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

[Psyx]

If the target was moving (forward) it makes the physics even more unlikely.


Knockback due to physical force was kind of dispatched as a myth quite some time ago. Many of the concepts behind firearm wounding (including full transfer of energy as fast as possible and temporary wound cavities for example) have kind of fallen the same way. I believe there's an FBI paper somewhere on the subject that - while now quite dated - makes a good read.

To knockback a moving target the bullet would need to stop a 150lb pile of meat, and then make it go backwards. Physics doesn't work that way, I'm afraid. If the target is badly off-balance: Sure. But that's a minority of situations.

The forces used in Aikido are FAR higher than that of a bullet. The acceleration of mass is fairly (deceptively) gentle, but the net forces required to throw people around are really quite huge, and don't forget the value of leverage: Pushing action to the upper outside shoulder will result in more torque than a bullet to the chest. Leverage is key in Aikido: As is making the other person do all the work.
Many of these forces are applied by the subject rather than the practitioner. For example; during kotegaishi, a tiny application of force triggers the subject to do most of the work themselves.

[Brainfart]

Katanas are actually hybrids, they work in both a slashing and chopping motion which is looser categorized as slashing.
A saber is actually more used as a chopping motion to take off limbs where a katana is best used to disembowel.

How does this make sense? Both blades function in the same manner. Their curvature imparts a drawing/slicing motion to the cut.

[Spiryt]

How does this make sense? Both blades function in the same manner. Their curvature imparts a drawing/slicing motion to the cut.

That would depends on how actually they work.... Because under the term "katana" one will find swords made over a good 1000 years, that can be quite different. And "saber" - well, this generally can mean thousand things.

Different length, cross section, taper, balance, edge, and stuff... Would define how they function.

The fact that both are curved, is just one not tremendously important detail, especially that while katanas were generally relatively similar in shape, sabers could curve in many different ways.

[fusilier]

That would depends on how actually they work.... Because under the term "katana" one will find swords made over a good 1000 years, that can be quite different. And "saber" - well, this generally can mean thousand things.

Different length, cross section, taper, balance, edge, and stuff... Would define how they function.

The fact that both are curved, is just one not tremendously important detail, especially that while katanas were generally relatively similar in shape, sabers could curve in many different ways.

There are even straight bladed sabers. The term saber is pretty arbitrary, and the most practical definition I've heard is a saber is basically a sword intended to be wielded on horseback. At least that seems to have been the military definition during the 19th century (sabers for horse, swords for foot). Thus some 19th century cuirassiers carried straight sabers. The distinction can be further confounded by circumstances: American Infantry officers in the mid 19th century generally preferred to carry a cavalry/dragoon saber rather than a sword.

Generally speaking cavalry sabers were curved, but the amount and style of curve could vary considerably as Spiryt pointed out.

[Yora]

Whats the benefit of a curved blade anyway?
I imagine you would have a smaller point of impact, but also a larger cutting surface compared to the length of the touching area. But what's actually the reason behind the two forms?

[fusilier]

Whats the benefit of a curved blade anyway?
I imagine you would have a smaller point of impact, but also a larger cutting surface compared to the length of the touching area. But what's actually the reason behind the two forms?

I've been told that it's easier to wield a curved blade when mounted.

[Spiryt]

Whats the benefit of a curved blade anyway?
I imagine you would have a smaller point of impact, but also a larger cutting surface compared to the length of the touching area. But what's actually the reason behind the two forms?

Heh, it's age old debate here....

Generally, I believe that when curved blade strikes at "optimal" angle, it simply faces the target with greater width of the blade, that it would in case of straight one. Drawing it even in crappy way on paper helps to illustrate that.

Therefore, sectional density, is greater, there is greater "push" of the steel behind the point of impact.

Now, this effect won't be generally that great in most cases, but still.

Generally, it's all about angles, geometry and shock. Different shapes will cause different uses of energy involved.

[bansidhe]

From what I,ve heard...the lighter the cavalry,the more curved the blade,basically cos your going faster[at least you should be],and it offers more cutting area in a passing slash.Not sure if this is technically true or not though.

[Galloglach where is you?! :) ]

[Tvtyrant]

It also has to do with which area of the blade you cut with. Straight blades you either stab with the tip or cut near the middle, while a curved blade can cut with forward third. If you tried to cut with the forward third of a straight blade it would jar your hands. This is one of the reasons curved blades are used in cavalry, you can cut with the area near the tip, so you can hit things within blade reach without worrying about your sword twisting in your hand. And since you can't stab from horseback without losing your sword in a charge anyway, a straight blade doesn't perform as well.

