Got a Real World Weapons or Armour Question? Mk XII

[Raum]

Short and sweet-- how lethal is, say, a hundred grams of explosive at close quarters?

Depends on the explosive. There are big differences between black powder, gun cotton, TNT, C4, and other explosives.

My question is, how energetic would the payload have to be in grams of TNT-equivalent to turn the enemy's head into chunky salsa?

One gram of TNT equivalent is defined as one kilocalorie...the amount of energy needed to raise one gram of water one degree Celsius. An undirected explosion of 100g of TNT would probably injure but not kill. Blinding or scarring are likely.

Shaping the blast so it turns into a plasma jet that fries the head is also a possibility.

Shaping the blast requires either mass or velocity, not something a tiny drone is likely to have. You'd probably be better off using them as "guided bullets" - rockets that can follow a target but hit at speed. Though rocket based ammo has its own set of issues.

If your drone is larger enough to shape/direct the blast, it would be far more effective.

Edit: Death or serious injury is possible. I don't want to make light of it. It's simply going to be far more effective if it's directed or contained rather than going of next to the target. For reference, original M80 firecrackers are ~3-5g equivalents. New ones are limited to 50 mg.

[Brother Oni]

There was an interesting discussion on a physics forum about what kind of bullet would be more "damaging" -- their consensus was that older, bigger rounds would do more damage. Damage being derived from force, the older rounds had more momentum (even though newer ones had more energy).

I think bullet design would also have a significant effect since hollowpoints are far more damaging than ball rounds to unarmoured targets. Frangible rounds particularly, such as the glaser safety slugs, appear to make mulch out of soft targets at least according to the videos on youtube.

All other things being equal though, I agree that the larger slower round would be more likely to knock people over.

EDIT-- Civil War soldiers often reported that being shot by a musket ball felt like being "kicked by mule." Also, they were known to tear their uniforms off, looking for the wound -- they were in shock and couldn't actually tell where they had been hit.

When you have 19mm balls being fired at you, it's going to hurt.
I was reading an account of the Pennisular War where it was sometimes reported that the musket balls were amputating hands and other appendages if the ball hit a lucky (or unlucky, depending on your point of view) spot.

[Avilan the Grey]

When you have 19mm balls being fired at you, it's going to hurt.
I was reading an account of the Pennisular War where it was sometimes reported that the musket balls were amputating hands and other appendages if the ball hit a lucky (or unlucky, depending on your point of view) spot.

Reminds me of the old trusted tactic of "let the army stand still while artillery shoot back and forth at chest height, watch cannon balls plow man-wide ditches in the sea of men" thing that was done up to the Napoleon wars. Ridiculous tactics from todays perspective but it was just part of war, back then (late 16th to early 19th century warfare).

Layman observations below:

Anyway, the whole force / hand thing.

No, Newton's law does not mean "identical" reaction, to begin with, it means "equivalent" reaction. So if you, somehow, is powerful enough to punch someone through a brick wall, not only are you already in a forward momentum that the counter force has to stop, but you are also braced for impact automatically, at least partially.

Regarding fists:

Fists as weapons might have been handy for fights, but they were a secondary use in that case; I have not heard of this particular theory before. As far as weapons go the fact that we can grab tools, not to mention the act of throwing with an ability to aim (something very very few animals can do, and almost all of them are also apes; most animals can't throw at all, much less with aim) are making better use of our hands and arms than beating someone with our fists if we really want to hurt someone. That said, we without a doubt automatically clench our fists when we get angry so there is definitely an instinct there.

As for punching through someone... If we are not talking about supers, it seems to me that the old "space ball of trash is best repulsed with a new new york ball of trash" thing is very fitting. Yes, humans can crack stone or boards with our fists, but hitting meat and bones with meat and bones will possible crack the bones, but it will not punch a fist-shaped hole right through someone.

I think bullet design would also have a significant effect since hollowpoints are far more damaging than ball rounds to unarmoured targets. Frangible rounds particularly, such as the glaser safety slugs, appear to make mulch out of soft targets at least according to the videos on youtube.

Sidenote: Swedish police often uses shredder rounds (hollow point) because they will not go all the way through a target and hit someone innocent behind.

[Mr Beer]

As for punching through someone... If we are not talking about supers, it seems to me that the old "space ball of trash is best repulsed with a new new york ball of trash" thing is very fitting. Yes, humans can crack stone or boards with our fists, but hitting meat and bones with meat and bones will possible crack the bones, but it will not punch a fist-shaped hole right through someone.

