Semi-Viable Mecha Idea?

[Sea Skimmer]

*COLOSSAL SIGH* I was addressing the point that mooks on foot could bring them down with heavy infantry weapons (namely missiles and rocket-propelled grenades). Obviously, it's not god mode, and obviously (to everyone but you tank crusaders, apparently) no one is disputing that tanks are overwhelmingly superior to mecha which I and everyone else ITT readily concede are utterly infeasible. You guys are preaching to the converted and frankly, it's just an itty bit irritating. How about instead of flogging that dead horse some more you try and participate in the spirit of the thread? You know, suspension of disbelief?

How about no, what you want a thread to be about it not what it has to be about. The thread is in Sci Fi, not Fantasy, and it asked if a certain mecha concept was viable, a question which has been answered. It did not ask to justify mecha by whatever means possible. I can think of things sure, they all involve some degree of deliberate stupidity, like mecha bodyguards as status symbols, or maybe a non combat role of assembling an bailey bridge with overscaled parts. Hey they could even be used to throw camo nets over precious tanks, saving the tank crews as much as ten minutes of labour.

But if you’re going to justify them by any means necessary, then why the fuck even bother? Name any reason you want and it’s just as meaningful as any other when you’re forcing the scenario to fit a conclusion. Whatever specific excuse you could up with going to be scenario dependent, generalizations are more irrelevant then ever.

In this genre, we've got mecha, so try and figure out why. Justify their already established existence. Starfighter threads rarely devolve into such tedious bash fests and they're a fundamentally broken idea too. It's pointless to keep harping on how much starfighters and mecha suck because people like them and thus will use them in their fiction.

What genre? What established existence? ‘tossing this idea around a while back’ is now a genre which MUST have mecha?

[Sea Skimmer]

If electronics and related technologies advance enough while materials tech can not improve more than a relatively limited degree (still constrained to real-world elements in the periodic table), the ratio of the effectiveness of heavy physical armor to that of active protection systems tilts more and more in favor of the latter.

And if you then scale down your armor in response to that, the enemy can scale down his cannons too, and then more easily overwhelm you with volume of fire, since artillery ammo is always going to be damn cheap and doesn’t need guided shells for decent accuracy firing APFSDS. Say you drop to 25 tons and only have armor against 40mm automatic cannon. The enemy then fields a 57mm gun firing 200rpm from a 90 round ready magazine.. this is not good unless you happen to have 90 ready rounds for your active protection system.

As it is tank guns can already shoot at as much as 8-10rpm, but no reason actually exists why automatic loading gear couldn’t be developed that would fire much more quickly. The Dutch had a 120mm naval gun in 1950 for example that fired at 45rpm. The prototype only OTO air defence tank mounted a 76mm gun firing at as much as 120rpm and it was only 1970s technology.

Gunfire can be coordinated between multiple vehicles to overwhelm individual enemy units as well, without requiring any increase in rates of fire. That’s already doctrine for many armies and was common place in WW2 when accuracy was lower, all tanks in a platoon shoot at one enemy until it burns, then shift to the next one. All the various intranet systems people are putting on tanks will go a long way towards facilitating this, Eventually fire direction might be entirely automated, with human commanders being required only to verify targets and approve them for destruction.

So in reality, its likely that active protection will be required just to keep pace with offensive improvements, and that it may not allow much in the way of reductions of other defensive systems like armor. Armor might be distributed differently, and more forms of reactive and controlled deformation armor will be used, but it’s pretty much indispensable for setting a minimal bar for an enemy weapon to be effective.

In all reality most wars tanks have fought in, they haven’t been that hard to destroy, but they were still vital because everything else dies even easier. Its only a few very recent wars that tanks really showed a high degree of immunity and were actually expected to survive numerous heavy caliber hits. In WW2 the Soviets alone lost something like 40 tanks per day on average, while fewer then that number total have been lost in five years in Iraq.

[Darth Raptor]

How about no, what you want a thread to be about it not what it has to be about. The thread is in Sci Fi, not Fantasy, and it asked if a certain mecha concept was viable, a question which has been answered. It did not ask to justify mecha by whatever means possible.

