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nitro-genes
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I don't know what the esteemed and stumping member thinks, but I do have some thoughts...
After posting that the liner thickness probably determines the liner element velocity in a great way I was wondering what a thicker liner would do. I
decided to use a 1 mm liner, because for a 32 mm diameter charge this would be close to the recommended thickness that is 3% from charge diameter. I
had no 1 mm copper plate left, so I took 2 identical 0.5 mm thick, 60 deg. cones and spun them together on the mold until they fitted together
perfectly. They still could be seperated from eachother with ease though...
Penetration using this liner was even a little deeper than with the 0.5 mm thick liner. The entry and exit hole were considerably less wide though,
probably due to the reduced jet velocity. There was nothing strange about the entry or exit hole btw, so probably it is perfectly ok when the two
plates are completely attached...
It would be a problem I guess when there is a space between the two liners. Detonation pressure drops rapidly with increasing distance from the
explosive. So with a lot of space in between, the liner touching the explosive would be accelerated to a high speed, while the other one would not
move considerably until hit by the accelerated plate. The accelerated plate would "share" its kinetic energy with the other plate releasing a lot of
heat from the collision, reducing the perforance of the charge in a great way probably...
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Rosco Bodine
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If my mindreading skills are operating correctly
I smell a piano hinge linered linear shaped charge in the works , where the angle may be set where desired and then the pivot soldered to keep it
there .
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nitro-genes
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Lol, time to put the tinfoil back on my head again...
The idea sounds good.  I don't think the acceleration of the plates will be
affected by the fact that the two plates are connected by a hinge. Even when the two plates would be enterily seperated it shouldn't be a problem I
guess.
The force of the detonation pressure exceeds the material strenght by far, so the small amount of resistance in a liner made from one piece would be
rather insignificant...
[Edited on 2-8-2006 by nitro-genes]
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Marsh
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Well I browsed this thread a bit and have one remaining question for you guys...
Where exactly do you find copper cones from? Or what are they called specifically so that I may search for them correctly?
Thanks.
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Deceitful_Frank
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You "browsed" the best thread in the history of the internet "a bit"and now you are asking the most lazy-ass question I've heard all day!
Nigh on everything you would need to know to get up and running is contained with in the last 18 pages of this thread so I suggest you browse a bit
more...
go read and learn!
[Edited on 7-8-2006 by Deceitful_Frank]
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Marsh
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| Quote: | Originally posted by Deceitful_Frank
You "browsed" the best thread in the history of the internet "a bit"and now you are asking the most lazy-ass question I've heard all day!
Nigh on everything you would need to know to get up and running is contained with in the last 18 pages of this thread so I suggest you browse a bit
more...
go read and learn!
[Edited on 7-8-2006 by Deceitful_Frank] |
Edit: Sorry, scratch my question and stupidity...read my next post please.
[Edited on 8-8-2006 by Marsh]
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Marsh
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Alright, to make up for my question, I will impose an answer which you guys just *might like...
Try doing a search for "small cone burner", "cone burner", "brass holder" etc on Yahoo or Google.
Or, click one of these links for an idea without searching:
http://oilsandincense.com/catalog/cone_holder__brass__-__sma...
http://www.makeincense.com/cb1004.html
If brass is acceptable, I may have struck gold.
The only small problem, is that most of these have vent holes, so I advise you to try and find something without these holes on the cone (I mean the
side holes, the middle one will always be there, which isn't nesseccarily a bad thing). Although, from the looks of some of the holes, they may be of
minor effect on the jet- judging by their size and placement.
[Edited on 8-8-2006 by Marsh]
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Fulmen
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Hey Marsh, if everybody made penance like you the world would be a beautiful place. You've really given me some ideas :-)
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nitro-genes
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To be honest, I don't think they will work at all, I've tried a lot of these common item liners myself too. 
After searching for potential liners in every f*cking store in town the last couple of weeks you think you may have found what looks like the perfect
liner. So with 4 times cone diameter of penetration in mind you start building the charge...
Unfortunately, the liner is made from brass instead of copper, so 4 CD penetration goes out the window. Instead 3 CD penetration is the maximum
achievable now. Also, the liner is a little thinner than planned, so 2 CD's remain. Then you think about the explosive to use with this wonderfull
liner. 300+ kilobar explosives are difficult to realise, so you settle on PETN/Pib with 160 kilobars of detonation pressure, reducing the penetration
ability further to about half of the maximum, leaving 1 CD penetration. Of course you don't use precision made casings, but some sawed off PVC tubing
instead...