The scenario that I surmised would result in a penetrative punch was one in which the puncher was knocking his opponent through a brick wall...cartoon representations of Mr T aside, this is safely in the superhuman realm.

[Rhynn]

Question: How much of the skills needed to shoot accurately are shared between different weapons? How different are special situations like sniping from regular use?

I'm working out a cyberpunk ruleset based on Fuzion (Artesia: Adventures in the Known World, Sengoku, Bubblegum Crisis) and Cyberpunk 2020's Interlock, and I'm planning to use specialties for skills. Marksmanship (skill for using small arms) is probably going to be the most popular skill, judging by my CP2020 experience, so it's getting special consideration; and my weapon categories will obviously have to match it to a degree. Basically, specialties directly increase your skill (you use the total of skill+specialty) for that specialty use only.

So I'm trying to figure out what sort of specialties should exist, realistically (or at an acceptable degree of abstraciton), for Marksmanship. I've started off simply with CP2020's Handgun, Rifle, SMG. (Twilight 2013, my go-to example of great and realistic combat, just has the skills Longarm, Sidearm, and Support Weapons for personal weapons.) Should I include Shotgun, or Sniping, or even get more specific like Target-Shooting, Tactical Shooting, CQC? Should Rifle apply to assault rifles the same as hunting or sniper rifles? Should LMGs be under Heavy Weapons or Marksmanship, and should they have their own specialty? Should MMGs be separate from LMGs? And so on.

My army buddies were generally of the opinion that the Marksmanship + specialty thing makes sense, but only one of them even has training with handguns, and none of them are gun bunnies or experts with firearms.

[Avilan the Grey]

Question: How much of the skills needed to shoot accurately are shared between different weapons? How different are special situations like sniping from regular use?

This is one of those things that can be debated forever, especially if we are trying to make sense of it in a gaming ruleset perspective.

IRL, as a layman, I must say I think it has to do with the type of weapon. A short sword and a broadsword is closer to eachother than a hunting rifle and a handgun, I would assume; same basic grip, one-handed, same basic attack patterns. One is heavier and longer, but you should have a base skill with it.

I don't know enough to do a real life analysis, really, but if I was to do a game rule analysis:

First of all we need to divide up groups. This is arbitary to a huge degree and can (and has, in different rule systems) be divided in as small or large groups as you can possible want: Everything from "All one-handed weapons" to "individual swords".

Let's propose something like this:

Firearms:

Primary group: When you specialize in a weapon in a primary group, you automatically get 50% of your skill in any other weapon of that group but gains skill quicker than with unrelated weapons.

Secondary group: If you use a weapon "one group over" you automatically get 33% of your skill in weapons from that group.

Other firearms: If you use a weapon this far from your specialized skill you get 10% of your skill by default.

For example:
Primary Group - Rifles - 100% of your skill. You specialize in sniper rifles. You then grab another kind of rifle - 50% of your skill but can fairly quickly be trained up to 100% of your specialized skill.
Seconday Group - Automatic Rifles - 33% of your skill. No bonus in gaining new skillpoints.
Other Firearms: You, without training, start using a revolver. Automatic 10% of your original skill, no bonus in gaing skillpoints.

[AgentPaper]

No, Newton's law does not mean "identical" reaction, to begin with, it means "equivalent" reaction. So if you, somehow, is powerful enough to punch someone through a brick wall, not only are you already in a forward momentum that the counter force has to stop, but you are also braced for impact automatically, at least partially.

For a "normal" punch, certainly. But if you're punching someone that hard, then you're getting the force from somewhere, and unless you also have super-sticky feet (which seems like an odd power, unless you're spiderman), then that force needs to come from your own mass. You'd go less of a distance compared to your opponent relative to how much friction you're able to get between you and the ground, minus the friction your opponent manages to get between them and the ground. If you're bolted to the floor and they're standing on ice, then sure, they'll go flying and you won't budge.

At the very least, if you punch them hard enough to go through a wall, and keep your footing, then the ground beneath you is going to take the whole of that punch's counter force, and if you're swinging hard enough to send people through brick walls, then you're probably also producing enough force to mess up the ground pretty bad...if you're not standing on concrete, you'll probably just demolish it and go flying backwards anyways.

TL;DR: Super-human strength brings up a whole slew of problems, more the higher it gets. There's so much more involved than simply increasing muscle and bone strength that it's not really worth bothering with trying to make it realistic. Just have it work according to rule of plot, rule of cool, and rule of funny, and you (and anyone else in the room) will be much happier.

