290 replies to this topic

[tenderloving]

You guys keep comparing these things to tanks in weight, which is just wrong. They are constructed more like aircraft. They are also being made in the 31st century. Think about the strength-to-weight ratio of metals today versus the metals used in the 19th century. Expand that for a couple thousand years.

[DauntlessK]

I find it hard to believe that with the similar, parallel advance in weaponry, that armor would get thinner. Yes it would be advanced to become thinner if weapons stayed the same. But they do not.

Why would you outfit a 100ton battlemech with a few CM thick worth of armor when you COULD thicken the armor to better withstand enemy fire that WILL eventually destroy you? Saving money??? I doubt it.

I have always wondered how these tall battlemechs could only weigh as much as they say they do and cannot believe that those are correct, actual weights.

[Death Mallet]

It's just made up science for the benefit of an easy way to design the game numbers. . . from back in the day when nobody cared about such things in their tabletop games.

Yes, it would weigh far more than 100 tons.

Edited by Death Mallet, 13 June 2012 - 04:38 PM.

[Vandul]

Vassago Legion, on 13 June 2012 - 02:45 PM, said:

I've always thought the 100 ton "limit" was absurd when the Germans had a tank, Maus, in WW2 that weighed 188 tons, and it only had one cannon. Tanks aren't solid either, Some of them have enough room for 5 or 6 people.

The Maus was actually designed to carry a 12.8cm main gun, and a 7.5cm auxillary gun. She was supposed to have a crew of six.

[Deathjester]

Kartr, on 13 June 2012 - 04:19 PM, said:

What is the volume of an Atlas?

Why would the heat sinks be mounted on the outside? Important equipment such as heat sinks would be mounted behind protective armour, not on top of it. If the 'mech isn't sealed than air would pass over the heat sinks via convection currents with ingress at the bottom of spaced armour plates and egress at the top.

Most vehicles aren't fully sealed either, off-road vehicles are designed with this in mind to allow them to ford rivers. 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.

Corrosion of critical components? That's what sacrificial anodes are for, any delicate equipment could be made to IP66 standard (or whatever they use at that point). As for electrical shorts, have a look at an airfield lighting and telemetry system or automation and robotics products installed in an industrial or food processing setting. Power is supplied to fully sealed components by series isolation transformers, cabling and devices are frequently submerged for long durations in water, mud, oil, even blood. These are complex and durable devices that continue to operate in far from optimal conditions.

Edited by Deathjester, 13 June 2012 - 04:48 PM.

[Kartr]

tenderloving, on 13 June 2012 - 04:31 PM, said:

You guys keep comparing these things to tanks in weight, which is just wrong. They are constructed more like aircraft.

How so? Why do you think they're being constructed more like aircraft than tanks? Also how does that have any bearing on whether they mass to little to be more dense than water?

tenderloving, on 13 June 2012 - 04:31 PM, said:

They are also being made in the 31st century. Think about the strength-to-weight ratio of metals today versus the metals used in the 19th century. Expand that for a couple thousand years.

Strength to weight is only important for creating the structural members, modern high velocity weapons makes weight to strength much less important that density when it comes to armor. In the future this is going to be even more true when you're using the epitome of high velocity weapons (gauss rifle) and you're shooting multiple high velocity rounds every "shot" (AC/s). Not to mention the whole "less dense than water" problem again, which exists no matter what technobabble future materials you conjure to explain the improbably light mass.

The problem isn't in the materials people, it doesn't matter how light you can make the structural components or the armor or anything else if it's still less dense than water. Lets not even get into the problem of volume that most 'Mechs suffer, which only compounds the density problem. (Basically there's not enough room in most 'Mechs for all the ammunition and feed systems, which means they need more than their pictured volume which makes them even less dense)

[Brasidias]

Never really thought about it. I just assumed the weight class had to do with how much weight they could carry.

[Robby Vitriolic]

I just suspend disbelief when playing. Not a perfect solution, but works for me.

Or, we could agree that in the future, a 'metric ton' weighs more than it does at present time. Interstellar standards and all. As in, there could be a canon source that says a metric ton in this universe is equal to a metric ton circa 1985, but they still got it wrong.

Add in all those decent arguments about material advancements and we are good to go.

[DauntlessK]

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

The problem isn't in the materials people, it doesn't matter how light you can make the structural components or the armor or anything else if it's still less dense than water. Lets not even get into the problem of volume that most 'Mechs suffer, which only compounds the density problem. (Basically there's not enough room in most 'Mechs for all the ammunition and feed systems, which means they need more than their pictured volume which makes them even less dense)

Exactly what I mean when I said that I find it hard to believe that with the similar, parallel advance in weaponry, that armor would get thinner. That suddenly you can afford to have a bunch of empty space just because it weighs less.

Tell me what you'd do as a designer if there was a new armor that was twice as thin and could stop your bullet easier. You'd simply design a better projectile, whether that means bigger, faster, harder, etc. And then what? Eventually you'd have a weapon that could outdo that armor, so you can either improve the armor technology again or thicken it to the orignal thickness, or both.

[Kartr]

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

What is the volume of an Atlas?

Using the stated max height of a BattleMech from sarna, which is 14m and doing a quick estimation the Atlas has a volume of roughly 378m^3. Which is roughly 265kg/m^3 which means it falls somewhere between cork and lithium and just over 1/4 the density of water.

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

Why would the heat sinks be mounted on the outside? Important equipment such as heat sinks would be mounted behind protective armour, not on top of it. If the 'mech isn't sealed than air would pass over the heat sinks via convection currents with ingress at the bottom of spaced armour plates and egress at the top.

That is a possibility although I would consider those heatsinks to be outside of the 'Mech proper. In addition even if the armor was spaced like that it wouldn't change density as the water flowed by as the water is not contained inside the 'Mech and can move freely away as the 'Mech starts to float.

