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Why Do I Get So Much Hotter On Some Maps Than Others?


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#1 colsan

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Posted 27 September 2013 - 06:44 PM

So, I find myself in Mordor walking next to a volcano, and one alpha strike puts me into overheat mode; the next map, in a blizzard, it takes several shots just to get to the warning.

Why?

The volcano is 98 degrees C, and the Hoth lookalike planet is -85. That's ~370K and 185K, respectively and absolute. From previous mechwarrior games, overheating on a mech is 9000-10000 degrees, although in which system is never determined. It doesn't really matter, let's just call it Kelvin.

OK, down to brass tacks. The Carnot cycle (http://en.wikipedia....he_Carnot_cycle) describes heat transfer, specifically the rate of transfer, which is determined by the efficiency:

Posted Image

Let's assume a moderate heat load of 5000K. The efficiency on Hoth is then 1 - (185/5000) = .963, while the value for Mordor is 1 - (370/5000) = .926.

That's a 5% difference, and it's even worse at higher heat sink temps. At lower temps, yes, you will cool off a little faster in the cold, and of course sitting in water changes the value of the basic heat transfer equation, but hot water would be about as good as cold water.


Now, I know what you're thinking: "But Colonel Sanders, if what you are saying is true, then heat work work almost exactly the same on every map!" That's true, but I can't change the laws of physics; only game designers and Morgan Freeman can do that.

Well, I've got a solution for that, too! Put us on a barren moon, no atmosphere, but light and dark patches (or even different times of day?), so you will cool off in the shade but heat up in the light.

Another solution is an underwater map (I know there was at least one underwater mission in GBL I think? Can't remember atm), where it would be almost impossible to overheat.

Edited by colsan, 27 September 2013 - 06:45 PM.


#2 Koniving

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Posted 27 September 2013 - 06:48 PM

(<.<; Jazz had something that demonstrated why... plus the temperatures are just fluff the game doesn't really use them.)

On the water scenario you can find spots like that in the game right now. Here's one example.

#3 Greyrook

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Posted 27 September 2013 - 09:33 PM

shruuuuuuuuuuuuugmath. I'm pretty much the farthest thing from a physicist, but it looks like that equation has to do with liquids in a theoretical system (although I realise the contrarity of arguing that a theoretical physics system might not produce realistic numbers for a virtual system). I dunno, maybe it has to do with the way heat is exposed to the ambient atmosphere so it actually does matter, but it would seem to be logical to assume that even if the whole mech was acting as a direct heatsink, it would lose energy faster in a place that's 50% cooler. But, as I said, I don't have much of a head for physics and maybe at mechwarrior temperatures it wouldn't make a difference. Who knows? Not me, but I do know that adding variety to this gameplay element does at least help to characterize the maps, and that is generally a good thing.

#4 Scurry

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Posted 28 September 2013 - 01:22 AM

It's really not applicable, given the theoretical assumptions. Not to mention Carnot cycle equations only give you theoretical maximum efficiency. That 10000K figure, even if correct, isn't exposed directly to the air, plus we don't even know how heat sinks even work in BT. What's to say BT tech isn't much more sensitive to temperature changes? The rate of heat dissipation has to be considered by the temperature of heatsinks and the surface of the Mech - which is way lower than that, or the pilot would be dead. In fact, 9000-10000K is way hotter than even the surface of the Sun, and is twice the melting point of any material in existence today.

In short, expecting theoretical physics to apply in a game that does not specifically advertise itself as doing so is futile.

Still, some different maps with mechanics like that might be interesting. But don't rely on the physics to explain - for example, if the Carnot efficiency equation was applicable, using water at the same temperature as air would give you the exact same result - no difference in cooling.

Edited by Scurry, 28 September 2013 - 01:29 AM.


#5 scJazz

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Posted 28 September 2013 - 01:31 AM

Read the link in my Signature if you want to know about Maps and Heat

#6 colsan

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Posted 28 September 2013 - 06:59 AM

View PostScurry, on 28 September 2013 - 01:22 AM, said:

It's really not applicable, given the theoretical assumptions. Not to mention Carnot cycle equations only give you theoretical maximum efficiency.


Yes, properly this should be a Rankine cycle, but the critical figure is still the efficiency, which is temperature dependent.



View PostScurry, on 28 September 2013 - 01:22 AM, said:

That 10000K figure, even if correct, isn't exposed directly to the air


Um, it's not? Then what is the cold reservoir the heat is escaping to? If there is a medium (intermediate material), then its thermal properties would be the ones we would use, making that the heatsink.


View PostScurry, on 28 September 2013 - 01:22 AM, said:

, plus we don't even know how heat sinks even work in BT. What's to say BT tech isn't much more sensitive to temperature changes?


Because that would make them substantially worse than things we have had in real life for almost half a century?


