[0.90]Kerbal Isp Difficulty Scaler v1.4.2; 12/16/14

[Blipser]

There seems to be a bug when using MFS tech levels resets the engines isp to what MFS says it should be, not the resealed one.

[m4ti140]

Hmmm... I know KIDS is not compatible with Real Fuels, but using a combination of FAR, DRE, KIDS, RF and AJE gave me some... interesting results .... I set the stock Aeris 3A to Kherosene, adjusted flight surfaces and launched it....

I staged the engines and carefuly set thrust to ~10%. Now, you think that combination of mods lowered my thrust to something miserable? WRONG! 10% thrust was enough to eject from the runway at 10g... almost causing the fuel tank to explode due to heating when I reached Mach 2 at 1500m ASL... Whiskey Tango Foxtrot? This also applies to rockets, so it's probably unrelated to AJE...

Is there any chance for this to get updated? I don't want my planets to be changed just to have proper aerodynamics AND jet engines (without stuff feeling cheaty)

[Kitspace]

The description of the Real Fuel mod says that I can use a low KIDS multiplier with the mod to get realistic performance with game stock solar system.

So, I have installed the RF mod, FAR mod, and KIDS, and I have a very big problem.

With the Thrust Varies with Isp option enabled in the menu, the less Isp multiplier I use, the more power I get.

With multipliers set to half or less, I get my kerbals killed by huge excecive G-force.

What could possibly happen and what could I do?

[ferram4]

KIDS integration with RF has been on the back burner for a while, so that's questionable to begin with. However, what it sounds like is that you're building your rockets without regard for the gForces at stage burnout. There's a reason real rockets start with low initial TWRs and shut down / throttle some engines near stage burnout. It's a design issue, built your rockets to use performance closer to real life rockets rather than KSP rockets.

[Kitspace]

That is certainly not a rocket construction issue, because, as I have said, I make the multiplier less which should decrease my Isp, but for some reason, I get much more power in the very same situation.

If that is as it is supposed to be, than I am really confused with what this mod does with my engines.

Or, this is caused by the real fuel somehow...

What settings do I need to use, to get the proper result with it?

Do I need the realistic Isp handling on or off?

If it is disabled, the whole combination seems to work, but this way I do not get how could it affect performance in any way, as the game stock parameter affects fuel consumption, but not thrust, at least the mod description makes me believe that it is made that way. So, how is it supposed to prevent my rockets from being overpowered for stock Kerbin, if I use real fuel?

And a question about the general purpose of this mod, disregarding the real fuel mod, that makes thing lighter. If parts in the game are much heavier than in real life, why do we need to throttle down, even with a smaller planet?

Edited May 12, 2014 by Kitspace

[jeffjeff]

Hey Ferram,

I've been playing with FAR, KIDS, and DREC and it's been loads of fun. Thanks for all of your hard work. I'm learning loads about rocketry. Anyway, I prefer playing stock KSP solar system, so I was wondering if anyone could help further explain the two presets for that in KIDS.

First, I don't understand why 'FAR to Stock KSP, Universal' penalizes vacuum ISP. I'm using FAR and KIDS to get more realistic rocketry in an atmosphere, but wouldn't I want my ISP's to basically be stock once I'm in space.

Next, I see that 'FAR to Stock KSP, Atmosphere Only' is an answer to my first question, but why does it penalize me so much in an atmosphere? It makes my rocket designs super tall like this http://i.imgur.com/WKAjehd.jpg?1 (I also don't have many parts unlocked. Just a few nodes on the tech tree.)

Would a happy medium be more suitable for me? Maybe I should adjust the settings to allow thrust to vary with ISP. I just don't know too much on that subject or how the game handles things like vac/atm rated engines.

Thanks!

[velusip]

I noticed that the mod has some functionality to check for and warn about conflicts, and currently detects "ArcturusThrustCorrector". It's worth Adding "AJE" and "modularFuelTanks" to that list of checks.

