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

[8749236]

Question: What does Nuclear Waste do and how do we deal with them?

Just throw them away?

[SchroedingersHat]

Question: What does Nuclear Waste do and how do we deal with them?

Just throw them away?

It does nothing and you can't get rid of it. The thing it is modelling is your nuclear engine has a big lump of uranium/plutonium/whatever; as it decays some of it turns into other elements/isotopes and is no longer fissile (but is still largely part of the same lump of mostly-metal).

Once it is all gone the engine would require reassembly with new fuel.

I wouldn't worry about it too much as you're unlikely to run out.

- Isp will affect thrust instead of fuel consumption

If you are going to be implementing a system for altering thrust, might I request the addition of a velocity/pressure 2d curve for jet engines?

Something like:

        thrustCurve
        {
            pKey =        1 0.1 0.01    0 // Pressures as fractions of sea level pressure on Kerbin
            vkey =   0    1 0.5  0.2  0.1 // A velocity followed by the thrust multiplier at each of the pressures listed
            vkey = 500 0.67 0.3  0.1 0.05 // As above
            vkey = 550 0.44 0.1 0.04 0.01
            vkey = 605   0   0    0    0
        }

Then the same for Isp

The alternative would be some kind of 2d table (much easier to read/edit) but I don't know if that's possible.

Either way, I believe making max thrust a function of pressure and velocity and Isp an independant function of pressure and velocity should allow for much more realistic air-breathing engines (as opposed to the current state where Isp is a function of pressure and velocity (because the velocitycurve modifies thrust and not fuel use) and thrust is a function of velocity). Then I can do some reading and fiddle with nasa engine sim and learn what parameters to actually set (or Ferram or Taverius or someone can use their existing knowledge to do it much more efficiently)

[Chestburster]

UH25 and Aerozine 50 are both different mixtures of Hydrazine and UDMH, ones 25 to 75 mix and other is 50/50, dunno if its even possible make a 3rd mixture set so you can mix hypergolic fuels to get different types of ISP/Trust types..

I could add every possible mixture but does it make sense to have every possible configuration aviable? Since every nation is using different mixtures, what should our Kerbals use?

[SchroedingersHat]

I could add every possible mixture but does it make sense to have every possible configuration aviable? Since every nation is using different mixtures, what should our Kerbals use?

As far as I know, MMH and UDMH are usually added to make it slightly safer, improve cooling, and will (marginally) decrease density and Isp of the fuel. None of these things sound very Kerbal and the heat system isn't that complicated (yet?) so my thought would be to just have 'hydrazine' and leave it at that.

[cardajowol]

I could add every possible mixture but does it make sense to have every possible configuration aviable? Since every nation is using different mixtures, what should our Kerbals use?

From what I remember that the Apollo Service Module used Aerozine 50 and nitrogen Tetrioxide

The engine used was an AJ10-137 engine[6] using Aerozine 50 as fuel and nitrogen tetroxide (N2O4) as oxidizer.

- More Kerbal Safe?

[CoriW]

I'm having a little bit of trouble with the installation of this, I mean the "ModularFuelTanks" folder and "ModuleManager.dll" both go into the "GameData" folder, but where do I put the contents of the "RealFuels.zip"? Does it go into the "GameData" folder or "ModularFuelTanks" folder?

EDIT: Alright so it looks like putting the contents of "RealFuels.zip" into the "GameData" folder worked.

Edited July 24, 2013 by CoriW

[Chestburster]

You should put it into the ModularFuelTanks folder, but it doesnt realy matter since R comes after M (ModuleManager goes alphabeticaly through your gamedata).

[8749236]

It does nothing and you can't get rid of it. The thing it is modelling is your nuclear engine has a big lump of uranium/plutonium/whatever; as it decays some of it turns into other elements/isotopes and is no longer fissile (but is still largely part of the same lump of mostly-metal).

Once it is all gone the engine would require reassembly with new fuel.

I wouldn't worry about it too much as you're unlikely to run out.

I would like a jettison pod so I can get rid of it =D

(Punch it into space would be fine =D or use it as a bomb or something...)

