[1.8+] Real Fuels

[NathanKell]

Scripto: IspV and SL work like this: first, you look up engnie type and tech level in the list of atmosphereCurves. Then you multiply the sea level Isp found there by IspSL, and the vacuum one by IspV. You can find the techlevels stats in RealSettings.cfg or on the Isps sheet of my Calcs spreadsheet (link in second post of this thread).

Regarding mass: your problem is having an origMass in the ModuleEngineConfigs entry. If you speciy origMass, then part mass will be always set to origMass * techLevelMult (which is complex, but is roughly equivalent to original_vacuum_isp / current_vacuum_isp). Take origMass out and leave basemass = -1 and then neither ModularTanks nor ModularEngines will mess with mass.

AbeS: add :Final to each of those @PART[]s. Also, heatProduction is a ModuleEngines value. Put it inside the @MODULE[ModuleEngines] block, say right next to maxThrust.

Eadrom: nifty!

[AbeS]

All right, I left it just as SFJackBauer made them, will change it and see if it works!

EDIT: It works now, thanks Nathan!

Edited January 9, 2014 by AbeS

[Scripto23]

Nathan thanks for explaining that. Also I completely forgot about the origMass value *facepalm*, that fixed it. I just need to adapt the other engines into the proper tech levels. I've uploaded the corrected version now

https://www.dropbox.com/sh/8mq09bh64veanv1/VA7GTqggOf

Silpion: Thanks for testing and I believe I have now corrected what you mentioned. As for the instability, I'm not sure if the trunk is the cause. My CoL indicator is far above my CoM indicator and I have never launched a stable rocket where this was the case. I think there is some drag value or something that needs to be changed along with the rescale. For instance, when I take off all the bits such as ladder, parachute, interstage, fairing covers, superdracos, etc then my CoL will be below CoM. The only explanation I have is that these small parts are providing more lift or drag than they should, and being near the top of the rocket it pulls the CoL toward it.

Below I've posted 3 pics,

1 is with no changes (unstable)

2 is with fins (stable)

3 is with the bits removed and no fins (stable)

[Guest]

Try adding a size-2 node under the 1st stage engines. Nothing will be attached to it, but this will allow FAR to properly calculate drag.

[Silpion]

Using new cfg.

So yeah, they rockets are still unstable, but not so unstable that you can't get it to launch if you just keep on top of it. However the floppiness issue is severe, particularly for the Heavy with a full load. I managed to coax a 50 ton payload into orbit with my heavy, but it was a wobbly ride. Had to fly with SAS off to prevent a resonance, but even then it was a challenge.

Is there some kind of rigidity factor that has to be scaled up as well? I don't know how this stuff works. I'm using the reinforcement mod btw.

Also I note that when I make a craft which is just a fuel tank, the CoL marker is near the top, while CoM is at the center. Weird.

Some other issues:

Strangely, in the FH you provide, the center 1st stage tank has less fuel volume than the side tanks. I can't seem to get them to fill equally. My own FH I built from scratch fills up fine. Maybe this is intended to be some kind of virtual fuel usage from the 3 engines not cross-fed?

Concerning landing legs: this might not be your doing, but if you want to distribute this, I don't think the upper stage should have those giant legs. From what I've seen from SpaceX, the 2nd stage legs are going to be little peg guys that fit inside the interstage. Also in your FH, the side boosters are each missing a leg.

Edited January 9, 2014 by Silpion

[Guest]

Are you using KJR? Anyway, I'm gonna try those configs when I have the time and see what's going on.

[Scripto23]

Dragon01, thanks I'll try that.

Silpion, I think the wobbliness and CoL issue are both from the node problem that Dragon01 mentioned. I'm going to figure out how to change that and see if it fixes things.

For the tank filling thing, I think that specific tank is from an old save before I updated the volume and then I only changed the side tanks and forgot about the middle one, I'll fix that (and the missing legs) and update the craft. With MFS when you update a volume in the config you have to reselect the part from the menu, parts that are already integrated into saves won't change, so that's where that error came from.

