Main Battle Tanks and Armour Technology

[Damian]

The array looks this way - 50mm HHS (1,3-1,34 TE vs KE, 1,3 TE vs CE) + 5mm Air (0 TE vs KE, 0,26 TE vs CE) + 50mm Ti + 10mm Rubber + 50mm Ti (0,56 TE vs KE, 0,79 vs CE) x 3 + 10mm HHS + 50mm AD-97 (0,97 TE vs KE, 1,5 TE vs CE) + 10mm SHS (1,2-1,25 TE vs KE, 1,2 vs CE) + 100mm RHA (1 TE vs KE, 1 TE vs CE) = 65-67/65mm RHAe vs KE/CE + 1,3mm RHAe vs CE + 61,6mm RHAe vs KE/86,9mm RHAe vs CE x 3 + 65-67/65mm RHAe vs KE/CE + 48,5/75mm RHAe vs KE/CE + 12-12,5/12mm RHAe vs KE/CE + 100mm RHA vs KE/CE = 475,3-479,8mm RHAe vs KE/579-584,2mm RHAe vs CE.

475,3-479,8mm RHAe vs KE + 120mm RHAe vs KE = 595,3-599,8mm RHAe vs KE
579-584,2mm RHAe vs CE + 440mm RHAe vs CE = 1,019-1,024,2mm RHAe vs CE.

With DU - 50mm HHS (1,3-1,34 TE vs KE, 1,3 TE vs CE) + 5mm Air (0 TE vs KE, 0,26 TE vs CE) + 50mm Ti + 10mm Rubber + 50mm Ti (0,56 TE vs KE, 0,79 vs CE) x 3 + 10mm HHS + 50mm DU (1,3-1,5 TE vs KE, 1,5 TE vs CE) + 10mm SHS (1,2-1,25 TE vs KE, 1,2 vs CE) + 100mm RHA (1 TE vs KE, 1 TE vs CE) = 65-67/65mm RHAe vs KE/CE + 1,3mm RHAe vs CE + 61,6mm RHAe vs KE/86,9mm RHAe vs CE x 3 (=184,8 vs KE/ 260,7 vs CE) + 65-67/65mm RHAe vs KE/CE + 65-75/75mm RHAe vs KE/CE + 12-12,5/12mm RHAe vs KE/CE + 100mm RHA vs KE/CE = 491,8-506,3mm RHAe vs KE/579mm RHAe vs CE.

491,8-506,3mm RHAe vs KE + 120mm RHAe vs KE = 611,8-626,3mm RHAe vs KE
579mm RHAe vs CE + 440mm RHAe vs CE = 1,019mm RHAe vs CE

So as You can see there is not much difference in KE/CE protection differences if I change composition. Of course if I didn't made a mistake in calculations. So I think that reasonable conclusion is that because we do not know exact composition, every option is possible.

We might also consider that we were fooled and the frontal armor is more passive, made from harder and densier materials with bigger TE, that there might be more steel? Who knows.

This seems to be a very complex issue, without knowing exact composition and design of the array, any estimation is possibly close to far from reality.

 

[militarysta]

Back to the gun mantled mask in T-xx and Leopard-2

And argument about how mantle is thicker does not serve, because in reality we all know that it is vulnerable.
(...)
You know in reality it will not protect corresponding ammunition at any normal range,

It's seems that I understimated Leopard-2 gun mantled mask:



So in Leopard-2A4 we have thick (42cm) gun mantled mask. As I decribed many times - when we count know volume (without gap for L-44, FERO and MG) and mass (630kg -in fact it's 680kg..so 8% more) and when we take known erly Burlinhton mass Efficiency (like 1,5 vs APFSDS and 3 vs HEAT in compared to homogeneous armor steel of the same weight.) then those gun mantled mask just must have protection like:
a) 270 mm vs APFSDS
b) 540 mm vs HEAT

but after whole gun mantled mask area we have another protection - it's "wiege" (gun mounted "frame" whit the "ball") and solid RHA plates around that place. RHA plateas after gun mantled mask have between 200-280mm RHA and only after "bearing attachment point" we have 80mm (but it's very very small area circa 4x20cm for one side). And "wiege" is solid alloy monoblock with openings for technical, MG, FERO, and L-44. Those part is 240mm thcik, and made propably from titanium (or simmilar).
Titanum efectivnes agaist KE is 0.8, agaisnt HEAT is verly low (about 0.2) as RHA plate. So 240mm thick weige is like ~190mm vs KE and max 50mm vs HEAT. Around "weige" we have generally 200-280mm RHA.
No we can add walues from gun mantled mask protection and "weige" protection (or RHA plates around weige)
a) 270mm vs APFSDS + 190mm RHA from "weige" protecton (or 200-280mm from RHA plates around weige ) give us at least
~460mm RHA vs APFSDS
b) 540mm RHA vs HEAT + 50mm RHA from "weige" protecton (or 200-280mm from RHA plates around weige ) give us at least
590mm RHA vs HEAT