Nonetheless, happy as a kid you look at your 4 CD penetrating shaped charge, thinking about the huge amount of damage it is going to do. Finally, the
hour nears to unleashe your lethal device of death. You light the fuse, wondering if 5 cm of steel isn't too small a target for such a well made
device, and you run like hell. A HUGE explosion, and the ground surrounding the charge has become a wasteland. Seeing this you think there is no
doubt that the charge has gone completely through...
Your heart pounding with anticipation to see the hole throught the plate, you look at the plate and discover that there is nothing... nada... not even
a f*cking scratch!
WTF has gone wrong?! 
Brass may look like copper, but it has very different properties. My guess is that the presence of two or more atom sizes in an alloy reduces the
ductility and dynamic strength of the material drastically, both very important liner material properties. One possible exception to the rule that
alloys are no good is steel. I had some good result with stainless steel hemisperical coffeespoons:
--> https://secure1.getsecure.com.au/~tichum/images/p-coffeespoo...
Another thing is the wall thickness of the liner. For optimum performance the wall thickness should be around 2-5% of the liner thickness, depending
on the detonation pressure of the explosive used and the apex angle of the cone. Most of these common-item liners are between 0.2 and 0.5 mm thick at
most, since thinner plate means cheaper fabrication. I noticed that these thin walled liners produce shallow and wide penetration holes (if you can
even call it penetration) when loaded with a high velocity explosive. Probably due to supersonic or near-supersonic jet formation with little mass
involved...
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Marsh
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| Quote: | Originally posted by nitro-genes
To be honest, I don't think they will work at all, I've tried a lot of these common item liners myself too. |
Why did you have to burst my bubble so soon...why!?!?
Well that does stink. I had a good feeling that brass should perform over aluminum, and between copper and steel. I'm really not so sure that it can't
be made to do just this truthfully, without seeing so for myself.
I have one of these small incense cones at home as a matter of fact, and pent on the way. I just don't understand really, as the alloy seems quite
malleable...?
So I think I will (hopefully be able to) solder this cone to a pipe end, and test it this way.
Nitro-genes, have you just used another brass object, or have you actually used a brass cone specifically like the ones I've pointed out? Something in
me still thinks they just might work...unless some cold-hard data can talk me out of it.
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nitro-genes
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Haha, I'm so sorry... In fact I have no idea how brass would perform under ideal
circumstances. It is a known fact however that most alloys perform not very well. My guess is that it performs even worse than aluminium...
I've tried a piece of a bell and a piece of a toy trumpet as a liner with PETN/Pib, they looked like brass to me. Anyway, both liners resulted in a
large surface of the target plate covered with small dimples and craters, no jet formation whatsoever. They were not very precise too, so maybe you
have more luck...
What is the thickness and diameter of the cone you have at home, if the material is really thin, like the bell and trumpet I used, I'm pretty sure it
will not work...
Would be nice to see some results in this tread again however, so please try!
[Edited on 8-8-2006 by nitro-genes]
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Marsh
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Well, it is very thin towards the middle, maybe 0.6mm or so. But, at it's tip is is cast thicker. It may perform well until the wider portion, where
there is also holes. This is only 25mm or so diameter, a larger cone with the same similarities (which is available above) might fair quite well.
Linked is also a diagram showing the actual varying thickness areas in the cone. It looks similar to the design of a HEAT charge if you ask me.
Here are photos:
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Marsh
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I posted this in the Perchlorate compositions thread, but I feel that the info should be listed here dealing with shaped charges, so I am basically
making a double-post of it...
I was able to test AP/TCAP/MEKP in a shaped charge today, 85:7:8 ratio.
What may be useful here is to note the munroe forces demonstrated from this mixture.
The cylindrical lined charges previously tested by Axt had me interested. It appeared to me by the photos in this thread that the exits were roughly
the result of a combination of transferred munroe force/minimal (low mass) jet formation.
It just really didn't look like an efficient jet was formed by the cylindrical-lined charges. This was also mentioned, stating it may have been a
hole-punch effect.
My experiment compared to the previous in the respect that I used 16mm diameter copper tubing (vs aluminum), and that my tube length was just slightly
shorter; 57mm vs 65mm.
