Splitting Bullets

[pomeroo]

One of the no-planes loons sent me this video:
http://au.youtube.com/watch?v=mIDWG9Zn8j8 (http://au.youtube.com/watch?v=mIDWG9Zn8j8)

The Japanese guy is very funny, but I'll admit to being curious about the splitting of the bullet by the sword. Is the whole thing merely a fake, or is there an explanation for the lack of damage to the sword? Does the angle of the strike minimize the surface area of the blade to such a degree that it receives little force?

Would one of our resident physics gurus enlighten me?

[Arus808]

the guy dubbing for the nihonto really had to do that fake japanese accent. oy vay

[beachnut]

One of the no-planes loons sent me this video:
http://au.youtube.com/watch?v=mIDWG9Zn8j8 (http://au.youtube.com/watch?v=mIDWG9Zn8j8)

The Japanese guy is very funny, but I'll admit to being curious about the splitting of the bullet by the sword. Is the whole thing merely a fake, or is there an explanation for the lack of damage to the sword? Does the angle of the strike minimize the surface area of the blade to such a degree that it receives little force?
Would one of our resident physics gurus enlighten me?Real! but watch the 50 cal.
Lead bullets! But watch what happens when the sword meets a high speed impact. It seems the sword was like the WTC, a slow speed impact is okay, a high speed impact is not! Kind of proves 9/11 is true.

http://au.youtube.com/watch?v=-sHTJAKN-5k&feature=related

-sHTJAKN-5k Oops, no more sword.

But Tbone is right - it took some hits!

[Tbone]

I was always quite amazed at how well that sword did against a .50 calibre machine gun.

[chillzero]

Moved to General Skepticism, as not a CT

[Spud1k]

Nice video. It was painful to see such a fine sword get destroyed but it put up a valiant battle.

[Confuseling]

And you can play at home too with a chefs knife and a tennis ball!


[kids - ignore everything your read on the internet]

[TheDaver]

Definitely real. And nothing particularly special about the sword either.

Splitting bullets against hatchets is an old gun show trick.

When you think about it, it makes sense. The bullet’s soft and the sword/hatchet/butterknife is hard. Which one do you think is going to win?

[Horatius]

Is the whole thing merely a fake, or is there an explanation for the lack of damage to the sword? Does the angle of the strike minimize the surface area of the blade to such a degree that it receives little force?




Well, there isn't really a "lack of damage", as the sword vs. machine gun video shows. It's just that one bullet by itself doesn't do enough damage to show.

Also, remember with a katana, the edge is designed to be the hardest steel, while the bullet is much softer. And the angle does matter - if you don't hit the sharp edge square on, the sword won't cut very much, if at all. Bullet vs. flat side of sword would go much worse for the sword.

[Confuseling]

...though I shouldn't imagine it would do the bullet much good either :)

[rwguinn]

Stress is force/area. The area of contact between the bullet and sword is very small, and the force quite large.
Failure stress for lead is tiny, compared to the sword steel.
No surprises there...

[pomeroo]

Stress is force/area. The area of contact between the bullet and sword is very small, and the force quite large.
Failure stress for lead is tiny, compared to the sword steel.
No surprises there...


Thanks for confirming what I intuited. The decision to move this thread out of 9/11 conspiracies is odd, to say the least. My first sentence explains that the video was sent to me by a no-planer, which should have been a clue to the thread's province. The dead horse these loons flog ceaselessly reveals their misunderstanding of basic physics. They really do not believe that a 120-ton projectile moving at roughly 500 mph could sever the external columns and penetrate the facade of the tower.

[neutrino_cannon]

OK, I'll bite.

How on earth was this extrapolated to mean that there were no planes?

[pomeroo]

OK, I'll bite.

How on earth was this extrapolated to mean that there were no planes?


Ah, this is the question you're supposed to ask! You see, the sword splitting the bullet "proves" that a softer substance cannot possibly damage a harder one. Ergo, the aluminum planes couldn't possibly have severed the steel columns.

If you've never seen the equation F=MA, this might make sense. The no-planes loons completely ignore the implications of a 120-ton projectile moving at 500 mph. Apparently, the force it generates means nothing.

[neutrino_cannon]

Ah, this is the question you're supposed to ask! You see, the sword splitting the bullet "proves" that a softer substance cannot possibly damage a harder one. Ergo, the aluminum planes couldn't possibly have severed the steel columns.

If you've never seen the equation F=MA, this might make sense. The no-planes loons completely ignore the implications of a 120-ton projectile moving at 500 mph. Apparently, the force it generates means nothing.

