Sciencemadness Discussion Board

Unconventional Shaped Charges

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greenlight - 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]

nux vomica - 18-9-2015 at 02:39

The 5 plates were scattered over a half meter it just blew it to shit.

greenlight - 18-9-2015 at 02:52

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

nux vomica - 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]

greenlight - 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?

gnitseretni - 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.

nux vomica - 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]

nux vomica - 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

Microtek - 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.

Bert - 21-9-2015 at 10:26

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

markx - 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

nux vomica - 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



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[Edited on 22-9-2015 by nux vomica]

Russian RPG 7 vs 16 inches bullet proof glass

franklyn - 24-9-2015 at 19:22

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

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

greenlight - 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.

nux vomica - 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]

More kinematics

franklyn - 25-9-2015 at 08:40

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

VladimirLem - 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

nitro-genes - 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]

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greenlight - 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]

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nux vomica - 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

nux vomica - 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?.

greenlight - 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.

NeonPulse - 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

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greenlight - 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]

nux vomica - 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 .

greenlight - 1-10-2015 at 21:25

The 30mm liners are always made with a dapping block so they always have a curvature depth of 5mm.
That sounds like a good idea though Nux I could add an extra 1mm to the depth of curvature to elongate the slug more when I get some better PE made up.

NeonPulse - 2-10-2015 at 17:36

Patent : 5365852 How to create an EFP with fins.
A thin cross shaped foil between the liner and explosives.
The patent does not tell what the foil is made of, but it says about 25% of the liners thickness.

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greenlight - 3-10-2015 at 21:30

Why do they not specify what the liner material or foil cross is made out of?:mad:

Something like this Tantalum foil maybe?

http://www.ebay.com/itm/10-gram-0-35-oz-99-98-Pure-TANTALUM-...

[Edited on 4-10-2015 by greenlight]

Fulmen - 4-10-2015 at 01:12

I would assume the material would be the same as the liner. Why shouldn't it, it has the same requirements (ductility, density etc).

nux vomica - 4-10-2015 at 04:13

I would assume the easiest way to make a cone with a cross on it would be to form the cross at the same time the cone is being formed, sort of like strikeing a coin out of copper at the mint.

greenlight - 4-10-2015 at 23:35

Here's some pics from a recent test on another successful small scale EFP on steel target.
The diameter was 14mm and this time a metal casing was used for stronger confinement.
Charge was 7.5 grams PETN/RDX/plasticizer-binder and explosive head height ended up being 2x the diameter of the liner which is the highest I have ever had.
Target was 6mm thick square of steel and standoff was 30 cm.
It has made a clean 9x9mm hole and unusually another smaller hole directly above that looks like liner breakup but has formed another round hole. Two for one deal:)

[Edited on 5-10-2015 by greenlight]

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greenlight - 16-10-2015 at 02:29

Just came back from testing a new batch of PE using the usual 30mm EFP on steel.
Target was 10mm steel again but this time a slab of remelted (not as clear as fresh stuff):mad: ballistics gel was placed behind to give a rough idea of what happens behind the target.
Charge weight was 17 g which was enough to punch a nice 19mm diameter hole and push through the ballistic gel as well,
Standoff was 60cm.

It seems that as soon as the slug hits flesh like material at a lower velocity it fragments into wide wound channels of varying size. Some of the stray copper pieces separated inside the gel so much that the width of damage by the fragments is around 100mm diameter.
After the ballistic gel was cut along the wound channel lines, it was dissolved in boiling water leaving the copper fragments which are also pictured after being recovered. A lot of copper powder was also found lining the channels in the gel which gives them a brown colour.
I will use fresh ballistics gel next time but that test is enough to confirm that it would not be good at all to be in the firing line of one of these even if your behind a steel target.

[Edited on 16-10-2015 by greenlight]

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[Edited on 16-10-2015 by greenlight]

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nux vomica - 16-10-2015 at 04:22

Nice one greenlight, your going all mythbusters on us with the balistic gell, did the main part of the efp go through the gell or did it all break up inside it.

greenlight - 16-10-2015 at 05:11

Haha, there was a small main fraction of the slug that passed straight through. The rest fragmented.

I think this is why sawdust or other low density material is going to be required to catch the slug without it breaking up in future tests.
I am also on the hunt for a target thick enough for the conical SCs Nux



[Edited on 16-10-2015 by greenlight]

Microtek - 19-10-2015 at 00:28

Why do you consider the breakup to take place on contacting the gel? I would think it more likely to occur as the slug passes through the steel.

greenlight - 19-10-2015 at 02:48

I have caught a couple of deformed slugs in a tree behind the steel target and they usually retain a lot of their weight aside from the added steel coating on them.

Most of the weight of the liner was in the gel and my explanation was that the lower velocity and the stress from passing through the steel first caused instant fragmentation upon contact with the gel.
The gel was 10 cm from the back of target.
Next time I will put the gel further back and find out if the breakup comes from the gel contact or before.

EFP

Laboratory of Liptakov - 10-11-2015 at 01:29

I appreciate the enthusiasm Greenlight. I also have my experience. Catch slug is very difficult. I grab his piece, without fragmentation, of course. I believe that the gel is too short and too dense. Before gel need any other brake. For example, 2 pillows. Or something like that. Hay or straw. Liptakov.

greenlight - 10-11-2015 at 05:13

Thanks LL, yes catching the slug undamaged is a difficult task.
I wasn't trying to catch it in the last test I just wanted to see what sort of wound channel it would make.
I am collecting sawdust at the moment to make a massive 3 metre long 1 metre wide and high soft-catch box because the EFP projectile always escapes out the side or top. I think it tumbles a lot when it loses some velocity because it always happens about half a metre into the soft recovery material.

