Is LiquidFuel less dense than water?

[MedwedianPresident]

I would like to know what substances in KSP are denser than water and which are not as dense. Can LiquidFuel be used as some sort of "Ligroin" to pull things down in water smoothly?

Let's assume that we are working on Kerbin.

Denser than water:

- Ore

Less dense than water:

[KnutG]

on the wiki ore is the heavyest material in KSP. i found this weights:

Ore 10kg / unit

Solid Fuel 7,5 kg/ unit

Liquid Fuel, Oxidizer and Inake Air (!) have 5kg / l

Monoprop 4kg / l

Ablator 1 kg / unit

Xenon Gas 0,1kg / unit

the only Tank that will sink is the full ore Tank - the other ones are swimming, so thats the density of water must be between 10 and 5 kg/ l I think. (i havnt tryed solid fuel yet)

[KerikBalm]

Well, is it really a matter of density of the substance, or a matter of the volume of the tank?

Some parts seem to contain more fuel per unit volume than others, at least judging on the 3d model.

An obvious example of this is a mk1 LF fusalage vs a mk2 LF fusalage

The 2.5m monoprop tank holds 3x the monoprop of the small one, but it seems to be more than 3x the volume... in fact if it were the same height, its volume would be 4x as big as the 1.25m tank... and I think its even taller.

Then consider the large ore tank vs the small one (lets not bother with the tiny ones yet).

They are the same height as far as I can tell... 1.25 vs 2.5m radius... so one part 4x the represented 3d volume ofthe other... but its full mass is 4.857x more than the small tank.

So... how is bouyancy calculated? is it based on the dimensions of the part?

Anyway, I'm sure if you .cfg file edited a part to be able to hold 100000 units of LF, it would sink.

It should be basically just mass/volume of the part.

Note that in KnutG's analysis above, we don't know the volume of a unit, and they are clearly not the same volume (just compare how many units of xenon are in 1.25m tank, vs how many units of xenon are in the 2.5m tank)

The mass per unit is meaningless for these calculations except to define the mass of a substance within the volume of a part.... which varies a bit by part

[NecroBones]

Most of the cylindrical rocket tanks have a consistent scaling of capacity with volume. I'm not sure how the radial monoprop or LF-only aircraft tanks compare.

[NathanKell]

Also, buoyancy has a 1.2x scalar, so effectively Kerbin's ocean has a density of 1.2t / m^3.

That means for a 2.3m^3 tank (i.e. of FL-T400 size) you need 2.76+ tonnes.

[EladDv]

Also, buoyancy has a 1.2x scalar, so effectively Kerbin's ocean has a density of 1.2t / m^3.

That means for a 2.3m^3 tank (i.e. of FL-T400 size) you need 2.76+ tonnes.

how are those things calculated exactly? the dimensions of the craft on the SPH/VAB or something more complex(probably drag cubes)

[NecroBones]

I think they said in the patch notes that the volume is estimated from the drag cubes, yes.

[problemecium]

My experimental findings say no. When I make a boat with a full liquid fuel tank, it sinks, but the same boat with an empty tank floats. This is also the case with MonoPropellant.

[Chaos_Klaus]

I think they said in the patch notes that the volume is estimated from the drag cubes, yes.

I don't even think the drag cubes have a volume in the typical sense. I thought they were just abstract objects that had faces with numbers ascociated to them.

Lift and drag in water is based on the drag cubes though, as mentioned by Nathan Kell on a stream. But that is for dynamic diving, not static diving by controlling boyancy.

[EladDv]

I don't even think the drag cubes have a volume in the typical sense. I thought they were just abstract objects that had faces with numbers ascociated to them.

Lift and drag in water is based on the drag cubes though, as mentioned by Nathan Kell on a stream. But that is for dynamic diving, not static diving by controlling boyancy.

well if you have 2 faces of a box(orthogonal ones) you could calculate the volume of the box. but i dont know how exactly he is calculating buoyancy, that would be useful for subs, I can also assure you that it's not by the dimensions that are displayed in the editor since for my subs to work it would take over 1K mT to sink but i got it with a third of that

[NathanKell]

If you have a box of known dimensions, and you have the projected area of the item on each of the box's faces, you can fairly easily guesstimate the item's actual total volume.