290 replies to this topic

[Mercurial]

Geeze, what's next, you're going to tell me that giant robots that shoot lasers and missles are totally impractical for most combat situations and that a tank could essentially do most if not all of their combat roles, only better, while mounting more armor and weaponry due to a lack of need for all the support structure and space for bending parts?

[syngyne]

The answer is:

Giant robots are cool. Just roll with it.

[xVladx]

All the people talking about all these new light weight super alloys, than it could possibly weigh 100tons.

Realistically speaking, it would be much much heavier, and there shouldn't really be limits on exactly how much weight you could carry if you wanted to mount extra stuff, especially since most heavy and assualt mechs are quite similar in size.

Another thing that comes to mind is that the weaponary must be very weak in order for mechs to last so much in combat, A modern day shot from a tank or a guided missile, heck even an infantry carried AT missile will easily cripple a 100 ton mech.

A standard m1 tank weighing 60kg has an effective range of up to 4000m. Consider an Atlas ~16m high moving at 50km/hr it would take about 3.6 minutes to close within 1000m to the Abrams and fire on it. Assuming a loader at about 6 rounds/ minute the atlas would take 22 hits before it even comes into range! Not to mention that it only takes 1 or 2 hits to knock out a tank.

Now the point of all this is that the atlas realistically speaking is a very poor war machine unless it is very heavly armoured which means that it must be heavier than 100tons.

[gamesguy]

Stop trying to apply realism to BT. Giant robots are essentially magic, just roll with it.

[Kartr]

Skylarr, on 13 June 2012 - 05:57 PM, said:

So an M1 weighs 67.6 short tons. Since a Short ton is 2,000 pounds (907 kg) and a 1 Metric ton (1,000 kg) is 2,204 pounds. That means the Short ton is lighter than a Metric ton. That means according to you an M1 will float????

/facepalm

I want to make a "you're denser than an Atlas" joke, but I just don't have the heart to.

Tons and Tonnes are not the same as tonnes/m^3. The former are a measure of weight and mass respectively, while the later is a measure of density which is mass divided by volume. So if an Abrams has a sufficiently small volume (it does) then it will be more dense then water because its lower mass is divided by a smaller volume resulting in a higher density.

Solis Obscuri, on 13 June 2012 - 06:02 PM, said:

Assuming that an Atlas 'mech has the same volume as a giant shoebox big enough to comfortably fit over an Atlas 'mech is probably skewing your numbers.

Only if the 'Mech isn't sealed (water can flow through its hollow spaces easily), otherwise it gives us a nice lower limit for the density of an Atlas. Even if it is unsealed and lets water through, that volume I calculated gives us a pretty good idea of what the Atlas's volume is probably close to.

Solis Obscuri, on 13 June 2012 - 06:02 PM, said:

Also, the unfortunate fact about arguing points within a work of fiction is that you can't equate everything to our world, quite a few things have to be viewed based upon the "facts" presented within that fiction, and evaluated according to the consistency within that work. Trying to evaluate a fictional future combat vehicle (which has an elaborate fictional narrative explaining its design elements and technological genesis) by assuming it to be designed and built using past technologies of our world and timeline, as well as generally unscientific assumptions about sizes, weights, densities, and forces, is sort of like comparing apples to flying fish by assuming both to be made from minerals, and therefore just different types of rocks, and then asserting that based on first-hand knowledge of the rocks in your back yard neither can be edible.

Yes but somethings remain the same, constant. Things like the density of water and density = mass/volume. Those things, along with other constants allow us to evaluate future tech and get a rough idea if its plausible or not. In some cases you can do more than that if you have the knowledge of physics/engineering and copious amounts of time.

378m^3 is significantly greater than the 85m^3 an Atlas's total sealed volume would have to equal in order for it to be as dense as plastic, let alone get it to anywhere near as dense as metal, or worse armor. Which means that the density of an Atlas is still probably less than that of water even when you just take the sealed portions (assuming its not entirely sealed). None of this is "unscientific" as it is based on observation and a logical application of known scientific laws and methods. It points to a logical conclusion that the "tons" used on the equipment/vehicle/BattleMechs of BattleTech is a scale rather than a measure of mass.

Skylarr, on 13 June 2012 - 06:08 PM, said:

It is Sci-Fi. The creator is allowed to say that A&B fit into C.

No they're not, not unless they explain that they have some device that breaks the laws of physics and allows solid objects to fit inside each other. BattleTech doesn't have anything like that as far as I know of and any sort of "null space" technology is rather against the BattleTech design/ethos/whatever(can't think of the dang word).

[VampireBlah]

Think legs that aren't solid metal, but an aero bar made from titanium instead of chocolate. Actually 100 tons give some serious room for MASSIVE frames. Plus landing massive mechs, there legs ARE massive hydraulics, just the thing to land your 100 ton frame from a jump that suddenly weights 2000+ tons for the instant of deceleration.

