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  • Tuning changes in 1.6

    Maxsimal

    By Maxsimal

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    1.6 has brought a lot of great changes, and we’re really thrilled with what the team has created for it. One of the changes that we've done, and something we felt strongly about doing, was tuning work that we felt would improve the quality bar of the game.


    Craft Improvements
    First, we've gone through all the stock craft, including VAB, SPH, and Making History craft, delivered for the game, with an eye toward updating them for the new parts that have been released in 1.6, and also improving the fly-ability of many of our craft.  At one point, the idea was to have some of these stock craft have flaws for the player to correct.  This did not have broad awareness in the community,  so we've improved the flight behavior of quite a few of our craft - including using features like auto-strutting that weren't around when they were first added to the game.

    In particular, all of our space planes - the Learstar, the Dynawing, and the Slim Shuttle - have been fine tuned to improve their control behavior.  They're still challenging to fly, of course, but you don't have to fight their controls quite so much.  We've also strutted and improved the fly-ability to craft like the Albatross, Muna 1 & 2, the Acapello and several others.  We encourage you to check the 1.6 change log for the full list.

     

    Making History Engine Rebalancing
    The other major change was adjustment to the tuning of a number of Making History parts - especially the engines.  The engine changes in particular may be more controversial, and we'd like to explain the rationale behind them. 

    The overall goal here is to put all the Making History engines in line with base game tuning.  To let them have their own niche, and to neither obsolete nor be obsoleted by other engines.  And generally, engines that are either bigger, or more specialized, will be unlocked deeper in the tech tree.  Finally, we’re trying to make as few changes as needed, so that they won't drastically change the purpose of an engine.

    NOTE: For all stats in tables - a green background indicates an improvement over the current version, a red background means it was worsened.

     

    Small ASL Engine Tuning
    First, let's look at the smaller ASL engines. There are three Making History engines in this size category - the Skiff, the Bobcat and the Kodiak.  Here are the relevant stats vs similar base game engines:

     

    Engine Comparison Thrust (Vac) ISP Vac ISP ASL Mass Vac TWR ASL TWR Cost/kN Thrust Tech Level Gimbal EC/s Crash Tolerance Cost Entry Cost
    Reliant 240 310 265 1.25 19.57 16.73 4.58 General Rocketry (3) 0 7 7 1100 3200
    Swivel 215 320 250 1.5 14.61 11.41 5.58 Basic Rocketry (2) 3 6 7 1200 3500
    Thud 120 305 275 0.9 13.59 12.25 6.83 Advanced Rocketry (4) 8 0 7 820 3500
    Vector 1000 315 295 4 25.48 23.87 18 Very Heavy Rocketry (8) 10.5 3 7 18000 115000
    Current Kodiak 240 305 265 1.25 19.57 17.01 5.42 Heavier Rocketry (6) 0 3 6 1300 4200
    New Kodiak 260 300 285 1.25 21.2 20.14 4.23 Heavier Rocketry (6) 0 5 9 1100 4400
    Current Skiff 300 330 265 1 30.58 24.56 5 Heavier Rocketry (6) 2 3 6 1500 4500
    New Skiff 300 330 265 1.6 19.11 15.35 7.67 Heavier Rocketry (6) 2 3 7 2300 9200
    Current Bobcat 400 310 290 2 20.39 19.07 5 Heavier Rocketry (6) 5 3 6 2000 6000
    New Bobcat 400 310 290 2 20.39 19.07 5 Heavy Rocketry (5) 5 8 12 2000 800

    Kodiak:  Overall, the Kodiak need the most adjustment - it’s just entirely matched or outclassed by the Reliant, which appears earlier in the tech tree as well.  Therefore, and in keeping with its real world equivalent then RD-107, the Kodiak's stats were adjusted to give it a much better ASL ISP, a lower cost per kN of thrust, and a better durability.  This gives it a niche as a 1.25m liquid fueled booster, leaving the Reliant as the more general purpose no-gimbal engine.  The extra specialization helps to keep it at Heavier Rocketry, however, to match its historical partner, the Cub.

