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


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There's no config for the Terrier. Is there any post I can look at for the logic/conventions of how to write configs for the fuel tanks (whether it's always X units of LF/O converts to Y liters of capacity or if non-linear functions are used, etc)? It can't be too hard for me to write a config.

EDIT: Also, was the PB-ION intended to have 148 E/s electrical consumption? That's kind of 8.2 Gigantor XLs' worth of electrical consumption, and I'm wondering if it got changed to RF/RO's electricity units, and not changed back in this config.

I'll check for the Terrier. Don't have MRS installed on my game generally, so if I missed a liquid engine that's probably why. Another note, I don't mess with the ion engines, arcjets, or resistojets in any config generally. I don't have any good calculations on those and the spreadsheet isn't set up to handle those. I might be able to take a stab at those kinds of engines and figure out something to do with them, but no promises there. If anyone has some good data on those, feel free to link it here.

Formula for tanks is (LF + O) * 5. So, for a tank that has 600 LF and 400 O, you'd end up with a volume of 5000 liters. I count Monoprop as 1 unit usually, but EC is so small (in "volume") I generally don't count it. Format is thus:


@PART[part_name]:NEEDS[RealFuels]
{
MODULE
{
name = ModuleFuelTanks
volume = 5000 // (LF+O+MP)*5
type = Default // ServiceModule for any SM tanks, check the RF thread for more types
}
}

Raptor,

I think you should remove the B9 Jet Engines cfg's from your zip. They conflict with AJE. It looks like RealFuels got rid of them in their last release or two.

Problem with that is if I remove that and AJE is not installed, the jets don't work with RF at all. Reason they're here is because they got removed from RF proper anyway, and Nathan suggested I include them here instead. :wink:

Either way, I can add a condition to the MM config to not run if AJE is installed. That should at least solve the problem there.

As an update, I've went through my install and fixed up any engines I missed in SXT, NP2, and RLA. Added the R&S Capsuledyne Quadoodle engine as well. Download in the OP from the repo.

EDIT: Updated again, to add the B9/AJE fix

Edited by Raptor831
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Ah, well! That would explain it. The MRS version I downloaded was a few versions behind. Dunno how I got that version, but I checked the newest version and added the quad and the Terrier to the configs. Repo is updated but I didn't make a "release" yet. For those interested, just download the repo from GitHub.

@Starman4308 After reading your posts in the RF thread, I thought about a quick way to bring the ions back in line. You could write a config that scales the amount of xenon used back by the same factor that xenon got changed. That would at least bring them close to stock-ish balance. At least a good place to start.

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@Starman4308 After reading your posts in the RF thread, I thought about a quick way to bring the ions back in line. You could write a config that scales the amount of xenon used back by the same factor that xenon got changed. That would at least bring them close to stock-ish balance. At least a good place to start.

I'm pretty sure Near Future Propulsion has a bunch of configs for ions, so I can look there to see how to tweak electricity usage. I don't know if you want me to tweak the ions past "get them back to stock-ish", which should require only tweaking thrust/fuel flow and electricity/xenon ratio. If it were my own config, I'd probably take a crowbar to the thing, reduce Isp to 1800s, decrease thrust a bit (probably to 1 or 1.5 kN), and set the electricity usage to ~3-4 Gigantors' worth.

I know Nathan pointed out that, for 2 kN, it really should require 12,000 Gigantors, but I think most reasonable people will agree that we shouldn't be forcing players to use 12,000 Gigantors. In the meantime, I'll try and find if there are any part packs with larger RTGs, because if you do want to go through the route of increasing electricity consumption, you'd need a forest of stock RTGs to keep up.

EDIT: By the way: much thanks for the patience and help. First time writing any mod, even if it's just a config file.

Edited by Starman4308
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I'm pretty sure Near Future Propulsion has a bunch of configs for ions, so I can look there to see how to tweak electricity usage. ..snip..

EDIT: By the way: much thanks for the patience and help. First time writing any mod, even if it's just a config file.

Probably a good place to start. Also, I think NK's idea for scaling would be better, if you go there.

As for how far to go, write up what you would want to play. :) That's how I started this thing, so go for it. Reducing the ISP sounds reasonable to me, and adjusting as needed. The only metric I try to keep the same for the other engines is the thrust. If you can scale to that with reasonable success, go for it. If you need to, nerf the thrust a bit, just because the ions *are* overpowered. ISP I'd try to be accurate on, and electricity usage you can try to be realistic * scaling factor. We obviously don't want 12,000 gigantors, but maybe 12 isn't unreasonable for 2 kN?

There are also other mod solar panels (I'm thinking NFT-Solar, KOSMOS) that have much higher electricity production. I'd imagine being able to use fewer of those to get the most out of the electrics. NFP and/or KSPI might have a better handle on the balance though. And a big RTG ends up being a fission pile, right? Sounds quite kerbal to me. :wink:

And you're welcome. Honestly, I appreciate the help. More sets of eyes always catch more bugs.