But it totally asked to descend into Mecha Bash Fest #9573. God fucking forbid we cover new territory with things people haven't read umpteen thousand times before on this very board and in this very forum; which is, hilariously, Warhammer 40,000 and Change. No, clearly, OSF is only for diamond-hard science fiction.

But if you’re going to justify them by any means necessary, then why the fuck even bother? Name any reason you want and it’s just as meaningful as any other when you’re forcing the scenario to fit a conclusion. Whatever specific excuse you could up with going to be scenario dependent, generalizations are more irrelevant then ever.

But "no they can never work ever under any circumstances STOP HAVING FUN" is totally poignant and helpful! Thanks!

What genre? What established existence? ‘tossing this idea around a while back’ is now a genre which MUST have mecha?

Lol, whut? Science fiction is among the biggest of tents and, arguably, a useless classification besides. The OP wants to write about mecha, and was under the woefully mistaken impression that he'd found an actual use for them. While swiftly disabused of this notion, it doesn't necessarily kill any and all interest. Not any more than Relativity deep sixes space opera.

[Sidewinder]

You will NEVER get a humanoid military vehicle to work without a large amount of wanking. Seriously, why bother with giving a mecha minimal armor so it'll be light enough to fly, when the godlike level of technology necessary to build the mecha in the first place will likely make antigravity engines powerful enough to lift a tank (or a heavily armored mecha) feasible?

Note: I don't include exoskeletons like the power suits of 'Starship Troopers' in that category because unlike the WAY TOO BIG to be practical mecha (cough! Gundams! "mobile suits" my ass! cough!), exoskeletons are worn like body armor to increase the mobility and/or strength (for carrying armor, weapons, battlefield surveillance radar and other specialized equipment, for moving a tree that's blocking a road) of a human infantryman, so it has greater practical value.

How do you personify a tank's movements, anyway? With mecha, you can imagine moving your arms and the machine will move its arms.

There's a dilemma in using direct neural interface to control mecha. On one hand, controlling a machine with two arms and 2+ legs is difficult enough BEFORE you include everything else a pilot needs to control in a military vehicle, e.g., the powerplant, sensors, weapons, communications, and mundane things like engine temperature, oil temperature and pressure, tire pressure (for a bipedal robot, this would probably be ground pressure and/or balance), etc., to the point where NOT using direct neural interface doesn't seem to be an option. On the other hand, there's a risk the pilot's idle thoughts will make the mecha do something regrettable, e.g., the computer interpreting a grunt's dislike for a glory-seeking commanding officer as an order to shoot the commanding officer.

When controlling a tank... can you turn the treads by... imaginarily clenching your sphincters?

Since the treads are a tank's means of mobility, it'll be easier to train the pilot to mentally link that to a human's means of mobility, i.e., his or her legs.

Hmmm... Imagine giving a T-34 one of those Gundam wings and giving it the same color schemes as one of those Gungans. Gundam, I mean.

As the flying T-34 and the flying Panzers duel in space, their tank commanders shall have battle philosophies! Rommel will be enigmatic, he will have an iron mask or something, to go with his flowing beautiful blonde hair. Erwin Rommel - Desert Bishonen!

Field Marshall Zhukov is going to cry manly tears while totally eviscerating his Space Panzer, though.

Let's just forget about the angsty emo "By chance, I got in the cockpit of a mecha, and even though I'm a civilian without any military training, I'm magically able to beat veteran pilots," "Why are we fighting each other? Can't we all just get along?" bullshit with pilots under the age of consent, i.e., any and all mecha pilots under the age of 19 (it'll likely take 1+ years to competently train a mecha pilot).

[Coyote]

Really, Star Wars already did it anyway-- the OP, that is. The Seperatist "Vulture" fighters were light walkers when landed; and leapt up to transform into fighters for combat ops.

Of course, they were full droids, not manned craft, and when they leapt up it was frequently in an environment where gravity was either not an issue (outside the cruisers) or where it could be controlled (and reasonably be expected to be controlled) such as inside the launch bay of the CIS battleship.