[Spiryt]

It also has to do with which area of the blade you cut with. Straight blades you either stab with the tip or cut near the middle, while a curved blade can cut with forward third. If you tried to cut with the forward third of a straight blade it would jar your hands. This is one of the reasons curved blades are used in cavalry, you can cut with the area near the tip, so you can hit things within blade reach without worrying about your sword twisting in your hand. And since you can't stab from horseback without losing your sword in a charge anyway, a straight blade doesn't perform as well.

Uh, actually with swords like Oakeshott type XIII, and many others, tip cuts would be of great importance... Quite obvious, looking at their rounded tips.

Jarring, vibrations, and whatever, depend on sword harmonics, and while of curvature of blades would produce different harmonics, there's nothing about straight blades that make them automatically more "shaky".

And actually "sweet spot" of most cutting straight blades tend to be much more forward than in the middle.

[Crow]

My experience with straight blades is that most cuts you are likely to land in a real fight are going to be with the last 6 inches or so of the blade. We're not talking about cutting straw mats here.

I can't imagine how this optimal point of impact with a curved blade is going to be much different than that of a straight one except in theoretical scenarios.

[Lapak]

I don't know for sure, but I imagine that curved blades are curved because of how slicing works mechanically. (All that follows is speculation; I am in no way an authority on this.)

Take a straight chef's knife and try to press the blade straight down through a loaf of bread. Unless the blade is literally razor-sharp, you don't get a slice of bread; you get a squished loaf of bread. Slide the blade straight across the top without any downward pressure, and you still don't get a slice: you get a loaf of bread with a shallow cut in it. You need to apply the pressure in two directions at once to get a good slice - both down and across.

A curved blade, by its very nature, is going to do that no matter how you cut: if you hit straight on, and the curve adds some sideways motion due to the shape, and if you slide across the surface, the curve will add some depth to the motion whether you're trying to or not.

Now, I imagine that most hits in a combat aren't going to be dead-on straight or across anyway, but a curved blade is going to be its own guide for better cutting on any hit.

[fusilier]

A butcher's cleaver can have a straight edge (or only a slight curve to it).

[Lapak]

A butcher's cleaver can have a straight edge (or only a slight curve to it).

Like I (tried to) say, it's not like you can't achieve a good cut with a straight or very slightly curved edge. The chef's knife is another fine example! But the targets of both cleavers and chef knives don't tend to be moving around like in combat, either, or creating unpredictable angles when you try to cut them.

(Also, note the disclaimer that I'm only speculating.)

[Spiryt]

Or rather, butchers knives are good at cleaving bones, which is their main purpose.

They also tend not to be long enough for curve to have much sense.

[MarkusWolfe]

A butcher's cleaver can have a straight edge (or only a slight curve to it).

Actually, if you look closely, you'll see that it's actually a short axehead with a knife's handle.

[Xuc Xac]

A curved blade, by its very nature, is going to do that no matter how you cut: if you hit straight on, and the curve adds some sideways motion due to the shape, and if you slide across the surface, the curve will add some depth to the motion whether you're trying to or not.

Almost but not quite. When you slice with a straight knife, you move the blade back and forth in a straight line. When you try to slice an opponent in combat, you do it by swinging the blade in an arc but you still want to draw the blade across the surface to be cut. With a straight blade, the blade will only be drawn straight across at one point of the arc. At the other points, it will be at an angle that is too high or too low for maximum slicing efficiency. A curved blade that matches the arc of the swing will allow the blade to be close to parallel to the target surface for the whole length of the cut. Some swords and knives have a very drastic curve (such as some Middle Eastern/Indian designs) because they are designed to be used up close with swings that pivot at the elbow and other swords have a shallower curve because they are designed to be used at arm's length with the shoulder as the main pivot.

[Deadmeat.GW]

If the target was moving (forward) it makes the physics even more unlikely.


Knockback due to physical force was kind of dispatched as a myth quite some time ago. Many of the concepts behind firearm wounding (including full transfer of energy as fast as possible and temporary wound cavities for example) have kind of fallen the same way. I believe there's an FBI paper somewhere on the subject that - while now quite dated - makes a good read.

To knockback a moving target the bullet would need to stop a 150lb pile of meat, and then make it go backwards. Physics doesn't work that way, I'm afraid. If the target is badly off-balance: Sure. But that's a minority of situations.

