Is KSP in need of a "balance patch" again?

[MauricioMF]

The engines needs a great reestruturation... there's a lot of redundant and unusable engines... players only use a pool of 3 or 4 engines for all buildings...

[Tweeker]

I agree It is obviously supposed to be the AJ10 from the Apollo SPM. But regardless of which AJ10 engine it is, the engine is OP. In terms of ISP it is has about 30% more than it need, but in thrust it is ridiculously OP. Incredibly OP.  Worse than even the vector or mammoth.

It needs to have a thrust of about 20KN if it is supposed to be an analogue of the  AJ10-137.  375KN is just stoopid, that's nearly 20 times what it should be. If the Mastodon were similarly scaled it would have 30,000KN of thrust.

This thing doesn't need a nerfbat it needs a nerfnuke.

 

 

 

[General Apocalypse]

13 hours ago, Shadowmage said:

I believe that you may be misinterpreting some of the information.

There are many different AJ-10 engines.  The one you link to is the AJ10-118K; used on the second stage of the Delta-II.  This one is not present in stock KSP as far as I am aware, at least not in any sort of 'replica' fashion.

The one used on the Apollo-SM (and that the stock/MH Wolfhound is based on) is the AJ10-137 -
There is also the AJ10-190 that was used as the Space-Shuttle OMS engines (The stock 'Puff' engine I believe... though I rarely use stock parts, so could have a different name...):

 

That research does look better , there are a lot of visual similarities. That is still a 300 kg engine producing 88 kN with and ISP of 315 . It's nothing like the 2.5 ton engine so with over 8 times the weight and 4 times the thrust.

http://www.dtic.mil/dtic/tr/fulltext/u2/850062.pdf

http://www.alternatewars.com/BBOW/Space/SP-8120_Excerpt.pdf

 

Right now the Wolfhound has basically received the some of the stats of the IRL RS-25 while having a distinct look. The engine is terrible except for upper stage LKO missions where it is quite a good engine. To call it OP is simply not true , the thing has two good stats going for him. It's ISP and it's name.

[AVaughan]

1 hour ago, General Apocalypse said:

while having a distinct look

Actually I think it looks exactly like an Apollo service module engine.

[Tweeker]

 

Quote

Right now the Wolfhound has basically received the some of the stats of the IRL RS-25 while having a distinct look. The engine is terrible except for upper stage LKO missions where it is quite a good engine. To call it OP is simply not true , the thing has two good stats going for him. It's ISP and it's name.

 The thing is it is not an RS-25, and there is no reason to make it one.  The SPS engine has about 1/20th the thrust of a RS-25. It was an orbital engine, used only for transfer burns. It does not need to have anywhere near the thrust it has been given. 

IRL the AJ10 engine in the SM had about 1/10th the thrust of the J2 in the S-IVB,  here it has 1.25 TIMES  more thrust. When building an Apollo replica it makes the  Skiff redundant.  ----no, not just redundant it make a mockery of it.  for a 12% increase in cost you get 25% more thrust and  25% better ISP.  With the Wolfhound as is why is there any reason to ever use the Skiff?

   

[winged]

I posted this on reddit two years ago:

 

LV-909 in real life would cost few million USD (let's assume 4,5 mln) - This makes our ladder  one of the most expensive things available in game with a price of about 1 000 000 USD per kg.

Gold for a comparison costs only about 40 000 USD per kg.

 

Can you imagine what material this ladder is made of? Emerald? Aquamarine?

 

Edited June 6, 2018 by winged

[Tweeker]

It's not that far out of line after all,

http://articles.latimes.com/1986-07-30/news/vw-18804_1_nut

 

In 1985 dollars:

Other items offered in the catalogue include a $285 screwdriver, a $7,622 coffee maker, a $387 flat washer, a $469 wrench, a $214 flashlight, a $437 tape measure, a $2,228 monkey wrench, a $748 pair of duckbill pliers, a $74,165 aluminum ladder, a $659 ashtray and a $240- million airplane.

