Main Battle Tanks and Armour Technology

[methos]

From other topic:

That is false information. Paul Lakowski believed that the Leopard 2 did only have composite armour in the turret based on a statement from Jane's (excerpt from his Armor Basics: "The hull isreported to be spaced armor construction". The original Jane's statement - or at least what I think is the original statement - speaks of spaced mulit-layer armour.

If we assume that the original Leopard 2 didn't feature any composite armour at all, then contemporary sources should speak against it. But let's take a look at these:

Let's start with the oldest source I have got: "Panzer und andere Kampffahrzeuge v. 1916 b. heute" from 1977 says "At first it was believed that the Leopard 2 would use spaced armour, but in late 1976 it was revealed that the in Great Britain developed Chobham armour was used. Whereby this consists of mulitple layers of steel- and ceramic plates which alternate".
Waffen-Arsenal Band 69 from 1981 describes the armour as "high grade armour steel combination" - this doesn't speak against spaced armour, but it is also said to be "orientated at the weapon effect of potential enemy tanks [...] against armour piercing and shaped-charge rounds". However later in the same source the Leopard 2AV is shown and said to "use new technologies and to digress from the conventional type of armoured protection". It is also said that the boxy shape of the turret is the result of a new generation of armour.
Other contemporary sources like Krapke ("Leopard 2 Sein Werden und seine Leistung"; not really contemporary but Krapke played an important role during the Leopard 2 development) and Hilmes ("Kampfpanzer Entwicklungen der Nachkriegszeit" from 1984) and later Spielberger, Lobitz, Vollert etc. all write about the usage of other (non-metallic) materials in the armour.

 

[Damian]

I think that this is semantics. Composite armor can be also a type os spaced armor if there is free space (air) between at least two layers, as well as spaced armor can be a type of composite armors if it uses more than one type of material.

 

[militarysta]

I let myself to slighty improved Dejawolf 3D Leopard-2A4 modell:

misty idea about Leopard-2A0/A1 armour

A-40mm thick RHA plate
special armour (placed at 60 degree)
B1 -first NERA layer (35mm RHA whit 1630-1730MPa+ 5mm rubber + 3mm RHA)
50mm space
B -NERA (25mm RHA whit 1630-1730MPa + 5mm rubber + 3mm RHA)
35mm space
B -NERA (25mm RHA whit 1630-1730MPa + 5mm rubber + 3mm RHA)
35mm space
B -NERA (25mm RHA whit 1630-1730MPa + 5mm rubber + 3mm RHA)
35mm space
B -NERA (25mm RHA whit 1630-1730MPa + 5mm rubber + 3mm RHA)
50mm space
A2 -special armour cavity HHS backplate (50mm RHA)
and of special armour
A-RHA plate (40mm)
C -kevlar/aramid (40mm)
D -ceramis in polymer (50mm)
D -ceramis in polymer (50mm)
E - 30mm RHA backlpate no.1
E - 30mm RHA backplate no.2
E - 30mm RHA backplate no.3
Or in place "E"layers one thick RHA backplate ~80/90mm thick.

Damian can You try to recalculate this, but whit ~1980 reality? (no super-duper ceramics, just HHS and RHA). Of course without NERA layers.

 

[Damian]

@militarysta a quick and rough estimation.

Vs KE = 550-560mm
Vs CE = 618,3-628,3mm

But this is without NERA effect, as ceramics I used AD-85 wich is simple and cheap and should be avaiable in 1970-1980's. I don't know TE for kevlar.

PS. I probably made a mistake somewhere.... hmmm need to recaltulae this again but perhaps tommorow, I am tired.

 

[methos]

I think the efficiency of the NERA/bulging-plates array can easily be caluclated. According to Nii Stali bulging-plates armour can be up to 40% more effective than homogenous armour of the same weight. If I remember correctly Lidsky posted a similar value (30 to 40%?).
The array weighs as much as 152.8 mm RHA (weight equivalent to 150 mm RHA is generated by the steel part, weight equivalent to 2.8 mm RHA generated by 25 mm rubber). Thus the array should offer between 198 mm RHAe and 213 mm RHAe protection against shaped charges (152.8 mm multiplied by 1.3 - 1.4). This is not very much, maybe the slightly higher hardness of the thicker steel plates need to be taken into account...
If we use 500 to 520 HB steel plates (1,630 to 1,730 MPa) efficiency might increase to (1.3 x 135 mm + 2.8 mm + 15 mm) x 1.3 to1.4 = 251 - 270 mm RHAe vs CE.

