolic fuel for maneuvers?

[Ralathon]

Is there a way to make an engine that would support more than one fuel configuration at a time?

Like the first run on the main launch vehicle fuel mixture as a booster stage and all subsequent ones on hypergolic fuel for maneuvers?

The trimodal NTR allows you to switch between H2 and hydrolox in flight. So it should be possible. Though you'd have to cook up the config file yourself.

[camlost]

RF is not working with tweakscale.

[NathanKell]

Again? Argh, thought I had it working. I'll fix it when I get back.

[velusip]

There's a long thread here, but perhaps someone can point me toward the rationale for setting the tank volumes as they are?

e.g. Most of the rocket fuel tank volumes seem to be merely multiplied by 5 to yield the realfuels volume. However the volume of spaceplane parts and adaptors are variable from 8.33 to 13.3. It doesn't seem to be related to crash strength or structure, part scaling, and I can't accurately calculate part volume, so I'm not sure why these values exist.

Anyway, a whole bunch of new tanks need to be added, and I'd be happy to help, but I just need info. Here's the incomplete chart I generated by parsing the stock files and comparing to the provided module manager changes:

                                    mono    O2   liquid  volume  crash    multi
"nacelleBody"                                        40
"radialEngineBody"                                   40

"adapterMk3-Size2Slant"                   1125     1375
"adapterMk3-Size2"                        1125     1375
"adapterSize2-Size1Slant"                  360      440
"adapterSize3-Mk3"                        1125     1375
"adapterSize2-Mk2"                         360      440
"adapterSize2-Size1"                       360      440
"adapterMk3-Mk2"                           900     1100

"fuelTank1-2"                             1440     1760  16000      6     x5
"miniFuelTank"                               5.735    7     62.5    6     x4.91
"fuelTankSmallFlat"                         45       55    500      6     x5
"fuelTankSmall"                             90      110   1000      6     x5
"fuelTank_long"                            360      440   4000      6     x5
"fuelTank4-2"                              360      440   4000      6     x5
"toroidalFuelTank"                          10       12.2  112.5    6     x5.07
"fuelTank"                                 180      220   2000            x5
"fuelTank3-2"                             2880     3520  32000            x5
"fuelTank2-2"                              720      880   8000            x5

"MK1Fuselage"                                       150   1900     20    x12.67
"mk3Fuselage" REMOVED
"mk3FuselageLF_50"                                 5000
"mk3FuselageLFO_25"                       1125     1375
"mk3FuselageLFO_100"                      4500     5500
"mk3FuselageLF_25"                                 2500
"mk3FuselageLF_100"                               10000
"mk3FuselageLFO_50"                       2250     2750

"mk3FuselageMONO"                   1000
"mk2FuselageShortLFO"                      135      165   3600      50    x12
"mk2FuselageShortLiquid"                            300   2500      50     x8.33 
"mk2Fuselage"                                       600   5000      50     x8.33 
"mk2FuselageLongLFO"                       270      330   7200      50    x12
"mk2_1m_Bicoupler"                         135      165   4000      50    x13.33 
"mk2_1m_AdapterLong"                       225      275   5900            x11.8
"mk2_1m_Adapter" REMOVED
"mk2DockingPort" REMOVED
"mk2pit_Standard" REMOVED*
"mk2Cockpit_Standard"                 15                            45
"mk2pit_Inline" REMOVED*
"mk2Cockpit_Inline"                   25
"mk2SpacePlaneAdapter"                     135      165   3000            x10
"mk2FuselageShortMono"               300                  3600            x12

Edited December 26, 2014 by velusip
added other half of chart

[Starwaster]

There's a long thread here, but perhaps someone can point me toward the rationale for setting the tank volumes as they are?

e.g. Most of the rocket fuel tank volumes seem to be merely multiplied by 5 to yield the realfuels volume. However the volume of spaceplane parts and adaptors are variable from 8.33 to 13.3. It doesn't seem to be related to crash strength or structure, part scaling, and I can't accurately calculate part volume, so I'm not sure why these values exist.

Anyway, a whole bunch of new tanks need to be added, and I'd be happy to help, but I just need info. Here's the incomplete chart I generated by parsing the stock files and comparing to the provided module manager changes:

Real Fuel volume units are in liters. Most parts volume in liters can be found by multiplying the stock value by 5. Pressurized tanks such as those containing gaseous xenon have larger sizes because that is the volume of the gas uncompressed. If there's any deviation from the stock volume x5 then it's because someone felt that the new volume was a more realistic value. Again, in liters.

