[1.8+] Real Fuels

[J_Davis]

I don't know if it's only me, but as a user of stock-alike engine config, my idea is: don't change too much to the original game-play. Providing more options however is always welcomed. i.e. don't change the default propellant RCS ports use, but provide configs using other types of propellents in the RCS port's configuration dialog.

And to make those options like "Hydrazine" attractive, since they are tougher to use (not transferring through ALL_VESSEL), you can give some advantages (like higher Isp, higher max thrust, part being lighter etc.) to it, or nerf the MonoPropellant mode a bit also.

Plus, if you can make RCS port thrust tweakable that would be even better, especially when satellites need real small thrust to accurately adjust its orbit. (Though this was already doable by my TP plugin, but i guess that MFS will call RCS port's Load() right after the flight starts, so the thrust value tweaked by TP plugin might be overwritten again)

Hmm, we might need different 'stockalikes' then. I personally like the idea of having to have Hydrazine in each area where I have RCS burning and want things like Mono-propellant removed. I think it's a case of everyone wanting a slightly different experience.

[NathanKell]

Ah, then your approach *is* to change mass? Cool. Guess I'll keep the original around in case there's enough people who do choose option 1 in the poll.

They did, but I think that's an artifact of hydrolox: they burn a well leaner than optimum (in Isp terms) mixture ratio in order to lower stage size and take advantage of increased thrust from more mass flow for same volume (turbopumps push volume, not mass); once the stage TWR doesn't matter as much (in orbit, or current gross mass is lowered enough during the burn for S-II) they can rich it up to closer to Isp-optimal ratio.

Note that the J-2 had a comparatively low expansion ratio, so the Isp-optimal mixture ratio was about 4. For reasons of enhanced fuel flow (thrust) and lowered volume required they ran quite lean (as do most hydrolox engines).

Eventually I'll get my sheet working to automate RCS config building too. For now, you can just nick them from RO (RCS ports keep their original sizes, other than the two new mini ones).

And yes, I'm thinking more and more I should have just switched to HTPB and PBAN, and ditched SolidFuel.

Great!

EDIT: Ninja'd twice...

HoneyFox: that's why I added two tiny (1/4 and 1/2) RCS blocks to RO. I'm currently writing up the configs for KW and AIES and RLA RCS. As I said above to J_Davis, you can nick them from RO, they aren't RO-sized.

[J_Davis]

I'm leaving the mass alone as much as possible and toying with the ISP curves to get the TWR near TWRG for the role. At present, I'm only changing the mass of one engine and the thrust of another.

And I'll have to snag that RCS changer!

[rottielover]

I agree with HoneyFox. See what I don't like about realism overhaul is the re-scaling. The Mk1 pod becomes 2m and no longer fits with most mods or stock parts. My preferred mode of play right now is inspired by Scott Manely's Intersteller series. I'm using mods like Deadly Reentry, TAC life Support, FAR, Real Chutes, etc. Trying to make KSP more realistic, without loosing the game feel. Re sizing the parts kinda sucks the game feel away since the parts don't fit with the others, and it adds that many more decouplers and stuff. Hopefully this is making sense.

[rifter]

The B9_modularEngines.cfg in RealFuels 4.1 sets the B9_Engine_SABRE_M to have really high thrust (2940), while not touching the thrust of the B9_Engine_SABRE_S (defaults to 215). Out of curiousity, what is the reason for this engine being given so much thrust?

[Starwaster]

The B9_modularEngines.cfg in RealFuels 4.1 sets the B9_Engine_SABRE_M to have really high thrust (2940), while not touching the thrust of the B9_Engine_SABRE_S (defaults to 215). Out of curiousity, what is the reason for this engine being given so much thrust?

Because that's the planned thrust of the actual SABRE engine that's under development. As for the smaller engine, smaller chamber, lower mass flow so less thrust.

