Main Battle Tanks and Armour Technology

[Damian]

Hmmm, the design of T-80U/UD armor is somewhat conceptually similiat to "Combination K", we can also make a simplified density model.

We know that the probably most common armor scheme for turret used is a cast basic structure with a polymer filler placed in sort of castings placed in two rows.

Cast steel is 7,86g/cm³ + (let's assume the polymer used is polycarbonate) 1,20g/cm³ + 1,20g/cm³ + 7,86g/cm³ = 18,12g/cm³ for the turret.

However the second armor scheme with Cermetal package should be slightly densier and should provide increase in hardness.

 

[hest]

It is including in my first draw. In T-80U it dosen't change for one simple reson -for 30-35 degree on right turret side LOS is still to small:

<440mm cast steel LOS, give us about 370mm RHA even with Kontakt-5 value in that place do not overcorss 500mm RHA vs KE. I fact both: DM33A1 and M829 have those value as guaranteed on 1300m distance. On Draw this without this place it will be like 3mm shorter right red mark area -so it doesn't change a lot (if change...).

It is close to correct measure, but:

Cast steel is of 85-90% equivalence to RHA. If we use 15% reduction, equivalence of steel + Kontakt-5 is over 500 mm RHA for LOS starting from ~ 436 mm in worst case. For best case (10% reduction) protection is over 500 mm for LOS starting from 412 mm.

So there is not any guarantee that simple monoblock DM-33 and M829 will defeat such zone. At the least it is not sure to just consider that "weak".

It included in western turret solution.

Suprise -only in hight. In width is the same/smaller then in T-72B or T-80U

Only for 0 degrees front, projection of frontal arc is significantly greater, also on same height as turret of T-80 you have upper part of hull of Leopard 2.

The issue is that the surface of Leopard 2 gun mantle is greater (in lenght it is similar to T-80U if you add 400 mm LOS + ERA part, mantle itself is smaller, and still bigger in height), we also have to add exposure of turret bustle. So the point is that even if angles look similar, weak zone of Leopard 2 will be greater in reality because of bigger vulnerable surface.

But the porblem is that they are the same/very simmilar in size:

Your measure

You see ? Even if compared with T-72B which has greater vulnerable zone than T-80U, it is comparable with Leopard 2 (despite that you did not consider sight gap, roof is not really vulnerable, neither you considered 35 degrees...), so in reality T-80U has better protection, and that is considering only from 0 degrees, (no turret bustle exposure, sight...)

 

[Damian]

so in reality T-80U has better protection

What means better protection? I allready made simple calculations that Soviet tanks armor is neither densier neither harder, it is actually less dense and similiary or less hard depending on composition.

At 0 degrees it have similiar thickness, at 30 degrees it's thickness is greatly reduced, to the level where protection even against older ammunition starts to be problematic.

Maybe it is moment when you face the truth, and admitt that Soviet T tanks are and were neither better protected, neither superior in anything to the NATO's 3rd generation MBT's.

However it does not mean they are not good designs, they are in their own way, but their superiority is just a creation of propaganda.

 

[Damian]

BTW if anyone could help my calculations to be more accurate and made to fit the specific tank. I would appreciate.

Especially that even if I reduce the number of layers, the density is still rather high. However I know that important here is also their size and volume of the whole array.

Although on the other hand from what I know, more important than density is hardness of armor.

 

[militarysta]

Back to the our little shitstorm about tanks

Yes, but most of uncovered areas are gun mantle, Luna searchlight, etc and having in account weak zones of all MBT can you say it is much worse ? For example surface is more or less analogous to Leopard 2. Point is that it is still majority, and there is great probability of survival, how do you think combat result should look like, tank will be defeated only because always they will hit at vulnerable zone ? It was actually nightmare that numerous tanks could be easily upgraded with ERA which greatly reduced possibilities to defeat. In most case it will be the opposite, and also T-72B was not the only threat neither the most dangerous of Soviet force.

When ~50% turret is not protected by ERA then possibility to hit in that area is 1/2 or P = ~0,5. So unocoverd area on T-72B model 1989 was serious problem. And im talking about that.

Militarysta, you do realise that there is gap due to sight placement, but you look only from 0 degrees perspective. How does it look like from 0-35 degrees left ? Side gap is more exposed, and in combination with huge mantle and armour placement it weakens protection of all left frontal arc. Also unprotected turret bustle is exposed from 30 degrees
Just look at example, it shows general idea

As I posted -area mark by degree when smth cant get trought "weak zone" is almous the same for T-80U and Leopard-2A4. Even when we included right side of the EMES-15 gap:

And If You want to not count place when LOS is bigger then 350mm cast steel+ Kontakt-5 then area is still simmilar (almoust the same):

And argument about how mantle is thicker does not serve, because in reality we all know that it is vulnerable.