The forces used in Aikido are FAR higher than that of a bullet. The acceleration of mass is fairly (deceptively) gentle, but the net forces required to throw people around are really quite huge, and don't forget the value of leverage: Pushing action to the upper outside shoulder will result in more torque than a bullet to the chest. Leverage is key in Aikido: As is making the other person do all the work.
Many of these forces are applied by the subject rather than the practitioner. For example; during kotegaishi, a tiny application of force triggers the subject to do most of the work themselves.

Perhaps you should notice that I said KNOCKDOWN is described often by people watching as KNOCKBACK because of the optical effect of seeing something moving forward stop and drop on the spot.

[Spamotron]

I have a question about Modern Body Armor. I am given to understand that the problems of weight and restriction of movement are constantly being improved with new materials and armor designs. But that the building of excess body heat is somewhat more intractable. No material that will stop a bullet breathes very well.

That said personal under-suits with built in cooling have existed for years and are used by Race Car Drivers and Astronauts. I assume something makes them impractical for use with body armor. Is it just cost? or something else?

[Crow]

Every piece of kit adds to the overall weight that the soldier has to carry. While I am sure the suits are pretty light (anything in racing usually is), the other issue could be the cost. How much do these suits usually run?

[Spamotron]

Well after figuring out the right search terms I found water cooled vests that are intended for military use. Doesn't say if they fit under body armor though.

http://www.mscooling.com/militarycooling

[Psyx]

And since you can't stab from horseback without losing your sword in a charge anyway, a straight blade doesn't perform as well.

Straight blades work fine for thrusting on horseback. In fact, they were favoured by heavy cavalry in the Napoleonic period because they were 'killing swords', ideal for fighting mounted foes. Whereas the curved blade is better for light cavalry, making passing cuts, and striking at foes on foot.

Whats the benefit of a curved blade anyway?

A butcher's cleaver can have a straight edge (or only a slight curve to it).

And requires you to make a massive chop at things. Now take a filleting knife, simply press it gently against the same meat, and draw it, and you will cut just as deep, using less energy, and requiring less of a swing.

You don't cut cheese by hacking at it. Nor onions, nor tomatoes. You know that to cut well, you draw the blade along the cut and allow the edge to do the work; not your arm. The same is true with swords.

This is how curved blades work: They present a large amount of blade, and draw it across the target.

If you imagine grasping a straight blade with two hands and swinging at someone, you initially chop into them. Now draw the blade over the body in order to cut deeper, and the action is a little awkward and doesn't leave a long cut. If you perform the same cut with a katana, and then draw along the cut, pushing down and drawing, the action is a lot easier and leaves a longer, deeper cut.
This is why curved blades are good at slicing. The curve of the blade is designed expressly to optimise the cut.

Perhaps you should notice that I said KNOCKDOWN is described often by people watching as KNOCKBACK because of the optical effect of seeing something moving forward stop and drop on the spot.

I was expanding on a point, not arguing about or around it. Knock-down is primarily psychological in the majority of cases, and has little to do with energy.

That said personal under-suits with built in cooling have existed for years and are used by Race Car Drivers and Astronauts. I assume something makes them impractical for use with body armor. Is it just cost? or something else?

Race car drivers don't wear cooling suits. They wear nomex underwear. For a cooling suit to function for two hours in the cockpit of a single-seater, you'd need some form of heat exchange unit, which is extra weight and power drain from the engine.

Moving on to body-armour underwear, there are solutions out there. The first is the common sense one used by skiers and combat personnel alike: A wicking inner layer. Wear a breathable, well fitting under-garment that draws sweat away from your body, and allows your body's natural cooling system to function, instead of letting it sit in a pile of hot sweat. If you run a google on say' body armour under garments wicking', you'll see what I mean. There are dozens of types commercially available.

There are other solutions. Some private companies make vests which hold gel coolant packs: The kind you use to keep sandwiches cold. These don't need any heat exchange system or pumps, but have the drawback of only working for a couple of hours before needing to go back in the freezer.

The idea of carrying something heftier for a slight improvement is self-defeating in many ways. PBIs have to carry enough crud around with them to encumber them already. Adding to that just adds to the effort needed. And -frankly- you can wear a single layer of cotton in the Gulf, and you'll still be sweating copiously in the 45C+ heat. Nothing you can wear or do will stop you being overly hot and uncomfortable, short of a cold shower and a colder beer. Body armour makes it worse, but it's already a massive problem to start with. Best advice is just to carry as little extra kit as possible, and wear kit that lets your body cool itself properly. Any water in a cooling suit would serve better being in a canteen so you can drink the stuff and sweat it out.

