[WIP] Nert's Dev Thread - Current: various updates

[WarriorSabe]

8 minutes ago, KSPrynk said:

Yeah, it's just hard for me to suspend disbelief and think anyone would feed RP-1 into an NTR.  That's practically rollin' coal....

Just don't use that patch then; it's like the hall effect xenon patch - just for those who don't want extra resources

[Spaceman.Spiff]

21 minutes ago, KSPrynk said:

Of the two, SystemHeat is the one I wonder about most, because mass flow rates change (I think - I scaled up thrust to inversely correspond with the drop in Isp, so it may cancel out), and I don't know if the reactor cares or the working assumption is that it's chugging out a fixed amount of waste heat kilowatts for a given power setting, regardless of propellant or how much is passing through

ATM systemheat doesn’t do exhaust cooling at all so it’s inconsequential 

[lemon cup]

15 hours ago, Nertea said:

They're in the development branch now if you're brave...

My Courage stat is average, but my Stupidity is maxed out, so needless to say I’m in...!

Firstly just gotta say, the plumes are fantastic. I did not imagine effects like this when you first released Waterfall, now I’m seeing the true potential and it rocks.

On that note, did you make tweaks to the Hydrolox plumes in the recent dev release? My memory might be off but they look even better to me now.

Lastly I haven’t had much time to do balance testing but I did load up a mid-early career and take a look at the community tech tree. I would recommend making the Methalox engines a little less accessible, consider shifting some of them to the right by one node. Like the BE-4 Vacuum  and the Raptor-9 SL Cluster, for instance, should probably be moved up to Experimental Rocketry.

 

[Erik3003]

23 hours ago, Nertea said:

They're in the development branch now if you're brave, though you'll have to go get all the updated dependencies and waterfall dev yourself. 

Gotta say, the engines look really beautiful ingame. Though they may need a little more balancing imo. The Deinonychus, while trust is already high compared to other 1.25m engines, does still loose quite substantially against the Vector when it comes to clustering. The Vector seems like an unfair comparison, since it is fairly high up the tech tree, but it is also 1.25m and doesn't suffer the same problems as methane engines (boiloff, less density). The Iguanodon however competes much better against the Vector, offering slightly higher thrust and ISP, while keeping a very similar albeit slightly larger profile when in compact mode, making it the new king of clustering. The Allosaur seems especially underpowered to me, being just a bigger and slightly more efficient Mailsaw.

I think the best way to try to balance them is to look at the TWR of the engines:
The Vector has a TWR of ~234 kN/T (ATM), making it the close second best TWR in the vanilla game (Mammoth being the best, which are 4 Vectors missing a ton). The Deinonychus has a TWR of ~256 kN/T, the Iguanodon has ~320 kN/T and the Allosaur has ~231 kN/T. There is an argument to be made that methane engines should have higher TWR, since they also need more fuel tanks to accommodate the lower fuel density and sometimes extra electrical systems to cover the boiloff. The bigger, less clusterable engines should also generally have a slightly higher TWR, to keep clustering from potentially being always superior.

Personally, I would therefore give the Deinonychus more thrust, ~500 kN ASL, increasing the TWR of it to ~312 kN/T. The Iguanodon should get a slight mass increase to 3.1 T, lowering the TWR to 310 kN/T ASL. Since the Deinonychus has a slightly higher ISP than the the Iguanodon while at equal TWR, the Deinonychus is now generally slightly more preferable, but the Iguanodon still has the edge when it comes to size vs thrust, making it still more viable on bigger rockets. The Allosaur is quite huge, although in the 2.5m class, its scale is a lot more comparable to (non-cluster) engines of the 3.75m class than a Mailsaw, so it should probably get a big trust upgrade like 2200 kN ASL and a slight weight increase to 7 T, giving it a record TWR of 314 kN/T. This thrust upgrade also makes sense to bring it more in line with the other methane engines, which have generally much higher thrust compared to other engines of their size class.

I'd also change the tech progression in the vein of what lemon cup said, though I'd even go a step further: Methane vacuum and hydrogen lifter engines get shifted one node to the right compared to LF engines, while methane lifter and hydrogen vacuum engines get shifted a whole two nodes. This kinda makes the CTT a soft requirement, but I image most people using CryoEngines using it anyway.