It was said earlier-- if a person wants a story with mecha, go for it and be happy. But don't try to rationalize or justify it by making it "real". If realism weighs in so much, then make a walking 'bot that is at most about the size of a small car and is used to ferry supplies or heavy weapons, ammo, or casualties, because that's about as far as it'll go, realistically. Anything bigger would be creamed by a tank or RPG, and as these things get more and more expensive, operating countries will be less and less inclined to use them for anything other than special ops with a potential high rate of return for the cost of the 'bot.

[FOG3]

Quite frankly, mecha are more realistic than anti-gravity. At least the former is possible, if wildly impractical. Also, the only two justifications for giant, humanoid robots (multiped tanks have real uses) are also the most compelling. Ideally, a power would field mecha because:

1) The humanoid configuration interfaces readily with the pilot, requiring minimal cross-training from infantry. Although this precludes the kind of fighter cockpit schemes you normally see, and begs the question of why there's a pilot at all if their neural networking is that good (and there are actually ways of addressing that, namely security).

Despite considerable research into the area all data points to that not really being possible. Moving a mouse pointer, is about it and even that doesn't actually require a implant, just a little training.

Even if you could, seems as how your average joe is not a Buddhist monk in terms of mental discipline it'd be borderline worthless, especially given what you could do with just a simple helmet mounted sight, HUD, and steering on a tank or similar vehicle.

[Admiral Valdemar]

Despite considerable research into the area all data points to that not really being possible. Moving a mouse pointer, is about it and even that doesn't actually require a implant, just a little training.

Even if you could, seems as how your average joe is not a Buddhist monk in terms of mental discipline it'd be borderline worthless, especially given what you could do with just a simple helmet mounted sight, HUD, and steering on a tank or similar vehicle.

You've somehow seen all future history of neural networking and concluded that moving a pointer circa 2008 is the best we'll get? By that logic, I propose we'll never get computers more powerful than the Intel Dual Core. Aside from that fact, that I can control my limbs by thinking about it kind of refutes your point. Anything that my brain can do now can, feasibly, be emulated via a transducer through a computer to control a bigger, more metallic and nuclear powered version of myself. With guns.

You know what's better than a human interface? A non-human interface, because the human isn't in the picture and an A.I. is instead.

[Sea Skimmer]

You've somehow seen all future history of neural networking and concluded that moving a pointer circa 2008 is the best we'll get? By that logic, I propose we'll never get computers more powerful than the Intel Dual Core. Aside from that fact, that I can control my limbs by thinking about it kind of refutes your point. Anything that my brain can do now can, feasibly, be emulated via a transducer through a computer to control a bigger, more metallic and nuclear powered version of myself. With guns.

Your brain can make your legs do useful things only through a feedback loop. Sure you want to wire a computer into your brain to give you feedback like that? I know I wouldn’t. If we can do that, the next step is brain hacking and adware installed into ones retinas… not an easy road to go down.

[Admiral Valdemar]

Of course, that comes with its own problems, but my point was that moving a cursor was not the end of it. The neural uplink could be used, as voice is, for complementing a traditional HOTAS like arrangement with sub-routines controlling other aspects. One could likely protect from the flawed fiction feedback effects anyway with circuit breakers and firewalls to avoid any nasty EW attacks (or just set the system to autistic and block all other sensory inputs).

Or one could avoid that by not having such a vehicle and using robotics instead. Hell, have biological brains used in cybernetics if dedicated synthetic AI is too hard. It's at least doable to an extent now even.

[Darth Raptor]

The traditional cockpit and joystick setups must be so completely, gloriously automated that the pilot is just essentially along for the ride- there to ensure that the unit continues to fight and for the proper side, most likely. Adequate neural networking comes with adequate brain mapping. In either case, it begs the question of why there's a pilot at all. If you're that worried about EW and you absolutely NEED your units to have human levels of intelligence and autonomy, your pilots could download copies of their consciousness into their machines and resynchronize if/when the unit returns. This is the method I use for both space fighters and mecha; in both cases the "cockpit" is just a brain-sized, biomorphic computer in the heart of the machine. That way, you can have your cake and eat it too. Loses don't equal fatalities, just forfeited experience, and it lets you avoid the (admittedly real) hazards of completely automated weapon systems.

