I’ve heard building mechas is really difficult but there is no problem in building small humanoid robots (Boston Dynamics). So can’t we just upscale them and make mechas this way?
In: Engineering
Human shape is good for conserving energy while walking and for throwing things. If you’re running on actual engines instead of hoping not to starve over your next five days of death-marching that herd, and have projectile or launcher weapons that don’t need a baseball player to get their projectiles anywhere, it’s just lost most of its value.
When you go beyond the actual size of a human (armor’s one thing since we’re human-shaped, so load-bearing around you is something we’re working on that can do a lot for our soldiers) a lot of disadvantages prop up, from much of your mass being concentrated in each leg when you walk (tanks tear up the road, a biped the same mass would risks slamming its foot in the sewer) to being tall (higher center of mass, easier to spot). Lots of joints to armor too unless you want something that gets mobility-killed faster than a missile to the treads. You could get the advantages of height with a little sensor-boom or ‘periscope’, something we already do.
Many of the advantages would better serve a different shape: If you do need ‘limbs’ whether for swinging yourself around in microgravity without thrusters or for extending the reach of a weapon, that would still be better served – way better served – by taking advantage of not having to have it look human.
The biggest issue is power, all the other issues can be engineered away but without power non of it is going to work.
There are *lots* of problems creating small humanoid robots. Boston Dynamics is just starting to create usable ones now, and the most usable is a dog shape, not humanoid. See this “fails” compilation for why we might want to hold off on making them any bigger – [https://www.youtube.com/watch?v=g0TaYhjpOfo](https://www.youtube.com/watch?v=g0TaYhjpOfo)
Mechs for combat is an horrible idea. The reason tanks are so good is becuase they are compact (for a machine that is basically a moveing piece of metel), low profile and distributed that weight evenly across the surface.
If u hit the front then a tank is prob good but u hit the middle of a mech and u might seriously injure yourself from the fall if not die.
all that weight on two legs makes the weight on them alot and need to be seriously engineered. Think about how snow shoes work and u have a good idea why that is not a good idea vs tracks that can distribute weight more evenly.
They dont climb any better because anywhere a mech can go a tank can as well. U are not going to get a mech thru a forest any easier then a tank. Even worst for a swamp with all the weight on the legs.
Weapons on tanks are pretty good as they are and every shell u put on mech is added to the over burdened legs.
Hit the legs and the mech is toast while hit a tank tread and well also toast but u wont fall from 4-5 meters high off the ground. U just jump out and keep shooting
Mech are like very big humans. Big humans are easier to hit them small humans. 10x that and mechs are an rpg wet dream.
Mech Could be used in logistics but I dont see mech being combat rdy anytime in the near or distant future
Mechas don’t make any sense. Let’s break down why.
Let’s imagine you want a fighting Mech. A fighting Mech has a few problems.
1) It has a lot of moving parts. Parts that break, need oil, and get dirt and sand in the joints. Ideally, you would have as few moving parts as possible.
2) It’s a big target. Ideally, it would be low to the ground to make it harder to hit.
3) Legs get stuck too easily, and are too fragile. At low weights, something can walk on water without breaking surface tension, but at very high weights, something like mud would be catastrophic. Also, slips and falls would be devastating. What would be better, is to put that mecc on tracks, so you can disperse the weight more evenly, preventing it from getting stuck.
4) Too much armor. Armor adds weight, and mechas need armor everywhere. What would make more sense, is to have a lot of armor on the front, and little armor on the sides and back just in case, and to just face towards your enemy Mecha. That allows your Mecha to be both fast, and tough, in most encounters
5) Too many weapons. Mechas always have, like 12 machine guns, 8 missile launchers, a big weapon, and maybe a small weapon as well. But it would be more effective to just have a single, powerful gun, and maybe a single smaller gun for light support. That way, it’s easier to penetrate through heavy armor.
The thing is though, we already have something like this. The modern tank. And that’s kind of the point. Mechas look cool, but the design of a tank is for utility, not appearances.
Now, you might say that mechas have other uses too, but I will bet that for any use that a Mecha might have, you could use a cheaper, simpler, and more specialized thing to do an even better job.
Mecha just aren’t very practical
Sounds really cool, but in reality huge mechs would be easy targets, difficult to field maintain, etc. I think the future of robotic warfare lies in smaller more nimble machines. Wheeled/tracked, flying, maybe some walkers.
TL;DR: this is a material problem. A given material can only take so much force and as you scale things up, the forces climb until they just destroy any material you try to use.
This is a great question and applies to a lot more than just mechas (although mechas are certainly one of the coolest applications). The problem of scale can be seen in things like single cell organisms, more complex life, and even buildings and architecture. The scale of all of these things isn’t an accident.
Someone with a similar thought to yours might ask “Why haven’t some animals become enormous? Why can’t living things grow to the size of planets?” The reason is because of some very fundamental properties of physics. When you encounter something you perceive as solid, what you feel is that the molecules in that object are packed very closely and therefore attract each other strongly with different types of forces. These forces have a specific strength based on the shape and size of the molecules or atoms composing the solid.
If you scale this idea up, the hardness of an object depends entirely on how strongly the molecules inside it hold together. Now, let’s take steel. The molecules in steel pull together at a specific strength. From a mechanical perspective, there are two primary ways to apply force to this steel. These are compression (pressing down) and tension (pulling on both ends). For both types of force, there is a maximum tolerance based on the material you use. This tolerance would be higher for steel than paper because the molecules hold themselves together more strongly in steel.
With this knowledge, we can consider a giant, awesome robot. Well, what do we make this robot out of? Metal, probably. A paper robot would fall apart pretty quickly. What kind of metal? Well, probably a strong but light one? In that case, a good candidate would be titanium then. Now, let’s try making a gigantic robot. Well, what we find is that the bottom of the robot is being compressed by everything above it and any hanging parts are tensioning the parts from which they’re hanging. No matter how thick you make certain parts, others will be bearing its load. Now, it would probably be possible to create a robot 20 feet tall, but certainly not 100 or more. The design considerations for moving components under that much load simply defeat the capabilities of modern materials.
Mechas are generally a bad idea, especially combat ‘Mecha. Take for example an Atlas battlemech from the BT universe. Ingame fluff and all that gives it a height of some 50 feet or so. Figure probably 15-20 feet wide at the torso. That is a huge frontal target area in comparison to an 8 foot tall and 12 foot wide Abrams, standing in for a Patton/Rommel, looking at it from the front. You are more likely to hit the Atlas and from a lot further away than an MBT such as the Von Luckner, Patton, Rommel or Manticore.
I believe the biggest hurdle right now to make anything like that is the power supply. If we stumbled upon a arc reactor like Iron Man that was super powerful, light weight and cheap enough to produce to make it worthwhile, I imagine we could do some amazing things
It is a mistake to think we have “no problem” building those kinds of robots. Boston Dynamics makes cool stuff, but they have been at it a while and there is a reason we are don’t see their robots running around everywhere. They have a very limited battery life, and right now, they are so expensive you are better off with a traditional robot or even just hiring a guy to follow you around and do stuff.
Even if we had the technology for mecha (we don’t) they question would be, the question would be, what is a more effective military option, one mecha or six fighter jets and twenty tanks?
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