Edited May 16, 2014 by velusip
added links

[Makrond]

Hey Ferram,

I've been playing with FAR, KIDS, and DREC and it's been loads of fun. Thanks for all of your hard work. I'm learning loads about rocketry. Anyway, I prefer playing stock KSP solar system, so I was wondering if anyone could help further explain the two presets for that in KIDS.

First, I don't understand why 'FAR to Stock KSP, Universal' penalizes vacuum ISP. I'm using FAR and KIDS to get more realistic rocketry in an atmosphere, but wouldn't I want my ISP's to basically be stock once I'm in space.

Next, I see that 'FAR to Stock KSP, Atmosphere Only' is an answer to my first question, but why does it penalize me so much in an atmosphere? It makes my rocket designs super tall like this http://i.imgur.com/WKAjehd.jpg?1 (I also don't have many parts unlocked. Just a few nodes on the tech tree.)

Would a happy medium be more suitable for me? Maybe I should adjust the settings to allow thrust to vary with ISP. I just don't know too much on that subject or how the game handles things like vac/atm rated engines.

Thanks!

I'm not ferram, but the reason the FAR to stock, universal preset penalises flying in a vacuum is to try and spread the load of 'paying off' the extra delta-v you gain from being able to fly a more efficient ascent across both your atmospheric flight and your vacuum flight. The reason the adjusted preset has such a heavy penalty for flying in atmosphere is that it has to front-load this same ~1000dV penalty to the first 35,000m of altitude, before the atmosphere becomes so thin as to not affect your Isp anymore. Generally speaking it shouldn't significantly affect your rocket design compared to the universal preset (since the idea is to make you carry more fuel into orbit, meaning you need more fuel and possibly thrust in your lifter), but your ascent may need to be more vertical to get enough efficiency out of those engines to reach orbital speed before you run out of fuel.

[jeffjeff]

Thanks Makrond, that makes perfect sense. I'm going to go rework my rocket designs and play with the 'Thrust Corrector' settings. I'm also guessing that the 'Extend Curve to Zero Isp' setting will only take affect in atmospheres with pressures greater than 1 atm. So theoretically, I may get engines that don't work at all (0 Isp) on the surface of Eve for example. Am I correct in that thinking?

[Berengal]

I've found a bug in the interaction between KIDS and Procedural Parts, specifically the procedural SRB. The procedural SRB lets you choose (among other things) the thrust and ISP (surface nozzle or vacuum nozzle) of the part. If KIDS is set up to vary thrust depending on ISP then this will usually (but not always) give the SRB the wrong thrust and ISP. The ISP will be the ISP specified on the part in the VAB, and the thrust will be the default thrust of the SRB (250kN) multiplied by the inverse of the ISP multiplier.

As I said, it doesn't happen consistently, but it happens pretty often when launching a new vehicle. Reverting to launch will usually, but not always, fix the issue.

I don't know how either of these mods work internally, but it looks to me like sometimes on launch, KIDS updates the ISP and fuel-flow using the default values of the SRB part. Procedural Parts will then overwrite these when it gets to run, but since KIDS is set to vary thrust with ISP it will continuously overwrite the thrust so the fuel-flow remains constant at the erroneous value it calculated when it ran first. It doesn't notice the ISP has been updated, so the result is a high fuel-flow, high ISP (= high thrust) engine and rockets with launch TWR of about 20 incinerating before they reach 10km.

[velve]

Seems there has not been a reply in a while but got a quick question, Does KIDS play nice with -Real Solar System, Realism overhaul, Listed Realism overhaul mods, Realistic Progression lite and all its submods?

Yes I may have fallen for the "realism" trap, but I'm really enjoying them and was just wondering if KIDS enjoys them too? Because of the scaling I figured there might be some issues, as I am not mathematically inclined, I tend to learn the mechanics of something through constant use and trial and error, If a mod causes balance issues I will not even notice it and struggle on for ages since I'm not completely clued up with the mechanics behind KSP just yet.

