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Author: Subject: Unconventional Shaped Charges
greenlight
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[*] posted on 18-9-2015 at 01:34


Nice test Nux, but damn plate, we still don't know where your charge stands on the graph because one of the welds broke which would have affected the jets performance I'm guessing. Even though it broke you still got more depth so it can go deeper.
Just goes to show how much energy these jets carry if they can break the welds that they don't even contact:D

For a charge 3x standoff and 4 CD penetration, it stands around non-precision line at the moment but I think you could get over it if the plates didn't break apart at the weld.


[Edited on 18-9-2015 by greenlight]




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[*] posted on 18-9-2015 at 02:39


The 5 plates were scattered over a half meter it just blew it to shit.
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[*] posted on 18-9-2015 at 02:52


:D
Where all the plates welded together?
If so, did it break all the welds between the plates?




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[*] posted on 18-9-2015 at 02:56


All 5 plates were tacked welded on 4 corners so it broke 18 tacks in total,where the carrot pokes through it only broke 2 tacks so 4x4= 16+2=18 a lot of tacks anyway. :(

[Edited on 18-9-2015 by nux vomica]
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[*] posted on 18-9-2015 at 04:50


Very interesting, do you have a density measurement for the plastic explosive mix you are using at the moment for that charge?



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[*] posted on 18-9-2015 at 10:12


Very nice!

I would increase standoff even more. That first hole is pretty big. It takes a lot of energy to punch a hole that size. If you increase standoff, you'll reduce the size of that initial hole and you'll have more energy available for penetration.
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[*] posted on 18-9-2015 at 20:14


Quote: Originally posted by gnitseretni  
Very nice!

I would increase standoff even more. That first hole is pretty big. It takes a lot of energy to punch a hole that size. If you increase standoff, you'll reduce the size of that initial hole and you'll have more energy available for penetration.


Hmm ive got another piece of pvc pipe and 10 grms of etn plastic left so I think the next ones standoff will be 5.5cd or 110mm thoughts?

[Edited on 19-9-2015 by nux vomica]
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[*] posted on 18-9-2015 at 21:36


Quote: Originally posted by greenlight  
Very interesting, do you have a density measurement for the plastic explosive mix you are using at the moment for that charge?


Its 1.26 grams per cubic centermeter greenlight
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[*] posted on 21-9-2015 at 07:28



Quote:

Its 1.26 grams per cubic centermeter greenlight


Really? That is surprisingly good performance for such a low density.
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[*] posted on 21-9-2015 at 10:26


How did you determine density? Did you further process the plastique after that measurement, possibly changing the density?



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[*] posted on 21-9-2015 at 15:00


Quote: Originally posted by nux vomica  


Its 1.26 grams per cubic centermeter greenlight


That seems a tad bit low actually, at least for such excellent results....perhaps a characteristic peculiarity in the measurement technique is responsible for that. I've never overworked my plastiques too much with the rolling and homogenisation, but still the density (by water displacement method) seems to land in the vincinity of 1.4g/cm3




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[*] posted on 21-9-2015 at 15:13


Unfortunately after checking my etn plastic my earlier post was the wrong density measurement :( I mismeasured the aluminium tube dia and being a small dia and etn weight it made a large difference to the result.

I remade my density measuring tool to measure 10 grams, I reamed a 20mm hole in some delrin and made a base and plunger to suit it and found it actually measured 1.417 grms cm3 density .

The etn plastic pellet measures 20 mm dia by 22.46 long so 3.141 x sqr10 x 22.46 = 7.056 cm3
10 grams / 7.056 cm3 = 1.417grms cm3

So it seems my etn plastic is a reasonable density for shaped charges after all, nux



20150922_164200.jpg - 1.4MB 20150922_162656.jpg - 1.1MB 20150922_162801.jpg - 1.1MB

[Edited on 22-9-2015 by nux vomica]
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[*] posted on 24-9-2015 at 19:22
Russian RPG 7 vs 16 inches bullet proof glass


www.youtube.com/watch?v=_J-uKNb6TaI

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RPG stands for " ruchnoy protivotankovyy granatomyot " ( Romanised ) which translates as " hand-held anti-tank grenade launcher "




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[*] posted on 24-9-2015 at 23:49


Thats a really nice video, you can see the jet penetrating and the rocket motor portion of the RPG igniting after the booster portion in the high speed footage.