[Starhelperdude]

4 hours ago, Erik3003 said:

Gotta say, the engines look really beautiful ingame. Though they may need a little more balancing imo. The Deinonychus, while trust is already high compared to other 1.25m engines, does still loose quite substantially against the Vector when it comes to clustering. The Vector seems like an unfair comparison, since it is fairly high up the tech tree, but it is also 1.25m and doesn't suffer the same problems as methane engines (boiloff, less density). The Iguanodon however competes much better against the Vector, offering slightly higher thrust and ISP, while keeping a very similar albeit slightly larger profile when in compact mode, making it the new king of clustering. The Allosaur seems especially underpowered to me, being just a bigger and slightly more efficient Mailsaw.

I think the best way to try to balance them is to look at the TWR of the engines:
The Vector has a TWR of ~234 kN/T (ATM), making it the close second best TWR in the vanilla game (Mammoth being the best, which are 4 Vectors missing a ton). The Deinonychus has a TWR of ~256 kN/T, the Iguanodon has ~320 kN/T and the Allosaur has ~231 kN/T. There is an argument to be made that methane engines should have higher TWR, since they also need more fuel tanks to accommodate the lower fuel density and sometimes extra electrical systems to cover the boiloff. The bigger, less clusterable engines should also generally have a slightly higher TWR, to keep clustering from potentially being always superior.

 

I suggest you make a version of your balance with the cryoengines Restock/+ patch enabled, so for example here the vector now has lower thrust, higher isp (though lower than the RD-0120 but higher thrust) and uses LH2

 

[Nertea]

11 hours ago, lemon cup said:

My Courage stat is average, but my Stupidity is maxed out, so needless to say I’m in...!

Firstly just gotta say, the plumes are fantastic. I did not imagine effects like this when you first released Waterfall, now I’m seeing the true potential and it rocks.

On that note, did you make tweaks to the Hydrolox plumes in the recent dev release? My memory might be off but they look even better to me now.

Lastly I haven’t had much time to do balance testing but I did load up a mid-early career and take a look at the community tech tree. I would recommend making the Methalox engines a little less accessible, consider shifting some of them to the right by one node. Like the BE-4 Vacuum  and the Raptor-9 SL Cluster, for instance, should probably be moved up to Experimental Rocketry.

Well, plumes are at this point all @Zorg, he has contributed significantly to the base Waterfall templates, including all these ML ones and updates to the hydrolox ones. 

@Erik3003, thanks for the analysis, I have some clarification/disagreement on a few points, as below:

2 hours ago, Erik3003 said:

I think the best way to try to balance them is to look at the TWR of the engines:

It's really important to note the specific impulse too. If you only balance on TWR you negate the fact that a number of these engines have 20-30s better impulse than their LF counterparts. 

2 hours ago, Erik3003 said:

The Vector has a TWR of ~234 kN/T (ATM), making it the close second best TWR in the vanilla game (Mammoth being the best, which are 4 Vectors missing a ton). The Deinonychus has a TWR of ~256 kN/T, the Iguanodon has ~320 kN/T and the Allosaur has ~231 kN/T.

Ok, that looks to me like the Iguanodon is out of line then! So far that it was probably some kinda typo.

2 hours ago, Erik3003 said:

There is an argument to be made that methane engines should have higher TWR, since they also need more fuel tanks to accommodate the lower fuel density and sometimes extra electrical systems to cover the boiloff. 

Ah ok see that I need to disagree with. Methalox mass ratio is currently set at 7.5, so very close to LF/O spaceplane tanks at 7.8 and not that much worse than LF/O rocket tanks at 9. Density and number of fuel tanks aren't relevant at this. I would also suggest that boiloff be ignored for launch engines which you seem to be aiming at here - on the scale of a launch, or even on the scale of a mission to the Mun/Minmus, boiloff is very small. 

