| Pages:
1
..
19
20
21
22
23
..
68 |
enhzflep
Hazard to Others
Posts: 217
Registered: 9-4-2006
Member Is Offline
Mood: No Mood
|
|
Yes indeed Sir, I have used these very things in the past. US$50 is a VERY good price. We used to pay around Aus$80 for just a brass doming block -
never mind the punches, or the fact this one is carbon steel. For the equivalent in Aus we're looking at 300 bucks...
As for AXTs idea, I don't see why it wouldn't work. Jewellers use a very similar arrangement for reducing the size of plain wedding bands. Obviously,
rings are quite narrow or short compared to a piece of tube to be used for making cones, but the rings did indeed come out conical.
I'd be inclined to think you'd need a number of different dies, that changed angle. So you would have a slight reduction at the start of the series
and a rather pointed mandrel (as the image above) at the end of the series. My guess is that you'd get away with perhaps 5 or six punch/die pairs.
Definitely worth investigating..
|
|
|
tito-o-mac
Hazard to Others
Posts: 117
Registered: 30-6-2007
Member Is Offline
Mood: No Mood
|
|
Hey check this out. It's rather similar to a shaped charge but it's an Explosively Formed Penetrator! An explosively formed penetrator (EFP), also
known as an explosively formed projectile, a self-forging warhead, or a self-forging fragment, is a special type of shaped charge designed to
penetrate armour effectively at stand-off distances.
Here's the description: A conventional shaped charge generally has a conical metal liner that projects a hypervelocity jet of metal able to penetrate
to great depths into steel armour; however, in travel over some distance the jet breaks up along its length into particles that drift out of
alignment, greatly diminishing its effectiveness at a distance.
Whereas for the EFP, on the other hand, has a liner in the shape of a shallow dish.The force of the blast molds the copper plate into any of a number
of configurations, depending on how the plate is formed and how the explosive is detonated. Sophisticated EFP warheads have multiple detonators that
can be fired in different arrangements causing different types of waveform in the explosive, resulting in either a long-rod penetrator, an aerodynamic
slug projectile or multiple high-velocity fragments. A less sophisticated approach for changing the formation of an EFP is the use of wire-mesh in
front of the liner: with the mesh in place the liner will fragment into multiple penetrators.
As a rule of thumb, an EFP will perforate a thickness of armour equal to only about the diameter of its charge, whereas a typical shaped charge will
go through six or more diameters.
[Edited on 16-7-2007 by tito-o-mac]
|
|
|
tito-o-mac
Hazard to Others
Posts: 117
Registered: 30-6-2007
Member Is Offline
Mood: No Mood
|
|
Formation of Explosively Formed Penetrator. here's a short clip: http://www.youtube.com/watch?v=JfCCXglrJuo
[Edited on 16-7-2007 by tito-o-mac]
|
|
|
MRUD
Harmless
Posts: 10
Registered: 28-2-2007
Member Is Offline
Mood: No Mood
|
|
Hi there.
I'm allways on this kind of penetrator, i have done also some tries with them.
The very first try wasn't a success, to thin not to blown apart
Target was a 5mm thick steel plate.
The second attempt wasn't a success too.
At this time, i think, the liner was to thick.
So my next project is with this liner.
2mm thick
50mm diameter
made from copper
hope getting better results with this one.
So long, hope you understand what i wanna tell you
Greetings from Germany.
MRUD
|
|
|
tito-o-mac
Hazard to Others
Posts: 117
Registered: 30-6-2007
Member Is Offline
Mood: No Mood
|
|
Can you explain more about picture 3 from top?
Do you have any measurment of the penetration? Anyway, just wanted to ask you something: when the explosives were detonated, did the container produce
any shrapnel or stay intact? One more thing: the range from which you fire from will affect the shape of the charge, also the penetration. Too close
and immature formation of the charge will reduce the penetration!
Here's a suggestion: A less sophisticated approach for changing the formation of an EFP is the use of wire-mesh in front of the liner: with the mesh
in place the liner will fragment into multiple penetrators. Also use aluminium for greater penertration against concrete targets.
BTW remeber to show us your pics ( and if maybe a video)
Anyway all the best 
|
|
|
tito-o-mac
Hazard to Others
Posts: 117
Registered: 30-6-2007
Member Is Offline
Mood: No Mood
|
|
The charges are generally cylindrical, fabricated from commonly available metal pipe, with the forward end closed by a concave copper or steel
disk-shaped liner to create a shaped charge. Explosive is loaded behind the metal liner to fill the pipe. Upon detonation, the explosive projects the
liner to form a projectile at a velocity well over 1 km/s, depending on the design and type of explosive used. This slug is projected towards the
target at about two kilometres per second. The chief advantage of the EFP over a conventional (e.g., conical) shaped charge is its effectiveness at
very great standoffs, equal to hundreds of times the charge's diameter (perhaps a hundred meters for a practical device).
It can travel up to perhaps 1000 charge diameters (CDs) before its velocity becomes ineffective at penetrating armour due to aerodynamic drag, or
successfully hitting the target becomes a problem. The impact of a ball or slug EFP normally causes a large-diameter but relatively shallow hole, of,
at most, a couple of CDs.