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[*] posted on 25-9-2015 at 03:07


Franklyn you got me looking on the tube this one was impressive as well. nux

https://youtu.be/q6j9wEF1sf8

[Edited on 25-9-2015 by nux vomica]
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[*] posted on 25-9-2015 at 08:40
More kinematics


www.youtube.com/watch?v=7VSfUt1ggxk



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[*] posted on 25-9-2015 at 11:21


Quote: Originally posted by nux vomica  
Franklyn you got me looking on the tube this one was impressive as well. nux

https://youtu.be/q6j9wEF1sf8

i love that video, but its not a normal tandem shaped charge as the title says (afaik) , its an anti structure warhead - first one is a shapedcharge and the other detonation is a electronic delayed HE-Frag...

just sayin :D
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[*] posted on 1-10-2015 at 02:52


@ Nux: Did you spin those liners on a lathe? Brings back good memories. :)


[Edited on 1-10-2015 by nitro-genes]

Spun formed Copper Liners Nitro-genes.jpg - 170kB
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[*] posted on 1-10-2015 at 04:26


Attempted penetration of a 19mm steel plate with a new batch of plastic explosive but no good effect.
EFP was 30mm diameter 60 cm standoff and 17 g charge weight.
Only 12 mm penetration. I even placed some ballistics gel behind the plate to see effects on the other side:mad:

I think it is bad plastic because I added the PETN/acetone mix too fast to ice water whereas I usually add slowly. The fast addition resulted in still a fluffy non-granular product which didn't roll easily. This meant I used more binder/plasticizer which has affected VOD quite badly. There is a visible flame for a second during detonation that is not usually there.
I rolled 150 grams too which is a shame, maybe I can use it to attempt to catch the EFP slug in the next test as it looks like it is still forming the slug okay.


[Edited on 1-10-2015 by greenlight]

20150929_152604.jpg - 9.7MB 20150929_152622.jpg - 7.5MB

[Edited on 1-10-2015 by greenlight]

20151001_200015.jpg - 3.6MB

[Edited on 1-10-2015 by greenlight]




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[*] posted on 1-10-2015 at 05:06


Quote: Originally posted by nitro-genes  
@ Nux: Did you spin those liners on a lathe? Brings back good memories. :)


Nitro-genes I use a set of forming tools in a hydraulic press, I have tried spinning cones on a lathe but my success rate was low, its easier to press them out and have a 100% success rate.
cheers nux
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[*] posted on 1-10-2015 at 05:14


Too bad greenlight, looks a nicely formed efp though, it would have made a mess of that gel if it had made it through I'm sure, are you going to bump the charge weight up by much for the next try?.
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[*] posted on 1-10-2015 at 05:22


I think I will use 20 to 24 grams next time but I think it should have penetrated more than 12mm. The last EFP with the same specs went straight through the 10mm steel with hardly any sign of loss of velocity.
I am convinced it is the plastic explosive having too much inerts and fluffy PETN as you should be able to see the flame on camera at normal speed.




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[*] posted on 1-10-2015 at 15:44


Have you considered making the projectile like a spear? This is achieved by placing a metal cross across the back of the copper platter. There are patents which detAil his the elongated spear is made and this would probably help the penetration greatly. This is a tantalum liner and they have worked out how to catch them intact somehow

image.png - 221kB




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[*] posted on 1-10-2015 at 18:51


I know that curvature of the liner and the head height of the explosive affect the elongation of the liner. I think I am getting quite wide slugs instead of more elongated shaped because the explosive height in the charge above the liner is only .75 the diameter of the liner. This is because of the density of the PE though its rollled for several hours to about 1.45-1.49.

This metal cross idea sounds interesting. I will look for patents documenting it if it too affects the elongation of the liner it could be useful. I always thought altering the back of the liner having it thicker in parts would make it break up when subjected to a detonation wave.
The projectile in the picture you just uploaded is the perfect shape for penetration and is the most well-formed I have ever seen. I wonder how they caught it in that state:o


[Edited on 2-10-2015 by greenlight]

[Edited on 2-10-2015 by greenlight]




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[*] posted on 1-10-2015 at 20:14


Try a little more curvature greenlight it will push the efp more towards a jetting formation and will make a smaller projectile and more penetration .
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