Those value are definetly better then poor protection offer by weak gun mantled mask in T-xx and then only cast steel whit very diffrent thicknes (between 280 -340 -420-440mm and on corners of the area 480mm). So protection in T-xx tanks against KE and HEAT is the same in both cases (lack of "special armour") and when we take 0.9 (100mm cast steel works as 90mm RHA plate) the we have protection like:
250-306-370mm RHA vs HEAT and APFSDS on corner of the 85cm width area we have 430mm RHA protection (less then 8% of generall width).

More or less - protection offer by gun mantled mask in Leopard-2A4 is far far better.

 

[methos]

The array looks this way - 50mm HHS (1,3-1,34 TE vs KE, 1,3 TE vs CE) + 5mm Air (0 TE vs KE, 0,26 TE vs CE) + 50mm Ti + 10mm Rubber + 50mm Ti (0,56 TE vs KE, 0,79 vs CE) x 3 + 10mm HHS + 50mm AD-97 (0,97 TE vs KE, 1,5 TE vs CE) + 10mm SHS (1,2-1,25 TE vs KE, 1,2 vs CE) + 100mm RHA (1 TE vs KE, 1 TE vs CE) = 65-67/65mm RHAe vs KE/CE + 1,3mm RHAe vs CE + 61,6mm RHAe vs KE/86,9mm RHAe vs CE x 3 + 65-67/65mm RHAe vs KE/CE + 48,5/75mm RHAe vs KE/CE + 12-12,5/12mm RHAe vs KE/CE + 100mm RHA vs KE/CE = 475,3-479,8mm RHAe vs KE/579-584,2mm RHAe vs CE.

And again you simply randomly make up an armour array in your mind and assume that this would be somehow close to reality. Where exactly is the space for the NERA plates to bulge and why should they make of expensive and rare material like Titanium, which is according to older TankNet posts not really suited for NERA? In the T-72B the sandwich plates already have more space to bulge than they are thick and most other known NERA/bulging plates array have a similar (or even greater) space-to-plate-thickness ratio. How you want to bend two 50 mm Titanium plates with only 10 mm rubber? That's not really possible. There are many things simply not probable or realistical in your randomly chosen arrays.
But let me show why your math does not work. Let's assume the following array:
100 mm steel HB 550 + 100 mm steel HB 420 + 100 mm steel HB 270... using simply TE values the armour would be equivalent to something about 350 mm RHA (depending on which TE we use for the steel hardness)... but in reality armour protection due to synergestic effects will be easily above 400 mm RHAe (thanks to the plate thickness the T/D ratio should be good which means probably more than 450 mm RHAe). Then there are also effects like T/D ratio and free edge effect, which normally reduce armour protection in dependance of the projetile's shape and hit location. With plates of 10 mm - 50 mm thickness T/D effect should have much impact.

475,3-479,8mm RHAe vs KE + 120mm RHAe vs KE = 595,3-599,8mm RHAe vs KE
579-584,2mm RHAe vs CE + 440mm RHAe vs CE = 1,019-1,024,2mm RHAe vs CE.

...

491,8-506,3mm RHAe vs KE + 120mm RHAe vs KE = 611,8-626,3mm RHAe vs KE
579mm RHAe vs CE + 440mm RHAe vs CE = 1,019mm RHAe vs CE

Your figures (despite the way they were generated) support what I say. That's less KE protection than the late T-72B only adding the fuel tanks increases protection to above 500 mm RHAe. And once the fuel is reached, it will likely get incinerated forcing the crew to leave the tank.

So as You can see there is not much difference in KE/CE protection differences if I change composition. Of course if I didn't made a mistake in calculations. So I think that reasonable conclusion is that because we do not know exact composition, every option is possible.

Much of what you do is not possible.

We might also consider that we were fooled and the frontal armor is more passive, made from harder and densier materials with bigger TE, that there might be more steel? Who knows.

We don't know and it could be possible - but we know that all other arrays look different and that's why it is not probable without any further sources supporting your theories.