I doubt that the three outermost steel layers are really RHA + HHS + RHA. Such a configuration would offer 40 mm + 50 x 1.34 + 40 mm = 147 mm RHAe protection
In the firing tests these three layers were however simulated by using three 100 mm thick layers of steel (softer and cheaper steel). 147 /300 means a thickness efficiency of about 0.49... this is an incredible low figure (especially sine the steel was labeled armour steel). I have seen people using figures like 0.8 for mild steel (180 HB). 300 mm x 0.7 to 0.8 (for representing mild steel) = 210 - 240 mm RHAe
Assuming we have 40 mm RHA + 50 mm HHS + 40 mm SHS (i.e. a THS layout) we can easily get 130 mm x 1.6 = 208 mm RHAe... which is much closer to 30 cm mild steel as the former layout.

I'd also assume that the polymer around the ceramics decreases tile thickness by 5 to 10 mm per layer. This would decrease TE to 0.8 - 0.9 x old TE.

I don't think that mixing armour from the early 1970s with armour from the early 1990s is going to lead to a proper result. What if the special armour cavitiy was smaller or greater on earlier tanks. What if the original tanks didn't have any kevlar in them?

FMBT76 program. In February 1974,with the consent of the British, Americans shared some knowledge of Burlinghton armor with Germnas. According to the program FMBT76 both tanks: Leopard-2 and Chieftain mk 5/2 shoud be "temporary" and came into service in midlle 1970's -and new (the target) FMBT will be ready a decade later. Ambitious plans have not been implemented, becouse Germans break out cooperations in 1976. In british oppinion it was "deliberate action" - allowing using of knowledge about "Burlington" without having to pay the cost of acquisition of technology.

I don't know much sources about the German-British cooperation during the 1970s, but the ones I have say that the British withdrew from the programme because the Germans wanted an unconventional solution (i.e. turretless or with gun in overhead mount), because they already were developing a fine conventional tank (the Leopard 2) on their own.

 

[hest]

I think the efficiency of the NERA/bulging-plates array can easily be caluclated. According to Nii Stali bulging-plates armour can be up to 40% more effective than homogenous armour of the same weight. If I remember correctly Lidsky posted a similar value (30 to 40%?).

Nii Stali gives against HEAT thickness equivalence of 1 and weight coefficient of 0.5 for whole armour structure including bulging plates (not only for "NERA element" but including base steel plates) and thickness coefficient of 1.25 and weight coefficient of 0.9 against KE, they may vary +- 0.1 depending on armour optimisation and projectile.

For example for T-72B filler of bulging plates and including atleast back steel plate HEAT protection is equivalent to thickness in steel, similar value for T-80U filler.

In fact whole space from front plate to backplate was filted by special armour. In erly German and Soviet solutions the way is diffrent. In German armour wrom overall thickens 840mm only ~500mm is "special armour". In soviet - even less (in T-80 at 0. from 740mm LOS only 340 is "special armur").
So in fact we have three different armor concepts:

1. Buringhton - all LOS is taken by "special armour" -from front plate to backplate)
2. German (at lest in 1993) - about 60% armour LOS is active woking "special armor" rest (40%) is more or less passive multilayer structure - RHA plate, HHS plate, ceramic in polymer, kevler/aramid, etc. Since 1994 this + outern NERA layers.
3. Soviet in 80's - about 45% LOS is "special armour" rest is cast steel, or RHA plate, and since ~1987 this + ERA.

Special armour were all common, structure never was only bulging plates, etc but included back plate, base armour, there is no such thing as all special armour if you refer to that. There was difference, for example base armour, steel was more predominant in Soviet structure.

