Difference between revisions of "User talk:Elembis"

Revision as of 04:39, 18 October 2012

Good job adding that gallery section on the Minmus page, we should probably do that for every celestial. --Craigmt1 (talk) 19:57, 28 September 2012 (UTC)

Imagination Cookie for you!

Well done! you where the first person to correct an inevitable mistake from my mass editing of the version sections for all the parts! I here by present you an Imagination Cookie. This is perhaps the most amazing cookie ever imagined, it is rather large compared to normal cookies, but not to the extreme that you can not take it with you where ever you go, and you will want to do this, for every bite tastes of what ever foodly desires you might have. Don't worry about wasting this bad boy though, for each bite you take will slowly regrow, so your cookie will never run out, as long as you can refrain from eating it all in one go. You may fear that living of cookie will be bad for you, but this beauty has your back, for each bite is perfectly balanced nutritionally. You could even take your cookie to Africa, and feed the hungry, but how would you get their? Simple, just get your self a rug, a sprinkle some crumbs and pow! You now have your very own cookie powered flying carpet, I have been told that it can also power cat's, but I have yet to ascertain what exactly this means. Take care good sir! Thecoshman (talk) 09:16, 2 October 2012 (UTC)

planetboxrow

hi, do you know how to add the planetboxrow to Planetbox 2.0? I've been trying to do that but it has been screwing up. It just ends up removing half the page. I am not really fluent in programming, so it is probably me just making a stupid mistake. But if you could help me, i would be forever thankful!--Azivegu (talk) 14:30, 16 October 2012 (UTC)

I made a change to Planetbox 2.0 showing an example of how to use PlanetBoxRow. Note that the table syntax for a row occurs within that template, so using the template means you can get rid of "|-", etc. for the row it appears on. Take a look at http://kspwiki.nexisonline.net/w/index.php?title=Template%3APlanetbox_2.0&diff=6605&oldid=6598 and let me know if that helps. =) — Elembis (talk) 15:29, 16 October 2012 (UTC)

Units of measure

Hi Elembis,

I am trying to be very careful only to post accurate information so any input is welcome.

I am trying to find where mass is referred to as kg in-game but I can't seem to.

My logic for converting kg to metric tons is as follows

While units are not specifically labeled in-game, a bit of logic can quickly determine that thrust is measured in kilonewtons (kN) and mass in metric tons (t). For example, if measured in kilograms(kg), a "9 kg" Rockomax X200-16 Fuel Tank on Kerbin, having a surface gravity of 9.81 m/s2 (According to the wiki page), would be roughly the size of a 48 oz coffee tin and only hold about 1.5 L of fuel. If measured in metric tons, a 9 t Rockomax X200-16 Fuel Tank under the same gravity would be about 0.67 m tall and 2 m in diameter, easily capable of holding the advertised 1600 L of fuel. Only a rocket engine with a thrust around 100 kN, let alone 100 N, could have any chance to lift a 9 t fuel tank. Also, on a side note, Kerbals appear to be about 0.75 m tall :)

Please let me know if this seems reasonable as my calculations may be incorrect. A good number of forum pages and even MechJeb agree that kN and tons are more inline with the scale (meters) of the rockets.

Thanks!

--Jlmr (talk) 01:51, 18 October 2012 (UTC)

Thanks for bringing this up! And yeah, now that I think about it, I don't know if kg is actually specified in-game. I did see your explanation for using metric tons and kN instead of kilograms and N. In any case, we need to use the same mass units everywhere, for parts as well as for planets... — Elembis (talk) 02:20, 18 October 2012 (UTC)

Take a look at this handy calculator, http://www.smartconversion.com/unit_calculation/Mass_calculator.aspx. It looks like the mass of Kerbin in kg is spot on. We could use metric tons (tonnes) for planets as well to save some space on the page. --Jlmr (talk) 02:27, 18 October 2012 (UTC)

For the planets, one easy way of proving that their masses are specified in kg and not tons is to calculate the orbital velocity needed for, say, a circular Kerbin orbit 100 km above the surface. With kilograms, I calculate a period of 845.92 s for a velocity of 2971 m/s. With metric tons, I calculate a period of 26.75 s for a velocity of 93,953 m/s. The numbers that match gameplay are clearly the first ones. =) — Elembis (talk) 03:00, 18 October 2012 (UTC)