Bert - 10-11-2015 at 07:21

That's a LOT of sawdust-

Water is more easily sourced, perhaps? Probably much easier to search for slugs, as well!

greenlight - 10-11-2015 at 07:56

I'm worried that water would cause the slug to deform or frament more hitting at that high a velocity. Maybe the front section sawdust as it is softer to slow it down and the last section water to actually catch it.

nitro-genes - 10-11-2015 at 07:57

If you have a metal detector, maybe straight up on a windless day would work, assuming the projectile follows a reasonably stable trajectory in the air What goes up...:D

[Edited on 10-11-2015 by nitro-genes]

greenlight - 10-11-2015 at 08:33

Thats not a bad idea nitro, if my next soft recovery system fails I might give that a go. Wouldn't be too bad if you used a spirit level to make sure it is aiming dead straight up.
As long as the projectile didn't form badly it should fly pretty much straight.

Laboratory of Liptakov - 10-11-2015 at 12:17

Shoot vertically into the air is a good idea. The epicenter may be buried EFP. So 50 centimeters below ground, I think the sand around the EFP. Established perpendicular to the pipe, and 1 meter long for the spirit level. No wind at night (often). Another thing. The space can be a grassy field. Meadow. The grass is laid microtene film. On average, about 8 meters bags, thus the radius of 4 meters. Microtene is rustling material. Will hear the impact. The impact liner may be expected in about 60 seconds. This is only a guess. Perhaps it is calculated. (it's all nonsense, nothing is returned...:D)
Liptakov

First conical CSC bad time

greenlight - 18-11-2015 at 02:30

Had a first attempt at a conical shaped charge courtesy of Nux vomica's cones today but with a bad end result.

Copper cone was 18 mm diameter and 42 degrees and charge casing was steel tube.
Charge was 10 grams PETN PE and was 2x cone diameter in head height.
Target was a 90mm thick steel cylinder and standoff used was 3.5x cone diameter.

There is a 15.5mm deep hole:mad: and it appears most of the copper is splattered around the area of entry not directed inside it like it should be.
I think the most likely cause is too much explosive behind the cone. I have one more cone and I think I will try 5-7 grams next time and hopefully get a better result.


[Edited on 18-11-2015 by greenlight]

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nux vomica - 18-11-2015 at 13:33

Maybe make the explosive diameter larger greenlight to help the cone jet form, I think the cone walls are thicker than the ideal size.
How far away was the detonator to the top of the cone?.

NeonPulse - 18-11-2015 at 15:33

Try also to "boat tail" the plastic and the detonation wave should hit the cone flat and greatly aid an ideal liner collapse which in turn will help penetration. It took me quite a few disappointment charges before I even got any decent penetration at all. Once you let off a few you get a feel for how to make them well. Don't be dismayed though, practice makes perfect. And even then There are the occasional failures. Nice first try.

nitro-genes - 18-11-2015 at 16:01

Shaped charges are pretty finicky, photo's look familiar. ;) In case of unsymmetrical liner splatter, it is most likely due to a prematurely disrupted jet due to either an asymmetrical liner, or non-homogenous explosive loading (air cavities). These are absolutely the most important factors determining clean jet formation. For this reason, either liquid explosives or very homogeneous plastiques (containing enough plasticiser to fill all air spaces) are best, an other option is pressing.

Wall thickness of the liner is much less important for clean jet formation. Very thick liners generally produce a well formed jet, but with lower velocity, thus penetrating less deep. Extremely thick liners, and/or driven by a relatively slow explosive can even lead to a completely "filled" jet canal, filled with liner material. In one occasion, firing a steel hemisphere (7% of CD liner thickness using an AN/NM/NC plastique left the carrot sticking out of the target plate, but no splatter at the sides was present. Should still have the picture of that somewhere. :) Very cool to see a steel carrot welded seamlessly into place into solid 5 cm steel. I contemplated it might even have some applications, similar to explosive welding. With some shaped charge explosive modelling, it may be possible to "shoot" predefined structures into very thick steelplate material, where welding might be impossible. Like sort of a nailgun on steroids, though not very practical probably in real life. :D

Supersonic liner wall jets ( from very thin liners) look like more broad homogenous splatter. Det or liner offsets produce more of 1 sided elongated penetrations, and a curved jet (picture posted by Axt in the beginning of this thread somewhere).

[Edited on 19-11-2015 by nitro-genes]

greenlight - 18-11-2015 at 21:30

@Nux, the detonator was only pushed in about 5-8mm into the charge so there was a lot of head height for the detonation wave to push through before interacting with the cone liner. I think the amount of explosive I used was still a bit too much.

@Neonpulse, Thanks, do you mean make a boat tail shape at the end where the detonator will be inserted?

@Nitro-genes, The liner was a perfectly formed cone and I packed the explosive in small quantities with a small pen around the cone so there was no air cavities. Next time I will pack it as hard as possible and then place the charge in a vice and press it to eliminate any air cavities.

The carrot sticking out of the actual entry with no spalling around the hole sounds quite interesting I would like to see that photograph.

greenlight - 20-11-2015 at 06:13

Second attempt with a conical liner shows an improvement with penetration but nothing like it should be.

This time I pressed the plastic explosive in small increments around the cone with a thin piece of metal and pressed the whole charge as hard as I could with a metal rod to make sure there were no air gaps. Charge weight was 6 grams this time and the detonator was centered just pressed about 2-3mm into the main charge.
Target was a 75mm wide piece of steel.
Result is a cleaner hole than last time but it still looks like there is a bit of spalling around it. I placed a video camera near the charge and can see what looks like a smoke ring coming out from the top right after detonation which I thought was a sign of a good shaped charge.
I can stick a small metal rod about 30mm into the cavity but I think the carrot is blocking the rest. Is there any way to cut this down the jet path more delicately than using an angle grinder to find out?