 

[militarysta]

Damian, hard to say but IMHO Methos have right here. If You want to count smth in this way count that what we know - T-64B layers, T-72B layers, T-80U layers or M1A1 from Iraq side turret modell. That what You are doing is rather pointles. You must known internal layout, and ompare result with vlume and mass.

 

[Damian]

But I agree. I think both of you misunderstood purpose of these calculations. Their purpose was to present variable possibilities depending on the array composition, I never said that this is representing reality, it only presents some possibilities, and shows that one or other claim is rather pointless without knowing how exactly armor look like.

Same goes for the Leopard 2 front turret armor model made by Militarysta, he and me seen only array, but the composite filler was hidden inside a box, so nobody really knows how that damn armor eaxctly looks like in reality.

Your figures (despite the way they were generated) support what I say. That's less KE protection than the late T-72B only adding the fuel tanks increases protection to above 500 mm RHAe. And once the fuel is reached, it will likely get incinerated forcing the crew to leave the tank.

Ahhh, but not exactly, I was trying to create armor array that will not be made from best possible materials. As for fuel incineration, again, it is not that easy. There was incident in 1991 during ODS that M1 was hit in to fuel tank and it did not incinerate, after short repairs tank went back in to action.

Besides this, we still do not know how exactly fuel tanks are designed, there might be series of steel plates inside.

We don't know and it could be possible - but we know that all other arrays look different and that's why it is not probable without any further sources supporting your theories.

And actually what do we know?

We know something about "Combination K" and T-72B armor array but... well that's all. We only seen armor fragments of different types and some prototypes. And again "Combination K" is far more passive armor with just layers of different density and might be and definetely is much more different than "Burlington" for example.

Also the argument that some material could not be used because it is expensive. Perhaps it was used but the question is about quantities?

Besides there is also a question of economy of different countries. While for example UK could not use SiC or Boron Carbide, USA or Germany could, of course there is question about quantity of specific material as % of whole armor array.

So again it is a question of variability of options, there is so many options that the result of calculations might be completely different from worst to best possible result.

I would be carefull with making claims that something is not probable.

Ok let's make a simplified model for T-72B.

Any idea about thickness of plates, both at 90 and 68 degrees?

 

[Damian]

Ok let's assume that the overall thickness of the glacis plate is 255mm @24,5 degrees from horizontal this should give a thickness of 611mm, seems reasonable.

This means array that's look this way - 80mm HHS + 10mm Rubber + 80mm SHS + 5mm Rubber + 80mm RHA.

HHS - 1,3-1,34 TE vs KE, 1,3 TE vs CE
Rubber - ?
SHS - 1,2-1,25 TE vs KE, 1,2 TE vs CE
RHA - 1 TE vs KE, 1 TE vs CE

104-107,2mm + ? + 96-100mm + ? + 80mm = 280-287,2mm RHAe vs KE @ 90 degrees from horizontal/675-692mm RHAe vs KE @ 24,5 degrees from horizontal.
104mm + ? + 96mm + ? + 80mm = 280mm RHAe vs CE @ 90 degrees from horizontal/675mm RHAe vs CE @ 24,5 degrees from horizontal.

Of course the lack of TE for rubber makes a problematic calculation, as well as lack of the the exact thickness of the armor array and each layer + I don't know how to calculate and include the bulging effect of the array.

For comparrision

With DU - 50mm HHS (1,3-1,34 TE vs KE, 1,3 TE vs CE) + 5mm Air (0 TE vs KE, 0,26 TE vs CE) + 50mm Ti + 10mm Rubber + 50mm Ti (0,56 TE vs KE, 0,79 vs CE) x 2 + 10mm HHS + 50mm DU (1,3-1,5 TE vs KE, 1,5 TE vs CE) + 10mm SHS (1,2-1,25 TE vs KE, 1,2 vs CE) x2 + 100mm RHA (1 TE vs KE, 1 TE vs CE) = 65-67/65mm RHAe vs KE/CE + 1,3mm RHAe vs CE + 61,6mm RHAe vs KE/86,9mm RHAe vs CE x 2 (=184,8 vs KE/ 260,7 vs CE) + 65-67/65mm RHAe vs KE/CE + 65-75/75mm RHAe vs KE/CE + 12-12,5/12mm RHAe vs KE/CE x 2 (= 284-309mm vs KE, 304mm vs CE) + 100mm RHA vs KE/CE = 633,8-660,8mm RHAe vs KE/731mm RHAe vs CE.

So again, depending on array composition, different result. However in this example I need to adjust whole array thickness, so it is not 100% accurate.

BTW I am a bit tired so I do not making it especially accurate, give me a day or at least several hours.