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Well, I'll pick it up tomorrow/whenever I have time. I'm pretty sure I have the right way to rescale electricity consumption: take the electricity consumption per kilogram (180 E/kg for stock), multiply by the density of xenon gas, and then multiply by whatever scaling factor you want: that ratio should be 0.00106092 for a stock rescale. I also remembered to tweak mass to ~1/3 stock, roughly in line with the other engines. To the best of my understanding, the absolute ratios can be arbitrary, but the relative ratios determine how much gets spent (for example, you could have 50 LF + 50 O, or 0.5 LF + 0.5 O, and they would be the same).

Problem is I need to figure out how to properly write the config file so it modifies an existing propellant instead of adding one; I had the amusing sight of adding a 50% Xenon/50% Xenon mix to the fuel tanks when I tested this.

@MODULE[ModuleEngines]    {
@atmosphereCurve
{
@key,0 = 0 4200
@key,1 = 1 200
}
PROPELLANT
{
name = ElectricCharge
ratio = 0.00106092 // Calculated as such: stock PB-ION consumes 180 E/kg xenon, mutliplied by density of RF xenon.
}
PROPELLANT
{
name = XenonGas
ratio = 0.1 // Just realized I might want to set this to 1.0, because the above electricity ratio is E/unit, not E/0.1 unit like stock.
}
}

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You should be able to add names to the PROPELLANT nodes just like an @MODULE[name] call. So:


@MODULE[ModuleEngines]
{
...
@PROPELLANT[XenonGas]
{
@ratio = 0.5
}
...
}

That should just grab the node. You can also use the %NODE[name] syntax to modify the node if it's there but create the node if it is not. Useful if you don't know if your node is there yet.

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What would be the best way to send in bugfixes?I imagine a pull request would be the ideal way to go about it though. I'll look into getting github setup for myself (I think I may have already). Some of the tantares configs need a little tweaking, but I haven't a list of what the issues might be yet.

Not to be a questioning pest, but what is the best way to handle a tank/engine combo? Where the engine is a part of the tank, I mean. That comes up in several places in that modpack. I think I see how in the xls, but I wanted to make sure. Something about the mass ratios being off?

Thanks for your hard work on the mod, I really enjoy it!

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What would be the best way to send in bugfixes?I imagine a pull request would be the ideal way to go about it though. I'll look into getting github setup for myself (I think I may have already). Some of the tantares configs need a little tweaking, but I haven't a list of what the issues might be yet.

Not to be a questioning pest, but what is the best way to handle a tank/engine combo? Where the engine is a part of the tank, I mean. That comes up in several places in that modpack. I think I see how in the xls, but I wanted to make sure. Something about the mass ratios being off?

Thanks for your hard work on the mod, I really enjoy it!

You can submit an issue in GitHub if you don't want to do a pull request, but pull requests would be super helpful! :)

The XLS is the best place to look for details, honestly. If there is an engine/tank combo (i.e. FASA's Centaur Transtage), figure out the engine stuff first. I always match the thrust, then choose a type based on the intended use (even if the ISPs go off a bit), and adjust the mass until it reaches the goal TWR in the right half. There is the tank column, where you'd specify the RF tank type and the volume (in liters). If you want to add some extra mass for the tank addition or some other unrelated piece, there's an extra mass column just for that, which will add that amount to the engine mass. The XLS just constructs the config for me so I don't have to write it all in by hand each time.

I don't have Tantares installed, so I wouldn't catch details about what's working. If you can make it better, please do!

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Almost have that ion engine config ready. All I have to do is figure out how to make atmospheric Isp affect thrust instead of fuel flow, double-check my electric charge ratio, and ponder if I'm really rebalancing it correctly. I was playing with Isp; I relented a bit from 1800s after looking up real Hall Effect and VASIMIR engines.

I was intending to let you build a probe based off a single engine, 4 Gigantors, 8 km/s total delta-V, and a 1000-charge battery which would make 2 km/s (approximately equivalent to a stock Jool transfer, minus Oberth considerations) in about 10-15 minutes at 4x timewarp. The current parameters I have are probably a bit generous for that design target, but it has to remain playable, and spending hours to make a single transit just isn't fun.

So, in short, how do you toggle Isp to function on thrust instead of fuel flow?

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You don't have to figure it out, RealFuels does that by default. :)

(As long as you add a ModuleEngineConfigs module, even if there's only one CONFIG.)

Thanks for the help! I was trying to avoid that so I wouldn't have to figure out how to write a ModuleEngineConfigs module, but it looks like I don't have much choice... and if I write a ModuleEngineConfigs module, I might as well write a few for different thrust/efficiency regimes (HighThrust, Default, LowThrust, Stockalike).

