[QoL] KSP2 desperately needs a native "B9 Part Switcher" style tank selector for fuel tanks.

[HephaistosFnord]

This feels pretty critical.

The current situation
- All the Mk2 and Mk3 Spaceplane 'adapter' parts currently only come in Methalox flavors 
- Having separate Methalox and Methane tank subcategories is going to be a real pain, as more and more parts get added.
- The later the devs wait to build a fuel tank switcher, the more likely it is that some other development complicates it.

Ideal behavior
- There should only be one subcategory for 'Methalox' tanks, and the 'part menu' should have a simple drop-down with Methane, Oxidizer, and Methalox as the 3 options.
- Methalox mass ratio should change to 1:3.6, rather than 1:4, because this gives a perfect 1:2 *volume* ratio, for easy balancing
  (most of the supplied parts come in 1x, 2x, 4x and 8x volume options, so if you have a design that needs separated Oxidizer and Methane tanks, you can easily keep the correct ratio without having to calculate or tweak anything)
- Command modules with integrated RCS should be switchable between Monopropellant and Methalox
- Command modules *without* integrated RCS should have their integral Monopropellant tanks removed

Thus, the total fuel tank part subcategories become:
- Methalox (1.00x Methane / 1.80x Oxidizer / 0.33x Methane + 1.20x Oxidizer)
- Monopropellant
- Hydrogen
- Xenon
- Whatever future categories are needed

Can this please, please be done? Speaking from experience with KSP1 modding (I created the original RealFuels/ModularFuelSystem), it feels like this should be, at most, three days' work for a junior dev, it would *massively* improve QoL, and it's sufficiently foundational that it should probably happen sooner rather than later.

Edited October 15, 2023 by HephaistosFnord

[Safarte]

Totally agree with this suggestion, this would also greatly improve the modding experience for large parts of the game.

Edit: And if switching between models / materials is also added that would be even nicer.

Edited October 15, 2023 by Safarte

[HephaistosFnord]

11 minutes ago, Safarte said:

Totally agree with this suggestion, this would also greatly improve the modding experience for large parts of the game.

Edit: And if switching between models / materials is also added that would be even nicer.

Switching between models/materials would be awesome, but isn't really necessary for a "round one" pass.

If switching models/materials *is* doable, though, then it would be nice to have a fourth category of fuel tank, which combines the foil-covered Methalox pills/spheres/donuts + all the Monoprop tanks + all the Xenon tanks, into a single tank subcategory called "Service tanks", which can hold Methane, Oxidizer, Monopropellant, Xenon, or Hydrogen (with a different model/material based on what it's holding).

EDIT: That said, I wouldn't want any time spent on that project if it has any chance of delaying other current improvements, while my OP suggestion cluster genuinely does feel high-priority in comparison.

Edited October 15, 2023 by HephaistosFnord

[Bej Kerman]

Having separate but identical tanks for methalox and methane adds nothing to the game, so consider me on-board with this.

[Heretic391]

3 hours ago, HephaistosFnord said:

- There should only be one subcategory for 'Methalox' tanks, and the 'part menu' should have a simple drop-down with Methane, Oxidizer, and Methalox as the 3 options.
- Methalox mass ratio should change to 1:3.6, rather than 1:4, because this gives a perfect 1:2 *volume* ratio, for easy balancing
  (most of the supplied parts come in 1x, 2x, 4x and 8x volume options, so if you have a design that needs separated Oxidizer and Methane tanks, you can easily keep the correct ratio without having to calculate or tweak anything)
- Command modules with integrated RCS should be switchable between Monopropellant and Methalox
- Command modules *without* integrated RCS should have their integral Monopropellant tanks removed

This is a great suggestion, a basic thing like this shouldn't need a mod.

[HephaistosFnord]

If this is done, nosecones and structural adapters should also get a 'Service Tank' fuel switcher, with 'None (structural)' as the default.

[Royalswissarmyknife]

I agree but I think a different method to the B9 part switch way would be better for tanks.

Maybe a Simple adjustable fairing like slider where there's 0-10 segments for length / Diameter. 

Spoiler

Maybe if it went like 0.5, 1, 1,5 and etc. In length it would allow you to not have the longest tank and the shortest tank on top to get the right length you want.

It could also be linked to the tech tree where it increases the length you can make your tanks of certain diameters.

[HephaistosFnord]

9 minutes ago, Royalswissarmyknife said:

I agree but I think a different method to the B9 part switch way would be better for tanks.

Maybe a Simple adjustable fairing like slider where there's 0-10 segments for length / Diameter. 

  Reveal hidden contents

Maybe if it went like 0.5, 1, 1,5 and etc. In length it would allow you to not have the longest tank and the shortest tank on top to get the right length you want.

It could also be linked to the tech tree where it increases the length you can make your tanks of certain diameters.

Sure, but that's actual "procedural tanks", and is probably a bigger deal than just switching contents.

There are lots of technical reasons why I described the request precisely the way I did.

[Lowi_Sace]

We could also just call them liquid feul tanks again and being able to switch between Mehalox, hydrolox, methane, hydrogen and oxidiser. Would just decrease the amount of searching for tank and give every catagory of feul tank a lot of options to choose from. Also an options for engines with variants for methalox and hydrolox would be cool and handy

I like the idea of being able to use different feul types for RCS

 

 

[HephaistosFnord]

5 hours ago, Lowi_Sace said:

We could also just call them liquid feul tanks again and being able to switch between Mehalox, hydrolox, methane, hydrogen and oxidiser. Would just decrease the amount of searching for tank and give every catagory of feul tank a lot of options to choose from. Also an options for engines with variants for methalox and hydrolox would be cool and handy

I like the idea of being able to use different feul types for RCS

I think that hydrolox and hydrogen should be kept separate - the manufacturing methods and insulation requirements for hydrogen tankage are very different than for methalox.

Again, there are many specific and technical reasons why my proposal is what it is. That said, allowing methalox tanks (and nosecones) to hold 100% oxidizer would allow for hydrolox engines - this is incidentally exactly how the space shuttle worked. The big orange tank had hydrogen in the cylindrical part, and oxidizer in the nose cone part.