    Skiff: The Skiff's tuning is closer to ideal , but it turned out to be *too* good in too many categories categories - more efficient, better TWR, and lower cost/kN than other engines.  It occurs later in the tech tree, so we've chosen to keep its high efficiency at the cost TWR and cost. Now it’s a great sustainer-category engine - its ASL ISP and cost won't justify its use as a main engine anymore, but it’s fantastic as the center stage with some SRBs or Kodiak-powered boosters.

    Bobcat: The bobcat had tuning most in line with the stock, so few changes were made.  It got sturdier, and it moved earlier in the tech tree to give another ASL option in Heavy Rocketry, as we felt the end of the tech tree was getting crowded.

     

    Large ASL Engine Tuning
    Then let’s look at bigger ASL engines:  In this category we have the Mastodon. 
    Note: The stats for the Twin Boar reflect what they would be without the built-in tank.

    Engine Comparison Thrust (Vac) ISP Vac ISP ASL Mass Vac TWR ASL TWR Cost Cost/kN Thrust Tech Level Gimbal EC/s Crash Tolerance Entry Cost
    Vector 1000 315 295 4 25.48 23.87 18000 18 Very Heavy Rocketry (8) 10.5 3 7 115000
    Mammoth 4000 315 295 15 27.18 25.46 39000 9.75 Very Heavy Rocketry (8) 2 12 20 115000
    Twin Boar 2000 300 280 6.5 31.37 29.27 11250 5.63 Heavier Rocketry (6) 1.5 0 20 65000
    Mainsail 1500 310 285 6 25.48 23.43 13000 8.67 Heavier Rocketry (6) 1.5 12 7 38000
    Skipper 650 320 280 3 22.09 19.33 5300 8.15 Heavy Rocketry (5) 2 10 7 14000
    Current Mastodon 1350 290 280 5 27.52 26.57 22000 16.3 Very Heavy Rocketry (8) 5 3 6 135000
    New Mastodon 1350 305 290 5 27.52 26.17 8000 5.93 Very Heavy Rocketry (8) 5 8 15 32000

    Mastodon: The current Mastodon has no niche, being outclassed in all categories by other large engines, and being really expensive to boot.  The new Mastodon therefore become both more efficient and significantly cheaper.  Now it is an ASL workhorse that doesn't perform QUITE as well in Vacuum as engines like the Vector and Mainsail, but it’s more flexible and a little more efficient than the Twin Boar, without quite matching the Twin Boar's amazing TWR and cost.

     

    Vacuum Engine Tuning
    Next we've got the vacuum engines:  In this category we've got our most controversial engine, the Wolfhound, as well as the Cheetah.  

    Note: For this chart, ISP ASL is not listed - with good reason.  It just doesn't matter for engines that are almost exclusively used in a vacuum, it's not a significant balance criteria.

     

    Engine Comparison Thrust (Vac) ISP Vac Mass Vac TWR Cost Cost/kN Thrust Tech Level Gimbal EC/s Crash Tolerance Entry Cost
    Terrier 60 345 0.5 12.23 390 6.5 Advanced Rocketry (4) 4 0 7 1600
    Poodle 250 350 1.75 14.56 1300 5.2 Heavy Rocketry (5) 4.5 8 7 4200
    Rhino 2000 340 9 22.65 25000 12.5 Very Heavy Rocketry (8) 4 12 7 68000
    Current Wolfhound 375 412 2.5 15.29 1680 4.48 Heavy Rocketry (5) 3 8 6 6200
    New Wolfhound 375 380 3.3 11.58 3000 8 Very Heavy Rocketry (8) 3 8 6 12000
    Current Cheetah 125 345 1 12.74 1000 8 Heavier Rocketry (6) 3 3 6 3000
    New Cheetah 125 355 1 12.74 850 6.8 Heavier Rocketry (6) 4 5 7 3400

    Wolfhound: The Wolfhound is amazing in every category that matters - an ISP that's 20% higher than any other LFO engine, great TWR, unlocks relatively early, and is the cheapest cost/kn for an LFO engine.  Sorry rocketeers - the Wolfhound needed adjustment to have some valid trade-offs vs other vacuum engines.  It's still an amazingly efficient LFO engine, without having the sort of abysmal thrust & cost of a NERV, but now it doesn't completely overshadow every other LFO vacuum engine.  As a more specialized, high efficiency engine, its moved back in the tech tree with the other Making History Apollo-class parts as well.

