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

[Cepheus]

This is really cool.

[SchroedingersHat]

so i had this before, and it worked fine love the mod, but now ive gone through and redid all the addons and mods i have and now it doesnt work, gets to the pods and fails to load the capsules IDK no crashes or anything so no log, just gets to them in the load screen and stops loading

using the entirety of KW and Novapunch, and mechjeb2 w/ latest dev build

anybody else have this issue?

I've often found mods packaged by people on macs break unless I delete the MacOSX folder (there is more than on such folder in this). Also check that you have one level of nesting for the realfuels folder, ie. ModularFuelTanks/RealFuels/some files not ModularFuelTanks/whateveryourzipprogrampicked/Realfuels/somefiles

[hellion13]

I've often found mods packaged by people on macs break unless I delete the MacOSX folder (there is more than on such folder in this). Also check that you have one level of nesting for the realfuels folder, ie. ModularFuelTanks/RealFuels/some files not ModularFuelTanks/whateveryourzipprogrampicked/Realfuels/somefiles

ok deleted all the mac folders, same issue tho, soon as i unzip the realfuels file into any directory i lose, gets to above spot on the load bar and hangs, if i dont unzip the real fuels file the game loads but i have no indication of whether the mod is on or not, no extra GUI same isp's as stock game nothing in the action groups idk what the deal is

quick question tho, was the NP compatibility fix for the 1.x NP, or Novapunch2? i scanned through earlier to see and i seen that NP, in general was but i didnt see what version lol

edit 1 going to redownload

edit 2 noticed something checking the .cfg files in both the unzipped realfuels file and the configs for the tanks, the Squad .cfg files have horrible formatting and are unreadable(opened in notepad word wrap tried on and off), but the other .cfg files for AIES, or KW tanks and fuels have good formatting and are easy to read which makes me wonder, for the game loads fine until it gets to the Squad parts which on the load bar for me is usually where the fastest load times occur before it jams

edit 3. i have no idea what i did but it works now, got options i the action groups for stock engines but nothing for nova punch

Edited July 16, 2013 by hellion13

[SchroedingersHat]

quick question tho, was the NP compatibility fix for the 1.x NP, or Novapunch2? i scanned through earlier to see and i seen that NP, in general was but i didnt see what version lol

edit 1 going to redownload

I've been running the latest novapunch with this just fine.

I did have issues in the past. One is that some other mods include modulemanager.dll. Do a search for it and ensure that you have exactly one copy and that it's the latest one

[hellion13]

OK its official i am a BLIND IDIOT LMAO, it wasnt that i had 2 copies of the mm.dll, cuz like said i got it to work, just to explain this to people who have this issue in the future, when you unzip this into KSP and want to use the advanced features( i cant believe it was something this simple giving me so much ****e) it would come up with a folder named realfuels along with the realfuels.zip, go in delete EVERY mac folder you can find (unless you are on a mac) then delete the realfuels FOLDER and THEN unzip the zip file.

i have no idea why this works NOW i did this before and still got the hang in the load screen but right now its working just fine

edit: also it helps if you have the extra .cfg files buried in the thread on page 20 something, for using NP and others that the stock mod doesnt come with.....

Edited July 17, 2013 by hellion13

[RuBisCO]

Ok think I got it to work, I can now fill my fuel tanks with any fuel I made up (ammonia). I think my problem was that I had saved the part I was testing and as such it would not update with all the changes I would make with the RealTankType.cfg and Resource.cfg files. So always start off by selecting a tank from the VAB menu rather then loading one you saved previously.

[ehlampley42]

I have tried looking through this post for the answer to my question but I couldn't find it. Sorry if I missed it. I am having problems activating the real fuels section of the mod. I have tried unzipping it, moving it, replacing the standard cfg with it files. No matter what I do KSP either will freeze part way though loading or it will not give the different fuel options. Can anybody tel me what I am doing wrong and how to properly install the real fuels?

Thanks

[hellion13]

I have tried looking through this post for the answer to my question but I couldn't find it. Sorry if I missed it. I am having problems activating the real fuels section of the mod. I have tried unzipping it, moving it, replacing the standard cfg with it files. No matter what I do KSP either will freeze part way though loading or it will not give the different fuel options. Can anybody tel me what I am doing wrong and how to properly install the real fuels?

