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grndpndr
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I would hazard a guess that the complexities of all SCs are such there all a technical problem and if Im not mistaken this is what makes all SCs
conical,linear,EFPs so fascinating to the majority.Witness the length of this thread as compared to most others.
I have a practical interest in CSCs and EFPs having spent a good amount of time with the 82nd abn in a combat support unit.The battalions heavy
weapons company as an antitank gunner on a tow missile system.As well as ABN Inf in panama.So what interested me first about SCs was the incredible
coherency of the jets produced from early 70s devices by trial and error w/o benefit of todays tech.30 years prior to that they still exceeded the
best were able to improvise.Thats a challenge difficult to ignore.
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DNA
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You also need to look into what you want to achieve, in a very hard material it is hard to drill a hole so you can easily blow a deep hole in there
with a shaped charge.
If you need to cut something then you can saw it or use a blow torch but if that takes too long a linear shaped charge will help.
It just depends on what you're doing, in my view conically shaped charges make deeper holes then linear shaped charges do with the same amount of HE.
The LSC just need a lot more HE because the force is devided over the whole length of your SC, while in a CSC all the force is directed into one
little point.
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grndpndr
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Ive had no luck with copper cone construction either.But it seems AXTs experince with glass funnels with a thickness of 1mm and seemingly more precise
construction than cheap martini glasses would have to be a bit more successful.On the other hand the thickness of the less dense glass would seem to
indicate athicker liner is needed to compensate for denser copper.
If size werent a consideration imp steel EFPs offer the most bang per buck if internal damage is a criteria.with 1/2lb he/platter @6100 plus /minus
mps AN/NM HE the results of an imp efp from a garge junk pile and equipment are frightening.
Other than linear charges for demolition.perforation of oil field casings and explosive welding i cant think of any commercial applications where HEs
are precise enough.
All extremely important in thier own right but i think w/o the most recent, explosive welding of dissimilar steels there wouldnt be composite armor
for tanks capable of resisting atgms and energetic warheads.Actually a nazi idea some 60 years old and intended for the same application improved
armor through the use of armor with dissimilar propertys similar to casehardened armor but on a grand scale.Impenetrable panther tanks?
[Edited on 19-2-2009 by grndpndr]
[Edited on 19-2-2009 by grndpndr]
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gnitseretni
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Made a LSC but didn't work as well as I'd hoped. It was made from copper sheet that was I believe only .025" thick, so not thick. May be that was the
reason? Used 50g PETN. (amount in pic was 100g. Mixed 87g PETN with 13% vaseline)
Pics:
http://img207.imageshack.us/img207/7926/im000622ef2.jpg
http://img13.imageshack.us/img13/9430/im000623op2.jpg
http://img145.imageshack.us/img145/1483/picture002yw6.jpg
http://img13.imageshack.us/img13/9649/picture004rv8.jpg
The LSC was made by pretty much wrapping the copper sheet around two 1/8" thick 3/4" angle iron pieces on top of each other. The edges overlapped at
the top and glued together with 5min epoxy, so not a strong bond. Could that, in addition to the thin liner, have been why the charge performed so
poorly? It's hard to see but penetration was at most 1/4" deep. And that was at the top; I placed the charge in such a way that the charge was leaning
against the target at the bottom with standoff gradually increasing towards the top where the standoff was about an inch.
Any thoughts?
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grndpndr
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Im not understanding your constructionn method.look at AXTs linear SC on page 1 should give a good idea of proper construction.The idea of varying the
standoff to help optimize standoff distances with one charge is clever.
still looking for the optimum diameter/radius of an EFP.Almost like state secrets although the cost of a proper steel or copper EFP would be
prohibitive at least for me. But for the sake of knowledge it would be interesting, though not absolutely nescessary for an effective device unless
size is an important consideration.
Has anyone else heard that the addittion of a thick steel mesh in front of a single dish efp will produce many smaller
efps to deal with multiple armored targets.Though factory made multiple efps have seperate lenses incorporated to accomplish the same more
efficiently in arty delivered top attack submunitions
I dont know the reliability of this claim but ive heard of manhole covers being converted to efp like devices!