So in fact protection for eacht one type of armour will be diffrent. So it's imposible to made (as You did) whole estimatous from armour model whit is not consider whit known Leopard-2 armour structure. We have 50cm special armour (it can be NERA) and after that passive layers.
Those model (scan) is (unfortunatly) not relevant in Leopard-2 thema becouse there is no sucht layout like on this model. Maybe in Leopard-2 they are two layers that look like "Glass fiber based on high modulus organic fibers) but Layotu is diffrent: HHS-RHA-kevlar/armaid-maybe glass fiber -maybe second glass fiber - RHA -RHA -RHA (or one RHA backplate 80-90mm thick) there is no layout like in this modell.

I made estimation for structure which I described, and corresponded with tank armour so it can be close to protection of first Leopard 2. Later version is different of course.

And if You want to know how good can be British Burlinghton:

And notice that for 90. degree HEAT diametr 84mm (SC) - so with perforation around 340-380mm RHA in those years - was stopped by: 203cm LOS thick erly Burlinghton module, and only ~50mm RHA (hull sides). In fact only Burlinghton module provide protction like (Carl Gustav warhed rforation - hull sides) ~290-330mm RHA.
For 30-35 degree the same module whit LOS thickens 400-450mm and hull sides thicknes 100-120mm RHA provide protection against SC (HEAT) warhed 152mm dimatere whit 600-680mm RHA perforation.
So 400-450mm LOS thick module act like ~500-560mm RHA. Of course the biggest advantage was the minimum weight of the solution.
And thsi all was in...1968.

We can go to original source

Against HEAT it was protected only for 25 degrees and which projectiles ? 127 mm and 152 mm with great cone angle of 60 degrees. Your perforation estimate is not correct because there is no such direct relation with diameter. Greater cone angle (from 25...60) implies reduction in jet maximum speed and lenghtening which results in less perforation ability, so for this case there is not any 600 mm. This armour stopped HEAT with penetration lower than thickness of the armour which is not anything special. In fact this early composite is similar to Soviet upgrade of T-55, T-62

And about later Burlinghton:

Translate:
In configuration from at the turn of 1960/1970, against SC warhed "Burlinghton" was 2-3times better then monolithic steel armour whit the same mass, and had (Burlinghton armour-milit.) similar resistance (as those monolithic steel armour ) against kinetic energy rounds.

Translate:
The mass efficiency of the new armour variants (Burlinghton -milit) increased to 1.3-1.5 agains KE and do more then 3 against SC warhed (HEAT) This part is about Burlinghton from circa 1978r.

Saying that it had such weight efficiency does not mean anything, because such efficiency had not only Burlington but it is given for many structures, and because we cannot consider the armour as a whole having in account volume and other factors. Also there was big change due to severe reduction in performance against advanced APFSDS and change in requirement. You cannot give this as absolute value. Everything within context.

 

[methos]

Nii Stali gives against HEAT thickness equivalence of 1 and weight coefficient of 0.5 for whole armour structure including bulging plates (not only for "NERA element" but including base steel plates) and thickness coefficient of 1.25 and weight coefficient of 0.9 against KE, they may vary +- 0.1 depending on armour optimisation and projectile.

In the article 'Armor with "reflective foil"' (БРОНЯ С "ОТРАЖАЮЩИМИ ЛИСТАМИ") on their website they say: "The effect of the "reflective" sheets up to 40% compared to the monolithic armor of the same mass. This type of armor used on some domestic tanks."

 

[hest]

In the article 'Armor with "reflective foil"' (БРОНЯ С "ОТРАЖАЮЩИМИ ЛИСТАМИ") on their website they say: "The effect of the "reflective" sheets up to 40% compared to the monolithic armor of the same mass. This type of armor used on some domestic tanks."

It is only extract from their publication (which I have in full). They give a table of integral coefficients of armour structures for estimations of armour protection.

 

[militarysta]

Special armour were all common, structure never was only bulging plates, etc but included back plate, base armour, there is no such thing as all special armour if you refer to that. There was difference, for example base armour, steel was more predominant in Soviet structure.

