Empty Fuel Tanks Mod

[Captain Sierra]

I'm working on reconfiguring the fuel tanks from both stock game (and a few other mods as well) to have 0 starting resources. How many people would be interested in this? I know I need it because I need to launch a massive tanker stage for my latest project, the Lazarus. (tanker stage has 9 orange rockomax tanks) The question here is should I take the time to put this on spaceport? Note, I am even making empty monopropellant and xenon tanks, just in case people do need them.

[painking]

I think it's as easy as opening the .cfg and editing them to be empty, not to mention I'm fairly certain someone already beat it to you. You can get empty stock and KW rocketry fuel tanks on the spaceport.

[acealeam]

Yes I would, but if possible, could you make it a plugin that can configure the amount?

[Jason Cox]

I'd download it, though honestly I wish they had (or a mod had) an option to edit the fuel loadout while on the pad so that you can drag a slider around and adjust your loadout on a per-tank basis.

[Captain Sierra]

Yall are right, that'd be more convinient. I'm no coding master so don't keep waiting for me to do that. All I'm doing is the config file edit, which isn't too hard if you aren't overwhelmed by the code.

It certainly is a good idea to make a plugin that lets you set fuel levels for various tanks on the pad.

[Captain Sierra]

Has said person done RCS and xenon tanks and KSP X tanks? Yes, it is that easy. All you have to do is copy the part folder, open the config file and set the resources to 0 whilst leaving the maximum resources alone. But for those who don't want to do that for some reason or another, I'm planning on making this available.

[stupid_chris]

Guys, there is a mod that has all the stock fuel tanks emptied, and there is also a mod that allows you to edit the amount of fuel in your fuel tanks on the pad and actively transfer while flying using a plugin.

Empty fuel tanks mod and mod to modify the amount of fuel in your tanks.

[Captain Sierra]

Well, downloading someone else work is no fun, so I'm doing it myself. I'm already halfway done. The question is do i keep this for myself or market it. Besides, I'm doing more than stock tanks.

EDIT: This is partially an experiment to see if I can not screw up the coding, which so far I haven't.

[Cashen]

The Modular Fuel System's basic version allows you to change the amount of fuel in each tank in the VAB before launch, so you can have empty tanks, or whatever amount of fuel you desire. It works with stock tanks, KW Rocketry, B9 Aerospace, and AEIS Aerospace. You do it right from the Action Groups menu without having to make separate empty tank parts.

[stupid_chris]

TAC fuel balancer works with every single part that contains a resource, and can not only be used to modify the amount it has on liftoff, but to transfer actively from any tank to any other tanks, from multiple tanks at the same time, to balance everything in every tank, etc. Once you have that, you don't need empty tanks anymore really.

[Cashen]

TAC fuel balancer works with every single part that contains a resource, and can not only be used to modify the amount it has on liftoff, but to transfer actively from any tank to any other tanks, from multiple tanks at the same time, to balance everything in every tank, etc. Once you have that, you don't need empty tanks anymore really.

I find the idea of empty tanks at liftoff useful in some instances. If I am launching a big interplanetary craft, I may decide to have the craft's tanks empty to make it much lighter, so a smaller ascent stage can get it into orbit, where it can dock with an orbital propellant depot to fill up before the interplanetary burn.

[Captain Sierra]

I find the idea of empty tanks at liftoff useful in some instances. If I am launching a big interplanetary craft, I may decide to have the craft's tanks empty to make it much lighter, so a smaller ascent stage can get it into orbit, where it can dock with an orbital propellant depot to fill up before the interplanetary burn.

That is exactly what I am doing. The fuel tank stage for my massive mobile interplanetary kethane base has 9 orange rockomax tanks. That alone weighs almost as much as my standard heavy launcher if not more. I need them empty and personally, I find it more satisfying manipulating the configs rather than using a slider on a plugin. The game feels a lot more like mine with my own tweaked parts rather than just someone else's mod parts. I even made empty RCS modules (because that stuff is heavy too).

[stupid_chris]

I find the idea of empty tanks at liftoff useful in some instances. If I am launching a big interplanetary craft, I may decide to have the craft's tanks empty to make it much lighter, so a smaller ascent stage can get it into orbit, where it can dock with an orbital propellant depot to fill up before the interplanetary burn.

You can empty the tank yourself before lifting off. You can manually edit the amount in it if you want too. It even works with batteries, monopropellant tanks, Kethane tanks, xenon gas tanks, and SRBs (you could half fill them if you want to, although I don't see the use). It even works with modded ressources. You can put the amount you want in them prior to liftoff. Then after liftoff, it can serve as a tool to balance out your fuel and transfer fuel around easily, as long as it follows fuel flow rules.