Thanks

MAN i just went through this myself, delete whatever you have of the mod and redownload it fresh, unzip it somewhere other than ksp into its own file, go in to it should have the gamedata folder and a mac osx folder, delete the mac folder,and go into the gamedata folder. here is where i had issues and why i told you to delete the whole thing, should have the tanks folder and the source folder, go into the tanks folder. unzip the realfuels file, go in and delete the mac folder thats in it, now as far as stock KSP goes you should now be good, but if you want the same abilities for KW, novapunch and some others you need to go to page 21 of this thread post #204, and download the config files that are linked there the .cfg fils for tanks go in with the other tank cfg files and the fuels go in the real fuels folder that you unzipped, then go all the way back out until you are looking at the gamedata folder for the whole mod, copy(or cut) and paste it in to the KSP main folder( where the gamedata folder is along with everything else) dont try to one at a time the folders into the ksp folder for some reason this failed to work as well have to let the gamedata folder merge with the KSP gamedata folder.... this should fix your problem it is what fixed it for me

also when you go to change fuels, its in the action group part just click on the tank or engine and a window should pop up on the left over the action groups

Edited July 17, 2013 by hellion13

[ehlampley42]

Thanks you are a life saver. I have been fighting with thing for the last 2 days

[hellion13]

yeah this one was a pain to get working, there really needs to be a readme or install instructions, most mods just unzip into the game but this one took some doing, i hate to tell the mod creator how to make his mods but it would be somewhat easier to make the advanced and basic parts separate, all the mod is is some .cfg files and a .dll, 2 folders in the main zip file one for advanced and one for basic would be pretty simple, but i didn't make the mod and im not gonna worry about it, i put some pretty explicit instructions up earlier anybody else having issues can scan through and find them

[RuBisCO]

MAN i just went through this myself, delete whatever you have of the mod and redownload it fresh, unzip it somewhere other than ksp into its own file, go in to it should have the gamedata folder and a mac osx folder, delete the mac folder,and go into the gamedata folder. here is where i had issues and why i told you to delete the whole thing, should have the tanks folder and the source folder, go into the tanks folder. unzip the realfuels file, go in and delete the mac folder thats in it, now as far as stock KSP goes you should now be good, but if you want the same abilities for KW, novapunch and some others you need to go to page 21 of this thread post #204, and download the config files that are linked there the .cfg fils for tanks go in with the other tank cfg files and the fuels go in the real fuels folder that you unzipped, then go all the way back out until you are looking at the gamedata folder for the whole mod, copy(or cut) and paste it in to the KSP main folder( where the gamedata folder is along with everything else) dont try to one at a time the folders into the ksp folder for some reason this failed to work as well have to let the gamedata folder merge with the KSP gamedata folder.... this should fix your problem it is what fixed it for me

also when you go to change fuels, its in the action group part just click on the tank or engine and a window should pop up on the left over the action groups

Oh so that what that corrupting file was, its something for mac. Yeah the mod should have instructions stating "if you are not an apple chimp DO NOT UNZIP THIS PART!"

[illectro]

I took a look at this, seriously, the installation process needs fixed, but other than that.....

[hellion13]

LOL you know when the Manley has trouble there is something wrong

[Whirligig Girl]

May I suggest addition of Hypergolic Propelants?

[RuBisCO]

May I suggest addition of Hypergolic Propelants?

Why? how will it in the game provide noticable feature or advantage? We would need engines with limited number of times we can start them for hypergolics to have a notiable advantage (no ignition soruces, potentally unlimited start/stop cycles)

[princess venus]

what is this compatable with?

