290 replies to this topic

[Hyperius]

RedDragon, on 16 June 2012 - 02:36 AM, said:

Good thing then that we can explain it, doing our maths right

I'll have to trust you guys on that since I really suck at math

[SuperDude431]

Science fiction is a form of fantastical literature. Science fiction is possible because it is based on facts, even if it isn’t likely. For example science fiction could be robots, fifth dimension or alien invasions. Fantasy is things that aren’t scientifically possible, like talking animals, or some one who is immortal.

[TKG]

Deathjester, on 13 June 2012 - 04:48 PM, said:

Limbs in mechs are driven by Myomer bundles, an artificial musculature system, it's not like they're full of gears and cogs to get gunked up. If a 4WD can handle a bit of water I'm sure that a Battlemech can as well.

Dunno if this has been answered or not but you really need to look at the mech cutaway art The mechs limbs are not exclusively powered by mynomar, there are infact hydraulics, actuators and electric motors. This fact has been verified by miriad TRO sources and supported by varied sourcebooks and errata. Prime example, the blackjack, Stone rhino and suner's entries all reference actuators or hydraulics, which would power some form of limb motion or a joint in a limb*.

*in two of three cases a leg but still.

[Fred Sampson]

I'm not sure if the question has been approached from this angle yet, but consider the tonnage and overall size of an M1 Abrams tank.

According to Wikipedia, an Abrams hull is just shy of 8 meters in its longest dimension, while the vehicle weighs around 60 metric tons. Dividing the weight by its long dimension gives you 7.5 tons per meter of length. An Atlas, being 13 meters tall and weighing 100 tons, would be around 7.8 tons per meter of its longest dimension. This doesn't account for open space in the shape of an Atlas, with room between the legs for example and (probably) less thickness from front to back of the Atlas versus top to bottom of an Abrams.

Overall the impression given is that a mech would be more dense than a current technology tank, which would be logical considering the previously mentioned fighting compartments needed by tanks.

Granted, images of mechs often make them look significantly larger than an Abrams tank turned vertically, but that's just artistic license and inconsistent with the heights provided anyway.

Edited by Fred Sampson, 17 June 2012 - 12:04 AM.

[Colonel Bogey]

Well all I can say is that I think "an" Atlas weighs 100 tons because it was designed to be thus. If it was to weigh more would that not betray the design, and lead to many problems. Components that are rated for the mech, being as it is 100 tons, might not be able to with stand the pressures and strains created by additional weight let alone all out combat. Though the components would seem to be sturdy enough to take the weight of the mech, adding additional weight when not changing the current design would be foolish. Tests would have to be run, components designed, and money spent.
Economically speaking it is not a viable option. The mech already, I would imagine, cost a substantial amount of credits or what ever. Having said parts fail or become damaged would cost you an arm and a leg due to the fact that they would not be considered stock. This would be my understanding of why "an" Atlas would not weigh more than 100 tons.

[trycksh0t]

EDMW CSN, on 13 June 2012 - 07:38 PM, said:

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.

Not really. Since BattleMechs are relatively based on the human form, it's not that hard to believe. The average human skeleton accounts for 15% of the total body weight. If someone weighs 200 lbs, their skeleton would weigh 30 lbs and be supporting 170 lbs, or a smidge over 5.5 times it's own weight constantly. It is capable of supporting a great deal more than that, otherwise we'd never be able to lift or carry anything without our bones breaking. The material BattleMech internal structures are constructed out of are, I would assume, considerably stronger than human bone, so the Atlas' 10-tons of structural support shouldn't have a problem supporting 90-tons of material or more.

Edited by trycksh0t, 17 June 2012 - 02:28 AM.

[Deathjester]

TKG, on 16 June 2012 - 11:36 PM, said:

Dunno if this has been answered or not but you really need to look at the mech cutaway art The mechs limbs are not exclusively powered by mynomar, there are infact hydraulics, actuators and electric motors. This fact has been verified by miriad TRO sources and supported by varied sourcebooks and errata. Prime example, the blackjack, Stone rhino and suner's entries all reference actuators or hydraulics, which would power some form of limb motion or a joint in a limb*.