Edited June 7, 2018 by Tweeker

[Tweeker]

Among the engine that have a real world counterpart it is fairly simple, and unambiguous to determine what the stats should be, 

Kickback	2430	▲ +360%
Twin Boar	3500	▲ +75%
NERV	75	▲ +25%
Mastodon	1600	▲ +19%
Bobcat	430	▲  +7%
Kodiak	220	▼  -9%
Cheetah	100	▼  -20%
Skiff	230	▼  -23%
Mammoth	1700	▼  -57.5%
Vector	425	▼  -57.5%
Puff	6	▼  -70%
Rhino	395	▼  -85.25%
Wolfhound	22	▼  -95%

 

 

[Tyko]

7 hours ago, Tweeker said:

Among the engine that have a real world counterpart it is fairly simple, and unambiguous to determine what the stats should be, 

Kickback	2430	▲ +360%
Twin Boar	3500	▲ +75%
NERV	75	▲ +25%
Mastodon	1600	▲ +19%
Bobcat	430	▲  +7%
Kodiak	220	▼  -9%
Cheetah	100	▼  -20%
Skiff	230	▼  -23%
Mammoth	1700	▼  -57.5%
Vector	425	▼  -57.5%
Puff	6	▼  -70%
Rhino	395	▼  -85.25%
Wolfhound	22	▼  -95%

 

 

what are the stats in the two columns? there aren't any column titles  

[Tweeker]

Sorry about that,

Engine

Corrected thrust

Relative change

Kickback	2430	▲ +360%
Twin Boar	3500	▲ +75%
NERV	75	▲ +25%
Mastodon	1600	▲ +19%
Bobcat	430	▲  +7%
Kodiak	220	▼  -9%
Cheetah	100	▼  -20%
Skiff	230	▼  -23%
Mammoth	1700	▼  -57.5%
Vector	425	▼  -57.5%
Puff	6	▼  -70%
Rhino	295	▼  -85.25%
Wolfhound	22	▼  -95%

 

Edited June 9, 2018 by Tweeker
Typo

[TheRedTom]

2 hours ago, Tweeker said:

Sorry about that,

~Snip~  

 

How did you calculate that corrected thrust?

[Tweeker]

47 minutes ago, TheRedTom said:

How did you calculate that corrected thrust?

 A while back, I was on about how the vector was OP, and the Kickback was underpowered.

Their thrust relative to each other is all wrong.  it should be about 6:1 favoring the  kickback,  ~2,400,000 lbf for the SRBs.  VS. ~412,000 lbf  for the rs-25

In KSP it is  about  0.6:1,  675 for the kickback  VS 1000 for the Vector.

I did some messing the values thrust of the kickback and vector to get  a more realistic balance, 

rebalanced shuttle

This is just an extension of that.

 

[KerikBalm]

On 5/12/2018 at 2:06 PM, KerikBalm said:

The SSME had a prettz damn good vacuum Isp (452 s), better than the J-2 (421 s)on the Saturn V 2nd and 3rd stages. Its actually quite an advanced design

...

Only a few LH/LOx engines beat the SSMEs for their vacuum thrust

...

The Vector, as I mentioned, also has a poor vacuum Isp relative to the other engines to be a proper SSME analogue... but its TWR is one of the best in the game, and as I mentioned even with 8x kickbacks, a vector trio is going to supply over double the % of total thrust at launch as the real SSMEs on the STS... so thats one reason I'm not suggesting they get ~330-340 Isp... that and shuttles are novelties in KSP, you'd never arrive at a shuttle design by trying to optimize for some parameters in game... so I'm perfectly fine with its balance and gameplay purpose as a powerful atmospheric booster engine (its great for Eve ascents because of its awesome thrust:cross section ratio)

Also, both the 3.75m Rhino and the 1.875/2.5m Skiff are based on variants of the J-2, so I don't see how the Rhino and Skiff in your chart don't have the same stats. Its also why I wouldn't compare a 1.25m diameter kickback SRB to the SRBs of the space shuttle (although a cluster of 4 on each side is more comparable).