[Captain Sierra]

But that isn't nearly as satisfying as editing the config files yourself. At least I think so.

[stupid_chris]

But that isn't nearly as satisfying as editing the config files yourself. At least I think so.

Oh go forth if you are having fun, nothing can stop you! But you can't perfectly balance fuel through your tanks with config edits

[Captain Sierra]

I don't need to. I just need something that doesn't feel like I'm lifting tons of rocket fuel XD

[Cashen]

That is exactly what I am doing. The fuel tank stage for my massive mobile interplanetary kethane base has 9 orange rockomax tanks. That alone weighs almost as much as my standard heavy launcher if not more. I need them empty and personally, I find it more satisfying manipulating the configs rather than using a slider on a plugin. The game feels a lot more like mine with my own tweaked parts rather than just someone else's mod parts. I even made empty RCS modules (because that stuff is heavy too).

There is a stock empty tanks mod on the Spaceport and I had a look at it, changing the configs is easy so I briefly thought of making empty versions of the KW tanks and such, but then I found Modular Fuel System and decided to use that instead. The advanced version even adds liquid oxygen and liquid hydrogen as alternative propellants that have different properties from the stock liquid fuel and oxidizer, which I've thought of playing around with. Kethane is supported as well.

[KhaosCorp]

This is only a good idea if the 'mod' were to only contain replacement config files.

You dont want to make it so that the only tank option for a certain tank is empty. And you don't want to create bigger memory footprint than you have to.

The best solution to empty tank post 0.20 is config piggybacking:

Simply open the config for the tank you want to use empty, copy the ENTIRE config info, paste it below the original info. Then change the name, and desired values in the copy version.

Now you have 2 parts, 1 model, 1 texture, and 1 config for both, easypeasy =)

[Agent86]

I know it's already been answered, but my untechnical solution would be to attach a radial engine by decoupler to the the side of the tank, fire that engine on the pad, then go make a coffee while it drains the tank and goes nowhere

[EndlessWaves]

I find the idea of empty tanks at liftoff useful in some instances. If I am launching a big interplanetary craft, I may decide to have the craft's tanks empty to make it much lighter, so a smaller ascent stage can get it into orbit

Only if you leave the fuel in the interplanetary craft completely untouched. If you launch with full fuel tanks and string a fuel line so the fuel is burned by the ascent stage then you'll end up with a much lighter, smaller craft overall than using empty tanks.

[Cashen]

Only if you leave the fuel in the interplanetary craft completely untouched. If you launch with full fuel tanks and string a fuel line so the fuel is burned by the ascent stage then you'll end up with a much lighter, smaller craft overall than using empty tanks.

I'm not sure the math checks out on that one. The end result of launching with the upper stage empty, or fuel ducted backwards, is the same: The empty craft in orbit. Since the mass in orbit is the same, the amount of propellant expended should also be the same or similar to get it there. But I could be wrong. Might be interesting to experiment. Keep in mind that I'm only considering the amount of propellant required to do a job, which is what I meant in my original suggestion.

[Geschosskopf]

To me, empty tanks are a lot more useful if they're empty to start with in the VAB/SPH, or can be made to become empty there. This is because if you have to use a full tank when building the ship, the CoM is based on that, as are all the delta-V stats shown in things like Kerbal Engineer and MechJeb. Thus, if you have to have full tanks in the VAB/SPH, you can't tell where to put your center of lift, nor how to balance your RCS, nor how much delat-V you really need to lift the thing (without doing manual math). Also, if you need to lift a big cluster of empty tanks, the rocket that can do that might be crushed by the weight of the full tanks before they dump all their fuel on the launch pad.

Empty tank mods overcome all these problems by having empty tanks in the VAB/SPH. Problem is, they add yet more parts to the list, making all parts that much harder to find. And at present, all empty tank mods use either stock or KW tanks and look just like them, so it's easy to grab the empty when you want the full version, and vice versa. TAC doesn't add any parts but doesn't work in the VAB/SPH, but is quite useful in many other ways.

Ideally, TAC could be made to work in the VAB/SPH. But until that happens, empty tank mods are useful enough to justify the clutter they create. HOWEVER, if you're going to make an empty tank mod, PLEASE retexture the tank models (or make new ones) so their icons are immediately obvious for what they are, to avoid the confusion caused by the look-alike mods already out there.