[Teleros]

I was tossing this idea around a while back for a type of mecha that would be at least quasi-plausible for a "realistic" sci-fi warfare setting, and I'd like some criticism on it.

As has been said, your best bet if you want a realistic mecha is to go the powered armour / robot route. When I was a kid there used to be an old TV series on called Exosquad, which used "Exo-frames" - basically powered armour suits - rather than the giant robots you see in Gundam etc. Now the "Exo-frames" had their own problems mind you (horribly exposed pilots for one), but the concept is IMHO easier to rationalise than 20ft mechas and the like. The justification for their development was fairly believable too, incidentally:
1. Originally used in construction
2. Jury-rigged during the first war for combat
3. Were successful, albeit in part because the opposition wasn't that good
4. Became widely adopted and upgraded (and perhaps the top brass weren't thinking completely rationally - see point 3)
5. By the time the series starts, they're all over the place in the military, with various specialised models etc as well.
There's a good fan site of the series HERE BTW.


Another idea that might make large mechas more viable though would be some sort of shielding: if shields replace armour as the primary means of defence, then you'll have levelled the playing field somewhat - as has been said, tanks can generally be better armoured than mechas, but an energy shield can negate this advantage (mostly). Of course you'll still have plenty of problems (large profile, more easily detected reactor etc etc etc), but if your mecha designers can say "it's as tough as the latest in MBTs" it'll make it easier to get their machines into production.

In terms of the OP's idea of a small, lightweight mecha though... it just seems like a very expensive, easily damaged target . Really, it would be best to have multiple different vehicles rather than 1 trying to do all these various jobs. For example, if I was able to insert some sort of vehicle into battle from orbit, I'd go for something really hard-hitting - the enemy would have very little time to respond before my dropships, gunships or what have you are hitting them where it hurts.

[Sarevok]

Another idea that might make large mechas more viable though would be some sort of shielding: if shields replace armour as the primary means of defence, then you'll have levelled the playing field somewhat - as has been said, tanks can generally be better armoured than mechas, but an energy shield can negate this advantage (mostly). Of course you'll still have plenty of problems (large profile, more easily detected reactor etc etc etc), but if your mecha designers can say "it's as tough as the latest in MBTs" it'll make it easier to get their machines into production.

How would you fit a heavier shield system into an unstable platform like a mecha than a tank chassis which is proven to haul 70 tons across the battlefield unimpeded ?

[FOG3]

Despite considerable research into the area all data points to that not really being possible. Moving a mouse pointer, is about it and even that doesn't actually require a implant, just a little training.

Even if you could, seems as how your average joe is not a Buddhist monk in terms of mental discipline it'd be borderline worthless, especially given what you could do with just a simple helmet mounted sight, HUD, and steering on a tank or similar vehicle.

You've somehow seen all future history of neural networking and concluded that moving a pointer circa 2008 is the best we'll get? By that logic, I propose we'll never get computers more powerful than the Intel Dual Core. Aside from that fact, that I can control my limbs by thinking about it kind of refutes your point. Anything that my brain can do now can, feasibly, be emulated via a transducer through a computer to control a bigger, more metallic and nuclear powered version of myself. With guns.

Okay boy, try to pay attention this time. The neurologists have done the brain studies, and you know what they really found? Human brains aren't a standardized machine built to ANSI specs. So you tangent-man.

If the talk about Buddhist monk mental discipline was just beyond you, you honestly clearly don't pay enough attention to be worth the time.

You know what's better than a human interface? A non-human interface, because the human isn't in the picture and an A.I. is instead.

And you comment on that in response to my post because? Hey tangent-man, did I mention a neural interface setup being refuired to trump the theoretical neural interface being put out in supports of mecha? Did I? No?! Then what the heck are you wasting my time acting like a 5 year old about, tangent-man?

You got anything to contradict that a bloody WW2 era targetting computer such as mounted on your doctrinally expendable DD was better then manual, even without the extra complexity of the human form factored in? That HUDs don't work? The Human Factors Engineering has a big lapse in capability? That the DARPA challenge for self-driving vehicles didn't happen, and we have functional prototypes now? That it's a good idea to have a guy running on a treadmill in a cockpit so the mecha can mimic it?

