Suggestion: Changing Fuel Type in Tanks

[fulgur]

This is quite time-consuming to code (you might have to edit all the part modules individually), but mods do do it so it is possible. This request came as a result of me making a spaceplane heavily using the Mk1-Mk2 adapters, which can only be fuelled with LfO. However, my nuclear powered spaceplane does not need all that O and so I have emptied all the oxidant tanks. But when in orbit in a test flight, I didn't have enough fuel to reach my Minmus refinery. It cost me a lot of aerodynamics and stability to make the plane longer and add more Lf. Then I realised: what if I could use all those empty oxidant tanks?

So this is my suggestion: allow us to change all tanks between liquid fuel only, for nuclear engines (the most commonly used when going interplanetary) and LfO (for launches). This will allow us to cut down on the number of parts (the separate, easily confusable Mk2 and Mk3 tanks) and use larger diameter interplanetary ships - at the moment the only liquid-only tanks are 1.25m, Mk2 and Mk3. No 1.875 ones and no 5m ones, and the 2.5m parts look horrible on a Mk2 or Mk3 ships in my opinion.

Edited January 24, 2020 by fulgur

[Signo]

I second this request.

[kerbiloid]

 

[VoidSquid]

Couldn't agree more, @fulgur !

As happy as I am to have mods for this, these mods are workarounds and the issue should be addressed by SQUAD, not modders.

Edited November 7, 2019 by VoidSquid

[RealKerbal3x]

On 11/7/2019 at 10:58 AM, kerbiloid said:

 

Or this:

Much more lightweight and simpler if you only want to switch between LFO and LF.

[VoidSquid]

Middle ground: 

 

[Tweeker]

On 11/6/2019 at 1:49 PM, fulgur said:

This is... not very simple to code, but mods do do it so it is possible. This request came as a result of me making a spaceplane heavily using the Mk3-Mk2 adapters, which can only be fuelled with LfO. However, my nuclear powered spaceplane does not need all that O and so I have emptied all the oxidant tanks. But when in orbit in a test flight, I didn't have enough fuel to reach my Minmus refinery. It cost me a lot of aerodynamics and stability to make the plane longer and add more oxidant. Then I realised: what if I could use all those empty oxidant tanks?

So this is my suggestion: allow us to change all tanks between liquid fuel only, for nuclear engines (the most commonly used when going interplanetary) and LfO (for launches). This will allow us to cut down on the number of parts (the separate, easily confusable Mk2 and Mk3 tanks) and use larger diameter interplanetary ships - at the moment the only liquid-only tanks are 1.25m, Mk2 and Mk3. No 1.875 ones and no 5m ones, and the 2.5m parts look horrible on a Mk2 or Mk3 ships in my opinion.

It actual should be very simple to code, 

this is an older example of the .cfg, but 

PART
{
	name = fuelTank_long
	module = Part
	author = NovaSilisko
	mesh = model.mu
	scale = 0.1
	node_stack_top = 0.0, 15, 0.0, 0.0, 1.0, 0.0
	node_stack_bottom = 0.0, -15.1, 0.0, 0.0, -1.0, 0.0
	node_attach = 5.01, 0.0, 0.0, 1.0, 0.0, 0.0, 1
	TechRequired = fuelSystems
	entryCost = 4800
	cost = 800
	category = FuelTank
	subcategory = 0
	title = FL-T800 Fuel Tank
	manufacturer = Jebediah Kerman's Junkyard and Spacecraft Parts Co
	description = A stretched variant of the FL-T400, the FL-T800 holds twice the fuel in a slightly stronger container. The black stripes along the side make the rocket go faster, our engineers tell us.
	attachRules = 1,1,1,1,0
	mass = 0.5
	dragModelType = default
	maximum_drag = 0.2
	minimum_drag = 0.3
	angularDrag = 2
	crashTolerance = 6
	breakingForce = 50
	breakingTorque = 50
	maxTemp = 2000 // = 2900
	bulkheadProfiles = size1, srf
	RESOURCE
	{
		name = LiquidFuel
		amount = 360
		maxAmount = 360
	}
	RESOURCE
	{
		name = Oxidizer
		amount = 440
		maxAmount = 440
	}
}

The Bold red part of the .config that effects how much, and what kind of fuel is loaded in the tank. 

All the parts could have this changed  to be switchable between 3 or 4 different  setups in the VAB, just as the paint scheme is changed now. 

It would be very low-level programming, mostly defining the capacity of each tank/part in LFO, rocket fuel, monoprop, etc. 

 

 

[EnderKid2]

Verily

[James M]

Please Squad. Next QoL update. 

[zer0Kerbal]

 

[fulgur]

That is not the point, I have Snark's Simple Fuel Switch now.

The point is that it should be stock, because the 4 fuel types (Lf, LfO, mono and Xe) are equally useful for many applications, and most space-based craft are not planes, but forced to use Mk3 parts as they are the ones which have Lf...

[dave1904]

2 hours ago, fulgur said:

That is not the point, I have Snark's Simple Fuel Switch now.

The point is that it should be stock, because the 4 fuel types (Lf, LfO, mono and Xe) are equally useful for many applications, and most space-based craft are not planes, but forced to use Mk3 parts as they are the ones which have Lf...

nothing more frustrating than saying that mods can do it in the first sentence and have every fuel switch mod posted   

[VoidSquid]

I totally agree with @fulgur, nothing to add. 

Funny thing, the base functionality of several excellent mods has been incorporated in KSP over time, still, for most of them, I still prefer the mod version as the in-game kind of feels awkward.

My thanks to the respective mod creators and maintainers, just because some functionality is now part of the base game doesn't make those mode obsolete, just the contrary  

 

Edited January 25, 2020 by VoidSquid

[Klapaucius]

This is  a great idea.  If I can have an all oxygen tank, I can pair that efficiently with a set of FAT-455 wings for creating planes for Duna and Eve (or Tekto).--or half and half wings of course.

[JadeOfMaar]

On 11/13/2019 at 3:16 AM, Tweeker said:

The Bold red part of the .config that effects how much, and what kind of fuel is loaded in the tank. 

All the parts could have this changed  to be switchable between 3 or 4 different  setups in the VAB, just as the paint scheme is changed now. 

It would be very low-level programming, mostly defining the capacity of each tank/part in LFO, rocket fuel, monoprop, etc. 

A lot of modders got upset when the variant system arrived and it didn't provide fuel switching. Why on Earth did Squad not deliver this? is a burning question. I anticipate there would be a great headache for Squad to add that in later on and potentially revise the variant config structure, which will (on one hand) bring relief to mod makers, but on the other hand, also upset them: "Oh nowwww you fix this." Meanwhile the fuel and mesh switch mods keep on growing or are already fully matured.

If stock variant fuel switching does arrive, it will be a few years late and waiting on it will be foolish.

If Squad does it then there would be a huge gain to it. Several redundant stock parts can be deleted and that will potentially save on performance or at least, it will save on trouble navigating part selection. Until then, us modders roll our own solution and we carry on.

Snark's SimpleFuelSwitch is minimal and the most stockalike solution so I urge @fulgur to use it. Don't wait on Squad for something so basic, so powerful, already available in a tiny mod. And remember, KSP is made to be modded. KSP is a blank canvas, and mods are your art tools. Squad will not deliver everything that's asked of them for that reason.

As for me, what I've done with B9 Part Switch is more than enough, and zer0kerbal's offering trims this down to just the stock stuff.

Edited January 28, 2020 by JadeOfMaar

[Mortimer Kerman]

We all need this!