Because the construction of a skyscraper and a katana are so comparable. I hear that the wavy pattern you see on the outside of skyscrapers comes from when you case-harden the entire building to enhance its cutting power. I also understand that katanas are mostly concrete by weight, and that the steel is only added to improve tensile strength...

[Bikewer]

These sorts of videos pop up on the Mythbusters forum all the time. No big deal to splitting bullets, as Davey says; it's a standard "sharpshooter" trick that's been done for many years.

Doesn't even have to be sharp; any old hatchet will do nicely.

Some one mentioned the .50 BMG round; a video circulating months ago (also Japanese) purported to show a .50 machine gun destroying an "inferior" sword, but the "superior" sword split the .50 caliber bullet.

It was an obvious fake, anyone with any knowledge of such things would have seen the slo-mo footage of the bullet being split was not, in fact, a .50 BMG round, but a round-nosed lead bullet of large caliber; likely a 45-70 or somesuch.

[neutrino_cannon]

There's the video above of the .50 BMG destroying a sword... after multiple hits. Is .50 ball ammo steel-cored? That could have something to do with it.

Anyway, I'm still unclear on how throwing a 230 grain piece of lead at the sharp, thin end of a springy, face-hardened piece of solid steel is remotely applicable to throwing several tons of aluminum and jet fuel at a building.

[tyr_13]

OMG! Finally! A subject that I might actually know more about than the super-smart people on these forums! I'll post a longer explanation after work, but it actually has a lot to do with the way katana's are constructed, and the way a lead bullet works as well. Blade geometry and material comes into play. For now, let me just say that it is because both the blade and the bullet are doing what they were designed to do.

[neutrino_cannon]

OMG! Finally! A subject that I might actually know more about than the super-smart people on these forums! I'll post a longer explanation after work, but it actually has a lot to do with the way katana's are constructed, and the way a lead bullet works as well. Blade geometry and material comes into play. For now, let me just say that it is because both the blade and the bullet are doing what they were designed to do.

I didn't see enough of the bullet to say whether it was an expanding point design or not.

I would fully expect similar results with FMJ rounds, however.

[Horatius]

Ah, this is the question you're supposed to ask! You see, the sword splitting the bullet "proves" that a softer substance cannot possibly damage a harder one....



So long as the harder one has a sharp edge.....


So, ask him to compare and contrast a katana and a steel box column.


It would almost certainly produce a few good Stundies!

[Confuseling]

So long as the harder one has a sharp edge.....


And is hit slow enough. Isn't it a commonplace NASA quote that a marshmallow could take a satellite out of orbit?

[Mongrel]

What about a blunt, breakable objects 'impaling' solid objects?
Wouldn't that disprove their 'theory'?
This (http://images.google.com/imgres?imgurl=http://www.nasa.gov/images/content/116676main_plank_palm_lg.jpg&imgrefurl=http://www.nasa.gov/vision/earth/lookingatearth/halverson_paper_prt.htm&h=595&w=400&sz=55&hl=en&start=1&tbnid=tnIBlQkP66hUQM:&tbnh=135&tbnw=91&prev=/images%3Fq%3Dplank%2Bthrough%2Btree%26hl%3Den%26sa fe%3Doff)is a fairly standard post hurricane picture...

[Ranb]

It is hard to tell what kind of ammo they were using for the machine gun test. 51 caliber bullets for the M2 are available in copper jacketed lead, copper jacketed steel (military ammo) and solid bronze or brass. I think I saw some of the bullets hit the blade and strip the copper jacket off, but not directly impact the blade with the steel core, if that is what they were using.

I've shot enough metal targets to know that a steel core bullet is going to destroy any hand held sword with one direct hit. But carbon steel plow blades laugh at armor piercing bullets. :)

Ranb

[tyr_13]

I didn't see enough of the bullet to say whether it was an expanding point design or not.

I would fully expect similar results with FMJ rounds, however.

It doesn't have to be an expanding bullet to work. The blade geometry of a katana is different from most any other modern blade. It isn't flat ground, or hollow ground. The shape is kind of like that of the spade on the ace of spades toward the blade. When used in the draw cut, this shape not only is very strong (not so sharp) but will bloom the flesh (or lead) outward. This effect makes it cut deeper because the flesh doesn't press against the sides of the blade slowing it down. Against the bullet, it keeps the lead away from the sides of the blade. The bullet appears to be a full lead one. It would likely work with jacked ammunition too, but with more marring on the blade.

A differential temper helps too. That is what produces the beautiful hamon line. The blade is hard, but more brittle. The backing is flexible. When the bullet hits the hard front, a lot of the energy is transferred to the back, softer steel which works like a spring. If the back was of the same hardness as the front, it would snap.