*in two of three cases a leg but still.

The issue being discussed was not the exact method in which motive power was supplied but the way in which it could be exposed to the environment without compromising it's function. Gears and cogs were given as examples of mechanical linkages that would be adversely affected by water and foreign objects, whereas myomer, hydraulics, actuators, electric motors and the like can all be built as sealed units, preventing water and foreign objects from entering.

I've seen plenty of cutaways, thankyou.

[Gun Bear]

Boymonkey, on 13 June 2012 - 02:37 PM, said:

Now I can't find any info on how tall an Atlas is but looking at the videos etc I reckon they are pretty big so it got me thinking that an atlas should weigh more than 100 tons, I mean if you look at tanks for example a Tiger that weighs 56 tons and would look small next to a Atlas so surely they should weigh much much more.
Sorry for the boring topic it's just grating on my mind Oh and typing this passes a few min's to get me closer to playing

Since they are using metric measurements in the game the weight of an Atlas is 100 tons in mass measurements, a metric ton is about 2204.5 pounds. So the weight of an Atlas weighs about 111 tons.

[LeTigre]

I have alwasy considered the measurement more in line with the desingations for military transport. The "deuce and a half" max authorized payload is 2.5 tons. Similar with the "5 tons" of my gulf war days and the "10 ton" HMMTs. Take this into the battlemech universe and it is the maximum total of all things the mech must carry including its own engine, armor, armaments and fetures, but not including the cockpit, hardpoints and basic structure on which everything is mounted. Just my take I know, but it made sense to me...

[Gun Bear]

LeTigre, on 17 June 2012 - 06:57 AM, said:

I have alwasy considered the measurement more in line with the desingations for military transport. The "deuce and a half" max authorized payload is 2.5 tons. Similar with the "5 tons" of my gulf war days and the "10 ton" HMMTs. Take this into the battlemech universe and it is the maximum total of all things the mech must carry including its own engine, armor, armaments and fetures, but not including the cockpit, hardpoints and basic structure on which everything is mounted. Just my take I know, but it made sense to me...

This is also a possible explanation. I would Hazard that the King Crab is actually heavier than an Atlas but they carry the same max load.

[Major Bill Curtis]

RedDragon, on 15 June 2012 - 04:07 AM, said:

Thanks. Finally some right numbers.

I don't like it how guys like Kartr create such nonsense as floating mechs with absurd formulars:



That would be the volume for an Atlas with the proportions of a box with the sizes 14mx5mx5m. That's like estimating the volume of a human by calculating with a box of 1,8x0,65x0,65m. That would be a VERY broad shouldered and VERY VERY fat guy. And by 100 kilos such a person would indeed float, even if you put a weight belt on him.
A humanoid mech (or any humanoid shape for that matter) has MUCH less volume and therefore Major Bill Curtis' numbers are way better estimates.

Edit: You don't even have to calculate with density etc.
Simple way to visualize it:
The human body has approx. the density of water.
A normal man of 1,8m weights let's say 80kg. If you take his size x10, he is 18m tall and has the weight of 80x10³kg=80.000kg=80 tons. But he has still approx. the density of water, i.e. he has a near neutral buoyancy. A 14m mech with 100 tons is a lot smaller and weights a lot more, therefore its density would be higher than that of the human. Ergo it would sink. Q.e.d.

HI Reddragon.

I intentionally kept the human weight high (100 kg) for two reasons: 1) ease of calculation (not for me but for others); 2) 'mechs do appear to be a bit bulkier than people.

If you had a truly anthropomorphic 'mech of 20 tons at 10 meters in height, based on an 80kg, 1.8m human, its mean density would be ~1.48 g/cm3; at 14 meters and 100 tons, it's a whopping ~2.67 g/cm3. In the former case, that's a mean density (including air spaces) of Calcium, in the latter, it's hovering around Aluminum or Strontium (i.e. considerably denser than aircraft).