[ferram4]

KIDs currently does not play well with Real Fuels, and probably not with Procedural Parts either. As in, either it will not do anything or it will break horribly.

[NathanKell]

Instead you can manually edit the RealSettings.cfg file, reducing Isps as appropriate. That will change Isps for all techlevel-enabled engines.

[velve]

Thanks for the response..... I have opened the realsettings.cfg and found this

%useRealisticMass = true

%tankMassMultiplier = 4.807692308

%engineMassMultiplier = 3.2

%heatMultiplier = 1.0

MFS_TECHLEVELS

{

ENGINETYPE

{

name = O

TLISP0

{

key = 0 286

key = 1 100

}

TLTWR0 = 18.9

TLTECH0 = start

TLTHROTTLE0 = 1

TLISP1

that is generally what repeats, what do I need to change? And what would be a good value?

again thanks

//I seem to have gone horribly wrong somewhere along the line, I followed instructions word for word branching out from the real solar system mod for all its compatibilites yet, I just had a run through after getting some larger engines and it feels like they are on rails. To explain in more detail, when I activate the launch phase my rockets have the resemblance of a very stiff rocket going up at 3X warp speed in vanilla KSP, I get up to 500m/s within a few seconds...there is no feel or emotion attached to a launch at all anymore. Somewhere I have a conflict and I'm a bit tired now to sift through it all. My lack of understanding of all the terms and effects is also not helping.

here is what I currently have running

Sorry for intruding on this thread, I will gladly remove this in the morning and post it in a more appropriate section but for now I have to hit the hay if anyone spots the culprit feel free/please pm me

Edited June 21, 2014 by velve

[NathanKell]

velve: see all the key = 0 xxx lines? Those are vacuum Isp. The key = 1 xxx lines are sea level Isp. So for each key = 0 xxx, scale the xxx by what you'd use as your vacuum multiplier in KIDS. I.e. if it's 1.5, then you'd change the 286 you show to 429. Scale the xxx for all key = 1 xxx lines by what you'd use as your atmospheric multiplier.

As for your other issue, it sounds like you're not used to how much more thrust, comparatively, RF engines pump out. Realistic launchers have a sea level liftoff TWR in the 1.15 to 1.5 range (unless they're solids, of course)--aim for that.

[velve]

Thanks for the help nathan....unfortunately I feel I need to familiarize myself with the game mechanics a bit more before I start scaling etc. I know it can be explained but I just feel like I'm not getting it

So I reverted to stock KSP with a few mods namely FAR and KIDS and I'm having this problem.

Using the settings FAR to real life Adjusted, surely this rocket should get me to MUN? I can only get halfway and that is with multiple launches testing different speeds. Or is the KIDS mod scaled in a way that you would actually need a rocket the size of saturnV to get to the moon?

Sorry for being a pain.

[ferram4]

Well, once of your problems is unnecessary stages. You can get rid of the second skipper and combine that into a single stage and you will get more dV as a result. You should also be able to make your 1.25m stage run on an LV-909 and increase dV that way, you don't need that high a TWR once you're in space.

And KIDS Adjusted to Real Life does mean that if you want to go to the Mun and come back, using LOR rather than EOR or direct ascent you will need a Saturn V for a manned mission. An unmanned, one-way mission should be about fine with an adjusted version of that.

[velve]

Ok, I understand thank you very much

Still learning you see. btw FAR is working beautifully now what a great mod thank you! It was a scaling problem previously.

[LostOblivion]

Does this work with 0.24?

[ferram4]

It certainly does now.

[flashcactus]

Please fix the kerbalstuff link by removing the /publish/ at the end.

[ferram4]

It is fixed.

[enneract]

Bug report for .24 - an additional stock toolbar button is added after each flight ends.

[ferram4]

A hotfix has been pushed for that issue.

[Desrtfox]

Amazing speed with the hotfix. thanks!