Well, of course, I know that the question in the title is a bit too brand for the site, but will simplify it down the text so I hope it is more specific to answer. And yes, I know that histories don't need to be an "1:1 ratio" of realism, and need only to sound convincing, but I like to check reality first.
The simplified question:
So, for this question I will put the supposed informations of this contraption:
- The Mecha would be more or less the size of a human, like a fat power armor.
- The materials that would be used to build this thing (structure, cylinders etc) could be aluminium, steel or even carbon fiber.
- You can imagine that the entire system is a series of steps in the ground in sequence (like the lever, cylinders etc. So that it is easier to stipulate.
- First, a class-1 lever where the load would be a hydraulic/hydrostatic cylinder, and the force would be the hand/legs of a person.
- Second, I don't know much about these subjects myself, so I hope I don't make incorrect assumptions: Option 1 would to make a larger and shorter piston at the end of the lever that would impulsionate a longer but thinner cylinder, the option 2 would be the reverse.
- At the end of this thinner cylinder would be the final load, which, if wasn't a simple system laying on the ground, would be the weight of the mecha, the human and the cargo. Which I would put at worst at 300 kg in total.
How bigger this system and/or the parts of the system would required to be in order to lift something from 200-300 kg in weight with only the human force of a arm/leg?
The basic principles to this question:
In basic hydraulics, it is said that a small weight can lift a heavier weight by increasing the surface where the force is applied (and sacrificing distance in which work is done) as shown in the picture bellow:
Of course, this also resembles a little of the physical principles of lever mechanics, in which you distributes the force of a load all over a lever cable, sacrificing the distance the object is risen, as shown in the picture bellow:
Well, I don't know much about hydrostatics myself, but what I know is that hydrostatic transmission can be used both for vehicles (like a forklift) and for human-powered "animatronics", as used by Disney in this paper:
The idea:
Hyphothetically, if you had a 40km+ long indestructible lever on a indestructible fulcrum, you could lift the Eifel Tower with only your body weight.
With this in mind, the idea is to use these same principles (hydraulics/hydrostatics and levers) in order to increase the distribution of force without needing a 40km lever so a human pilot can power the legs and/or the arms to carry the system itself, themselves and up to 100 kg of cargo.
Yes, I would be "increasing" the "length" where the load is, but I would also increase the "length" where the force is being applied, increasing the distance in which the first move. If made any sense.
So, the simplified system would be like this:
- First, a class-1 lever where the load would be a hydraulic/hydrostatic cylinder, and the force would be the hand/legs of a person.
- Second, I don't know much about these subjects myself: Option 1 would to make a larger and shorter piston at the end of the lever that would impulsionate a longer but thinner cylinder.
- At the end of this thinner cylinder would be the final load, which, if wasn't a simple system laying on the ground, would be the weight of the mecha, the human and the cargo. Which I would put at worst at 300 kg in total.
Of course, the idea would be to add more levers and cylinders to move the upper part of limbs, like the thighs and the forearms. The hands and feet would be too complex and/or delicate to actually scale up.