Wow, wow, wow -not so fast!

You try to equate for one side 42cm thick and 93cm width gun mantled mask in Leopard-2A4 (circa 270mm RHA vs KE and 540mm vs HEAT) and for the other side -what accualy? nacked gap and between 280 and 300mm cast steel and only nera corrner of the 85cm width area we have 440-480mm cast sttel. Whole is around 250-270mm RHA bs KE and HEAT. Only near corners we have more (390-430mm vs KE and HEAT).
In fact gun mantled mask in Leopard-2A4 give better (more constans and without gaps) protection.
And even if 270mm vs KE and 540mm vs HEAT is not huge value then we shoud rember that in erly and half of 1980 it was enought to protect aginst most of infanty AT or 2A28 Grom from BMP-1. (btw -for any angle those walue incarase a lot)

About T-72B, upper part of roof is vulnerable (but not lowest)

Funny - those "not vulnerable lowest part of roof" is creally visible on photos from test on ex DDR tanks, and ex Polish (and others) and exatly in that place there are perforations by APFSDS.
here:

mirracle - "not vulnerable lowest part of roof" is perforated by DM33A1...

but there is ERA coverage -

And it was not enougt - and it was on of the resons why in T-80U developers rejected that solution (convex turret roof) and why in new welded turret developed in 1983/1984 (later on Ob.187, T-84, and T-90A) there is no crazy solution from deep 1960's.

It is present in all MBT, but in case of Leopard 2 mantle itself is bigger.

But whole "weak area" is amoust the same (8cm diffrent), and gun mnantled mask provide better protection then only cast steel whit very diffrent thicknes (between 280 -340 -420-440-480mm).

You know in reality it will not protect corresponding ammunition at any normal range,

Against all older RPG grandes (W, WM, WL-1977), 2A28 and SPG-9 munition (PG-9 granade) and older ATGM's -9M114, 3M6, 3M11/9M11, maybe 9M17/9M17M, and 9K115 Metys, 9M111 i 9M111-2, 9M111M, and maybe 9M111-2, 9M111M (generally Fagot), this protection was enought. More or less most of infanty AT weapons developed in 1970s.

and if according to you it is not only steel, then it can have even lower KE coefficient, which is not surprise because it is big volume to cover only with steel, due to weight.

according to myself when we count know volume (without gap for L-44, FERO and MG) and mass (630kg -in fact it's 680kg..so8% 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

Frontal projection which requires the most armour, weight is from 1/4 to 1/3 greater than in Soviet tanks

Like here:

In fact front area in m2 is almoust the same

, and protection of sides due to manual loader turret design, so it is very great issue. They are just unable for example to have such great part of high density, steel as "T" tanks.

You don't understand. If You want talk about "high density" cansider the fact that cast steel and some RHA plates in T-72B are..RHA plates, yes? Whole turret (shield) whit armour weight in T-72B circa 11 600kg. Inluding two "NERA inserts" (-both 741kg). Normlany only about ~75% will be armour protection (8 700kg) for +/- 30 degree (we not included roof, thin sides and rear turret).Without both NERA inserts it vill be ~8 000kg. Those 8000kg is for cast steel not for RHA so we should multiply that by 0.9 in best case. Result is ~7 200kg. Two NERA inserts weight 741kg and let's say that they had mass Efficiency like erly Burlinghton -1.5. So we have 7 200kg RHA + 741kgx1,5 = 7 200 + 1100kg RHA= ~8300kg RHA mass for T-72B.

In Leopard-2A4 turret weight is 16 000kg, but "armour" weight "only" 8 900kg -so in theory simmilar value for bigger volumen. 20% takes turret sides so "only" 7000kg is for frontal armour and its. But even erly Burlinghton special armour had mass Efficiency like 1,5 vs APFSDS and 3 vs HEAT in compared to homogeneous armor steel (like in T-72B is) of the same weight. So we have 7000x 1,5 and 7000x3 = 10.500kg and 21 000kg.
So if you want to talk about "high density, steel as "T" tanks." consider fact that in T-xx tank most of cast steel turrets is...only cast steel in KG, in western tanks known mass is at lest x 1,5 vs KE and 3x vs. HEAT
So in theory slighty smaller (15% for frontal m2) and shorter turret for T-72B have 8 300kg RHA and "huge" Leopard-2 turret have for frontal protection 10500kg (when we take kg x 1,5 = kg vs KE). Against HEAT it will be T-72B 7200kg + 741x3 (2220kg) = ~9420kg, in Leopard-2: 7000x3 =21 000kg so more then twice better.