Come on tangent-man, do you really have anything beyond "it was cool when the did it in *insert title here*?" You want to smart off, why don't you bring something of substance to the table?

[GrandMasterTerwynn]

Another idea that might make large mechas more viable though would be some sort of shielding: if shields replace armour as the primary means of defence, then you'll have levelled the playing field somewhat - as has been said, tanks can generally be better armoured than mechas, but an energy shield can negate this advantage (mostly). Of course you'll still have plenty of problems (large profile, more easily detected reactor etc etc etc), but if your mecha designers can say "it's as tough as the latest in MBTs" it'll make it easier to get their machines into production.

Ahahaha . . . no. Just no. If you can create an energy shield, then you can wrap one just as easily around a tank as you can a wank . . . I mean mecha. Of course, this energy shield will have to dispose of the same quantity of energy as the armor does, implying some sort of large energy sink/disposal system, along with the doubtlessly large reactor which will be required to power the energy shield. (Unless, of course, you intend to horribly break thermodynamics. At which point, you'd might as well stop pretending that you care about feasibility and realism and have your mecha driven by wizards and powered by mana.) All of this kit would be perched precariously atop what amounts to motorized stilts several meters high . . . meaning that your mecha is now a giant walking bomb.

And, of course, the tank could mount both energy shields and armor, negating any advantage the mecha might've had.

[Admiral Valdemar]

Okay boy, try to pay attention this time. The neurologists have done the brain studies, and you know what they really found? Human brains aren't a standardized machine built to ANSI specs. So you tangent-man.

If the talk about Buddhist monk mental discipline was just beyond you, you honestly clearly don't pay enough attention to be worth the time.

Sorry, was there a point there, like, something refuting my point? The human brain doesn't have a UNIX system or USB ports? SHOCK HORROR! You are familiar with the fact that primates using robotic arms have been documented in several studies, yes? The technology doesn't require a Buddhist monk, I'm afraid. Any old monkey can do it.

And you comment on that in response to my post because? Hey tangent-man, did I mention a neural interface setup being refuired to trump the theoretical neural interface being put out in supports of mecha? Did I? No?! Then what the heck are you wasting my time acting like a 5 year old about, tangent-man?

Actually, I moved on from your post, hence the new paragraph. But it is quite funny watching you give me a cute name and reply with nothing much.

You got anything to contradict that a bloody WW2 era targetting computer such as mounted on your doctrinally expendable DD was better then manual, even without the extra complexity of the human form factored in? That HUDs don't work? The Human Factors Engineering has a big lapse in capability? That the DARPA challenge for self-driving vehicles didn't happen, and we have functional prototypes now? That it's a good idea to have a guy running on a treadmill in a cockpit so the mecha can mimic it?

Come on tangent-man, do you really have anything beyond "it was cool when the did it in *insert title here*?" You want to smart off, why don't you bring something of substance to the table?

Hilarious and of questionable content. Somehow my pointing out the lack of true A.I. means I'm using a movie or book as evidence, and clearly because we can't do something today thanks to the infancy of the technology, it must be totally impossible (despite there being no objective reason for machine intelligence being undoable).

Actually, you should check the DSTL challenge for autonomous recce vehicles this year the MoD put together. They had multiple units go to a test town, identify potential targets and class their threat levels for friendlies, then return to base.

Not that even these feats matter as much, because we have fully functional drones in active combat already, which quite easily support my whole damn point. Aside from mechas being fucking stupid, the technology to make them at least less stupid by removing the human factor is not only possible, it's in service! And if this is of questionable use, then that would be because mecha are big walking targets. There's a reason the Black Knight prototype is a tank and not a 15 metre tall armoured man.

Feel free to point out where a human would excel beyond a human level machine though. You'll notice this time that it's a hypothetical, funny name calling man.

