How to Make Mecha Work in a realish setting

[SVlad]

Seriously though... how about we settle this argument when mechs are actually a thing? This is getting stupid. I think everyone can agree that mechs require at least a little suspension of disbelief. Can you make "realistic" fiction with them? Sure. Are they going to be created in real life? Probably not, and even if they are, they're almost assuredly going to be remotely operated.

Just a ten years ago, when I heard about Elon Musk and his idea of reusable rocket, I thought exactly same thing in exactly same words about reusable vertical tail landing rockets. Literally it was something from cartoons and soft sci-fi.

Now I can't be so sure about mechas.

[MBehave]

You can't make something unless you dream it first, Human technology would not have advanced without imagination.

Seriously though... how about we settle this argument when mechs are actually a thing? This is getting stupid. I think everyone can agree that mechs require at least a little suspension of disbelief. Can you make "realistic" fiction with them? Sure. Are they going to be created in real life? Probably not, and even if they are, they're almost assuredly going to be remotely operated.

Just a ten years ago, when I heard about Elon Musk and his idea of reusable rocket, I thought exactly same thing in exactly same words about reusable vertical tail landing rockets. Literally it was something from cartoons and soft sci-fi.

Now I can't be so sure about mechas.

[Moik]

I went on the Boston Dynamics site to try and find out why they're making a bipedal/humanoid robot. Part of the reason seems to be just "pure" research (like how finding out that butterflies taste with their feet is a form of "pure" research). But, when describing their goals and what Atlas (the robot type) does compared to the other robots they make, the words "agility" and "mobility" come up a lot. Possibly a humanoid form would be better at certain "maneuvers" than tank-like ones. I don't mean individual level stuff like dodge rolls, but like unit level tactical stuff like aussie peels, or strategic level stuff like rapid tempo maneuvers. Maybe the "realish" validation for the mecha is that it's being used in asymmetric supply route disruption, like a large commando, and doesn't really get engaged by tanks or aircraft so those weaknesses don't come into play often enough to cause central planning to veto their development and use.

[bunnyboy]

The biggest advantage on mobility that human sized robot gain from walking, is that world (stairs, doors, cars, seats, etc) are built for humans.

[Jagged]

The biggest advantage on mobility that human sized robot gain from walking, is that world (stairs, doors, cars, seats, etc) are built for humans.

True. Humans are also built for the world. So it does make sense to copy nature, which we are doing more and more as our science/engineering improves.

[gaerzi]

The biggest advantage on mobility that human sized robot gain from walking, is that world (stairs, doors, cars, seats, etc) are built for humans.

Of course, this advantage requires the mech to be human-sized. So we're talking Terminator Combat Chassis rather than giant anime battlemech who's taller than the Burj Khalifa and flies around because it can and fights with a sword because it totally makes sense in-universe.

True. Humans are also built for the world. So it does make sense to copy nature, which we are doing more and more as our science/engineering improves.

There are things nature can't do. This in particular applies to issues of scale. For example, a human the size of an ant would pretty much die of hypothermia extremely quickly. An ant the size of a human would be crushed under its own weight and also asphyxiate. A bird the size of a whale isn't going to fly, or even walk. Whales swim and that's what any whale-sized animal would have to do.

It makes sense to copy nature when the solution nature came up with are applicable. Solutions that make sense at one scale, in one medium, for one speed; do not necessarily still apply when you change one of these factors. Sometimes they can apply if you change several factors, though, like imitating shark skin (slow speed in water) texture for aircraft paint (high speed in air), why not. But that's not a guarantee of success.

A giant human-shaped robot that walks around makes about as much sense as a giant flea-shaped robot that jumps around.

[Werra]

Of course, this advantage requires the mech to be human-sized. So we're talking Terminator Combat Chassis rather than giant anime battlemech who's taller than the Burj Khalifa and flies around because it can and fights with a sword because it totally makes sense in-universe.

Of course, convincingly realistic mecha is the premise of the thread.