[Spiryt]

I'm confident a fist would penetrate a human if it imparted sufficient momentum to drive that person through a brick wall. There's a huge difference between forcibly knocking someone back and accelerating them to the point where they smash through rigid architecture.

If there was enough energy behind it, without some fundamental changes to human physique, this energy would probably destroy hand/wrist pretty badly, before any penetration would occur.

I've read some interesting research that suggests that early hominids got a bit of an advantage in the hand arrangement department (ie. our thumbs) when it came to fighting other hominids. It basically gave our evolutionary ancestors a built in weapon to fight each other with, and those that could form tighter fists had better natural weapons.

I seriously doubt hominids punched each other, though...

Even without weapons.

[Avilan the Grey]

For a "normal" punch, certainly. But if you're punching someone that hard, then you're getting the force from somewhere, and unless you also have super-sticky feet (which seems like an odd power, unless you're spiderman), then that force needs to come from your own mass. You'd go less of a distance compared to your opponent relative to how much friction you're able to get between you and the ground, minus the friction your opponent manages to get between them and the ground. If you're bolted to the floor and they're standing on ice, then sure, they'll go flying and you won't budge.

At the very least, if you punch them hard enough to go through a wall, and keep your footing, then the ground beneath you is going to take the whole of that punch's counter force, and if you're swinging hard enough to send people through brick walls, then you're probably also producing enough force to mess up the ground pretty bad...if you're not standing on concrete, you'll probably just demolish it and go flying backwards anyways.

TL;DR: Super-human strength brings up a whole slew of problems, more the higher it gets. There's so much more involved than simply increasing muscle and bone strength that it's not really worth bothering with trying to make it realistic. Just have it work according to rule of plot, rule of cool, and rule of funny, and you (and anyone else in the room) will be much happier.

The way you usually position yourself when throwing a heavy punch, you lean foward quite a bit as you "punch through", following your fist forward.
This usually means that yes the force will be transfered to the floor; your legs are in an angle and will direct the foce downwards. But first the force has to go through your fist, your arm, your shoulder, your waist... all that contains joints and ligaments that will absorb part of the force. Basically if you punch someone through a wall you will most likely end up with a broken bone or more in your fist, a a sore shoulder, tense muscles in your back and no, not any cracked floorboards.

Now if you add superhumans... Yes, if a super strong person does it there might be cracks in the floor when he walks away. Of course superhuman physics only apply when the writers want to, as we all know.

If there was enough energy behind it, without some fundamental changes to human physique, this energy would probably destroy hand/wrist pretty badly, before any penetration would occur.
---
I seriously doubt hominids punched each other, though...

Even without weapons.

Exactly my point.

As for your second point. We don't know. All we know for certain is that humans instictively clench our fists when we are aggressive. And that chimpanzees use weapons to beat eachother with as well as bite and tear. They can however not form proper fists with their hands, their palms are too long and their thumbs are too short.

[GnomeFighter]

Question: How much of the skills needed to shoot accurately are shared between different weapons? How different are special situations like sniping from regular use?

Situation is more important than type. I know I can pick up most guns and bows and set them up and shot at a target with some degree of accuracy with little more than a few moments familiarisation with the sighting system and a few shots to get my eye in to the characteristics of that weapon. Once you have the basic understanding of how to fire a weapon, relaxing, breath slowly, don't force it, those skills are very transferable. Guns are easy to get somewhere near the target if you have some basic training. Bows, less so due to the phyical input, but once you have the muscles and skills you can transfer those.

It is the last few % that comes in to play with further training and setting up etc.

As for "special situations" I would not call sniping "special" in shooting terms. Many hunters and sports shooters have skills on par with snipers. Snipers do have other skills, and often combine the acuracy of good target shooters with the outdoors skills of a good hunter and throw in allot of the skills of a good soldier too. A good target shooter should be able to match the acuracy of a military sniper but would not be able to identify a good place to set up.

In terms of acuracy on combat situations (both forces and police) the skills are transferable, it is still a case of point the open end at the target. The diffrence comes with being able to USE those skills under pressure. Target shooters, hunters and, for that matter, snipers have a very diffrent set of stressors than someone in a fire fight. This however is not related to the weapon you are using. If you panic with a pistol you will panic with a shotgun and use both of them just as badly.