Btw, if I do not have space for nuclear Waste, does my engine gonna run ( i can't play games right now =( )

[Chestburster]

Your engines will still run (before i added the empty waste they didn't store it at all) if the waste is full, but the nuclear fuel and waste are balanced.. if you run out of nuclear fuel, your waste will also be filled and your engine is dead.

[CoriW]

You should put it into the ModularFuelTanks folder, but it doesnt realy matter since R comes after M (ModuleManager goes alphabeticaly through your gamedata).

Ah thanks for that, I really wasn't all that sure about it.

Anyways, I've been messing around with the plugin and some questions have come up, so I suppose now is the best time to ask them.

1) Why does the "LV-T30 Liquid Fuel Engine" not support the use of LiquidFuel + LiquidOxygen, or LiquidH2 + LiquidOxygen mixtures, while it's counterpart the "LV-T45 Liquid Fuel Engine" supports both?

2) Why do the "Rockomax "Mainsail" Liquid Engine" and "Rockomax "Skipper" Liquid Engine" not support the use of LiquidH2 + LiquidOxygen mixture?

All of the other engines seem to support all 3 mixtures of LiquidFuel + Oxidizer, LiquidFuel + LiquidOxygen, and LiquidH2 + LiquidOxygen, which is why I was curious about these ones, especially curious about the "LV-T30 Liquid Fuel Engine", which seems like it may just be a mistake?

P.S - Actually, while I'm asking questions, does the ".git" folder actually do anything...? I've been deleting all the useless folders and files like those "Source" folders and ".DS_Store" files since they don't actually do anything and there's no real reason to keep them. Was wondering if the ".git" folder falls into that category?

[Chestburster]

That isn't an oversight; the T30 is the "dead simple" model, and thus doesn't have any switchable configurations.

In the next version, it will have a ModuleEngineConfigs, but it won't have any alternate configurations.

And about the two others.. don't know, didn't touch them so its by design. I think the reason is "brute force" and LH2+LOX isn't for "brute force" since that mixture has decreased thrust (LF+LOX is your first stage fuel). With the upcomming version i'm going to take a second look at all engines, adjusting ISP, mixtures and fixing bugs if i find them.

[RuBisCO]

Again on my cryocooler fix: anyone make a cryocooler part yet?

[Chimer4]

Ignore, went full derp and only realized once I made this post. Sorry!

Edited July 24, 2013 by Chimer4

[cardajowol]

Any idea if this is broke in .21?

[Uhd]

Any idea if this is broke in .21?

I have played a bit with .21 and it seems like things are working as expected with this mod (including the "advanced version"/real fuels). It is missing some definitions for the new fuel tanks and engines though.

[rpayne88]

Just a few questions:

1. How do you install this mod? I've downloaded and unzipped it, but I have no idea where to put everything. I'm used to the gamedata parts or pluggins system of installing mods (easiest way I could describe it.)

2. Can cryogenic fuel be prevented from evaporating at a certain temperature. I'd believe that since space is cold and the fuel needs to remain cold, that at a certain point it would stop evaporating.

3. Is this 0.21 compliant?

Sorry if this has already been asked, I don't have time to read through 32 pages of this thread.

[Starwaster]

Just a few questions:

2. Can cryogenic fuel be prevented from evaporating at a certain temperature. I'd believe that since space is cold and the fuel needs to remain cold, that at a certain point it would stop evaporating.

Space doesn't have a temperature. You can only measure temperature if you have mass, something to be hot or cold. In point of fact, with space vehicles, keeping cool is the main concern. The reason is that you have all these sources of heat (sunlight, equipment, computers, etc) that can only be shed by radiating back into space.

[AngelLestat]

I fail to get any benefit using hydrogen or nerva engines.

So there are 3 options.

-I am doing something wrong.

-My instalation is not ok.

-Something is wrong in the parameters.

I want to believe that is one of the first two.

I am testing with 0.21 ksp version and I add the 1.3 modular fuel system in advance with the last Chestburster parameters with nova punch mod.

This is one rocket:

subir imagenes gratis

subir imagenes gratis

You can see that I am using the nerva engine from nova punch (I also did the same test with 4 original nerva engines)

The 2 orange tanks has full hidrogen, the cone tank has oxigen.

