Lasers as lethal anti personal weapons.

[The Jack]

So I've bothered the RL armour, tactics and weapons thread, not realising this part of the site exists, so forgive me for repetition.

In the setting I'm using the enemy have developed resistances (or other means of defeating) conventional weaponry, poisons, and fire (specifically fire, not blasts of heat, though I'd count burning thermite or phospherous as fire, it's magic)
The Allies are limited when it comes to vehicles, but can be augmented increased strength, increased stamina, and some can be the size of a pony/horse (and sometimes even a rhino) ; basically, weight isn't the issue it would be on normal soldiers, but it's still a concern. Heat dispersion should be thought of as "stopping the gun from melting", primarily, although "not cooking the wielder" is a nice bonus (protective clothing or heat resistant powers can make up for much)

So I want to know how much energy can be put through a weapon of X size given the limits of emitters.

What I've currently got is thus
From Carl
3 megajoules a shot is a safe estimate for for instant, explody flesh

The best rechargeable batteries have an energy density per unit volume of about 2.2MJ per litre, or about 4.4 mj per 2L bottle of coke, and a weight density fo just 0.79MJ per KG, even a 100KG backpack is only going to give you around 30 shots, and whilst they're going to be destructive. Hollowpoint assault rifle ammo will probably be about as effective against normals.
My garbage maths (and penchant for nice rounding) gives me something like this.
18kg per 5 shots, 33 litres.
54kg, 15 shots, 100L
110kg, 30 shots, 200L

Now that's exciting because if you can put it on a backpack, it's nicely wearable by the characters I've got in mind, but what about the weapon iteself? How big do you need everything to deliver 3mj of laser from an armcarried pointy thing? (remember; potentially big arms)

If it can't be put on a backpack, due to power concerns, the big guys could probably still use it.
Also, what'd be the rate of fire? Might need to be limited to stop the thing melting.

[SpoonR]

Define fire, unfortunately. And more detail on their defenses. You are right to differentiate fire and heat though.

In general terms, I would say fire is a reaction (usually but not always chemical) that involves shuffling electrons and electron bonds around, and produces heat as a byproduct. Occasionally also pressure waves (aka explosions) So thermite, white phosphorous, raw sodium are all fire. Fire needs an oxidizer (something to strip electrons) but not necessarily oxygen.

Which gets us to lasers. A laser cutter or weapon works by a combination of vaporizing and oxidizing the target to produce things like tiny explosions and plasmas. In other words, a cutting laser works by setting a tiny area on fire.

Now, heat in this context is basically vibrating molecules. Whatever is incoming isn't powerful enough to make electrons fly off, but is able to give energy to the atom or molecule as a whole. That's why heat sources are usually infrared or microwave based (wiki ionizing vs nonionizing radiation)

I think that gives you three options for heat. 1. Giant microwave like the army is currently developing. Drawback is it is huge and/or slow (walking through the beam of a high-power radar can cook your eyeballs in minutes, not sure how long to cook brain matter, but afaik at least hours to do anything permanent to the rest of your body) Walking around with a cell tower equivalent on your back could be difficult. 2. A laser targeted at the frequency ofa specific chemical bond - laser gets really well absorbed by that molecule which makes it heat up a lot. Probably still rather slow, and could be defeated by a different color sunscreen.

3. Dump a lot of heat on the target, using a good heat transfer medium. So, question, you count burning thermite as fire (which I agree with). But, what if you put the thermite inside a thermite-proof case? The thermite reacts, but the fire is trapped in the case and only the heat can come out. Would that count as heat for you? What about, say, dumping a vat of molten steel on their head? Exact carrier doesn't matter as long as it can transfer the heat (a regular soldering hot blower reaches 750F, a mil-spec one could be nasty), but I'm partial to a "squirt gun" firing molten metal. Or a flamethrower firing something sticky.

So tldr, a real laser won't do what you want.

That said, I originally thought the title was "T"aser. And a big blast of electricity going through someone's innards could produce a lot of heat in there, and with some handwaving could give you the visual of a laser. Say, metal needles (with nearly invisible wire atttached) being propelled by a laser vaporizing the propellant end of the needle, then the wire carries enough current that it glowingly explodes, and you have a dead enemy with smoke coming out. For this, you would have a backpack of supercapacitors instead of batteries, and the fire rate would be determined by your charging rate. Solar panel on the backpack? Probably hours minimum. Mini fission plant or efficient gas engine? From a nonphysicsy, how I expect a story to go, I would think 30 to 60 seconds. Anything close to a modern gun firing rate would feel funny. Heat dispersion not a big thing since the part that gets hottest is the wire and that is expended every shot. Off the cuff, 3 MJ, through a wire let's say 1/10th second, so 30 MW. Pulling numbers that feel good, that would be 1000 amps @ 30,000 volts.

