Raptor831

Stockalike RF Engine Configs v3.2.6 [01/20/19][RF v12]

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10 hours ago, Raptor831 said:

No specific plans, but I didn't realize they were out of date. If you can update them, submit a PR and I can merge them in to the main thing. Also, you can use http://bit.ly/rfstockalike to help generate all the configs (if you hadn't seen that before).

I got the STME (SSME) and STBE (STS Block 2 LRB engine), as well as all the smaller engines working, but I need to get the External Tank and the lifting body fuselage segments working. I wrote an RF config before for BDB tanks, but I can't remember the multiplication factor you used for the Stock Fuel to RF conversion.

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4 hours ago, DJ Reonic said:

I got the STME (SSME) and STBE (STS Block 2 LRB engine), as well as all the smaller engines working, but I need to get the External Tank and the lifting body fuselage segments working. I wrote an RF config before for BDB tanks, but I can't remember the multiplication factor you used for the Stock Fuel to RF conversion.

The factor is 5. Stock fuel "units" are around 5 liters in reality. If you get technical, I think it's like just over 5 if you measure tank sizes and do the volume calcs yourself. Also, I'm pretty sure there's a catch-all in RFStockalike that'll do the tanks for you. But if you need specific configs you can do that, the catch-all doesn't run on ones that already have MFT modules.

As for the lifting features, I have no stinkin' idea how to make that work. :P

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26 minutes ago, Raptor831 said:

The factor is 5. Stock fuel "units" are around 5 liters in reality. If you get technical, I think it's like just over 5 if you measure tank sizes and do the volume calcs yourself. Also, I'm pretty sure there's a catch-all in RFStockalike that'll do the tanks for you. But if you need specific configs you can do that, the catch-all doesn't run on ones that already have MFT modules.

As for the lifting features, I have no stinkin' idea how to make that work. :P

The lifting bodies have RCS tanks in them. "A" is for STS based craft,and "B" is for Buran based craft. They all have fuel switching as well as the External Tank, so in this case, that function would need to be overwritten via mm patch.

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@DJ Reonic Yeah, any fuel switching mods need to be removed from a part if RF is there. They just plain break everything. You can remove the modules from each part like:

!MODULE[B9PartSwitcher],* {}

I forget if that's the exact module or not, but it's just easier to nuke the switchers and allow MFT to work by itself.

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New and updated configs for beta-testing and bug squashing:

  1.  Updated Probes Plus (beta 0.16 version) parts configs (WARNING! Will conflict with old Stockalike_ProbesPlus.cfg) and engines plumes 
  2. Parts configs for Corvus CF mod.

Current problems:

  • Torekka Propulsion Module (Probes Plus) uses two ModuleRCS in part config. As a result there is no possibility  to change propellant or tech level for RCS.
  • Corvus fuel cell config is an unbalanced stopgap (I just steal numbers from Realism Overhal and Gemini Familiarization Manual).
  • Torekka and Landvermesser SRBs, perhaps, also require rebalancing (2911 m/s is too much for Surveyor-style Mun landing in 6.4x Kerbin system).

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Is it just me, or there is a problem with Nuclear engines?? With this mod they are ABSOLUTELY inefficient. Yes, there is ISP over 900, but they give as much deltaV as Poodle for the same mass of fuel, and much less for the same volume of fuel. For example poodle vave 220 thrust vac and eat 60 liters of fuel per second, LV-N trimodal eats 173 liters of Hydrogen per sec and only outputs 111 thrust. LV-N Nerv eats 101 liter and outputs only 60 trust. Can someone give me RIGHT ammount of fuel consumption for nuclear engines so I could use them again? Thank you!

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On 3/10/2018 at 6:52 PM, Battou said:

Is it just me, or there is a problem with Nuclear engines?? With this mod they are ABSOLUTELY inefficient. Yes, there is ISP over 900, but they give as much deltaV as Poodle for the same mass of fuel, and much less for the same volume of fuel. For example poodle vave 220 thrust vac and eat 60 liters of fuel per second, LV-N trimodal eats 173 liters of Hydrogen per sec and only outputs 111 thrust. LV-N Nerv eats 101 liter and outputs only 60 trust. Can someone give me RIGHT ammount of fuel consumption for nuclear engines so I could use them again? Thank you!

Nuclear engines tend to use hydrogen, which will make your rockets stupidly huge when you're used to KSP-style rockets. I think you're confusing liters (volume) to kg (mass). 100 liters of LH is going to mass *way* less than 100 liters of RP-1 or methane. Isp calculations use mass, so when you're using light fuels it's gonna make your Isp go way up but also your volume.

Try switching to methane for your NTRs, as that gives you a much better energy density. Otherwise, just build a bigger tank. Tanks are cheap and light, relatively speaking, so you can get away with it generally.