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

Most vehicles aren't fully sealed either, off-road vehicles are designed with this in mind to allow them to ford rivers. 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.

Most vehicles are also much more dense than water and don't need to be filled with water in order to prevent floating. They still have joints which can get clogged. Besides BattleMechs handle more than just "a bit of water" when they're fully submerged and during their normal operations over their entire multi-century lifespan. Besides whether or not they can handle getting water in their small areas is besides the point of their extremely low density.

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

Corrosion of critical components? That's what sacrificial anodes are for, any delicate equipment could be made to IP66 standard (or whatever they use at that point). As for electrical shorts, have a look at an airfield lighting and telemetry system or automation and robotics products installed in an industrial or food processing setting. Power is supplied to fully sealed components by series isolation transformers, cabling and devices are frequently submerged for long durations in water, mud, oil, even blood. These are complex and durable devices that continue to operate in far from optimal conditions.

Yes but how many centuries are these things rated for and how does that make BattleMechs suddenly become 4+ times more dense than they are? Even if you assume that a BattleMech is nothing more than a thin shell and is completely filled with water when submerged, or partially submerged, its over all density is still going to be less than water which means it will still float.

[Makaveli]

My Atlas has been putting on a few pounds latley.... But Im scared to say anything to her about it.... I mean, AC20, HELLO!

[FrostPaw]

I think you're pondering a question that was never asked when the games original concept and rules system was thought up. Anotherwords.....you're overthinking science fiction and trying to make science fact fit into it.

[Deathjester]

Kartr, on 13 June 2012 - 05:09 PM, said:

My points were to backup my theory that a mech doesn't have to be fully sealed and therefore most of the internal volume would not contribute to its density. Most of the componebts of a battlemech wouldn't be the original ones that they started off with either, most mechs are a shadow of their former selves due to substandard maintenance and non-standard parts over the course of their service.

Must say, it's not every day that I get to debate future robot technology with a US marine.

For anyone who is interested, an interesting article that covers most of the topics covered in this thread.
http://www.sarna.net...Mech_Technology

[KBone]

SSSSHHHHHHHH......

you guys are shattering my reality....

[Kartr]

Deathjester, on 13 June 2012 - 05:24 PM, said:

My points were to backup my theory that a mech doesn't have to be fully sealed and therefore most of the internal volume would not contribute to its density.

Hmm when you put it that way... the volume would be less than the solid block we see since it would only be made up of component parts. That could work though without knowing the volume of all the parts that make up a 'Mech, or more easily the volume that isn't taken up by parts we have no way of knowing if this would work. Plus we don't know that they aren't sealed which would blow this hypothesis out of the water so to speak.

/shrug

Personally I think its a far simpler and more logically sound theory to say that BattleTech "tons" are not the same thing as real tonnes. There just have to be to many things that line up perfectly in order for them to be the same thing. 'Mechs can't be sealed, the total volume of all parts of the 'Mech has to be low enough to ensure that it's density is plausible, and it has to overcome being just over a quarter the density of water minimum. The total (portions of the 'Mech sealed to water) volume would have to be 85m^3 in order to equal the density of plastic (for any 100ton 'Mech).

Deathjester, on 13 June 2012 - 05:24 PM, said:

Must say, it's not every day that I get to debate future robot technology with a US marine.

Heh fun huh?

[Skylarr]

Quote

Kartr, on 13 June 2012 - 07:53 PM, said:
Actually he's not right, there is no possible way for a "BattleTech Ton" to be a metric ton. If this were the case then the Atlas would be less dense than water and be unable to submerge, possibly not even go more than waist deep in the water. Its a convenient scale to design and classify 'Mechs around not an actual measure of mass or weight.

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????

Kiriko, on 13 June 2012 - 04:00 PM, said:

Tech Manual 35103, pg18, Construction Basics, Weight (Mass):

"In Classic BattleTech, most units are measured by their weight, or mass. The Classic BattleTech universe uses the metric system, with all objects defined by their weight in kilograms or metric tons. In TechManual construction, units may be constructed under the kilogram standard (battlesuits, ProtoMechs, and Small Support Vehicles) or by the tonnage standard (BattleMechs, Industrial-Mechs, Combat Vehicles, Medium and Large Support Vehicles and aerospace units)."

Edited by Skylarr, 13 June 2012 - 05:59 PM.

[Solis Obscuri]

Kartr, on 13 June 2012 - 03:53 PM, said:

Actually he's not right, there is no possible way for a "BattleTech Ton" to be a metric ton. If this were the case then the Atlas would be less dense than water and be unable to submerge, possibly not even go more than waist deep in the water. Its a convenient scale to design and classify 'Mechs around not an actual measure of mass or weight.

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.

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.

[Skylarr]

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

(Basically there's not enough room in most 'Mechs for all the ammunition and feed systems, which means they need more than their pictured volume which makes them even less dense)

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

[Goldhawk]

Some engineer created a 100 ton Atlas. It was "exactly" 100 tons.

Hey Earl?
Yup?
This Atlas here weighs only 99.992 tons!
Did you add the pilot?
The pilot's that heavy
Yup.
Well, then, I guess we're done here.

My Atlas could afford to lose some weight, let me unload some of my ammo into your mech. That will lighten my load....

[Thomas Hogarth]

It's been speculated by people that write for Catalyst that are smarter than I am that 'Mechs have similar densities to foam. That's right, by all rationale, 'Mechs should float quite easily and be blown over in a light wind.

Some may assert that it's easier to simply add a zero to the end of the weights. I think this leaves us with non-sensical machine gun weights. Easier to just assume that it weighs more in some manner or another and move on.