I know you said no poison, but what about 'all your problems at once via chemistry'.
https://en.wikipedia.org/wiki/Chlorine_trifluoride


Now, I'm going to step back to assuming somehow lasers are ok. What you're basically talking about is a laser cutter.
https://en.wikipedia.org/wiki/Laser_cutting
Handwavium optics could account for a useful (> 1 inch) range. Pulsed laser would generally work faster, but I'm not sure how to combine joules, watts, pulse width, and "what makes flesh splodey" to figure out the numbers. Lots of heat to disipate no matter what, 10% efficiency would I think mean 9kW heat for 1kW weapon?
One of the best ways to get a high power laser without a building's worth of electricity is to go to single-shot chemical lasers.
https://en.wikipedia.org/wiki/Chemical_oxygen_iodine_laser
So now your backpack doesn't have batteries, it has capsules of toxic chemicals.

That... is probably less than helpful. I need to think about this some more, and maybe find an old textbook.

[pendell]

So I've bothered the RL armour, tactics and weapons thread, not realising this part of the site exists, so forgive me for repetition.

In the setting I'm using the enemy have developed resistances (or other means of defeating) conventional weaponry, poisons, and fire (specifically fire, not blasts of heat, though I'd count burning thermite or phospherous as fire, it's magic)
The Allies are limited when it comes to vehicles, but can be augmented increased strength, increased stamina, and some can be the size of a pony/horse (and sometimes even a rhino) ; basically, weight isn't the issue it would be on normal soldiers, but it's still a concern. Heat dispersion should be thought of as "stopping the gun from melting", primarily, although "not cooking the wielder" is a nice bonus (protective clothing or heat resistant powers can make up for much)

So I want to know how much energy can be put through a weapon of X size given the limits of emitters.

What I've currently got is thus
From Carl
3 megajoules a shot is a safe estimate for for instant, explody flesh
My garbage maths (and penchant for nice rounding) gives me something like this.
18kg per 5 shots, 33 litres.
54kg, 15 shots, 100L
110kg, 30 shots, 200L

Now that's exciting because if you can put it on a backpack, it's nicely wearable by the characters I've got in mind, but what about the weapon iteself? How big do you need everything to deliver 3mj of laser from an armcarried pointy thing? (remember; potentially big arms)

If it can't be put on a backpack, due to power concerns, the big guys could probably still use it.
Also, what'd be the rate of fire? Might need to be limited to stop the thing melting.

When I think of lasers I think of the airborne laser (https://en.wikipedia.org/wiki/Boeing_YAL-1), a test system designed in the 1990s to knock down ballistic missiles. There's also the Advanced Tactical laser (https://en.wikipedia.org/wiki/Advanced_Tactical_Laser) intended for use against ground targets. That puts out about 600 kilowatts. I don't know the exact power requirements to generate a 600 kilowatt laser, but it's bulky enough to need a large cargo plane, as opposed to a small fighter.

I think if you want a man-portable laser small enough to do this kind of damage, you're going to either need some very advanced miniturization technology (I understand there are ideas to replace chemical lasers with solid-state: Same bang in a smaller package) or you're going to need a great deal more power; man-portable fusion power pack, I think. Maybe Cold Fusion works in your universe?

Anyway, the reason such things aren't common in the real world is because in terms of delivering energy a laser is very inefficient compared to projectiles; the main time you really need a laser is when you need absolute precision, as when trying to hit a suborbital rocket or an artillery shell in flight (https://en.wikipedia.org/wiki/Tactical_High_Energy_Laser) . Against most targets of human size and velocity regular guns work just fine.


Respectfully,

Brian P.

[Anymage]

Don't do this. Just what people are saying about the energy requirements hints at a huge can of worms that you'll be opening. If you say "this is our real world, with our real physics, except that secret labs have perfected medicine and materials science and whatnot to the point where we can have cyborgs toting laser cannons", players will quickly wonder what else they can do with such super energy storage devices. You're just asking for people with a baseline understanding of science to try breaking your setting.

You have two options. One to go all over the top and embrace Rifts. It doesn't matter if the enemy is immune to any conventional damage when you're wearing power armor that can shoot hundreds of flechettes at supersonic speeds to turn them into red mist. The other option is to go hardcore black ops. Heavy military hardware can also mist whatever it hits, and sufficiently rich and driven people can get their hands on it. (You can try asking the god of war to make you immune to some of his favorite toys. Good luck with that. Spirits, especially powerful ones, should be alien.) Look into some of the things that various power players in The Dresden Files can bring to bear against heavy opposition. People faced with an angry werewolf are still best off running and hoping it chases someone else instead. But traps, ambushes, returning with heavy ordinance, and straight up assassination have always been popular methods of taking down something bigger than you.

