EFP Aspect Ratio Growth

[jwduquette1]

Sort of self explanatory, but of interest regarding growth rates in EFP aspect ratio over the past 25(+) years.

 

[Vasiliy Fofanov]

Sort of self explanatory, but of interest regarding growth rates in EFP aspect ratio over the past 25(+) years.

 

Impressive! Do they actually plan to get to 1:22 by 2010?!

[jwduquette1]

Impressive! Do they actually plan to get to 1:22 by 2010?!

 

the 22:1 is 2007. as far as i know this has already been done with experimental efps. no idea regarding the liner material being employed.

[jwduquette1]

This looks more like the real deal -- long rod EFP of perhaps L/D=16 to 18 depending upon what you want to call the average diameter, and where you define the tail to be.

 

[Vasiliy Fofanov]

This sure looks wicked... I suppose this makes any prospect of protecting the roof of an MBT by sheer armor completely pointless, it's really time for the new design...

 

Are the EFP mines that US forces have so much trouble with in Iraq these days of the old circa 1:1 L/d generation?

[Guest pfcem]

Wow!

 

I knew about 10:1-15:1 EFPs but >20:1.

 

That makes active defense systems much more important in the near future.

[DB]

This looks more like the real deal -- long rod EFP of perhaps L/D=16 to 18 depending upon what you want to call the average diameter, and where you define the tail to be.

 

This image appears [in] this presentation: http://www.dtic.mil/ndia/2001armaments/fong.pdf, dated 2000.

 

It is described as a "long stretchy rod", which is suitably vague , but is in comparison with a more stubby tailed projectile described as "aerostable".

 

In other similar presentations, there appears to be a distinction between long and short stand-off EFPs, and this seems to me to be blurring the apparent distinction between EFP and "jet" type shaped charges.

 

It seems clear that almost continual improvements in design and manufacturing (plus advances in explosives technologies) continues to improve the performance and stability of shaped charges.

 

I wonder if it's conceivable that EFPs will outperform APFSDS in the frontal armour contest, eventually.

 

David

 

[Edit] in brackets

Edited February 13, 2007 by DB

[Vasiliy Fofanov]

This image appears [in] this presentation: http://www.dtic.mil/ndia/2001armaments/fong.pdf, dated 2000.

 

It is described as a "long stretchy rod", which is suitably vague , but is in comparison with a more stubby tailed projectile described as "aerostable".

 

In other similar presentations, there appears to be a distinction between long and short stand-off EFPs, and this seems to me to be blurring the apparent distinction between EFP and "jet" type shaped charges.

 

Ah, so this projectile might not maintain integrity over a sufficiently long distance to merit its use in sensor-fused munitions? This is interesting in light of the argument we had with Dave (DKTanker) recently over what should be called an EFP Indeed the line might be increasingly blurring...

[DB]

Ah, so this projectile might not maintain integrity over a sufficiently long distance to merit its use in sensor-fused munitions? This is interesting in light of the argument we had with Dave (DKTanker) recently over what should be called an EFP Indeed the line might be increasingly blurring...

That's what made me decide to post. We're only seven years late

 

Note, however, that I don't think there's enough information to discount its use in any particular application - we don't know what constitutes "long" and "short" range with respect to EFPs, and they aren't giving us any clues in the stuff I could find in a few minutes.

 

Note that the presentation also shows that significantly different cone shapes are being experimented with, that separate papers show that CL-20 (based?) explosives like LX-19 have significant effects on jet stability and tip speeds, and also EFP lengths.

 

It's interesting to see that considerable progress in shaped charge munitions is continuing, although I would say that the MEFP smiley example given may be considered by many to be in poor taste

 

David

[Guest JamesG123]

Are the EFP mines that US forces have so much trouble with in Iraq these days of the old circa 1:1 L/d generation?

Probably. The ones encountered where we were located were quite crude, though still effective enough to punch holes in M1114s.

[EchoFiveMike]

The problem as I see it with long EFP's is that the material is not strong enough to defeat active armour arrays, such as NERA or ERA. Comments? S/F....Ken M

[Guest JamesG123]

Probably not even strong enough to defeat high density/hardness materials like DU or ceramics.

[Guest bojan]

...Are the EFP mines that US forces have so much trouble with in Iraq these days of the old circa 1:1 L/d generation?

 

Yugo TMRP-6 trows 1:3 slugg.

[DKTanker]

Ah, so this projectile might not maintain integrity over a sufficiently long distance to merit its use in sensor-fused munitions? This is interesting in light of the argument we had with Dave (DKTanker) recently over what should be called an EFP Indeed the line might be increasingly blurring...

Hello? Somebody mention my name?

[DKTanker]

The problem as I see it with long EFP's is that the material is not strong enough to defeat active armour arrays, such as NERA or ERA. Comments? S/F....Ken M

Yet

[EchoFiveMike]

Well, materials ductile enough to plastically deform under explosive load into useful shapes generally rules out the strength to withstand the side shear loads of NERA and ERA. It's the reason the savages use copper, and why those generally only do well vs thin plates that they massively overmatch, projo diameter vs target thickness. A damned M1114 door is only 1/2"(ish) thick and they shear/plug like a MF due to HHS. An EFP is different than a more simple platter charge, with the EFP actually forming into aero stable slug. Vs the usual target sets(UAH's/trucks), the difference is academic, but vs real AFV's, the Iraq/Iran low tech EFP's don't do so well. S/F.....Ken M

[Vasiliy Fofanov]

I think poor performance of insurgent/terrorist/savage/whatever you want to call them weapons has more to do with a lack of fundamental understanding of the science and engineering behind said weapons rather than choice of material, etc. Sure they dont have access to the latest and greatest material science has to offer, but well designed warheads using vanilla materials should be potent enough. Are we really complaining they dont know what they are doing though?

 

Oh, I think they perfectly well know what they are doing. What I see on the picture is cheaply produced compact charges that would be very effective against the most common targets, 4-wheeled vehicles. It's what would be perfect to mass-produce for arming guerrilla units. You wouldn't want to waste tantalum for a liner, or have high-precision HE shaping process, when what you are producing is disposable weapons for disposable people.

 

[EchoFiveMike]

 

There are few if any materials that WONT deform plastically under the focused loading of high explosives. Pressure generated by explosives are orders of magnitude higher than the yield strength of pretty much any material of interest. Heck, you can make passable (functionally not militarily) shaped charges using ceramics.

 

With shaped charges you're in a regime of material behavior where classic concepts of ductility, strength, etc dont even conventionally apply.

 

I think poor performance of insurgent/terrorist/savage/whatever you want to call them weapons has more to do with a lack of fundamental understanding of the science and engineering behind said weapons rather than choice of material, etc. Sure they dont have access to the latest and greatest material science has to offer, but well designed warheads using vanilla materials should be potent enough. Are we really complaining they dont know what they are doing though?

 

I'm curious to see if anyone has done some hard research using "ductilized" DU as an EFP material. We know its meh for a HEAT round but as an aero stable slug?

 

We're not talking standoff critical shaped charges, we're talking aerostable EFP's, where standoff is largely irrelevant except as defined by velocity decay. Sure, a piece of crap material MAY pancake into a roughly conical shape when hit with explosives(but then again, it may blow into all sorts of chunks), but that's not what we're discussing.

 

The savages are using techniques and tools that are adequate for what they are trying to do, some are better than others. Vas is correct in his assessment. What works against UAH's doesn't cut it against real AFV's. That's all I'm stating. S/F....Ken M