View PostScurry, on 28 September 2013 - 01:22 AM, said:

The rate of heat dissipation has to be considered by the temperature of heatsinks and the surface of the Mech - which is way lower than that, or the pilot would be dead.


Why? We have people close to things that hot all the time. Arc welders, for example.


View PostScurry, on 28 September 2013 - 01:22 AM, said:

In fact, 9000-10000K is way hotter than even the surface of the Sun


That's meaningless, though; the surface is the coldest part of the Sun. In fact, the interior of Saturn is hotter than the surface of the Sun.


View PostScurry, on 28 September 2013 - 01:22 AM, said:

, and is twice the melting point of any material in existence today.


No, just higher than any material you are allowed to have; Starlite can handle that kind of temp, easily.



View PostScurry, on 28 September 2013 - 01:22 AM, said:

In short, expecting theoretical physics to apply in a game that does not specifically advertise itself as doing so is futile.



This isn't quantum physics, here, this is basic thermodynamics; Newton's law of cooling.



View PostScurry, on 28 September 2013 - 01:22 AM, said:

Still, some different maps with mechanics like that might be interesting. But don't rely on the physics to explain - for example, if the Carnot efficiency equation was applicable, using water at the same temperature as air would give you the exact same result - no difference in cooling.



/facepalm

No, water and air have completely different thermal characteristics; that is a different part of the equation. Please read the link before commenting.

Edited by colsan, 28 September 2013 - 07:08 AM.


#7 Nick Makiaveli

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Posted 28 September 2013 - 07:19 AM

View Postcolsan, on 28 September 2013 - 06:59 AM, said:



/facepalm

No, water and air have completely different thermal characteristics; that is a different part of the equation. Please read the link before commenting.


Not to be rude or anything, but maybe you should read up on the history of the game before /facepalming anyone. I'll wait. Done? Good.

Now do you get it? It's a game that was designed in the 80's to play off the whole Mecha thing. Not designed to teach math and the Laws of Thermodynamics.

MGs that weigh half a ton, can damage a mech, yet have less range than a modern day rifle?

Or in other words, do you really expect the devs to read this, say OMG the original designers failed to properly account for *words and stuff*!!! We have to shut down the servers while we fix this!!! Someone get colsan on the phone and offer him $42 million a year salary to help us fix this!!!!!!

Look, I'm happy that you've forgotten more about heat dissipation than I'm ever likely to learn, but that doesn't change the fact that
THIS
IS
BATTLETECH!!!!!!!

:D

#8 scJazz

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Posted 28 September 2013 - 07:25 AM

View PostNick Makiaveli, on 28 September 2013 - 07:19 AM, said:

*FUNNY STUFF*


LMAO!

#9 Arnold J Rimmer

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Posted 28 September 2013 - 07:26 AM

Heat in BT isn't going to work like thermal transfer efficiency in the real world. It boils down (heh) to if the map is 'hot', 'cold' or 'neutral'. If the map is 'hot', your heat capacity and cooling rate are lowered, on a 'cold' map they're increased, and on a 'neutral' map they will be as you see their values in the 'mechlab.

#10 Scurry

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Posted 28 September 2013 - 04:34 PM

View Postcolsan, on 28 September 2013 - 06:59 AM, said:

Um, it's not? Then what is the cold reservoir the heat is escaping to? If there is a medium (intermediate material), then its thermal properties would be the ones we would use, making that the heatsink.

Yes, it's the heatsink and the Battlemech.

Quote

Because that would make them substantially worse than things we have had in real life for almost half a century?

Hey, there are some things in BT are substantially worse than what we have in real life. Sensors and missiles, for example?

Quote

Why? We have people close to things that hot all the time. Arc welders, for example.

Because the rate at which the Mech loses heat is a function of the temperature difference of the Mech and its heatsinks to the surroundings. We'd have to do the math to compare the rate at which the Mech/heatsinks gain heat and the rate at which heatsinks lose heat, and find the equilibrium temperature - which is liable to be lethal - and I'm not going to waste time doing that.

Quote

That's meaningless, though; the surface is the coldest part of the Sun. In fact, the interior of Saturn is hotter than the surface of the Sun.

I'll concede the point.

Quote

No, just higher than any material you are allowed to have; Starlite can handle that kind of temp, easily.

If you postulate a fictional material that can mantain a magnetic bottle for fusion and withstand temperatures like that, anything's possible.

Quote

This isn't quantum physics, here, this is basic thermodynamics; Newton's law of cooling.

Yes, yes - and if all the laws of physics applied, Mechs would float on water.

Quote

/facepalm


No, water and air have completely different thermal characteristics; that is a different part of the equation. Please read the link before commenting.

Yes, the differences in entropy of the reservoirs, correct? Again, if you apply the Cournot assumptions, no difference.