[NathanKell]

The problem is that tanks, in KSP, aren't actually tanks. They're stages, with tanks inside.

Check out this cutaway view of the Titan II GLV. Notice how there are capsule tanks inside each stage. The issue is that you need to estimate, for a given part, how much of the part's volume can actually be utilized by tanks, assuming two capsule tanks. You can see that the longer (higher aspect ratio height : width) lower stage has more of its volume utilized in tankage, compared to the upper stage.

Now, it so happens that one gets a reasonable utilized-volume figure for most KSP tanks by multiplying their LF+Ox contents by five. But it would be the best, long term, to actually go through the parts and figure out the above. Since the users of RF however will often use procedural parts or (in the case of RO) real life rockets' parts (for which we know the tank sizes), it hasn't seemed worth the effort to recalculate volumes, with the exception of spaceplane parts where stock volumes are bonkers.

[Starwaster]

The problem is that tanks, in KSP, aren't actually tanks. They're stages, with tanks inside.

Check out this cutaway view of the Titan II GLV. Notice how there are capsule tanks inside each stage. The issue is that you need to estimate, for a given part, how much of the part's volume can actually be utilized by tanks, assuming two capsule tanks. You can see that the longer (higher aspect ratio height : width) lower stage has more of its volume utilized in tankage, compared to the upper stage.

Now, it so happens that one gets a reasonable utilized-volume figure for most KSP tanks by multiplying their LF+Ox contents by five. But it would be the best, long term, to actually go through the parts and figure out the above. Since the users of RF however will often use procedural parts or (in the case of RO) real life rockets' parts (for which we know the tank sizes), it hasn't seemed worth the effort to recalculate volumes, with the exception of spaceplane parts where stock volumes are bonkers.

Yeah except that we're treating everything as if it has common bulkheads.

[BLUAV8R]

Can a part have an engine and resources with real fuels? Mine will hold resources and say it has an engine, but when I click to add the fuel type it uses it adds it, but the Delta V readout is 0 and if I launch it the engines say "LqdOxygen or LqdHydrogen deprived!" even though there is about 30KL of it IN the part itself.... I'm getting confus over here and could use help

Here is the part parameters:

PART
{
// --- general parameters ---
name = AresVCore
module = Part
author = BobCat/YANFRET/edits by me

// --- asset parameters ---
mesh = model.mu


MODEL
{
  model = CMES/Ares_V/Ares_V_Core/model
  scale = 1.237, 1.2, 1.237
}

scale = 1
rescaleFactor = 0.765


CoMOffset = 0, -20.0, 0

// --- node definitions ---
node_stack_top = 0.0, 1.6518588, 0.0, 0.0, 1.0, 0.0, 3
node_stack_bottom = 0.0, -41.0, 0.0, 0.0, 1.0, 0.0, 3



fx_exhaustFlame_blue = 0.0, -3.0, 0.0, 0.0, 1.0, 0.0, running
fx_exhaustLight_blue = 0.0, -3.0, 0.0, 0.0, 0.0, 1.0, running
fx_smokeTrail_light  = 0.0, -3.0, 0.0, 0.0, 1.0, 0.0, running



sound_rocket_hard = running
sound_vent_soft = disengage
sound_explosion_low = flameout



// --- editor parameters ---

TechRequired = veryHeavyRocketry
entryCost = 40000
cost = 13900
category = Propulsion
subcategory = 0
title = Ares V Main Core
manufacturer = Aerojet Kerbodyne
description =  One of the largest launch vehicles around, this booster was made to bring huge cargo into LKO or beyond.