2 hours ago, Erik3003 said:

Personally, I would therefore give the Deinonychus more thrust, ~500 kN ASL, increasing the TWR of it to ~312 kN/T. The Iguanodon should get a slight mass increase to 3.1 T, lowering the TWR to 310 kN/T ASL. Since the Deinonychus has a slightly higher ISP than the the Iguanodon while at equal TWR, the Deinonychus is now generally slightly more preferable, but the Iguanodon still has the edge when it comes to size vs thrust, making it still more viable on bigger rockets. The Allosaur is quite huge, although in the 2.5m class, its scale is a lot more comparable to (non-cluster) engines of the 3.75m class than a Mailsaw, so it should probably get a big trust upgrade like 2200 kN ASL and a slight weight increase to 7 T, giving it a record TWR of 314 kN/T. This thrust upgrade also makes sense to bring it more in line with the other methane engines, which have generally much higher thrust compared to other engines of their size class.

Yeah your point about clustering is well-made and should be stared at. However... the numbers you're proposing for TWR there are eyebrow-raising. I don't want to make these engines the absolute best, which they would be at those TWRs and with the current Isps. If that was the case they'd definitely need to be pushed out into the tech tree! They should be at a middle point between the LFO/LH2O things currently in existence, which trade TWR for Isp. 

I have played around ingame with the engines and I generally feel that the TWR isn't too low when building your average rocket. I think it's always problematic to compare things to certain stock engines that really fall outside of the game's typical performance envelope - the Vector and Wolfhound should both be treated quite carefully.

 

[Spaceman.Spiff]

5 hours ago, Erik3003 said:

The Vector seems like an unfair comparison, since it is fairly high up the tech tree, but it is also 1.25m and doesn't suffer the same problems as methane engines (boiloff, less density).

Maybe you’re using the LFO patch but the Vector is an LH2 burning engine. 

I think the balance was based on LH2 vs. methane, in which methane wins in both of the categories you described. 

[CDSlice]

Just now, Spaceman.Spiff said:

Maybe you’re using the LFO patch but the Vector is an LH2 burning engine. 

I think the balance was based on LH2 vs. methane, in which methane wins in both of the categories you described. 

Uh, the Vector is a stock engine that burns liquid fuel unless you use the optional CyroEngines patch that converts some stock engines into LH2 engines (and also makes the Rhino super OP so I don't use it)

[Spaceman.Spiff]

3 minutes ago, CDSlice said:

Uh, the Vector is a stock engine that burns liquid fuel unless you use the optional CyroEngines patch that converts some stock engines into LH2 engines (and also makes the Rhino super OP so I don't use it)

Oh. 
I’ve been using that patch for so long I forgot. 

[coyotesfrontier]

@Nertea, I made EngineLight configs for the new methalox engines:

https://pastebin.com/ADQjGKye

[Erik3003]

4 hours ago, Nertea said:

It's really important to note the specific impulse too. If you only balance on TWR you negate the fact that a number of these engines have 20-30s better impulse than their LF counterparts.

I didn't take ISP into account, because I was balancing the methane engines relative to each other, since they all have an almost equal ISP of roughly 330 seconds at sea level. That is just 12% more than the (stock) Vector, though that is a bad point of comparison, so lets look at more reasonable average LF/Ox engine ISP of 280, making it a good 18% more. Now lets look at LH2/Ox launcher engines for a point of comparison. The ISP at sea level is around 370 seconds here, which is roughly 32% more than LF/Ox, so quite significant.

4 hours ago, Nertea said:

Ah ok see that I need to disagree with. Methalox mass ratio is currently set at 7.5, so very close to LF/O spaceplane tanks at 7.8 and not that much worse than LF/O rocket tanks at 9. Density and number of fuel tanks aren't relevant at this. I would also suggest that boiloff be ignored for launch engines which you seem to be aiming at here - on the scale of a launch, or even on the scale of a mission to the Mun/Minmus, boiloff is very small.

Obviously, the fuel types aren't really directly comparable, because of differing densities and boiloff. But since boiloff isn't that significant for a launcher, we can take a look at comparing their densities. Looking at your figures and at the code, LCH4/Ox is ~83% as dense as LF/Ox, LH2/Ox is just ~0.45 as dense as LF/Ox. This means LH2/Ox requires ~124% more fuel tanks than LF/Ox and LCH4/Ox requires just 20% more for the same dV, in a theoretical perfect environment at equal ISP and infinite thrust that is. (This is ofc reliant on my logic, math and physics being right, as well as no stupid errors sneaking in, so no guarantees, I'm certainly not an expert at all on any of these things)

So, more fuel tanks mean more dry mass! Well, no, upon trying to calculate the densities with ingame weights, I stumbled upon some inconsistencies with the data in the code and upon further inspection I discovered: The dry mass of tanks change when the fuel type is different, so that the same weight of fuel is accompanied by the same dry tank mass for any fuel.