Try to beat the record of 100mm penetration MRUD!!
[Edited on 19-7-2007 by tito-o-mac]
[Edited on 19-7-2007 by tito-o-mac]
|
|
|
MRUD
Harmless
Posts: 10
Registered: 28-2-2007
Member Is Offline
Mood: No Mood
|
|
Hi tito-o-mac.
At first, picture 3 schows the result of the first EFP i have build.
The liner in my first was made from zinc 0.8mm thick and i knew that this liner would never build any kind of projectile. Was only for testing, what
would happen, with the liner. Means, is the impakt at the target far strewn or focused at the aimed point of impakt. So i can improve the following
liners.
Charge was about 45g PETN.
Diameter of liner ~ 5cm
Distance around 10cm
As you can see, the liner wasn't intact at time of impact.
And second, i don't think i'm able to penetrate more than 2cm coused by the quantity of PETN i normaly use.
But 100mm is a fucking nice thick steel plate, who had done these? or is this a millitary build EFP?
Greetings
MRUD
|
|
|
tito-o-mac
Hazard to Others
Posts: 117
Registered: 30-6-2007
Member Is Offline
Mood: No Mood
|
|
Sorry, I was referring to a military build EFP. Remember the very first post the gut used ANNMSA ( I don't know whats that) but I think a Ammonium
Nitrate NitroMethane Alumnium (ANNMAL) should also work, cos' its more readily available to obtain and if you do not want to use your PETN
Errr... I'm not too sure about the distance of 10cm. It seems a bit short to me though! One more thing: is the 2 cm liner thick enough to not
disintegrate with the force of the explosion? Maybe a thicker liner would work.
Very good job anyway! 
Greetings and all the best for the next project!
[Edited on 20-7-2007 by tito-o-mac]
|
|
|
MRUD
Harmless
Posts: 10
Registered: 28-2-2007
Member Is Offline
Mood: No Mood
|
|
All my charges based on try and error, the only reference i have are some patents and some suggestions from the internet.
So i hope the third liner will do a better job as the 2 before.
The first one disintegrated (he was to thin), the second one didn't, but he was to thick to form up an projectile (4mm of thickness, you can see, the
hole in the plate is the same diameter as the liner had)
So i decided to try a copper liner between this thickness.
I give him a try. Also i can increase the distant couse this liner is formed more precisely as the 2 before, think, 20cm will worke to hit such a
small target.
Hope to get the time to set up the charge of next weekend.
Then we can discuss the result.
Greetings
MRUD
[Bearbeitet am 22-7-2007 von MRUD]
|
|
|
tito-o-mac
Hazard to Others
Posts: 117
Registered: 30-6-2007
Member Is Offline
Mood: No Mood
|
|
Did you know there is a way to control the shape of the EFP? All u need to do is stick a tube with the desired shape you want at the centre of the
copper plate, and it will mould in to the shape.
So far, got any more pics to show us on your progress?
[Edited on 23-7-2007 by tito-o-mac]
Attachment: Segmented kinetic energy explosively formed penetrator assembly - US Patent 6510797.mht (80kB)
This file has been downloaded 1589 times
|
|
|
MRUD
Harmless
Posts: 10
Registered: 28-2-2007
Member Is Offline
Mood: No Mood
|
|
Here we go, EFP mark III.
I think, it's an nice result i got. Not the best, but better than expected
Target was a 5mm thick steel plate, distance to target around 40cm.
Got a nice hole in the plate, and the force was strong enougt to deform the 2cm plate behind.
At the target site
result
Greetings
MRUD
|
|
|
E-tech
Harmless
Posts: 36
Registered: 30-5-2007
Member Is Offline
Mood: No Mood
|
|
Very well done, MRUD!
A few questions- how are you forming the copper? What is the final weight of the copper (before detonation, of course), and, what angle is the copper
cone (again, before detonation)?
|
|
|
MRUD
Harmless
Posts: 10
Registered: 28-2-2007
Member Is Offline
Mood: No Mood
|
|
The copper plate was formed with a "matritze" (don't know the english word) a picture will show you, what i mean. He was pressed between this to.
Liner weight was 37g, angle around 30°
And i (wasted) used 56g of PETN at this EFP.
|
|
|
UnintentionalChaos
International Hazard
Posts: 1454
Registered: 9-12-2006
Location: Mars
Member Is Offline
Mood: Nucleophilic
|
|
The word you are looking for is a "die" Very nicely done.
Department of Redundancy Department - Now with paperwork!
'In organic synthesis, we call decomposition products "crap", however this is not a IUPAC approved nomenclature.' -Nicodem
|
|
|
Marsh
Hazard to Self
Posts: 79
Registered: 28-7-2006
Member Is Offline
Mood: No Mood
|
|
Have you thought about using a small shaped cavity between the copper plate and the energetic so that Monroe forces act on the plate, to somewhat
shape it into a longer projectile? Then again, jet formation may penetrate the plate too easily.
Or, what about using a waveshaper in your energetic to form the plate to a more desireable shape?