In "special armour" im mean that non passive multilayer structure placed inside tank armour LOS. In western (UK/USA) tanks it's place taken by Burlinghton armour, in German tanks it's those 500mm some armour fast-change module, and in Soviet armour we can say that "special armour" is active working filter -NERA style in T-72B and polyme cells in T-80U, behind without any doubt passive cast steel and passive RHA (HHS in fact) plate after NERA armour in T-72B and after polymer cells in T-80U.

I made estimation for structure which I described, and corresponded with tank armour so it can be close to protection of first Leopard 2. Later version is different of course.

OK, but those structue can't take more then 500mm from overal 840mm LOS. So what whit rest 340mm LOS?
And the probplem is that HEAT protection don't even stnd (in those Nii Stali materials) to M.Held works about bulging plates, or with Balistic Symhosium thesis whit 2mm RHA + rubber +2mm RHA. In both cases NERA plates offer mucht better protection then Nii Stali claimd.
Even if wy take assume by russian sources T-72B protection against HEAT ad subtract from this value cast steel (passive) protection and those 45mm thick HHS palte then still we have for 5 NERA layers protection close to (depend on angle and No. of made mesurment) :
vs HEAT ~140-210mm RHA
vs APFSDS ~250-350mm RHA (and lower)
And those values have mucht more sense in conjunction with M Held, and other Balistic Symposium research. And some NERA layout used on M.Held or BS works are very primitive and simple -like those "erly german armour" or T-72B NERA, or Hadji armour from "T-55 Enigma".
So there is something not "OK" whit Nii Stali values -they are understimated a lot...

We can go to original source

It's only one sheet of paper -I have about 30-35 pages of orgins of the Burlinghton taken from old GSPO. Autor od the article about erly Burlinghton (Paweł Przeździecki) find most of the document and mucht more then is avaible on the internet. He's values about Burlinghton are not taken from that one paper, but whole declassified Burlinghton files. Im translated what he wrote in that article. And really if he claimd that in article (marked on red) then he found this in declassified Burlinghton files.
Of course I don't even think that you try to make cheap disinformation -cause both of us know other "original source" part:




Uploaded with ImageShack.us

and as I said - Paweł Przeździecki have right in his Burlinghton deciption.

127 mm and 152 mm with great cone angle of 60 degrees. Your perforation estimate is not correct because there is no such direct relation with diameter. Greater cone angle (from 25...60) implies reduction in jet maximum speed and lenghtening which results in less perforation ability, so for this case there is not any 600 mm.

Sorry Lidsky but this is bullsit. For 60 degree copper insert perforation for HEAT (SC) warhed is 4 4.5 diameter.
127x4-4.5= 508-570mm RHA perforation
152x4-4.5= 608-684mm RHA peration
And I have dozen pdf's and books about SC and HEAT warhed. For that copper insert and 60 degree and 1960-1970 decade we have penetration as 4-4.5 diameter. So in fact Burlinghton armour was able to stop given values: 600-680mm RHA penetration.

This armour stopped HEAT with penetration lower than thickness of the armour which is not anything special.

It's not true.
For 90. degree 203mm thick side Burlinghton module (and 50mm RHA hull side) was able to stop 84mm diametrer Carl Gustaw SC warhed.
In those years Carl Gustav have ~340-380mm RHA penetraion. Armour LOS (Burlinghton + hull side) have ~255mm LOS.
So on what accualy you based this "lower than thickness of the armour"? becouse it's nonsense and inconsistent with the source.

For 30-35 degree the same module whit LOS thickens 400-450mm and hull sides thicknes 100-120mm RHA provide protection against SC (HEAT) warhed 152mm dimatere whit 600-680mm RHA perforation. So again armour LOS was lowet then SC warhed penetration.

And about later Burlinghton:
Saying that it had such weight efficiency does not mean anything, because such efficiency had not only Burlington but it is given for many structures, and because we cannot consider the armour as a whole having in account volume and other factors. .

I have very accurate Leopard-2A4 gun mantled mask: dimensions, volume, mass.
The same for frontal turret armour. An mass efficiency for 1978 (1,5 vs KE, at least 3 vs HEAT) give us about 540mm vs KE and more then 1000mm RHA vs HEAT for Leopard-2A4.