[Mechalich]

Don't do this. Just what people are saying about the energy requirements hints at a huge can of worms that you'll be opening. If you say "this is our real world, with our real physics, except that secret labs have perfected medicine and materials science and whatnot to the point where we can have cyborgs toting laser cannons", players will quickly wonder what else they can do with such super energy storage devices. You're just asking for people with a baseline understanding of science to try breaking your setting.

The energy requirements necessary to produce an anti-personnel laser weapon are not fantasy. They're a bit tricky - mostly as a result of how lasers deal damage - but not absurd. A vehicle mounted weapon - which can take advantage of much greater storage and heat dispersion resources - is absolutely a theoretically viable option if current trends continue for a century or so. There's a fairly detailed discussion of the technical aspects of this type of weapon Atomic Rockets (http://www.projectrho.com/public_html/rocket/sidearmenergy.php).

The real issue is you're talking about at least a century's worth of technological development in the relevant factors - laser, battery, power transference, etc. - all for the purpose of producing a weapon that is not going to possess significantly greater destructive power than an AK-47, with likely substantially reduced range (especially in battlefield conditions, combat environments tend to fill with dust and other airborne particulates, and that does horrible things to lasers). So the utility of such a weapon would be highly limited. Laser weapon emplacements might have utility over conventional firearms in certain ways. A machine gun like an M60 cannot be fired continuously without melting a barrel off, but a laser sitting on top of a subterranean cooling system and drawing on a municipal power grid potentially could. But you don't really need continuous short-range saturation fire unless you're fighting the Zerg or something equally crazy.

So in the situation introduced by the OP wherein the enemy has developed a resistance to conventional firearms, the general solution is to build better/specialized firearms to overcome said resistance, not try to switch to lasers. This is doubly true since at the end of the day a blaster type laser weapon is design to deal damage in a similar fashion to a firearm - by burning a hole through tissue as opposed to cutting one. So it's going to be a very rare scenario where a laser is going to be able to effectively injure an enemy a gun could not.

[Anymage]

The energy requirements necessary to produce an anti-personnel laser weapon are not fantasy. They're a bit tricky - mostly as a result of how lasers deal damage - but not absurd. A vehicle mounted weapon - which can take advantage of much greater storage and heat dispersion resources - is absolutely a theoretically viable option if current trends continue for a century or so. There's a fairly detailed discussion of the technical aspects of this type of weapon Atomic Rockets (http://www.projectrho.com/public_html/rocket/sidearmenergy.php).

I'm not saying that it's physically impossible. I'm saying that if the players can get their hands on supertech in what's supposedly a modern world game, they can turn around and use that supertech for all sorts of other uses.

Basically, not to mix gaming and "this works exactly like real physics" unless you really know what you're doing. Doubly so if you add "...unless you use magic, which can break physics where called on but otherwise assumes everything works the same.

[pendell]

How about a religious prohibition a la the Butlerian Jihad in Dune? In that setting, artificial intelligence is a fact of science, but no one creates them if for no other reason than it will bring the entire weight of the Imperium, Emperor and houses combined, if even one is brought into existence. Nuclear weapons are excluded from use by the same principle; everyone has them, but to use them will bring the weight of the entire rest of humanity down on the offender.

Respectfully,

Brian P.

[The Jack]

It's an ideological thing. I've already got monsters totting 20mm guns (granted, a far smaller leap. I'd be really interested in 30mm, but people have, in a way that I've found frustratingly inconclusive, told me it wouldn't work.)

Lasers are just... well, they're lasers. People who hunt down monsters aren't the sanest sort. They want lasers. If carl is right about the power, then we just need to worry about the emitter. And I could cheat at any point and go "Magic" but the closer we are to science the better.




Also how would I go about shooting burning liquid metal at people. That seems like itself would require huge machines and lots of power, but Note; using a metal that melts at a very low temperature, and which would be less effective than a flamethrower, isn't really worth it.

[Telok]

Also how would I go about shooting burning liquid metal at people. That seems like itself would require huge machines and lots of power, but Note; using a metal that melts at a very low temperature, and which would be less effective than a flamethrower, isn't really worth it.

If you want burnination and aren't too picky about how expensive the supersoaker ends up being I do suggest the fluorine route. Chlorine tirfluoride has already been mentioned (side effect: scalding hot clouds of hydrochloric acid) but elemental fluorine and FOOF are horrific in their own right.

