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Looking at it again - it now reminds me Merkava 3BdD and Merk 4 turret sides armor.

Yes, but which generation? I am well out of the loop nowadays, but I know of at least four generations of armour modules that I have climbed over. Remember, with fully modular armour arrays on the Merkava, they are changed at much more frequent intervals than most other modern MBTs. Given the IDF's somewhat limited resources, the modules are changed in small batches, but the technology of the modules is cutting edge; ahead of most to be honest.

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I suspect that NERA is used in those "composite" modules

 DGCb6ex.jpg

 

Super%2B60%2Barmor%2Bresized.jpg

 

http://otvaga2004.mybb.ru/viewtopic.php?id=1234&p=5#p631978

I wish I knew more about the armor modules on the Super 60.  I asked my Dad about it once since he worked at Teledyne in that period.  All he said was that the armor was done by a subcontractor and he didn't know any specifics about it.  This makes sense since Teledyne Continental was an engine company, not an armor maker.  

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Generally in older NERA armour packed "the main defender" is moving thiner back plate in eacht one NERA packed - in case T-72B it is those 3mm thick steel plate. During hit energy is transfering by rubber layer form front plate (21mm thick) to those 3mm thin metal plate. Ant this plate bulging and move is disturbing SC jet or bent "long rod". In mucht modern NxRA system the armour packed layout is diffrent - ussaly two thin (3-8mm) plates and thicker interlayer whit some "energetic" material. In sucht armour BOTH thin metal plates are moving - first backplate and as second - prontplate. So tehre is 2x more "moving and bulging  plates" then in older NERA armour.

 

Older one's type exmaple:

 

T-72B (Ob.184) armour:

https://zapodaj.net/images/386cbcc588bf1.bmp

 

jvAoVeX.png

 

T-55 Haji armour (on T-55 ENIGMA)

https://zapodaj.net/images/5f06c3f7eadd7.png

HtWP9Ak.jpg

 

 

 

And mucht more modern solution on Merkawa Mk.3D Dor Dalet - typical NxRA (both metal layer are moving):

https://zapodaj.net/images/6cda17836100e.jpg

 

i7fS3iH.jpg

 

 

 

EDIT - why I can't ad some photos? o.O

EDIT2 - hosting on imigur help a lot

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Click the "image" button and post the image URL in the text box that comes up.

 

Sometimes it works better if the images are re-uploaded to imgur.  For some reason our forum has issues sometimes with images hosted on servers outside the USA.

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This has probably been asked and answered before, but what is the approximate density of a NERA array?

 

I'm trying to use the tank design excel that Sturgeon provided, and it improbably gives a density of 8.74g/cm

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This has probably been asked and answered before, but what is the approximate density of a NERA array?

 

I'm trying to use the tank design excel that Sturgeon provided, and it improbably gives a density of 8.74g/cm

 

I would split the difference between rubber and steel for a start, so about 4.5 g/cm^3

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Looking at militarysta's post, it seems like a better estimate for NERA is something like 24mm steel + 6mm rubber + 22mm air. This gives a density of something like 3.75g/cm^3 if we use a rubber density of 1.1g/cm^3. So the total armour box probably clocks in just under 4g/cm^3.

 

Edit: the tank design spreadsheet is also very weird about NERA efficiency (0.44 vs KE and 0.34 vs HEAT). This means that, according to the calculator, you'd have to be a complete piker to actually use NERA for anything. Seeing as this is manifestly not the case, my guess is that the efficiencies quoted are bullshit.

 

Do we have any idea as to the real values?

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Looking at militarysta's post, it seems like a better estimate for NERA is something like 24mm steel + 6mm rubber + 22mm air. This gives a density of something like 3.75g/cm^3 if we use a rubber density of 1.1g/cm^3. So the total armour box probably clocks in just under 4g/cm^3.

 

Edit: the tank design spreadsheet is also very weird about NERA efficiency (0.44 vs KE and 0.34 vs HEAT). This means that, according to the calculator, you'd have to be a complete piker to actually use NERA for anything. Seeing as this is manifestly not the case, my guess is that the efficiencies quoted are bullshit.

 

Do we have any idea as to the real values?

 

That is bizarre.  Even dividing by the density relative to steel it still sucks on a mass basis.  Could the number be expressed as a reciprocal or something?  Most armor arrays are better vs HEAT than KE.

 

This site gives Burlington a mass efficiency of 3 vs shaped charges and 1.5 against KE.

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That is bizarre.  Even dividing by the density relative to steel it still sucks on a mass basis.  Could the number be expressed as a reciprocal or something?  Most armor arrays are better vs HEAT than KE.

 

This site gives Burlington a mass efficiency of 3 vs shaped charges and 1.5 against KE.

No, I checked out the values and the only thing better than plain old steel, according to the calculator, is triple-hardness steel. I think whoever made it either fucked something up or has a massive boner for the return of the King Tiger.

 

I'll plug in the proper values manually (thanks btw!) and run on that basis. 