There are things nature can't do.

Mecha aren't natural and so can be constructed from different materials that can overcome some of the limitations found in nature.

[Mithramuse]

Seriously though... how about we settle this argument when mechs are actually a thing? This is getting stupid. I think everyone can agree that mechs require at least a little suspension of disbelief. Can you make "realistic" fiction with them? Sure. Are they going to be created in real life? Probably not, and even if they are, they're almost assuredly going to be remotely operated.

Just a ten years ago, when I heard about Elon Musk and his idea of reusable rocket, I thought exactly same thing in exactly same words about reusable vertical tail landing rockets. Literally it was something from cartoons and soft sci-fi.

Now I can't be so sure about mechas.

While I think mecha are neat (Patlabor moreso than the oddball transforming ones etc.), I definitely fall more on the side of 'not gonna happen' though I also grant that you never know.

But vertical landing rockets? The US did that on the moon in the 1960s! Okay, yes, less gravity, but then McDonnell Douglas did the Delta Clipper prototype in the early 1990s... so it's definitely been out there for a while. The primary nemesis of the idea is politics and entrenched interests, which is why it took companies backed independently from NASA or the large defense companies to really get the idea to take off.

--Mithramuse

[SVlad]

But vertical landing rockets? The US did that on the moon in the 1960s! Okay, yes, less gravity, but then McDonnell Douglas did the Delta Clipper prototype in the early 1990s... so it's definitely been out there for a while. The primary nemesis of the idea is politics and entrenched interests, which is why it took companies backed independently from NASA or the large defense companies to really get the idea to take off.

Gravity and lack of atmosphere for MunMoon, yes. Delta Clipper never got behind prototype scale model, and I thought Mask would stuck on this stage too with Grasshopper. And as it happened with Virgin Galactic. Or Rotary Rocket. Or Lockheed Martin X-33. Or Skylon.

[MBehave]

VTOL aircraft, Harrier Jump Jet is from the 60s.
Earth Gravity and Atmosphere and proven track record of functionality.

But vertical landing rockets? The US did that on the moon in the 1960s! Okay, yes, less gravity, but then McDonnell Douglas did the Delta Clipper prototype in the early 1990s... so it's definitely been out there for a while. The primary nemesis of the idea is politics and entrenched interests, which is why it took companies backed independently from NASA or the large defense companies to really get the idea to take off.

Gravity and lack of atmosphere for MunMoon, yes. Delta Clipper never got behind prototype scale model, and I thought Mask would stuck on this stage too with Grasshopper. And as it happened with Virgin Galactic. Or Rotary Rocket. Or Lockheed Martin X-33. Or Skylon.

[Jagged]

A giant human-shaped robot that walks around makes about as much sense as a giant flea-shaped robot that jumps around.

Well obviously we disagree. I think we will see things like Aliens Loader in the near future and there are companies beating serious investiment money on this.

[discord]

all'yall: first off you are arguing two different things, MBehave is either talking bipedal robot, drone or power armor, not 'giant mecha', the bipedal form does not scale well.

MBehave: defining as either drone/robot/power armor is relevant, since they create different design constraints, but the one I am reacting to is armor thickness, cause that kind of thickness in the joints gonna be absolutely impossible while retaining flexibility, for armor 10mm might be possible on a drone/robot, for human operated use about 1mm works as proven by medieval plate armor design, you also forgot about the overlap needed for joints, or greatly lowered defensive capacity by using soft armor in the joints.

Do note, power armor is quite doable, even at our current technology level, the best efforts of 'giant mecha' are... laughable and sad.
Protection levels would be quite lower though, to keep weight and volume down, and would probably be better rated on the STANAG 2920 scale rather than 4569(body armour rather than vehicle armour).

But yes, power armour pretty much immune to current small arms is doable, and currently being worked on by many parties, the problems however are in the 'drive train' so to speak, not the armour.

Weapons would probably be infantry crew served weapons, not vehicle weapons, volume and weight are both issues.