[Edited on 19-2-2009 by grndpndr]
[Edited on 19-2-2009 by grndpndr]
[Edited on 19-2-2009 by grndpndr]
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octogen
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It seems by increasing the liner thickness, and charge length, which have been used in some powerful AT mine
like ATM-7,some magnificent result can be achieved.this design capable of projecting a EFP that can penetrate 70 millimeters of armour at 80 meters
range, producing a hole approximately 120 millimeters in diameter. It uses heavy copper disc with apex approximately of 120 degree, and 9 kg of
composition B.
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octogen
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| Quote: | Originally posted by octogen
It seems by increasing the liner thickness, and charge length, which have been used in some powerful AT mine
like ATM-7,some magnificent result can be achieved.this design capable of projecting a EFP that can penetrate 70 millimeters of armour at 80 meters
range, producing a hole approximately 120 millimeters in diameter. It uses heavy copper disc with apex approximately of 120 degree, and 9 kg of
composition B. |
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grndpndr
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| Quote: | Originally posted by DNA
You also need to look into what you want to achieve, in a very hard material it is hard to drill a hole so you can easily blow a deep hole in there
with a shaped charge.
If you need to cut something then you can saw it or use a blow torch but if that takes too long a linear shaped charge will help.
It just depends on what you're doing, in my view conically shaped charges make deeper holes then linear shaped charges do with the same amount of HE.
The LSC just need a lot more HE because the force is devided over the whole length of your SC, while in a CSC all the force is directed into one
little point. |
I agree with the above as in th instance of the large 40lb
military engineer shaped charges.Often used to make the initial hole later widened with perhaps a dozen lenghths of mil strenght det cord widening the
hole enough for the 40lb
an/al etc (nitramon) cratering charges.other methods can be used but speed dictates as well as availability of equipment.
LSCs for mil/civilian demolition are nearly indespensable.
Other SCs we havent mentioned yet still fall into the category of a SC such as saddle charges,diamond charges,used mainly to cut large diameter steel
shafts. Possibly other demolition methods, line charge/pressure charges,Breaching,cratering and ditching may fall into a SC or perhaps a demolition
method or both.The last 3 mentioned could be called purely demolition methods but the sadlle and diamond charges are surely SCs?
The LSC and the quick and dirty line charge accomplish the same end but I expect the advantage of economy of HE/ ease of placement(no tamping) going
to the LSC.However practical experience has shown me at least a tamped line charge with a moderate HE (AN/NM
70/30) provided more than ample brisance to cleanly cut 5/8 mild steel using just a bicible inner tube 1.25 dia. IIRC lightly pressed w/#6 cap.I could
crudely extrapolate the amount of HE but exact amounts Im afraid I kept no notes from a very old experience but Im quite sure the amount didnt exceed
6 to 8 oz for an 8 x5/8 plate.Is that then a shaped charge even though its not nearly as precise as the LSC?
My apologys, I dont have a method to illustrate theses various charges particularly interesting the saddle and diamond, possibly line charges as SCs.
(FM 5/25 Explosives and Demolitions)
[Edited on 6-3-2009 by grndpndr]
[Edited on 6-3-2009 by grndpndr]
[Edited on 6-3-2009 by grndpndr]
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grndpndr
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As fascinating as saddle charges diamond charges etc are
The notion that laminated glass may be the key to defeating copper platter efps
is at least eaqually fascinating (to me anyway)The idea that layers of laminated glass may destabilize the EFP redirecting its KE along the glass
laminations.Since Im in no way qualified to explain the phenomena ill direct you to the site \i discovered the info at.
Article title, "New Defense against explosively formed Penetrators" (EFPs)?
search the site "Defense Review"
Sorry I cannot provide a direct link.