[HoneyFox]

Ah, i would give a note here to NathaneKell and SFJackBauer and perhaps other author(s) of engine configs:

In the next EI version, ModuleEngineIgnitor will have a new boolean parameter "isPressureFed" (default: false) which controls whether an engine is pressure-fed or not.

The possible combinations are:

Engine             Fuel Tank          Situation
 Pressure-Fed       Pressurized        No ullage issues when igniting.
 Pressure-Fed       Non-Pressurized    Very hard to ignite and will flame-out immediately even if ignited.
 Non-Pressure-Fed   Pressurized        No ullage issues when igniting.
 Non-Pressure-Fed   Non-Pressurized    Ullage issues exist. Prepare ullage motors or other measures.

Here is one question about checking if pressurized fuel tank is present.

I'm now trying to scan all fuel tanks by using part.GetConnectedResources(), and the question is: should i consider it present if a fuel tank is pressurized but with no resource inside. i.e. does an empty pressurized fuel tank count? it sounds weird but some people might use a small service-module fuel tank with a big non-service-module fuel tank.

For the old "useUllageSimulation" parameter in ModuleEngineIgnitor, it was used by engines (normally small) that we don't need to worry about ullage issues. Once the next version gets finished, it should be used as a cheaty switch for certain engines.

Edited January 6, 2014 by HoneyFox

[rifter]

Because that's the planned thrust of the actual SABRE engine that's under development. As for the smaller engine, smaller chamber, lower mass flow so less thrust.

Ah, ok, I kinda suspected that might be the situation. I was expecting the engine thrust to be set to similar to stock (as stock as a mod can be, anyways) when using the "Stockalike" config. Thanks for the info.

Edited January 6, 2014 by rifter

[J_Davis]

Stockalike work doesn't touch the SABRE, IIRC.

Anyway, I was hoping to hear from Chest before doing this, but I really want to get rid of those MFS 3.3 configs. But I'm going to make the pre-release v4.1 stockalikes available

https://www.dropbox.com/s/19jl7lts1m6xe6q/Stockalike_RF_Engines.cfg

Supports:

Stock Engines

KW

AEIS

Engines that come with RF

Does *not* support:

B9

FASA

NTRs

RCS

Please let me know what you think.

[Starwaster]

Ah, i would give a note here to NathaneKell and SFJackBauer and perhaps other author(s) of engine configs:

In the next EI version, ModuleEngineIgnitor will have a new boolean parameter "isPressureFed" (default: false) which controls whether an engine is pressure-fed or not.

The possible combinations are:

Engine             Fuel Tank          Situation
 Pressure-Fed       Pressurized        No ullage issues when igniting.
 Pressure-Fed       Non-Pressurized    Very hard to ignite and will flame-out immediately even if ignited.
 Non-Pressure-Fed   Pressurized        No ullage issues when igniting.
 Non-Pressure-Fed   Non-Pressurized    Ullage issues exist. Prepare ullage motors or other measures.

Here is one question about checking if pressurized fuel tank is present.

I'm now trying to scan all fuel tanks by using part.GetConnectedResources(), and the question is: should i consider it present if a fuel tank is pressurized but with no resource inside. i.e. does an empty pressurized fuel tank count? it sounds weird but some people might use a small service-module fuel tank with a big non-service-module fuel tank.

For the old "useUllageSimulation" parameter in ModuleEngineIgnitor, it was used by engines (normally small) that we don't need to worry about ullage issues. Once the next version gets finished, it should be used as a cheaty switch for certain engines.

If I understand the question and the problem correctly, my first reaction would have to be no, doesn't count.... but is that function meant to return other parts in the stack or fed by fuel lines? If so then it should definitely pass those because it should be assumed it has plumbing pass through....

[NathanKell]

Somebody asked me to give the SABRE (the M is the actual real-life SABRE) real-life stats.

This basically comes of my not having had a chance to *actually* support spaceplane stuff (jets and SABREs) in RFv4 yet. I have half the code there, but we spent so much time updating for .23 that I had to push it off for the next big release.

