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2 hours ago, Bronezhilet said:

It's not better at poking a hole in solid steel, but it should be way better at poking a hole in a NERA package.

 

Wouldn't that depend on how much spacing there is between the main jet and tertiary jet? If the head of the main jet were touching or nearly touching the tail of the tertiary jet, then I imagine that the bulging of the NERA when initiated by the tertiary jet could still catch the main jet. My impression is that this isn't a true triple charge design in terms of delay between the 3 charges, but that the the main and tertiary charges are used to create a single long jet by precise timing.

 

Also, something to keep in mind that having a hole in the middle of the main charge does decrease its efficiency. So perhaps a reason that this design hasn't caught on is that it's not the most mass efficient choice when designing a warhead.

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8 minutes ago, DD000 said:

 

Wouldn't that depend on how much spacing there is between the main jet and tertiary jet? If the head of the main jet were touching or nearly touching the tail of the tertiary jet, then I imagine that the bulging of the NERA when initiated by the tertiary jet could still catch the main jet. 

Correct.

9 minutes ago, DD000 said:

My impression is that this isn't a true triple charge design in terms of delay between the 3 charges, but that the the main and tertiary charges are used to create a single long jet by precise timing.

Yeah the timing these charges have basically determines 'what it is'. 

But if your goal is to create one long jet, why not have a single low angle charge? They have more than enough length to do so.

 

18 minutes ago, DD000 said:

Also, something to keep in mind that having a hole in the middle of the main charge does decrease its efficiency. So perhaps a reason that this design hasn't caught on is that it's not the most mass efficient choice when designing a warhead.

It doesn't impact the penetration depth by that much though.

 

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Well, regardless of what the triple-charge design was supposed to do, apparently it didn't work that well, as the Russians haven't pursued such a design since, to my knowledge. Nor has any other nation even attempted to adopt such a design.

 

Seems like the tandem charge is here to stay for the forseeable future.

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@Bronezhilet@DD000

 

http://proceedings.ndia.org/1590/11756.pdf

"HF IBFS is a tandem warhead system composed of an ø83mm precursor and a multipurpose ø143mm K-charge warhead. The tandem warhead system is capable of engaging and defeating heavy armor tanks, modern urban structures, light shipping vessels, and various soft targets. The ø83mm precursor is a shaped charge warhead containing a conical metallic liner and is capable of defeating the most advanced Explosive Reactive Armor (ERA) encountered on modern tanks. The ø143mm K-Charge warhead employs a variable wall thickness metallic liner and is the primary kill mechanism when engaging heavy armor tanks, light armor personnel carriers, or shipping vessels. The ø143mm K-Charge is packaged in a hardened steel body and is capable of penetrating and defeating a suite of modern urban structures and bunkers. The hardened steel body provides exceptional lethality against soft targets via high velocity fragments and overpressure impulse. The HF IBFS warhead incorporates Insensitive Munition (IM) explosive as well as an inventive, thermally activated aft closure to comply with IM standards and protect the warfighter during hazardous battlefield environments."

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52 minutes ago, Militarysta said:

1984, Leopard 2 in soviet report:

nDwNyfG.png

 

 

pvKIKoe.png

 

As we can see - Soviet assume Leopard 2 armour in 1984 on 400-450mm vs KE and 550-600mm vs HEAT

 

 

Yes but they don't say where (it's almost universal that the turret gets better armor), and they don't base their findings on anything.

 

400mm vs KE and 550-600mm vs CE seems more like well considered speculations than the results of actual tests. 

 

There're plenty other, more credible and better-sourced sources of information that provide us with a much clearer picture of the approximate armor values of the Leo 2.

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On 7/15/2018 at 11:23 PM, Militarysta said:

1984, Leopard 2 in soviet report:

nDwNyfG.png

 

 

pvKIKoe.png

 

As we can see - Soviet assume Leopard 2 armour in 1984 on 400-450mm vs KE and 550-600mm vs HEAT

 

 

What is the source?

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https://andrei-bt.livejournal.com/900675.html#cutid1

1280549_1000.jpg

 

Chieftain: 250 mm vs KE on turret and hull

Challenger 1: 500 mm vs KE on turret and at least 275 mm vs KE on hull.

Challenger 2 (1980s project): at least 500 mm vs KE on turret and hull

 

More from same source (WT forums):

1281012_original.jpg

5_fc129367f80ae126395adf420a7699ab.png

7_8c8e201c016ed7cc7ed471183925cc67.png

6_65d56835cd96fa841afed59b3836f0e4.png

 

On 6/29/2018 at 10:23 PM, DD000 said:

Very late to the party, but in the swedish document where it describes the protection estimates for the Leopard 2 improved, it assumes a single charge for the CE protection value, right? I'm curious as to how tandem charges would affect those estimates, as pretty much all serious atgm threats these days are tandem charges.