I agree with you there, I was just suggesting a conversion to tons to match the parts list, it really is not necessary though. It's probably simpler to leave planets in kg as that is what most real world measurements of planetoids are in. It's odd that you get a different number when calculating period though. You should get the same answer albeit having to do a unit conversion 1ton/1000kg. --Jlmr (talk) 03:11, 18 October 2012 (UTC)

To be clear, when I say planets' masses "are specified in kg and not tons", I'm referring to the values returned from the CelestialBody.Mass() function, whose documentation specifies no units. Similarly, I believe the part masses displayed in-game correspond to those in Part.mass, which one can only assume is specified in the same arbitrary mass units as a planet's mass. Would you agree that these arbitrary mass units are actually in units of kg, based on the orbit calculation above? — Elembis (talk) 03:18, 18 October 2012 (UTC)

AH! Now I see what you are saying and I agree with you there about planet mass. However, the game engine probably converts kg to tons for the UI so we don't have huge numbers displayed. Example: This fuel tank weighs 20000 kg, instead it shows 20 t to save UI space. --Jlmr (talk) 03:29, 18 October 2012 (UTC)

The game never says "kg", "t", "kN", or "N" anywhere, this is basically my argument:

1. CelestialBody.Mass() is specified in arbitrary mass units.
2. Part.mass is specified in arbitrary mass units.
3. Premise: Part and CelestialBody use the same arbitrary mass units. Even if they don't, we should be consistent on the wiki wherever possible, and this is an area where being consistent is really, really easy. The fact that kilograms and newtons are SI units is a bonus.
4. CelestialBody's arbitrary mass units are kilograms (see orbital calculation above).
5. Therefore, part masses are kilograms as well.

I recommend that you don't change "kg" to "t" and "N" to "kN" on every page on the wiki until more people have had a chance to weigh in on this. =) — Elembis (talk) 03:45, 18 October 2012 (UTC)

I understand what you are saying. And I agree completely that the game engine uses kg in the background. However, I am trying to stay consistent with the units used in the game's user interface and part.cfg which is arguably what most people using the wiki will be familiar with. If we do decide to use kg and N we will need to multiply the values for mass and thrust on each page by 1000 to give correct/usable information with respect to the physics of the game. --Jlmr (talk) 03:57, 18 October 2012 (UTC)

I don't think I understand your last sentence -- why can't we just say an aerospike weighs 1 kg (since its mass is "1" in its part.cfg and in-game in the VAB and SPH, and since an arbitrary mass unit (amu) is apparently 1 kg)? Why would we have to multiply it by 1000 on the wiki? — Elembis (talk) 04:13, 18 October 2012 (UTC)

It is because, similar to your calculations with the planet. Using kg for parts makes no sense. For example, we know that the Mk1-2 Command Pod weighs 4 units. We also know that the game uses meters for units of distance. The command pod is roughly 2 meters in height and 4 meters in diameter. Calculating it's volume gives us about 8.38 cubic meters. Knowing that, we can calculate it's density using kg which comes out to be about 0.48 kg / cubic meter. The problem is that an object with a density of 0.48 kg / cubic meter would be about 3 times less dense than air and would probably float away like a helium balloon! However if we use tonnes as our unit to calculate density, we get a density of 238.732414637842 kilogram / cubic meter suggesting that the capsule might be made of a light metal like aluminum (this is very very close to the density of the actual Apollo Command Module). Likewise with the aerospike, it makes more sense within the physics of the game for it to weigh 1 tonne rather than 1 kg... Unless Kerbal's have discovered a super strong styrofoam to make engines from. :D Hopefully that cleared up my thinking. --Jlmr (talk) 04:33, 18 October 2012 (UTC)

Yeah, I understand the density argument, I just think it's more important to use SI units and follow the game in using the same mass units for ships and planets. It's a matter of personal preference, and for that reason I think we should let other people weigh in on it. I made a section on the main talk page for that purpose: Talk:Main Page#Units of measurement for part masses and engine thrust — Elembis (talk) 04:39, 18 October 2012 (UTC)