Here's my Rebalance proposal:

Spoiler

@PART[LiquidEngineKE-1]
    { 
        @mass = 5.25
        @MODULE[ModuleEngines]
        { 
            @maxThrust = 1450
            !atmosphereCurve
            atmosphereCurve
            {
                key = 0 305
                key = 1 295
                key = 15 0.001
            }
        }
    }// for a 5 meter 5x cluster, has the same thrust/cross section as a mammoth, slightly better TWR for worth vacumm performance
@PART[LiquidEngineLV-T91]
    { 
        @mass = 1.15
        @MODULE[ModuleEngines]
        { 
            @maxThrust = 145
        }
    }// gave it a bit more oomph, still a bit redundant with an aerospike that  provides more thrust for the same mass and only 5 less Isp
@PART[LiquidEngineLV-TX87]
    { 
        @mass = 3
        @MODULE[ModuleEngines]
        { 
            @maxThrust = 660
        }
    } // Increased its thrust overcross section area by 50% (it was really bad) and its TWR by 10%, its still far worse than the mainsail in TWR and Isp at any level
@PART[LiquidEngineRE-I2]
    { 
        @mass = 2.5
        @MODULE[ModuleEngines]
        { 
            @maxThrust = 625
        }
    } // Increased mass more than thrust, no longer the highest TWR liquid fuel engine in the game
@PART[LiquidEngineRE-J10]
    { 
        @mass = 2
        @MODULE[ModuleEngines]
        { 
        @maxThrust = 275
            !atmosphereCurve
            atmosphereCurve
            {
                key = 0 355
                key = 1 70
                key = 6 0.001
            }
        }
    }// Nerfed Isp, TWR and thrust, still better than the poodle
@PART[LiquidEngineRK-7]
    { 
        @mass = 2.5
        @MODULE[ModuleEngines]
        { 
        @maxThrust = 500
            !atmosphereCurve
            atmosphereCurve
            {
                key = 0 305
                key = 1 275
                key = 15 0.001
            }
        }
    }// since its also a 1.875m engine, I figured it could use a thrust and mass increase, also since its a larger /later tech engine, I improved its atmospheric Isp, its now distinct from the Reliant
@PART[engineLargeSkipper]
    { 
        @mass = 3.5
        @MODULE[ModuleEngines]
        { 
            @maxThrust = 775
            !atmosphereCurve
            atmosphereCurve
            {
                key = 0 325
                key = 1 270
                key = 12 0.001
            }
        }// small mass and thrust increase. Nerfed Atmo Isp by 10 and increased vacuum Isp by 5 to make it suit a role of a 2nd stage engine better
    }
@PART[RAPIER]
    {
        @MODULE[ModuleEnginesFX],1
        { 
            !atmosphereCurve
            atmosphereCurve
            {
                key = 0 330
                key = 1 265
                key = 9 0.001
            }
        }// gave it the Isp curve of the skiff
    }
    }

Then there's the thing with engines all using the same fuel type and being infinitely restartable with no special precautions... which would also make it unbalanced to just directly base their stats off of real world Isp/Thrust/TWR

[Tweeker]

 

4 hours ago, KerikBalm said:

Also, both the 3.75m Rhino and the 1.875/2.5m Skiff are based on variants of the J-2, so I don't see how the Rhino and Skiff in your chart don't have the same stats. Its also why I wouldn't compare a 1.25m diameter kickback SRB to the SRBs of the space shuttle (although a cluster of 4 on each side is more comparable).

