Got a Real-World Weapon or Armor Question? Mk. VII

[Lapak]

@Lapak

It's not actually that simple. If person A was pushing against person B then yes. But once you let go of something momentum must be conserved. Think about a musket firing a lead bullet, and the bullet hitting a brick wall. When it hits the wall the bullet is flattened. If the same amount of force had been applied at the gun, the bullet would have been flattened inside the barrel. When the bullet is fired, it, the gun, and the person shooting, experience less force, but that force is applied over a longer amount of time, as the bullet is accelerated over the entire length of the musket barrel. When the bullet hits the wall, the wall and the bullet suffer a greater force but in a shorter amount of time . . . but now the gun and the shooter are totally out of the equation.

The total force is the same, and the entire force is applied to the shooter. It isn't about what the musket ball suffers and when; it's about what the target (the wall) and the source (the shooter) suffers - this is not caused by the ball itself, which simply transfers the energy from place to place, but by the explosion. Minus a small amount due to friction with the air, it's the same - and the lesser amount is suffered by the target.

[fusilier]

The total force is the same, and the entire force is applied to the shooter. It isn't about what the musket ball suffers and when; it's about what the target (the wall) and the source (the shooter) suffers - this is not caused by the ball itself, which simply transfers the energy from place to place, but by the explosion. Minus a small amount due to friction with the air, it's the same - and the lesser amount is suffered by the target.

Can you clarify what you mean by "total force"? As typically F = ma. The bullet is clearly undergoing less acceleration when it takes 3.5 feet to accelerate from zero velocity to some velocity, and clearly much greater acceleration when it goes from some velocity to zero velocity in about 0 feet.

The amount of work being done is the same (work = force * distance), but the forces are clearly different.

[Lapak]

Can you clarify what you mean by "total force"? As typically F = ma. The bullet is clearly undergoing less acceleration when it takes 3.5 feet to accelerate from zero velocity to some velocity, and clearly much greater acceleration when it goes from some velocity to zero velocity in about 0 feet.

The amount of work being done is the same (work = force * distance), but the forces are clearly different.

I was imprecise in my word choice. Force was a bad choice; work is clearly better; amount of (kinetic) energy is what I was aiming at. "Enough work to accelerate the projectile to the speed it travels at" is applied to both the shooter and the target, and that amount is either enough to move the mass of the target a noticeable difference or it isn't. But you're right that this is complicated by the difference in how that energy is applied. You're more accurate not only in word choice but in the physics of it, with regard to how you qualify the statement. And that's never a bad thing. I should have looked at what you were saying more carefully before responding.

[fusilier]

I was imprecise in my word choice. Force was a bad choice; work is clearly better; amount of (kinetic) energy is what I was aiming at. "Enough work to accelerate the projectile to the speed it travels at" is applied to both the shooter and the target, and that amount is either enough to move the mass of the target a noticeable difference or it isn't. But you're right that this is complicated by the difference in how that energy is applied. You're more accurate not only in word choice but in the physics of it, with regard to how you qualify the statement. And that's never a bad thing. I should have looked at what you were saying more carefully before responding.

Yeah, we had a similar discussion earlier on this board and I also thought about force in that manner, at first.

A little more clarification, *kinetic* energy doesn't have to be conserved. Energy has to, but energy can be converted into so many forms. Force is what's actually going to move something. Force is needed to overcome friction, air resistance, and in the case of an animal, whatever other resistances the creature can apply with it's own internal muscles.

[Lapak]

Yeah, we had a similar discussion earlier on this board and I also thought about force in that manner, at first.

A little more clarification, *kinetic* energy doesn't have to be conserved. Energy has to, but energy can be converted into so many forms. Force is what's actually going to move something. Force is needed to overcome friction, air resistance, and in the case of an animal, whatever other resistances the creature can apply with it's own internal muscles.

All of that is true, and I appreciate the clarification. But all of that said - I'm not sure any of it makes enough difference to the basic situation of 'more or less standard projectile weapon (bow, sling, spear, handgun) fired at ranges appropriate for human-scale combat' to change the answer to 'can I push someone backwards with the impact of the projectile without being propelled back myself?'

[fusilier]

All of that is true, and I appreciate the clarification. But all of that said - I'm not sure any of it makes enough difference to the basic situation of 'more or less standard projectile weapon (bow, sling, spear, handgun) fired at ranges appropriate for human-scale combat' to change the answer to 'can I push someone backwards with the impact of the projectile without being propelled back myself?'