[hellion13]

what is this compatable with?

off the top of my head, KW, nova punch, spherical tanks, kspx, stock ksp, look through the mod there are .cfg files for the compatible add ons although there is a separate DL for some of the configs a few pages back in the thread

[cxg2827]

edit, re-read first post. I'm an idiot

Edited July 18, 2013 by cxg2827

[illectro]

Why? how will it in the game provide noticable feature or advantage? We would need engines with limited number of times we can start them for hypergolics to have a notiable advantage (no ignition soruces, potentally unlimited start/stop cycles)

Well that would be a whole 'modular engine' mod where you choose to cut down on engine mass and complexity by removing the plumbing for engine ignition. In career mode engines with hypergolic fuels would be cheaper to develop and have fewer parts to fail. One of the reasons why the stock NERVA has lousy thrust and ISP at sea level is because they lacked any other way to balance it, but if you have to deal with extra bulky LH2 fuel that evaporates that becomes a different path to balancing.

[Whirligig Girl]

Realism, for one. difference in Isp and thrust.

[CaptainArbitrary]

One of the reasons why the stock NERVA has lousy thrust and ISP at sea level is because they lacked any other way to balance it

Believe it or not, the stock NERVA's sea-level Isp is far higher than it should be.

I know you know this already, Scott, but for others: The reason rocket engines have different specific impulses at sea level and in vacuum is because of something called pressure thrust. Everybody knows this equation already: F = dm ve + (Pe – Pa) Ae. The thrust an engine develops is the sum of two components: the momentum thrust (mass flow times exhaust velocity) and the pressure thrust (difference between the exhaust pressure and the ambient pressure times the area of the nozzle exit). The first term is constant for a given throttle setting. But the second term varies depending on where you are. At sea level, the pressure term is generally going to be negative, because the exhaust is expanded to a lower pressure than ambient pressure. The result is less thrust at sea level, and a lower specific impulse.

I ran the numbers for the LV-N engine, as it's modeled in the game. It's got a nozzle exit diameter of 80 centimeters, and given its nature we can safely assume it's designed to work at altitudes above 30 kilometers. That makes the pressure thrust at sea level just a hair over –50 kilonewtons. And remember that in a vacuum the LV-N only develops 60 kilonewtons! That means it should develop less than 10 kilonewtons at 100% throttle on the launchpad, and have a sea-level specific impulse of only 123 seconds.

(For the geeks like me: If we assume the LV-N exhaust pressure is 0.0025 atm, indicating an operating altitude of 30 kilometers above Kerbin sea level, we get a pressure thrust in vacuum of 0.0025 atm times the area of the nozzle exit, or 0.126247 kN. So the momentum thrust is 60 kilonewtons minus that number, or 59.8738 kilonewtons. Solving F = dm Isp g₀ with that value for F and the vacuum Isp of 800 seconds, we get a mass flow rate through the engine of 7.63178 kilograms per second. At sea level, the total thrust is the momentum thrust plus the difference between ambient pressure and the exhaust pressure times the area of the nozzle exit. The pressure thrust term at sea level, then, is –50.8053 kilonewtons, making the total thrust at sea level 9.19475 kN. Solving F = dm Isp g₀ again with that F and the mass flow rate we calculated before gives us a sea-level Isp of 122.855 seconds.)

As for the thrust, though, you're absolutely right. The stock NERVA engine has a throat diameter of 20 centimeters (measured off the 3D model), which is fricking enormous. In order to have the exhaust flow reach the speed of sound at the nozzle throat, the mass flow rate out the nozzle needs to be a mind-boggling 639.075 kilograms per second (assuming NERVA-like chamber temperature and pressure of 2360°K and 30 atm). That comes out to a thrust of 5,598.1 kilonewtons … which is actually not unrealistic for a NERVA-type engine of those dimensions and specifications. It's just that that kind of thrust is completely bonkers for KSP. So the developers arbitrarily set the thrust very low for, as you said, reasons of gameplay.

(On a personal note, Scott, I have absolutely devoured your Reusable Space Program series, and eagerly await future installments. Thanks so much for making it.)