 

Edit: having gone through the lookup table a bit, my best guess is that the author hates NERA for some reason. Some representative values for comparison (KE/HEAT):

  • 97% alumina (0.97/1.5)
  • 5083 Aluminium (0.43/0.7)
  • Chobham (0.71/1.17)
  • DU (1.5/1.5)
  • Konkat-5 (4.29/8.57)
  • plexiglass (0.4/0.7)
  • Steltextolite (0.41/0.7)
  • plain rubber (0.1/0.34)
  • Titanium-6Al-4V (0.86/0.61)
  • water 0.15/0.45)

So according to this thing it would be better to use anything, including raw rubber, than NERA in an armour array. Guess the tank designers of the world must be on crack.

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I grabbed the values from the worksheet after making a new set for NERA and compared the results in terms of average effectiveness/density. Here are the results after sorting:

  • air
  • Konkat-5
  • Relickt
  • NERA (new values)
  • Plexiglass
  • Fused silica
  • Chobham
  • Ceramics-alumina
  • various flavours of alumina
  • Steltexolite
  • Water
  • 85% alumina
  • Aluminum 2519-T87
  • Triple hardness steel
  • various flavours of steel, aluminium alloy or titanium alloy
  • mild steel
  • rubber
  • WHA
  • Depleted uranium
  • lead
  • NERA (original values)

Edit: the author just has a hate-boner for NERA and DU, I think.

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If the only thing that's showing as better than RHA is triple hardness then those are probably thickness efficiency figures, not mass efficiency figures.

 

They're still wrong, but that's at least part of what's going on.

Ah, you are correct!

 

The values are labelled TE (KE/HEAT)...

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No values

averaging it out and dividing by density just produces a relative scale, so no values are really needed unless you're looking for order-of-magnitude differences.

 

In any case:

 

 

Armor Type density (Ave TE/density)

Air - 100

 

Konkat-5 4S22 ERA - 1.05

Relikt 4S23 ERA - 0.96

NERA-Rubber (new values) - 0.60

Plexiglass - 0.49

Fused Sicila - 0.45

Chobham - 0.42

Ceramics-Alumina - 0.41

AD-90 (90% Alumina) - 0.33

AD-97 (97% Alumina) - 0.33

AD-92 (92% Alumina) - 0.32

Steltexolite - 0.32

Water - 0.3

AD-85 (85% Alumina) - 0.27

Aluminum 2519-T87 (MIL-DTL-46192 (MR)) - 0.20

RHA - Triple Hardness - 0.20

Aluminum AL-7039 (MIL-DTL-46063H) - 0.19

RHA - Russian-hardened - 0.17

RHA - High Hardness - 0.17

Aluminum 5083 (MIL-A-46026) Perforated - 0.17

Titanium-6Al-4V (MIL-A-46077) - 0.16

Titanium-6Al-4V (MIL-A-46077) - 0.15

RHA - Semi-Hardened - 0.15

RHA - Thin - 0.14

Aluminum 5083 (MIL-A-46026) Honeycombed - 0.14

RHA - American - 0.14

RHA - Russian-welded (WW2) - 0.13

RHA-Rolled - 0.13

Aluminum 5083 (MIL-A-46026) - 0.12

RHA-Perforated - 0.12

RHA - Cast - 0.12

Mild Steel - 0.11

Rubber (Some kind) - 0.10

 

WHA (HM1100) - 0.08

WHA (90% W) - 0.08

Depleted Uranium - 0.08

Lead - 0.07

NERA-Rubber (original values) - 0.04

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For the triple, here are the values scaled to RHA:

 

 

Armor Type Average relative to RHA

Air 785.00

Konkat-5 4S22 ERA 8.25

Relikt 4S23 ERA 7.53

NERA-Rubber (new values) 4.71

Plexiglass 3.85

Fused Sicila 3.56

Chobham 3.32

Ceramics-Alumina 3.18

AD-90 (90% Alumina) 2.62

AD-97 (97% Alumina) 2.55

AD-92 (92% Alumina) 2.49

Steltexolite 2.48

Water 2.36

AD-85 (85% Alumina) 2.12

Aluminum 2519-T87 (MIL-DTL-46192 (MR)) 1.59

RHA - Triple Hardness 1.56

Aluminum AL-7039 (MIL-DTL-46063H) 1.48

RHA - Russian-hardened 1.32

RHA - High Hardness 1.32

Aluminum 5083 (MIL-A-46026) Perforated 1.31

Titanium-6Al-4V (MIL-A-46077) 1.28

Titanium-6Al-4V (MIL-A-46077) Perforated 1.21

RHA - Semi-Hardened 1.17

RHA - Thin 1.12

Aluminum 5083 (MIL-A-46026) Honeycombed 1.12

RHA - American 1.10

RHA - Russian-welded (WW2) 1.02

RHA-Rolled 1.00

Aluminum 5083 (MIL-A-46026) 0.97

RHA-Perforated 0.92

RHA - Cast 0.91

Mild Steel 0.90

Rubber (Some kind) 0.75

WHA (HM1100) 0.66

WHA (90% W) 0.66

Depleted Uranium 0.63

Lead 0.52

NERA-Rubber (original values) 0.35

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Edit: the tank design spreadsheet is also very weird about NERA efficiency (0.44 vs KE and 0.34 vs HEAT). This means that, according to the calculator, you'd have to be a complete piker to actually use NERA for anything. Seeing as this is manifestly not the case, my guess is that the efficiencies quoted are bullshit.