 

[methos]

Sorry Lidsky but this is bullsit. For 60 degree copper insert perforation for HEAT (SC) warhed is 4 4.5 diameter.
127x4-4.5= 508-570mm RHA perforation
152x4-4.5= 608-684mm RHA peration

That's not really necessary... the image posted by you above says that the penetration into RHA is 28 inches (711 mm) for the 152 mm charge and 23 inches (584 mm) for the 127 mm charge.

 

[militarysta]

So 1:0 for Autor polish article about Burlinghton

 

[militarysta]

That's not really necessary... the image posted by you above says that the penetration into RHA is 28 inches (711 mm) for the 152 mm charge and 23 inches (584 mm) for the 127 mm charge.

BTW- do You want part about Germans view about Burlinghton, or You have this pages?

 

[methos]

If you mean the rest of these British documents - I have them.

 

[militarysta]

I think the efficiency of the NERA/bulging-plates array can easily be caluclated. According to Nii Stali bulging-plates armour can be up to 40% more effective than homogenous armour of the same weight. If I remember correctly Lidsky posted a similar value (30 to 40%?).
The array weighs as much as 152.8 mm RHA (weight equivalent to 150 mm RHA is generated by the steel part, weight equivalent to 2.8 mm RHA generated by 25 mm rubber). Thus the array should offer between 198 mm RHAe and 213 mm RHAe protection against shaped charges (152.8 mm multiplied by 1.3 - 1.4). This is not very much, maybe the slightly higher hardness of the thicker steel plates need to be taken into account...
If we use 500 to 520 HB steel plates (1,630 to 1,730 MPa) efficiency might increase to (1.3 x 135 mm + 2.8 mm + 15 mm) x 1.3 to1.4 = 251 - 270 mm RHAe vs CE.

my not very accurate metod about T-72B give as "low value" exatly 250mm vs HEAT...

I doubt that the three outermost steel layers are really RHA + HHS + RHA. Such a configuration would offer 40 mm + 50 x 1.34 + 40 mm = 147 mm RHAe protection.
In the firing tests these three layers were however simulated by using three 100 mm thick layers of steel (softer and cheaper steel). 147 /300 means a thickness efficiency of about 0.49... this is an incredible low figure (especially sine the steel was labeled armour steel). I have seen people using figures like 0.8 for mild steel (180 HB). 300 mm x 0.7 to 0.8 (for representing mild steel) = 210 - 240 mm RHAe
Assuming we have 40 mm RHA + 50 mm HHS + 40 mm SHS (i.e. a THS layout) we can easily get 130 mm x 1.6 = 208 mm RHAe... which is much closer to 30 cm mild steel as the former layout.

You know, I have really problem whit those 3x10cm armoured steel plates, becouse they have:
10cm+53cm "special armour" +10cm + 10cm =83cm Leopard-2A4 LOS.
So there are two option:
a) eacht 10cm plate is working as You describe: 40mm RHA + 50mm HHS +40mm SHS (THS)
b) eacht model is ended on second (after special armour) 10cm thick plate). But in that sense other plates haven't sense...

Generally what is Your idea about those 3x10cm plates?

I don't think that mixing armour from the early 1970s with armour from the early 1990s is going to lead to a proper result. What if the special armour cavitiy was smaller or greater on earlier tanks. What if the original tanks didn't have any kevlar in them?

Yes, it's problem IMHO we can assume layout for 1990 Leo-2A4 armour, but "german model for erly 1970" is quite consist whit some sources about germans armour before Burlinghton acess. And the problem is -what germans really chose for Leopard-2A0/A1? But for the other hand - turret ballance requires some mass ballance in armour too, so IMHO weight can't be to small.

 

[hest]

In "special armour" im mean that non passive multilayer structure placed inside tank armour LOS. In western (UK/USA) tanks it's place taken by Burlinghton armour, in German tanks it's those 500mm some armour fast-change module, and in Soviet armour we can say that "special armour" is active working filter -NERA style in T-72B and polyme cells in T-80U, behind without any doubt passive cast steel and passive RHA (HHS in fact) plate after NERA armour in T-72B and after polymer cells in T-80U.