 

[Damian]

However Paul Lakowski made such calculations:

M1A1HA - hull "beak" - 580-630mm RHAe vs KE and 800-900mm RHAe vs CE, and he assume that general frontal array would be made from steel, DU (50% steel and 50% DU), Kevlar and AD-92.

However as far as I know, his more accurate calculations were never published, as he planned to wrote a book.

 

[Damian]

As for fuel tanks, 27 February 1991 south west of Basra, M1A1 or M1A1HA, bumper number HQ66 (commander tank of TF4-64 Armor from 24th ID) was hit by conventional KE and HEAT ammunition (probably 100mm), the front fuel cell had been punctured and GPS (Gunner Primary Sight) damaged, GPS had been replaced next morning and tank as well as it's crew continued fight.

It seems that fuel tanks are not that vurnable as it might look like.

Besides this, we know from WWII for example that fuel was never the real reason fo vehicle burning, most of such incidents were cause by ammunition cook off's.

 

[militarysta]

And I made mistake in compare mas (kg of armoured steel) in turret armour for T-72B and Leopard-2A4.

T-72B nacked turret weight not 11 600kg but, only circa 8 688 kg. It change a lot.

First I will make sevral general assumptions:

1. Leopard-2A4 turret have frontal volumen 20% bigger then T-72B.
2. BUrlinghton style armour in Leopard-2A4 have mass efficiency -at lest 1,5 x kg vs KE and at lest 3 z kg vs HEAT -according to the data from 1978, and posted in two greate articles about erly Burlinghton ( I've already quoted them before)
3. The same mass efficiency is taken for T-72B "NERA style" special armour -maybe it's revaluation but I'd rather prefer to overestimated soviet tank then understimated.
4. In T-72B 80% turret mass is taken for frontal protection (+/- 30.degree) - rest (20%) of nacked turret mass is taken for roof, rear sides and turret back. So from 8 680kg it give 6 950kg (inluding NERA special armour). Both NERA armour inserts weight 740kg, so rest of turret armour weight 6 210kg.
5. From known Leopard-2A4 "special armour mass" 8 900kg ~22% is taken for turret sides, so only frontal armour (+/-30 -without turret sides) we have 6 942kg

Now small compare:
T-72B 6 210kg of cast steel turret x0.9 as RHA converter = 6 210kg x0,9= 5 588kg. So whole cast steel T-72B turret armour act like 5 588kg RHA. Now "special armour" cavities (both NERA inserts).
Against APFSDS: 740kg x 1,5 = 1100kg, and against HEAT: 740kg x 3 = 2220kg. So those values are RHA equivalent, and we shoud add them to previous mass.
5 588kg + 1100kg RHA= ~6 688 kg stell armour vs APFSDS
5 588kg + 2200kg RHA= ~7 788kg stell armour vs HEAT


Leopard-2A4 turret weigh 16t, special armour weight 8 900kg, 22% of it ist taken for turret sides, so for +/-30. we have only 6 942kg of special armour. Now x 1,5 vs APFSDS and x 3 vs HEAT:
10 410kg RHA vs APFSDS
20 826kg RHA vs HEAT

Now compare for both tanks:

vs APFSDS
T-72B : 6 688 kg stell armour vs APFSDS
Leopard-2A4: 10 410kg RHA vs APFSDS

So leopard-2A4 armour have 35% more kg of steel armour for protection. Even if Leopard-2A4 turret is 20% bigger in frontal area (in fact 15%..) then still Leopard-2A4 is at least 15% better (in fact about 20%).


vs HEAT:
T-72B ~7 788kg stell armour vs HEAT
Leopard-2A4: ~20 826kg RHA vs HEAT

So Leopard-2A4 have ~63% more kg of steel armour for protection. And even if Leopard-2A4 turret is 20% bigger in frontal area (in fact those value is equal 15%..) then still Leopard-2A4 is at least 43% better (in fact about 48%).

So as I wrote -in reality, Soviet cast steel turets shoud have less density protction in kg of RHA plates equivalent. And whe take only one from many factor - how many kog of steel plates is placed in some volumen. When we included other factor like:
- higher hardnes of western plates included in armour
- fact that stack of steel plates whit the same weight and thckness is 1.2 better then RHA monoblock
and others
then this difference will be even greater (against soviet tanks).


btw: in many estimatous T-72B have basic armourlike <540mm RHA vs KE and <600mm vs HEAT if for kg of armour data for Leopard-2A3/A4 are 15% (in fact 20%) better in first case, and 43% (in fact about 48%) in second case, then Leopard-2A4 armour should be like ~620mm RHA vs APFSDS and...~860 vs HEAT at least if we take only those one factor described above. In fact diffrence in HEAT protection is even bigger -for many causes - for example -Burlinghton features.