[Rhynn]

As for "special situations" I would not call sniping "special" in shooting terms. Many hunters and sports shooters have skills on par with snipers. Snipers do have other skills, and often combine the acuracy of good target shooters with the outdoors skills of a good hunter and throw in allot of the skills of a good soldier too. A good target shooter should be able to match the acuracy of a military sniper but would not be able to identify a good place to set up.

You think? Sniping seemed like the exception situation to me. (When I say "sniping," I don't mean just using a scope, I mean making a shot at ranges like 1,000-2,000 yards or more.) I don't think most shooters are going to be consciously and scientifically adjusting for wind direction and strength, etc., are they?

I've never fired a real gun, though, much less been trained in it.

[Hjolnai]

I've been wondering: How much would full plate armour protect against the kinds of magical attacks we see in fantasy (particularly RPG systems)?
Other armour systems may also be interesting to consider.

My thoughts:
Fire: Should be good protection - the conductive steel spreads the heat out over a wider area, while the padding beneath spreads it over time. Also, a layer of sweat should be helpful. Just hope that the fire doesn't reach your face or your eyes and lungs will be in trouble. Also, watch out for the cloth padding catching fire, though there won't be much air for it.
Heat exhaustion may be an issue.

Frost: Similar to fire, but reduces the problems of overheating rather than increasing them.

Lightning: You're wearing a Faraday cage, so it should be much less dangerous than normal. Incomplete sets of armour (eg without greaves) may prevent grounding, which makes it more dangerous.

Acid: Most of it will get stuck on the plates. Should stop personal damage, but the steel will be compromised. Again, hope to avoid face hits, because of the breathing holes and eye slot.

[Mr Beer]

If there was enough energy behind it, without some fundamental changes to human physique, this energy would probably destroy hand/wrist pretty badly, before any penetration would occur.

Yes, of course. Superhuman acts of strength require ancillary superpowers.

"Simply" hoisting a car over your head needs skeletal and connective tissue reinforcement as an obvious starting point and then you have things like whether you can maintain your stance with a couple of tons of metal whooshing around in your arms.

Punching with enough momentum to penetrate say 10 inches of human without first reinforcing the striking arm would end up as a horrible mess for everyone involved.

[Spiryt]

Lightning: You're wearing a Faraday cage, so it should be much less dangerous than normal. Incomplete sets of armour (eg without greaves) may prevent grounding, which makes it more dangerous.

I'm rather clueless as far as electricity goes, but even most 'hermetic' suits of plates probably would have problems with being grounded, or forming very complete cage...

Some most elaborate armors could probably have tight plates/mail down to the soles of feet, but from obvious reasons those would be pretty universally mounted only, so rider wouldn't be grounded from obvious reasons.

[Dead_Jester]

I'm rather clueless as far as electricity goes, but even most 'hermetic' suits of plates probably would have problems with being grounded, or forming very complete cage...

Some most elaborate armors could probably have tight plates/mail down to the soles of feet, but from obvious reasons those would be pretty universally mounted only, so rider wouldn't be grounded from obvious reasons.

Although one has to assume that in a scenario where your average knight in plate armor considers electricity a serious threat to his continued existence that some form of grounding device (such as strips of chain running from the base of the armor to the ground) would be kept handy even if it is not a permanent part of the armor.

[AgentPaper]

Some most elaborate armors could probably have tight plates/mail down to the soles of feet, but from obvious reasons those would be pretty universally mounted only, so rider wouldn't be grounded from obvious reasons.

It doesn't actually matter whether there's a direct connection to the ground. The only thing that matters is that the shortest, easiest path for the electricity to move on doesn't include any of the wearer's body parts. If you're in full plate riding a horse, the shortest path means going through your armor, into your horse, and then into the ground. So, you'll be fine, assuming you survive the fall after your horse dies. (Unless it's similarly armored, or you have one of those grounding chains, in which case you're both fine)

[Brother Oni]

My thoughts:
Fire: Should be good protection - the conductive steel spreads the heat out over a wider area, while the padding beneath spreads it over time. Also, a layer of sweat should be helpful. Just hope that the fire doesn't reach your face or your eyes and lungs will be in trouble. Also, watch out for the cloth padding catching fire, though there won't be much air for it.
Heat exhaustion may be an issue.

Very much depends on the fire attack. A sufficiently hot and condensed bolt of fire would just melt through the steel (and by extension the wearer). Likewise, a lower but more extended exposure to fire would just set the person on fire like a flamethrower.

As for the padding igniting, some of it is still exposed to the atmosphere, where there's plenty of air for it to burn in.

Frost: Similar to fire, but reduces the problems of overheating rather than increasing them.