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10 hours ago, Raptor831 said:

Nuclear engines tend to use hydrogen, which will make your rockets stupidly huge when you're used to KSP-style rockets. I think you're confusing liters (volume) to kg (mass). 100 liters of LH is going to mass *way* less than 100 liters of RP-1 or methane. Isp calculations use mass, so when you're using light fuels it's gonna make your Isp go way up but also your volume.

Try switching to methane for your NTRs, as that gives you a much better energy density. Otherwise, just build a bigger tank. Tanks are cheap and light, relatively speaking, so you can get away with it generally.

Problem not in tank, problem is than nucklears give same deltaV for same mass. Try building poodle rocket of about 5000 deltaV and then lv-n trimodal rocket with 5000 deltaV and compare their mass. 

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2 hours ago, Battou said:

Problem not in tank, problem is than nucklears give same deltaV for same mass. Try building poodle rocket of about 5000 deltaV and then lv-n trimodal rocket with 5000 deltaV and compare their mass. 

That doesn't make a lot of sense, what are you saying has the same mass? The each total vehicle? The spent propellant? Neither case is possible at all; they can't have the same mass. In any event maybe you're just not using the NTR in the right kind of vehicle. It's the sort of thing that you would use on a vehicle that has a lot of mass to begin with and you want to lighten the load with a tank which is mainly hydrogen.

That said though,

@Raptor831  you might want to take a look at this line here: The engine mass in ModuleHybridEngine overrides the part mass and has the effect of slightly more than doubling the mass.

https://github.com/Raptor831/RFStockalike/blob/9aa89103a400370b6c2f04f74342eb021cfaa42a/GameData/RealFuels-Stockalike/Squad_NTR_modularEngines.cfg#L150

 

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@Starwaster Ah, thanks. I'll double-check what the mass is supposed to be there.

@Battou I'm also a little confused as to what you mean. If I make 2 stages with 5000 dV each, one using the NERVA and one using the Poodle, the NERVA one should end up being less mass overall since the fuel is so light. I haven't tested that in-game yet specifically, but if you have screenshots with a MechJeb or Engineer window up to show mass and dV that would be helpful. At least then I can look at something concrete.

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15 minutes ago, Raptor831 said:

@Starwaster Ah, thanks. I'll double-check what the mass is supposed to be there.

@Battou I'm also a little confused as to what you mean. If I make 2 stages with 5000 dV each, one using the NERVA and one using the Poodle, the NERVA one should end up being less mass overall since the fuel is so light. I haven't tested that in-game yet specifically, but if you have screenshots with a MechJeb or Engineer window up to show mass and dV that would be helpful. At least then I can look at something concrete.

Here are screens.

LV-N Trimodal 111Kn Thrust on Liquid Hydrogen, 4.6000 deltaV, 23 tonns

Poodle 200Kn thrust on Aerozine NTO, 4.700 deltaV, 24 tonns

 

mZ64KN2.jpg5mlQlUY.jpg

In Stock game nuclear engine eats same amount of liquid fuel, but without oxidyzer. I think you must reduce by half fuel consumption per sec, or tank mass will kill any benefit.

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@Battou

As I thought this is a perceptual problem on your part and not a problem with the engine part.

First: Do not compare any of the Real Fuels nuclear engines to the stock nuclear engine. STOP that. The stock nuclear engine is poorly designed and not based in reality. LiquidFuel an extremely dense compact fuel (probably some form of hydrazine) and the specific impulse (Isp) is way too high. Dense propellants will tend to have exhaust with high molecular mass and therefore lower Isp. To get higher Isp you need low molecular mass such as with hydrogen.  TL;DR the stock LVN is extremely overpowered and has performance that far outstrips the engine it is meant to model.

Second: Pretty sure It's been said to you repeatedly (@Raptor831 and I) liquid hydrogen nuclear engines require  a lot of tankage. THIS IS NOT A BUG.  The extra tankage requires extra mass.

Third: Because of point #2 you should NOT be using this kind of engine on a small ship like the one you are using. You need to learn when and when not to use  it. You've got some little Apollo type craft there, stick with the poodle or some other small light hypergolic engine. You use something like a nuclear engine when the mass of the hydrogen + hydrogen tankage is actually going to be lower than the mass of the fuel required by a smaller engine. In other words, an engine like that is best used for a larger payload where the propellant mass required for the poodle lowers your TWR too much. Then you might think about using a nuclear engine with all or mostly hydrogen tankage. 

Fourth: Get a mod that lets you replace all those tiny little tanks with one large tank. Sized properly you can see some mass savings.

An example of how they planned to use nuclear engines in the real world is for the Saturn V third stage (S-IVB). they planned to replace the single J2 engine with a NERVA and no LOX tankage.  The resulting stage would have been called the S-N. The goal was to increase carried payload as much as (or more than) to increase delta-V

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@Battou The problem is volume. You need lots more volume to get the same amount of mass for LH2. Which is why the Space Shuttle External Tank is so darn huge. If you pull the file @Starwaster mentioned before from GitHub now, you'll see I've commented out the mass line and it should give you a bit more dV than previously, since the mass was a bit too high. NTRs are basically a floating nuclear reactor, so they're gonna be a bit heavy compared to traditional chemical engines. But if you're only going for straight LH2 and not using the LOX afterburner, don't use the trimodal at all. Use the LV-N (i.e. NERVA in the real world).