Even if passive it is still considered composite structure (layers of steel, ceramics, space, etc), not homogeneous steel and it is most of volume of Western tanks. In Soviet you have greater use of steel in front and behind of filler.

OK, but those structue can't take more then 500mm from overal 840mm LOS. So what whit rest 340mm LOS?

Issue is that you want to apply it directly to Leopard 2 armour structure, but what you show belongs to a decade after and earlier Leopard 2 armour (1979...1980) does not necessarily has to be that. But you can take estimate for early version, and this kind of structure.

And the probplem is that HEAT protection don't even stnd (in those Nii Stali materials) to M.Held works about bulging plates, or with Balistic Symhosium thesis whit 2mm RHA + rubber +2mm RHA. In both cases NERA plates offer mucht better protection then Nii Stali claimd.
Even if wy take assume by russian sources T-72B protection against HEAT ad subtract from this value cast steel (passive) protection and those 45mm thick HHS palte then still we have for 5 NERA layers protection close to (depend on angle and No. of made mesurment) :
vs HEAT ~140-210mm RHA
vs APFSDS ~250-350mm RHA (and lower)
And those values have mucht more sense in conjunction with M Held, and other Balistic Symposium research. And some NERA layout used on M.Held or BS works are very primitive and simple -like those "erly german armour" or T-72B NERA, or Hadji armour from "T-55 Enigma".
So there is something not "OK" whit Nii Stali values -they are understimated a lot...

There are many references to those works. Account for single plate and whole armour structure are different things so you do not substract steel plates, etc protection coefficients (weight, thickness) are given having in account whole structure. For a single NERA plate you can reach to a mass coefficient of ...0.3 but we do not focus individually. In your case you do not apply coefficient only to chosen layers.

And you see by relation between thickness of armour of T-80U, T-72B and HEAT protection.

It's only one sheet of paper -I have about 30-35 pages of orgins of the Burlinghton taken from old GSPO. Autor od the article about erly Burlinghton (Paweł Przeździecki) find most of the document and mucht more then is avaible on the internet. He's values about Burlinghton are not taken from that one paper, but whole declassified Burlinghton files. Im translated what he wrote in that article. And really if he claimd that in article (marked on red) then he found this in declassified Burlinghton files.
Of course I don't even think that you try to make cheap disinformation -cause both of us know other "original source" part:

So important conclusion:

- What is shown is only theoretical estimate and not test result, even without real knowledge about 115 mm ammunition. So it is not true result but only estimation. And it is exactly what I was talking about earlier about Soviet tests

"Under angle of 60 degrees, both laboratory tests and field tests reflected the same relation between protection efficiency and physical-mechanical properties of materials. Howewer laboratory results were overstated in comparison with field tests, for example maximum mass coefficient of glass fiber reaches 0.72 which is gain in mass of 28%, while laboratory tests reflected 0.63 and even 0.53. This is due to lower supported pressure of the material of the projectile model used for laboratory tests so efficiency values of this table should not be taken as absolute."

In fact what you miss is that some effects were not fully known at that time, and developement of APFSDS greatly increased performance against angled armour (there is whole article about it as well as numerous studies and actual test results). Results proved to reconsider the "theoretical knowledge".

Until results of firing trials are available data must be regarded as best estimates...

)

This is only example, but problem is that we cannot know how it really is because:

1 You take estimates as actual results
2 You try to take it out of context

So this loosess against actual data.

and as I said - Paweł Przeździecki have right in his Burlinghton deciption.

Sorry Lidsky but this is bullsit. For 60 degree copper insert perforation for HEAT (SC) warhed is 4 4.5 diameter.
127x4-4.5= 508-570mm RHA perforation
152x4-4.5= 608-684mm RHA peration
And I have dozen pdf's and books about SC and HEAT warhed. For that copper insert and 60 degree and 1960-1970 decade we have penetration as 4-4.5 diameter.

I will not discuss values. So do I, and you should know as well that you cannot make such simple relation, neither can we be sure about actual performance.

So in fact Burlinghton armour was able to stop given values:

No, it was not able, it was estimated in best case .