This trick can be done with other wedges as well, like ax blades. It works with them because they are laterally thick. Normally though it is done with .22 rounds, not .45 acp.

As far as evidence for the no plane thing, well...it is insanely stupid. It has no relation at all, and you'd have to know very little about metal, physics, and reasoning in general to believe it did.

[X]

SwordForum.com (http://forums.swordforum.com/showthread.php?t=75440) has a thread on the subject.

Not much in the way of outright skepticism, I'm sorry to say, but some good points raised nonetheless.

You can also search the forum for more info.

[TheDaver]

...though I shouldn't imagine it would do the bullet much good either :)
Almost nothing ever does. They’re only made for one trip, one way, after all.

[Bikewer]

Standard military AP (armor piercing) rounds for the .50 BMG normally have a core of hardened steel or tungsten surrounded by enough lead to fill the space inside the jacket.

Just for trivia's sake, the jacket is made of a material called "gilding metal", which is a copper alloy.

[billydkid]

You can definitely split a bullet with a blade. Marksmen do this all the time in demonstrations.

[neutrino_cannon]

Standard military AP (armor piercing) rounds for the .50 BMG normally have a core of hardened steel or tungsten surrounded by enough lead to fill the space inside the jacket.

Just for trivia's sake, the jacket is made of a material called "gilding metal", which is a copper alloy.

Thanks, I couldn't remember if there was an armor-penetrating core in .50 ammo standard or not.

The actual composition of the "lead" in other ball ammo varies too; it's usually hardened with antimony.

Still, nothing that's a match for a steel blade.

Would be interesting, at the risk of screwing up a bunch of pretty katanas, to try this test with 5.56mm ball. Would it split or fragment, I wonder?

[Bikewer]

Back when I was casting bullets, we used both tin and antimony as hardening agents. This required the constant addition of a "flux" to the melted lead to keep the metals from separating.
The "gold standard" for cast bullets was always linotype metal. This is hard stuff, my brother-in-law at the time got a 10 pound ingot. He dropped it and it broke!

[Confuseling]

Almost nothing ever does. They’re only made for one trip, one way, after all.

True enough. Darn consumerism. What was wrong with pointy rocks?

[DarthFishy]

Well don't let the no-planers ever see the video of the Mythbusters testing what happens when you fire a bullet into water (at an angle of +- 30 degrees). The .50 cal bullet completely disintegrated if I remember correctly.

[Spud1k]

Well don't let the no-planers ever see the video of the Mythbusters testing what happens when you fire a bullet into water (at an angle of +- 30 degrees). The .50 cal bullet completely disintegrated if I remember correctly.

Man.... if the truthers start trying to use mythbusters as a source of info, that would be so far off the irony-o-meter it'd be scary. Where could they go after that? Snopes?

[TheDaver]

Well don't let the no-planers ever see the video of the Mythbusters testing what happens when you fire a bullet into water (at an angle of +- 30 degrees). The .50 cal bullet completely disintegrated if I remember correctly.
The standard CF response to anything Mythbusters-related is that they’re disinfo agents paid by the US guvvermint.

[technoextreme]

Ah, this is the question you're supposed to ask! You see, the sword splitting the bullet "proves" that a softer substance cannot possibly damage a harder one. Ergo, the aluminum planes couldn't possibly have severed the steel columns.

That's stupider than the beam weapons. Anyway argument destroyed with three words: Water jet cutter. I wish I could find out what weapon it was but presumably you knock a hole in a wall with water and explosives. I saw that on an episode of Future Weapons. Water cannons are commonly used to destroy bombs.

[Ranb]

Well don't let the no-planers ever see the video of the Mythbusters testing what happens when you fire a bullet into water (at an angle of +- 30 degrees). The .50 cal bullet completely disintegrated if I remember correctly.

I watched that episode. It seems they pulled the jacket out of the water and could not find the steel core. The pieces of jacket they had looked like what is left in front of a metal target when it is shot with steel core ammo.

Ranb

[ponderingturtle]

That's stupider than the beam weapons. Anyway argument destroyed with three words: Water jet cutter. I wish I could find out what weapon it was but presumably you knock a hole in a wall with water and explosives. I saw that on an episode of Future Weapons. Water cannons are commonly used to destroy bombs.

No there is a better trivial case.

Glass is very hard, lead is very soft, so windows should stop soft lead bullets every time.

Also when cutting hard materials water jets often use abrasives.

[ponderingturtle]

I watched that episode. It seems they pulled the jacket out of the water and could not find the steel core. The pieces of jacket they had looked like what is left in front of a metal target when it is shot with steel core ammo.