[Edited on 20-11-2015 by greenlight]

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ecos - 20-11-2015 at 11:06

@greenlight , good work.

I don't know if PETN has low detonation velocity or not but i found this link : http://onlinelibrary.wiley.com/doi/10.1002/prep.19760010504/...

I have a question : what is your primer(weight, type ,..) and how did you place it ?

All successful experiments i saw was : PETN + NG
would you be able to try this ? you won't probably need to worry about air bubbles.

[Edited on 20-11-2015 by ecos]

greenlight - 20-11-2015 at 20:07

The PE I make with the PETN should not have a low detonation velocity. I only use about 15% binder/plasticizer and end up with a product with density 1.4-1.43.
PETN at this density should have a VOD of about 7000 m/s accodring to Explosives Engineering by Cooper. Take of course a bit of velocit for the inert binders present.
It works beautifully with explosively formed penetrators, it seems conical shaped charges are a bit more touchy with the design and loading.

If by primer you mean detonator, it is a small diameter aluminum tube with 600mg pressed PETN and 200mg primary pressed on top with a small amount of ball-milled black powder on top of that to ensure ignition.

I could try the PETN/NG but the NG headaches put me off.



ecos - 21-11-2015 at 02:53

I also have headache when i deal with NG but a strong coffee should fix it.

Shaped charges need at least 6500 m/s VoD to work fine. I am sure that PETN and NG would be more than sufficient. NG will fill the air gaps and you won't need to press very hard as you did before.

Good luck and waiting for your results ;)

greenlight - 21-11-2015 at 04:27

The PETN is pushing a little over 7000m/s so that would be efficient in SC but I might stock up on the coffee and make a batch of NG if I come across any more copper cones:D

[Edited on 21-11-2015 by greenlight]

Fulmen - 21-11-2015 at 06:06

Coffee and nicotine works OK for countering the effects of NG. I helped a friend expand his basement and this required repacking dynamite into 20mm plastic tubes. After he spent an entire night listening to the pounding of his heart he left that bit to me, personally I think the rush is almost fun. But I always prepared by hitting the coffee hard, so that might be why I didn't react as much.

Personally I don't see the need for pushing the envelope when it comes to the explosives, plastic PETN is more than sufficient for SC as long as the charge is properly made. The challenge seems to be getting consistent results.

PHILOU Zrealone - 21-11-2015 at 16:17

Quote: Originally posted by greenlight  
The PETN is pushing a little over 7000m/s so that would be efficient in SC but I might stock up on the coffee and make a batch of NG if I come across any more copper cones:D


PETN is listed with a VOD of 8400 m/s confined at 1.70 g/ccm (while its max density can go as high as 1.76...so actual VOD at max density and confinement is higher than 8400 m/s --> 8700m/s.

NG has a density of 1.591 g/ccm and its VOD confined at 1.59g/ccm is 7600 m/s.

The mix of the two will be beneficial to both explosives since PETN has a negative OB (thus some fuel remains unburned and full power is not reached) while NG has a positive OB (thus some oxygen is set free without being used to burn molecular fuel).
The optimum zero OB mix should thus diplay optimal use of the inerant fuel and oxydiser and should perform better (better energy output)...but adding NG to PETN will also reduce a bit the overal density what may compete in the expression of the VOD.
--> Better use than closer density compounds like ETN or MHN with PETN.
Then zero OB mix will be no doubt the more powerful one.

[Edited on 22-11-2015 by PHILOU Zrealone]

ecos - 21-11-2015 at 18:07

MHN (Mannitol hexanitrate) is sensitive !! please avoid it
ETN would be very good solution but what about perchlorate+PETN?

pm1306 - 22-11-2015 at 11:19

Has anyone tried firing an EFP through a (plastic) container of gasoline or kerosene from a distance? The friction of the copper slug passing through the fuel at supersonic speed should generate sufficient heat to ignite it but I would be interested to know if that is true in practice.

The auto ignition temperature of gasoline is between 247 and 280 degrees according to Wikipedia. Kerosene is lower at around 210 degrees C. I would like to know the results for both.

According to Mythbusters episode 15 a standard bullet fired through gasoline does not ignite it.

According to https://en.wikipedia.org/wiki/Shaped_charge the temperature of the jet in a standard (conical) shaped charge is over 400 degrees C which in itself should be sufficient to ignite the fuel on contact.

Use of a plastic container would ensure that the ignition was not caused by the heat or possible spark caused by the slug hitting a steel container.

The distance should be sufficient to eliminate the ignition being caused by the explosion itself. (eg. 10m)

I would also be interested in the effect of firing from close range (eg. 300mm) so the explosion itself does ignite the fuel, possibly using ETN which has a positive oxygen balance. (TATP would be no good as it is endothermic.) In particular I would be interested to know whether the slug disperses the fuel sufficiently before detonation to generate a thermobaric explosion or merely a deflagration.

If possible a video of the result would be great.

(I am not into experimenting with these things myself and would prefer to leave it to those with more experience.)

ecos - 22-11-2015 at 11:43

Quote: Originally posted by pm1306  
Has anyone tried firing an EFP through a (plastic) container of gasoline or kerosene from a distance? The friction of the copper slug passing through the fuel at supersonic speed should generate sufficient heat to ignite it but I would be interested to know if that is true in practice.

The auto ignition temperature of gasoline is between 247 and 280 degrees according to Wikipedia. Kerosene is lower at around 210 degrees C. I would like to know the results for both.

According to Mythbusters episode 15 a standard bullet fired through gasoline does not ignite it.

According to https://en.wikipedia.org/wiki/Shaped_charge the temperature of the jet in a standard (conical) shaped charge is over 400 degrees C which in itself should be sufficient to ignite the fuel on contact.