[Solis Obscuri]

Kartr, on 13 June 2012 - 06:37 PM, said:

Yes but somethings remain the same, constant. Things like the density of water and density = mass/volume. Those things, along with other constants allow us to evaluate future tech and get a rough idea if its plausible or not. In some cases you can do more than that if you have the knowledge of physics/engineering and copious amounts of time.

378m^3 is significantly greater than the 85m^3 an Atlas's total sealed volume would have to equal in order for it to be as dense as plastic, let alone get it to anywhere near as dense as metal, or worse armor. Which means that the density of an Atlas is still probably less than that of water even when you just take the sealed portions (assuming its not entirely sealed). None of this is "unscientific" as it is based on observation and a logical application of known scientific laws and methods. It points to a logical conclusion that the "tons" used on the equipment/vehicle/BattleMechs of BattleTech is a scale rather than a measure of mass.

Water density varies with temperature and atmospheric pressure, which itself can vary depending on local gravity and atmospheric density... There's a point where you have too many unknowns to really solve the equation. By knowing that an Atlas is 13m tall and weighs 100 tons, I don't really have a the ability to solve for volume or density, because I have a measure of mass and a measure of distance, and some fluff stories telling me that almost everything is made from imaginary materials anyway. You've kind of worked yourself around backwards by trying to substitute in a bunch of things you know about modern, real-world vehicles and metals and some supposition from eyeballing some artwork and come to a conclusion that the original "facts" presented - that an Atlas is 13m tall and weighs 100 tons - cannot be correct. I agree that your conclusion is consistent with your fluff, but you had to create your own fluff to get there, which means you aren't really looking at a CBT Atlas, you're dealing with a giant war robot of your own design.

And if you want to know what really bugs me, it's how you can put ferro-fibrous armor or endo-steel crits wherever you want, instead of having to distribute them everywhere. And how do double-heat sinks fit inside the same engine, given that engine heat sinks aren't supposed to be normal heat sinks anyway? Wouldn't they over-cool the reactor and shut it down? And why is heat dissipation measured on a linear scale, anyway? Not to mention, shouldn't bigger engines occupy more space than smaller ones? And wouldn't they require bigger myomer bundles, spreading that weight around the 'mech? Same for the gyro, etc, etc.

Edited by Solis Obscuri, 13 June 2012 - 06:57 PM.

[FaustianQ]

Here is a thought Kartr - what would be the size roughly needed by an Atlas to weigh 100t and have a density ~15g/cm³ (less then slightly half good steel)?

I can't brain today, my think is broken, otherwise I'd do the math myself.

[Tyra]

Has anyone linked to this thread yet? It pretty much answers a lot of questions about armor and other things, and how mechs in general work, especially heat sinks and the like. (which are more like heat pumps than sinks)

Edited by Tyra, 13 June 2012 - 07:11 PM.

[Ketzktl]

You know, the weight of Mechs has never bothered me as much as having advanced machine guns that can't shoot more than 90 metres, but that is probably a topic for another thread.

[Synra]

There's a lot of interesting stuff in this topic, but allow me to take a stab at the topic.

I too have always thought the whole "ton" concept to be a weird aspect of battletech. As has been pointed out here, it especially doesn't make sense considering the size of the mechs. But it seems to me that when we say the atlas is a 100 ton mech, that doesn't mean the actual weight of the mech, but rather it's capacity. Like if you use a ladder, you should find a sticker on the side that says something like "do not exceed 300lbs on this ladder".

In the case of battlemechs, we are talking about the internal structure. The internal framework is what truely makes an atlas different from any other mech. All mechs to varying degree are using the same weapons, armor, engines, etc. Those aren't what make a mech unique. What makes an Atlas the big tall round headed monster that it is, is the robotic internal contstruction of it. And like the ladder mentioned previously, that robotic structure is designed to support a load.

So, your Atlas frame is deisgned to carry a maximum load of 100tons of equipment bolted onto it. Thats weapons, ammo, heatsinks, armor, engine, reactor, gyro. And of course all the other little systems that battletech players don't normally think about like electrical, hydrolics, computer systems, communications, radar, lights, air handling for the cockpit, the pilot and his controls, and probably more stuff I can't think of at the moment.

With all of that said, the actual robotic internal structure shouldn't be taken into account when you say that the atlas is 100 ton. Because it's supporting that weight, not a part of it. Again, lets look at ladders. I grabbed a link to a ladder on amazon.com. This ladder is rated for 375lbs, but weighs 34lbs. That sounds like a great ratio, but I point out these specs because the ladder doesn't have moving parts like a mech does. The ladder has the shape and design that it does in order to provide the maximum weight capacity for minimum ladder weight. A Mech frame however has many joints for walking and combat purposes. That will reduce the structural strength of it, requiring even stronger / thicker materials and mechanical parts. The actual framework of an Atlas is likely pretty heavy.

