9 replies to this topic

[Zoolad]

Good evening folks! Just a question that has been bugging me for a while (years) about Battlemechs in the Battletech universe... do the tonnages actually reflect the raw mass of the mechs? Or are they masses of some component? The reason I ask is, mechs are HUGE (I'm sure you all realize), yet they seem rather light based on their weight classes. Something like say... a Catapult is at least 15-20 metres high and ~10 metres across based on the cockpit size, yet it only weighs 65 tons. Comparing that with say.. a modern M1 Abrams tank (~2.44m in height and ~9.77m in length according to Wikipedia), which weighs ~60 tons, the Catapult seems really really light. Is there a reason for this? Are the mechs just made of some super light material?

[Fabe]

This might answer your questions
http://www.sarna.net...Mech_Technology

[dal10]

the tallest mech in existence is the atlas at 14 meters.

the wasp is 9 meters.

[Nebfer]

Their tonnage is their in universe loaded combat weight, so if a 100 ton battlemech loaded with ammo and what naught, where to step onto a scale it would weigh 100 tons (at lest on a world that is 1G). Now you can pick up objects and have it weigh as much as 120 tons (if it has TSM), though if you have a mech with specific cargo handling gear you can allow a mech to carry twice it's loaded weight, or Said 100 ton mech could carry a max of 200 tons externally (though you typically do not see that sort of gear on battlemechs).

So to find the empty weight of a battlemech one needs to subtract the mass of ammo, mass of life support (food, water, and the like though no figures have been stated I believe), coolant for the heat sinks (non directly stated though the coolant pod requires .1 ton of coolant per unit, heat sinks probably are not much different ratio wise to their coolant & radiators), the weight of the pilot and a few other items I would not know of, and lastly if it's an "Omni" any non fixed items.

So perhaps on say a Atlas 7D
5 tons of ammo
.5 to 1 ton of various items (including pilot)
2 tons of coolant (assuming .1 tons per heat sink)
So 7.5 to 8ish tons or an empty Atlas 7D could be around 92.5 to 92 tons in weight (at the very lest it's 95 tons due to no ammo on board).

On the other hand a Clan Dire Wolf (a 100 ton Omnimech)
.5 to 1 ton of various items (including pilot)
1.5 tons of coolant (assuming .1 tons per heat sink)
50.5 tons of pod gear
So an Empty Dire Wolf would weigh 47 to 47.5 tons with the above assumptions (or just 49.5 tons with out).

[Zoolad]

That still suggests Battlemechs are outrageously light for their size. Just knowing the rough mass of machinery in real life, an Atlas should be at LEAST 1000 tons.. if not more. I was assuming maybe the tonnage refers to the amount of "stuff" (ie. weaponry, ammo, fuel, engine, gyro, etc.) the chassis is capable of carrying, IN ADDITION to it's existing mass? Like maybe an Atlas is ~1000 tons and is capable of carrying 100 tons of cargo on its frame?

[Fabe]

Zoolad, on 16 November 2013 - 10:18 PM, said:

That still suggests Battlemechs are outrageously light for their size. Just knowing the rough mass of machinery in real life, an Atlas should be at LEAST 1000 tons.. if not more. I was assuming maybe the tonnage refers to the amount of "stuff" (ie. weaponry, ammo, fuel, engine, gyro, etc.) the chassis is capable of carrying, IN ADDITION to it's existing mass? Like maybe an Atlas is ~1000 tons and is capable of carrying 100 tons of cargo on its frame?

Or Battlemech are made from very light but strong materials.

Quote

Internal Composition

BattleMechs have a large amount of articulation (joints). The basic design approach is to mimic the skeletal structure of humans by using an endo-skeleton. This means that most BattleMech systems are mounted to the exterior of the internals ("bones") instead of being caged in a frame. This is somewhat similar to how a human skeleton supports muscles, organs, and the rest of the human body. It is the internal structure ("bones") that support the whole structure. A 'Mech's armor only looks like it could hold it together... 'Mech armor is actually quite thin and unable to support much weight.
The Internals