I felt that the minimal liner tube length I gave up (8mm) was acceptable as it helped achieve more head-height above the tube for a flatter shock
wave, and my cup container was less than optimal for mass conservation.
I felt that the L/D ratio of the tube should have still permitted a decent jet to form (if one was going to do so), so I too used zero-standoff. I
also did this to give an idea of close munroe forces generated from the AP/TCAP/MEKP mixture.
Like always, I used a plastic drink cup. The copper tube was glued to the base, and the cup was packed.
This time around, I really wanted decent head height above the liner, and a whole 465g total was used to fill the cup mostly to allow this. I could
have used much less had I used PVC pipe as the container. This is a large amount of explosive, but of coarse the amount which contributed to the jet
should have roughly been in the 270-300g range. It was again initiated by one of my weak TCAP dets.
The charge was detonated and the results achieved were not impressive of the design, although it did confirm my assumption that cylindrical-lined
charges are not effective at sufficient penetration through thick targets.
Munroe forces bent the total 2.25" of steel all the way through, but unfortunately cylindrical liners do appear to give limited jet formation, and
allowed a maximum of about 17mm actual jet penetration.
However by munroe force comparison, it is seemingly apparent that the mixture rivals ANNMSA and would be suitable for shaped charges.
On the back of the first plate, I could actually see a pinpoint (actually about 2mm) of copper which penetrated completely, only to be stopped by the
second plate. Thus it is shown jet formation was minimal and/or low mass.
I have pictured todays crater viewable against the other crater made by using a plastic cone from a few days back. I explain its design in the
perchlorate thread. What I see is interesting, the jet formation (or cavity shape) seems to play a big role in penetrated material displaced, almost
of equal value to that of the liner material chosen (but then again this may seem like a given). The plastic cone charge actually removed almost the
same mass of steel it would appear, but with not as deep a penetration.
I have no doubt that if only one plate was used, damage would have occured duplicating the 1" plate test with 16mm tube which Axt performed using the
ANNMSA.
Here are the photos:
16mm Cylindrical charge vs. Plastic cone charge crater
2.25" Bent steel
Penetration w/ carrot
Back of first 3/4" plate
[Edited on 22-8-2006 by Marsh]
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Marsh
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In addition to my post above (since I cannot edit now), I had a misunderstanding of munroe forces.
I was calling the actual close-proximity shockwave effect onto the steel the munroe effect, when in actuality this is not what munroe forces are;
rather they are result of a gas jet wave from using no liner at all with a cavity.
Still though, interesting jet penetration for a charge which seems there is a lot to be learned about for perfection.
Also for those who haven't correlated this mixture I speak of to the info discussed in the Perchlorate thread, I know Vod's in an AP (ammonium
perchlorate) mixture can reach over 7000m/s, but I assume this mixture to be between 5500-6500m/s. This is just an estimate based upon mixture and
density, no cold-hard evidence really suggests if this Vod range might be correct.
[Edited on 24-8-2006 by Marsh]
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Chris The Great
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The steel is just bent from the pressure on the detonation wave. The detonation shockwave does travel a short distance outwards from the explosive,
although it drops off very quickly. Nothing to do with gas of any sort.
The munroe effect is involves gas formed with an unlined cone hitting and penetrating metal, but will not bend and spall steel, or create the bending
you see with your steel target.
It's definately interesting to see that the penetration really is very short, as Axt thought it might be. So your test was quite useful IMO.
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Marsh
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| Quote: | Originally posted by Chris The Great
The steel is just bent from the pressure on the detonation wave. The detonation shockwave does travel a short distance outwards from the explosive,
although it drops off very quickly. Nothing to do with gas of any sort.
The munroe effect is involves gas formed with an unlined cone hitting and penetrating metal, but will not bend and spall steel, or create the bending
you see with your steel target.
It's definately interesting to see that the penetration really is very short, as Axt thought it might be. So your test was quite useful IMO.
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Exactly correct, that's why I needed to re-explain myself afterwards, my understanding was a little off.
But, I do have some very useful information to offer as far as obtaining a proper liner, besides what Nitro-genes has demonstrated on producing copper
cones from spinning. In fact I feel it is the most proper liner available that has been mentioned yet...
The funny thing is that this item is probably surrounding most of us at nearby plumbing stores.