 

[Damian]

I am calculating TE for some time, and I get impression that if we assume the most probable array configuration for the front hull, we will achieve still very good protection against KE and also against CE, actually I made a more accurate model. I made assumption that in all modern MBT's front hull armor is approx ~700mm thick.

A - Outerplate

50mm HHS + 5mm Air + (65mm vs KE/65mm + 1,3mm vs CE) = 65mm vs KE/66,3mm vs CE

B - NERA Array

30mm HHS + 10mm Rubber + 10mm HHS + 5mm Air + (39mm + ? + 13mm vs KE/39mm + ? + 13 + 1,3mm vs CE)= 52mm vs KE/53,3mm vs CE

30mm HHS + 10mm Rubber + 10mm HHS + 5mm Air + (39mm + ? + 13mm vs KE/39mm + ? + 13 + 1,3mm vs CE) = 52mm vs KE/53,3mm vs CE

30mm HHS + 10mm Rubber + 10mm HHS + 5mm Air + (39mm + ? + 13mm vs KE/39mm + ? + 13 + 1,3mm vs CE) = 52mm vs KE/53,3mm vs CE

C - Steel/Ceramics Array

20mmHHS + 20mm AD-97 + 10mm HHS + 5mm Air + (26mm + 19,4mm + 13mm vs KE/26mm + 30mm + 13mm + 1,3mm vs CE) = 58,4mm vs KE/70,3mm vs CE

20mm HHS + 20mm AD-97 + 10mm HHS + 5mm Air + (26mm + 19,4mm + 13mm vs KE/26mm + 30mm + 13mm + 1,3mm vs CE) = 58,4mm vs KE/70,3mm vs CE

20mm HHS + 20mm AD-97 + 10mm HHS + 5mm Air + (26mm + 19,4mm + 13mm vs KE/26mm + 30mm + 13mm + 1,3mm vs CE) = 58,4mm vs KE/70,3mm vs CE

20mm HHS + 20mm AD-97 + 10mm HHS + 5mm Air + (26mm + 19,4mm + 13mm vs KE/26mm + 30mm + 13mm + 1,3mm vs CE) = 58,4mm vs KE/70,3mm vs CE

D - Steel/DU Array

20mm HHS + 20mm DU + 10mm HHS + 5mm Air + (26mm + 26mm + 13mm vs KE/26mm + 30mm + 13mm + 1,3mm vs CE) = 65mm vs KE/70,3mm vs CE

20mm HHS + 20mm DU + 10mm HHS + 5mm Air + (26mm + 26mm + 13mm vs KE/26mm + 30mm + 13mm + 1,3mm vs CE) = 65mm vs KE/70,3mm vs CE

20mm HHS + 20mm DU + 10mm HHS + 5mm Air + (26mm + 26mm + 13mm vs KE/26mm + 30mm + 13mm + 1,3mm vs CE) = 65mm vs KE/70,3mm vs CE

E - Backplate

95mm RHA = 774,6mm RHAe vs KE/813,3mm RHAe vs CE

HHS – 1,3 TE vs KE/1,3 TE vs CE
AD-97 – 0,97 TE vs KE/1,5 TE vs CE
DU – 1,3 TE vs KE/1,5 TE vs CE
RHA – 1 TE vs KE/1 TE vs CE
Air – 0 TE vs KE/0,26 TE vs CE
Rubber - ? TE vs KE/? TE vs CE

I used the lowest known TE values, and used one of the more logical configurations with the cheaper and more widespread materials. However I did not included T/D and Edge Effect.

Of course again, we have here variability based on composition. If someone wish, he can change composition and calculate it again. For example by reducing Stee/Ceramics number of layers to 3 or 2 and increasing NERA array layers.

PS. I think I know what is wrong. It is immposible to include in to calculations such effects like penetrator yaw, bending, breaking it in so smaller fragments, same applies to the armor and shaped charge jet interaction, because the calculation is probably mostly designed for completely passive and if possible homogeneus armors, not the more advanced arrays.

 

[hest]

And I made mistake in compare mas (kg of armoured steel) in turret armour for T-72B and Leopard-2A4.

Volume account is not correct, so is mass coefficient (mass/volume).

For example late 70s (1978 ?) composite armour test in Western Germany against kinetic rounds and ATGM.