Similar issues as to the fire attack - extreme condensed cold would supercool the steel, making it incredibly brittle, while longer lower intensity exposure would cause frost burns to skin in contact to metal, not to mention the possibly of hypothermia.

Lightning: You're wearing a Faraday cage, so it should be much less dangerous than normal. Incomplete sets of armour (eg without greaves) may prevent grounding, which makes it more dangerous.

On top of the other suggestions, you'd have to assume that your skin isn't in contact with the metal or the padding isn't sufficiently damp enough with your sweat to conduct.
That said, you don't need much current to pass through your upper torso to sufficiently disrupt your heartbeat.

Acid: Most of it will get stuck on the plates. Should stop personal damage, but the steel will be compromised. Again, hope to avoid face hits, because of the breathing holes and eye slot.

Ah, something I'm on a bit firmer ground with.

Depends on the acid although any acid worthy of the name will have a major affect if it hits the face and gets into the soft tissues. Regardless of type, a long duration spray would probably incapacitate the target at the very least, if not kill.

Concentrating on small 'bursts' of acid, lets take something nice and simple like concentrated hydrochloric acid.
Against steel plate, it won't do a thing - iron (let alone treated steel) simply isn't reactive enough for short term exposure to HCl to do anything; it's more likely to drip off before it starts corroding the plate.
Even soaking into aketon/gambeson isn't going to degrade the padding quickly and it'll take a few minutes for it to start burning skin.
The acid fumes however will have a similar effect to tear gas on the wearer though and will probably be very debilitating.

Something significantly nastier like hydrofluoric acid... there's not going to much left of the target (or the thrower if they're not careful).

Suppose we had a theoretical acid like the xenomorph's blood from the Alien franchise; it's going to eat through the armour quickly, with the fumes being significantly disabling.
However when Cpl Hicks was hit with the acid, his armour was designed to breakaway quickly, thus it limited the damage the blood did.
There won't be such an option with plate, which requires somebody else to help armour the wearer (normally a squire's job for a knight), so the acid will inflict more injury or even kill the target unless someone's there to get the affected pieces off.

Edit: Sorry, forgot to say that if you offered a bit more detail regarding the cold/fire attacks (a particular RPG system for example) then we can start giving more useful suggestions.

[Beleriphon]

Very much depends on the fire attack. A sufficiently hot and condensed bolt of fire would just melt through the steel (and by extension the wearer). Likewise, a lower but more extended exposure to fire would just set the person on fire like a flamethrower.

As for the padding igniting, some of it is still exposed to the atmosphere, where there's plenty of air for it to burn in.

I'd imagine that most fire bolts from fantasy games have more in common with HEAT rockets rather than a stove's burner.

[Raum]

Question: How much of the skills needed to shoot accurately are shared between different weapons? How different are special situations like sniping from regular use?

Speaking purely about firearms, a lot of things are common no matter the weapon. Sight picture, breath control, trigger pull, relaxed tension, etc. Even the basic stances and methods of holding a weapon are the same within a given type (pistol vs rifle) and similar across the two. An experience shooter can easily pick up a weapon he's never used before and be at 90% of his skill level with half an hour's practice. That last ten percent will often take longer - it's about extremely fine differences in shooting mechanics.

One item that differs significantly is distance shooting vs short range. A sniper is going to have to learn to read wind changes and adjust for significant drop. There's a big difference between shooting a rifle at 200 meters vs a kilometer plus. Even minor things like humidity start to be a factor.

[TuggyNE]

I'd imagine that most fire bolts from fantasy games have more in common with HEAT rockets rather than a stove's burner.

Really? HEAT works by forcing a very high-speed jet of solid metal through other solid metal by means of sheer kinetic momentum; any heat formed is purely incidental and irrelevant to the penetration (though it's certainly handy once you get through).

In 3.5 terms, HEAT is piercing damage that ignores hardness up to a certain amount, with auxiliary sonic, fire, and maybe slashing components.

[Beleriphon]

Really? HEAT works by forcing a very high-speed jet of solid metal through other solid metal by means of sheer kinetic momentum; any heat formed is purely incidental and irrelevant to the penetration (though it's certainly handy once you get through).

In 3.5 terms, HEAT is piercing damage that ignores hardness up to a certain amount, with auxiliary sonic, fire, and maybe slashing components.

I'm aware of how a HEAT round works, thus the comparison. In 3.5 I'm sure you could classify a HEAT round like that, but a relatively realistic take on fantasy could certainly treat bolts of fire (seriously its a blast of fire that hurtles through the air and impacts a target). That sounds like the way a HEAT round works, at least at a basic level.