But essentially, Battletech is unrealistic. It's a work of fiction. No point expecting it to be anything else.

#11 Krivvan

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Posted 29 September 2013 - 12:39 AM

This is the universe with rules about how cold mechs run in a vacuum. Larger caliber rounds travel less distance in Battletech too.

I'd cry if I wanted to have the game conform to reality.

#12 ColdPsyker1

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Posted 29 September 2013 - 07:46 AM

If you're wondering how he eats and breathes, and other science facts...
You shouldtell yourself "its just a show, I should really just relax".

#13 Spokes

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Posted 29 September 2013 - 08:00 AM

Not that this is "canon" or anything, but in Mechwarrior II Mercenaries one of the heat warning messages you get from the computer is "Warning: Internal temperature at 700 degrees Kelvin".

#14 C E Dwyer

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Posted 29 September 2013 - 08:09 AM

Applying pyhsics, to a fictional game, as like hitting your balls with a hamer, pointless and only going to cause you pain

#15 Appogee

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Posted 29 September 2013 - 08:18 AM

Because PGI.

#16 colsan

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Posted 29 September 2013 - 08:19 AM

View PostScurry, on 28 September 2013 - 04:34 PM, said:

Yes, it's the heatsink and the Battlemech.


So you are saying that the mech has a vacuum around it so the air doesn't touch?!



View PostScurry, on 28 September 2013 - 04:34 PM, said:

Hey, there are some things in BT are substantially worse than what we have in real life. Sensors and missiles, for example?



...and that's fair enough, civilization fell and is rising again, that's the level of technology; thermal properties of, say, ceramic (pottery!) are fairly standard, and while our ceramics are better than old ceramics, it's not by that big of a difference.



View PostScurry, on 28 September 2013 - 04:34 PM, said:

Because the rate at which the Mech loses heat is a function of the temperature difference of the Mech and its heatsinks to the surroundings. We'd have to do the math to compare the rate at which the Mech/heatsinks gain heat and the rate at which heatsinks lose heat, and find the equilibrium temperature - which is liable to be lethal - and I'm not going to waste time doing that.


Good for you. I did "waste time" doing the math, and it doesn't work. If you aren't going to crunch the numbers yourself, you have no argument.





View PostScurry, on 28 September 2013 - 04:34 PM, said:

If you postulate a fictional material that can mantain a magnetic bottle for fusion and withstand temperatures like that, anything's possible.


How about a nonfictional material that was invented in the early 1970s?

http://en.wikipedia.org/wiki/Starlite

Quote

Under tests Starlite was claimed to be able to withstand attack by a laser beam which could produce a temperature of 10,000 degrees Celsius ... Live demonstrations on Tomorrow's World and BBC Radio 4 showed that Starlite could keep an egg (coated in the material) raw, and cold enough to be picked up with a bare hand, even after five minutes of blowtorch attack.





View PostScurry, on 28 September 2013 - 04:34 PM, said:

Yes, yes - and if all the laws of physics applied, Mechs would float on water.


I want to see that math!



View PostScurry, on 28 September 2013 - 04:34 PM, said:

Yes, the differences in entropy of the reservoirs, correct? Again, if you apply the Cournot assumptions, no difference.


No; entirely wrong. So incorrect that I am having trouble coming up with words to describe it. In fact, in the future, when someone says something that is so completely wrong that it is going to take 5 times as long to correct as the initial statement, I'm just going to say that it is "Scurry."

That is the most Scurry statement I have ever read.




View PostScurry, on 28 September 2013 - 04:34 PM, said:

But essentially, Battletech is unrealistic. It's a work of fiction. No point expecting it to be anything else.


Then why don't we have unicorns? Wizards riding unicorns puking rainbows that melt our mechs?

If you throw away the basic laws of physics, then you open the door to whatever ridiculous thing comes up next.

#17 Koniving

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Posted 29 September 2013 - 08:22 AM

For those thinking we're supposed to be highly advanced in the 36th century...

There's several hundred thousand planets that this map and most of them don't actually account for as they usually list lore-mentioned inhabited planets and even then they fail to list them all.
Posted Image

Combine that even with faster than light travel, it takes weeks to months to get from system A to system B in the same space. This is a large reason combat is preferential to the ground.

Now consider that for the past 500 years, war has been virtually non-stop. Everyone, somewhere, was fighting some sort of war or another, and when one war stops another starts for a different set of factions. Meanwhile this elitist group called Comstar that controls all communications for all factions, intercepts info about any cool tech and horde it, destroying the factories and people that produce it so that no one else can have it.

In this future, over 60% of battlemechs are over 50 years old. A Good 20% are more than 100 years old. Some, older than that with maybe 15% or less being "brand new." The tech is falling apart. The machines are largely unstable. They are often in a state of disrepair (Which is why R&R tried to replicate but too harshly).