Here's my Rebalance proposal:

  Reveal hidden contents

@PART[LiquidEngineKE-1]
    { 
        @mass = 5.25
        @MODULE[ModuleEngines]
        { 
            @maxThrust = 1450
            !atmosphereCurve
            atmosphereCurve
            {
                key = 0 305
                key = 1 295
                key = 15 0.001
            }
        }
    }// for a 5 meter 5x cluster, has the same thrust/cross section as a mammoth, slightly better TWR for worth vacumm performance
@PART[LiquidEngineLV-T91]
    { 
        @mass = 1.15
        @MODULE[ModuleEngines]
        { 
            @maxThrust = 145
        }
    }// gave it a bit more oomph, still a bit redundant with an aerospike that  provides more thrust for the same mass and only 5 less Isp
@PART[LiquidEngineLV-TX87]
    { 
        @mass = 3
        @MODULE[ModuleEngines]
        { 
            @maxThrust = 660
        }
    } // Increased its thrust overcross section area by 50% (it was really bad) and its TWR by 10%, its still far worse than the mainsail in TWR and Isp at any level
@PART[LiquidEngineRE-I2]
    { 
        @mass = 2.5
        @MODULE[ModuleEngines]
        { 
            @maxThrust = 625
        }
    } // Increased mass more than thrust, no longer the highest TWR liquid fuel engine in the game
@PART[LiquidEngineRE-J10]
    { 
        @mass = 2
        @MODULE[ModuleEngines]
        { 
        @maxThrust = 275
            !atmosphereCurve
            atmosphereCurve
            {
                key = 0 355
                key = 1 70
                key = 6 0.001
            }
        }
    }// Nerfed Isp, TWR and thrust, still better than the poodle
@PART[LiquidEngineRK-7]
    { 
        @mass = 2.5
        @MODULE[ModuleEngines]
        { 
        @maxThrust = 500
            !atmosphereCurve
            atmosphereCurve
            {
                key = 0 305
                key = 1 275
                key = 15 0.001
            }
        }
    }// since its also a 1.875m engine, I figured it could use a thrust and mass increase, also since its a larger /later tech engine, I improved its atmospheric Isp, its now distinct from the Reliant
@PART[engineLargeSkipper]
    { 
        @mass = 3.5
        @MODULE[ModuleEngines]
        { 
            @maxThrust = 775
            !atmosphereCurve
            atmosphereCurve
            {
                key = 0 325
                key = 1 270
                key = 12 0.001
            }
        }// small mass and thrust increase. Nerfed Atmo Isp by 10 and increased vacuum Isp by 5 to make it suit a role of a 2nd stage engine better
    }
@PART[RAPIER]
    {
        @MODULE[ModuleEnginesFX],1
        { 
            !atmosphereCurve
            atmosphereCurve
            {
                key = 0 330
                key = 1 265
                key = 9 0.001
            }
        }// gave it the Isp curve of the skiff
    }
    }

Then there's the thing with engines all using the same fuel type and being infinitely restartable with no special precautions... which would also make it unbalanced to just directly base their stats off of real world Isp/Thrust/TWR

 The J-2 (skiff) and the J-2X(rhino)  have more than 40 years of development between them so it makes sense that they would have different stats.

I really hate to give away my brainsweat for free, ideas area on of the few things that a person can truly call their own. But it's not doing me any good to sit on it so.....

 

      The assumption was always that, in KSP,  the mainsail was the equivalent of the  F-1,  the other KSP engines where a little more ambivalent.  With that in mind I developed the theory that you could convert real world thrust to KSP by taking real world thrust in LBf and diving by 1,000  so F-1 should equal  1,500 SL  and 1746 Vac, not an exact fit,  but close enough to be interesting. Some time passed, As I said above, after the vector was split off from the mammoth I was not please with this new engine. As I have pointed out they give SRBs the short end of the stick,  regardless whether they are burning LH or a denser fuel the have way too much thrust. I did some messing a round, as you can see in the thread above, and adjusted the Vector and Kickback to more realistic proportions. These also fell in the same range for real world thrust ÷ 1000. I ended up with 400 for the Vector VS 418,000-512,000 and 2400 for the kickback vs 2,800,000 - 1,800,000. I think the re-enforces the basic theory. Moving on to the making history engines,  some of them are quite close to this metric, the Bobcat and Kodiak in particular. Coming back to the Rhino and Skiff the reason they end up with such different thrust is because the J-2, and J-2X were quite far apart in this regard. And also I made a typo, it should be: 