Yes, but it depends upon what you mean by being knocked back. I know that sounds weird, but you don't have to hit someone with a enough force to move their entire mass backwards, in order to get them to move backwards. I believe that you only have to unbalance the person, to either get them to fall or stumble. This is where the nature of how the body works with all of its limbs and muscles really complicates things. In the simplest sense, you may be able to treat a standing person as a standing board -- at which point you only need to get it to start rotating, which doesn't require much force near the top (or head), and falling is basically assured, but even that is too simplistic.

But yeah, somebody isn't going to be lifted up into the air and thrown through the window of the saloon by a shotgun blast. ;-)

[Theodoric]

Yes, but it depends upon what you mean by being knocked back. I know that sounds weird, but you don't have to hit someone with a enough force to move their entire mass backwards, in order to get them to move backwards. I believe that you only have to unbalance the person, to either get them to fall or stumble. This is where the nature of how the body works with all of its limbs and muscles really complicates things. In the simplest sense, you may be able to treat a standing person as a standing board -- at which point you only need to get it to start rotating, which doesn't require much force near the top (or head), and falling is basically assured, but even that is too simplistic.

The way nerves and (by reflex) muscles sometimes respond to certain stimuli, moving in another direction than straight down isn't at all impossible or even unlikely. Indeed, it's possible (for neurological and psychological reasons) that someone does that without even getting hit. IIRC, it's also a part of the 'stopping power' thing.

[fusilier]

The way nerves and (by reflex) muscles sometimes respond to certain stimuli, moving in another direction than straight down isn't at all impossible or even unlikely. Indeed, it's possible (for neurological and psychological reasons) that someone does that without even getting hit. IIRC, it's also a part of the 'stopping power' thing.

Hmm. I would like to hear more about this. Walking is little more than controlled falling. :-) So being unbalanced would be the key to stumbling or falling. But I suppose it's possible to flinch in such a way in response to being hit that could create such an imbalance. Although I still maintain that without "flinching" (for lack of a better word), it still may be possible for a projectile like a large caliber bullet to unbalance someone.

[fusilier]

Responding to Fusilier's post in the previous thread, the reason why revolvers are mechanically more complex than semiautos (in general) is that a revolver needs a mechanism to advance the cylinder, but generally a semiauto feeds a round by virtue of the slide pushing a bullet up a ramp. Comparing a 1911 to a Smith and Wesson Model 10, the 1911 has 59 parts, 14 of which are either extraneous to the function of the weapon and not moving, whereas the model 10 has 81 parts, 11 of which are extraneous to the function of the weapon.

Now, newer semiautos, like the Glock, have fewer parts than the 1911, but newer revolvers have not made the same gains when it comes to reducing mechanical complexity.

This is an old post, but I stumbled across some relevant information today. I wasn't totally convinced that revolvers were mechanically more complexed, but didn't have any way of refuting your evidence. It was just a general impression gleaned from statements concerning the robustness of old service revolvers.

I just ran across this:
http://www.allworldwars.com/Colt%27s...45%201909.html

Which states that the Colt 1909 .45 caliber double action pistol has only 44 parts total. Why exactly the S&W would have nearly twice as many parts, I don't know. Sometimes military weapons would be a bit too simple. The German Reichsrevolver didn't even have an ejection mechanism. Anyway, I'm just trying to gather some more info on this subject, and present it as I find it.

[Yora]

Now here's a rather odd question: When you put two arrows on a bowstring, does it reduce the impact force of the arrows? And let's discount the decrease in pulling strength, because you're ussing an unusual grip on the bow and the string.
But when you pull the string, it stores (tension?) energy and when you let it go, the energy is released. With two arrows on the string, the same energy would have to move twice the mass. But at the same time, my intuition tells me that the arrows would not penetrate only half as deep.

What's exactly the physics involved here?

[Norsesmithy]

Now here's a rather odd question: When you put two arrows on a bowstring, does it reduce the impact force of the arrows? And let's discount the decrease in pulling strength, because you're ussing an unusual grip on the bow and the string.
But when you pull the string, it stores (tension?) energy and when you let it go, the energy is released. With two arrows on the string, the same energy would have to move twice the mass. But at the same time, my intuition tells me that the arrows would not penetrate only half as deep.

What's exactly the physics involved here?

It's my experience that they will most likely each hit with less than half the strength of a single arrow, due to the fact that they will never launch or fly as cleanly as a single arrow, BUT if you were to manage to fire two arrows perfectly, preventing all that excess loss of energy, I think you would find that the two arrows would have more energy than a single arrow.

This is because two arrows (or a single heavier arrow) will be accelerated more slowly than one, though with similar amounts of force applied. The slower acceleration will cause the heavier payload to be accelerated for longer, and that will increase the efficiency of the system, resulting in greater energy imparted.