Bottom line, power armour is an engineering problem, mecha is a science problem.

[MBehave]

Joints are always going to be a weak point, the limbs would have plates that overhang just like medieval armour and you can make them as thick as you want.
They have gaps and in plate armour they had chainmail under it.
If you are talking about this chainmail under the plate joints to deal with the gaps you are correct, as long as it defends agasint small arms fire i don't see it being a problem.
Tanks have the same problem with their tracks and drive system, tanks are often disabled due to loss of mobility when say a RPG hits them.

It may sound funny but not all battletech mechs are stupid.
I thought big mechs were unrealistic but decided to compare actual sizes.
I did a to scale comparison of a m1a2 tank in the following image.
Remove the 2 missile launchers from the MadCat and its actually capable of having comparable armour to a tank at its mass.
Direwolf is also a mech that for its given mass could actually be realistic.

Madcats feets surface area on a single foot is greater then the tanks both tracks.
I think as a general rule battletech mechs need +20tons added across the board to their mass to have a hope of being realistic.



There is one situation where large mechs would beat tanks.
If heat becomes an issue like thin atmosphere/no atmosphere/weapons. a Mech is going to radiate heat faster then a tank can due to more surface area to volume.

all'yall: first off you are arguing two different things, MBehave is either talking bipedal robot, drone or power armor, not 'giant mecha', the bipedal form does not scale well.

MBehave: defining as either drone/robot/power armor is relevant, since they create different design constraints, but the one I am reacting to is armor thickness, cause that kind of thickness in the joints gonna be absolutely impossible while retaining flexibility, for armor 10mm might be possible on a drone/robot, for human operated use about 1mm works as proven by medieval plate armor design, you also forgot about the overlap needed for joints, or greatly lowered defensive capacity by using soft armor in the joints.

Do note, power armor is quite doable, even at our current technology level, the best efforts of 'giant mecha' are... laughable and sad.
Protection levels would be quite lower though, to keep weight and volume down, and would probably be better rated on the STANAG 2920 scale rather than 4569(body armour rather than vehicle armour).

But yes, power armour pretty much immune to current small arms is doable, and currently being worked on by many parties, the problems however are in the 'drive train' so to speak, not the armour.

Weapons would probably be infantry crew served weapons, not vehicle weapons, volume and weight are both issues.

Bottom line, power armour is an engineering problem, mecha is a science problem.

[discord]

MBehave: I do not want to be that guy, but no, it simply will not work, not with current science, probably not ever.

First off, feet size vs tracks, the ground pressure on tanks tracks is actually lower than humans, this really does not matter that much since the area absorbing the TOTAL weight can't handle it.
The classic example is a bridge, you can march a million humans over the bridge, but not a single 60ton tank, despite the tank having 'lower ground pressure'.

Second Those feet are gonna have to be articulated and handle those kinds of weights, for a mecha to work it needs to have that on a single foot, or rather a portion of a single foot, as anyone working on groundpressure in human running will tell you, it's not even close to being equal pressure spread out under the foot...

Third ground pressure on a bipedal system goes up as you increase speed, mech running will have shear pressures high enough to rip steel to pieces, we do not have materials capable of handling those kinds of forces.

Fourth, Armour, specifically 3 dimensional surface area will be much greater as compared to ordinary tanks, this leads to higher percentage of weight/protection levels, there is no way around this one by the way, short of forcefields?

fifth: We do not have a viable propulsion system for practical mechs.

So yeah mecha are cool but we do not have the science to make them even impractical, at this time they are a bad joke.
kindly watch the following
https://www.youtube.com/watch?v=Z-ouLX8Q9UM

Bottom line: Power armour are an engineering problem, mecha a science problem, and nothing short of handvawium will give a mech anything another shape can't do better.

[gaerzi]

Mecha aren't natural and so can be constructed from different materials that can overcome some of the limitations found in nature.