[Stephen_E]

Apparently in WW2 The NZ Troops loved marching behind the US troops in Nth Africa because of all the kit the US soldiers would dump to reduce weight.
The NZ Troops would scoop it up (they were chronically poorly resupplied by the NZ govt )

Stephen E

[Storm Bringer]

ever since soldiers were centrally equipped, the PBI have dumped things they don't need and looked for ways to lighten thier load. during the days of Pike formations, the NCOs and officers had to be careful the troops didn't lop the lower ends off thier pikes for firewood. one captain lameted that, although the regulation length of pike was 18 feet, not one soldier in his unit had one over 15 feet, and if he didn't take care, they would be 12 feet long.

during the American civil war, the confederate troops often dumped thier 'wussy' issued bayonets in favour of thier bowie knifes and other personal melee weapons. recruits on both sides would dump thier heavy winter coats in the summer months and then complain when winter rolled around and they only had thier summer uniforms.

Troops in veitnam would take out the heavy truma plates form their flak jackets, and then get shot and rounds that might not have penatrated the jacket if the plates were in.


and on the amount of things modern soldiers carry, its freaking stupid. I've just come back off an exercise where, carrying everything i brought and the extra kit i had been given, it took two people to get me on my feet (I wasn't expected to fight carrying all this, but still, you get the idea). on overheating. it was October in Germany, thier was frost on the ground, i was sleeping outside, and ten minuites of marching was all it took to warm me up enough that i was comfortable in just my bofy armour and smock over the top.

[AslanCross]

Were Zweihanders ever used by warriors in full harness? All of the historical illustrations I've seen show them wielded by lightly-armored Landsknechts--usually in a breastplate or less.

[Kalaska'Agathas]

Why did breechloading firearms only become widely used (at least militarily) after the advent of the self contained cartridge? They are known to have existed since at least the 15th century, so I'm forced to wonder why they weren't widely adopted.

[PopcornMage]

Race car drivers don't wear cooling suits. They wear nomex underwear. For a cooling suit to function for two hours in the cockpit of a single-seater, you'd need some form of heat exchange unit, which is extra weight and power drain from the engine.

Well, NASCAR drivers might not use cooling circulation suits, but they do have air conditioning. Goes right in their helmet. They may have other cooling in the suit as well.

Sure, weight is an issue, but so is dehydration and heat exhaustion.

I'm sure the exact methods they use vary from driver to driver, and race to race, as well as league to league, but they do exist.

[Mike_G]

Why did breechloading firearms only become widely used (at least militarily) after the advent of the self contained cartridge? They are known to have existed since at least the 15th century, so I'm forced to wonder why they weren't widely adopted.

Several reasons. They were more expensive to produce, they were often prone to malfunction since they had more mechanics that could malfunction, and loose powder tended to foul the breech. It's not easy getting a good seal of the breech, so burning powder coming back at the user is a real issue. This was an issue as late as the Franco Prussian War in 1870. Brass cartridges solve a lot of these issues.

The Ferguson rifle tended to split the stock around the mechanism. No military Ferguson has been found without a repair to that area.

Plus, military doctrine and tactics took some time to evolve to where they could effectively deploy and supply troops with breechloaders.

Basically, the early breechloaders were fragile, expensive and prone to taking off your eyebrows. Not good selling points. A soldier wants a gun that goes bang when he pulls the trigger, and endangers the enemy more than it does him over one that promises great things but has "a few bugs."

Now, once the metal cartridge came into play in the mid 19th century, armies rapidly adopted breechloaders and repeaters.

[Storm Bringer]

also, metalurgy techology had to advance to the point were the manufacturing tolerances allowed a gas tight seal, and a gas tight seal that could be mass produced, at that (early breech loaders had hand crafted parts designed to fit each other, but were not interchangable with another rifle of the same type). it also had to be tough enough to take the punishment the average soldier can inflict upon his equipment (which, trust me, is LOTS). its no good having a gun that, as soon as it gets dropped/knocked over/blocks a sabre swing, requies a trip to the manufactures to repair it agian.

[Yora]

Were Zweihanders ever used by warriors in full harness? All of the historical illustrations I've seen show them wielded by lightly-armored Landsknechts--usually in a breastplate or less.

If you mean plate armor: certainly. There are some illustrations in the Fechtbücher which show two men in plate armor using longswords.

This is the one I was thinking of: http://upload.wikimedia.org/wikipedi...rstein_219.jpg