How do you guys do calculations when there aren't any units?

[munkeylord]

So, I've just started out KSP. And I'm craving to exercise my science skills from college. But, when I look at the vitals of various parts, they lack any units.

So, how do you guys do it? Are there good manuals?

[Kryxal]

There are ALWAYS units (though not always stated), part mass is in tons for instance. What in particular are you thinking of?

Incidentally, I think the fuel/oxidizer is in liters, and tanks indicate total mass of contents.

[mhoram]

Have you had a look at the wiki?

http://wiki.kerbalspaceprogram.com/wiki/Parts

There you can find description of parts and their specifications including units.

[Sirrobert]

Mods like Mechjeb and Kerbal Engineer will also give you a ton more data while building/flying your rockets

[tsotha]

Not every number has units. Units cancel on ratios of the same thing, for example.

Anyway you'll have to be more specific.

[Th3F3aR]

There is everything you need described on the link provided by mhoram

and every part ingame got everything you need.

When it comes to Burntime or the massreduction by fuelconsumption you have to dig a bit deeper on the wiki side.

But keep in mind Fuel/Oxidizer 10/11 -> 180Liter Fuel / 220Liter Oxidizer (Example for the FL-T400), which basically means 1,25T wet Weight for that part (is given in KSP) and 0,25 Dry (is at least given in wiki)

so you got 2 tons of "fuel" consisting of 180liters l-Fuel and 220liters Oxidizer. When you are at this point you got 2 choices:

1st: Dig deeper and calc fuelflow in liters

2nd: check out how many fuel your engines uses in kilogram (2000(Mass Fuell)/68,45(1xLV-T30)) -> Burntime

And of course be more specific as i just threw out some info you might never need

Edited October 13, 2014 by Th3F3aR
Typo on dryMass

[cantab]

The game gives masses in tonnes, speeds in m/s, and thrusts in kilonewtons. Distances are in various metric units (metres, kilometres, megametres, etc).

Fuel is given in arbitrary volume units. There is no in-game evidence they're litres and good reason to think they're not. Liquid fuel and oxidizer both have densities of 5 kg/unit, monoprop is 4 kg/unit, xenon I forget.

Electricity is given in arbitrary units. 1 Ec = 1 kilojoule seems reasonable when considering solar panel and RTG output.

[Orionkermin]

Something that may be easy for a new player to miss, is that you can right click on the part thumbnails in the VAB/SPH to bring up more information.

[Pecan]

...Fuel is given in arbitrary volume units. There is no in-game evidence they're litres and good reason to think they're not. Liquid fuel and oxidizer both have densities of 5 kg/unit...

A little thing to watch out for is that not all fuel tanks are equal. The very small and 3.5m tanks mass more per fuel unit they contain than the others. The very small tanks are more expensive per fuel unit as well.

[Red Iron Crown]

Fuel is given in arbitrary volume units. There is no in-game evidence they're litres and good reason to think they're not. Liquid fuel and oxidizer both have densities of 5 kg/unit, monoprop is 4 kg/unit, xenon I forget.

Xenon is in 0.1kg units.

Why aren't all fuels given in Kg?

[KerikBalm]

A little thing to watch out for is that not all fuel tanks are equal. The very small and 3.5m tanks mass more per fuel unit they contain than the others. The very small tanks are more expensive per fuel unit as well.

The very large tanks are fine IMO, given that you normally only use them when you haev a large payload, and thus the mass fraction doesn't change al that much (as tank weight in the lower stage is minor)... but the small ones... are quite bad, I loathe using anything smaller than the FL-T100.

And it wasn't noted, but the mass ratio of the tanks for Xenon is pretty bad too (and the propellant cost is obscene!)

[GoSlash27]

Ultimately it doesn't matter what the units are, so long as you understand how they scale to each other. But of course, the units *are* given. When in doubt, consult the wiki.

Finally, it would be helpful to know what you're trying to compute.

Best,

-Slashy

[MartGonzo]

calculations?

[Red Iron Crown]

calculations?

They're these things that make your rockets less explodey, I'm told.

[GoSlash27]

They're these things that make your rockets less explodey, I'm told.

Less failey, too

[tsotha]

They're these things that make your rockets less explodey, I'm told.

Or you could just use something like Kerbal Engineer.

[sedativechunk]

Like others aid, I recommend using the mod "Kerbal Flight Engineer", it's probably the most popular/used mod of KSP and it baffles me why it isn't an official part at this point. Flight engineer gives you very detailed stats on the mass of your ship, ISP in and out of atmosphere, your delta V in orbit around various bodies, and more. Great mod.

[DrMonte]

Like others aid, I recommend using the mod "Kerbal Flight Engineer", it's probably the most popular/used mod of KSP and it baffles me why it isn't an official part at this point. Flight engineer gives you very detailed stats on the mass of your ship, ISP in and out of atmosphere, your delta V in orbit around various bodies, and more. Great mod.

KER is not in the official game because it is not the Kerbal way of flying. It is not about precision flight engineering but about attach Jeb to the booster and Launch. That is why we have this cartoon world with real physics.

[Geschosskopf]

The game gives masses in tonnes

This is the very important thing to grok. Everybody on the forums says "tons" (=2000 pounds) but game masses are really tonnes (metric tons = 1000kg ~ 2200lb). It's a terrible habit we have so don't let it confuse you .

[Rusty6899]

I found it really confusing at first as "Power" was thrust in kN (can't remember whether this has changed but it probably has). I also had no idea about the rocket equation and was naively using Newtonian mechanics, which didn't help.

Mass is in tonnes (metric)

Thrust in kN

Isp in seconds

Considering that TRE only uses mass ratio, you only really need to know the Isp units to calculate delta-V.

[Daffs]

I right click on the part in the VAB/SPH, lots of stats.

Still not sure what they are for. I just pile stuff on top of each other and hit launch. Space is good, screams/explosions are bad. Simple!

[LethalDose]

Why aren't all fuels given in Kg?

because the game was written by 3d artists and coders, not scientists

[Red Iron Crown]

because the game was written by 3d artists and coders, not scientists

How does that make it easier for either group?

[r_rolo1]

It does not make it easier for anyone It simply explains the lack of consistence in the units: lack of familiarity with the subject + code made in chunks ....

[LethalDose]

It does not make it easier for anyone It simply explains the lack of consistence in the units: lack of familiarity with the subject + code made in chunks ....

This. How many times have we said "Its not the smart way to do it, but it's how Squad did it" on these forums?