 

According to British documents on the development of Chobham armor, tandem charges provide superior penetration against it (and other types of special armor). That means the protection levels in Sweden are exaggerated against modern ATGMs.

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On 7/17/2018 at 1:54 PM, SH_MM said:

According to British documents on the development of Chobham armor, tandem charges provide superior penetration against it (and other types of special armor). That means the protection levels in Sweden are exaggerated against modern ATGMs.

 

Which british documents would those be?

 

Edit:  Also, if the Swedish CE protection estimates are exaggerated against tandem warheads, then could it also be said that their KE protection estimates are exaggerated against long rods with precursor tips like the M829A3 or those with special segmentation?

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17 hours ago, DD000 said:

 

Which british documents would those be?

 

Edit:  Also, if the Swedish CE protection estimates are exaggerated against tandem warheads, then could it also be said that their KE protection estimates are exaggerated against long rods with precursor tips like the M829A3 or those with special segmentation?

 

 

That is an interesting question.

Don't some long rods have a precursor section with a reduced diameter for poking a hole in K5 without setting it off?  That seems like it could plausibly poke a hole in NERA that lets the rest of the rod in with reduced resistance.

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18 hours ago, DD000 said:

Which british documents would those be? 

 

tdrok3K.jpg

This is a page from Assessment of foreign armour developments, dated 9th April of 1970. Re-reading the snipplet, "double acting warhead" also could imply a HEAT warhead with enough KE performance to penetrate several NERA plates before detonating, but IIRC there are also some other doucments that talk in detail about several ways of countering Burlington/Chobham armor, one of them is increasing the number of shaped charge warheads per missile.

 

18 hours ago, DD000 said:

Edit:  Also, if the Swedish CE protection estimates are exaggerated against tandem warheads, then could it also be said that their KE protection estimates are exaggerated against long rods with precursor tips like the M829A3 or those with special segmentation? 

 

My understanding is that the Swedish 120 mm APFSDS used to test the armor apparently already included a special tip to improve performance against heavy ERA. At least the APFSDS projectile has a small notch in the tip and the Swedes found that Kontakt-5 doesn't work that well against modern APFSDS anymore.

 

3k7Yr6N.png

 

In general special tip constructions and segmented penetrators can improve the armor penetration against layered and composite armor arrays. The German company Rheinmetall announced that it doesn't want to test its ammunition against RHA targets anymore, because these won't reflect the behaviour/performance of the projectiles when used against special armor arrays. Patents and certain documents, that unfortunately aren't approved for public release, also suggest that the segmented penetrators developed in Germany were optimized to defeat next-generation main battle tanks making use of ERA and layered ceramic-steel-armor (i.e. the same type of armor as used on the T-80UD prototype and on the Object 477 prototype).

 

1 hour ago, Collimatrix said:

Don't some long rods have a precursor section with a reduced diameter for poking a hole in K5 without setting it off?  That seems like it could plausibly poke a hole in NERA that lets the rest of the rod in with reduced resistance.

 

It depends on how the NERA looks. Heavy ERA and heavy NERA seem to follow different design trends, i.e. Kontakt-5 is rather thin and only single layered (sometimes two reactive insert elements are used, but they would detonate at the same time). The wedge-shaped armor of the Leopard 2 meanwhile uses multiple NERA layers with much thicker steel plates that are also claimed to be made of high-hardness steel. Therefore the interactions between penetrator and armor could be quite a bit different.

 

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7 hours ago, SH_MM said:

My understanding is that the Swedish 120 mm APFSDS used to test the armor apparently already included a special tip to improve performance against heavy ERA. At least the APFSDS projectile has a small notch in the tip and the Swedes found that Kontakt-5 doesn't work that well against modern APFSDS anymore.

 

 

I've seen the notched tip design before, such as on the charm 3, but the notched tip on the swedish 120mm apfsds seems exceptionally tiny. It seems to me like the tip would be designed to penetrate the ERA/NERA panel without setting it off, although I'm not sure how it does that exactly. If it does set it off though, then it probably doesn't do much of anything. It's easy to see how it could be completely worn away by penetrating the outer plate and front NERA plate, especially if it was a thicker NERA plate of high hardness steel. So while it does technically have a special tip, it's so tiny that I don't think it would perform much differently than a "standard" rod without any special tip in this instance, at least for the test shots on the front wedge and high obliquity shots where it would have needed to penetrated a lot of steel before getting to the NERA filler material.

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5 minutes ago, DD000 said:

 

I've seen the notched tip design before, such as on the charm 3, but the notched tip on the swedish 120mm apfsds seems exceptionally tiny. It seems to me like the tip would be designed to penetrate the ERA/NERA panel without setting it off, although I'm not sure how it does that exactly.

