[WIP] Coatl Aerospace ProbesPlus Dev Thread [Beta] 10/19/2020 (1.8-1.10)

[Phineas Freak]

Nothing really constructive to add but...there is so much win in this thread! @akron your work is absolutely amazing!

[Jimbodiah]

@enlait: in real life Kerolox and hydrolox are only used in lifters, monoprop (sinlge) or hypergolic (two-part) are used for orbital craft as these can be fired up as many times as you want. They have lower isp but can be restarted, whereas the kero- ad hydrolox engines are hard to start a second or third time in comparisson. There is no gaming reason to have anyhing other than an LF/O type engine, but think of it as immersion. If you use RO then this s even implemented there, you can only fire your engine 1-2 times in many occasions, and ussualy only from a high throttle percentage. Akron is just trying to reflect the real world engines.

[enlait]

1 hour ago, Jimbodiah said:

@enlait: If you use RO then this s even implemented there, you can only fire your engine 1-2 times in many occasions, and usualy only from a high throttle percentage.

This particular part sounds interesting. It seems to be provided by Real Fuels mod, too bad it's not 1.2 yet. Anyway, thanks for the tip!

[Theysen]

1 hour ago, Jimbodiah said:

@enlait: in real life Kerolox and hydrolox are only used in lifters, monoprop (sinlge) or hypergolic (two-part) are used for orbital craft as these can be fired up as many times as you want. They have lower isp but can be restarted, whereas the kero- ad hydrolox engines are hard to start a second or third time in comparisson. There is no gaming reason to have anyhing other than an LF/O type engine, but think of it as immersion. If you use RO then this s even implemented there, you can only fire your engine 1-2 times in many occasions, and ussualy only from a high throttle percentage. Akron is just trying to reflect the real world engines.

I am nitpicky but there are several hydrolox / kerolox upper engines which can be restarted quite often in theory - you have hypergolics as fuel for most deep space / long term missions because they don't boil off and can be used at any time you want. Also the tankage can be a lot smaller than compared to high energy lifting fuel combinations. 

 

Restartability depends on the way the engine is ignited and i personally think we're getting there with the likes of SpaceX and maybe ACES to have good ratios of mission time and high energy fuels for on orbit stuff. As usual, you have customers and a market for application - build / invest in it . You don't have the market for it - go with what is known and works and don't bother with research. 

[CobaltWolf]

With BDB @Jso has always been an extremely strong believer in using the real-world ISPs, and tweaking balance with mass. It's generally been working for us pretty well.

[Theysen]

3 hours ago, CobaltWolf said:

With BDB @Jso has always been an extremely strong believer in using the real-world ISPs, and tweaking balance with mass. It's generally been working for us pretty well.

Meh, really? I might see it working out as long as you stick to the specific parts which are meant to be going with each other, but it's Lego and why would I use anything different on a custom design which has other parts than the op engine which comes with mod XY? I know, self induced role play and restrictions but I don't think it might be *that* suitable towards such a highly modular mod which has good use in other vessels and designs. Or vice versa. I don't want to bring a 1t science arm onto a small little probe just because one mod dictates so because it uses real isp as balance basis. Just my 2 cents on that  but whatever you do, there is MM and a whole universe in our own heads how the things should be  

[CobaltWolf]

17 minutes ago, Theysen said:

Meh, really? I might see it working out as long as you stick to the specific parts which are meant to be going with each other, but it's Lego and why would I use anything different on a custom design which has other parts than the op engine which comes with mod XY? I know, self induced role play and restrictions but I don't think it might be *that* suitable towards such a highly modular mod which has good use in other vessels and designs. Or vice versa. I don't want to bring a 1t science arm onto a small little probe just because one mod dictates so because it uses real isp as balance basis. Just my 2 cents on that  but whatever you do, there is MM and a whole universe in our own heads how the things should be  

I'm not sure what you mean. Unless you have a specific comment on BDB (which IS meant to be lego) that somehow demonstrates that the approach is invalid, then I don't follow your train of thought. Kerbal ISPs are, by and large, near to real-world performances for kerolox + storable propellants, and in the case of propellants such as hydrolox, there are other ways of balancing them - having to have large volume tanks to hold the propellants, low power, and of course the expense. To the point where I often DON'T use cryogenic propellants, since they don't scale down well in terms of dV for upper stages. I'm still scratching my head at your comment. Real world ISPs are fairly similar to Kerbal ISPs. The difference is that everything in Kerbal is very, very heavy - which we maintain in our balance.