Simply put fluorine is a better oxidizer then oxygen. Better to the point that you can set sand and ash on fire with it. Turns out it's possible to get metal to burn.

https://curiosity.com/topics/the-stupidly-dangerous-chemical-chlorine-trifluoride-can-make-anything-burst-into-flames-on-contact-curiosity/

[georgie_leech]

If you want burnination and aren't too picky about how expensive the supersoaker ends up being I do suggest the fluorine route. Chlorine tirfluoride has already been mentioned (side effect: scalding hot clouds of hydrochloric acid) but elemental fluorine and FOOF are horrific in their own right.

Simply put fluorine is a better oxidizer then oxygen. Better to the point that you can set sand and ash on fire with it. Turns out it's possible to get metal to burn.

https://curiosity.com/topics/the-stupidly-dangerous-chemical-chlorine-trifluoride-can-make-anything-burst-into-flames-on-contact-curiosity/

Chlorine trifluoride will burn asbestos for crying out loud. Fireproof pretty much isn't a thing as far as it's concerned.

[Caesar]

Why do people insist on doing real world physics to model their fantasy settings? A) You aren't going to get the math right. B) It doesn't matter anyhow. C) It's only going to limit your setting in a way you no longer have control over.

Want anti-personel lasers? Cool, now you have anti-personel lasers. Make them shoot however many shots you feel is balanced in your system's physics, ie the game mechanics.

[SpoonR]

Trifluoride over FOOD for the coolness factor "nazis thought it was too dangerous to use". Obligatory link for the nasty chemistry:
In the pipeline (http://blogs.sciencemag.org/pipeline/archives/category/things-i-wont-work-with)

Liquid metal is comparatively easy, since we know enough to do plenty of cool things now. (liquid sodium solar to electricity converters). You only really need one handwave - a really good insulator - and aerogel might work. The soldier has a backpack canister connected to the supersoaker. That's it. Now, their support vehicle or operating base needs the power source to do the melting, but with a good enough insulator you could go days or weeks between filling a tank, and the tank cooling off and the metal solidifying. (Hmm, a railgun that fires a bullet with enough velocity to melt during the flight would look pretty, not sure how much energy required though)

The fundamental problem with lasers is "they don't work that way". Or, "curse you physics!" Take the Hollywood "any car damage makes it explode in a fireball" myth, and increase the tall tale factor by a thousand or so.
Big lasers can't be very effiicent and can't really shrink*, little ones can't be very powerful. Very sensitive to alignment, whatever's in the air on the way to the target, if you can see the beam then the laser can't** kill anyone, hard to make it stay a laser over useful distance and even then hard to make it damaging except at a precise distance***, etc.
I'd summarize as: photons are really really small, and one photon with a lot of energy is still a really small amount of energy, and even a lot of photons is still tiny on the human scale, so it takes a lot of tricks to make it work as well as it does.

*A crystal (or liquid) laser needs more crystal to make more beam. And the longer the laser cavity the more power you can get. Those limits are hard to go round. The biggest lasers either have a lot of space for the beam path (fusion power research lasers) and/or burn a lot of extra energy to get all power into the beam on a single pass through the cavity (anti-missile laser)
** To see the beam, the laser has to be bouncing off something in the air (dust etc) which sucks power out of the beam. And, a powerful laser could have reflections harm the user.
*** If you focus the laser to a point for max burniness, or if you split the laser into twin beams, you can focus a laser enough to burn a single cell, and it will pass through tissue above and below without doing damage. Under the right conditions.
**** Re efficiency and heat dissipation. LED lightbulbs use less energy and make less waste heat than incandescent right? One problem with that, which would be worse in a laser LED like you might want in a gun. Less heat, but it is all concentrated in a tiny tiny area, the size of the diode. 75% of an LED bulb is there to get heat away fast enough to keep the diode from burning out. Scaling that up to lethal laser diode, oy.

Thinking about photon weight does give another idea though - basically the large hadron collider approach. Instead of firing a wee photon, shoot something huge like a gold atom. Ionize the atom, use a magnetic field to accelerate. Cyclotron gun.