    Cheetah: The cheetah, conversely, is too expensive and heavy to justify its relatively low TWR, low-end ISP and high cost, so several improvements were made to help it stand out.  Now it’s a bit like a smaller Wolfhound.

     

    Small & Maneuver Engine Tuning
    Finally we've got the small engines - for Making History, this is the Cub.

    Engine Comparison Thrust (Vac) ISP Vac ISP ASL Mass Vac TWR ASL TWR Cost Cost/kN Thrust Tech Level Gimbal EC/s Crash Tolerance Entry Cost
    Ant 2 315 80 0.02 10.19 2.59 110 55 Propulsion Systems (5) 0 0 7 1500
    Spider 2 290 260 0.02 10.19 9.14 120 60 Precision Propulsion (6) 10 0 7 1750
    Twitch 16 290 250 0.09 18.12 15.62 400 25 Precision Propulsion (6) 8 0 7 1600
    Puff 20 250 120 0.09 22.65 10.87 150 7.5 Precision Propulsion (6) 6 0 7 2500
    Spark 20 320 270 0.1 20.39 17.2 240 12 Propulsion Systems (5) 3 0 7 2800
    Current Cub 40 320 270 0.18 22.65 19.11 1000 25 Heavier Rocketry (6) 22.5 0 6 3000
    New Cub 32 310 280 0.18 18.12 16.37 800 25 Precision Propulsion (6) 22.5 0 7 3200

    Cub: The Cub, relative to other maneuver engines, is too good in too many areas.  Its ISP as good or better than all others, great TWR, fantastic (though only 1-axis) gimbal range and it is surface attachable, something most engines pay a penalty.  Therefore, it got a bit of an thrust and efficiency nerf - it actually generated far too much thrust relative to its companion, the Kodiak, which helps make its TWR more reasonable as well. Finally, it moved to the appropriate tech node for maneuvering engines.

    Other Making History Tweaks
    We've also made the engine plates fall into tech nodes appropriate for their size, rather all in the same node.

    Anyway, I hope you'll appreciate these changes - we'll be watching community reaction to see how they go over!  We encourage you to comment on these changes.
     

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    Fraston

    Oh my god the devblogs haven’t died!

    ”small changes” *almost doubles the entry and general cost of the wolfhound and gives it only a little more than 2/3rds TWR*

    Hey, I’m not complaining, I really disliked how OP the wolfhound was.

    Edited by Fraston
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    swjr-swis

    The last column of 'New Kodiak' seems to contradict itself: it is coloured green as if it's an improvement compared to 'Current Kodiak', but its entry cost is more expensive.

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    basic.syntax

    Thanks so much for writing up a rationale for the changes - please don't stop :)   

    I'd like to ask generally, why does high crash tolerance exist for larger engines.

    I regularly omit landing legs on larger designs with 20m/s crash tolerant engines, and that seems wrong. Engine bells should not support the weight of a rocket ;)

    I would like to see a proportional rebalance of all crash tolerances, to a scale of 1 - 10 m/s maximum.

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    Maxsimal
    56 minutes ago, Fraston said:

    Oh my god the devblogs haven’t died!

    ”small changes” *almost doubles the entry and general cost of the wolfhound and gives it only a little more than 2/3rds TWR*

    Hey, I’m not complaining, I really disliked how OP the wolfhound was.

    Mostly small changes.  Mastodon costs went down by a factor of 3x as well.  But yeah - Woflhound, Mastodon & Kodiak were the reason these changes were a priority.   Glad you're happy to see the blogs back.

     

    14 minutes ago, swjr-swis said:

    The last column of 'New Kodiak' seems to contradict itself: it is coloured green as if it's an improvement compared to 'Current Kodiak', but its entry cost is more expensive.