Don't really know much about EFPs, just throwing some ideas out there.
|
|
|
kiknet
Harmless
Posts: 7
Registered: 2-5-2006
Member Is Offline
Mood: chargin
|
|
MRUD have you thought about in your next test ( if you do one ) attempting a long standoff for the EFP ( say a couple of meters? ).
Also I think it was here that someone asked why in rockets and certain military weapons that the shaped charge liner had a trumpet shape, I lost the
reference but it was a military brochure for a rocket weapon system that said the trumpet shape creates a better BHE ( Behind Armour Effect ),
basically I think that means it does more damage on the inside of the tank once it penetrates the amour.
|
|
|
franklyn
International Hazard
Posts: 3026
Registered: 30-5-2006
Location: Da Big Apple
Member Is Offline
Mood: No Mood
|
|
[Edited on 21-11-2007 by franklyn]
|
|
|
Bert
Super Administrator
Posts: 2821
Registered: 12-3-2004
Member Is Offline
Mood: " I think we are all going to die. I think that love is an illusion. We are flawed, my darling".
|
|
Downloaded ICEOWS, but I can't open the .ice file. Any suggestions?
|
|
|
HMTD
Harmless
Posts: 12
Registered: 24-10-2005
Location: MSC,RF
Member Is Offline
Mood: No Mood
|
|
Franklyn, is it kind of joke? If so, it's not funny. I spent several hours to find a program to unpack your *.ice archive. Maybe you'll share the
program you used to pack the files?
|
|
|
enhzflep
Hazard to Others
Posts: 217
Registered: 9-4-2006
Member Is Offline
Mood: No Mood
|
|
Ha, ha - nice one HMTD.
Spent several hours looking for an ACE unpacker??!
If you're serious, and you can't find an opener, try IZArc. Perhaps that will open these files - it definitely supports ACE files,
I'm just not sure if it will touch these files, in light of Bert's troubles.
Anyhoo, it's free and small.
|
|
|
HMTD
Harmless
Posts: 12
Registered: 24-10-2005
Location: MSC,RF
Member Is Offline
Mood: No Mood
|
|
enhzflep , thanks but no thanks.
Do you see the difference between *.ACE and *.ICE files? Tell me - have you downloaded the file and unpacked it with IZArc(btw,good free program)? If
so, then please tell me how,mine IZArc ignores the file even renamed to *.ACE. I'm just curious, where Franklyn got such unusual and rare(maybe
very-very old) file format? There are so many free and good formats.
|
|
|
franklyn
International Hazard
Posts: 3026
Registered: 30-5-2006
Location: Da Big Apple
Member Is Offline
Mood: No Mood
|
|
Very Sorry about that , I assumed that most full feature
compression utilities such as Winrar and freeware
such as 7z are compatible , guess not.
|
|
|
enhzflep
Hazard to Others
Posts: 217
Registered: 9-4-2006
Member Is Offline
Mood: No Mood
|
|
Well,
HMTD
(goes to get reading glasses and 1/2 eaten plate of humble pie)
Sorry about that HMTD. I'm _really_ having a dumb day today. Dunno how I misread that. sorry.
Frankyln,
Thanks for the extra info - curious bit of errata about the vunerabilities, Downloading the pdfs now. Thanks mate.
S.
|
|
|
HMTD
Harmless
Posts: 12
Registered: 24-10-2005
Location: MSC,RF
Member Is Offline
Mood: No Mood
|
|
Enhzflep
It happens.
Frankyln, thanx for interesting pictures. Those people had so much fun 40 years ago. I can only imagine how much U238, Be, Hg,Pb were dispersed in
these experiments.
[Edited on 11/23/2007 by HMTD]
|
|
|
zajcek01
Harmless
Posts: 11
Registered: 6-5-2007
Member Is Offline
Mood: No Mood
|
|
Here is my experience with a fully improvised shaped a charge.
A body was made from Actimel:
http://www.actimel.com/intl/img/actimel_varieties_visu4.jpg
It was cut right above and under that orange sticker, so I got a tube.
A 40W-E14 light bulb was cut in half and inserted in tube made from actimel. That was my liner.
A bulb looked like this :
http://www.bulbman.com/images/e14bccl101.jpg
A standoff was made from a toilet paper roll, and body was filled with ~80g cast PETN/RDX/Wax.
A detonator was made from 4g PETN/RDX and 0.5g AgN3
Here are the results:
http://shrani.si/f/1Y/jI/SW3cyoB/bw.jpg
http://shrani.si/f/1n/dL/2EXCr8ko/bw2.jpg
http://shrani.si/f/1h/9J/2Fxr6I1F/bw3.jpg
http://shrani.si/f/3A/z3/bI9kS5Y/bw4.jpg
http://shrani.si/f/o/sj/2dwSsoyy/c.jpg
http://shrani.si/f/3A/4q/42DZ790E/c2.jpg
http://shrani.si/f/3s/cP/1mtn0k7X/c3.jpg
http://shrani.si/f/2r/mi/1exyD26o/c4.jpg
PS. Sorry about the first B&W images.
|
|
|
| Pages:
1
..
19
20
21
22
23
..
68 |
![[*]](images/xpblue/default_icon.gif){kind=icon}