Use of a plastic container would ensure that the ignition was not caused by the heat or possible spark caused by the slug hitting a steel container.

The distance should be sufficient to eliminate the ignition being caused by the explosion itself. (eg. 10m)

I would also be interested in the effect of firing from close range (eg. 300mm) so the explosion itself does ignite the fuel, possibly using ETN which has a positive oxygen balance. (TATP would be no good as it is endothermic.) In particular I would be interested to know whether the slug disperses the fuel sufficiently before detonation to generate a thermobaric explosion or merely a deflagration.

If possible a video of the result would be great.

(I am not into experimenting with these things myself and would prefer to leave it to those with more experience.)


The bullet may not ignite the fuel because the heat transfer between bullet and fuel is very small due to the high velocity of the bullet.

greenlight - 22-11-2015 at 19:38

I don't think a copper EFP liner would ignite a container of flammable liquid when it passes through.

Earlier in the thread though I mentioned an EFP liner for the Vulcan offered by Alford technologies that was magnesium and ignites as it forms. This means it can ignite flammable items behind thin steel (5mm) as the website says.

http://explosives.net/product/vulcan-magnesium-efp-set/

I have some 1mm thick magnesium sheet but it seems the liners linked are at least 2 mm thick compared to the copper ones. A 30mm Mg liner from 1mm thick sheet only weighs a little over a gram


[Edited on 23-11-2015 by greenlight]

pm1306 - 23-11-2015 at 01:15

What I am hoping is that someone can try it with a plain copper liner rather than relying on supposition. Even if the heat from the friction does not ignite it the heat generated by the huge pressure may- much like diesel ignites in a diesel engine as a result of pressure increasing the temperature. I realise that the fuel in the container is not confined like in an engine cylinder but then again the piston in a diesel engine does not move at 28,000 km/h.

Fulmen - 23-11-2015 at 02:18

Difference is you don't have a combustible mixture of fuel and air present. The impact will of course disperse the liquid, but by the time that happens the projectile will be long gone.

ecos - 23-11-2015 at 02:45

nice video for shaped charges in RPG : https://www.youtube.com/watch?v=TT2t6RbVYVU

greenlight - 23-11-2015 at 06:54

Yes, I agree, fuel will just be dispersed upon impact.

I think the only way is with a Mg liner. I have a 30mm one here that weighs 1.28 grams and is 1mm thick. I might give it a go when I have some spare explosive.

BTW, nice animation of jet formation from RPG.

pm1306 - 23-11-2015 at 13:05

Best test would probably be kerosene as it has a lower auto-ignition temperature than gasoline. If copper doesn't work then try the magnesium.

ecos - 23-11-2015 at 14:45

Quote: Originally posted by greenlight  
Yes, I agree, fuel will just be dispersed upon impact.

I think the only way is with a Mg liner. I have a 30mm one here that weighs 1.28 grams and is 1mm thick. I might give it a go when I have some spare explosive.

BTW, nice animation of jet formation from RPG.


Mg density is very low compared to copper

what is interesting in RPG that its SC is very effective with different stand-off distances because of the falling angle and it can penetrate very deep with few amount of EM.

in this video : https://www.youtube.com/watch?v=_J-uKNb6TaI you can see how strong it is !

I think there is a trick in the design of its shaped charge, what do u think ?

Bert - 23-11-2015 at 17:08

Rather than Mg, you might consider liners of either Zirconium or mischmetal. Both are denser, and pyrophoric under the conditions of interest here-

Working these materials requires a bit more care than Cu, of course!

greenlight - 23-11-2015 at 22:02

@Bert, Is it possible to buy these metals like zirconium or Mischmetal in sheet form (1mm or so thick) at a reasonable price though.

@Ecos, The Mg does have a very low density and that's why I think 2mm would be a more appropriate thickness for an EFP liner.
From the information I can find quickly because I have a lack of time, the RPG7 HEAT round has 730 grams of high explosive behind it and a diameter of 93 mm. Penetration is listed at about 500mm into hard armour.
93mm diameter is actually quite a large shaped charge.
I think the "trick's" in the RPG warhead design are:

* A perfectly made and symmetrical liner from a factory and it may be a specialized shape (tulip/trumpet).
* More powerful explosive with no air gaps (HMX and wax).
* Large charge diameter and charge weight.
* Standoff is completely dialed in.

ecos - 24-11-2015 at 01:28


I think RPG use TNT as EM and the liner doesn't look like cone , it has some bends in the side. The detonator is place in a deeper way.
have a look here and tell me what you see :


Most of the books talk about Pentolite(50% PETN and 50% TNT) as the most used EM for shaped charges.

Fulmen - 24-11-2015 at 03:58

Technically that's not an RPG but an HEAT-round, but the warheads are quite similar in design. The liner is called a trumpet liner and increases penetration at short standoffs by exaggerating the velocity gradient in the penetrator. A further improvement would be spiral flutes in the liner to counteract the rotation as this can cause premature dispersion of the penetrator.

ecos - 24-11-2015 at 05:29

Thanks for the info.
the head of the cone is not sharp angle but flat ! is this a mistake in the figures?
90mm-HEAT-T-M431.jpg - 70kB

ecos - 26-11-2015 at 02:39

@Greenlight,

I think your setup is similar to this one. I see the figure use booster(Tetryl) and it has wide area. Maybe to make the wave very flat?


sc.PNG - 74kB

greenlight - 26-11-2015 at 07:49

Yes, that looks a lot like the setup that i used. the only thing is that it has a tapered top (tamper/confinement) all the way up to the tetryl/detonator well.