Please checkout this link (this is a wholesaler though, not a retailer): http://www.customtee.com/ends.htm
These are spun copper endcaps for termination plumbing (which are cut before the sinks etc are installed in new homes). I called this specific
manufacturer today and found out the following info: The smaller sizes (1" diameter) will have more of a pointy cone at a lesser degree (like the
second photo on that page), while the larger 1.5-2" diameter will have a cone which looks like this:
I found local retailers by contacting a wholesaler near me on the list which is linked at the bottom of their page I provided, and then they were able
to tell me the retailers they supply to.
My local plumbing shop indeed has them, and I will be picking up 1.25" and 2" diameter sizes tomorrow. As was pointed out, for a 3% thickness of cone
diameter, and assuming 1mm walls, 1.25" should be closest to optimal.
What's excellent here is the fact that these can be cut down so that needed standoff is included attached to the cone.
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Mnky
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I think PLX is 5% of 99%HNO3 and 95%Nitromethane?
Or does 65%HNO3 work for PLX?
Do i need HMTD to explode PLX?
Sorry for my bad english
Greets from Switzerland 
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Quince
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LOL!
\"One of the surest signs of Conrad\'s genius is that women dislike his books.\" --George Orwell
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Deceitful_Frank
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| Quote: | Originally posted by Mnky
I think PLX is 5% of 99%HNO3 and 95%Nitromethane?
Or does 65%HNO3 work for PLX?
Do i need HMTD to explode PLX?
Sorry for my bad english
Greets from Switzerland |
Your bad english shouldn't necessarily be a problem so long as you are actually making an effort, not simply asking to be spoonfed and atleast posting
in an appropriate topic!
You should delete your post, do some research and return in a more appropriate thread. I have some knowledge of Picatinny liquid explosive and would
be happy to help any pyro that shows evidence of helping himself
Disregard the "village idiot" of Science Madness. Do you think he wonders what life would have been like had he received enough oxygen at birth... I
will also delete my post when it has served its purpose though as for him removing his "contribution", I wouldn't hold my breath.
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nitro-genes
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Recently I tried one of the eutectic compositions mentioned by Boomer in the "Perchlorate compositions" thread...
1 part of AN, UN, HDN and NaN were finely ground and heated together at 90 deg until it was of a runny consistancy. The heat was then removed and the
mixture was allowed to cool down to 80 deg. C. after which 20% of PETN was added. This to reduce the large failure diameter for these compositions.
Upon cooling further to about 50 deg. C. the mixture became like a thick paste, that was cool enough to be loaded into the container by hand. After
loading, the charge was put into the fridge for a couple of hours which turned the composition into a rock hard material. About 10 grams of PETN/Pib
was pressed on top of this as a booster and the whole charge was fired against the side of the same block of steel that I had been using for the other
charges.
The picture on the right shows the entry hole of the eutectic loaded SC...
Strangely, the entry hole of the eutectic looks much different compared to PETN/Pib. Much less "tidy" so to say, and without the funnel shape that
quickly narrows down to the main jet channel like with the other two charges. The channal itself doesn't look as smooth as with PETN/Pib and contains
a lot of irregular ring shapes. The density homogenity is possibly somewhat less then with other plastiques and this could be the reason for the
imperfect focus. Like with the PETN/NG charge...
The penetration however was not bad at all, certainly not for a composition containing only 20% PETN. The failure diameter of this compostion should
be >1 cm, so compared to the 2-3 mm of PETN/Pib plastique I expect that the performance could even be drastically improved for larger charges. Pour
loading and fast cooling would also be much better, since the thick past I used contain a lot of precipitated AN probably. While the brisance of these
compositions comes from the principle that he fuel and oxidizer are so intimately mixed together that it behaves as an ideal explosive. Unfortuantely,
pouring proved difficult, because as soon as the mixture touches the conductive copper liner it becomes solid, resulting the incorporation of many
voids at the base of the liner. Next time I will pour the charge, using a waterbath to heat the explosives container, and cool it down quickly...
[Edited on 9-10-2006 by nitro-genes]
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franklyn
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This is an update on what I had mentioned here before
about an Israeli EM device to detonate RPG's some
distance away from the vehicle thus protected _
http://www.sciencemadness.org/talk/viewthread.php?tid=2219&a...
Cats out of the bag now it seems, see for yourself _
http://www.youtube.com/watch?v=ARM-Alwot3I
[Edited on 29-10-2006 by franklyn]
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nitro-genes
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Amazing shit! 