'Mechs normally have around sixteen to twenty five bones. The low number of bones compared to human structure is due to couple of reasons: some structures that encompass a dozen or more bones in a human - for example the ribcage - are a one piece structure in 'Mechs. In other areas, simplified components serve the function of several bones. The human foot is a very complex structure of bones, yet it is replaced effectively with simple shock pads. This structural streamlining results in 'Mechs generally being less articulated and flexible than a purely human bone structure would allow.
The exterior of the bones are configured to mount the assorted equipment 'Mechs carry. Struts extend outward from the bones to hold the armor shell. Attachment points for the myomer "muscles" and various electrical servo motors are built onto the bones. All of the internal structure (bones) are rigged for easy attachment of sensors and equipment.
Weapons frame attachments, however, are custom designed into the internals for each 'Mech. Sometimes a bone is built around a weapon which attaches directly to that bone, such as the Panther's ppc. Sometimes weapons are attached on an independent mount which "sits between" the weapon and the bone and is attached to both, such as the Shadowhawk-K's shoulder PPC mount. In fact, different weapon models (even of the same class, like two different models of medium lasers) require different mountings. For these reasons there is always some customization, design, and engineering work required to mount different types or classes of weapons or even different models of the same weapon class in any particular BattleMech. OmniMechs are much easier to configure for mounting weapons because OmniMechs are designed to be modular.
Standard Internals

Standard Internals are formed of multi-part structures with a core of ultra-light foamed aluminum, shrouded in directionally oriented stressed sheets of silicon carbide mono-filament fibers. The fiber layer is also rigged with structural sensors and data lines. This core is then clad with titanium-alloyed steel.
Endo-Steel Internals

Endo-Steel internal structures are of the same basic configuration as Standard Internals. The major difference is in materials. Endo-Steel structures are made of endomorphic steel.
Endo-Steel is much stronger than standard internal structure allowing endo-steel internals to be built with structurally thinner walls and no fiber wrap reinforcement around their core (they still have the sensor and data lines wired into them, though). Endo-steel has the same strength as thicker walled standard internals which results in a lighter structure that is bulkier.
The downside is that the thinner walls make endo-steel internals less stiff than same diameter of Standard Internals, which means that endo-steel bones must be made with larger cores. It is necessary to understand that stiffness and strength are not the same qualities. For example a thick cardboard panel is stiffer... less likely to buckle, than a thin sheet of metal, even though the metal is far stronger. Endo-Steel is stronger, but its thinner structures are far more likely to buckle, requiring a physically larger core to support the same amount of weight that standard internal structure can.
Due to its composition, endo-steel must be made in zero-g to avoid chemical segregation (think of oil and water) which would severely weaken the alloy and make it brittle. Endo-Steel's foamed aluminum core is also formed in zero-g, which promotes a more regular pore size, giving the core superior strength. Zero g production makes endo-steel more expensive, but allows the elimination of the fiber layer, meaning faster production than standard internal structure.

[Arnold J Rimmer]

As I understand it, the mech itself is the structure, which includes musculature/motivators. So each mech is carrying ten or twenty times its own weight - the engine, armour, ammunition, coolant, heatsinks, weapons, pilot (and comestibles)...etc. up to its combat/maximum weight rating; 100 tons for the Atlas.

[Nebfer]

Zoolad, on 16 November 2013 - 10:18 PM, said:

That still suggests Battlemechs are outrageously light for their size. Just knowing the rough mass of machinery in real life, an Atlas should be at LEAST 1000 tons.. if not more. I was assuming maybe the tonnage refers to the amount of "stuff" (ie. weaponry, ammo, fuel, engine, gyro, etc.) the chassis is capable of carrying, IN ADDITION to it's existing mass? Like maybe an Atlas is ~1000 tons and is capable of carrying 100 tons of cargo on its frame?

Nope an Atlas is 100 tons and ~13 meters tall, but yes most battlemechs would technically float due to their volume, even more fun is the fact that dropships & warships are even lighter on a volume basis.

Though mass to volume issues are nothing new it's a fairly common scifi problem. For example in later UC era gundam the mobile suits are 18ish meters tall and only 20ish tons in their empty weight, and only gain like 10-30 tons more in fuel and weapons.

[dal10]

dropships do indeed float. see Mercenary's Star. the gray death steamshipped a dropship across an ocean while using its mostly flooded lower levels as balast.

[akakiwu490]

Nebfer, on 17 November 2013 - 06:08 PM, said:

Though mass to volume issues are nothing new it's a fairly common scifi problem. For example in later UC era gundam the mobile suits are 18ish meters tall and only 20ish tons in their empty weight, and only gain like 10-30 tons more in fuel and weapons.

I mean I feel like this gets a little suspension of disbelief. After all we're making a lot of conceits to get to battlemechs, like myomers, neurohelms, etc.

But of all the leaps that concern me least it seems like ultralight/ultrastrong materials is the least likely bump in the road. In the Bronze age the idea of steel swords that were lighter and stronger would have seemed preposterous. Not too long ago we'd have said we've already done all you can with metallurgy, and yet we're creating carbon nanotubes which are insanely strong and insanely light.

TL;DR of that is of all the things to over-think, I'd say the weight of a battlemech is one of the most feasible parts of the whole deal.