Seconding or thirding Atomic Rocket as a resource where people have done these calcs. Take their calcs over my estimates.
http://www.projectrho.com/public_html/rocket/sidearmenergy.php#id--Lasers


Why do people insist on doing real world physics to model their fantasy settings? A) You aren't going to get the math right. B) It doesn't matter anyhow. C) It's only going to limit your setting in a way you no longer have control over.
Cause the OP asked. Also because unless you make it an ultra-black-box "magic lasers that no one understands and where if you separate the pieces the magic goes away", you open yourself up to unintended consequences, fridge logic, possibly losing versimilitude

[Anymage]

Cause the OP asked. Also because unless you make it an ultra-black-box "magic lasers that no one understands and where if you separate the pieces the magic goes away", you open yourself up to unintended consequences, fridge logic, possibly losing versimilitude

If you want to have a seemingly modern setting (from the OP's posts in other threads, he does), you have to compare the fridge logic of handwavium laser weapons vs. the fridge logic of assuming that people can reasonably access the energy storage tech to make man-portable laser weapons work. It's very much like how comic books fall afoul of all sorts of fridge logic when you ask why supergeniuses are making breakthroughs all over the place, but societal norms and Joe Average's experiences are practically identical to our world.

I'm enjoying the general thread. But there are plenty of times in games when pursuing scientific accuracy is indeed a fool's errand.

[The Jack]

Nah, just add social factors like
We got the knowledge to build this from sources/through means we'd very much like to keep secret, so it must be secret.
or
if the government knew we had this tech it would be seized/if civilians knew we had it there'd be too much outrcry. /we expect arrests.
or
This tech gives us an edge and so we can't carelessly do it on a big scale, unless it falls into the wrong hands.

and all of these are very relevant to the setting in particular. No "fridge" logic. Everything is justifiable.

[Caesar]

Cause the OP asked.

My point was obviously that the OP is wasting his time and probably lessening his campaign setting by asking the question in the first place.


Thinking about photon weight does give another idea though - basically the large hadron collider approach. Instead of firing a wee photon, shoot something huge like a gold atom. Ionize the atom, use a magnetic field to accelerate. Cyclotron gun.

Photon weight? They are massless. The problem with adding mass is that you add force interactions, so beam attenuation becomes a significant problem and operation requires hard vacuum conditions at a minimum. Electrons have one of the smallest interaction cross-sections, yet only a meter of air at 1 atm is enough to destroy coherency in a relativistic beam.

That said, rule of cool says you can have relativistic particle cannons used to ionize everything from hard-shielded onboard ship computers to the biological wetnets used to operate your front-line troops.

[gomipile]

If you want to have a seemingly modern setting (from the OP's posts in other threads, he does), you have to compare the fridge logic of handwavium laser weapons vs. the fridge logic of assuming that people can reasonably access the energy storage tech to make man-portable laser weapons work.

The OP isn't requiring man-portable laser weapons, according to the top post. What is asked about is allowed to be quite a bit heavier than that. I think that might make it more realistic.

[Bohandas]

That said, I originally thought the title was "T"aser. And a big blast of electricity going through someone's innards could produce a lot of heat in there,

Which was the main gimmick in the Sypon Filter videogame series

[Tyndmyr]

It's actually surprisingly hard to make man-portable lasers that instantly kill. Particularly for long ranges, as human movements are magnified over range. It's extremely difficult to focus on anything long enough to set it aflame. Blinding is comparatively easy, but actually killing? Ugh. Mirrors, smoke, dust, etc also present a concern. And if you get a super laser, thermal bloom is an issue. Nobody ever properly portrays the challenges inherent in making death rays.

A five watt laser can be purchased that is about the size of a lightsaber hilt/flashlight. You can scale upward from there, but it's somewhat short of linear, because of the added mass of heat management stuff you need to add. Even the five watt lasers suffer from some heating issues. Twenty of those would be a mere hundred watts, while being large enough to be quite awkward to wield, and needing a fairly significant amount of heat management. It might remain technically carryable, for a very brawny individual, but normally these are mounted somewhere.

Still, 100 watts, though not enough to make a person instantly explode, would be quite damaging. It can, for instance, engrave metal. Anyone getting burned is unlikely to remain still, but you could disable equipment fairly effectively with it, and setting someone's uniform on fire is still a bit awkward.

[Tvtyrant]

The US military has been working on vehicle mounted lasers for drone defense for a while as a cheaper alternative to using missiles. The advantage of shooting at drones or planes is they have very little cover to hide behind and have a more delayed reaction.

You could easily make it so the lasers are self-enforcing though. If everyone wears power armor sufficient to ignore bullets and grenades, but you can knock out the suits power with lasers then it could make sense (in the way Dune forces sword fighting via forcefields.)

[factotum]

If everyone wears power armor sufficient to ignore bullets and grenades, but you can knock out the suits power with lasers then it could make sense (in the way Dune forces sword fighting via forcefields.)

Or you could just use tried and tested anti-tank weapons that already exist and which don't require massive leaps in technology? That's always been my problem with the concept of super-soldiers in power armour--the armour on such a thing is not going to be as thick as the armour on a tank, because it has to fit on a human and be usable, so one regular grunt with a bazooka and HEAT ammo is going to really ruin your day.