For landing legs, yeah that's the way Laz had it, but I agree it doesn't look quite right. I'll see what I can come up with.

[ferram4]

If the Falcon 9 has been re-sized to be the appropriate ~3.7m across, intended for a RSS setup, you should make sure that the bottom node is set to be a size 4 node.

I think that the instability is large caused by the landing legs on the second stage; there is a possibility that something strange is happening with the solar panel covers or the superdracos, but without know how those parts are set up I can't tell.

FAR v0.12.5.2, correct?

[Scripto23]

ferram, I was on v0.12.5.1. Just upgraded, thanks. I put node size 4 on the appropriate sections of all of the 3.7m parts and I believe that fixed the wobbly issue, but the flight stability issue. I just disabled my rescale config and looked at how the "stock" Laztek SpaceX rocket is supposed to look and surprise surprise the CoL is in the same place . So next I tried disabling FAR and the rocket was flying stable. Below are pics of the stock rocket CoL with and FAR and without. Not sure what to do now.

Edited January 9, 2014 by Scripto23

[xZise]

Man, you did the right thing with actual data, but for once the first line tells the problem. XD

You have to delete the file in the realfuels folder that has the Squad NTR engine in it. If you don't, there's two files trying to change it and it hangs there.

Ah this did it (and at least I now know where the logs are). After I posted it I first only removed your NTR additions (as I haven't developed it yet I don't use it anyway) which worked fine.

Fabian

[J_Davis]

Fabian: Yeah, doing that will work too. You just have to make sure they aren't listed with two sets of config.

[Silpion]

Scripto: Mind sharing your version with the better nodes? I tried strutting up my falcon heavy and when it's stiffer it is much easier to fly even with its instability.

Also, I think the upper stage tank has the volume for the Falcon 9v1.0. I believe that the 1.1 has a much larger upper stage tank, given the higher thrust and burn times listed on the wiki page. I calculate that the volume should be 87000 rather than 45000. The tank models look about right for that volume relative to the lower stage. That mass up front would also help the stability a little.

Edited January 10, 2014 by Silpion

[ferram4]

Get rid of the landing legs on the upper stage. Seriously, those are going to make the thing less stable and are probably part of the issue.

[Silpion]

I already do on my versions, but they're still unstable. And this is with a heavy fairing-enclosed payload rather than the potentially awkward Dragon.

[Scripto23]

Silpion, sorry I forgot to upload the most recent build (it's done now). But after further flights I realize I'm still getting the wobbliness between that gold colored falcon flight control system and the interstage above it. However if this piece is removed then no more wobbles. Something is wrong with the attachment function of that part, I'll have to look into it. You know what, you're right about that tank volume. So many more things make sense now.

ferram, I got rid of the landing legs but it didn't really change anything. The Falcon Heavy is ever so slightly more stable, but both rockets want nothing more than to fly backwards.

Edit: Alright forget that last part. It appears that with the right amount of fuel providing additional mass in the upperstage (thanks Silpion), plus not having that one wobbly part, the rocket is much more stable. I've also uploaded an updated craft for that.

Edited January 10, 2014 by Scripto23

[ferram4]

Oh, that gold part between the Merlin 1D vac and the second stage is a separate part? That would cause the issue; make sure that there are struts from the second stage to the first stage (or to the interstage fairing) to stiffen that up then.

It might also be part of the stability issue; make sure that the interstage fairing actually has the word "fairing" in the title so that FAR picks up that it should shield the parts inside it from aerodynamic forces.

[Scripto23]

Yeah that part is really thin. Even with 4 struts connecting it to the top piece and 4 connecting it to the bottom, it still wobbles. That alone will cause the rocket to be unstable. If I replace it with a similar part (only difference is it has a heatshield and is a .1 thicker) then there's no wobble.