You really need to check out Procedural Parts or some other large tank mod (i.e. Cryogenic Tanks, SpaceY, etc) to get enough tankage to make LH2 worth the volume. 2.5 meter rockets are not enough to make it worth it. I'd argue you need minimum 3.75-5m diameter before you feel a difference. For example, check out this Wikipedia link: https://en.wikipedia.org/wiki/Nuclear_thermal_rocket#/media/File:Orion_docked_to_Mars_Transfer_Vehicle.jpg

That's the Orion on the front of the craft. Generally in KSP stock-size, Orion is rendered as 3.75m diameter. Those tanks (and the inflatable hab) have to be at least double that, so we're talking 6.25m at the least in KSP-size. I think that's around 10m in real life, if my estimations are correct. And this craft is using 3 NTRs.

Basically, don't use NTRs unless you have something big and can afford the mass penalty.

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@Raptor831 Instead of commenting the line out, I suggest setting it to be the same as the part's assigned mass. That will allow mass improvements from tech level advances. Commenting the line out prevents that.

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15 hours ago, Starwaster said:

@Raptor831 Instead of commenting the line out, I suggest setting it to be the same as the part's assigned mass. That will allow mass improvements from tech level advances. Commenting the line out prevents that.

Bah! I was assuming it took it from the mass by default. Thanks again for the notice.

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2 hours ago, Raptor831 said:

Bah! I was assuming it took it from the mass by default. Thanks again for the notice.

The code only ever does anything meaningful when origMass > 0 - which is odd considering I've seen several examples of other configs (RO) where origMass = -1 and that has no effect whatsoever. (basically it gets ignored if it's not a positive value)

I'll probably create an issue over it so we can discuss it and decide if it should do anything else.

I've also been going over the rest of the NTR trimodal config and noticed it has both ModuleHybridEngine (an RF class) and MultiModeEngine (Squad's class) and they both do essentially the same thing; let you switch between two engine modes. I'm not sure which is the better choice.... Either one will work though MHE probably hasn't had any attention given to it it awhile. On the other hand, when I removed it from the config on my installation, the effects vanished and I haven't had a chance to look into why. 

 

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On 4/2/2018 at 2:24 AM, Battou said:

Any hope of getting this great mod updated for 1.4?

As always, that's tied to Real Fuels. The configs will work with RF as long as RF works. RF is 1.3 compatible per the forum thread at the moment.

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They haven't updated the Real Fuels thread yet but RF 12.7.0 is up as latest version on their Github as of two days ago.

Being an optimist I tried it with the current RF stockalike config and something is borked, most of the engines are MIA. But that was expected - there were posts on the RF thread reporting the same issue. Also mentions of lots of parts throwing nullrefs, method exceptions and the like.

I certainly wouldn't expect to see an update this mod until Raptor has a stable release of RF to work with.

Edited by EatVacuum
Grammar

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So apparently this broke in the latest version... If anyone could, please post up logs and ModuleManager.ConfigCache files for me. And also what parts are borked specifically (i.e. which mods, types of engines, etc). Honestly, it doesn't seem RF would have broken my configs, especially en masse like that, so I got nothin'. I'll try and test on a minimal install to see what's up.

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1 hour ago, Raptor831 said:

So apparently this broke in the latest version... If anyone could, please post up logs and ModuleManager.ConfigCache files for me. And also what parts are borked specifically (i.e. which mods, types of engines, etc). Honestly, it doesn't seem RF would have broken my configs, especially en masse like that, so I got nothin'. I'll try and test on a minimal install to see what's up.

What's broken?  I used this to test RF v12.7.1 - I only tested a few engines but they seemed to work fine.  There was a bug in RF v12.7.0 that broke nearly everything but that's fixed.

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3 minutes ago, blowfish said:

What's broken?  I used this to test RF v12.7.1 - I only tested a few engines but they seemed to work fine.  There was a bug in RF v12.7.0 that broke nearly everything but that's fixed.

I judged from the chatter here and on the RF thread. Apparently I should just test this stuff myself before assuming anything. :facepalm: :D

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20 hours ago, Iso-Polaris said:

Those stock reskinned stock engines are no longer supported by RF

Is there a planned update soon?

It's always been that way.  The question is of this mod being marked as compatible with KSP 1.6

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18 hours ago, blowfish said:

It's always been that way.  The question is of this mod being marked as compatible with KSP 1.6 

I understand this is only a stock config for RF mod, but it seems a little bit... outdated.

From where I can see, I can no longer select fuel types for LV-909 and Poodle .

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