[RedImperator]

It was said earlier-- if a person wants a story with mecha, go for it and be happy. But don't try to rationalize or justify it by making it "real". If realism weighs in so much, then make a walking 'bot that is at most about the size of a small car and is used to ferry supplies or heavy weapons, ammo, or casualties, because that's about as far as it'll go, realistically. Anything bigger would be creamed by a tank or RPG, and as these things get more and more expensive, operating countries will be less and less inclined to use them for anything other than special ops with a potential high rate of return for the cost of the 'bot.

If you insist simultaneously on mechas and realism, the best you could do is try to write a realistic style story. The Big Media example of this is nBSG, which despite the presence of space opera tropes like space fighters, FTL, and artificial gravity, goes a long way towards feeling realistic by getting the little details as close to life as they can. So the FTL drive is broken...and the chief engineer fixes it by turning a valve with a pipe wrench. The chatter between the fighter pilots and the mother ship is modeled on the chatter between aircraft carriers and their planes.

So to extend this example to mechas, the writer might do extensive research on armored formations and tactics, the details of military life, and the function of real-life weapons, and simply plug mechas into the roles played by tanks. Rather than call attention to the inherent silliness of mechas by trying to rationalize them, just go ahead and insert them into a scenario that otherwise stays as close to the real world as possible.

[Admiral Valdemar]

There are more than a few anime series where mechas are portrayed in a fairly realistic setting, with only one or two little oddities (aside from the hulking walking machines) interfering with that illusion. Gasaraki springs to mind, especially given it seemingly predicted the Iraq invasion to boot. We'll ignore the stupid spiritual crap later on and Japan defeating the USA.

Despite the outlandish aesthetics of Gundams, the series they take place in are, more or less, quite believable with the scientific elements like nBSG, with only a few MacGuffins used to allow mechas to be used e.g. Minovski particles. The latest Gundam 00 incarnation even used an Earth modelled on a possible future variant of our time line, rather than a totally made up Earth with new continents, people and history.

Nothing to stop a person making such a story and have it work. If the idea of mecha insults you, then you won't bite. Otherwise, it can be just as compelling as a Bolo story (and even they use giant walkers from time-to-time).

[Sea Skimmer]

Nothing to stop a person making such a story and have it work. If the idea of mecha insults you, then you won't bite. Otherwise, it can be just as compelling as a Bolo story (and even they use giant walkers from time-to-time).

Yup, certainly is, which is why I made the point that its pointless to start listing reasons to use mecha in a vacuum like this thread. If you have a good military story it will be primarily about people because war is about people, not technology, and you can insert mecha for whatever reason or not reason you want and it will work or fail on the merit of its overall quality. If you include a five paragraph essay about how the mecha came into being via convoluted reasons… that wont make good writing. If one really wanted such a thing, it should go a in a separate fact file.

Count me as officially unimpressed and uninterested in the Bolo books BTW, for various reasons.

[Admiral Valdemar]

Yup, certainly is, which is why I made the point that its pointless to start listing reasons to use mecha in a vacuum like this thread. If you have a good military story it will be primarily about people because war is about people, not technology, and you can insert mecha for whatever reason or not reason you want and it will work or fail on the merit of its overall quality. If you include a five paragraph essay about how the mecha came into being via convoluted reasons… that wont make good writing. If one really wanted such a thing, it should go a in a separate fact file.

Well, yeah, that goes without saying. No one is interested in a textbook discussing the merits of a technology that is included only for the interest factor. You can safe that for an appendix if you want to detail things that would only look like out-of-place exposition in the story. A lot of sci-fi suffers from focusing too much on discussing the technology or describing planets or societies far too in-depth and losing all semblance of pacing and plot. So did Tolkien, in fact, who sorely needed an editor and suffered my lack of readership because of it. Do it well, though, and you can throw in a giant mechanical Kool-Aid man and keep the readers hooked. In fact, someone should write that novel.

Count me as officially unimpressed and uninterested in the Bolo books BTW, for various reasons.