[tonnyrat]

Does anyone have a stockalike config that works with NovaPunch? Everytime I try to load this mod and NovaPunch together it hangs on the load screen.

It does this with at least 3 engines since I have tried removing different parts.

PartLoader: Compiling Part 'NovaPunch2/Parts/AuxAndRadialEngines/NP_AuxMotors_1_25m_RetroPack/part/NP_aux_125m_retropack'

(Filename: C:/BuildAgent/work/ea95e74f6e5f192d/Runtime/ExportGenerated/StandalonePlayer/UnityEngineDebug.cpp Line: 54)

Added sound_rocket_hard to FXGroup running

(Filename: C:/BuildAgent/work/ea95e74f6e5f192d/Runtime/ExportGenerated/StandalonePlayer/UnityEngineDebug.cpp Line: 54)

Added sound_vent_soft to FXGroup deactivate

(Filename: C:/BuildAgent/work/ea95e74f6e5f192d/Runtime/ExportGenerated/StandalonePlayer/UnityEngineDebug.cpp Line: 54)

SolidFuel not found in resource database. Propellant Setup has failed.

(Filename: C:/BuildAgent/work/ea95e74f6e5f192d/Runtime/ExportGenerated/StandalonePlayer/UnityEngineDebug.cpp Line: 54)

NullReferenceException: Object reference not set to an instance of an object

at ModuleEngines.SetupPropellant () [0x00000] in <filename unknown>:0

at ModuleEngines.OnLoad (.ConfigNode node) [0x00000] in <filename unknown>:0

at PartModule.Load (.ConfigNode node) [0x00000] in <filename unknown>:0

at Part.AddModule (.ConfigNode node) [0x00000] in <filename unknown>:0

at PartLoader.ParsePart (.UrlConfig urlConfig, .ConfigNode node) [0x00000] in <filename unknown>:0

at PartLoader+.MoveNext () [0x00000] in <filename unknown>:0

(Filename: Line: -1)

RemoteTech: ModuleSPU: OnDestroy

(Filename: C:/BuildAgent/work/ea95e74f6e5f192d/Runtime/ExportGenerated/StandalonePlayer/UnityEngineDebug.cpp Line: 54)

[Agathorn]

I find this a bit confusing. If I have multiple engine stages using the same fuel types, but different mixes, then I see this when fueling a tank:

As you can see, in the bottom left, it shows me the two engines use the same fuels but slightly different mixes. The problem is I don't know which is which, or which one to use.

[Silpion]

Agathorn: Yeah I've run into that multi-fuel-mix problem too. I just pick one, see the delta-V in engineer/mechjeb, then try the other, and keep the one that's higher.

Scorpio: The SpaceX stuff is flying pretty good, so I've moved to PM's for bug reports.

[ferram4]

Hovering over the button creates a tooltip that lists the engines that use that mix. It's actually cool, it gives you an idea of what engines you can mix-and-match and not end up with leftover fuel.

[Agathorn]

Hovering over the button creates a tooltip that lists the engines that use that mix. It's actually cool, it gives you an idea of what engines you can mix-and-match and not end up with leftover fuel.

Doh! I never noticed that until now. Guess now I just need to get better at knowing the names of my engines.

[NathanKell]

EDIT: tooltips ninja'd by ferram.

tonnyrat: the Stockalikes config in the second post does, as does RftSEngines (link in second post). Neither as yet support the AuxMotors though.

[ShaneCluning]

Hi NathanKell,

I'm having a weird issue and hopefully it's just me being a bit stupid but I've set up my KSP to be Realism Overhaul but when I'm using Real Fuels I can access the fuel tank allocation GUI but I cannot scroll it at all. nothing I do will make the GUI scroll down so I can't access the auto fill options and even some of the real fuel tanks. I use 1680x1050 res as I like it windowed so I can't see everything. Any ideas?

[NathanKell]

You should see a black embossed capsule-shaped bar to the right of the fuel list. It should start near the top and go most of the way down. Grab it and drag it down. That will scroll down.