It's not true.
For 90. degree 203mm thick side Burlinghton module (and 50mm RHA hull side) was able to stop 84mm diametrer Carl Gustaw SC warhed.
In those years Carl Gustav have ~340-380mm RHA penetraion. Armour LOS (Burlinghton + hull side) have ~255mm LOS.
So on what accualy you based this "lower than thickness of the armour"? becouse it's nonsense and inconsistent with the source.

Do you know characteristics of Carl Gustav warhead ?

I have very accurate Leopard-2A4 gun mantled mask: dimensions, volume, mass.
The same for frontal turret armour. An mass efficiency for 1978 (1,5 vs KE, at least 3 vs HEAT) give us about 540mm vs KE and more then 1000mm RHA vs HEAT for Leopard-2A4.

I wouldn't be so easy to make estimations without being certain that my data is valid and belongs to context...

 

[methos]

I think the efficiency of the NERA/bulging-plates array can easily be caluclated. According to Nii Stali bulging-plates armour can be up to 40% more effective than homogenous armour of the same weight. If I remember correctly Lidsky posted a similar value (30 to 40%?).
The array weighs as much as 152.8 mm RHA (weight equivalent to 150 mm RHA is generated by the steel part, weight equivalent to 2.8 mm RHA generated by 25 mm rubber). Thus the array should offer between 198 mm RHAe and 213 mm RHAe protection against shaped charges (152.8 mm multiplied by 1.3 - 1.4). This is not very much, maybe the slightly higher hardness of the thicker steel plates need to be taken into account...
If we use 500 to 520 HB steel plates (1,630 to 1,730 MPa) efficiency might increase to (1.3 x 135 mm + 2.8 mm + 15 mm) x 1.3 to1.4 = 251 - 270 mm RHAe vs CE.

I forgot to take the slope into account...

 

[hest]

Protection coefficient in function of weight is given for structures including frontal plate between 30 and 60 mm of steel, and back plate of at least 45 mm, not just for 5 bulging plates.

 

[militarysta]

Лукавая арифметика рейтингов - ВПК.name

Small interesting parts:

Устаревшая ДЗ

Вместе с тем установленная на танках Т-90 динамическая защита (ДЗ) «Контакт-V» надежно преодолевается БПС 829А2 и DM43 благодаря остроконечной конструкции их головной части без инициирования детонации Ð’Ð’ в ЭДЗ. Это было подтверждено результатами экспериментальных исследований, проведенных в НИИстали в конце 80-Ñ… годов, но по каким-то причинам оставшимися без внимания. Тогда ведущий инженер Петр Паластров модернизировал отечественный БПС 3БМ22 путем установки в его головной части «штыря» (рисунок 1а), диаметр которого составил 13,8 мм. Предполагалось, что при взаимодействии штыря с 15-мм стальной плитой встроенной ДЗ будет образовываться слабый осколочный поток, неспособный вызвать детонацию Ð’Ð’ в ЭДЗ. Стрельба этим снарядом подтвердила упомянутое предположение – детонация Ð’Ð’ в ЭДЗ не состоялась.

НИИ стали в основном вел отработку встроенной ДЗ «Контакт-V» с помощью БПС 3БМ22 «Заколка», головная часть которого представлена на рисунке 1b. При взаимодействии БПС с 15-мм плитой после смятия баллистического наконечника (1) пробивание плиты осуществляется демпфером-локализатором (2), диаметр которого увеличивается с 24 до 39 мм. Эти размеры и определяют создание мощного осколочного потока для возбуждения детонации в ЭДЗ. Созданию мощного осколочного потока способствует также материал 15-мм плиты – броневая сталь высокой твердости, которая обладает повышенной хрупкостью.

Какой же вывод следует из этого? Принятая в 1985 году встроенная ДЗ «Контакт-V» не пригодна для защиты от зарубежных БПС, имеющих остроголовые головные части. При взаимодействии таких головных частей образуется маломощный осколочный поток, который в результате гидроудара образует зоны, свободные от ВВ в ЭДЗ, что является одной из главных причин отсутствия детонации. Таким образом, ДЗ «Контакт-V» может работать только против отечественного БПС 2БМ22 «Заколка».