In the worst moments of the closed beta economy, it wasn't unusual to see an Atlas go into battle missing an arm. Once saw a Catapult begin with one leg, but since he had LRMs it didn't really matter so long as no one got to him.

Mechs are often handed down from generation to generation. "This is the mech my father used and his father before him, which he stole by climbing to the hatch when the pirate raided our farms. Shot him dead inside. Now it's used to protect ourselves."

If you have seen Firefly, that is a far more pleasant universe and even there, technology ranges from the wild west style flint-lock rifles and hand-pump water faucets, to the most impressive and superior tech you've ever seen.

Examples of farm equipment like the Harvester and the Harvester Ant are almost always covered in heavy rust, with barely functioning internal combustion engines (gasoline). You might have 10 on an entire planet, and sometimes they are more than 200 years old and still barely in service.

In MWO because there's nothing to govern our upgrades, we're running in the high end of the Star League tech, before all the wars that dwindled tech into nothingness. There's a reason Hunchbacks only went 64 kph. There's a reason an Atlas trucked along at 40 kph or less. There's a reason most builds only have standard heatsinks.

Far as cbill earnings, we're making 4 times more than the average mech jock would. We're paid like Solaris Arena fighters.

(Brought over from where I posted it in the wrong thread.)
For some idea of what it used to be like. November 2012. Atlas versus Atlas brawl begins after a short period of LRM bombing back when "An Atlas turned the tide of a battle." There's this one, just weeks before open beta, with 19 standard heatsinks. Repair and rearm, standard heatsinks and lack of the new tech XL engines (which have existed for less than 25 years) kept things pretty well in line. In this vid from July 2k12, a 90 kph Jenner was considered amazingly fast. When I retreat to the Dragon and the Catapult, watch their movements. Notice how different the game was, and how much closer the game was to the original Battletech that I described?

Another edit: In battletech lore, they literally use "Faxes" to transmit secure data. Yes. They slide a piece of paper down into a fax machine and press send after dialing a long security code / number. No. I'm not kidding. I'm dead serious.

Edited by Koniving, 29 September 2013 - 01:31 PM.


#18 colsan

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Posted 29 September 2013 - 08:47 AM

View PostSpokes, on 29 September 2013 - 08:00 AM, said:

Not that this is "canon" or anything, but in Mechwarrior II Mercenaries one of the heat warning messages you get from the computer is "Warning: Internal temperature at 700 degrees Kelvin".


I considered that, but in MW4, you get a heat readout that goes up to about 10000; this also makes more sense, since 700 K is about 800 Fahrenheit, which would barely melt lead, much less the graphite that the heatsinks are supposed to be made of.

#19 Nick Makiaveli

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Posted 29 September 2013 - 08:48 AM

View Postcolsan, on 29 September 2013 - 08:19 AM, said:


No; entirely wrong. So incorrect that I am having trouble coming up with words to describe it. In fact, in the future, when someone says something that is so completely wrong that it is going to take 5 times as long to correct as the initial statement, I'm just going to say that it is "Scurry."

That is the most Scurry statement I have ever read.






Then why don't we have unicorns? Wizards riding unicorns puking rainbows that melt our mechs?

If you throw away the basic laws of physics, then you open the door to whatever ridiculous thing comes up next.


Really? I was thinking "colsan" would work better. Physics /= Lore.

When I watch a movie and I see someone screw a silencer onto a revolver, I don't suddenly expect to see Merlin come out of a closet and gank the bad guy. Why? Because the movie is set in the real world, and somebody didn't do their homework. Doesn't mean they live in a alternate universe where magical silencers exist.

You seem to want to belittle people for lacking the knowledge you have, yet are you an expert on all things? Can you name a Assault class scout mech without googling it? Can you tell me if the following statement is true or false: A revolver is a pistol? Here's one closer to your expertise..why can you shoot a .38 round out of .357 even though it's a larger caliber, but cannot do the reverse even though it's smaller?

I'll shut up now as I suspect I am about to talk myself into a private conversation and I don't want to cause the mods that kind of grief.

#20 Duncan Longwood

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Posted 29 September 2013 - 09:26 AM

According to wikipedia, Magma can reach temps of 1600 celsius here on Earth. Pyroclastic flows, consisting of hot rock, ash, and gasses, have been recorded traveling as fast as 700km/h with temperatures as high as 1000 celsius. Pyroclastic eruptions have been observed on Jupiter's moon Io that travel at 1km/sec and reach heights of 500km into the atmosphere. The temperature given for the map must be the planet's temperature, because volcanoes are hot.



Basically, space volcanoes have lots of ways to overheat you, even if they don't have representations of every method in-game. Sometimes you just have to fudge it to make it fun.

Good Luck and Have Fun :lol:





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