[hellion13]

Well that would be a whole 'modular engine' mod where you choose to cut down on engine mass and complexity by removing the plumbing for engine ignition. In career mode engines with hypergolic fuels would be cheaper to develop and have fewer parts to fail. One of the reasons why the stock NERVA has lousy thrust and ISP at sea level is because they lacked any other way to balance it, but if you have to deal with extra bulky LH2 fuel that evaporates that becomes a different path to balancing.

wonder how that would work? Would it restrict the normal engines to a limited number of restarts, unless you changed it over to use hypergolic fuels? and wouldn't changing it over reduce mass on an engine that no longer needs the "plumbing" for an ignition source?

i know the third stage in the Saturn V could be restarted and i think the LEMs decent stage as welll, im not sure though, along with the space shuttles main engines but i cant remember how many times for any of them and they are the only ones i can think of at the moment unless any of SpaceXs stuff can...

[maackey]

So I downloaded this just now, and have been playing around with the different fuel types. I made a test rocket (similar to the one in Manley's video) and switching only the fuel types MechJeb gave me these values:

LF/OX - 3401 dv - 1.14 twr - 4.5 tons

LF/LOX - 3246 dv - 1.28 twr - 4.4 tons

H2/LOX - 1764 dv - 1.5 twr - 2.7 tons

I haven't done very extensive testing, but first impressions -- I'm not sure why I would want to use anything but LF/OX combo. H2 gives better TWR (cause its light) but the dV is cut in half. It seems to me if I wanted a similar weight or twr I'd just take half the (LF/OX) fuel. What kind of fuel/engine/payload fractions do I need to make efficient use of the new fuel types, if that is even possible?

I'm going to have to drastically change my designs for nuclear rockets as well

[RuBisCO]

Well that would be a whole 'modular engine' mod where you choose to cut down on engine mass and complexity by removing the plumbing for engine ignition. In career mode engines with hypergolic fuels would be cheaper to develop and have fewer parts to fail. One of the reasons why the stock NERVA has lousy thrust and ISP at sea level is because they lacked any other way to balance it, but if you have to deal with extra bulky LH2 fuel that evaporates that becomes a different path to balancing.

Yeah but hypergolic fuels should be way more expensive. Hyperoglic fuels mean no ignition source and potentially unlimted engine restarts (with pressurized fuel), room temp storable (no boil off) but these fuels are IRL more expensive to make and handle then LOX, LH2 and RP1.

Nuclear engines should have less thrust, lower T/W ratio, I think the best projected was with Project Timberwind and that was a T/W of 30, compared to LOX/LH2 engines doing up to 80 and LOX/RP1 as high as 130! Nerva was a horrible ~4! But use having nuclear engines operate on "Oxidizer" and "Fuel" is stupid hence why I love RealFuels.

I think engines with limited throttling, limited number of starts and ullage motor requirements would be nice addition of realistic difficulty. Imagine starting an engine in orbit but not having done anything to deal with ullage and having the engine sputter and explode, would add another use for RCS (RCS tanks IRL are usually bladdered or pistoned so they can operate without worring about ullage). Ullage would also make fuel transfer tricky unless you spin the ships, have bladder or pistoned fuel tanks, or special intake traps like magnets for LOX or sticky sponge for LH2 (all these add weight).

maackey,

LH2 needs HUGE fuel tanks, LH2 has the same density as cotton candy! While "fuel" like keresene is nearly as dense as water.

Edited July 19, 2013 by RuBisCO

[hellion13]

I think engines with limited throttling, limited number of starts and ullage motor requirements would be nice addition of realistic difficulty. Imagine starting an engine in orbit but not having done anything to deal with ullage and having the engine sputter and explode, would add another use for RCS (RCS tanks IRL are usually bladdered or pistoned so they can operate without worring about ullage). Ullage would also make fuel transfer tricky unless you spin the ships, have bladder or pistoned fuel tanks, or special intake traps like magnets for LOX or sticky sponge for LH2 (all these add weight).

it WOULD be nice for someone to do this as a separate mod or as a hard mode(the possibilities!), but i think it would break the baseline kerbal experience. this modular tanks/fuels mod is nice to play around with, even gets some of my heavier constructs in to orbit with a little more deltaV in the final stage but doesn't go as far as making it a hardline sim. but it does introduce the idea of different fuels for different situations, like having the fuel have a little more"octane" for lifting in the first and second stages and maybe a fuel that can go a bit longer in the later stages... as for a limited number of restarts? you gotta make orbit first, after that you are halfway to anywhere....