6 blocks placed at 60 degrees from vertical.1 - multilayer structure, 35 mm steel plate with hardness between 1430 - 1630 MPa + 5 mm rubber layer + 3 mm medium hardness steel plate. 2- 25 mm steel plate of 1630 - 1730 MPa + 5mm rubber + 3 mm medium hardness steel. 3, 4, 5 - same as 2. 6- 50 mm steel plate of maximum 1220 MPa.

Space (distance from normal of plate) between first and second, fith and sixth is 50 mm, between second and third, third and forth, forth and fifth is 35 mm.

Area was 1 cuadratic meter, overall weight was 1570 kg, .

Second target representing side armour consisted of 5 blocks placed at 60 degrees. 1, 2, 3 were the same, 25 mm steel of 1630 - 1730 MPa + 5 mm rubber + 3 mm medium hardness steel. 4- 40 mm steel of 1330 - 1430 MPa and same rubber and steel. 5- 40 mm steel plate of 1020 - 1220 MPa. Space (from normal of plate) between first and second, second and third was 35 mm, between fourth and fifth was 60 mm. Area was 1 cuadratic meter and weight, 1310 kg.

So you see what is density (mass/volume) of composite armour. It always is significantly less than steel (has to be) mainly due to space required between elements to allow semi-active effect, bulging, etc.

In T-72B you have composite with similar characteristics as Leopard 2A4 in density or not much difference in that aspect. Difference is that T-72 armour has much greater use of steel without any space while Leopard 2 is the opposite, composite blocks make the most of the volume, and that volume is notably greater if compared directly with T-72, surface and thickness.

To be what you claim, T-72B active armour part should be drastically lighter but such difference is hardly possible, less if we know it's structure.

 

[methos]

But I agree. I think both of you misunderstood purpose of these calculations. Their purpose was to present variable possibilities depending on the array composition, I never said that this is representing reality, it only presents some possibilities, and shows that one or other claim is rather pointless without knowing how exactly armor look like.

Yes it shows that it is possible to have 600 - 700 mm thick armour which offers more protection than the late T-72/90 armour without (still without Kontakt-5). But you reprentations fail because they are not taking into account specific factors like weight (unless you would field a composite armour array with mass efficiency worse than original Burlington), price (titanium and SiC are damn expensive) and somtimes sense (you simply put ceramic tiles between steel, but in reality ceramics are use with a space-inefficient backing and Paul Lakowski also takes this into account & NERA does need space to work efficiently).

We know something about "Combination K" and T-72B armor array but... well that's all. We only seen armor fragments of different types and some prototypes. And again "Combination K" is far more passive armor with just layers of different density and might be and definetely is much more different than "Burlington" for example.

We also know the armour array of the T-55AM, T-54 Enigma, drawings from Burlington and we know roughly how the side armour of the M1A1HA and the "Chobham armour" on the Warrior look like.

Also the argument that some material could not be used because it is expensive. Perhaps it was used but the question is about quantities?

Besides there is also a question of economy of different countries. While for example UK could not use SiC or Boron Carbide, USA or Germany could, of course there is question about quantity of specific material as % of whole armor array.

I think it is much more likely that the UK could afford using SiC or B4C than the U.S. or Germany, because the UK bought "only 400" compared to some 2,125 Leopard 2 and more than 8,000 M1 Abrams tanks.

Ok let's make a simplified model for T-72B.

Any idea about thickness of plates, both at 90 and 68 degrees?

We were talking about the late production model, but given that the interlayer should be 105 mm from 90° and that the central layer has about the same thickness as the outer and innermost layer (50 - 60 mm) the best guess would be 60 mm. However this is just a simple drawing which does not necessarily present the thickness for scale.

Ok let's assume that the overall thickness of the glacis plate is 255mm @24,5 degrees from horizontal this should give a thickness of 611mm, seems reasonable.

It is 235 mm at 68.5° (648 mm) or 235 mm at 68° (627 mm). CIA says the ngle is 68.5°, common internet (and literature) value is however 68°.

This means array that's look this way - 80mm HHS + 10mm Rubber + 80mm SHS + 5mm Rubber + 80mm RHA.

According to Russian claims rubber is only used on late T-72B, I don't know what they used on earlier models.
20 mm HHS + 60 mm RHA + x mm space and polymer + 60 mm SHS/HHS + x mm space and polymer + 50 mm RHA @68(.5)°

As for fuel tanks, 27 February 1991 south west of Basra, M1A1 or M1A1HA, bumper number HQ66 (commander tank of TF4-64 Armor from 24th ID) was hit by conventional KE and HEAT ammunition (probably 100mm), the front fuel cell had been punctured and GPS (Gunner Primary Sight) damaged, GPS had been replaced next morning and tank as well as it's crew continued fight.