The more I look at Octogens EFP the more I see a cone shaped charge? with a very shallow cone angle of 120 deg,
Is it a type of combination of the 2devices?The relatively shallow penetration with a large hole are ideal for a shaped charge intended for demolition
work particularly that of quickly making a hole for a cratering charge effectually hampering access to bridges damaging rumways etc.
[Edited on 17-3-2009 by grndpndr]
[Edited on 17-3-2009 by grndpndr]
[Edited on 17-3-2009 by grndpndr]
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octogen
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I have uploaded, very intresting manual, which is about general rules of design of sc. its old but
useful.link:http://rapidshare.com/files/209561357/manual_of_sc.pdf.html
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octogen
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Is it possible to use no metal liner in sc? the answer is yes.and the result is not actually very bad,just you will get shallower and wider hole.take
look at:http://www.havoc.com.au/linear_charge.html.
intresting, isnt it?
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octogen
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It seems the website,has been broken.http://rapidshare.com/files/210721707/point_focal_charge.html
[Edited on 18-3-2009 by octogen]
[Edited on 18-3-2009 by octogen]
[Edited on 18-3-2009 by octogen]
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grndpndr
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From the information Ive gotten thats how the Monroe effect was discovered blocks of nitrocellulose incised with US navy were detonated on steel
plates leaving a perfect impression of the impression in the HE.In an emergency its accepatable to simply carve a cone in a block of C4 as some
penetration will result.Sometimes its preferable to make a wider shallower hole such as a pipeline engine block etc.From what I was told the cylinder
charhge is the one to use for those purposes however the very large efp/slight ly conical charge you posted made a very wide hole as \i suspect not to
primarilypenetrate armor but for demolition prep.Quickly make holes for cratering charges.Octogen Id still likt to know the source you posted the sc
from!?
[Edited on 18-3-2009 by grndpndr]
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gnitseretni
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The link has a dot after the html. Just click on the link and get rid of the dot and hit your refresh button and the page should come up.
Btw, those LSC casings look just like the ones i tried to make.
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octogen
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I have the sc manual from www.dtic.mil
[Edited on 19-3-2009 by octogen]
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octogen
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Just look at another sample: MIACAH F1 mine is powerful and contains 6 kg of HEXOLITE. see how wide and thick liner is;this is certainly EFP rather
than SC. source is http://ordatamines.maic.jmu.edu/.
[Edited on 19-3-2009 by octogen]
[Edited on 19-3-2009 by octogen]
[Edited on 19-3-2009 by octogen]
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grndpndr
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Thanks for the image and the link.What little I know of efps is that the platters(i thought) are always conical even multiple efps by thier
description would seem to be conical or a geodesic like construction as thier desribed with individual 'lens' being formed into penetrators or
sometimes imp multiple penetrators having a heavy steel meshover the platter producing the individual penetrators?I wish i could recall the source but
Ill surely run across the same method(s)
if I search enough sources/patents
The liner yor referring to is obviously not made for any CSC Im aware of but that leaves alot of ground to cover as complex as some SCs have become
.
Thanks ,
again,regards
Looks like some sort of adjustable aiming mechanism atached to the efp with a possible fold down site on top?
[Edited on 19-3-2009 by grndpndr]
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octogen
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EFP Liners also can be hemispherical ,but again their depth are shallower when you compare them with hemi spherical liners for SCs. and hemispherical
liners easier to make(i think).
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497
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I'm curious, does anyone know if it would be possible to use a pyramide or tetrahedron shaped liner? If they worked, it might be quite a bit easier to
construct compared to a conical or hemispherical liner. Simply cutting triangles out of the end of a piece of heavy walled steel tube/pipe and bending
the remaining triangles of metal together. The seams could be welded, or maybe it would function with seams..
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grndpndr
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That very subject came up somewhere else iirc.Iwill look to see if I can find it again but my gut says if it were successful to any degree it would be
patented/more info published on the subject. regards.
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Deceitful_Frank
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Sounds plausible. Copper sheet could be cut in to triangles and soldered in to the shape of a baseless tetrahedron. I have never heard of this before
but I am sure some penetration could be achieved.