[Rhynn]

Speaking purely about firearms, a lot of things are common no matter the weapon. Sight picture, breath control, trigger pull, relaxed tension, etc. Even the basic stances and methods of holding a weapon are the same within a given type (pistol vs rifle) and similar across the two. An experience shooter can easily pick up a weapon he's never used before and be at 90% of his skill level with half an hour's practice. That last ten percent will often take longer - it's about extremely fine differences in shooting mechanics.

One item that differs significantly is distance shooting vs short range. A sniper is going to have to learn to read wind changes and adjust for significant drop. There's a big difference between shooting a rifle at 200 meters vs a kilometer plus. Even minor things like humidity start to be a factor.

Thank you!

This pretty much lines up with what I was thinking.

[warty goblin]

I'm aware of how a HEAT round works, thus the comparison. In 3.5 I'm sure you could classify a HEAT round like that, but a relatively realistic take on fantasy could certainly treat bolts of fire (seriously its a blast of fire that hurtles through the air and impacts a target). That sounds like the way a HEAT round works, at least at a basic level.

I find this a very odd argument. I mean when somebody says 'blast of fire that hurtles through the air' my first thought is not that this is going to behave anything like a jet of liquid copper traveling ten plus times the speed of sound. My mind tends towards it being, well, fire. Dragon breath, burning pitch sort of deal; very hot and liable to ignite stuff but not something that carves through plate steel like a knife through butter.


...and having been burned by various bits of open flame and hot metal in my food service career, fire is scary and painful enough. Nothing like getting halfway to the counter before realizing that the rag you're using to hold onto the pot of boiling water is on fire.

[TuggyNE]

I'm aware of how a HEAT round works, thus the comparison. In 3.5 I'm sure you could classify a HEAT round like that, but a relatively realistic take on fantasy could certainly treat bolts of fire (seriously its a blast of fire that hurtles through the air and impacts a target). That sounds like the way a HEAT round works, at least at a basic level.

OK, I wasn't sure, because it sounded very unintuitive (still does), and because I used to have a misconception about how they worked that sounded similar. The velocities/pressures you need for that to be relevant are extremely high, and it's not actually fire at all, it's more like a super-fast bullet.

Normally, I figure "fire" damage is more like wood combustion at the low end, and thermite at the higher end. (Maybe some side effects of nuclear blasts, if you want to get fancy.) Calling it "fire" damage when you actually mean "hyper velocity penetrator" is just weird. (This is especially true because you don't actually need explosives as such to get a similar effect, just very high speeds.)

[Brother Oni]

I'd imagine that most fire bolts from fantasy games have more in common with HEAT rockets rather than a stove's burner.

I was thinking more like a plasma weapon (Babylon 5, Terminator franchise, W40K, etc) on the upper end of the power spectrum, but any sort of pulsed directed energy weapon would probably be equivalent.

My mind tends towards it being, well, fire. Dragon breath, burning pitch sort of deal; very hot and liable to ignite stuff but not something that carves through plate steel like a knife through butter.

Dragon breath would be closer to a civilian flamethrower in my opinion (sustained burning stream of gas), while pitch 'cheats' by smearing a burning subtance over the target, much like napalm.

In the absence of any clarification, let's start some open speculation:

In my opinion, a fire bolt spelt calls up an amount of burning gas which is then directed at the enemy. Depending on the temperature of the burning gas (presumably the more powerful the spell, the hotter), it can melt through plate steel (~1370C).

Let's start with how much burning gas we need to hurt somebody:

Civilian flamethrowers use propane or methane (natural gas), which have a flame temperature in air of 1980C and 1950C respectively, so that would probably be a good starting point for a basic spell.

Since you can pass your hand through an open flame briefly with no damage, I'd think the duration and contact area would also be important. This would probably give an idea of the minimum volume of a basic bolt.

Working on this and trying to keeping it simple, let's make the area of contact the chest/breastplate, or ~0.07m².

Level of injury is the next step - assuming immediate incapacitation, we'd have to heat the bare skin to 72C and according to this site (link), achieve a heat transfer rate of greater than 3kW/m², which would give our duration of contact, target end point and a base point of volume (gas containing 0.21kW of thermal energy).

Next we need to find the thermal conductivity value of human tissue... here it is.

Dammit, I've run out of time at the moment to crunch this. I'll carry on later unless someone wants to take over.