    Had some issues with formatting copying this over, there were a couple of other highlight errors - should be all fixed now, thanks!  Thanks you and &  @Snark for spotting them

    Edited by Maxsimal
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    swjr-swis
    11 minutes ago, basic.syntax said:

    I'd like to ask generally, why does high crash tolerance exist for larger engines.

    Wouldn't mind seeing this corrected as you mention... but only after we get landing legs that work like they're not composed entirely out of nitroglycerine, and a few sets of legs large enough to use safely with the larger engines and cross-sections.

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    basic.syntax
    1 minute ago, swjr-swis said:

    Wouldn't mind seeing this corrected as you mention... but only after we get landing legs that work like they're not composed entirely out of nitroglycerine, and a few sets of legs large enough to use safely with the larger engines and cross-sections.

    While I'd also like to see some larger legs, I'm not sure that is something Squad should focus on, given how far into fantasy land we go, with super heavy designs. Thus far, Squad has left sci-fi stuff up to the modders, but I don't count out the possibility they'd 'go there' in a future expansion (pun?). Multiple MPL's can generate tons and tons of science points in career mode, we need more toys to spend it on.

    Stock parts have no reasonable-looking answer imo, for a "lander" which uses the Mammoth, probably because the idea is real-life ridiculous. But to lift off EVE with an MPL, For Science!,  or to fulfill nutty ore transport contracts, you need to carefully transport and land something massive. 

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    Jestersage

    What is weird with the new Wolfhound is that it actually have worse actual efficency when compared to Poodle according to KER. With a direct swap on various Apollo-type clone, there is an actual loss of delta 20m/s to even 200m/s. However, it's TWR (when compared to Poodle) is better, but for a vacuum engine it's not much of an issue...

    Have not test out the cub yet, will check later. However, I think more and mroe of us are using Cubs more as a clone for SuperDraco on a Dragon V2, which is powerful and small

    Edited by Jestersage
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    Maxsimal
    30 minutes ago, swjr-swis said:

    Wouldn't mind seeing this corrected as you mention... but only after we get landing legs that work like they're not composed entirely out of nitroglycerine, and a few sets of legs large enough to use safely with the larger engines and cross-sections.

    Yeah - crash tolerances are crazy vs real world equivalents - which, let's face it, you couldn't ever set down on an engine bell and expect to use that engine for anything in the future - just check out the damage pictures of the Falcon 9's recent 'soft' water landing.  So in this case it's more of 'staying true to base game tuning' rather than reality.   And I don't see that changing even with bigger lander legs.  There are some great mods out there though if you like realism though... (and even they allow for higher-than-real crash tolerances)

    3 minutes ago, Jestersage said:

    What is weird with the new Wolfhound is that it actually have worse actual efficency when compared to Poodle according to KER. With a direct swap on various Apollo-type clone, there is an actual loss of delta 20m/s to even 200m/s. However, it's TWR (when compared to Poodle) is better, but for a vacuum engine it's not much of an issue...

    Have not test out the cub yet, will check later.

    MH Acapello, while looking like a Saturn V, doesn't really have a lot of the same mass ratios.  I mean, first it's basically an SSTO given Kerbin's low LKO orbit requirements.  So the 2nd stage becomes the trans-munar injection and Munar orbit stage... etc.   While it is a concern, it is definitely the case that the Poodle should be used if you don't have a lot of fuel mass to push with your dry mass, and the Wolfhound should be used if you want a more efficient stage with a longer burn time.   See!  Tradeoffs!   That's a good thing.

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    Snark
    12 minutes ago, Jestersage said:

    What is weird with the new Wolfhound is that it actually have worse actual efficency when compared to Poodle

    That's not possible to say as a general statement.  It completely depends on the context, i.e. what ship design operating in what type of physical situation.

    You might as well ask "which is more efficient, a Spark or a NERV?"  Answer:  the NERV is, for really big ships.  And the Spark is, for really little ones.

    The Wolfhound used to be way overpowered-- I basically never used the Poodle again, once the Wolfhound became available.  Now, though, it's an actually interesting set of tradeoffs-- depending on the ship design, mass, and intended mission, a Wolfhound will be better for some situations, whereas the Poodle would be for others.  So, IMO the rebalance is an improvement, simply because now I have a reason to use the Poodle sometimes, and also because it requires me to think about design (which is the sort of thing I like in KSP).