[Knaight]

Or you could just use tried and tested anti-tank weapons that already exist and which don't require massive leaps in technology? That's always been my problem with the concept of super-soldiers in power armour--the armour on such a thing is not going to be as thick as the armour on a tank, because it has to fit on a human and be usable, so one regular grunt with a bazooka and HEAT ammo is going to really ruin your day.

That takes a fair bit more than one regular grunt with an assault rifle or shotgun though, and that's without getting into how bazooka rate of fire isn't great.

[Tvtyrant]

Or you could just use tried and tested anti-tank weapons that already exist and which don't require massive leaps in technology? That's always been my problem with the concept of super-soldiers in power armour--the armour on such a thing is not going to be as thick as the armour on a tank, because it has to fit on a human and be usable, so one regular grunt with a bazooka and HEAT ammo is going to really ruin your day.

Good luck hitting a person with a bazooka, which is inherently slow and inaccurate.

You might hit around the guy, but then the question is how much explosive are you chucking at him for it to be lethal? The US could deploy backpack nukes and flamethrowers but chooses not to because massive civilian casualties are considered detrimental to the mission.

[factotum]

Good luck hitting a person with a bazooka, which is inherently slow and inaccurate.

Depends how close you get, really--I bet a power-armoured dude would be reasonably easy to hit from 50 yards away. For that matter, since we *are* talking about thinner armour than a modern tank, would a regular anti-materiel rifle do the job? Those are plenty accurate. And all this is without considering than military designers would be working on anti-power-armour weaponry once power armour becomes a thing.

[wumpus]

Nah, just add social factors like
We got the knowledge to build this from sources/through means we'd very much like to keep secret, so it must be secret.
or
if the government knew we had this tech it would be seized/if civilians knew we had it there'd be too much outrcry. /we expect arrests.
or
This tech gives us an edge and so we can't carelessly do it on a big scale, unless it falls into the wrong hands.

and all of these are very relevant to the setting in particular. No "fridge" logic. Everything is justifiable.

Do you have any idea how big a bomb you could make by attaching a grenade to your laser gun and pulling the pin? And if the you have to keep the laser system secret, you have to do this every time to avoid capture, making it extremely clear just how powerful your energy source is.

Another critical element is that once a technology is known to be possible, R&D labs the world over will beeline to it if they know that it produces very real results (especially if they know it produces the results that they are interested in, and if you have enough "secret techs" that are very publicly used, most R&D labs will have at least one such tech they are interested in).

If the "enemy" suddenly has access to your "super energy source" that you refuse to use for anything other than lasers, you are suddenly in a heap of trouble (especially since the enemy has no need of lasers).

[LordEntrails]

Another critical element is that once a technology is known to be possible, R&D labs the world over will beeline to it if they know that it produces very real results (especially if they know it produces the results that they are interested in, and if you have enough "secret techs" that are very publicly used, most R&D labs will have at least one such tech they are interested in).
Absolutely this ^^

This is why "black projects" are black; unrecognized, untraceable, not shown in the light of day. "Secret" is not enough. Because as wumpus says, once your enemy knows something is possible, it's only a matter or a few short years until they reproduce it. Or sometimes much less if it's not a revolutionary technology. This is why black weapon projects are only used when the need is great enough, when their is not another weapons system that can accomplish the mission, or when the enemy is deemed to be on the cusp of discovering the technology, or a politician decides they need to sway public opinion (SR-71).

An example; stealth aircraft. Were black projects, only flew in the night, and were not acknowledged by the government (until a political decision). Once they were downgraded to top secret, the theories and concepts to create stealth aircraft were public knowledge within a few years, even if the actual plans and computer programs, etc were still top secret. And those organizations (countries) with enough money and will created their own stealth aircraft.

So, once your weapon is used, and their is a survivor or sufficient evidence of its use, your enemies will be after it full force. Not only in R&D, but in trying to capture their own sample. And they won't be sending their minions, they will be sending their elite forces.

[halfeye]

Good luck hitting a person with a bazooka, which is inherently slow and inaccurate.

You might hit around the guy, but then the question is how much explosive are you chucking at him for it to be lethal? The US could deploy backpack nukes and flamethrowers but chooses not to because massive civilian casualties are considered detrimental to the mission.

Backpack nukes are a very bad idea yes, but flamethrowers were in use in WW2, and very probably will be in any future war (unless a Geneva convention has banned them since then, which I don't remember hearing about, but then there's a lot I have heard about that I don't remember), they are not like civilian flame throwers which are for starting bonfires and destroying weeds, military flamethrowers throw a narrow stream of napalm quite a long way (fifty or sixty yards), they are not at all indiscriminate, though they are certainly nasty.