Well, this means the performance across different fuel types is actually quite comparable and that you are right and my balance has been build on false assumptions. The dV increase through higher ISP is actually "free", and not as I thought significantly reduced by the added dry mass, which makes the Iguanodon obviously a bad choice as a new balance baseline. The Vector in hindsight is also a terrible choice for a point of reference, since it is quite overpowered in the vanilla game and there is actually a patch to balance it into something else provided for CryoEngines.

So a better move would be to orient the balance around the Deinonychus, as it is a quite good engine which sets a theme of methane engines having very high thrust, excellent (but not ludicrous) TWR and good ISP. With the new TDW to aim for being ~250 kN/T, the Iguanodon could be nerfed to weigh 4 T (~240 kN/T TWR) and I'd still give the Allosaur a weight and thrust increase but to 2200 kN ASL and 9 T (~244 kN/T TWR). An argument could made to nerf them further, since they don't possess such huge drawbacks as hydrogen engines, but I think it would be better to try to regulate them trough means other than nerfing their performance, like cost or appearing late in the tech tree.

And now for something completely different:
The naming schemes for engines is a bit, well strange. Stock/Restock LF/Ox engines are "Liquid Fuel Engines", CryoEngines LH2/Ox engines are "Cryogenic Rocket Engines" and CryoEngines LCH4/Ox engines are "Liquid Rocket Engines". "Hydrogen Fuel Engines" and "Methane Fuel Engines" would be more consistent imo. Also, the CryoEngines Restock Patch changes the fuel type of some engines, but still leaves them named as "Liquid Fuel Engines". This may be an oversight, when not a limitation of MM Patches.

[Nertea]

Yep, that sounds about correct. I will look specifically at the Allosaur and Iguanodon.

3 hours ago, Erik3003 said:

Well, this means the performance across different fuel types is actually quite comparable and that you are right and my balance has been build on false assumptions. The dV increase through higher ISP is actually "free", and not as I thought significantly reduced by the added dry mass

One note here - this isn't true for the LH2/O engines, whose tanks do have a lower mass ratio (~5.5 iirc). So they do suffer from a decrease in performance. However this doesn't show up so much ingame because LH2 is so light. It's also a real 'real' issue with deep space LH2 architectures that I wanted to represent. 

3 hours ago, Erik3003 said:

The naming schemes for engines is a bit, well strange. Stock/Restock LF/Ox engines are "Liquid Fuel Engines", CryoEngines LH2/Ox engines are "Cryogenic Rocket Engines" and CryoEngines LCH4/Ox engines are "Liquid Rocket Engines". "Hydrogen Fuel Engines" and "Methane Fuel Engines" would be more consistent imo. Also, the CryoEngines Restock Patch changes the fuel type of some engines, but still leaves them named as "Liquid Fuel Engines". This may be an oversight, when not a limitation of MM Patches.

You're right there, bit inconsistent. I don't really like Hydrogen Fuel Engines/Methane Fuel Engines either though. Open to suggestions. 

[lemon cup]

8 hours ago, Nertea said:

Open to suggestions. 

In my opinion, you have successfully made the mod accessible and easy to understand to a wide audience. That being said I think the majority of people downloading CryoEngines are at least somewhat familiar with modern rocket vernacular so I recommend “Hydrolox Engine” and “Methalox Engine” respectively. Keeps it brief and also shouldn’t throw anyone for a loop.

If you are still worried about confusing people that are unfamiliar with those terms: you could add (color coded blue and green!) disclaimers at the bottom of the Part Description “This engine uses a LqdMethane/Oxidizer fuel mix” something like that.

[KawaiiLucy]

18 hours ago, Nertea said:

 If that was the case they'd definitely need to be pushed out into the tech tree! They should be at a middle point between the LFO/LH2O things currently in existence, which trade TWR for Isp.