Also, the tip about ModuleEngineConfigs came with absolutely amazing timing: I clicked "reply to" within seconds of coming into the thread.

z6ugGKY.png

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Also, the tip about ModuleEngineConfigs came with absolutely amazing timing: I clicked "reply to" within seconds of coming into the thread.

That is impressive...

Also, feel free to rip the ModuleEngineConfig node out of one of the current engines, or abuse the XLS to get out what you need. No need to reinvent the wheel. You should just need to change the config names and the config's resources (obviously) and the ISPs. I'd avoid the tech levels, since that might scale everything oddly in comparison...

Edited by Raptor831
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The new LANTR config does not work for me, i am getting NullReferenceException spam and no option to set anything in the "Show Engine GUI" window (altough the window appears, it is empty). I have a ton of mods installed, so it is probably one of them interfering here, but i couldnt find anything yet. Have already reinstalled RF and Stockalike RF Configs.

I think i have found the culprit, it is HotRockets. (Makes sense, retrospectively.) I guess it modifies the original lv-n in a way that screws up the trimodal one, now if i only knew howto fix it...

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Success*! Kinda. Still have to rebalance electrical charge and a couple things, but I've got four configurations going: three "real" configurations running from 2.5N at 1800s Isp to 0.6N at 3500s Isp (subject to change), and one stockalike config which will only readjust electricity usage. One thing I noticed: the max fuel flow rate in the engine GUI is misleading: it uses the stock model where the effect of sea-level Isp is to increase fuel flow rate instead of decreasing thrust. It's rather noticeable when you have a vacuum Isp of 3500s and a sea-level Isp of 10s.

*You have no idea how long it took me to realize I'd misspelled "name = ModuleEngineConfigs" as "name = ModuleEnginesConfig"

Couple things. First off: am I correct in assuming that high Isp ion engines will have much higher electrical consumption per N of thrust, on account of momentum transfer being linear in velocity, while kinetic energy is quadratic in velocity? Second, do you know of any ion engine technologies which are functional in atmosphere (so people can still do crazy ion gliders)?

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I think i have found the culprit, it is HotRockets. (Makes sense, retrospectively.) I guess it modifies the original lv-n in a way that screws up the trimodal one, now if i only knew howto fix it...

That would be an excellent guess. To be clear, the normal LV-N works? But the trimodal does not?

In the meantime, try this for me: remove the ":BEFORE[RealFuels_StockEngines]" from the trimodal config. If that works, I think I know what's going on.

Success*! ..snip..

Awesome!

*You have no idea how long it took me to realize I'd misspelled "name = ModuleEngineConfigs" as "name = ModuleEnginesConfig"

I, sadly, have been in your shoes. :)

Couple things. First off: am I correct in assuming that high Isp ion engines will have much higher electrical consumption per N of thrust, on account of momentum transfer being linear in velocity, while kinetic energy is quadratic in velocity? Second, do you know of any ion engine technologies which are functional in atmosphere (so people can still do crazy ion gliders)?

First one is above my pay grade, but it sounds reasonable. Second, I don't think there is any electric-type propulsion that would work in atmosphere, simply because the thrust is so small. But hey, this is KSP, where we've added the Orion "rocket" (link, and source wiki).

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To be clear, the normal LV-N works? But the trimodal does not?

In the meantime, try this for me: remove the ":BEFORE[RealFuels_StockEngines]" from the trimodal config. If that works, I think I know what's going on.

Yes, exactly.

Woopwoop, this worked, and is somewhat more elegant than my "delete everything from Hotrockets that modifies the lv-n" approach ;) So whats going wrong there specifically...?

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Hey, ol' Bang-Bang works *great* in atmosphere. Don't be hatin' on ol' Bang-Bang!

I know almost nothing about electric propulsion, sorry. You'd best be served by talking to hoojiwanna or Nertea IIRC.

I'm not hating on ol' Bang-Bang. The concept works, and it's one of the most kerbal things we've ever come up with! Just don't be downwind from the launch site... :wink:

Yes, exactly.

Woopwoop, this worked, and is somewhat more elegant than my "delete everything from Hotrockets that modifies the lv-n" approach ;) So whats going wrong there specifically...?

Ok, what's going on is a loading order issue. The trimodal config doesn't fire until the :BEFORE[RealFuels_StockEngines] pass, and the HotRockets one fires on :FOR[HotRockets] (I think...) and that removes the stuff the trimodal config expects to find. Removing that reverses the order.

EDIT: I've updated the repo with this fix, but I haven't put it in a release yet. Anyone can either download the source from GitHub to get it or just make that change to fix it.