[Rhynn]

I find this a very odd argument. I mean when somebody says 'blast of fire that hurtles through the air' my first thought is not that this is going to behave anything like a jet of liquid copper traveling ten plus times the speed of sound. My mind tends towards it being, well, fire. Dragon breath, burning pitch sort of deal; very hot and liable to ignite stuff but not something that carves through plate steel like a knife through butter.

Same. My first thought is a short blast from a flame thrower (like so). Especially when it's pretty rare for a bolt of fire in a RPG to actually go through someone.

HEAT warheads are based on pressure, not heat. It's just an acronym. (Sure, they get very hot, but not usefully so.) I don't see how bolts of fire would have anything to do with them.

I'm aware of how a HEAT round works, thus the comparison. In 3.5 I'm sure you could classify a HEAT round like that, but a relatively realistic take on fantasy could certainly treat bolts of fire (seriously its a blast of fire that hurtles through the air and impacts a target). That sounds like the way a HEAT round works, at least at a basic level.

"Blast of fire hurtling through the air."
"Shaped charge explosive propels superplastic metal forward on impact."

I don't think those sound very much alike, myself. The first sounds like a flamethrower (granted, that's a blast of burning liquid/gas; though bolts of fire could certainly be the same), the second is a HEAT warhead.

A HEAT warhead's basic principle is shaping an explosion on impact to propel material through a target using pressure. (They do not melt through armor, not being nearly hot enough to melt metal*.)

* Edit: Okay, they're nearly hot enough to melt aluminium, and hot enough to melt bismuth and some aluminium alloys, but not, say, silver, gold, iron, or copper (what the penetrator is actually made of). I don't know what the melting point of chobham is, but given it's ceramic encased in metal, it's probably pretty high. The copper penetrator isn't melted, it's pressurized and deformed far beyond it's breaking point.

[GnomeFighter]

You think? Sniping seemed like the exception situation to me. (When I say "sniping," I don't mean just using a scope, I mean making a shot at ranges like 1,000-2,000 yards or more.) I don't think most shooters are going to be consciously and scientifically adjusting for wind direction and strength, etc., are they?

I've never fired a real gun, though, much less been trained in it.

Fullbore target shooting goes up to a range of 1000 yards for competition, using 'iron' aperture sights (No scopes) for "target rifle" class, or 1200 with scopes for "match rifle" class. They are most definitely adjusting for wind and environmental conditions.

In the case of deer stalking they are sometimes shooting at over 500 yards, although 200 yards is more normal, and they do not have the luxury of setting up in the same way a sniper or target shooter dose.

Snipers are not normaly shooting at the range of Fullbore target shooters. The maximum effective range of the 7.62×51mm (Nato Standard Cartridge) is only about 900 yards. Fullbore shooting uses this, but is only having to punch through paper. For the .338 Lapua Magnum, the max effective range is 1400 yards, about the same as target shooters. These are the two "normal" cartridges used by millitery snipers. Even the 14.5×114mm anti material cartrage only has a max range of about 2300 yards, and this would normaly be shooting at vehicles rather than people. Snipers will normaly be shooting under the effective range, however they do not always have the luxury of having an idea of what the ranges should be before shooting, but have a larger area to hit. Swings and roundabouts.

Millitery snipers are generally good, as you would expect from someone whos job it is to shoot, but not superhuman. The accuracy of a top rifle shooter will much higer than an average military sniper. They have a whole gamet of other skills that let them do there job, just like anyone. That is not to say that top snipers are not up there with top target shooters, just that in genaral target shooters will be on par with snipers.

For more useless infomation take a look at this:
http://en.wikipedia.org/wiki/Longest...d_sniper_kills

As you see there are very few confirmed kills by snipers over 1500 yards.

A strange myth, like the ninja myth, seems to have grown up round snipers, that they are some sort of superhuman with the ability to shoot the pips out of an apple at 3 miles. They are only human and many probably practace less than alot of target shooters.

[Brother Oni]

Okay, let’s make our target medium rare and assume a penetration of 0.5cm. The average density of the human body is 1.062g/cm3, so we have about (706.9*0.5)/1.062 = 332.8g of flesh to cook.

The average specific heat capacity of the human body is 3470 J/kg/C and using an external body temp of 37C (he’s been exercising) and in order to char our target nicely I reckon we need (3470J*35C*0.3328) = 40.4kJ.