// attachment rules: stack, srfAttach, allowStack, allowSrfAttach, allowCollision
attachRules = 1,0,1,1,0

// --- standard part parameters ---
mass = 12
dragModelType = default
maximum_drag = 0.2
minimum_drag = 0.2
angularDrag = 2
crashTolerance = 200
maxTemp = 2900
breakingForce = 99200
breakingTorque = 99200

// Tank Parameters

MODULE
{
	name = ModuleFuelTanks
	volume = 304000
	type = Default
}

MODULE
{
	name = ModuleEngines
	thrustVectorTransformName = thrustTransform
	exhaustDamage = True
	ignitionThreshold = 0.1
	minThrust = 0
	maxThrust = 4560
	heatProduction = 220
	fxOffset = 0, 0, 2.5
	PROPELLANT
	{
		name = Kerosene
		ratio = 37.694087
		DrawGauge = True
	}
	PROPELLANT
	{
	   name = LqdOxygen
	   ratio = 62.305913
	}
	atmosphereCurve
 	{
		key = 0 368
		key = 1 304
 	}
}

MODULE
{
	name = ModuleEngineConfigs
	type = ModuleEngines
	techLevel = 7
	origTechLevel = 7
	engineType = L
	origMass = 12
	configuration = Kerosene+LqdOxygen
	modded = false
	CONFIG
	{
		name = LqdHydrogen+LqdOxygen
		maxThrust = 4560
		heatProduction = 217

		PROPELLANT
		{
			name = LqdHydrogen
			ratio = 0.7630831
			DrawGauge = True
		}
		PROPELLANT
		{
			name = LqdOxygen
			ratio = 0.2369169
		}
		IspSL = 1.3
		IspV = 1.27
		throttle = 0

		ModuleEngineIgnitor
		{
			name = ModuleEngineIgnitor
			ignitionsAvailable = 1
			autoIgnitionTemperature = 800
			ignitorType = Electric
			useUllageSimulation = true
			IGNITOR_RESOURCE
			{
				name = ElectricCharge
				amount = 32
			}
		}
	}
	CONFIG
	{
		name = Kerosene+LqdOxygen
		maxThrust = 4560
		heatProduction = 217

		PROPELLANT
		{
			name = Kerosene
			ratio = 0.37694087
			DrawGauge = True
		}
		PROPELLANT
		{
			name = LqdOxygen
			ratio = 0.62305913
		}
		IspSL = 1
		IspV = 1
		throttle = 0

		ModuleEngineIgnitor
		{
			name = ModuleEngineIgnitor
			ignitionsAvailable = 1
			autoIgnitionTemperature = 800
			ignitorType = Electric
			useUllageSimulation = true
			IGNITOR_RESOURCE
			{
				name = ElectricCharge
				amount = 32
			}
		}
	}
	CONFIG
	{
		name = Aerozine50+NTO
		maxThrust = 4560
		heatProduction = 217

		PROPELLANT
		{
			name = Aerozine50
			ratio = 0.5017301
			DrawGauge = True
		}
		PROPELLANT
		{
			name = NTO
			ratio = 0.4982699
		}
		IspSL = 0.96
		IspV = 0.95
		throttle = 0

		ModuleEngineIgnitor
		{
			name = ModuleEngineIgnitor
			ignitionsAvailable = 1
			autoIgnitionTemperature = 800
			ignitorType = Electric
			useUllageSimulation = true
			IGNITOR_RESOURCE
			{
				name = ElectricCharge
				amount = 32
			}
		}
	}
}

MODULE
{
	name = ModuleGimbal
	gimbalTransformName = thrustTransform
	gimbalRange = 3
}

MODULE
{
	name = ModuleAnimateHeat
	ThermalAnim = overheat2
}

MODULE
{
	name = ModuleAlternator	
	RESOURCE
	{
		name = ElectricCharge
		rate = 12.0
	}
}

RESOURCE
{
	name = ElectricCharge
	amount = 0
	maxAmount = 0
  	isTweakable = false
	hideFlow = true
}

Anybody see anything blatantly obvious?

EDIT: So i've been looking at stock parts that do this (like the LFB in NASAMission) and it added "basemass = -1" under the MFT module, testing now...

Edited December 26, 2014 by Sippyfrog

[Starwaster]

Can a part have an engine and resources with real fuels? Mine will hold resources and say it has an engine, but when I click to add the fuel type it uses it adds it, but the Delta V readout is 0 and if I launch it the engines say "LqdOxygen or LqdHydrogen deprived!" even though there is about 30KL of it IN the part itself.... I'm getting confus over here and could use help

Anybody see anything blatantly obvious?

EDIT: So i've been looking at stock parts that do this (like the LFB in NASAMission) and it added "basemass = -1" under the MFT module, testing now...