Do you have any clue about how it works? Nothing is said about it in the videoclip unfortunately... (maybe top secret has got anything to do with that
)
A continuous EM forcefield strong enough to demolish a rocket would require tremendous amounts of energy, so it is probably some active defence
system. Most AP RPG's are piezo initiated so it could be that enough current is produced by the rocket passing through the magnetic field that the
initiator fires. From the video though it looks like it really hits a solid wall...
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franklyn
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| Quote: | Originally posted by nitro-genes
Most AP RPG's are piezo initiated so it could be that enough current is produced
by the rocket passing through the magnetic field that the initiator fires. |
Exactly
Piezo crytals merely laying out exposed to heating by sunlight are strained such
that by merely casting a shadow on them will in many cases produce the current
sufficient to fire the initiating detonator, providing the arming cicuit is closed.
Induction produced by the motion of the missile itself through a pulsed field
also contributes to the eddy current.
It happens that mechanical fuzing has to be precision made and requires
additional safeties that make's using a particular munition more cumbersome and
less reliable in the hectic enviornment of infantry operations. This is not a
problem for air ordnance where there is always time to prepare and rearm a
fighter. For this reason all modern anti tank munitions are electrically fuzed, it
also permits very accurate firing for optimal placement of the explosive effect.
Destroying any elctrical components makes it a dud.
I can imagine a tank echelon equipped with an advanced system of this type
could conceivably counteract any overhead attack from "smart munitions".
by having many tanks acting as a unit they are all defended much as large
bomber formations in WWII could fend off fighters with concentrated firepower.
There is a thread here on pulsed power devices _
http://www.sciencemadness.org/talk/viewthread.php?tid=6032
[Edited on 30-10-2006 by franklyn]
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a_bab
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Actually, it works by defeating the RPG with a "counterprojectile" (or rather a cloud of projectiles) and not by some kind of forcefield. The
protected area could be imagined though like a shield around the tank.
This involves high precision radars, cameras, target locking devices, etc. More to read here: http://www.defense-update.com/products/t/trophy.htm
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franklyn
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| Quote: | Originally posted by a_bab
Actually, it works by defeating the RPG with a "counterprojectile" (or rather a cloud of projectiles) and not by some kind of forcefield.
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On closer inspection of the cited video link here _
http://www.youtube.com/watch?v=ARM-Alwot3I
One can see in the first 2 intercepts some kind of fragments or projectiles
moving opposite to the missile. In this next link citing the "Trophy" system
http://www.defense-update.com/products/t/trophy.htm
Quote:
[color=darkred]" Specific details about the composition and mechanism of this explosive
interceptor device are vague. From the briefing provided by US sources,
Defense Update understands that Trophy is design to form a "beam" of
fragments, which will intercept any incoming HEAT threat, including RPG
rockets at a range of 10 – 30 meters from the protected platform. "[/color]
So this employs a shotgun approach to anti missile defense, and here I
thought this was cutting edge. Seems now it's nothing more than a small
version of the C.I.W.S. (close in weapon system) radar aimed 20mm
gattling gun placed on board naval ships to fend off anti ship missiles.
Quote:
[color=darkred]" The Threat Detection and Warning subsystem consists of several sensors,
including flat-panel radars, placed at strategic locations around the protected
vehicle, to provide full hemispherical coverage. Once an incoming threat is
detected identified and verified, the Countermeasure Assembly is opened, the
countermeasure device is positioned in the direction where it can effectively
intercept the threat. Then, it is launched automatically into a ballistic trajectory
to intercept the incoming threat at a relatively long distance. "[/color]
The description in the review cited does not however provide much insight
to how it can do what it claims here,
Quote:
[color=darkred]" The system can simultaneously engage several threats, arriving from different
directions, is effective on stationary or moving platforms, and is effective
against short and long range threats (such as RPGs and ATGM). "[/color]
While I fully concede I misidentified the mode of action of this device, it is
not however the only candidate for active protection, from the same source
there is also this item somewhat more in keeping with what I have in mind.
Quote:
[color=darkred]" defense consists of directional, laser-assisted electric pulsed effect.
The system uses UV laser which ionizes the air to enable effective
conduction of the electrical pulse to a range of up to 30 - 100 meters.
The pulse will disrupt the electronic elements of the incoming missile
and could also trigger it to explode immaturely."[/color]
http://www.defense-update.com/products/x/xads-aps.htm
[Edited on 4-11-2006 by franklyn]
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