It seems that the ring around the detonator is plastic or some other inert material and just functions to centre the cap. The only place where the cap contacts actual explosive is on the bottom.
I think most likely the tetryl pellet is just there to ensure that the main charge detonates and with the maximum velocity that it is capable of.

That charge has a pretty thick liner, the illustration states it is 1.9mm thick.

[Edited on 26-11-2015 by greenlight]

ecos - 1-12-2015 at 13:42

I think if you can cast PETN and ETN like this https://youtu.be/weDfp4zai3A
You would have VoD around 8240 m/s which is very powerful

It is formed by :

Quote:

The ETN was the binder.it was molten at 61℃ and combined with PETN in a plastic container and the molten mix was left to slowly cool and the cast was complete. Pretty potent for its small size.

Capture.PNG - 672kB
I think melting ETN would be very dangerous process


[Edited on 2-12-2015 by ecos]

NeonPulse - 2-12-2015 at 15:47

that looks familiar! That little puck of explosive was awesome it really struck me as to how powerful that was for such a tiny package. However mixing it in a plastic cup was not too hard but I could see problems in getting it homogeneous in a shaped charge it actually took quit a bit of work and was very nerve wracking. The idea came from a post by our good friend Mr Anonymous and can be found in the last few pages of threads under Mr Anonymous melt cast ETN PETN 2-5

ecos - 27-12-2015 at 15:39

I was watching a video for Kornet-E : https://www.youtube.com/watch?v=bPjI1YNi4uc

I noticed it has two shaped charges. The first one destroy the active armor while the second one penetrates the shield.

The first cone doesn't have enough EM over the cone head (~1.5X). I don't think this would have enough power to convert the cone to carrot shape !
1.JPG - 44kB
The second cone is large. There is some between the cone and the detonator that I don't know.any idea?
2.JPG - 35kB

Its penetration power exceed 1200mm into steel :o . This is massive power to be achieved with both cones !!!
where does this power came from ?

3.JPG - 35kB

I thought the explosion of the first cone would effect the whole system but it surprise me that the second cone is able to do its work after this explosion.
how can this happen ?


greenlight - 28-12-2015 at 01:10

I looked up the warhead explosive weight quickly and it seems the front shaped charge is 7 kg and the one behind is 10 kg so more than enough to turn the cone into a jet.
The thing between the cone and the detonator in the second picture is a wave shaper for the detonation wave and would increase the performance further.

I think the 1200mm penetration is axheivable with these amounts of explosives. Earlier in this thread I posted a photo of two 30 gram SC's with quite surprising penetration for their size.

The first explosion would detonate fractions of a second before the second and it would be such a small time difference thats it wouldn't affect the performance of the latter charge.

ecos - 28-12-2015 at 02:38

@Greenlight, I think you are mistaken

the Warhead weight is 7 kg HEAT or 10 kg not the shaped charge weight. Ref : Wiki

if the warhead is 7 kg. this will include explosive , copper cones, propellant(for 5Km) , sensors , fins, outer frame, controllers , detonator , ... etc

I believe the max weight of the first SC will be in range of 200g and the second one in range of 1 Kg.

you state the full process will take a fraction of a second between the first and second shaped charge. a fraction of a second is very large since VoD of EM are in range of 7000 m/s. in a fraction of a second many things had changed !

[Edited on 28-12-2015 by ecos]

greenlight - 28-12-2015 at 03:11

I found this also:

http://www.military-today.com/missiles/kornet_t.htm

It says total missile weight is 27 kg and warhead (explosive) weight is 7 and 10 kg.
It is quite hard to find accurate information on it.

Also, yes, I realize what I said sounded a little stupid when talking about energetic materials which detonate at thousandths of a second:)
I am unsure how the front detonation does not affect or damage the initiation system for the rear shaped charge as I just remembered a video on Youtube of a Carl Gustav warhead penetrating a brick wall with the first charge, flying through this hole and detonating the secondary charge on the other side.
I will look into it as I am interested in finding out now as well.

ecos - 28-12-2015 at 05:20

yes, it sounds interesting.

I understand from your webpage that , 27 Kg is the weight of launcher + warhead and the 7kg or 10kg are the warhead's weight.

27 kg is too much for a warhead.

I checked the penetration power of Panzerschreck. It has 700 gm of EM (60% RDX and 40% TNT) and it can penetrate 21 cm of steel.

pz306.jpg - 88kB

so it is still strange for me the superior power of Kornet-E (1200 mm ) !!!! :o



[Edited on 28-12-2015 by ecos]

Fulmen - 28-12-2015 at 05:46

Quote: Originally posted by ecos  
Panzerschreck vs Kornet-E

There are several reasons for the difference in performance. For one the Kornet is 152mm while the Panzerschreck is only 88mm. In addition there is more than 50 years between these two, modern CFD has increased our understanding of these devices significantly. Comparing these two directly is like comparing a 1940's car engine to a modern one.

[Edited on 28-12-15 by Fulmen]

ecos - 28-12-2015 at 16:19

@Fulmen, The technology of cars has changed a lot specially the design of motors and safety but the SC didn't change this much. Most of the effort was consumed in understanding how it works. I also believe most of the new changes was to improve the penetration power but most of the improvements has minor effects.

The concept in SC is EM and copper cone. most of the studies were about the suitable EM and different cones shapes or materials but the concept is the same !

Panzerschreck --> 700 g penetrates 21 cms.
Korent = ? g penetrates 120 cm

therefore , Power of Kornet-E = 5.7 power of Panzerschreck
If we assume linear equation this means the SC of Kornet should be 5.7 times the size/weight of Panzerschreck = 5.7 * 700g = 4 Kg of EM

if the warhead is 10 kg (4Kg for shaped charges , 6 kg for propallent , frame , fins, ...) this would make sense for me

Fulmen - 29-12-2015 at 00:53

I don't think you fully understand how much work has gone into SC's since it's discovery. And just look at this thread, how hard isn't to make a reliable, high-performing charge?

ecos - 29-12-2015 at 03:46

I am not expert as many here but i noticed the bad performance of the SC is due to the copper cone design and the alignment of the casing with cone and detonator.