Just trying to visualize in my head how such a liner would plasticly deform and collapse.
It would be much easier to keep the liner geometry within acceptable tolerances than trying to form a cone or hemi by hand using copper foil or sheet.
EDIT:
Would a baseless terahedral pyramid liner produce a hole resembling a three pointed star if standoff was not judged perfectly. Obviously the more
sides the pyramid has the closer it is geometrically to a cone.
Would a twelve sided pyramid be that hard to construct and solder using 0.5mm Cu foil? ...maybe not
In theory a twelve sided pyramid is nearer to a cone than a three sided pyramid
But the three sided is structurally perfectly sound and is impossible to flex along the soldered hinges.
Our twelve sided option, or any other for that matter does not share this property. If I as to investigate this I would try it with the baseless
tetrahedron.
One downside though with this design if a cylindrical case was used would be wastage of explosive so for this reason right off the bat, efficiency is
compromised.
Quote: Originally posted by grndpndr  | | That very subject came up somewhere else iirc.Iwill look to see if I can find it again but my gut says if it were successful to any degree it would be
patented/more info published on the subject. regards. |
Not necessarily. A multifaceted liner is never going to be as efficient as a professionally spun cone or hemisphere and anyone with the money or means
and a half decent metal shop can realize this.
I think that we amateurs often have to make compromises within our hobby and we are bound to be happy taking a 5-10% loss of performance to save
ourselves a few grand of a lathe.
The big boys don't need to make these compromises so why would they even investigate a lesser technology?
[Edited on 24-3-2009 by Deceitful_Frank]
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grndpndr
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Ive seen the attemted cones by lathe turning etc Commercially likely some type of die and press are used,maybe way off base.But another idea occurred,
in HS back in the day when machine tools didnt frighten and it was acceptable for kids to use lathes etc
w/o much fear of lawsuits we had access to all types of machine tools.But what seems to me the most useful for the linear charges linear cone would be
a sheet metal brake
and shears.Not something a guy would run out and buy just for the one purpose but a machine shop particulary the one where you bought your copper
would perform the needed shearing and bends to precisely duplicate up to a 90 degree linear cone.As for the conical shaped liners the accepted name of
the machine escapes me but essentially its a large roller capable of making various angle cones or tubing looking at a tool catalog i see a sheet
metal tool called a shear,press brake, slip rolls and while I never learned to operate the roller with any proficiency the capability was there to
make a precision conical liner of various diameters from different gauge metal.
Again the tooling would cost the individual several hundred dollars for either tool but a machine shop with some specialty in sheet metal such as an
air conditioning and cooling company should have the needed tools. Im curious as to what Axts 50mm device would have been capable of if a precision
copper liner were used in place of the mod. glass funnel as well as what would occur with the linear Sc with precision formed copper liner rather than
angle AL? Likely substantial given the correct thickness copper stock as simple rolling wouldnt compromise the liner thickness unlike lathe turned
cones besides the rolled cones being much more precise and repeatable.Every machine shop a potential munitions factory.Makes me wonder the veracity of
US claims precision copper efp
'platters' were imported.Im sure given the blueprints for an effective copper platter nearly any machine shop could accomodate.The only problem I
could envision would be the raw casting with adequate material or precise enough casting obviating the need for an oversized casting.casting copper
would be no trick at all for a competent machine shop.in HS shop we often cast aluminum pieces of larger sizes than the platters seen in the
photos,copper would have been more expensive but would likely have better casting characteristics. The raw casting along with the lathe
could make repeatable platters slowly compared to punch presses but still effective.IMO
Also wanted to reiterate my sentiment that diamond charges
even saddle charges and line or tubular charges,squash head are shaped charges.Not as complex most of them excepting perhaps the diamond charge but
it seems all work on the principle of concentrating shock waves.Possibly even including pressure charges.probably impossible to include all of them as
a shaped charge in some fashion or another but
all it seems engineered placement of explosives( effectively controlled demolition) results to some degree in what we'd call a shaped charge IF the
defenition is concentrating the shock waves of the explosive?