As dense as a modern tank? No. But a 14-meter statue of an average human male (1.8m/80kg) made of solid aluminum would weigh 100 tonnes.

Only bad math will make 100 tonnes of solid aluminum float.

For those of you keeping score, aluminum is roughly 1/3 of the density of steel, so you could also make a hollow 14-meter statue of a human that weighs 100 tons out of steel. 2/3 of the volume of the statue would be air, but the other 1/3 of the volume would be solid steel. That is a lot of steel. In some places the statue would have steel over 30cm thick. Keep in mind there'd be nothing inside the statue, just air, but this is the other extreme.

Also keep in mind that density is good in armor, but it isn't everything: copper is denser than steel; silver is denser than steel; lead is denser; gold is nearly 3-times as dense; tin (yes, tin) is usually within 5% of the density of steel. No one wants tin armor.

Finally, since 'mechs use armor that works differently from most contemporary armors --- it's ablative --- it is not a stretch to imagine that 'mech weapons might penetrate the armors we're used to quite easily --- if that were the case, 19 tons of steel wouldn't be enough to protect a 100-ton 'mech. Instead, devising a highly advanced lightweight low-density alloy that fractured externally without spalling would be one solution. In that case, the armor might fracture better in certain, more complex shapes (like a 'mech), than in other, less complex shapes (like a tank). 'Mechs are more resilient than tanks (in TT) because they have more armor locations, which rationalizes this

Are there physics reasons for this? There could be, given the right materials: have a look at area rule, in aerodynamics, as a rather odd phenomenon. Why isn't your jet as sleek as you think it should be? Area Rule. Lots of apparently common-sense explanations don't work in the real world. Developing a complex-fracture ablative armor to deal with weapons that go through very heavy weights of hard and dense ceramics and metals is a reasonable rationalization of game rules.

Ceramic, by the way, is only slightly denser than aluminum.

Going Sci-Fantasy there at the end, but for us, it still makes a good game.

Edited by Major Bill Curtis, 17 June 2012 - 08:28 AM.

[Kosomok]

Armor effectiveness is not necessarily related to density, particularly when that armor is optimized to be effective against a variety of threats.

An ablative ceramic would be far more effective against laser fire than DU would be--and it is FAR less dense. Spaced armor is far more effective against HEAT warheads than a solid plate of steel and reactive armor works against both HEAT and AP weapons. Composite armor (such as Chobham) represents a compromise/combination that is effective against both AP and HEAT attacks.

Composite armors tend to be bulky (because of the layering) and expensive (cost of materials and production) and so they do not get used on all surfaces (usually only frontal surfaces).

With advances in material science, I would expect BT armor to be lighter (per standard unit of protection) than contemporary composites. I would not expect to see significant differences between contemporary AP weapons and BT weapons, other than increase in muzzle velocity... energy output from ballistics is essentially limited by the ability of the chassis to absorb the attendant recoil forces... so mech defences would likely be slightly better against ballistic weaponry on a pound for pound basis than current defences as the armor improved more than the weapons did.

I would expect that HEAT weapons would increase in effectiveness more than AP because of advances in explosives.

Lasers are difficult to extrapolate as the power requirements are high and we have a long way to go before portable weaponry of that type is meaningfully possible.

[Major Bill Curtis]

LeTigre, on 17 June 2012 - 06:57 AM, said:

I have alwasy considered the measurement more in line with the desingations for military transport. The "deuce and a half" max authorized payload is 2.5 tons. Similar with the "5 tons" of my gulf war days and the "10 ton" HMMTs. Take this into the battlemech universe and it is the maximum total of all things the mech must carry including its own engine, armor, armaments and fetures, but not including the cockpit, hardpoints and basic structure on which everything is mounted. Just my take I know, but it made sense to me...

I think this is as good an explanation as any calculation. Even in civilian life, half-ton and three-quarter-ton pickup trucks are relative designations that have nothing to do with vehicle weight.