Edited by Raptor831
Repo update
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I've been pondering a large heavy lift methane/LOX engine to fill that role in Stockalike. Most likely this would be a 3.75m engine with those thrust numbers (or at least closer). Probably will do a part-copy alternate config for a NovaPunch or KW engine to do so, or maybe the KX-2 stock one. Most engines in this class don't even come close to 8000 kN, and the only ones that do are boosters from NovaPunch (which I might nerf a bit). If you want a straight Raptor clone, I imagine the RO thread has that somewhere.

Hey Raptor, I saw this a few (almost 3) weeks back when you posted it, but then haven't heard anything more about it since, or seen any related commits in the dev version of Stockalike.

I would LOVE it if you did include a 3.75 meter version of the Meth/LOx engine that actually did clone the real-world specs (or something closer to them) like you suggested to fulfill the heavy-lift role. A 2.5 meter engine simply isn't powerful enough to lift a 3.75 meter rocket... (unless you use the real-world Raptor stats for the 2.5 meter version)

It's worth noting that there were a couple reasons the Raptor stats are way out of line with the XLS for 2.5 meter engines. One is because almost all the engines in KSP produce less thrust than their real-world analogs, and have inferior TWR values (real rockets are much taller, and thus require much better engines, due to the greater Delta-V requirements to reach orbit).

The other is because the Full Flow Staged Combustion cycle used in the Raptor is a MUCH more advanced engine design that almost any other engine out there. I think there were ever only 2 other engines that were designed to use it, and neither of them made it off the test stand (although they DID work as expected in testing) as there was no need for an engine that powerful (its greatest advantage is that it makes re-usable rocket stages much easier when you have an engine that powerful- but nobody ever seriously attempted reusables until Space-X) and it is significantly more expensive to engineer in the first place (but not to build- a higher but-in cost in the tech tree is the best representation for this)- something that also deterred its development until Space-X's efforts at reusability...

Also, that engine design doesn't offer very substantial benefits when using LH2/LOX- so most rocket designers preferred to just stick with LH2/LOX for high-performance launch stages, rather than move to Kero/LOX or Meth/LOX engines with a Full Flow Staged Combustion Engine (I should note that LH2/LOX is a poor choice for reusable launch stages, due to its low fuel density- it makes it difficult to build a launch stage with a low enough Center of Mass that it won't tip over after touch-down, an issue Space-X is currently struggling with despite using Kero/LOX- they already lost one launch stage in a recovery test to it tipping over in the sea and the fuel tank rupturing...)

I should note I launch almost all my rockets Space-X style in KSP, so I would LOVE to have a Full Flow Staged Cumbustion engine at my disposal, even if its tech tree buy-in costs (I play with those enabled) were considerably higher than other chemical rocket engines... (the per-unit cost shouldn't be, however- the engines aren't actually harder to manufacture, only design)

Anyways, enough tangents about the performance aside. I deeply hope you'll follow up on this idea you mentioned before.

Also, some investigation reveals the KSP-Interstellar Al-Hybrid TWR and ISP are, surprisingly, perfectly accurate already. Several design limitations about how the Aluminum can be packed in (in such a way that the Aluminum can be replaced via ISRU, as it can be in the KSP-I version) tend to increase its dry mass substantially (leading to a rather low TWR compared to what can theoretically be achieved with this propulsion system...) Thus the current TWR is spot-on with design projections, as far as I can tell... I know you asked about this before, and I wanted to follow up with this information.

Thanks for all your hard work so far! :)

Regards,

Northstar

Edited by Northstar1989
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@Northstar1989: I've noticed the Space-Y engines on the add-ons forum. These, I think, are perfect to include a methalox config, since they are a psuedo-SpaceX derivative. They're 5m I think, but that should fit the bill! Maybe this weekend I'll add those in to the config (and my own install!!).

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@Northstar1989: I've noticed the Space-Y engines on the add-ons forum. These, I think, are perfect to include a methalox config, since they are a psuedo-SpaceX derivative. They're 5m I think, but that should fit the bill! Maybe this weekend I'll add those in to the config (and my own install!!).

Link please. MUST SEE! :D

Seriously, though, they might have the same problems with incorrect ISP/TWR values. No idea if they based those off the real engines or not...

By the way, I noticed that the changes to fix the Meth/LOX engine ISP (and slightly improve the TWR to be more realistic) aren't currently part of the latest version on GitHub as far as I can tell. Didn't you say you already fixed that (in the same post I quoted before) some time ago?

In fact, the current GitHub and Release versions of "Stockalike" don't have MM patches for the engine at all as far as I can tell! (meaning the engine won't work in RealFuels at all, as the engine uses Oxidizer without a MM patch...) I'm using an older version of "Stockalike" still until this issues is resolved, but I also need to update so that my RAPIER and NovaPunch2 M2 engines won't burn Oxidizer as well- so please update soon!

Regards,

Northstar

Edited by Northstar1989
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