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    Jestersage
    8 minutes ago, Maxsimal said:

    MH Acapello, while looking like a Saturn V, doesn't really have a lot of the same mass ratios.  I mean, first it's basically an SSTO given Kerbin's low LKO orbit requirements.  So the 2nd stage becomes the trans-munar injection and Munar orbit stage... etc.   While it is a concern, it is definitely the case that the Poodle should be used if you don't have a lot of fuel mass to push with your dry mass, and the Wolfhound should be used if you want a more efficient stage with a longer burn time.   See!  Tradeoffs!   That's a good thing.

    I am refering to my own Apollo clones, ranging from one's made out of the Apollo Service Module, to the simple one where it's just a Mk1-3 capsule on top of a X16 fuel tank and then attach engine at the bottom, and even one that have the 2.5m Payload Bay on a x8 fuel tank -- but sure let's go with Acapello, which is a bit overkilled (and close to an x16 fueltank).

    Will be interested to see how other users does it; especially those that use it as a space-tug/upper stage engine.

    Speaking of which -- fix of Apollo Service Module door when? Right now if it's loaded, the door act as if closed.

    Edited by Jestersage
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    basic.syntax
    13 minutes ago, Maxsimal said:

    Yeah - crash tolerances are crazy vs real world equivalents - which, let's face it, you couldn't ever set down on an engine bell and expect to use that engine for anything in the future - just check out the damage pictures of the Falcon 9's recent 'soft' water landing.  So in this case it's more of 'staying true to base game tuning' rather than reality. 

    But... will you consider re-tuning crash tolerances? I'd be much more likely to engineer a landing protection assembly for Mammoth powered "landers" if the new range was up to a more risky 10 m/s maximum. The VAB is half of the game ;)  Right now its so easy to just "wing it" with landing on the heavy engines. (Which in a way, I suppose is "very Kerbal.") 

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    Foxster

    Let's be a tad more honest here...

    The MH engines were made OP to sell the expansion. Now no one is buying KSP for the expansion, they have been made more realistic. 

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    Deddly
    7 minutes ago, Foxster said:

    Let's be a tad more honest here...

    The MH engines were made OP to sell the expansion. Now no one is buying KSP for the expansion, they have been made more realistic. 

    I hardly think anyone would pay money just to get an OP engine. Config edits are free, innit.

     

    Anyway, these changes are very welcome. I'm not in favour of nerfing for the sake of things, but this is very well thought out and nicely presented, too. I'd actually like to see the NERVA in some way nerfed (nerved?). The stats should stay, but there could be some consequences to reputation if it us used in the atmosphere or crashes back to Kerbin, or maybe a Kerbal's health should suffer if they stand too close etc.

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    Maxsimal
    36 minutes ago, Foxster said:

    Let's be a tad more honest here...

    The MH engines were made OP to sell the expansion. Now no one is buying KSP for the expansion, they have been made more realistic. 

    If that was actually the case, wouldn't we have made all of them better than base-game engines?

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    Mr. Peabody
    59 minutes ago, Maxsimal said:

    If that was actually the case, wouldn't we have made all of them better than base-game engines?

    They were better than base game engines. In any case I'm glad to see them nerfed. Keep up the good work! :)

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    wasml

    Have found I was always using a subset of available engines and never touching others - this will make designing things more interesting - Good job! And thanks for the write-up - I always find the "behind the scenes" interesting.

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    Jestersage
    2 hours ago, Deddly said:

    I hardly think anyone would pay money just to get an OP engine. Config edits are free, innit.

    I would. Granted. If they really want to, they can do what Payday 2 did, and quite a lot of Take Two properties did: No base game, No DLC, only the combination verison available, and if Steam is smart can subtract properly.

    Selling OP stuff by cash is what allow Chinese game industry to expand, so...

    Edited by Jestersage
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    0111narwhalz
    10 hours ago, swjr-swis said:

    The last column of 'New Kodiak' seems to contradict itself: it is coloured green as if it's an improvement compared to 'Current Kodiak', but its entry cost is more expensive.