Maybe you are right. I still have many things to learn !

greenlight - 29-12-2015 at 09:30

Also, the Panzerschrek only has one shaped charge and probably a less powerful explosive than what we have nowadays (TNT-based compared to HMX and other more powerful EM-based main charges). Another webpage I found says the Kornet missile is 27 kg and is 29 kg including launcher tube.
It is bigger, better explosive, more explosive and also has a waveshaper in the secondary charge which would increase penetration.

I have been looking at illustrations of tandem charge warheads and it seems the the first charge is always smaller than the main secondary charge. There is also always a considerable empty gap and sealed off section separating the two charges that the flight electronics is placed in on some missile designs. I can think of two ways the tandem charges are set off without damage to the second main charge:

1: Since the charges are detonated from the top and the detonation wave is propagating downward and to the sides more than back, maybe this gap stops the explosion damaging the secondary charge. If the flight electronics is placed in this gap between the two charges, that can get damaged and could act as a barrier getting destroyed before the second shaped charge gets initiated as it would no longer be needed as the missile is no longer in flight.

2: Either that or since only a fraction of a second is needed before initiating the second charge so the jet can follow the first charge's path, the explosive gases don't have time to reach the second charge and damage it before it is initiated.

ecos - 30-12-2015 at 03:20

REF : http://www.deagel.com/Surface-to-Air-Missiles/9M133FM-3_a002...
it is stated in many sites the weight of the warhead is 7 Kg and the warhead + container = 29 Kg

It would be very heavy if the warhead only is over 25 Kg !!

Of course two warheads in Kornet-E is better than one warhead and the size is also bigger so it delivers more power.

I like the first assumption, The first SC is small enough to break reactive armor and the explosion power should be controlled not to affect the second shaped charge. The second SC should should work before the first explosion affect it.

if Kornet-E use very powerful EM like HMX, the effect of the first SC (Heat, Pressure, ..) would be very hard to be controlled. This is a real challange!

Maybe both SCs are fired in the same time !

PHILOU Zrealone - 30-12-2015 at 07:09

Quote: Originally posted by ecos  
@Fulmen, The technology of cars has changed a lot specially the design of motors and safety but the SC didn't change this much. Most of the effort was consumed in understanding how it works. I also believe most of the new changes was to improve the penetration power but most of the improvements has minor effects.

The concept in SC is EM and copper cone. most of the studies were about the suitable EM and different cones shapes or materials but the concept is the same !

Panzerschreck --> 700 g penetrates 21 cms.
Korent = ? g penetrates 120 cm

therefore , Power of Kornet-E = 5.7 power of Panzerschreck
If we assume linear equation this means the SC of Kornet should be 5.7 times the size/weight of Panzerschreck = 5.7 * 700g = 4 Kg of EM

if the warhead is 10 kg (4Kg for shaped charges , 6 kg for propallent , frame , fins, ...) this would make sense for me

For a given explosive, the increase of explosion power is quadratic as a function of weight, not linear!
EP = A*(weight)²
A being a constant dependant of the geometry of the explosive charge, density of it and of the explosive itself...
This effect is obvious when plotting lead block test expansion as a function of weight of explosive for various explosives...

nitro-genes - 30-12-2015 at 08:54

What is the charge diameter of both the warheads? Weight says little, assuming that the newer launchers and warheads are likely made of super light modern composites, allowing for larger charge diameters while maintaining a portable weight. Even a precisely constructed 60 deg C copper cone, driven by a modern high VoD PBX can reach 9 CD's of penetration. Use of computer modelling and wave shapers can maintain jet tip velocities, while bringing down the weight of explosive needed, further allowing more weight effective shaped charges. Using DU or molybdenum liners can up the penetration depth to 11 or 12 CD. This would mean that the komet warhead diameter would only need to be around 100 -120 mm in diameter for 1200 mm of penetration.

For tandem shaped charges, I could imagine that even a tiny axis offfset between the two would be enough for both jets to form undisturbed.

Fulmen - 30-12-2015 at 12:33

Philou: While that is true it's not relevant to shaped charges. Beyond a certain level more explosives has little impact on the performance, so trying to calculate the charge from it's performance alone is impossible.

careysub - 30-12-2015 at 12:45

Quote: Originally posted by PHILOU Zrealone  

For a given explosive, the increase of explosion power is quadratic as a function of weight, not linear!
EP = A*(weight)²
A being a constant dependant of the geometry of the explosive charge, density of it and of the explosive itself...
This effect is obvious when plotting lead block test expansion as a function of weight of explosive for various explosives...


Assuming the stated lead block test results are as you say (I have not tried to check - I would appreciate a link if you have one), then this is true only if "explosion power" is a term defined by the lead block test results, which out of necessity only deals with small amounts of explosives.

Under such conditions non-linear effects with energy dissipation mechanisms, edge effects, detonation build-up, material yield properties, etc. are quite plausible.

With the advent of sophisticated numerical modeling techniques for explosives, and much more detailed understanding of the fundamental thermodynamic and other physical properties of explosives, it is apparent the simple lab tests like lead block expansion, sand crush, etc. are quite crude (but far from useless) at characterizing explosive performance.

But the total energy in the explosion is absolutely linear in the amount of explosive employed.