 

The explosives in ERA have to be quite insensitive, both so they don't get triggered by small-arms fire or artillery fragments, and also for safe handling.  If they get jabbed by a fairly small-diameter penetrator, there's a good chance they won't go off.

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11 hours ago, Collimatrix said:

 

The explosives in ERA have to be quite insensitive, both so they don't get triggered by small-arms fire or artillery fragments, and also for safe handling.  If they get jabbed by a fairly small-diameter penetrator, there's a good chance they won't go off.

But the explosives are still pressure-initiated, so wouldn't focussing all the energy of a long rod on a small diameter actually initiate an ERA earlier than a larger diameter? (Yeah I'm ignoring the fact that ERA is always angled but that doesn't change the point)

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My initial thought was that the tip was designed specifically to defeat K5, but according to the Swedish document, Kontakt-5 features an angled 17mm front cover plate. The tip looks to be about 20-25mm in length, but since the entire tip is a cone, the actual working length might be about half that. So the entire tip might be defeated by the cover plate alone. Furthermore, if a tiny thing like that stuck to the front of a long rod could defeat K5, then there would be no need for the much larger steel tip of the M829A3.

 

Its purpose is rather perplexing to me.

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On 7/20/2018 at 9:12 AM, DD000 said:

Furthermore, if a tiny thing like that stuck to the front of a long rod could defeat K5, then there would be no need for the much larger steel tip of the M829A3. 

 

As far as I know, the M829A3's tip is designed to work against more than just Kontakt-5 ERA. It is meant to also deal with other types of ERA, i.e. improved types that Russia, China and other countries could've adopted (Kontakt-5 is very old, even the Soviets worked on replacement systems).

 

The German APFSDS ammo (which is believed to have a segmented rod) is designed to defeat double-layered heavy ERA, a type of ERA that Germany believed might be fielded on future Russian tanks (but apparently they were wrong). In 2003, the US Army bought a number of T-84/T-80UD tanks from the Ukraine, maybe these were fitted with Nozh or some other ERA, which might have affected the M829A3's design.

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On 7/20/2018 at 12:33 AM, Bronezhilet said:

But the explosives are still pressure-initiated, so wouldn't focussing all the energy of a long rod on a small diameter actually initiate an ERA earlier than a larger diameter? (Yeah I'm ignoring the fact that ERA is always angled but that doesn't change the point)

 

No.  To initiate an explosive there needs to be a certain energy density in order to get a high enough percentage of the molecules within a given volume to release their energy.  Hitting the explosive with a smaller diameter rod doesn't mean that the area being impacted is being hit any harder, it just means less of it is being hit.  A reduced-diameter long rod tip isn't moving any faster than the rest of the long rod.

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2 hours ago, Collimatrix said:

 

No.  To initiate an explosive there needs to be a certain energy density in order to get a high enough percentage of the molecules within a given volume to release their energy.  Hitting the explosive with a smaller diameter rod doesn't mean that the area being impacted is being hit any harder, it just means less of it is being hit.  A reduced-diameter long rod tip isn't moving any faster than the rest of the long rod.

Doesn't it still make diameter very important? 

It's why for the same energy a bullet will pierce your skin but a truck won't even yeet you across the street.

It can't just be the sum of the energy, right?

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1 hour ago, Mighty_Zuk said:

Doesn't it still make diameter very important? 

It's why for the same energy a bullet will pierce your skin but a truck won't even yeet you across the street.

It can't just be the sum of the energy, right?

 

Small arms bullets are about half the striking velocity of long rod penetrators, different rules apply.

 

 

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1vGsblp.png

 

BTW - Im not sure DM-13. In green book (Bauman 2006 Moscow) is 220mm/60@ but IMHO it could be overestimated. From the other side - some other polish Autors found  in british archves that "unkown" german 120mm KE was able to penetrate 450mm steel from 1km in late 70's... so maybe..

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On 8/5/2018 at 5:52 PM, Militarysta said:

My resume that what we known (or not) on one picture:

 

 

Spoiler

srpB1pX.png

 

 

imho

Spoiler

3d5e98359298bb234ce212e987241e9e.png

1280549_1000.jpg

minimum protection equivalent to 275 mm RHA on the glacis and 500 mm on the turret front.

Lfkm_AawtPk.jpg

funny, but here they also talk about 500 mm vs KE

and 800 mm vs CE 

q-uQbEUz-QY.jpg

which in general coincides with the data of the British. It remains only to understand what the minimum protection means...

PS imho M1 350 mm vs KE, 400 mm vs KE M1A1

 

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Just asking, isnt the 500mm penetration of M833 is a little bit overestimated? I find it suspicious that it is more powerful than even contemporary 120mm and 125mm APFSDS. Yes, DU, and also the rod is longer, but its still a huge leap compared to M774.

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