Excuse all the edits simply additional thoughts rather than a punch press for EFPs modern precision casting could easily duplicate copper or steel EFP
penetrators en masse w/great precision-minimal hand finishing.
[Edited on 26-3-2009 by grndpndr]
[Edited on 26-3-2009 by grndpndr]
[Edited on 26-3-2009 by grndpndr]
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grndpndr
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I believe the lost wax process of casting is within the capabilitys of the garage fabricator particularly the simple shapes of the hemisperical copper
efp or the slighty angular
120 degree apex EFP platter could be roughly duplicated with a lost wax, sand cast mold at the garage or lathe equipped garage machine shop equipped
with a crude coal or gas fired forge to melt the copper.I know crude forges made with castoffs will melt through the steel leaves used in
a leaf spring suspension I was forging knives from.Far more than enough heat than needed for copper simply a hole lined with brick and a reversed
vacum connected to a steel pipe with spaced holes to allow escape of an air stream to feed 02 to the forge.Actually a large vacum is far to much! for
a small forge a hand held vacum supplied excessive oxygen to my forge heating it to very extreme almost unusable temps which had to be shut down
regularly or the steel melted with unnesscesary coal use.The sand castings are the most difficult but can be done likely with less effort than
expected and with repeatable results using the same pieces to form the wax mold.
Possibly even usable as is with some hand finishing to remove flash etc.. Just exploring some Ideas for fabrication
of various munition components. Including the very obvious copper linear cones and more difficult but very doable copper cones using common sheet
metal forming tools. In fact in lieu of the very expensive sheet metal brake a very inexpensive steel tool i believe added to the larger vise
accomplished similar results at a cost of some $9.accuracy will suffer but far better than some improvised copper linear copper cones ive seen using
angle Iron as the form and it appeared from the post allso part of the liner!? Copper sheet linear cone of sorts hammered over a piece of 1/4 in steel
angle iron with the total used as the liner .no wonder results were nil.Also as copper flashing for the roofing trade becomes more common copper stock
of varying gauges and widths are commonly available at better hardware /building centers.Good source for copper stock for these devices.
As is becoming painfully obvious w/o far better precision cones along with a HV castable or liquid ,slurry HE and precision assembly were just stuck
in a rut and our results with CSCs,LSCs,and copper EFPs just cant improve despite a better explosive etc.It seems adequate simple HEs abound.
the problem is precision manufacture of copper cones and platters along with precision assembly.Next! tantalum efps
formed from punched 'pucks' of powdered tantalum heated and pressed.Maybe much for the garage,LOL but at this point it seems baby steps to produce
even obsolescent CSCs/EFPs
tantalum.LOL
[Edited on 28-3-2009 by grndpndr]
[Edited on 28-3-2009 by grndpndr]
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octogen
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It is possible to use pyramid, i have the pdf file in this regard: http://rapidshare.com/files/218887409/pyramid.pdf.html enjoy it.
[Edited on 8-4-2009 by octogen]
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grndpndr
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Please post a pic of your hand fabricated tetrahedron liner
when its completed.Id be fascinated by the result.No disrespect but I dont think you realize the difficultys involved with fabricating a miltifaceted
liner tetrahedron or pyramid.
I think youve seriously underestimated the diifficultys in constructing what you propose.
As for the linear sc liners I saw a $38 sheet metal brake that will form the copper liner for the linear SC with great precision with up to a 90
degree angle or anything in between and is repeatable.Same cataloge featured a sheet metal roller, shears,etc for $130 for conical SC cones.I do wish
you the best but I believe the majority of SC failures are due to inconsistent,mishapen liners as well as construction.I think AXT's devices using
off the shelf materials carefully assembled proves the point.
A precision assembled pyramid or tetrahedron shaped liner may be" possible" but practical's another matter.
[Edited on 10-4-2009 by grndpndr]
[Edited on 10-4-2009 by grndpndr]
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