I've only read some of the stories and they vary greatly in their quality. My favourite is still the one with Hector, a badly damaged Mk. XXXIII Hecate model, defending refugees trying to get off planet from some creepy Borg-esque ravagers who enslave the human colony and work them to death, or until they cut them up and use their organs for spare parts. The human factor is still there in oodles, while other Bolo stories are simply a few fights between a Bolo and an alien vehicle with nothing else tying the thing together, so it reads like someone's STGOD wanking more than anything. Sure, good fight scenes are necessary in a story, just some of the stories are only fight scenes, with the minimal setting up involved. Bolo Rising doesn't even have the tank power-up to use until nearly halfway through.

[Teleros]

How would you fit a heavier shield system into an unstable platform like a mecha than a tank chassis which is proven to haul 70 tons across the battlefield unimpeded ?

If you've developed a mecha in the first place you'll presumably have some idea as to how to balance the thing . Yes you're right that this will present problems - that's why I included all those qualifications in my post in the first place - I agree that mechas aren't realistic as military vehicles, but if you are trying to fit them into a universe, let's think up reaons as to why or how they could plausibly be in there.

Ahahaha . . . no. Just no. If you can create an energy shield, then you can wrap one just as easily around a tank as you can a wank . . . I mean mecha. Of course, this energy shield will have to dispose of the same quantity of energy as the armor does, implying some sort of large energy sink/disposal system, along with the doubtlessly large reactor which will be required to power the energy shield. (Unless, of course, you intend to horribly break thermodynamics. At which point, you'd might as well stop pretending that you care about feasibility and realism and have your mecha driven by wizards and powered by mana.) All of this kit would be perched precariously atop what amounts to motorized stilts several meters high . . . meaning that your mecha is now a giant walking bomb.

As opposed to a giant bomb on wheels / treads / repulsorlift / whatever . In other words, the same problems with the shield generator would face both a mecha and a tank - with the exception that, as Sarevok also noted, the tank is a more stable platform.

And, of course, the tank could mount both energy shields and armor, negating any advantage the mecha might've had.

Depends on the firepower of most weapons vs the quality of the armour, plus the weight & size of both armour & shield generator.

So to extend this example to mechas, the writer might do extensive research on armored formations and tactics, the details of military life, and the function of real-life weapons, and simply plug mechas into the roles played by tanks. Rather than call attention to the inherent silliness of mechas by trying to rationalize them, just go ahead and insert them into a scenario that otherwise stays as close to the real world as possible.

Sure, but you'd expect there to be some reason as to why they're used. As Sea Skimmer said, I wouldn't expect half a chapter on why they are there - I'm sure you could easily fit it into a sentence or two. Myself, I think cultural reasons plus some technology that doesn't make them completely outclassed by traditional vehicles is probably easiest (hence my point about shields) - even if a country's defence minister was hooked on Gundams and the like, I doubt very much that the rest of the government, let alone the military, would let him get away with giant walking robots just for cultural reasons.

[Commander 598]

...even if a country's defence minister was hooked on Gundams and the like, I doubt very much that the rest of the government, let alone the military, would let him get away with giant walking robots just for cultural reasons.

Well, obviously anyone trying to realistically advocate GIANT walking robots as a weapons platform in any vaguely near future Earthbound scenario should probably have their head examined, however keep in mind that they may not necessarily be "giant".

[GrandMasterTerwynn]

Ahahaha . . . no. Just no. If you can create an energy shield, then you can wrap one just as easily around a tank as you can a wank . . . I mean mecha. Of course, this energy shield will have to dispose of the same quantity of energy as the armor does, implying some sort of large energy sink/disposal system, along with the doubtlessly large reactor which will be required to power the energy shield. (Unless, of course, you intend to horribly break thermodynamics. At which point, you'd might as well stop pretending that you care about feasibility and realism and have your mecha driven by wizards and powered by mana.) All of this kit would be perched precariously atop what amounts to motorized stilts several meters high . . . meaning that your mecha is now a giant walking bomb.

As opposed to a giant bomb on wheels / treads / repulsorlift / whatever :P . In other words, the same problems with the shield generator would face both a mecha and a tank - with the exception that, as Sarevok also noted, the tank is a more stable platform.