Of course, when hunting, one often chooses the less energetic lighter arrow because the higher velocity will cause it to shoot flatter, and you don't need much energy to push 2-4 scalpels through a deer.

But heavier projectiles being more efficient than lighter ones for a given amount of force applied is pretty universal. If you look at reloading data for firearms, you alway get more energy out of a heavier bullet than a lighter one, for the same amount of powder used, though a lighter bullet might be able to have more powder used with it.

[Stephen_E]

I suggest when doing those debates about the effects of a missile weapon on a target you use the terms Kinetic Energy and Momentum.

Strictly speaking Kinetic Energy doesn't have to be conserved, but momentum does.
Arrow would generally have a higher momentum for the same energy when compared to a bullet.

This is because Momentum = Mass x Velocity
Kinetic Energy = Mass x Velocity squared

While knocking someone backwards to any real degree with Arrows or bullets obviously doesn't work bu physics, knocking them down does because Humans are an inherently unstable creature when upright. Thus to knock a person down you merely have to destabilise them quickly enough or by large enough degree that they can't restabilise before falling, or temporaily shutdown or hamper the auto-stabilsation system that keeps you standing.

There is plenty of evidence that been shot by a bullet, and to a lesser degree an arrow, can essentially cause the brain to hang/reboot during which time the autostabilisation systen ceases to function and they collapse. Remember the human brain is an organic computer. All those problems that occur with your PC also can occur with human brains.

Stephen E

[Shademan]

can you actually take someones head off with an axe or sword?
consider these conditions:

excecution. You have a target that is alive and scared but resigned to his fate, possibly with his head on a block of wood.
I have heard that excecutioners using big axes sometimes had to finish the job with a knife...

battle. you may or may not be mounted, your target may be moving in any direction.

scientific. your target is happily sacrificing himself for science in a labd full of all kinds machines you need.

[Spiryt]

It's my experience that they will most likely each hit with less than half the strength of a single arrow, due to the fact that they will never launch or fly as cleanly as a single arrow, BUT if you were to manage to fire two arrows perfectly, preventing all that excess loss of energy, I think you would find that the two arrows would have more energy than a single arrow.

This is because two arrows (or a single heavier arrow) will be accelerated more slowly than one, though with similar amounts of force applied. The slower acceleration will cause the heavier payload to be accelerated for longer, and that will increase the efficiency of the system, resulting in greater energy imparted.

This entirely depends on bows efficiency with different weighs on arrows, though, if you shot two relatively heavy arrows from a bow, they will in result be overweight for a bow, and result in rather pathetic shot.

If they are sufficiently light, bow could theoretically shot them as single heavier one, but as you noted it's not really possible, and in result give two light arrows velocities of single heavier one.

But at the same time, my intuition tells me that the arrows would not penetrate only half as deep.

They would in the very best case have a bit more than a half of kinetic energy and half of momentum, with being twice less massive.

"Penetration" would generally vary entirely on material being penetrated, arrows themselves and stuff, but generally they would penetrate half as deep at best in such circumstances.

It would of course never happen, even in perfect conditions, as "multishot" is generally a failure, everyone who tried can agree.

Arrows don't want to fly even 1/8 of distance single one would, so even very careful choice of weights, stiffness and other things would lead one so far.

can you actually take someones head off with an axe or sword?
consider these conditions:

Uh, yes as hell?

Of course, in less than perfect conditions (battle) it would rarely happen, as not only it's hard to hit defending target that well, but also no one would possibly care, as decapitation of opponent doesn't give anything at all compared to "just" slashing his neck arteries.

But from infamous Deadliest Warriur to many other 'test' it's rather visible that average human neck and spine can be chopped in half rather easily.

As far as 'failed' executions go, particularly with an axe, executioner had just to hit at single optimized angle, otherwise part of the neck would be still not severed, while blade would already be stuck into the wood. I think that anyone can imagine what I'm talking about, without going to graphic.

[Shademan]

they don't show deadliest warriur in my country so I would not know about that.
Recently saw a movie tho', where heads were chopped off all over the place and it got me wondering if you really could take it off that easily.
'course, stuff like that should be taken with a grain of salt...

[Spiryt]

they don't show deadliest warriur in my country so I would not know about that.
Recently saw a movie tho', where heads were chopped off all over the place and it got me wondering if you really could take it off that easily.
'course, stuff like that should be taken with a grain of salt...

Well, typing "the arma dear cleaving" in Youtube produces interesting video.