Rhino

295

▼  -85.25%

 

    Coming to the issue of fuel type, KSP is already a 5 fuel game. and it offers  ISP for each fuel,  monoprop & Solid are low ISP fuels, Rocket fuel offers better ISP, followed by LFO/Nuclear and finally Xenon. Most of these are close to the real world equivalent.

I should say at this point that I don't have as firm of an opinion about ISP balance as I do about thrust, Thrust is fairly straight forward, ISP has a few wrinkles, It does make a certain amount of sense to simplify rocket fuel into one category, most of them have similar densities, so they can be can be generalized into a single fuel, the only real outlier here is Liquid Hydrogen, which is fluffier and gives a higher ISP. To balance LH engine in game you need to either add Liquid hydrogen, or an analogue, or down convert the LH engines to RP/UDMH/ETC. Not adding another fuel makes a certain kind of sense, in keeping thing simple, but it means you need to figure out a  conversion factor for  LH burning engines to  RP/UDMH burning engines.   ISP kind of does that, but it doesn't correct for volume of propellant, which is important  to consider. The vector is a prime example of the problems this conversion creates.  Does a 30% reduction in ISP warrant a 230% increase in thrust? This seems wrong to me. 

  

Edited June 9, 2018 by Tweeker

[Tweeker]

 

      After thinking about it a while, maybe it is time to add a LH/OYX equivalent fuel to the game. It wouldn't make things that much mor complicated, and  it would make balancing the engines easier, as you would have another factor to use. Instead of having yet another KER/LOX engine.

    Trying to build a ker-pollo, that looks right I find the rocket to be way high in total Delta/v and low in thrust, too low to lift off using 5 Mastodons. Defueling the S-II and S-IVB to about 30% results in a more  realistic rocket. Incidentally this puts them at a similar density to LH/OYX. {I Think, maybe I'm wrong}.

      The only other thing I'd mention is that SRB's are still seriously getting the short end of the stick. You can build a Soyuz, Gemini, Mercury, Etc,   But you can't realy build a good replica of anything that relies on solid rockets, no Ariane, no  Delta, no Atlas, No Epsilon.

 

 

[KerikBalm]

I would be open to adding lH2 as a fuel type, and one that needs cooling via radiators, or it will be lost over time (perhaps using something like a reverse ISRU calculation in the background to subtract a fuel type rather than add it)...

but that would be beyond the scope of a balance pass, and would have to come as part of a fairly significant update

[Tyko]

On 7/1/2018 at 7:26 AM, KerikBalm said:

I would be open to adding lH2 as a fuel type, and one that needs cooling via radiators, or it will be lost over time (perhaps using something like a reverse ISRU calculation in the background to subtract a fuel type rather than add it)...

but that would be beyond the scope of a balance pass, and would have to come as part of a fairly significant update

I've thought about that too...the problem is that KSP stock is already easy enough with current LFO engine ISPs in the 275-350 range. Adding in a set of higher efficiency engines would make the game ridiculously easy.

I'd love to see a DLC that was "advanced play" with a scaled up system (maybe 2.5, 3.2 and 5x options) along with LH2 engines, converting nuclear engines to LH2 and adding a few more nuclear engines. This would be something I'd really love. Currently scaling the system takes at least 4 mods, all of which have to be updated and working together well.

 

[KerikBalm]

I can confirm that engines in KSP are already good enough to play well in a 3x rescaled system