It seems that fuel tanks are not that vurnable as it might look like.

Besides this, we know from WWII for example that fuel was never the real reason fo vehicle burning, most of such incidents were cause by ammunition cook off's.

That in one single case the fuel didn't start to burn doesn't mean that this won't happen in another case. In Afghanistan the Marder IFV wasn't hit very often, still one shot managed to incinerate the Diesel fuel (which is harder to incinerate than the current U.S.' JP-8). The vehicle had to be abandonned.

I am calculating TE for some time, and I get impression that if we assume the most probable array configuration for the front hull, we will achieve still very good protection against KE and also against CE, actually I made a more accurate model. I made assumption that in all modern MBT's front hull armor is approx ~700mm thick.

A - Outerplate

50mm HHS + 5mm Air + (65mm vs KE/65mm + 1,3mm vs CE) = 65mm vs KE/66,3mm vs CE

I used the lowest known TE values, and used one of the more logical configurations with the cheaper and more widespread materials. However I did not included T/D and Edge Effect.

Of course again, we have here variability based on composition. If someone wish, he can change composition and calculate it again. For example by reducing Stee/Ceramics number of layers to 3 or 2 and increasing NERA array layers.

Your array again will unlikely find use in real life. It weighs as much as 655 mm steel armour, but the hull on Leopard 2/M1 Abrams does not weigh more than the Chieftain's hull (which has below 400 mm steel armour). Some weight might be safed to the M1/Leopard 2 being more modern, but not enough to allow an armour weight increase by more than 50%.

Volume account is not correct, so is mass coefficient (mass/volume).

For example late 70s (1978 ?) composite armour test in Western Germany against kinetic rounds and ATGM.

6 blocks placed at 60 degrees from vertical.1 - multilayer structure, 35 mm steel plate with hardness between 1430 - 1630 MPa + 5 mm rubber layer + 3 mm medium hardness steel plate. 2- 25 mm steel plate of 1630 - 1730 MPa + 5mm rubber + 3 mm medium hardness steel. 3, 4, 5 - same as 2. 6- 50 mm steel plate of maximum 1220 MPa.

Space (distance from normal of plate) between first and second, fith and sixth is 50 mm, between second and third, third and forth, forth and fifth is 35 mm.

Area was 1 cuadratic meter, overall weight was 1570 kg, .

Second target representing side armour consisted of 5 blocks placed at 60 degrees. 1, 2, 3 were the same, 25 mm steel of 1630 - 1730 MPa + 5 mm rubber + 3 mm medium hardness steel. 4- 40 mm steel of 1330 - 1430 MPa and same rubber and steel. 5- 40 mm steel plate of 1020 - 1220 MPa. Space (from normal of plate) between first and second, second and third was 35 mm, between fourth and fifth was 60 mm. Area was 1 cuadratic meter and weight, 1310 kg.

Is there any further of this tests available?

 

[Damian]

Yes it shows that it is possible to have 600 - 700 mm thick armour which offers more protection than the late T-72/90 armour without (still without Kontakt-5). But you reprentations fail because they are not taking into account specific factors like weight (unless you would field a composite armour array with mass efficiency worse than original Burlington), price (titanium and SiC are damn expensive) and somtimes sense (you simply put ceramic tiles between steel, but in reality ceramics are use with a space-inefficient backing and Paul Lakowski also takes this into account & NERA does need space to work efficiently).

We need to consider that later NATO armors are weight inefficent, look at the weight increase in these vehicle, it mostly comes from armor improvements. As for sense, why ceramics can't be encased in steel? It makes sense, ceramics are brittle and can very well interact with HHS as outerplate and perhaps HHS or something else as backing.

As for space, I included 5mm airgaps, is it too small?

I think it is much more likely that the UK could afford using SiC or B4C than the U.S. or Germany, because the UK bought "only 400" compared to some 2,125 Leopard 2 and more than 8,000 M1 Abrams tanks.

Well, not likely, you can't cheat economy. If you are increasing quantity of product that will be manufactured, costs go down. So actually 400 Challenger 1's were more expensive for UK and their econmy than 8,000 M1's for USA and their economy. Also we do not know if the price of vehicle includs costs of armor, at least not in USA, where armor is manufactured by separate goverment departament (departament of energy) not by GDLS or any other subcontractor, so the funding for armor might come from a different source. Don't know how it looks in Germany.