No, it's possible to do, that's how SRB's work.... I'll look over your part config. Right off the top though, you're missing a bracket in the config you posted, at the end. (to close the part)

Edit: No, basemass = -1 isn't the reason. You do want that, in all probability, but what it does is tell RF to use the part's mass instead of calculating the tank mass. That way, if you're recreating a historical part, it will be accurate as far as mass goes. (of course, if you change the tankage from what the stage had historically, then it wont be realistic)

Edited December 26, 2014 by Starwaster

[BLUAV8R]

No, it's possible to do, that's how SRB's work.... I'll look over your part config. Right off the top though, you're missing a bracket in the config you posted, at the end. (to close the part)

Edit: No, basemass = -1 isn't the reason. You do want that, in all probability, but what it does is tell RF to use the part's mass instead of calculating the tank mass. That way, if you're recreating a historical part, it will be accurate as far as mass goes. (of course, if you change the tankage from what the stage had historically, then it wont be realistic)

I've made.. progress... I got it to actually get fuel now, but I have to manually enter the fuel numbers into the Tank GUI, there's not button to auto do it according to the engine it's feeding () So for testing of other features, I just did RESOURCE with blah blah blah of the stuff,

I still wanna make it a MFT, but I dont wanna have to manually type in the correct numbers each time I load the tank from the part list in the editor, do you know what I have to do?

EDIT: here's what I got so far:

PART
{
// --- general parameters ---
name = AresVCore
module = Part
author = BobCat/YANFRET/edits by me

// --- asset parameters ---
mesh = model.mu


MODEL
{
  model = CMES/Ares_V/Ares_V_Core/model
  scale = 1.237, 1.2, 1.237
}

scale = 1
rescaleFactor = 0.765


CoMOffset = 0, -20.0, 0

// --- node definitions ---
node_stack_top = 0.0, 1.6518588, 0.0, 0.0, 1.0, 0.0, 3
node_stack_bottom = 0.0, -41.0, 0.0, 0.0, 1.0, 0.0, 3



fx_exhaustFlame_blue = 0.0, -3.0, 0.0, 0.0, 1.0, 0.0, running
fx_exhaustLight_blue = 0.0, -3.0, 0.0, 0.0, 0.0, 1.0, running
fx_smokeTrail_light  = 0.0, -3.0, 0.0, 0.0, 1.0, 0.0, running



sound_rocket_hard = running
sound_vent_soft = disengage
sound_explosion_low = flameout



// --- editor parameters ---

TechRequired = veryHeavyRocketry
entryCost = 40000
cost = 13900
category = Propulsion
subcategory = 0
title = Ares V Main Core
manufacturer = Aerojet Kerbodyne
description =  One of the largest launch vehicles around, this booster was made to bring huge cargo into LKO or beyond.

// attachment rules: stack, srfAttach, allowStack, allowSrfAttach, allowCollision
attachRules = 1,0,1,1,0

// --- standard part parameters ---
mass = 12
dragModelType = default
maximum_drag = 0.2
minimum_drag = 0.2
angularDrag = 2
crashTolerance = 200
maxTemp = 2900
breakingForce = 99200
breakingTorque = 99200

// Tank Parameters

MODULE
{
	name = ModuleEngines
	thrustVectorTransformName = thrustTransform
	exhaustDamage = True
	ignitionThreshold = 0.1
	minThrust = 0
	maxThrust = 4560
	heatProduction = 220
	fxOffset = 0, 0, 2.5
	PROPELLANT
	{
		name = Kerosene
		ratio = 37.694087
		DrawGauge = True
	}
	PROPELLANT
	{
	   name = LqdOxygen
	   ratio = 62.305913
	}
	atmosphereCurve
 	{
		key = 0 368
		key = 1 304
 	}
}

MODULE
{
	name = ModuleEngineConfigs
	type = ModuleEngines
	techLevel = 7
	origTechLevel = 7
	engineType = L
	origMass = 12
	configuration = LqdHydrogen+LqdOxygen
	modded = false
	CONFIG
	{
		name = LqdHydrogen+LqdOxygen
		maxThrust = 4560
		heatProduction = 217

		PROPELLANT
		{
			name = LqdHydrogen
			ratio = 0.7630831
			DrawGauge = True
		}
		PROPELLANT
		{
			name = LqdOxygen
			ratio = 0.2369169
		}
		IspSL = 1.3
		IspV = 1.27
		throttle = 0