The solid booster reach 15 km, So I start burning H2+oxigen, then when the oxigen is out I change to full H2.

And with all that, I can not enter in orbit around mun.

Something is very wrong there.

Nerva engines had a ISP of 900 in vaccum. But the fuel drop very fast still.

I can get more delta V with a 1/10 of the fuel without using hidrogen or nuclear engines. So.. what I am doing wrong?

When I install this mod, I unzip the fuel.zip that comes with the mod, and then I unzip the chestburster config file remplacing all the others.

[Morrigi]

Space doesn't have a temperature. You can only measure temperature if you have mass, something to be hot or cold. In point of fact, with space vehicles, keeping cool is the main concern. The reason is that you have all these sources of heat (sunlight, equipment, computers, etc) that can only be shed by radiating back into space.

Space actually does have temperature in the form of very small amounts of mass and background radiation. Because of the near-total lack of mass, it is generally quite cold - it just takes a very long time for things to radiate enough heat to cool off.

[Cashen]

I fail to get any benefit using hydrogen or nerva engines.

I ran into the same problem but there's a simple exlanation. We are used to measuring fuel on a volumetric basis, because the fuel tanks come in standard sizes with standard volumes. On a volumetric basis, hydrogen is a terrible fuel, because it is extremely low density. You cannot compare two engines using regular fuel and using hydrogen if they are fed by the same size tank. Hydrogen's advantage is purely in mass, because its extremely light, so you can get away with smaller engines pushing much bigger fuel tanks.

That being said, I'm still mostly concerned with volumetric efficiency because tanks come in standard sizes, so I've chosen not to use the advanced fuels part of this mod.

[AngelLestat]

I know that H2 is low density, for that reason I am using 2 orange tanks to rise 1 silly pod with help of 3 big solid booster!

But even that.. there is something very wrong here. The space shuttle use also H2 with O2, and the orange tanks is not 20 times more big than the shuttle!

Also the nerva engines had to be very efficient!! and they are not.

So if there is not a install problem, I have to said there is a big problem in the parameters. How much H2 can enter in the tanks or how much energy you get from them or I dont know..

[Starwaster]

Space actually does have temperature in the form of very small amounts of mass and background radiation. Because of the near-total lack of mass, it is generally quite cold - it just takes a very long time for things to radiate enough heat to cool off.

I stand by my statement, insofar as it has bearing on spacecraft parts and whether they stay cool by virtue of 'space is cold'. In point of fact its 'near-total lack of mass' is WHY it won't cool your spacecraft down. The denser a medium is the more effective it is at transferring heat to or away from anything you need heated up or cooled down. This is why you can put your hand into an oven set to 400 degrees Fahreneheit for short periods of time with no lasting effects but if you put your hand in water that has been heated to 212 degrees Fahreneheit (i.e. boiling) you will be suffering second degree burns.

[The Lone Wolfling]

So, some thoughts. Assuming a single stage throughout, and in vacuum. LF = Liquid Fuel, OX = Oxidizer, LOX = Liquid O2, H2 = Liquid H2

The mass ratio of LF/OX is ~46.32. The natural log of this is ~3.84.

The mass ratio of LF/LOX is ~14.73. The natural log of this is ~2.69.

The mass ratio of H2/LOX is ~8.940. The natural log of this is ~2.19.

Delta-v is E_vel*ln(M_f/M_i). In the limit, M_f/M_i is equal to the tank mass ratio. As such, the maximum delta-v attainable by a single stage is equal to ln(TMR) * Isp * G.

So, let's look at the LV-909 for a moment.

Its Isp with LF/OX is 370. 370*3.84*9.82 = 14000m/s.

Its Isp with LF/LOX is 390. 390*2.69*9.82 = 10300m/s.

Its Isp with H2/LOX is 460. 460*2.19*9.82 = 9890m/s.

So, for a single stage with the LV-909, always use liquid fuel / oxidizer. The mass ratio decrease more than kills the increase in specific impulse. Is this intended?

To quantify that for other engines, just divide the logs.

An engine has to have a specific impulse in LF/LOX mode of at least 1.42x of LF/OX mode to be worth it.

An engine has to have a specific impulse in H2/LOX mode of at least 1.75x of LF/OX mode to be worth it.