This also explains why the maximum mech weight is 100 tons, and why there are so few 100 tonners. It's a product of engineering. Producing a frame that can hold 100 tons and still have all the mobility a mech requires would mean some pretty specific engineering work both in the structural design and materials used. 100 tons is simply the best they were ever able to pull off. Beyond that, they simply don't have materials strong enough to produce a stronger frame. Engine limitations is also likely a big factor here, like in the tank that was talked about in a previous post here.

I am sure someone would like to argue "Internal structure is included in the 100 tons!". But this is the most logical explanation behind mech weight. Anything else simply doesn't make any sense. All mechs are far too large to actually fall in the 30 - 100 ton range. Even a light mech like a Jenner should probably be close to 100 actual tons, given it's size.

[Kartr]

Solis Obscuri, on 13 June 2012 - 06:53 PM, said:

Water density varies with temperature and atmospheric pressure, which itself can vary depending on local gravity and atmospheric density... There's a point where you have too many unknowns to really solve the equation. By knowing that an Atlas is 13m tall and weighs 100 tons, I don't really have a the ability to solve for volume or density, because I have a measure of mass and a measure of distance, and some fluff stories telling me that almost everything is made from imaginary materials anyway. You've kind of worked yourself around backwards by trying to substitute in a bunch of things you know about modern, real-world vehicles and metals and some supposition from eyeballing some artwork and come to a conclusion that the original "facts" presented - that an Atlas is 13m tall and weighs 100 tons - cannot be correct. I agree that your conclusion is consistent with your fluff, but you had to create your own fluff to get there, which means you aren't really looking at a CBT Atlas, you're dealing with a giant war robot of your own design.

Well I have three distance measures if I use the artwork, so I'd argue that I'm using their fluff. The density of the Atlas is completely independent of the materials used as we're supposedly given its mass. So using their stated height, mass and art I can establish a few things without creating my own fluff. Things like the rough volume (based on their fluff) is 378m^3, I can determine the necessary volume needed to make a 100 ton 'Mech have roughly the density of modern plastics (85m^3) and I can determine that on Earth at sea level under standard temperature and pressure, an Atlas (assuming fully sealed) is just over a quarter the density of the sea water. All of that without making up my own fluff, without having to know the properties of any of the materials used in BattleMech construction.

Second read through I see you mentioned I'm basing it off of artwork, which yeah that's a weak spot since each canon image of the Atlas is going to have slightly different dimensions. However they should all be fairly close and considering how much less dense than my calculations make it, no Atlas image should be enough to bring it up to water density (@STP).

If it is so drastically off and given the things you point out below, doesn't it make more sense to simply say that "tonnage" is just a scale and not an actual measurement of weight? Simplest explanation and covers all the wildly varying densities you'll get from all the other 'Mechs and different artwork.

Solis Obscuri, on 13 June 2012 - 06:53 PM, said:

And if you want to know what really bugs me, it's how you can put ferro-fibrous armor or endo-steel crits wherever you want, instead of having to distribute them everywhere. And how do double-heat sinks fit inside the same engine, given that engine heat sinks aren't supposed to be normal heat sinks anyway? Wouldn't they over-cool the reactor and shut it down? And why is heat dissipation measured on a linear scale, anyway? Not to mention, shouldn't bigger engines occupy more space than smaller ones? And wouldn't they require bigger myomer bundles, spreading that weight around the 'mech? Same for the gyro, etc, etc.

Heh see its all nonsense designed to make a better game! That's my whole point!! None of it (even the masses) was designed to be plausible or make sense except in the broadest of possible ways and only if you don't think about it. Its all just a little bit of handwavium designed to make things that help the game feel right.

[0siris]

I saw an atlas once and it said to just ride and pew.

[Kartr]

FaustianQ, on 13 June 2012 - 07:01 PM, said:

Here is a thought Kartr - what would be the size roughly needed by an Atlas to weigh 100t and have a density ~15g/cm³ (less then slightly half good steel)?

I can't brain today, my think is broken, otherwise I'd do the math myself.

umm well lets see, first I changed it to be 0.000015g/m^3, then I had to change 0.000015g into tonnes which gets us (1.5x10^-8 tonnes)/m^3. Then I divide 100 tonnes by that which should get us the cubic meters needed, and if I did everything correctly it would require a volume of 6.7 billion m^3. O.o Yeah BattleMechs are impossible.

[Birddog FAC]

Frostiken, on 13 June 2012 - 02:42 PM, said:

What I don't understand is how mechs function on worlds with more than 1g. Is there anything in the lore that ever describes a high-gravity world that basically causes heavier mechs to crumple under their own weight?