EDIT: Also, just to throw 2c into the ignitions thing - 'hypergolic', while usually associated with being easier to store because they'retypically not cryogenic (LOX is, btw), are propellants that ignite on contact with eachother - making restarting them significantly easier. Whereas you have to have some sort of igniter for kerolox/hydrolox, which is naturally finite.

Edited November 5, 2016 by CobaltWolf

[akron]

9 hours ago, enlait said:

I'm not sure if that has been asked before; but why do lahar and linkor LFO engines have such high ISP? 345 starting ISP is already enough to make all other small stock engines obsolete, and 355 after upgrades is higher than any LFO engine of any size. Other mods I have (eg SpaceY, RLA, MRS) also take those number as a baseline: 345 ISP is considered a "highly optimized" LFO engine, and 350 is a cap for LFO propulsion.

On a side note, I understand why monoprop engines (jib and trident) have low ISP realistically, but they are also heavier than their two-component fuel competitors, so they seem kinda useless...

Good conversation point! Thank you guys for your responses too!  

I am going to be outright honest and say that fuel mixture consideration had nothing to do with it, you give me too much credit. The decision is purely gameplay based so I threw realism out. I made a fuel tank to go with each engine and each was designed to "fit" in my Tatsujin probe. Upon giving all the engines somewhat realistic stats for an early pass, I realized that the trident/tank combo vastly outperformed the Lahar, specially because it could use the probe's internal monoprop as well. This would have caused the Trident to be preferred over the Lahar. In an effort to balance both engines together, Lahar was boosted in ISP and Trident got a mass nerf. Thats the basic pure reason for it. I expected to get a certain dV out of each tank/engine combo and this was the only way to do it.

Other stock engines still have their uses and, while I try to balance for stock, I realized that most people who use my mod will also have another launcher/engine mod to go along with it; often with better engines as well. I can potentially revisit this later on, when the mod has more engine variety, and space the engine stats out. At least you now know my reasoning here. I do not hesitate to throw out accuracy in favor of reduced complexity or gameplay, in both the parts design and their stats.

All good points! I welcome all feedback because I don't have any alpha testers or anyone helping me balance things out. I'll try and get a list of engine stats ready and maybe you guys can look it over and throw suggestions  

Cheers

[CobaltWolf]

@akron well Astronautix gives the KTDU-425A an ISP of 315 seconds. That's certainly a bit high IMO, I'd figure out what sort of capability you'd need for the canon Venera flight in terms of dV (no real point in making real world inspired parts if they can't be put together and complete their mission?), look at what sort of stats similar engines have in KSP, and go from there.

Perhaps lower the ISP of the MAVEN engines, but keep them a bit lighter, while this is a bit heavier but has higher ISP? As a quick refresher, on smaller stages/spacecraft, dry mass is more important for dV than your ISP (which is why the 48-7S is useful despite the ISP), whereas higher ISP becomes more important the bigger the stage is - if the total mass of the system is higher, and there's significantly more fuel, having slightly less weight is less important than using that fuel effectively.

I just found a source that says the MAVEN engines had an ISP of ~230 seconds. But since the system is much smaller, lighter, and likely has a higher proportion of propellant compared to a big, heavy, Vega, they probably wind up with similar capability. And MAVEN uses hydrazine monopropellant, which as mentioned above doesn't really compare to even storable bipropellants when it comes to ISP, but you simplify the system by only needing one set of tanks (two maybe, you might need helium for pressurization) which also provides additional mass savings.

My point being that, our experience has been that real world ISPs have translated well into gameplay balance for us, and building off the real-world differences in the way that things behave has provided a lot of insight for how to fit parts into different niches.

EDIT: Actually 315 on a vacuum optimized engine isn't that hard. Don't mind me.