[Tvtyrant]

Depends how close you get, really--I bet a power-armoured dude would be reasonably easy to hit from 50 yards away. For that matter, since we *are* talking about thinner armour than a modern tank, would a regular anti-materiel rifle do the job? Those are plenty accurate. And all this is without considering than military designers would be working on anti-power-armour weaponry once power armour becomes a thing.
It does take some justification, because no one really knows where warfare is going to go.

For instance I personally think power armor is going to go hand in hand with mass deployed smoke screens (probably a mix of tear gas and vision impairment smoke) and using internal air and heat vision to pick out targets. Opposing forces tend to be low tech and lack answers to these problems.

A current issue that is easily resolved is thst type 4 armor is moving towards immunity to automatic rifle fire, due to the small calibers used to capitalize on the high rate of fire. This problem was actually resolved in wwII when snipers were issued explosive shape charge bullets for dealing with sniper vests at long ranges where bullets ran out of energy. Take the same bullet and stick it into a low velocity submachine gun and body armor immediately appears anemic.

[halfeye]

It does take some justification, because no one really knows where warfare is going to go.

For instance I personally think power armor is going to go hand in hand with mass deployed smoke screens (probably a mix of tear gas and vision impairment smoke) and using internal air and heat vision to pick out targets. Opposing forces tend to be low tech and lack answers to these problems.

A current issue that is easily resolved is thst type 4 armor is moving towards immunity to automatic rifle fire, due to the small calibers used to capitalize on the high rate of fire. This problem was actually resolved in wwII when snipers were issued explosive shape charge bullets for dealing with sniper vests at long ranges where bullets ran out of energy. Take the same bullet and stick it into a low velocity submachine gun and body armor immediately appears anemic.

I don't think tanks are going away any time soon. They're hard to destroy and low profile, an equivalent humanoid shape would be much easier to hit, and almost certainly not any harder to destroy once you did hit it.

[Tvtyrant]

I don't think tanks are going away any time soon. They're hard to destroy and low profile, an equivalent humanoid shape would be much easier to hit, and almost certainly not any harder to destroy once you did hit it.

I don't see where I said tanks are going away?

[halfeye]

I don't see where I said tanks are going away?

You probably didn't explicitly, but body armour leads to powered exoskeletons, leads to gundams or transformers or something silly, powered exoskeletons make a sort of sense for civilian/police use, but for military use up against real tanks they're a big "nope" to me. Mind you "technicals" make no sense to me either, so what do I know?

[Tvtyrant]

You probably didn't explicitly, but body armour leads to powered exoskeletons, leads to gundams or transformers or something silly, powered exoskeletons make a sort of sense for civilian/police use, but for military use up against real tanks they're a big "nope" to me. Mind you "technicals" make no sense to me either, so what do I know?

Real militaries tend to focus on two options. Sit back and fire missiles until everything is dead (US) or infiltrate soldiers in and have them act as terrorists/militias (Russia.) The age of tank tactics ended decades ago, the Russians failed using them in multiple wars and the US ditched them even further agi for light vehicles acting as scouts for airpower and artillery.

If you read reports and memoirs for recent wars like Iraq the US tanks would withdraw if they engaged machine guns due to the fragility of tanks and would instead call in airstrikes from a safe distance.

Any discussion of ground forces is going to be about limited warfare where carpet bombing and nukes are off the table, so presumably you are attempting to minimize civilian casualties and long distancr tank fire is off the table. Close support tanks don't work because hand held shaped charges knock them out easily, see first Chechen War.

Edit: Modern warfare is basically a game of whack a mole. The whackers win open engagements via air power, then try to keep the moles out of civilian populations they use as cover/dirt. The moles infiltrate civilian populations and try to spread through them. Since air power dominates open engagements tanks don't have a purpose there, and since hand held shape charges blow up million dollar tanks to the tune of 10k they don't have a role in the cities where the moles are. Tanks don't serve a purpose in modern warfare (always subject to change).

Power armor is not the same concept as gundams, which are tanks. It is a way to minimize casualties while ferreting out the moles, and so needs to remain on the small size.

[factotum]

Wasn't the Battle of 73 Easting during the 1991 Gulf War described as "the last great tank battle of the 20th century"? OK, that is still decades ago as you say, but certainly recent enough to be important. As for tanks running away from machine guns, got a citation on that?