And that's where "imitating nature" stops being useful. Our airplanes aren't ornithopters, putting a couple of turbojets under the wings is a much better solution than flapping said wings. Likewise, race cars propel themselves by rotating wheels, not by moving legs.

Well obviously we disagree. I think we will see things like Aliens Loader in the near future and there are companies beating serious investiment money on this.

The Alien power loader is an over-engineered forklift. It can make sense for rough, accidented terrain where wheels or tracks would not be practical. But even then, such a thing IRL would probably end up looking less like a human-shaped vehicle and more like some sort of freakish centaur thing, because to distribute weight better you'll need more legs. (And if you don't have a problem with distributing weight, that means the things you're trying to carry are not heavy enough to deserve a machine, so a human-shaped actual human would be sufficient, no need for a human-shaped robot.)



You'll notice that thing above is not a military combat vehicle. Sure, you could imagine jury-rigging one into a makeshift artillery platform or something -- but at the same time, it's probably easier to just bolt an anti-air gun to a Toyota technical. Like a Texan plumber was dismayed to discover:



When you're talking about making realistic mechas work by imagining them as utility vehicles that are then makeshift transformed into war weapons, you'll still have to compete with things that are just more efficient at being vehicles. Basically, you'd be seeing Mad Max war trucks in a realistic setting before you'd be seeing mechas in a realistic setting. Because we're basically already seeing them IRL.

There is one situation where large mechs would beat tanks.
If heat becomes an issue like thin atmosphere/no atmosphere/weapons. a Mech is going to radiate heat faster then a tank can due to more surface area to volume.

Interesting thought, but there are other ways to mitigate heat. Such as pumping it into the munitions before firing them. Some aircraft already use a variant of this idea, by using their own fuel as liquid coolant system -- you put the heat in a material that is then expelled from the aircraft (as long as the engine works, at least; but if it doesn't you'll have more immediate problems than heat dissipation not being optimal anymore).

[MBehave]

Humans have lower ground pressure not higher then tanks.
Even listed on Wiki
https://en.wikipedia.org/wiki/Ground_pressure

Do you have some math to explain shearing would be a problem?
Cranes capable of lifting massive amounts exist and they are made from steel.
The majority of their weight is counter balance NOT actual structural.
Big Carl can handle 3000 tons extended over 250m.
Shearing force exerted at the Fulcrum(main body) from the load alone is far past anything a 30m high 100 ton mech would EVER see in compression/tension/shearing if jumping as far as I can work out.

Materials for a 100ton mech would need to handle if we are using humans as an example about 10 times its total weight on each foot if running(both feet leave the ground during stride). For walking(both feet do not leave the ground) it needs about 2-2.5x
These are compression and tension forces, which even mild steel can handle completely fine.

You will find higher compression/tension/shearing forces on the wing of a super sonic fighter pulling g's.

Battletech mechs are giant targets, I wasn't saying they were a good idea, I was saying add in at least 20 tons to the average weight and they are "doable" for their given mass and in a situation where you need to bleed off heat for weapon systems mechs would be superior to tanks.

MBehave: I do not want to be that guy, but no, it simply will not work, not with current science, probably not ever.

First off, feet size vs tracks, the ground pressure on tanks tracks is actually lower than humans, this really does not matter that much since the area absorbing the TOTAL weight can't handle it.
The classic example is a bridge, you can march a million humans over the bridge, but not a single 60ton tank, despite the tank having 'lower ground pressure'.

Second Those feet are gonna have to be articulated and handle those kinds of weights, for a mecha to work it needs to have that on a single foot, or rather a portion of a single foot, as anyone working on groundpressure in human running will tell you, it's not even close to being equal pressure spread out under the foot...

Third ground pressure on a bipedal system goes up as you increase speed, mech running will have shear pressures high enough to rip steel to pieces, we do not have materials capable of handling those kinds of forces.

Fourth, Armour, specifically 3 dimensional surface area will be much greater as compared to ordinary tanks, this leads to higher percentage of weight/protection levels, there is no way around this one by the way, short of forcefields?

fifth: We do not have a viable propulsion system for practical mechs.