An engine has to have a specific impulse in H2/LOX mode of at least 1.23x of LF/LOX mode to be worth it.

Again, assuming a single stage. With multiple stages it might be worth it, I don't know though.

Next, let's look at how to extend this to multiple stages. Assuming that the decoupler weight is negligible, you can have an infinite number of decouplers and infinitely small fuel tanks, and as such carry no extra tank mass at any point. Effectively, you're also burning the dry mass of the fuel tanks with zero specific impulse. When you work out the fuel usage equation, this works out to an effective specific impulse of Isp / (1 + 1 / mass ratio). Math follows:

Isp_eff = sum(thrusts) / sum(mass flow rates)

Isp_eff = thrust / (thrust / Isp + 1 / (mass ratio) * thrust / Isp)

Isp_eff = 1 / (1 / Isp + (1 / (mass ratio)) / Isp)

Isp_eff = Isp / (1 + (1 / (mass ratio)))

Now, as to how to compare rockets.

Isp₁ / (1 + 1 / TMR₁) > Isp₂ / (1 + 1 / TMR₂)

Isp₁ / Isp₂ > (1 + 1 / TMR₂) / (1 + 1 / TMR₁)

As such, the following applies in multistage mode.

An engine has to have a specific impulse in LF/LOX mode of at least 1.05x of LF/OX mode to be worth it.

An engine has to have a specific impulse in H2/LOX mode of at least 1.09x of LF/OX mode to be worth it.

An engine has to have a specific impulse in H2/LOX mode of at least 1.04x of LF/LOX mode to be worth it.

So now lets compare the LV-909 and the LV-N.

The mass ratio of H2 is ~3.970. The natural log of this is ~1.38.

Its Isp is 850. 850*1.38*9.82 = 11500 m/s.

In other words, it is always more efficient with a single stage to use a LV-909 (in LF/OX mode, none the less!) than a LV-N. At 2.33 tons, a LV-909 has ~2670 m/s of delta-v while the LV-N has 0, and it never catches up.

...is this intended?

Edited August 11, 2013 by The Lone Wolfling

[AngelLestat]

UH you guys are still discussing about heat in space? Well I will help to clear this out so then someone can help me to know whatt is wrong with the nerva engines.

Is true that in a space station if you dont manage well the heat, it will become a problem.

How Starwaster said the heat source comes from: "(sunlight, equipment, computers, etc)" and human heat.

But also is not difficult get rid of excess heat in space.

if you have anti-radiation panels like those in space station, then the heat from the sun is not a big issue.

And in space, if you want to get rid of heat, you can do it in high effiency using heatsinks.

For that reason the space station only has some small heatsinks to solve all the issue. Becoz is more effiecient radiate with heatsink in space than here. Becoz in space (with no direct sunlight or earthlight) you had a background radiation about 3 kelvin.

You will understand better this if you see the Stefan-Boltzmann Law.

When you have: (heat emitted in watt) = material * bolltzman constant * Area * (Body1Temp^4 - Body2Temp^4)

Here in earth you will find that all bodys are almost at the same temperature, so the radiation that comes from other bodies is almost the same that comes out from yours.

So a common case of thermal dissipation in earth by radition it will be like this: (300k^4 - 280^4) (this is only a delta of 20 degrees), but in space it will be (300k^4 - 3k^4) and that is a big big number.

You will see the heatsinks in the space station, and almost all of them are to improve the solar cells efficiency. These are always in parallel with the sunlight radiation.

But back to the discucion, there is not a easy way to make a whole tank not be affected by radiation and keep a cryogenic temperature how we need. So the cost-benefic that you get is not so great.

PD: I just saw The Lone Wolfling post. I will check later if that has something to do with the nerva problem that I am seeing.

[Zander]

the way this mod is distributed is terrible. You have to go in and find a zip and extract it into the right place. i keep getting it wrong and the mod gets completely screwed up and I see like 2 of everything or stuff missing.

separate it into 2 versions a core and an advanced and just make it so the advanced version can be pasted into gamedata and it will already contain the file structure and overwrite or add the necessary files. There's no reason it needs to be so complicated. I dont consider myself that computer illiterate and I screwed up the installation multiple times.