[Tvtyrant]

Wasn't the Battle of 73 Easting during the 1991 Gulf War described as "the last great tank battle of the 20th century"? OK, that is still decades ago as you say, but certainly recent enough to be important. As for tanks running away from machine guns, got a citation on that?

It is in The Highway War: A Marine Company Commander in Iraq, I will find the page later today or tomorrow (I have to get out my copy). We talked about it a lot in class.

[Gnoman]

Backpack nukes are a very bad idea yes, but flamethrowers were in use in WW2, and very probably will be in any future war (unless a Geneva convention has banned them since then, which I don't remember hearing about, but then there's a lot I have heard about that I don't remember), they are not like civilian flame throwers which are for starting bonfires and destroying weeds, military flamethrowers throw a narrow stream of napalm quite a long way (fifty or sixty yards), they are not at all indiscriminate, though they are certainly nasty.

Flamethrowers are essentially extinct as a military weapon. The US removed them entirely from service in 1978, and the Soviets were the last major power to discontinue use in the 1980s. You are correct that they are still perfectly legal weapons of war (subject to a few special restrictions on incendiaries), but they're tactically useless. ~50 meters isn't bad, but anything you want to set on fire is going to outrange you considerably, and the fire rate of modern small arms means that trying to get that close borders on suicide.

The weapon system has been replaced with a variety of incendiary rockets. These are much longer ranged, just as accurate, and don't require a soldier to carry a massive "one hit and everyone around you dies horribly" fuel tank.

[Jackaccount]

Have you considered using things like elecrolasers or pulsed energy projectiles? There's more than one way for a laser to be lethal. Also regarding a post about how to shoot molten metal, I would use some sort or railgun/coilgun, existing versions already ignite the air when they're fired.

[Anymage]

To repeat what I said when you first started this thread: If Rule of Cool and having black ops cyborgs tangle with physics bending monsters is your thing, just go with that.

Other people have covered why lasers and similar particle beam weapons don't work well in reality. If you ignore that, the best thing about combining electrolasers with a more "normal" laser weapon is that you can switch between taser function and vaporizing a hole through your target. That's more akin to changing the setting on your phaser than anything else, though.

[Tyndmyr]

Good luck hitting a person with a bazooka, which is inherently slow and inaccurate.

You might hit around the guy, but then the question is how much explosive are you chucking at him for it to be lethal? The US could deploy backpack nukes and flamethrowers but chooses not to because massive civilian casualties are considered detrimental to the mission.

Flamethrowers are specialist tools, and are used in situations that call for them(tunnel fighting, for example). Civilian casualties are mostly not a factor there. Risk to operator, limited fuel supply and limited range are much more significant reasons why soldiers use guns instead.

Modern anti-tank weaponry is pretty accurate, and any man-portable armor isn't going to survive a round from one, so rate of fire is mostly unimportant.

[Tvtyrant]

Flamethrowers are specialist tools, and are used in situations that call for them(tunnel fighting, for example). Civilian casualties are mostly not a factor there. Risk to operator, limited fuel supply and limited range are much more significant reasons why soldiers use guns instead.

Modern anti-tank weaponry is pretty accurate, and any man-portable armor isn't going to survive a round from one, so rate of fire is mostly unimportant.

Pretty accurate for firing at massive targets that move in straight lines. The US military experimented with rocket guns (Gyrojets) the ammo of which was lighter and had better penetration then bullets. Unguided rockets are unfortunately inaccurate, with groupings of less then a foot which was still considered too much for killing soldiers. Gun groupings are extremely tight and take very tiny amounts of time to aim compared to rocket launchers.

Flamethrowers were discontinued due to abuses during Vietnam. The ability to destroy cover was why they were useful, and the range component would rule out grenades (which see tremendous use.) Due to the whack a mole character of modern warfare combat is nearly always at extremely short ranges in urban environments, or extremely long ranges where model assault rifles struggle.

[factotum]

Pretty accurate for firing at massive targets that move in straight lines. The US military experimented with rocket guns (Gyrojets) the ammo of which was lighter and had better penetration then bullets. Unguided rockets are unfortunately inaccurate, with groupings of less then a foot which was still considered too much for killing soldiers.

But you don't need to kill the soldier in the power armour to effectively remove them from the fight, you just have to damage the armour sufficiently to make it unusable, which requires far less accuracy than going for a kill shot--hit the suit in the arm and blow a hole through it, that still severely restricts what the guy inside can do (even assuming that he can keep going despite the blood loss).

Also, Gyrojets were inaccurate because of poor manufacture of the ammo--it required the rocket nozzles to be very precisely drilled in order for the round to spin evenly and fly straight, and the early ammo simply wasn't made to a high enough standard. Later they fixed that, but it was too little, too late.