		ModuleEngineIgnitor
		{
			name = ModuleEngineIgnitor
			ignitionsAvailable = 1
			autoIgnitionTemperature = 800
			ignitorType = Electric
			useUllageSimulation = true
			IGNITOR_RESOURCE
			{
				name = ElectricCharge
				amount = 32
			}
		}
	}
}

MODULE
{
	name = ModuleFuelTanks
	volume = 304000
	type = Cryogenic
}

MODULE
{
	name = ModuleGimbal
	gimbalTransformName = thrustTransform
	gimbalRange = 3
}

MODULE
{
	name = ModuleAnimateHeat
	ThermalAnim = overheat2
}

MODULE
{
	name = ModuleAlternator	
	RESOURCE
	{
		name = ElectricCharge
		rate = 12.0
	}
}

RESOURCE
{
	name = ElectricCharge
	amount = 0
	maxAmount = 0
  	isTweakable = false
	hideFlow = true
}

}

[StoryMusgrave]

In my experience, RealFuels isn't 'self-aware' of Engines within the same part. When they are on separate parts, you can click and add fuel by engine no problem. The same part though it doesn't 'see' it.

I haven't tested it...but MAYBE one just needs the ModuleFuelTanks MODULE after ModuleEngineConfigs.

[BLUAV8R]

In my experience, RealFuels isn't 'self-aware' of Engines within the same part. When they are on separate parts, you can click and add fuel by engine no problem. The same part though it doesn't 'see' it.

I haven't tested it...but MAYBE one just needs the ModuleFuelTanks MODULE after ModuleEngineConfigs.

Yeah that's what I thought lol XD I tried that to see and am looking now, KSP just booted

EDIT: meh same results, maybe that's something to be addressed in future versions @Nathankell?

Parts with an engine AND MFT (bi propellant is the problem really) doesn't prompt the ability to auto fill the tank to the correct proportions that the engine needs

Edited December 26, 2014 by Sippyfrog

[BLUAV8R]

Yeah that's what I thought lol XD I tried that to see and am looking now, KSP just booted

EDIT: meh same results, maybe that's something to be addressed in future versions @Nathankell?

Parts with an engine AND MFT (bi propellant is the problem really) doesn't prompt the ability to auto fill the tank to the correct proportions that the engine needs

Okay, wait, I got it to work..... not too sure what I did lol

Final Config:

PART
{
// --- general parameters ---
name = AresVCore
module = Part
author = BobCat/YANFRET/edits by me

// --- asset parameters ---
mesh = model.mu


MODEL
{
  model = CMES/Ares_V/Ares_V_Core/model
  scale = 1.237, 1.2, 1.237
}

scale = 1
rescaleFactor = 0.765


CoMOffset = 0, -20.0, 0

// --- node definitions ---
node_stack_top = 0.0, 1.6518588, 0.0, 0.0, 1.0, 0.0, 3
node_stack_bottom = 0.0, -41.0, 0.0, 0.0, 1.0, 0.0, 3



fx_exhaustFlame_blue = 0.0, -3.0, 0.0, 0.0, 1.0, 0.0, running
fx_exhaustLight_blue = 0.0, -3.0, 0.0, 0.0, 0.0, 1.0, running
fx_smokeTrail_light  = 0.0, -3.0, 0.0, 0.0, 1.0, 0.0, running



sound_rocket_hard = running
sound_vent_soft = disengage
sound_explosion_low = flameout



// --- editor parameters ---

TechRequired = veryHeavyRocketry
entryCost = 40000
cost = 13900
category = Propulsion
subcategory = 0
title = Ares V Main Core
manufacturer = Aerojet Kerbodyne
description =  One of the largest launch vehicles around, this booster was made to bring huge cargo into LKO or beyond.

// attachment rules: stack, srfAttach, allowStack, allowSrfAttach, allowCollision
attachRules = 1,0,1,1,0

// --- standard part parameters ---
mass = 12
dragModelType = default
maximum_drag = 0.2
minimum_drag = 0.2
angularDrag = 2
crashTolerance = 200
maxTemp = 2900
breakingForce = 99200
breakingTorque = 99200

// Tank Parameters

MODULE
{
	name = ModuleEngines
	thrustVectorTransformName = thrustTransform
	exhaustDamage = True
	ignitionThreshold = 0.1
	minThrust = 0
	maxThrust = 4560
	heatProduction = 220
	fxOffset = 0, 0, 2.5
	PROPELLANT
	{
		name = Kerosene
		ratio = 37.694087
		DrawGauge = True
	}
	PROPELLANT
	{
	   name = LqdOxygen
	   ratio = 62.305913
	}
	atmosphereCurve
 	{
		key = 0 368
		key = 1 304
 	}
}