So yeah mecha are cool but we do not have the science to make them even impractical, at this time they are a bad joke.
kindly watch the following
https://www.youtube.com/watch?v=Z-ouLX8Q9UM

Bottom line: Power armour are an engineering problem, mecha a science problem, and nothing short of handvawium will give a mech anything another shape can't do better.

[Overkill Engine]

Humans have lower ground pressure not higher then tanks.
Even listed on Wiki
https://en.wikipedia.org/wiki/Ground_pressure

From that exact same wiki page:

Note: The pressures for adult human male and horse are for standing still position. A walking human will exert more than double his standing pressure. A galloping horse will exert up to 3.5 MPa (500 psi). The ground pressure for a pneumatic tire is roughly equal to its inflation pressure.

[MBehave]

Were talking tracks not tires, which doesnt really matter.
I was pointing out some battletech mechs(the madcat) on a single foots surface area is greater then a tanks, Madcat would have less ground pressure then a tank even on one foot.

PS the M1 used for the wiki is the original mass 54t
from Theory of Ground Vehicles 2001 edition.
m1a2c is 68t so humans beat it even on one foot walking


Thats not even half the story through.

A human can walk across muddy ground that a light tank cannot travel over.
why?
Because the downward pressure is the majority of all pressure exerted by the bipedal movement, while the rotational diagonal force of a wheel/track exceedes the downward pressure.

Humans have lower ground pressure not higher then tanks.
Even listed on Wiki
https://en.wikipedia.org/wiki/Ground_pressure

From that exact same wiki page:

Note: The pressures for adult human male and horse are for standing still position. A walking human will exert more than double his standing pressure. A galloping horse will exert up to 3.5 MPa (500 psi). The ground pressure for a pneumatic tire is roughly equal to its inflation pressure.

[discord]

MBehave: Actually yes it does matter, what overkill engine pointed out was the difference between human standing still and human walking(which doubles the pressure) and the example with horse told the simple tale of 20x higher... so yes, a running(or jogging, or even a slightly larger than average just walking) human has a higher ground pressure than the big McFattie M1 Abrams.

And no, the reason humans can walk over those muddy terrains is because humans can choose the best area to walk over that are much better compared to the 'average' whereas the tank can not....oh and that annoying total weight over area comes into play again on 'soft' ground.

And no again, the shear forces come from SPEED and impact.
Lets take the classic Timberwolf(Mad Cat for you inner sphere freeborn scum) as the example.
It has a top speed of 86.4km/h, a gait length of what? lets be wildly optimistic and say 24m which gets us a nice even number of one full step per second, those legs need to swing back and forth really fast....
so, that foot you calculated has a surface area larger than abrams(you probably skipped the fact that it is not a flat even round or square surface, it is a three toed foot.) that needs to absorb the impact of a 75 ton mech moving at 24m/second, true not ALL of that will be going down, but a lot of it will, and when you add in that it will take that force on a single rear toe..... it is just not possible...
Just crunched some numbers on it, that would either rip apart super reinforced airfield runways when you effectively slam well over 2kg(more likely closer to 5kg but rounding down a lot to give it every chance possible) of shaped charge TNT equivalent of energy into it on a surface area of 1/4 meter(probably less, but giving it every chance possible.) or the foot, one of them will break, probably both.
And I will not even get into traction, ye gods that would be a mess.
So yeah, that gait thing does not scale well at all.

But this thread is about coming up with some plausible explanation why mecha actually could be a thing, so stop talking about science stuff, if science could give us a reason why mecha could be a thing we would already have them, and no need to ask for IMAGINARY reasons why we could have them.

[bunnyboy]

Nobody had not yet talked about what happens when the vejivle takes small damage.
Tank: one of tracks break. It can still drive (badly) in circle and shoot around while the crew is still unharmed.
Mecha: one of the legs break. It falls down, it weapons are under it and the crew is hurt from bouncing in their seats down half of the mech height.