Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

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

youtube.com

Post reply on HN
Print view View original

21–30 of 306 posts

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

#21

Post by giantg2 »

Vladimof wrote: post #15
giantg2 wrote: post #7

If you're going to play around with explosives, an old knowledgeable teacher is best. I imagine incompetence gets weeded out early. The guy in the video has been in quite a few others too. It's fun to see how the hosts are usually a little nervous and he's calm as can be.

This type of explosive is very stable... nothing like nitroglycerin ...

The explosive is stable (small cubes of most plastic explosive can even be lit on fire and act as fuel). But there is still danger in correctly handling/connecting the detonator. I'm not sure, but I thing the acceleration charge might be a less stable type as well (obviously they aren't going to give us step by step instructions).

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

#22

Post by raldi »

nine_k wrote: post #20
daenz wrote: post #16

I'm not sure I fully understood the explanation. So the copper cone is turned inside out and turns into a pointed wire that drives into the target? How is it that this wire can continue through the 1ft of steel? Is the force of the explosion flowing through this wire/tube, like liquid in a straw? And somehow it can sustain this through 1ft of steel?

Update: this is incorrect . The cone becomes very hot stream of molten copper. It melts through the steel plate, much like a jet of hot water melts through a block of ice. This happens fast enough that much heat does not have the time to escape from the impact site, despite high thermal conductivity of metals. The high pressure created by the explosion keeps the jet compressed from sides, too, so it does not fragment…

The video specifically says it’s not molten.

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

#23

Post by qbasic_forever »

londons_explore wrote: post #6

This is just a few dollars worth of copper and explosives. Attach it to a few tens of dollars worth of drone. (The cheapest drones are under 10 dollars now). A country could release 1000 of these and direct them at any military target, and they'll do massive amounts of damage at very low costs. Most anti-drone defences can be defeated simply with a redesign of the drone (eg. Use UWB for Comms, and have dual gyros and…

Loitering anti-tank munitions are basically just that--a drone with shaped charges that fire down. Russia actually has a mine that detects the seismic profile of a tank rolling nearby, launches a drone (of sorts) into the air, and shoots a shaped charge right down into the tank (where there's very little armor compared to the sides): https://www.youtube.com/watch?v=zqtFhqSNubY

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

#24

Post by causality0 »

nine_k wrote: post #20
daenz wrote: post #16

I'm not sure I fully understood the explanation. So the copper cone is turned inside out and turns into a pointed wire that drives into the target? How is it that this wire can continue through the 1ft of steel? Is the force of the explosion flowing through this wire/tube, like liquid in a straw? And somehow it can sustain this through 1ft of steel?

Update: this is incorrect . The cone becomes very hot stream of molten copper. It melts through the steel plate, much like a jet of hot water melts through a block of ice. This happens fast enough that much heat does not have the time to escape from the impact site, despite high thermal conductivity of metals. The high pressure created by the explosion keeps the jet compressed from sides, too, so it does not fragment…

It's not actually liquid, it only behaves like one on impact due to the magnitude of the forces. It's more accurate to say it erodes through the armor instead of melting.

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

#25

Post by Vladimof »

nine_k wrote: post #20
daenz wrote: post #16

I'm not sure I fully understood the explanation. So the copper cone is turned inside out and turns into a pointed wire that drives into the target? How is it that this wire can continue through the 1ft of steel? Is the force of the explosion flowing through this wire/tube, like liquid in a straw? And somehow it can sustain this through 1ft of steel?

Update: this is incorrect . The cone becomes very hot stream of molten copper. It melts through the steel plate, much like a jet of hot water melts through a block of ice. This happens fast enough that much heat does not have the time to escape from the impact site, despite high thermal conductivity of metals. The high pressure created by the explosion keeps the jet compressed from sides, too, so it does not fragment…

> much like a jet of hot water melts through a block of ice

cold water can cut through steel also...https://www.youtube.com/watch?v=v0NVOThRooE

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

#26

Post by postalrat »

nine_k wrote: post #20
daenz wrote: post #16

I'm not sure I fully understood the explanation. So the copper cone is turned inside out and turns into a pointed wire that drives into the target? How is it that this wire can continue through the 1ft of steel? Is the force of the explosion flowing through this wire/tube, like liquid in a straw? And somehow it can sustain this through 1ft of steel?

Update: this is incorrect . The cone becomes very hot stream of molten copper. It melts through the steel plate, much like a jet of hot water melts through a block of ice. This happens fast enough that much heat does not have the time to escape from the impact site, despite high thermal conductivity of metals. The high pressure created by the explosion keeps the jet compressed from sides, too, so it does not fragment…

Maybe that's what happens but the video explains it as a stream of copper (not molten?) that pushes the steel out of the way.

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

#28

Post by KennyBlanken »

trhway wrote: post #19
daenz wrote: post #16

I'm not sure I fully understood the explanation. So the copper cone is turned inside out and turns into a pointed wire that drives into the target? How is it that this wire can continue through the 1ft of steel? Is the force of the explosion flowing through this wire/tube, like liquid in a straw? And somehow it can sustain this through 1ft of steel?

due to the copper cone shape and the explosion wave propagation from the back the copper, which at those pressures is flowing like a liquid, is formed into a jet and pushed forward like a water in a power washer hose. Water at 3000bar would cut several inch steel ( https://www.youtube.com/watch?v=quL14Csmi_Y ). The copper in that explosion gets accelerated to the speeds of like 10km/s and as a result cuts through eve…

FYI, waterjets cut by using water to carry an abrasive media which is injected into the stream at/near the nozzle, not by the action of the water alone.

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

#29

Post by h2odragon »

giantg2 wrote: post #7

If you're going to play around with explosives, an old knowledgeable teacher is best. I imagine incompetence gets weeded out early. The guy in the video has been in quite a few others too. It's fun to see how the hosts are usually a little nervous and he's calm as can be.

Count the fingers. More than 8 is probably OK. age may be a drawback, one gets too old to meddle with some of the more fun things eventually.

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

#30

Post by dragontamer »

alkonaut wrote: post #11
londons_explore wrote: post #6

This is just a few dollars worth of copper and explosives. Attach it to a few tens of dollars worth of drone. (The cheapest drones are under 10 dollars now). A country could release 1000 of these and direct them at any military target, and they'll do massive amounts of damage at very low costs. Most anti-drone defences can be defeated simply with a redesign of the drone (eg. Use UWB for Comms, and have dual gyros and…

Something that carries say 1kg for any distance, is a pretty significant drone. The Dji Mavic pro can carry 1kg and is around $1k. > I think the only reason we haven't seen this on the battlefield yet is that we haven't yet had a war between the right countries. But we will. There are videos every day of Ukrainian drones dropping shaped charges like the Russian RKG-3/1600 from drones. Ukraine even has special troops…

1kg is similar to smaller warheads in the AT4 anti-tank weapon.

But AT4 is not reliable, only 400mm of penetration and tanks can have 500mm or 600mm of armor. (Or really, equivalent to 500+mm once special materials or geometry is factored in).

To reliably kill a main battle tank requires a larger munition. Javelin is a 8kg warhead IIRC. This is because Javelin is tandem: two warheads. First warhead destroys reactive armor, 2nd warhead actually kills the tank with 900mm of penetration.

---------

For drones to be optimized on the battlefield will require specially designed drones and special warheads designed to fit in the cargo-capacity of drones.

Switchblade 300 is nice for example but is too small to reliably kill a tank.

Switchblade 600 can kill a tank, but no longer has the small and lightweight form factor that I'm sure the soldiers who have to carry this crap care about.

Post reply on HN