MODULE
{
	name = ModuleEngineConfigs
	type = ModuleEngines
	techLevel = 7
	origTechLevel = 7
	engineType = L
	origMass = 12
	configuration = LqdHydrogen+LqdOxygen
	modded = false
	CONFIG
	{
		name = LqdHydrogen+LqdOxygen
		maxThrust = 4560
		heatProduction = 217

		PROPELLANT
		{
			name = LqdHydrogen
			ratio = 0.7630831
			DrawGauge = True
		}
		PROPELLANT
		{
			name = LqdOxygen
			ratio = 0.2369169
		}
		IspSL = 1.3
		IspV = 1.27
		throttle = 0

		ModuleEngineIgnitor
		{
			name = ModuleEngineIgnitor
			ignitionsAvailable = 1
			autoIgnitionTemperature = 800
			ignitorType = Electric
			useUllageSimulation = true
			IGNITOR_RESOURCE
			{
				name = ElectricCharge
				amount = 32
			}
		}
	}
}

MODULE
{
	name = ModuleFuelTanks
	volume = 304000
	type = Cryogenic
}

MODULE
{
	name = ModuleGimbal
	gimbalTransformName = thrustTransform
	gimbalRange = 3
}

MODULE
{
	name = ModuleAnimateHeat
	ThermalAnim = overheat2
}

MODULE
{
	name = ModuleAlternator	
	RESOURCE
	{
		name = ElectricCharge
		rate = 12.0
	}
}

RESOURCE
{
	name = ElectricCharge
	amount = 0
	maxAmount = 0
  	isTweakable = false
	hideFlow = true
}

}

[Starwaster]

Uhm yeah that bit about not recognizing the engine when they're on the same part isn't true. I'm not sure it was ever true

(Sippy: sorry, didn't get to look at that yet, glad you got it working)

[StoryMusgrave]

Uhm yeah that bit about not recognizing the engine when they're on the same part isn't true. I'm not sure it was ever true

(Sippy: sorry, didn't get to look at that yet, glad you got it working)

Um, yeah, it WAS true. IF things are not in 'proper' order.

I haven't tested it...but MAYBE one just needs the ModuleFuelTanks MODULE after ModuleEngineConfigs.

Seems under Sippy's own testing. Put MFT before engine on the same part...no worky...put it after...worky.

Edited December 27, 2014 by StoryMusgrave

[velusip]

...spaceplane parts where stock volumes are bonkers.

When you say stock volumes are bonkers you mean they are too high? In that case, why are the few existing RF volume configurations for plane parts generated with such a high multiplier? Or did you mean that the stock volumes are too low and required a higher multiplier to account for all the empty space?

I'd like to fill in the blanks in the RF volume config for all these new stock parts. I just need to know some of the rationale that went into the plane parts which already have RF volumes defined (mk2Fuselage, et cetrea).

I tried using some Blender plugins to calculate volume in the stock parts as a starting point. I will then subtract volume based on some assumed/imagined internal structure based on the stock crash strength, and further subtract what other systems might occupy the part internals (cockpit, life support, electronics, pumps, solenoids/servos, et cetera). Since several of the models are poorly made, I can't get an accurate volume from Blender (perhaps someone else has more experience summarizing subtractive geometry to yield fine detail). In the meantime I will just overlay simple geometry and add up an approximate volume.

[Buzzer]

post deleted

Edited December 30, 2014 by Buzzer
posted in the wrong topic

[Camacha]

The Tank Type selection in the rightclick menu is coming from RealFuels, right? Is there a description anywhere what each type entails?

Edit: I understood thrust varies with Isp with RealFuels. I just installed it to test that, but thrust stays at 200, even though iSP does seem to vary. Am I missing something? I see the fuel flow decreasing with increasing iSP, that looks an awful lot like stock behaviour.

Edited December 30, 2014 by Camacha

[Starwaster]

The Tank Type selection in the rightclick menu is coming from RealFuels, right? Is there a description anywhere what each type entails?

Edit: I understood thrust varies with Isp with RealFuels. I just installed it to test that, but thrust stays at 200, even though iSP does seem to vary. Am I missing something? I see the fuel flow decreasing with increasing iSP, that looks an awful lot like stock behaviour.