Difrence in mass kg RHA for turret front for T-72B and Leopard-2A4 is:
vs KE:
T-72B: 8 300kg
Leopard-2A4: 10 500kg (so 20% better in Leopard-2A4 case -whit fully compensates sligty bigger frontal turret surface/area)

vs HEAT:
T-72B: 9420kg
Leoprd-2A4: 21 000kg (so 55% better in Leopard-2A4 case -what is far far better)


I don't know if I wrote that creally - in soviet tank fact that most of turet volumen is pure steel does not mean that western tank turrets, whit in theory less compact / dense Burlinghton style armour sandwich, had in result " less density" protection due to western Burlinghton and it clones mass efficiency -at lest 1,5 x kg vs KE and at lest 3 vs HEAT.
So in result (paradoxically) slighty bigger (in volument) western turrets have the same in "kg of density" vs KE armour, and almoust twice better in"kg of density" vs HEAT. And here fact that soviet tank have more in kg cast steel and less "special armour" works to the disadvantage way not advantage.
And we are talking ONLY about density and how many (finnaly) kg of RHA can be placed in some volument.

It is not correct. Protection research is not all performed by design bureau but by specialist institues, implementation is work for tank designers. Welded turrets were not all the same, they envolved over time so we cannot talk about one developement. Intellectual property of Soviet welded turret now belongs to NII Stali mostly, and UKBTM, and of course if you talk about armour structure, it has nothing to do with 80s.

I had both article writte by two very good polish tank journalists about Ob.187, and after that about Oplot-M and T-90MS. Both was written whit support and assistance UWZ and CHMBT and ther is very precisely describe about those welded turret. It was developed in 1983/1984 for new tank from Charkiv and for successor of the T-64. For many resons it was "frozen" since to Ob.187 and T-84. In fact those turret was redy in 1993 on Ukrina for test as T-84 turret.

There is always theoretical knowledge even if you haven't got it built, but developement process is not so easy, to guarantee defeat of late 80s armour it took germans a decade and with actual tests. Developement of Relikt "similar idea" took also great time and with extensive tests and data compilation (and greater study and knowledge about K-5 than anyone else). Now there is deployement of completely new armour structure, turret and ERA, and there is not any certainity that previous expwrience will serve now.

More or less DM-53 haven't any problem with Kontak-5 and about 630mm thick RHA monoblock after ERA. Few years later (6) was introdced new DM63 whit changed internal structure - after testSC ERA fom Ukraina,an "new" ERA and whole turrets stuff from other estern countres. The way to overcome ERA in both rounds: DM53 and DM63 have propably nothing common with tip used on americans M829 series, and it's closer to segment penetration mahanism with (propably) some PELE rounds mehanism used in first segment (my idea -I don't know the details). Anyway - western rounds (M829A3, DM53, DM63, M338) are more complicated then most person think, and they mehanism of overcoming ERA is very sophisticated.

I know it is not Burlington, but it was fielded in half of 80s and level is very weak

Ech...what You know about GB until Margaret T. period? The reson of stilbrew on Chft. whas diffrent - money, and problem with MBT-80 program. In fact due to money reson most prgrams in UK was frozen for 1973-1980 decade.

(compared to that they are indeed super armour, but in general not so...)

It was exmaple how good can be very very elry Burlinghton vs HEAT -as proof that solution for at les 1,5 decade later can have 800-1200mm RHA ve HEAT in Leopard-2 turret case. Like in AGDUS system.

And as I said ay evidence proof that those values:
protection for that Leopard2A3 and 2A4 (erly) can be as ~430-480-540mm vs KE and 850-954-1084mm vs HEAT (turret sides at 30. and hull front - turret front at 30. - turret front at 0.)

For 2A4 since 1986 IMHO it will be slighty bigger:
500-550-630mm vs KE and -1000-1150-1300mm vs CE ((turret sides at 30. and hull front - turret front ad 30. - turret front at 0.)
can be very possible...

 

[Damian]

Khem khem. As far as I read, the density per se is not most important factor for vehicle protection. Much more important is hardness, both against kinetic energy and chemical energy projectiles.

For example triple hardness steel would have thickness efficency of 1,8 against KE compared to thickness efficency of cast homogeneus armor of only 0,9-0,92.