Your array again will unlikely find use in real life. It weighs as much as 655 mm steel armour, but the hull on Leopard 2/M1 Abrams does not weigh more than the Chieftain's hull (which has below 400 mm steel armour). Some weight might be safed to the M1/Leopard 2 being more modern, but not enough to allow an armour weight increase by more than 50%.

AFAIK M1's hull weight with partially mounted suspension and nothing else, approx 36 metric tons. The hull sides are ~60-70mm thick over crew compartment, 40mm thick in suspension attachement belt and over engine compartment, 40mm at the rear, 40mm over the belly, 50mm glacis and 20-40mm thick top over engine compartment. So the most weight will be generated by the front hull "beak" composite armor, the question is how much. Similiar situation in case of Leopard 2.

 

[Damian]

Methos I was searching how exactly expensive is B4C, didn't found much, however Ceradyne offers ballistic protection made from this material, and Goodfellow company also have such offer, for example 1,000g of B4C granule costs 355USD, while 4mm 50x50mm sheet costs 538GPB = 869,92USD.

It is expensive and definetely will not permitt to use in high quantities, on the other hand it is possible that it is used.

But it would be nice to know exact prices for a bigger and thicker plates made from B4C and SiC.

 

[Kunal Biswas]

Interesting prototype, Is this gepard predecessor..

 

[Damian]

Interesting prototype, Is this gepard predecessor..

No, it is one of DIVADS prototype.

 

[militarysta]

Volume account is not correct, so is mass coefficient (mass/volume).
(...)So you see what is density (mass/volume) of composite armour. It always is significantly less than steel (has to be) mainly due to space required between elements to allow semi-active effect, bulging, etc.

In T-72B you have composite with similar characteristics as Leopard 2A4 in density or not much difference in that aspect. Difference is that T-72 armour has much greater use of steel without any space while Leopard 2 is the opposite, composite blocks make the most of the volume, and that volume is notably greater if compared directly with T-72, surface and thickness.

Again - You don't understand my poin of view (or I don't clearly explaind that). I don't dispute that

significantly less than steel (has to be) mainly due to space required between elements to allow semi-active effect, bulging, etc

Becouse it's true.
But You completely neglecting the fact that Burlinghton style armour have some mass efficiency in kg armored steel (RHA). And when we included that fact then density vs KE is the same, in HEAT is mucht better.
In T-72B armour kg ofthe cast steel is 0.9 kg as RHA plate. + two 741kg weight NERA panells. In Leopard2 eacht 1 kg special arour works like at lest 1,5kg RHA vs APFSDS and 3kg vs HEAT. And this is diffrece.
If You want to talk about volument and area - important is only frontal area in m2 becouce Burlinghton is alway slighty thicker then other solutions. So important is kow many KG will be for m2 frontal protection. And result is not so very good for T-72B:


vs APFSDS
T-72B : 6 688 kg stell armour vs APFSDS
Leopard-2A4: 10 410kg RHA vs APFSDS

So leopard-2A4 armour have 35% more kg of steel armour for protection. Even after taking into account 25% bigger front turret, we have still 10% diffrence against T-72B.

vs HEAT:
T-72B ~7 788kg stell armour vs HEAT
Leopard-2A4: ~20 826kg RHA vs HEAT

So Leopard-2A4 have ~63% more kg of steel armour for protection. Even after taking into account 25% bigger front turret, we have still 38-40% diffrence against T-72B.

For example late 70s (1978 ?) composite armour test in Western Germany against kinetic rounds and ATGM.

Inteesting, could You give the source? Web page, artcile, post on some forum, etc?
This what You descrive looks like solutions between 1976 when Germnas had acess to the Burlinghton.

 

[militarysta]

BTW -if Lidsky describe correctly those German armour from 1970s. then it looks that:

 

[Damian]

This gave me some idea.

We know that from exterior, western tanks are boxy shaped and the armor inclination angles are not big but, what if the composite armor is inclined, both in hull and turret cavities in a much bigger angle? I mean the British tanks from exterior have shapes more accurately showing how armor is shaped inside, but Leopard 2 and M1 not, and in the same time, frontal armor in them might be also inclined more than external shape would suggest.

Dr. Gilber Harvey said that during R&D he observed that the array was more efficent if layers were inclined, so perhaps here is a key to more accurate estimations, because all of my current estimations were for plates at 90 degrees. IMHO the thickness of the cavity might be misleading as well.

 

[militarysta]

Those inclination angle can be not in vertical but hotizontal. In Leopard-2A4 turret verticaly it is 90. but horizontaly - 60 degree. IMHO special armour in frotnal part is sloppeed at 60 degree.