HoneyFox: IMO unless all tanks from which a PF engine can draw resources are pressurized, then it should flame out. Otherwise you can keep one little pressurized tank and one big unpressurized tank and either constantly manually transfer or use a fuel line.

J_Davis: Cool! Just from spot-checking, though, I note you kept the Skipper as type U. Intentional? In stock KSP it's pretty clearly a booster (the 2.5m L+, maybe?)

[TomatoSoup]

I have some possibly incompetent questions.

I was lead to believe there were multiple fuels for RCS, or is that just an option for modmakers? Also, my Shuttle Engines aren't configurable for different fuels despite them being on a list of compatible things? Or is that a Space Shuttle system other than the Klockheed Martian one (that doesn't seem right as the fuel tanks are certainly compatible)? Same for the FTmN rockets except for the stockalike double nerva, so I suppose support there just isn't finished.

I've gotta say, some more explicit instructions and notes (like compatible mods) would be helpful, as I've got it at least half working and I'm not sure if I'm making a mistake or somethings just aren't implemented yet. Like, for instance: The readme suggests using cryogenic tanks with cryogenic fuels, which makes perfect sense, but I have no idea how to tell if they're cryogenic or not, or if I'm supposed to find a button that insulates them.

Edited January 7, 2014 by TomatoSoup

[HoneyFox]

HoneyFox: IMO unless all tanks from which a PF engine can draw resources are pressurized, then it should flame out. Otherwise you can keep one little pressurized tank and one big unpressurized tank and either constantly manually transfer or use a fuel line.

Well since even if i make the engine flame-out if any of its connected tanks is not pressurized, players can still use something like TAC Fuel Balancer to automatically transfer fuel from a non-pressurized tank into a pressurized tank. and there's no direct/indirect connection between that non-pressurized tank and the engine (i.e. not on a stack or something not fuel-crossfeed in the stack, and no fuel line used). hence there's still trick that can work.

[rottielover]

I have some possibly incompetent questions.

I was lead to believe there were multiple fuels for RCS, or is that just an option for modmakers? Also, my Shuttle Engines aren't configurable for different fuels despite them being on a list of compatible things? Or is that a Space Shuttle system other than the Klockheed Martian one (that doesn't seem right as the fuel tanks are certainly compatible)? Same for the FTmN rockets except for the stockalike double nerva, so I suppose support there just isn't finished.

I've gotta say, some more explicit instructions and notes (like compatible mods) would be helpful, as I've got it at least half working and I'm not sure if I'm making a mistake or somethings just aren't implemented yet. Like, for instance: The readme suggests using cryogenic tanks with cryogenic fuels, which makes perfect sense, but I have no idea how to tell if they're cryogenic or not, or if I'm supposed to find a button that insulates them.

Hey I'm in the same boat as you. Here's the scoop: The Engine config files don't contain everything. I've found that the bigger shuttle engines are supported, but the small (micro) ones are not. Same with the RCS, I was told a few posts ago that RCS wasn't included with the stockalike engine configs.

[J_Davis]

Somebody asked me to give the SABRE (the M is the actual real-life SABRE) real-life stats.

This basically comes of my not having had a chance to *actually* support spaceplane stuff (jets and SABREs) in RFv4 yet. I have half the code there, but we spent so much time updating for .23 that I had to push it off for the next big release.

HoneyFox: IMO unless all tanks from which a PF engine can draw resources are pressurized, then it should flame out. Otherwise you can keep one little pressurized tank and one big unpressurized tank and either constantly manually transfer or use a fuel line.

J_Davis: Cool! Just from spot-checking, though, I note you kept the Skipper as type U. Intentional? In stock KSP it's pretty clearly a booster (the 2.5m L+, maybe?)

Quite intentional. There were a dearth of U's rather than U+'s IMO. So I picked a few reasonable 'U-like' engines.