[Crankey]

Hey just home from fathers day celebration, several free beers under my belt.

I'm simply too disorientated to even attempt to know why an Atlas should weigh more than 100 tons with the possible explanation that we mere Earth humans are in comparison to the mech warrior pilots stand only 2 feet tall and as such, the mech warrior worlds weight system must therefore be inflated by at least 300% !

There, Now I've sorted that one back to my Pending button

[grimzod]

Boymonkey, on 13 June 2012 - 02:37 PM, said:

Now I can't find any info on how tall an Atlas is but looking at the videos etc I reckon they are pretty big so it got me thinking that an atlas should weigh more than 100 tons, I mean if you look at tanks for example a Tiger that weighs 56 tons and would look small next to a Atlas so surely they should weigh much much more.
Sorry for the boring topic it's just grating on my mind Oh and typing this passes a few min's to get me closer to playing

Electrically motivated myomer bundles (hip, shoulder, hand and foot crits) powered by the fusion engine are the main motive force of the mechs. Atlas is 13 meters high. Most mechs are not solid but a superstructure filled with their internal systems (ammo feed, storage, sensors and fusion engine, life support and weapons) then encased in a thin ablative layer of armor panels.

Jump jets divert fusion engine exhaust through ports to allow ammech to leap into the air. As well as jumping up the jets allow for maneuvering during the jump and decellerAtion so a Non lethal landing is possible.

Edited by grimzod, 17 June 2012 - 09:02 AM.

[Artifice]

I've often pondered this point. As has been mentioned, you've just gotta put most of it into the 'fancy wancy science fiction' category.

Don't get me wrong, I'm a huge fan. HUGE FAN!

The huge BUT! is that it's completely ridiculous to assume that in 1000 years we will be fighting for planetary supremacy using 20 - 60 foot tall walking tanks. Other fans that I've spoken to agree - This is a non viable situation. Meditate on that for a moment. Your logic has now been suspended. Please proceed to play now.

p.s. Don't get me started on the max range for a freaking millenium-th generation Gauss Rifle or rail gun. Currently 3.5 tonnes gets you 6ft/8m accuracy. Six Feet over Eight Miles!

Edited by Artifice, 17 June 2012 - 09:03 AM.

[Firelizard]

LeTigre, on 17 June 2012 - 06:57 AM, said:

I have alwasy considered the measurement more in line with the desingations for military transport. The "deuce and a half" max authorized payload is 2.5 tons. Similar with the "5 tons" of my gulf war days and the "10 ton" HMMTs. Take this into the battlemech universe and it is the maximum total of all things the mech must carry including its own engine, armor, armaments and fetures, but not including the cockpit, hardpoints and basic structure on which everything is mounted. Just my take I know, but it made sense to me...

If memory serves, cockpit systems and actuators are still counted in the 'weight limit', but I otherwise think this would be an accurate assessment. The '100 tonnes' is likely how much stuff beyond the base superstructure and sacrificial outer skin that you can cram into thing.

A fully loaded Atlas more than likely weighs more than a mere 100 tonnes.

[grimzod]

13 meters tall, 36 feet or so, not 100 feet tall. Atlas' are 13 meters tall.

[verybad]

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.

If it's heavy enough to crumple under it's own weight, then it's not habitable.There aren't many high G (over 1.5 G) planets inhabited at all, and ectremely few over 2G, at about 3G, the planet's atmosphere would probably start taking on many aspects of a Gas Planet like Nepture, Uranus, Saturn, or Jupiter.Once a planet holds Hydrogen in well, it starts getting real big...

I would reccomend keeping reality out of battletech, there are so many broken things that come from the rules that it'll chew you up and spit you out . If you ever get into the space side of things, the armor on warships is so light that in reality it would be thinner than a coat of paint for something the size they are.

Mechs don't make sense in the first place, tanks are a better, more compact machine.

[Colaessus]

If it was not 100 ton then it would say so.