EDIT2: Fregat has an ISP of 327 seconds, which would be a significant enough nerf to be worth trying IMO. And if it's still OP, giving it a bit more dry mass - there's quite a bit of stuff crammed onto there besides just the engines and tanks - would probably make it pretty perfect.

Edited November 5, 2016 by CobaltWolf

[akron]

@CobaltWolf Fregat is getting resized like 60% bigger, so I'll revisit it soon. It needs a boost because right now it has very little dV. I need it to do kerbsynchronous insertions.  I'll need to make the larger-tank version for Duan transfers. I'll also have to spend a lot of time re-doing the upgrade nodes. It's been very confusing.

[enlait]

I think rather then dry mass, ISP gets more important the mode dV you're trying to squeeze. So no matter how small your payload is, ISP will be important if you try to launch it far enough. And this is why that 48-7S is mostly useful for short powerful bursts (landing/takeoff).

Balance-wise there's also a thing with Jib weighting the same, and having same ISP as stock puff, while having 4 times less power.

@akron I think I got an issue here, though I can't say whether some other mod is involved... but CA-A100 does not seem to work as relay when upgraded. Changed the non-upgraded type to relay and viola - my comm net is up. Is changing antenna type by upgrade legit?

[CobaltWolf]

16 minutes ago, enlait said:

I think rather then dry mass, ISP gets more important the mode dV you're trying to squeeze. So no matter how small your payload is, ISP will be important if you try to launch it far enough. And this is why that 48-7S is mostly useful for short powerful bursts (landing/takeoff).

Balance-wise there's also a thing with Jib weighting the same, and having same ISP as stock puff, while having 4 times less power.

@akron I think I got an issue here, though I can't say whether some other mod is involved... but CA-A100 does not seem to work as relay when upgraded. Changed the non-upgraded type to relay and viola - my comm net is up. Is changing antenna type by upgrade legit?

For more dV, you'd need for fuel. At that point your system is big enough that ISP has a bigger effect than weight. But with probes and other small things like landers, your ISP can very easily be less important than mass. It doesn't matter if you have 10% more ISP if the engine makes the dry mass of your spacecraft 20% heavier. But if you're packing more equipment, more fuel tanks, and the total change in dry mass is more like 5%, but you still have a 10% ISP gain, then you benefit from the higher ISP. Follow?  

[enlait]

10 minutes ago, CobaltWolf said:

For more dV, you'd need for fuel. At that point your system is big enough that ISP has a bigger effect than weight. But with probes and other small things like landers, your ISP can very easily be less important than mass. It doesn't matter if you have 10% more ISP if the engine makes the dry mass of your spacecraft 20% heavier. But if you're packing more equipment, more fuel tanks, and the total change in dry mass is more like 5%, but you still have a 10% ISP gain, then you benefit from the higher ISP. Follow?  

That was pretty much my point. On the other hand, if you have 10% more ISP and an engine weights the same but is 20% weaker, it is still better for 100% orbital maneuvers, and you can actually decrease mass by saving on fuel and tanks. This is why I consider an engine with 355 ISP and 13 TWR overpowered.

[akron]

7 minutes ago, enlait said:

That was pretty much my point. On the other hand, if you have 10% more ISP and an engine weights the same but is 20% weaker, it is still better for 100% orbital maneuvers, and you can actually decrease mass by saving on fuel and tanks. This is why I consider an engine with 355 ISP and 13 TWR overpowered.

The only other way to increase the dV of the Lahar propulsion set was to increase the capacity of the fuel tank, which was not an option for me. I wanted both propulsion sets to have comparable dV when used with Tatsujin. It is purely a game balance thing which  forced OP LFO stats on Lahar. Limited engine variety keeps me from being able to change much right now. Let me get more engines done and I can rebalance the stats.

I may consider just moving the Lahar to a later tech node to justify the better tech.

Thoughts?

 

Mobile site post

[enlait]

18 minutes ago, akron said:

Thoughts?

• maybe decrease non-upgraded version ISP more (330?), and upgrade in bigger steps.
• maybe decrease thrust, so that engine would have worse TWR - that won't affect dV
• does it really have to be over 350?