[AbeS]

Are all the stock alike engines fully throtteable? Or they are more realistic?

[HoneyFox]

Are all the stock alike engines fully throtteable? Or they are more realistic?

Currently there's no minThrottle settings in stock-alike engine config. Don't know if it will be added in later version.

Anyhow, that will be quite a big challenge... perhaps mainly on G-load assessment, with tools like KER/MJ that shouldn't be too hard.

[rifter]

Somebody asked me to give the SABRE (the M is the actual real-life SABRE) real-life stats.

This basically comes of my not having had a chance to *actually* support spaceplane stuff (jets and SABREs) in RFv4 yet. I have half the code there, but we spent so much time updating for .23 that I had to push it off for the next big release.

Yeah, spaceplanes are really hard to get going in RSS, so that makes sense. That they will be properly supported (eventually) is great news, though. Thank you for all the time you put into this mod

[J_Davis]

Currently there's no minThrottle settings in stock-alike engine config. Don't know if it will be added in later version.

Anyhow, that will be quite a big challenge... perhaps mainly on G-load assessment, with tools like KER/MJ that shouldn't be too hard.

There are some in the v4 prerelease configuration.

[HoneyFox]

There are some in the v4 prerelease configuration.

oh? can you tell me one of these engines so i can check if i'm using the latest version. (well i made some modification myself so i cannot just simply overwrite the file directly)

[J_Davis]

oh? can you tell me one of these engines so i can check if i'm using the latest version. (well i made some modification myself so i cannot just simply overwrite the file directly)

https://www.dropbox.com/s/19jl7lts1m6xe6q/Stockalike_RF_Engines.cfg < Is the config, as I stated before, it supports KW, AEIS, and Stock engines.

In general, L type engines will have to have a techlevel of 3 more than their base to be throttleable. L+ and U require a techlevel of 2 more than base to be throttled. U+ and A require a +1 to their base tech level, and O are inherently throttleable.

Try the mainsail at the lowest tech level it will come at, it will refuse to throttle.

[xZise]

Hi, yeah I noticed yesterday that my Skipper wasn't very throttleable. I have to check if it is visible somewhere and I didn't noticed it but otherwise there should be a info in what ranges you can throttle the engine (I was able to either shut it down or throttle at higher levels so there appears to be at least some throttle). Unfortunately you can "cheat" by rapidly turning the engine on and off to get a lower average thrust. I don't know if you want to add any "restartability" to it which might make this impossible.

But I also noticed something else. In J_Davis prerelease the mixtures between engines is different. Maybe help the builder and add the percentages of the mixture somewhere when I edit the engine.

Fabian

PS: Okay I took a look at the second image and there is a MinThr info so maybe I didn't look carefully (although I never had an liquid fuelled engine before which weren't throttleable.

[Silpion]

Pretty glorious.

Any chance of the awesome LazTek SpaceX Launch Pack getting real-sized? I'd love to do an actual Dragon moon landing using those Falcon Heavy's etc.

[AbeS]

Some SpaceX engines are resized in RealEngines

[J_Davis]

But I also noticed something else. In J_Davis prerelease the mixtures between engines is different. Maybe help the builder and add the percentages of the mixture somewhere when I edit the engine.

Yeah, this is important and handy. I generally work-around by using different fuels-oxidizers pairs for every stage, but if you try to use the same fuel-oxidizer throughout, you have to do some fiddling to make sure you're using the right mixtures on the right stages.

However, if you pay attention to engine types, here they are in order from RICHEST to LEANEST: (Whups! Had that backwards. The file is set with A the richest and O the leanest.)

A, L, L+, U, U+, O

So if you have a 1st stage using a kerolox aerospike and a 2nd stage using a kerolox U engine, the U engine takes the setting that uses more LOX.

I can always make the mixes identical if there's a lot of demand for it, but I think it's interesting to have different mixes for different stages (along with different fuel availabilities).

Edited January 8, 2014 by J_Davis