The tank would also keep the shield generator in a low-profile vehicle that's wrapped in armor. Unlike the mecha, where it's sitting several meters off the ground in a lightly armored shell, and let's not forget that the mecha's most vulnerable fiddly-bits can't be that well-protected, lest the mecha be unable to move.

And, of course, the tank could mount both energy shields and armor, negating any advantage the mecha might've had.

Depends on the firepower of most weapons vs the quality of the armour, plus the weight & size of both armour & shield generator.

If you've got weapons capable of going through armor like a plasma torch through butter, and you're reliant on the energy shield, you're still better off building tanks. That low profile means less volume to shield, for one (that, and the standing mecha is going to be a most attractive target.) For another thing, those overcomplicated mecha aren't going to be very cheap to replace when their shields go down and they get chopped off at the waist. Granted, the tank isn't going to be all that cheap to replace either, but for vehicles of equivalent tonnage, the tank will still carry more weaponry than the mecha, and would have greater return per unit of money spent.

[RedImperator]

So to extend this example to mechas, the writer might do extensive research on armored formations and tactics, the details of military life, and the function of real-life weapons, and simply plug mechas into the roles played by tanks. Rather than call attention to the inherent silliness of mechas by trying to rationalize them, just go ahead and insert them into a scenario that otherwise stays as close to the real world as possible.

Sure, but you'd expect there to be some reason as to why they're used. As Sea Skimmer said, I wouldn't expect half a chapter on why they are there - I'm sure you could easily fit it into a sentence or two. Myself, I think cultural reasons plus some technology that doesn't make them completely outclassed by traditional vehicles is probably easiest (hence my point about shields) - even if a country's defence minister was hooked on Gundams and the like, I doubt very much that the rest of the government, let alone the military, would let him get away with giant walking robots just for cultural reasons.

I disagree. Look, mechas are nonsense. Period, full stop. Any attempt to justify them is just going to call attention to the fact that they're nonsense. So don't try to justify them. Have enough confidence in your writing to believe your readers will be willing to suspend their disbelief and enjoy the story. Because the fact is, if you're good, most of your readers will go along with you. The ones that don't, on account of the mechas, aren't going to be convinced by some weak-tea justification anyway, so why call attention to the problem? And if you feel you need to put that paragraph in there because you, the writer, need to be convinced, then your story is already in trouble; if you don't believe in your story, for damn sure the audience won't.

[Covenant]

Minor aside, it's also usually a good idea to have energy shields obey the laws of conservation of momentum, so if you fired a heavy, high-velocity shell into a shielded mecha the shell will hit the shield and splatter due to the fact the shield is absorbing the impact--and that then transfer some of the momentum to the generator, which is then transferred to the bracings. Having a light plastic and composite mecha will mean very weak bracings, to the point that a solid hit from a tank slug might be stopped by the shield, but rip the generator free of it's bracings and knock a big hole in the mecha.

[Sea Skimmer]

Minor aside, it's also usually a good idea to have energy shields obey the laws of conservation of momentum, so if you fired a heavy, high-velocity shell into a shielded mecha the shell will hit the shield and splatter due to the fact the shield is absorbing the impact--and that then transfer some of the momentum to the generator, which is then transferred to the bracings. Having a light plastic and composite mecha will mean very weak bracings, to the point that a solid hit from a tank slug might be stopped by the shield, but rip the generator free of it's bracings and knock a big hole in the mecha.

That’s actually a major issue with real life armor too, even when everything is built of metal. During the studies for FCS for example it was determined that it would simply not be possible to build a 20 ton AFV that was proof against 120mm tank shells, because no matter good advancements in armor technology might be, the structure of the vehicle was just going to crumple under the hit. That would then result in the armor tearing, and the projectile would inflict perhaps even more massive damage then a clear perforation would have.

This was also a serious issue for the designers of battleships, as one can image the battering effect of a 1 ton shell hitting at as much as mach 2.5 is quite massive. Eventually complicated systems of keying together armor plates were adapted, along with REALLY good bolts, and separate structural backing plates behind the armor plates, but nothing was ever completely satisfactory about it.

Weakness of structure also keeps explosive reactive armor off of light AFVs. The armor will simply be dished in or torn by the detonation of the ERA.