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Shaped Charges – Sheet of copper going through 1ft of solid steel (2010) [video]

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Re: Shaped Charges – Sheet of copper going through 1ft of solid steel (2010) [video]

#151

Post by chemeril »

lazide wrote: post #144
chemeril wrote: post #124

Earlier quoted context omitted.

It is not. Nitroglycerin doesn't have the capacity to detonate (necessary for triggering the main charge). Detonators (the acceleration charge you mention) are usually an explosive train starting with a sensitive primary like lead azide moving up to a secondary or pseudosecondary output charge like PETN.

Oh man lol. Nitroglycerin most certainly has the power to initiate even a insensitive explosive like RDX, PETN, etc. It's detonation velocity is ~ 7700m/s. It's just very unstable which is why it isn't used raw. A jostle or turning the stopper on the bottle it's in can set it off. The less pure it is, the more dangerous it is. It's detonation velocity is twice as high as lead azide for instance. Nitrocellulose can al…

GP's comment was referencing nitrocellulose, which is what I was attempting to address but fatfingered to 'nitroglycerin'. Forgive the typo.

Re: Shaped Charges – Sheet of copper going through 1ft of solid steel (2010) [video]

#152

Post by kayodelycaon »

itsyaboi wrote: post #96
mhh__ wrote: post #91

Earlier quoted context omitted.

The younger guy in this clip actually ended up retiring because he got brain damage in a contraption he designed for this show. https://www.bbc.com/news/uk-58762935

This is bizarre. He knowingly, purposefully took the place of a crash test dummy? Why?

I assume he was focused on doing the experiment he (and dozens of other people) lost sight of the consequences.

As we say in America: “Hold my beer.”

Edit: Or more charitably, they underestimated the consequences.

Re: Shaped Charges – Sheet of copper going through 1ft of solid steel (2010) [video]

#154

Post by sacrosancty »

itsyaboi wrote: post #96
mhh__ wrote: post #91

Earlier quoted context omitted.

The younger guy in this clip actually ended up retiring because he got brain damage in a contraption he designed for this show. https://www.bbc.com/news/uk-58762935

This is bizarre. He knowingly, purposefully took the place of a crash test dummy? Why?

Apparently they used to do that. Here are people demonstrating the safety of seatbelts by crashing their car https://www.youtube.com/watch?v=GWy0hHHECdM

Re: Shaped Charges – Sheet of copper going through 1ft of solid steel (2010) [video]

#155

Post by root_axis »

hunter-gatherer wrote: post #136

In the US/Iraq war such contraptions were commonly referred to as EFPs (explosively formed penetrators). My platoon was once hit by a four-array EFP that was hung behind a cement wall (US forces would often line streets with barricades like this) so we couldn't see it. It went through the concrete wall, the humvee, and took some legs with it. Brutal things they were. We avoided prolonged truck excursions, but I remem…

That sounds pretty scary. I hope you made it out ok.

Re: Shaped Charges – Sheet of copper going through 1ft of solid steel (2010) [video]

#156

Post by sacrosancty »

throw_away wrote: post #102
WhitneyLand wrote: post #34

Earlier quoted context omitted.

It’s not molten, and heat plays no role in the penetration ability. This is a very common misconception. It’s simply focused kinetic energy that does it. The cone focuses the copper into a slug like object, and the slug becomes similar to an extremely powerful bullet.

What would happen if you just started with a slug?

I don't think you could deliver as much energy to it because it has such a small surface area normal to the direction of travel.

Re: Shaped Charges – Sheet of copper going through 1ft of solid steel (2010) [video]

#157

Post by blip54321 »

chemeril wrote: post #118
blip54321 wrote: post #67

Question: Is there a way to play with these things at home? Any pointers to DIY stuff?

Yes and no. It's simple enough to construct a shaped charge from things you buy at Home Depot, assuming you have the right explosive. The explosive needs to be conformal (either plastic or castable) and capable of achieving true detonation. Secondaries like C4 and TNT are not easy to synthesize at home, and the primaries that are easy to synthesize at home are difficult to phlegmatize and handle safely at the necessa…

I'd like to mess with them at home, but not at "the necessary volumes" to go through a foot of steel as in the video.

You know those little bang snaps you throw at the ground and they make a popping sound? For DIY, ideally, I'd do things in that kind of volume. I'd probably need a smidgen more, but I wouldn't want to do more than e.g. make a pinhole in 29 gauge sheet metal.

What I'd really love to make -- but I don't think I ever could safely -- is a little 1/8A or 1/4A rocket engine (of the that cost a couple bucks at the local hobby store).

This is science lab with kids, not bomb-making 101.

Re: Shaped Charges – Sheet of copper going through 1ft of solid steel (2010) [video]

#158

Post by User23 »

nostrademons wrote: post #107

The Wikipedia article on shaped charges is fascinating: https://en.wikipedia.org/wiki/Shaped_charge The penetration distance is proportional to the diameter of the charge (counterintuitive; you'd expect the height), and can be up to 7x as large. So a ~5 inch charge shown in the film can penetrate up to about 3 feet of solid steel. Also, all of our known defenses against shaped charged rely on the assumption that the…

Training with shaped charges made my father grateful he ended up in the infantry. They are clever, but seriously nasty.

Re: Shaped Charges – Sheet of copper going through 1ft of solid steel (2010) [video]

#159

Post by green-eclipse »

itsyaboi wrote: post #96
mhh__ wrote: post #91

Earlier quoted context omitted.

The younger guy in this clip actually ended up retiring because he got brain damage in a contraption he designed for this show. https://www.bbc.com/news/uk-58762935

This is bizarre. He knowingly, purposefully took the place of a crash test dummy? Why?

"Hi, I'm Johnny Knoxville and this is crash test humans"

Re: Shaped Charges – Sheet of copper going through 1ft of solid steel (2010) [video]

#160

Post by supernova87a »

htk wrote: post #131
matheusmoreira wrote: post #106

Earlier quoted context omitted.

> The injuries happened when Mr Stansfield, who was 42 at the time, filmed a Bang Goes The Theory feature about the relative safety of forward and rear-facing child car seats. > The episode saw him "strapped into a rig like a go-cart which was propelled along a track into a post". I'm sorry but to me this reads like something out of Darwin Awards.

That’s why he was awarded around half of what he demanded, because BBC shared the responsibility by accepting the stunt, but he was also responsible for doing it.

Doesn't the BBC contract out to production companies so that they're not liable as a huge organization for one small show's dumb actions? Seems odd, but maybe that's not a thing in the UK.
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