Typing ''Test cutting on a deer'' produces more 'realistic' target even though conditions, user and blade are somewhat lacking.

Typing 'Fiskars billhook and a Finnish chef in action' gives living target, and typical slaughter condition.

I posted it like that instead of links, in case if somebody might not like the links content, particularly last one.

[Shademan]

should it worry me that these vids make me hungry?

[Yora]

No, fresh meat is a natural food source for humans.

[Shademan]

this is true.

It always amazes me how sharp and powerful them old weapons really were...

[Psyx]

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What I forgot to find out is how those pieces are fit and secured together. Does anybody know?

Rivets. Metal rivets.

Also, for the planks which made up the sides of the ship, how did they get them to bend in order to take the proper shape?

Get them wet and hold them in place, basically. They'll be formed to fit, in the same way that a cooper makes barrels. The way the planks over-lap is referred to as clinker-built.

I'm just curious if you've ever seen a fictional weapon that seemed reasonable.

I'm struggling to think of anything. Mankind is inventive. Especially when it comes to killing. If it works and can kill people; it's probably been done. Which is why fictional weapons always appear so laughable.

Hmm. I would like to hear more about this.

Essentially; people sometimes fall over because they think that they should, rather than for any real reason. Bullets themselves don't have vast amounts of energy: They just have a small areas to distribute it over. In fact; heavier rounds are even less likely to be able to physically knock people over, as they over-penetrate, and do not transfer all energy to the target. Knock-down is shock and psychological in the most part. It's perfectly 'normal' as far as physics is concerned to take a round and not even stumble. With body armour, it's possible to take rounds, and -in the heat of the moment- not even notice!

What's exactly the physics involved here?

Each arrow has half the energy, I reckon. When the string is released, the energy in the bow accelerates the arrosw. If there are two arrows, then there is twice as much mass that requires acceleration, so they get half as much each. This doesn't mean that they will penetrate to exactly half the distance of a single shot any more than 12 bits of buckshot penetrate to 1/12th the distance of a slug, though. However, they will transfer only half as much energy. I think.

[Crow]

Rivets. Metal rivets.

Yeah, I saw the planks were held in place by nails. Where they needed two planks to meet, the wood was cut at an angle so they fit together in an overlapping manner, then three nails held the overlapping pieces together. Is this the same way for the prow? Or did they use some other method? Because it seems like those would need to be huge nails for that part.

Get them wet and hold them in place, basically. They'll be formed to fit, in the same way that a cooper makes barrels. The way the planks over-lap is referred to as clinker-built.

So now for a stupid question; Would you soak (saturate) the wood then remove it from the water and then force it to the ship? Or would it require submerging the spine and ribs of the ship as you work with it?

[Karoht]

RE: Cutting off a head or a limb.

Hank Reinhardt did all kinds of test cuts with his weapons. He also had pigs on his property. He did tests armored, not armored, though I don't know if the creatures were alive or not at the time. He did not videotape any of it (that I can find) but supposedly did document it somewhere, and a friend of mine went down to visit him and personally witnessed some of those cuts. Suffice to say that a sword can indeed cut through something with the same diameter as a neck, and can indeed cut through a spinal column or neck.

[Mike_G]

Many swords an axes can cut through a neck or limb, but hitting at the right angle in combat probably didn't happen all that often. And, as somebody said above, severing is overkill. Hit the limb or neck hard enough to cut into it any real depth, and you take your target out. Maybe cutting your opponent's lower leg below his hauberk might sever it. If his weight's on it, it won't move much. Bones aren't all that resistant to sharp steel, as any butcher will tell you.

Axes can split logs, which are a lot tougher than necks. But if you've ever chopped anything, you know that it's all about hitting at the right angle.

[Construct]

So now for a stupid question; Would you soak (saturate) the wood then remove it from the water and then force it to the ship? Or would it require submerging the spine and ribs of the ship as you work with it?

The former. When you steam-bend a plank of wood you first steam it - either by holding it in a steam box, immersing it in boiling water, or heating green or soaked wood. This breaks some of the bonds between the wood fibres, allowing them to slide past each other more easily and thus allowing the plank to bend further without breaking. Once the plank is sufficiently pliable it is removed from the steam/boiling-water/heat-source and held against a form - such as a mold or the existing boat-frame - whilst it cools and drys and those broken bonds between the wood fibres reform to keep it in the new shape.

[Crow]

The former. When you steam-bend a plank of wood you first steam it - either by holding it in a steam box, immersing it in boiling water, or heating green or soaked wood. This breaks some of the bonds between the wood fibres, allowing them to slide past each other more easily and thus allowing the plank to bend further without breaking. Once the plank is sufficiently pliable it is removed from the steam/boiling-water/heat-source and held against a form - such as a mold or the existing boat-frame - whilst it cools and drys and those broken bonds between the wood fibres reform to keep it in the new shape.