Assuming our firebolt works by convection, the forced heat transfer coefficient of natural gas is about 10 W/mK, so a one second contact of propane that would encompass the whole chest would transfer (1943K*0.07m2*10 W/m2K) = 1360J, nowhere near enough to cook our target.

In order to deliver the required amount of energy in that time, our firebolt would need to have a temperature differential of 57,714K, which is a mite bit toasty.


Now for the plate armour:

Assume an identical area of iron breastplate and let’s make it fairly thick at 2mm for a total volume of 141.4cm3 and hence 1113.2g of metal (it’s close enough to steel, density wise).

The heat capacity of iron is about 0.45 J/g/K, so applying 40.4kJ to the breastplate would increase the temperature by ~81C, more than enough to cause painful burns to unprotected skin, plus repeated spells would literally cook the target as the heat wouldn’t have time to dissipate.
The plate would protect the wearer for a couple of hits though.

Note that this is all fairly back of envelope stuff and makes quite a few assumptions (the target not catching fire, uniform distribution of heat, etc), not to mention the inevitable mistakes somewhere.

Edit: formatting.

[Hjolnai]

Okay, let’s make our target medium rare and assume a penetration of 0.5cm. The average density of the human body is 1.062g/cm3, so we have about (706.9*0.5)/1.062 = 332.8g of flesh to cook.

(...Quote cut for length)

Interesting. That's quite a temperature raise in the metal compared to what it does to flesh (unsurprisingly), but the thick padding beneath combined with heat capacity of sweat is probably going to help. Also, the padding won't conduct heat anywhere near as quickly as the metal - so it will spread over a much wider area before it sinks through the cloth.

Taking this much superheated gas to the front is probably going to mean some gets through the helmet though. Any significant amount of the gas in the eyes is going to be really bad news. Still better than the victim would have fared without armour though.


I should have been more specific in my question. Certainly it's interesting to think about different systems of magic and of armour, but answering the question with detail is always easier when the question itself is detailed.

I was thinking mostly about D&D, and I guess most computer game systems, where various sources of magical damage cause serious injury but are not guaranteed to be lethal. In those situations I would expect good armour to provide serious protection against many such threats. In systems where magic tends to be overkill (or would be if not for superhuman toughness, which I guess applies for high-level D&D too), armour can't be expected to do as much. An analogy for the difference is in gunpowder weapons - armour might stop a contemporary bullet, but it won't save you from a cannonball.

I was also thinking about Gothic-style plate (for complete specificity), but other types of armour could be equally interesting to investigate.

[Brother Oni]

Interesting. That's quite a temperature raise in the metal compared to what it does to flesh (unsurprisingly), but the thick padding beneath combined with heat capacity of sweat is probably going to help. Also, the padding won't conduct heat anywhere near as quickly as the metal - so it will spread over a much wider area before it sinks through the cloth.

You're still talking about 100+ C metal only a couple of clothing layers from the skin. The padding isn't going to help that much.

The temperature rise isn't that much though - 35C (to get from 37 to 72) compared to 81 (25C to 106C).

What would be interesting would be to vary the contact area (currently 40.4kJ of propane would occupy ~3.6L so it's a fairly hefty ball of fire) as that would lower the energy requirement for harm and hence the plate may afford more protection (thermal conductivity of the armour would play a more important part).

I was thinking mostly about D&D, and I guess most computer game systems, where various sources of magical damage cause serious injury but are not guaranteed to be lethal. In those situations I would expect good armour to provide serious protection against many such threats. In systems where magic tends to be overkill (or would be if not for superhuman toughness, which I guess applies for high-level D&D too), armour can't be expected to do as much.

While damage to human tissue with cold isn't going to have too different an energy requirement to heat (going from 37C to 0C in comparison to up to 72C), the amount of protection afford by steel is going to be significantly less: while iron melts at 1538C, it goes brittle at only about -29C.

Comparison to D&D is going to be tricky - I believe spending a round (10 seconds) in a medium campfire only inflicts 1d6 damage or 2d6 if it's been burning for a couple hours.

1kg of moderately dry wood generates 4kW for an hour and I'd say a decent sized camp fire is about 5kg of wood.
This would give an energy output of 20kW or 200kJ to the idiot standing in the fire, which equates to 2d6 damage.

I was also thinking about Gothic-style plate (for complete specificity), but other types of armour could be equally interesting to investigate.

I assumed 2mm armour earlier, which is fairly comparable to gothic plate. Other armour materials can be worked out by looking at their respective specific heat capacity - for a solid piece of armour, just assume it's uniform (if you ask me to do mail, I will hurt you).