Не менее интересны результаты опыта (рисунок 2), проведенного в конце 1985 года Петром Паластровым. Встроенная ДЗ в этих опытах состояла из четырех ЭДЗ. Мощный осколочный поток от 15-мм плиты, образованный от соударения с БПС 3БМ22, инициировал детонацию в ЭДЗ (1), которая передалась всем последующим (2–4) благодаря их взаимному контакту. Разгон 15-мм плиты происходил под действием удара пластин ЭДЗ и расширяющихся продуктов детонации Ð’Ð’. Воздействие 15-мм плиты на боковую поверхность БПС явилось причиной его рикошета с образованием в бронеплите воронки глубиной 50 мм. Такой результат получен при детонации 1 кг Ð’Ð’ и массе 15-мм плиты 7,6 кг. Опыты Паластрова дают представление об особенностях возбуждения детонации в ЭДЗ и об энергетических возможностях воздействия ДЗ на БПС.

Во встроенной ДЗ «Контакт-V» под одной 15-мм плитой (размеры 500х260 мм) размещаются четыре секции, в каждой из которых уложены по два ЭДЗ 4С22. Секции отделены друг от друга стальными перегородками для непередачи детонации. Сравнивая конструкцию ДЗ «Контакт-V» с условиями опыта, можно отметить ее меньшую эффективность, которая определяется детонацией только двух ЭДЗ.

Таким образом, в оценках Виктора Степанова не использованы характеристики поражающего действия зарубежных противотанковых средств, которые надежно поражают танки Т-90А и Т-90АМ, что привело к завышению оценок защищенности наших бронемашин.

Встроенная ДЗ наших танков «Контакт-V» преодолевается: с вероятностью 0,8–0,9 современными зарубежными ПТУР малой дальности с тандемной БЧ – «Eрикс»; средней дальности – «Джавелин», «Дракон-2», «Милан-2T»; большой дальности – «Хеллфайр», «Бримстоун» и другими; зарубежными гранатометными выстрелами с тандемной БЧ; зарубежными БПС Ðœ829А1, Ðœ829А2, Ðœ829А3, DÐœ43, DÐœ53, имеющими остроконечную головную часть, позволяющую преодолевать ДЗ без детонации Ð’Ð’. Другими словами, наша встроенная ДЗ может бороться только со старыми боеприпасами, имеющими один кумулятивный заряд, или с отечественными БПС.

Следует отметить, что установка тандемной ДЗ «Реликт» на «крыше» танка Т-90АМ не спасает его от поражения авиационной ПТУР PARS 3LR (ФРГ), имеющей бронепробиваемость основного заряда тандемной БЧ 1200 мм и возможность атаки бронемашины сверху с углом встречи близким к 90 град.

More or less - even Russians slowly start to admitt that modern APFSDS can overpas ERA without problem. Interesting is part about DM43 and it's improved to overpass ERA tip (balistic cap). I don't known if is true, but DM43 was rejected (well not really, but it was accepted as minimum minimorum to overpas soviet tanks, but it was not future APFSDS) and new DM53 was developed whit completly diffrent mehanism to overpas modern ERA and main multilayer armour. And even after DM53 new DM63 was created, but here the point was propably overcome SC mehanism ERA (Nóż-Knife, etc).

 

[Damian]

MON jednak rozmawia o kolejnych Leopardach - DziennikZbrojny.pl

And interesting news, Polish MoD finally decided that more Leopard 2's will be purchased for the Polish Army. These will be also upgraded with allready used Leopard 2A4's that are used in the 10th Armoured Cavalry Brigade.

 

[Shirman]

MON jednak rozmawia o kolejnych Leopardach - DziennikZbrojny.pl

And interesting news, Polish MoD finally decided that more Leopard 2's will be purchased for the Polish Army. These will be also upgraded with allready used Leopard 2A4's that are used in the 10th Armoured Cavalry Brigade.

So U Guys r not goin for Leo-2 PL ( in which rhienmetall leo-2 evo is involved) in that upgrade or U will upgrade the new tanks to that level.