Quote

Limited engine variety keeps me from being able to change much right now. Let me get more engines done and I can rebalance the stats.

Please do that ^^

Edited November 5, 2016 by enlait

[msnbcorp]

Hi, just to say, it would be good if you can integrate you're mod with ETT. Currently it's not playable with ETT, it break too much the career mods.

[Jimbodiah]

Someone help Akron and write an ETT patch for him     I think CTT is more widely used and supported.

Edited November 6, 2016 by Jimbodiah

[CobaltWolf]

56 minutes ago, enlait said:

That was pretty much my point. On the other hand, if you have 10% more ISP and an engine weights the same but is 20% weaker, it is still better for 100% orbital maneuvers, and you can actually decrease mass by saving on fuel and tanks. This is why I consider an engine with 355 ISP and 13 TWR overpowered.

I agreed that the Lahar and Linkor are OP. I think there might be a misunderstanding here - I'm not disagreeing with you on that. 355 ISP is nearly 30 seconds more than the highest real engine I mentioned. But I wasn't talking about engines weighing the same, which I think is where we lose each other.

I would like to try and be more clear on my response to this point:

1 hour ago, enlait said:

I think rather then dry mass, ISP gets more important the mode dV you're trying to squeeze. So no matter how small your payload is, ISP will be important if you try to launch it far enough.

That's not true. There is absolutely a point where you get more dV out of having a lighter, less efficient engine than a heavier, more efficient engine. A monopropellant engine should be lighter, since it's a much simple engine - basically just a valve that squirts hydrazine over a catalyst bed and out the nozzle. So even though you lose some ISP, you'd get more dV because the reduced mass of the system means that your propellant doesn't have to push as much mass, so it accelerates more. In order to get more dV in that situation, the spacecraft with the higher ISP would need to add more fuel, which means the affect the weight of the engines have on the entire system is less important. But at that point you've changed the equation to favor one engine instead of the other - which is good. They both have situations where they're 'best'. But to say that higher ISP is better 100% of the time is incorrect. And KSP engines are significantly heavier than they are IRL, AND you save on having to have separate fuel tanks, whereas a monopropellant probe shares fuel between the attitude thrusters and the main engines, or better yet, uses the attitude thrusters for manuevers.

If you want to have an engine that weighs the same, and has higher ISP, and is weaker thrust, then yes, that would 100% of the time be better for orbital manuevers. But I'm not talking about that. That's the difference between a purely orbital engine and... a weaker lifter engine? A second stage that needs to TWR to avoid falling out of space? Thrust is irrelevant for orbital stuff, apart from considering the Oberth effect (Not to say it doesn't matter balance-wise!)

 

17 minutes ago, msnbcorp said:

Hi, just to say, it would be good if you can integrate you're mod with ETT. Currently it's not playable with ETT, it break too much the career mods.

Hit up @Probus over at the ETT thread. While I'm sure he'd appreciate mod authors handing him some configs, that is his mod; @akron has quite a bit on his plate already.

[akron]

11 hours ago, msnbcorp said:

Hi, just to say, it would be good if you can integrate you're mod with ETT. Currently it's not playable with ETT, it break too much the career mods.

Like @CobaltWolf and @Jimbodiah mentioned, I'd welcome help. I have a lot of things to get ready and it takes a lot of time to figure out how other mods work to write configs. Configs for AntennaRange and RemoteTech and others were done by the gracious work of a number of folks who chipped in. That being said, I can get to it, just eventually. Not very high on the priority list right now. And I do welcome the suggestions for support to other mods.

Update

I think I finished all the modeling I need to do on the orbiter, except minor tweaks and fixes. Next are tweaks to Beale's Fomalhaut plus the parachute and heatshield. Then, ugh, UV and textures. Below you'll see the new engine bay, Stack separator, Magnetometer, Camera assembly, Thermal system, and those cute little things sticking out of the solar panels.

I also started working on a spreadsheet of engine stats to plan and balance things for the future. I'll post a link once I think it's decent.