 

Do we have any idea as to the real values?

 

Yes, I have a some "hard data" :-)

 

Polish very very primitive NERA for BRDM-2 upgrade, it was study project:

 

yd73zzX.jpg

bs2gMXR.jpg

XO2isod.jpg

ORCBucE.jpg

 

Offcial statment after tests:

 

W ramach sfinansowanego przez Ministerstwo Nauki i Szkolnictwa Wyższego pro-jektu rozwojowego nr 0019/T00/2008/06 zrealizowano w WITPiS program badań ekspe-rymentalnych z użyciem granatów PG-7M, o przebijalności stali RHA 300330 mm.

Przeprowadzono badania modelowych rozwiązań ekranów prętowych (rys. 1) i kaset typu NERA. Uzyskano rezultaty, dla których nie następuje przebicie pancerza

(...)

Kasety typu NERA mogą być obecnie stosowane dla cięższych pojazdów lub tylko fragmentami dla lżejszych (np. tylko do ochrony przestrzeni załogowej). Ze względu na ich budowę gęstość powierzchniowa tych rozwiązań wynosiła w trakcie badań od 220 do 390 kg/m2. Skuteczność kaset NERA jest znacznie wyższa od skutecz-ności ochronnej ekranów prętowych.

Porównując gęstości powierzchniowe opracowanych konstrukcji, uzyskano roz-wiązania o dużej efektywności masowej w stosunku do stali RHA. Przebijalność tej sta-li dla granatu PG-7M wynosi 300÷330 mm tj. 2340÷2570 kg/m2. Dla kaset typu NERA, licząc gęstość powierzchniową osłony razem z pancerzem kompozytowym i spall-linerem, można uzyskać ochronę o efektywności masowej ok. 4÷4,5. Zastosowane wy-kładziny wewnętrzne (spall-linery) skutecznie redukują kąt rozlotu odłamków, zmniej-szając tym samym poziom zagrożenia zranieniem dla większej liczby osób znajdują-cych się wewnątrz pojazdu.

 

translate:

 

 

As part financed by the Ministry of Science and Higher Education pro-development project No. 0019 / T00 / 2008/06 was carried out in WITPiS research program experimental with grenade PG-7M whit steel penetration - 300-330mm RHA.

Conducted studies of model solutions screens pannels (Fig. 1) and the armour type NERA. The results obtained, for which there is no armor penetration

(...)

NERA cassette type can now be used for heavier vehicles or just for lighter fragments (eg. Only to protect the crew). Due to the construction of the density of the solution during the tests was between 220 and 390 kg / m2. The effectiveness of cassettes NERA is much higher than the effective-ness of the protective screens rod.

Comparing the density of developed surface structures obtained spread-linked with high efficiency mass relative to the RHA steel. Penetration of fixed-li for the grenade PG-7M is 300 ÷ 330 mm, ie. 2340 ÷ 2570 kg / m2. For cartridge type NERA, counting the density of the surface cover with composite armor and Spallliner, you can get the protection of the effectiveness of mass approx. 4 ÷ 4.5. O-used interior of the veil (Spall-liners) effectively reduce the angle rozlotu debris, reduce-stirring the same level of risk of injury to more people-smokers are inside the vehicle.

 

 

And second:

NERA layout effectivnes for diffrent energetic material in "bulging plates":

 

ynX0A19.jpg

 

303KOiv.png

 

 

 

if You want I can post more resercht like this above.

More or less - typicle SINGLE NERA layer vs typical (copper cone, RDX melt) SC warhed will give circa 22% penetration reduction.  In case other then rubber material - wy have circa 27% reduction for rather NxRA material then pure NERA. Not very impressive?

Vell, in modern tank we have a lot NERA layers:

 

IZwhWjn.jpg

 

6vMIZdo.jpg

 

(my model of known M1A1HA side armour...)

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OK, as exmaples german NXRA and NERA tests and...NxRA armour on Leo-2A5/A6(famous "wedges" on Leo-2A5)

 

X3VlqOm.jpg

 

qdc1SCw.png

btw: You can find those PFD by using title in google :-) Enjoy!

 

 

Soviet ERA and German double NERA:

nrcWF43.jpg

 

ps. and check this:

https://zapodaj.net/images/47b609390faa3.bmp

and find pfd via google - agin - Enjoy, it very good pdf :)

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This has probably been asked and answered before, but what is the approximate density of a NERA array?

 

I'm trying to use the tank design excel that Sturgeon provided, and it improbably gives a density of 8.74g/cm

His values for ERA are fucked as well. He has 6.12 g/cm³ for Kontakt-5.

 

It's actually ~3.05 g/cm³.

 

 

...it looks like he just multiplied the weight of a single Kontakt-5 sandwich by two, because you know, 2 sandwiches per block. ...THAT'S NOT HOW THAT WORKS, THAT'S NOT HOW ANY OF THIS WORKS.

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