Sounds like it's not installed properly.

Logs.

http://forum.kerbalspaceprogram.com/threads/92229-VALUABLE-LINK-FOR-FINDING-LOGS

[Camacha]

I should learn to follow instructions, I neglected to install an engine pack. Stay in school, kids.

Edited December 30, 2014 by Camacha

[Starwaster]

I should learn to follow instructions, I neglected to install an engine pack. Stay in school, kids.

Hukt on rokkit siunce werkt fer mee.

[Northstar1989]

The problem is that tanks, in KSP, aren't actually tanks. They're stages, with tanks inside.

Check out this cutaway view of the Titan II GLV. Notice how there are capsule tanks inside each stage. The issue is that you need to estimate, for a given part, how much of the part's volume can actually be utilized by tanks, assuming two capsule tanks. You can see that the longer (higher aspect ratio height : width) lower stage has more of its volume utilized in tankage, compared to the upper stage.

Now, it so happens that one gets a reasonable utilized-volume figure for most KSP tanks by multiplying their LF+Ox contents by five. But it would be the best, long term, to actually go through the parts and figure out the above. Since the users of RF however will often use procedural parts or (in the case of RO) real life rockets' parts (for which we know the tank sizes), it hasn't seemed worth the effort to recalculate volumes, with the exception of spaceplane parts where stock volumes are bonkers.

Good insight as always. We're missing one MAJOR feature of real-world fuel tanks though (well, one more besides the problems I mentioned with how the Square-Cube Law affects boil-off before...)

Pressurized Fuel Tanks. That is, stages that have fuel tanks sufficiently pressurized that their fuel volume capacity actually exceeds what could be held at 1 atmosphere of pressure.

This mainly holds true of Service Modules (which can reach an average utilization of 400%, 500% or more compared to tanks a 1 atmosphere- through high pressurization), but also would likely hold true of spaceplane parts (although with the volume factors reaching as high as 13x the LFO capacity for existing spaceplane parts in KSP, it seems that a roughly 3 atm pressure level with less than 100% space utilization is already accounted for...)

This mainly affects Service Module parts from the Procedural Parts mod, but also affects a few mod "Service Module" parts such as the NovaPunch2 "Yawmaster Service Module". All of these parts have MUCH lower volume capacities than they should for their size, as real life service modules often exceed 400% utilization (and can reach 500% or more) compared to 1 atm through highly pressurizing the fuel tanks. Even ordinary fuel tanks are often pressurized- the Space Shuttle External Fuel Tank was pressurized to 1.5 atm, for example...

The mass of the fuel tanks should be scaled with the volume capacity- i.e. a Procedural Parts Service Module with 500% utilization should have slightly more than 5x the tank mass of a BalloonCryo tank of the same size (Service Module tanks are also insulated in Procedural Parts, and there doesn't seem to be a way to create Service Modules with uninsulated pressurized fuel tanks for hypergolic...) I say *more than* 5x the tank mass because service modules often include more structural mass than standard fuel tanks in real life (the Procedural Parts mod already accounts for this with an inferior mass-fraction).

The primary advantage of service modules is that they hold a lot more fuel mass for their physical size due to pressurization (thus creating a much more compact aerodynamic profile with a higher ballistic-coefficient, or fitting inside smaller fairings, among other benefits) but strangely, this advantage is NOT reflected in the Procedural Parts or NovaPunch2 mods- making them just heavy fuel tanks with inferior mass-ratios compared to all the other fuel tank types (they do have the capability to store ElectricCharge, but this is only a minor benefit for their much higher mass...) There is no easy way to simulate the other main benefit of pressurization in KSP besides a higher space utilization- the ability to efficiently use pressure-fed engines that are simpler/cheaper/lighter to design and manufacture compared to those relying on turbopumps...

Regards,

Northstar

P.S. Turns out that fuel tanks are often even more highly pressurized than I thought. Any pressure-fed rocket engine requires *higher* tank pressure than chamber pressure, and the Kestrel pressure-fed rocket engine of the Falcon 1 had a chamber pressure of 930 kPa (9.18 atm), for instance. Which means, the fuel tanks of the Falcon 1 upper stage were pressurized to at least 930 kPa as well...

Edited January 2, 2015 by Northstar1989