[Edited on 30-12-2015 by careysub]

nitro-genes - 30-12-2015 at 14:59

Plate dent, leadblock expansion/compression and sand crush test are somewhat crude tests indeed, all measuring different aspects of "explosive power". Lead block expansion is probably the best in estimating total energy output, but likely least effective in predicting shaped charge performance. Plate acceleration in an infinitely large absolute vacuum would come close I think, but if the plate thickness and weight would approach zero, you would probably only find the VoD. :D:D:D

[Edited on 30-12-2015 by nitro-genes]

PHILOU Zrealone - 1-1-2016 at 10:39

Quote: Originally posted by careysub  
Quote: Originally posted by PHILOU Zrealone  

For a given explosive, the increase of explosion power is quadratic as a function of weight, not linear!
EP = A*(weight)²
A being a constant dependant of the geometry of the explosive charge, density of it and of the explosive itself...
This effect is obvious when plotting lead block test expansion as a function of weight of explosive for various explosives...


Assuming the stated lead block test results are as you say (I have not tried to check - I would appreciate a link if you have one), then this is true only if "explosion power" is a term defined by the lead block test results, which out of necessity only deals with small amounts of explosives.

Under such conditions non-linear effects with energy dissipation mechanisms, edge effects, detonation build-up, material yield properties, etc. are quite plausible.

With the advent of sophisticated numerical modeling techniques for explosives, and much more detailed understanding of the fundamental thermodynamic and other physical properties of explosives, it is apparent the simple lab tests like lead block expansion, sand crush, etc. are quite crude (but far from useless) at characterizing explosive performance.

But the total energy in the explosion is absolutely linear in the amount of explosive employed.

[Edited on 30-12-2015 by careysub]

There is a graph somewhere (I can't get my hand on it) that displays the explosive power of Triazido-trinitrobenzene vs other primaries as a function of weight and resulting sand crushed...
There you see it is quadratic.

There is also that very interesting document I requested in document request and translations (9) the document was provided by Boffis and by Solo a little later.

If you plot those datas Inside excel and that you do a little maths you get this: I'm stil working on those fabulous datas!

Spherical Lead Block Test Study.jpg - 236kB

This is fabulous because:
1°)if you know this, you will be able to compare all explosives vs each other by weight but also by volume simply by knowing their parameters A and B:
LBT= A*x² + B
A is dependant of the geometry of the Lead Block Test, B is dependant of the detonator power and of sensitivity of the explosive material to initiation.
The volumic power is something that link many explosives under general rules...at first I have made assumptions by simple linear extrapolations...but this precise quadratic dependance is very interesting to get precise predictive datas.

2°)Considering the usual cylindrical Lead Block Test single point with help of those spherical LBT datas, one can convert the single point info into a precise extrapolated curve. Indeed one will easily find back A and B for the conventional cyclindrical LBT for all given explosive (Medina; TNT; RDX; Tetryl; HMX) and then for all explosives tested by the single point cylindrical LBT.

3°)The Lead block Test is biased by the use of a detonator...if the Lead Block Test was made with pure explosive D2D then the very important point 0 cm³ for 0 gr explosive(common for all explosives could be used)!
Of course the use of primaries as initial study case will be very important because they detonate from flame in minute amounts and they will give the idea on how explosive behave in large amount under self propagating detonation. Below a certain weight no detonation is observed and the quadratic dependance is not observed but at a certain weight its expansion will be exponential until it reaches the quadratic curve.

4°)I have a lot of lead at home, the spherical design allows one to use much less lead than for a cylinder...also knowing that you can play with mini-sphere is very interesting for amateur experimentalists like us...we could then provide interesting LBT datas with less lead and less explosive...
This is of course also of interest to scientist who have little explosive material under hand to test or who don't have the possibility to cast and manipulate large LBT (can be very heavy and energy consuming)!

[Edited on 1-1-2016 by PHILOU Zrealone]
Here is also a proof about the effect of the detonator...sadly I don't have its origin because it is saved image from a post of another user...
LBT-image.jpg - 96kB

[Edited on 1-1-2016 by PHILOU Zrealone]

ecos - 1-1-2016 at 15:19

@PHILOU Zrealone,
Let me help you , the last image in your post is from : Nitroglycerine and Nitroglycerine Explosives by Phokion Naoum

You can avoid the effect of detonator by adding metal oxide powder. this will avoid the low velocity detonation by increasing the speed of detonation wave inside the EM

The attached patent deal with the probs but the sensitivity will be increased for the Gelatine

Attachment: US2362617.pdf (281kB)
This file has been downloaded 366 times

Note: the link in your post is not working !


[Edited on 2-1-2016 by ecos]

nitro-genes - 1-1-2016 at 17:53

Did they correct for the amount of volume in the sphere? If the wallthickness of the sphere decreases due to a larger cavity with increasing explosive amount, then the energy is of course increasingly more efficiently transferred to aid expansion.

There probably is a large database having all these test data for a large number of known explosives. Wondered if it would be interesting to put them all in a statistical model and look at correlations and interactions between various physical properties. Most likely however, many of the test results would show strong correlations with many factors but also interactions, which would limit it's use to make ab inito predictions, even more so since the conditions of the test itself probably interact somewhat with the explosive used to determine the outcome. All explosive properties like density, VoD, energy released, volume and nature of gasses produced, etc will interact not only with each other, but also with the test itself. Even with a very large dataset and all tests performed under the most rigorously controlled conditions, there would be far to many factors to separate to come to a robust predictive model IMO.

Although not directly related to your post, similar things might happen when comparing primaries using LBT, a big confounder here would be the acceleration of the detonation wave, which is much faster for azides for example then for DDNP. It would be interesting to see whether small scale LBT for primaries like you desribe indeed would be a good predictor of "initiation potential".