Interesting. So does anybody know which method the vikings used? Steam box, immersion, or green planks over a big fire?

[Norsesmithy]

I think that the prevailing theory is that they used a combination of steam box and heating soaked wood.

You don't really want to heat green wood for this purpose, because it won't be dimensionally stable later.

[Subotei]

Interesting. So does anybody know which method the vikings used? Steam box, immersion, or green planks over a big fire?

The vikings (and many other pre-industrial cultures) made planks made by splitting the wood along the grain with wedges, rather than sawing the wood into planks as we would do today. This creates planks that are very flexible by comparison with sawn planks - its likely you would be able to bend them round to the shape of the ship far far better than sawn planks, so maybe these techniques were not needed extensively.

[Lev]

Which is why fictional weapons always appear so laughable.[/QUOTE]

as far as physics is concerned to take a round and not even stumble. With body armour, it's possible to take rounds, and -in the heat of the moment- not even notice!

Which is precisely why adrenaline and chemicals like PCP give people the capability of enormous feats-- the selling point of the barbarian.

You may rip your fingernails off, but that door is coming off it's hinge.

[Norsesmithy]

The vikings (and many other pre-industrial cultures) made planks made by splitting the wood along the grain with wedges, rather than sawing the wood into planks as we would do today. This creates planks that are very flexible by comparison with sawn planks - its likely you would be able to bend them round to the shape of the ship far far better than sawn planks, so maybe these techniques were not needed extensively.

Not quite, they used hewn planks, which are more flexible than sawn, but don't perfectly follow the grain like a split plank would. And they did used the various forming techniques like heating soaked wood and steaming wood.

Of course, it's a good thing that they don't just split planks, because you'd maybe get 4 or 5 good split planks out of the average 400 year old oak, and sometimes not even that many, because of all the non-uniform thing that living trees do.

[Deadmeat.GW]

I suggest when doing those debates about the effects of a missile weapon on a target you use the terms Kinetic Energy and Momentum.

Strictly speaking Kinetic Energy doesn't have to be conserved, but momentum does.
Arrow would generally have a higher momentum for the same energy when compared to a bullet.

This is because Momentum = Mass x Velocity
Kinetic Energy = Mass x Velocity squared

While knocking someone backwards to any real degree with Arrows or bullets obviously doesn't work bu physics, knocking them down does because Humans are an inherently unstable creature when upright. Thus to knock a person down you merely have to destabilise them quickly enough or by large enough degree that they can't restabilise before falling, or temporaily shutdown or hamper the auto-stabilsation system that keeps you standing.

There is plenty of evidence that been shot by a bullet, and to a lesser degree an arrow, can essentially cause the brain to hang/reboot during which time the autostabilisation systen ceases to function and they collapse. Remember the human brain is an organic computer. All those problems that occur with your PC also can occur with human brains.

Stephen E

Knockdown is also far too often described by witnesses as knockback.
Especially if the target going down was moving at the time.

And if the target was in between steps the amount of force to knock someone of balance and therefore trip them is far smaller.
It is all timing.

If you watch some Aikido (or any martial art with redicrects) you will see the throws and takedown attacks seem to be almost effortless and the thrown/tripped person tends to fly an impressive distance.
If you can however look for video's where it goes wrong and the target did not time his break-fall by rolling properly with the move.

I am not sure there are any around atm but my Sensei once told us that those would be more educational so as to shows us what not to do and what to look out for.
I dislocated my shoulder by trying to change my breakfall distance by a good 4 inches upwards.
Because I did not get the right curve on my roll and my opponent had not seen there was someone in my path behind him he did not aid me which meant I went flying quite fast at a very straight angle.
The net result was that I clipped the ground with my right shoulder just above the connection to the collarbone and the upper arm bone.
It snagged, I dislocated the bones as I was imparting too much force for it to stop just because I hit the floor and then I 'bounced' 5 feet into a wall.

Funny detail, when the sensei asked me if I was ok when I got up I told him yes and then promptly fainted face first into the table next to me which I broke...

The other students saw me sail 6 feet through the air, hit the ground and then they decribed it as me bouncing up and fly another 5 feet before bouncing of the wall after making a full rotation which meant I hit the wall chest first (I was very, very lucky as in that I did not hit my head at any point and that I managed to bang my shoulder in the wall in such a way that I popped my shoulder back into the socket).