Something by me is in the works; ETA:  soon^tm

Spoiler

CTT Patches for splitting rocketry into vaccum and booster lines, as well as reordering engine unlock order. I only need to finish icons for the nodes and it is good to go

 

[AmateurAstronaut1969]

Wow!

Just tried these Engines today, I was amazed. They look incredible and they mesh extremely well with stock/restock and other mods The effort put in is plain to see!

Keep it up 

[Starhelperdude]

I know this is wayyyy to early to ask, but would it be possible for you to include some rather ''exotical'' reactors in your upcoming revamp (after a break probably)? like thorium reactors (though special tanks would be needed probably) or Molten salt reactors?

[zakkpaz]

15 hours ago, Starhelperdude said:

I know this is wayyyy to early to ask, but would it be possible for you to include some rather ''exotical'' reactors in your upcoming revamp (after a break probably)? like thorium reactors (though special tanks would be needed probably) or Molten salt reactors?

a pebble-bed reactor that uses the FFT fission pellets would be a great late game addition

[Starhelperdude]

Just now, zakkpaz said:

a pebble-bed reactor that uses the FFT fission pellets would be a great late game addition

yeah, it would also be cool to have a reactor that refuels itself, like you just feed in the fission pellets or even fissionable particles and the reactor throws the Depleted fuel itself out

[Spaceman.Spiff]

20 hours ago, Starhelperdude said:

I know this is wayyyy to early to ask, but would it be possible for you to include some rather ''exotical'' reactors in your upcoming revamp (after a break probably)? like thorium reactors (though special tanks would be needed probably) or Molten salt reactors?

I think that the MS reactor is more likely.

Thorium would require a new resource, and I kinda doubt that the mod will go that far in terms of adding stuff. 

A molten salt reactor would be cool, though.

[Nertea]

No, very unlikely. 

[Cochies]

I've always thought FF is so good because it doesn't look like Interstellar.
Therefore, it always saddens me to see that many people want the FF to become more like Interstellar.

Edited March 8, 2021 by Cochies

[WarriorSabe]

5 hours ago, Cochies said:

I've always thought FF is so good because it doesn't look like Interstellar.
Therefore, it always saddens me to see that many people want the FF to become more like Interstellar.

I don't think it's the looks people are talking about, it's the stats. FFT engines have all their stats reduced so that they don't make good engines for traveling between stars in a timely manner (there's no tanks anywhere near big enough either) - the focus is entirely on interplanetary travel. The thing is, many of the engines would normally be interstellar-grade, so people expect FFT to give you engines that can get you from one star to the next.

[Nertea]

Huh.

• Laser ICF: 40 kN @ 520 000s  vs Hyde fusion rocket design: 40kN @ 265 000 s: oof 
• Fusion Z-pinch:  1.1 MN @ 365 000 s vs 'reality' 330 kN @ 350 000 s : just plain better
• Mirror cell fusion: 320 kN @ 200 000 s vs 'reality': 2.5 KN @ 158 000s : 

I believe this is quite generous. About the only one I've made worse than the paper I based it on (the Frisbee) has been shifted to 'only' 750 000s and a higher thrust than it would have otherwise. 

[CDSlice]

Yeah the end game FFT engines can easily take you intersteller, just perhaps in a more realistic manner than KSPI (I haven't played with that mod so I don't know for sure)

If you want to make getting between stars even easier, you can grab Angel's Blueshift mod for warp drives and jump gates you can set up between star systems. It is a bit cheaty with respect to the laws of physics but that's true with any mod that makes going intersteller faster/easier than FFT since FFT has most of the major engine designs that are physically possible for intersteller travel without requiring things like negative mass or other exotic mass/energy that likely can't actually exist.

[Starhelperdude]

1 hour ago, CDSlice said:

Yeah the end game FFT engines can easily take you intersteller, just perhaps in a more realistic manner than KSPI (I haven't played with that mod so I don't know for sure)

If you want to make getting between stars even easier, you can grab Angel's Blueshift mod for warp drives and jump gates you can set up between star systems. It is a bit cheaty with respect to the laws of physics but that's true with any mod that makes going intersteller faster/easier than FFT since FFT has most of the major engine designs that are physically possible for intersteller travel without requiring things like negative mass or other exotic mass/energy that likely can't actually exist.

also, you could just use fuel and use better time warp so you can warp thousands of years xD