    There're colors?

    If there are, indeed, colors in the highlights, could you guys make them just a bit more saturated? I can't tell if they look colored because they are, or because my white balance is off.

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    Wallygator
    On 12/21/2018 at 4:26 PM, Fraston said:

    Oh my god the devblogs haven’t died!

    ”small changes” *almost doubles the entry and general cost of the wolfhound and gives it only a little more than 2/3rds TWR*

    Hey, I’m not complaining, I really disliked how OP the wolfhound was.

    yep.  I was just about to get the paddles out.

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    Jestersage

    Personally, what I really dislike is the nerf on the Cub, since my Dragon depends on it. On the other hand, I feel the Thud maybe reworked soon, so I will poodle at that time.

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    Whirligig Girl

    I've said it before, and I'll say it again.

    The Wolfhound and the Skiff are not balanced properly. The wolfhound represents the Apollo SPS, an AJ-10 variant. It should have a specific impulse around 310 s in vacuum, certainly no higher than 360 s. Even more, its thrust should be around 150 kN. The Wolfhound, unlike almost every other part, is at full scale compared to its original version, so 150 kN is actually enough for it. (The rest of the engines are about half scale). The Skiff meanwhile is a J-2 analogue that (when clustered five-fold) can't even lift the S-II stage with payload fully fueled. If any engine should fulfill the role of heavy, high-isp vacuum engine, it needs to be the Skiff.

    So yeah, the nerf to the Wolfhound is a step in the right direction, but it just isn't enough. It's still an absurdly powerful engine for what it is meant to represent, and in an historical parts pack I think that really matters.

     

    EDIT: Despite appearances, the Skiff is NOT an asl engine, it's based on the vacuum-optimized J-2 engine from the upper stages of the Saturn V.

    Edited by GregroxMun
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    Aegolius13
    4 hours ago, GregroxMun said:

    I've said it before, and I'll say it again.

    The Wolfhound and the Skiff are not balanced properly. The wolfhound represents the Apollo SPS, an AJ-10 variant. It should have a specific impulse around 310 s in vacuum, certainly no higher than 360 s. Even more, its thrust should be around 150 kN. The Wolfhound, unlike almost every other part, is at full scale compared to its original version, so 150 kN is actually enough for it. (The rest of the engines are about half scale). The Skiff meanwhile is a J-2 analogue that (when clustered five-fold) can't even lift the S-II stage with payload fully fueled. If any engine should fulfill the role of heavy, high-isp vacuum engine, it needs to be the Skiff.

    So yeah, the nerf to the Wolfhound is a step in the right direction, but it just isn't enough. It's still an absurdly powerful engine for what it is meant to represent, and in an historical parts pack I think that really matters.

     

    EDIT: Despite appearances, the Skiff is NOT an asl engine, it's based on the vacuum-optimized J-2 engine from the upper stages of the Saturn V.

    I think I said this before in one of the "Wolfhound / Skiff Switched" threads, but there's just no way to be completely faithful to the historical stats, and still balanced for gameplay.  As you say, the Apollo SPS engine was relatively low ISP due to hypergolic fuel and so forth, but thay was based on the need to store fuel in space and easily restart. The J-2 had much better efficiency, but that came with all the disadvantages of hydrogen (low fuel density, poor storage) etc.  

    But since stock KSP does has only one kind of LFO and does not simulate fuel boil-off or part failures, none of those real-world distinctions would come through in the game.  A faithful analog of a pressure-fed hypergolic engine would just be terrible compared to stuff like the Skiff, because the game models its disadvantages but not its advantages.  (Kind of the same reason the Puff is virtually useless).  To make make an engine worth using in an Apollo SPS-type role, they needed to to give it good stats for that mission, within the constraints of the game.  Which basically means a good vacuum ISP. 

    However, I am with you that the Wolfhound does have more mass and thrust than makes sense.  The Cheetah probably fits better as an SPS analog if you're planning to use a Terrier / Spark lander.  Maybe they amped up the Wolfhound because the small vacuum engine design space was getting too crowded, but it does seem like a head-scratcher.

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