Ranb

DId their bullets have a steel or lead core?

[Damien Evans]

I think this person has somehow confused themselves with mohs scale. Mohs scale is not applicable to planes hitting buildings, needless to say.

[neutrino_cannon]

True enough. Darn consumerism. What was wrong with pointy rocks?

Inferior sectional density and too brittle and hard. It would screw up the bore as it came apart.

Besides, the case, which represents a lot of the material in modern ammunition can be recycled.

Bikewer, do you happen to have any more information about the "flux" in linotype metal? I'm curious.

[Ranb]

DId their bullets have a steel or lead core?

The ammo appeared to be military surplus ball (M33). This stuff has a steel core. But I can not be sure.

Ranb

[R.Mackey]

One of the no-planes loons sent me this video:
http://au.youtube.com/watch?v=mIDWG9Zn8j8 (http://au.youtube.com/watch?v=mIDWG9Zn8j8)

The Japanese guy is very funny, but I'll admit to being curious about the splitting of the bullet by the sword. Is the whole thing merely a fake, or is there an explanation for the lack of damage to the sword? Does the angle of the strike minimize the surface area of the blade to such a degree that it receives little force?

Would one of our resident physics gurus enlighten me?

I'd missed this thread earlier, but as others have noted, it's not a hoax, and it's very simple.

The blade is edge-on to the machine gun fire. That's critical. Very little of the bullet's momentum is being absorbed by the blade. You really would not want to be standing behind the sword while this was going on.

If you were to turn the blade sideways, such that it actually had to stop one of those bullets, it would snap at once.

The way to treat this numerically, as I've mentioned elsewhere a few million times, is to consider the pressure-impulse of the impact. Here, where the bullet is being split, pressure is very high, but the impulse is slight, probably not more than a few percent of the total momentum of the bullet. Steel is a nice, resilient material, particularly ultra-high grade steel such as a finely made katana, so it can tolerate high stresses provided it's only for a brief instant.

If you overload it enough, of course, it can also snap from sheer pressure. Or, as we see here, it gets eroded. This erosion is actually the dominant effect in high-velocity penetrators, i.e. APFSDS rounds in tank warfare. Such effects govern the materials used, along with density, which provides the highest pressure for a given total impulse, and the most streamlining, which retains impulse at the furthest distance possible.

In the WTC Towers case, which I'm sure your opposition was referring to, we see both effects. Where pressure is highest, i.e. leading edge of the core columns, they can fail. But the next row of columns in generally survives. There is still material hitting them, but there it passes to the sides, as the pressure is diminished. Survival or failure under these conditions is a very brittle phenomenon (i.e. "all or nothing") as the final demise of the katana demonstrates.

[neutrino_cannon]

Thanks R.Mackey. Given that, how effective would a non-load bearing outer structure be in allowing a building to survive plane strikes? I'm thinking something like a Whipple shield that breaks up the plane to reduce erosive pressure on the load bearing components.

[R.Mackey]

The Whipple shield is one approach, another slightly better approximates slat armor (http://en.wikipedia.org/wiki/Slat_armor). But one needs to be mindful of unintended consequences.

The effect of outriding elements will not be quite the same as the Whipple shield simply because the impacts here are well below the speed of sound in the material, and the impacting object is large compared to any reasonable spacing. Some initial breakup is desirable, but you may also inadvertently contain combustibles etc. that otherwise might pass through or be more favorably dispersed.

There is also the question of whether you even want your structural elements to survive. Should the structure basically side-step the impact, and allow the contents to be utterly destroyed? Or would you rather absorb the impact and contain it?

A useful parable is the Pentagon impact. There was a limited collapse there as well, but very limited, with only a few columns actually being destroyed. This is due to a harder outer shell, more massive masonry facade that added no strength but served as a momentum sink, and also due to the massive, spirally reinforced concrete columns. These columns were well designed to absorb energy, and this helped prevent the spread of debris, perhaps saving the structure from much more serious fire damage later.

There are a few simple things one can do in ordinary structures. Instead of hollow steel shapes, use round solid ones. This will have some cost in buckling strength and so on, so perhaps a compromise star-shape and a little less efficient structure will result. Also, a more traditional post-and-beam structure, with many rows of columns rather than widely spaced perimeter and core, is thought by many (Dr. Astaneh-Asl in chief) to be more resistant to impact.

What the response seems to be so far is a return to concrete cores and more concrete framing of steel members. This makes collapse due to fire much less likely, and also has the added benefit of providing protected stairwells, for instance, but it comes at a substantial penalty in cost and usable floor space. Lots of ideas are being tried by architects, we'll see if anyone hits upon a winning formula.