Also, jumpjets. Jumpjets put mechs under a lot of acceleration - I honestly can't picture a heavyweight mech activating the jumpjets and dealing with the high G-forces from acceleration and landing without breaking things.

Under a mere 2g, which you'd experience after simply falling 20 meters, your Archer weighs 140 tons o_O

Naturally there'd be some wiggle-room in the 'maximum weight' of a frame just to prevent this, but realistically why are mechs limited to x tons of weapons then? Even aircraft can overload themselves but it means they can't pull as many Gs, so wouldn't a mech on a high-gravity world have to go out missing a lot of weapons, and shouldn't they be able to overload the frame on a low-gravity world?

The mind boggles.

its as you said this allows for wiggle room and is also depended on available critical spaces... also all mech armor is internal ... the catapults missle racks are actualy its arms. so they have to limit it. also more weapons mean more heat more heat means more heat sinks more heat sinks mean less crital space to place weapons. on a high g world the mechs do move slower and the jump jets are less effective.. because they are lifting 140tons. and so on .. on a lighter world mechs are also slower as they bound.. not safe for somethign stabalized by a gyro. (could throw off the calibration) but the jump jets are much more effective. not that in reality a mech could go faster in low gs its just not a practice as it messes with stability.. and mass is still mass 100 tons is 20,000 lbs wich equals 640,000 newtons if i remeber correctly and mass is weight in zero g so no mater what its still 640,000 newtons falling or slideing along a surface doing aproximately the same amount of damage to mech. tho the mech may slide further to do the same amount of damage. this effect would be less on a human as human tissues have elastic propertys allowing them to absorb impact while sheets of armor dont they bend, shear, ripm crack , and splinter with our without gravity on impact. i fell like i left something out if so sorry. if im being to **** in the response please excuse that too

oh and short answer is that a atalas is the tallest mech at around 9 or 10 meter tall the shortest mechs stand at 3.5 meters... like the puma or panther. and the commando is 5 meters at 25 tons... just thinner arms and legs

[EDMW CSN]

The Atlas internal structure only weighs 10 tons.
With that mere 10 tons, it can carry a 19 ton reactor, 19 tons of armor, 10 extra heatsinks (10 tons) and 36 tons of weapons.

The remaining 6 goes to gyro, cockpit, life support and sensors.
That is some mighty fine engineering there.

[Havyek]

People are aware that this is FICTION, right?

Make believe?

Pretend?

Not real?


Any of this getting through?

[Jdee]

Rofl I got a good laugh see the Weight Watchers pic. If I remember right in Mechwarrior they had a mission or two where you were in zero grav where you could move faster and higher grav where you could not do the max speed that you were capable of. That being said also if I remember right some of the Battlemechs actually had a second seat especially the mighty Battlemaster *sigh not in game yet (read from book don't ask which one be many years ago).

[Kiriko]

FaustianQ, on 13 June 2012 - 07:01 PM, said:

Here is a thought Kartr - what would be the size roughly needed by an Atlas to weigh 100t and have a density ~15g/cm³ (less then slightly half good steel)?
I can't brain today, my think is broken, otherwise I'd do the math myself.

15g/cm3 means that 1m3 of that material is 15t, so 15t/m3. (http://www.smartconv...calculator.aspx)
So a 100t cube of material, would be 6.67m3
(edit, got my math wrong)

According to this (http://hypertextbook...utherland.shtml) delicious steel is more like 8g/cm3 (or 8t/m3).
So it would be 12.5m3 of steel in 100t.

Edited by Kiriko, 13 June 2012 - 08:08 PM.

[Deathjester]

Kartr, on 13 June 2012 - 07:33 PM, said:

umm well lets see, first I changed it to be 0.000015g/m^3, then I had to change 0.000015g into tonnes which gets us (1.5x10^-8 tonnes)/m^3. Then I divide 100 tonnes by that which should get us the cubic meters needed, and if I did everything correctly it would require a volume of 6.7 billion m^3. O.o Yeah BattleMechs are impossible.

I think you might have gone the wrong way with the unit conversion.
If 1cm^3 of water is 1g and 1cm^3 of steel is 15g, then if a 1m^3 of water is a ton then 1m^3 of steel is 15 tons.
Therefore density = 15g/cm^3 = 15t/m^3
As mass divided by density equals volume:
100t/15t/m^3 = 6.67m^3

BDU Havoc, on 13 June 2012 - 07:40 PM, said:

People are aware that this is FICTION, right?

Make believe?

Pretend?

Not real?


Any of this getting through?

WHAT?! *looks out window, sees no mechs* We've been lied to people! Mechs AREN'T real!

Yes, we understand. We're also enjoying discussing the finer engineering points of a purely hypothetical situation, feel free to join in if you want.

Edited by Deathjester, 13 June 2012 - 08:00 PM.