[Edited on 2-1-2016 by nitro-genes]

PHILOU Zrealone - 2-1-2016 at 10:41

Quote: Originally posted by ecos  
@PHILOU Zrealone,
Let me help you , the last image in your post is from : Nitroglycerine and Nitroglycerine Explosives by Phokion Naoum

You can avoid the effect of detonator by adding metal oxide powder. this will avoid the low velocity detonation by increasing the speed of detonation wave inside the EM

The attached patent deal with the probs but the sensitivity will be increased for the Gelatine

Note: the link in your post is not working !


Thank you for the picture lost reference.

Interesting effect of Metal oxydes and Metals indeed!
This effect, if real, should be visible with the Lead block test...since a higher VOD will display more deformation energy.

My link does works for me with "Internet Explorer" and with "Google Chrome" navigators...
Anyway, you could do a fast search with the search tool of the forum into the reference folder 9 under poster PHILOU Zrealone with key word Lead Block Test ;)

PHILOU Zrealone - 2-1-2016 at 10:45

Quote: Originally posted by nitro-genes  
Did they correct for the amount of volume in the sphere? If the wallthickness of the sphere decreases due to a larger cavity with increasing explosive amount, then the energy is of course increasingly more efficiently transferred to aid expansion.

There probably is a large database having all these test data for a large number of known explosives. Wondered if it would be interesting to put them all in a statistical model and look at correlations and interactions between various physical properties. Most likely however, many of the test results would show strong correlations with many factors but also interactions, which would limit it's use to make ab inito predictions, even more so since the conditions of the test itself probably interact somewhat with the explosive used to determine the outcome. All explosive properties like density, VoD, energy released, volume and nature of gasses produced, etc will interact not only with each other, but also with the test itself. Even with a very large dataset and all tests performed under the most rigorously controlled conditions, there would be far to many factors to separate to come to a robust predictive model IMO.

Although not directly related to your post, similar things might happen when comparing primaries using LBT, a big confounder here would be the acceleration of the detonation wave, which is much faster for azides for example then for DDNP. It would be interesting to see whether small scale LBT for primaries like you desribe indeed would be a good predictor of "initiation potential".

[Edited on 2-1-2016 by nitro-genes]

Very interesting point of view and debate :D

Have you downloaded the document from my link?
It is wel expressed...the dimensions of the sphrere LBT are identical to classical cylindrical LBT, except it is spherical...so the inner cylinder to place the charge is 100% identical.

The sphere is inscriptible inside the cylinder...so both display the same diameter.
From what I have seen the difference in LBT expansion is almost the same.

[Edited on 2-1-2016 by PHILOU Zrealone]

ecos - 2-1-2016 at 17:08

Quote: Originally posted by PHILOU Zrealone  


Interesting effect of Metal oxydes and Metals indeed!
This effect, if real, should be visible with the Lead block test...since a higher VOD will display more deformation energy.


as i understand, the LBT doesn't take into consideration the effect of the detonator. With different cap number we should have different Trauzl number. I think this effect is for nitric esters only.

From Wiki , NG has higher Trauzl number than HMX, while HMX has higher VoD than NG !however the most important thing in SC is the VoD. The higher is the better.

I didn't get your point of mentioning the LBT in this thread. I am really sorry if i got lost.

I am also interested about this effect of adding metal oxides to accelerate the detonation wave inside EM. do you know any analytical way to calculate it ? I don't think the patent is mistaken .



[Edited on 3-1-2016 by ecos]

[Edited on 3-1-2016 by ecos]

nitro-genes - 4-1-2016 at 17:07

Hi Philou,

The link didn't seem to work here too, found It by using the search engine like you suggested. I was merely guessing about the cause of the observed non-linearity in the graph you posted. Pretty clever using a spherical block to prevent cracking.

[Edited on 5-1-2016 by nitro-genes]

PHILOU Zrealone - 5-1-2016 at 09:16

Quote: Originally posted by nitro-genes  
Hi Philou,

The link didn't seem to work here too, found It by using the search engine like you suggested. I was merely guessing about the cause of the observed non-linearity in the graph you posted. Pretty clever using a spherical block to prevent cracking.

[Edited on 5-1-2016 by nitro-genes]

Because there seems to be troubles...here is the direct download link fully written http://www.sciencemadness.org/talk/files.php?pid=401766&aid=39137

[Edited on 5-1-2016 by PHILOU Zrealone]

PHILOU Zrealone - 5-1-2016 at 09:23

Quote: Originally posted by ecos  
Quote: Originally posted by PHILOU Zrealone  


Interesting effect of Metal oxydes and Metals indeed!
This effect, if real, should be visible with the Lead block test...since a higher VOD will display more deformation energy.


as i understand, the LBT doesn't take into consideration the effect of the detonator. With different cap number we should have different Trauzl number. I think this effect is for nitric esters only.

From Wiki , NG has higher Trauzl number than HMX, while HMX has higher VoD than NG !however the most important thing in SC is the VoD. The higher is the better.

I didn't get your point of mentioning the LBT in this thread. I am really sorry if i got lost.

I am also interested about this effect of adding metal oxides to accelerate the detonation wave inside EM. do you know any analytical way to calculate it ? I don't think the patent is mistaken .

You wrote:
"If we assume linear equation this means the SC of Kornet should be 5.7 times the size/weight of Panzerschreck = 5.7 * 700g = 4 Kg of EM"
I expressed that the dependance is not linear but quadratic...and that's why I went to LBT...

LBT is a mix of many parameters, heat of explosion, volume of gases, VOD, pressure...it is correlated to p*V=n*R*T equation and reflects thus the total work p*V (energy output).

I'll open a specific tread about LBT ;)

Fulmen - 5-1-2016 at 10:01

Quote: Originally posted by PHILOU Zrealone  
I expressed that the dependance is not linear but quadratic.

And you'd be wrong. It's closer to an exponential curve, above a certain value you gain nothing from increasing the charge.

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