~Cheers

 

The bloody thing is over 10.5k tris (WITHOUT the lander or heatshield ). I'm hurting. If I keep up with this level of detail, it's gonna force me to redo many old parts... darned Russian parts

[msnbcorp]

5 hours ago, akron said:

Like @CobaltWolf and @Jimbodiah mentioned, I'd welcome help. I have a lot of things to get ready and it takes a lot of time to figure out how other mods work to write configs. Configs for AntennaRange and RemoteTech and others were done by the gracious work of a number of folks who chipped in. That being said, I can get to it, just eventually. Not very high on the priority list right now. And I do welcome the suggestions for support to other mods.

Sorry but i can't currently, i am playing for the first time with ETT, so it would necessite spoilers in my game and i don't well know the current balancing of the node so i could not place your nodes in the right places ^^.

Truely I think that if you have time, integration in ETT and CTT are a priority as every single player use one of them ^^. But if i explore the tree before you have time, i will remembered to do it

 

Edited November 6, 2016 by msnbcorp

[Jimbodiah]

I'd rather see Akron focus on new parts than more techtree integrations at this point   This is why we have input from other users here that can help out with this tedious stuff as his mod is on Github where the community can contribute. 

The parts are balanced fairly nicely in the stock tree and CTT only expands on stock nodes, so no changes are needed to use CTT: you can use the extra CTT nodes if you want through a patch, but all the parts are still available at the stock nodes even if you don't. The only thing I have changed is to put the 1x2 and 1x4 folding panels one node earlier, together with the other stock small folding panels to have them available a bit sooner, but the rest seems OK to me even in CTT. Spreading out parts too thin over different nodes, just because you can, is not always a good idea.

I tend to use CTT not because I want a complete re-balance of part locations in the tree (which it doesn't do), but to add more nodes and make it harder to get them with up to 10K science nodes instead of 1K. This way future tech can be placed way up the tree instead of being unlocked after two landings on Minmus as per the stock tree, or one landing on the Mun if you use a cheat lab that gives a 6x science yield.

[akron]

10 hours ago, msnbcorp said:

Sorry but i can't currently, i am playing for the first time with ETT, so it would necessite spoilers in my game and i don't well know the current balancing of the node so i could not place your nodes in the right places ^^.

Truely I think that if you have time, integration in ETT and CTT are a priority as every single player use one of them ^^. But if i explore the tree before you have time, i will remembered to do it

CTT is much more widely supported than ETT, from what I can tell. But I disagree in that every player uses either. I mean, I don't  I'll look at what time I have available when I approach completion of this next update. Hopefully you or someone else might be free then and help me get it together.

Anyway, I tried to take advantage of the "extra" hour I got with daylight savings change and started texture work. I tried a look with rivets to make it look more unrefined and industrial since I cannot afford all the piping that the real one has (The core is 3020 tris!). Any thoughts before I move on to the rest of its parts?

Render time:

 

EDIT: By the way, since I don't have time to play the game anymore... Does this work in 1.2.1? Anyone having issues?

Edited November 7, 2016 by akron

[Jimbodiah]

Nice bedpan!

 

CTT expands upon the stock tree, it does not rearrange or change it. It adds extra branches for a number of categories (solar panels, radiators, life-support, colonization, rovers etc) and has 3-4 extra nodes at the end so the future tech parts can be placed in harder to obtain nodes. Even without any patch, the stock mod can work in CTT. Most players just use the stock tree, and I think CTT is the most popular techtree mod. 

ETT rearranges the entire techtree and will not work properly without dedicated patches to my knowledge.

[msnbcorp]

Yes it works, in this particular case it just put parts in categories with an "a-priori" . So it works but it is not balanced at all (overkill part like the all in one probe core with rcs/wheel etc... at the near begenning etc...)

[akron]

 

I might make the nozzle a little grey-er. No idea what these old Russian nozzles are made of, and it looks different in every picture I have of it so I just went for a generic look. Thoughts?

EDIT: By the way, I decided to call the engine 'Kurt' after Vladimir G. Kurt, who suggested the Venus-Halley missions, Vega 1 & 2.

 

Also, since I don't have time to play the game anymore, is anyone having issues with the mod in KSP 1.2.1?

Edited November 8, 2016 by akron