Triple hardness steel have hardness of approx 500-600BHN.

A simple calculation, let's take a two armor plates one made from CHA and one from THS. Both plates have the same thickness of 50mm. How we calculate thickness efficency of plate?

CHA 0,9-0,92 TE vs KE x 50mm = 45-46mm
THS 1,8 TE vs KE x 50mm = 90mm

RHA TE = 1
DU TE = 1,5

Which means that a CHA armor 50mm thick gives protection like 45-46mm thick RHA plate, while THS armor of the same thickness gives protection equivalent to 90mm RHA plate.

So as we can see, hardness is very important.

So we can put it even more, if we assume that there are two armor arrays, each made from 3 layers.

Layer A is 50mm THS + 10mm DU + 50mm RHA = 90mm RHAe + 15mm RHAe + 50mm RHA = 155mm RHAe
Layer B is a 50mm CHA + 10mm DU + 50mm CHA = 45-46mm RHAe + 15mm RHAe + 45-46mm RHAe = 105-107mm RHAe.

So the density is less important here than hardness.

So use of cast steel and lack of use of higher than steel density materials, actually weakened soviet tanks armor. While the NATO tanks used rolled plates, and as far as we know, used steel types besides RHA were SHS, HHS, DHS and THS depending on generation + of course high hardness materials like ceramics and high density materials like DUA or WHA.

 

[Damian]

What is interesting for array A, if we would replace the last 50mm RHA layer with THS layer of the same thickness we would achieve protection equivalent of 195mm RHA with armor that is only 110mm thick.

So the key is hardness not density, density would be more important in the backing layer to stop what is left from projectile.

O so the calculation is simple.

Layer A is 50mm THS + 10mm DU + 50mm RHA = 90mm RHAe + 15mm RHAe + 50mm RHA = 155mm RHAe x 5 = 775mm RHAe vs KE
Layer B is a 50mm CHA + 10mm DU + 50mm CHA = 45-46mm RHAe + 15mm RHAe + 45-46mm RHAe = 105-107mm RHAe x 5 = 525-535mm RHAe vs KE.

We can also calculate this against CE.

THS TE vs CE = 1,3
DU TE vs CE = 1,5
CHA TE vs CE = 0,9-0,92

Layer A - 50mm THS + 10mm DU + 50mm RHA = 65mm RHAe + 15mm RHAe + 50mm RHA = 130mm RHAe x 5 = 650mm RHAe vs CE.
Layer B - 50mm CHA + 10mm DU + 50mm CHA = 45-46mm RHAe + 15mm RHAe + 45-46mm RHAe = 105-107mm RHAe x 5 = 525-535mm RHAe vs CE.

So the key is hardness, density and overall composition of the armor.

Of course this is still simplified model.

 

[Damian]

Ok I get this even better. For example M1 Abrams glacis plate. We know it is a 50mm probably HHS plate inclined at 8 degrees from horizontal.

So HHS 1,3-1,34 TE x 359mm (50mm@8) = 466,7-481,06mm RHAe vs KE. But now get this, if you replace HHS plate with THS plate you get such thing.

THS 1,8 TE x 359mm (50mm@8) = 646,2mm RHAe vs KE, preaty nice for a 50mm plate eh?

 

[militarysta]

Khem khem. As far as I read, the density per se is not most important factor for vehicle protection. Much more important is hardness, both against kinetic energy and chemical energy projectiles.

For example triple hardness steel would have thickness efficency of 1,8 against KE compared to thickness efficency of cast homogeneus armor of only 0,9-0,92.

Triple hardness steel have hardness of approx 500-600BHN.

A simple calculation, let's take a two armor plates one made from CHA and one from THS. Both plates have the same thickness of 50mm. How we calculate thickness efficency of plate?

CHA 0,9-0,92 TE vs KE x 50mm = 45-46mm
THS 1,8 TE vs KE x 50mm = 90mm

RHA TE = 1
DU TE = 1,5

Which means that a CHA armor 50mm thick gives protection like 45-46mm thick RHA plate, while THS armor of the same thickness gives protection equivalent to 90mm RHA plate.

So as we can see, hardness is very important.

So we can put it even more, if we assume that there are two armor arrays, each made from 3 layers.

Layer A is 50mm THS + 10mm DU + 50mm RHA = 90mm RHAe + 15mm RHAe + 50mm RHA = 155mm RHAe
Layer B is a 50mm CHA + 10mm DU + 50mm CHA = 45-46mm RHAe + 15mm RHAe + 45-46mm RHAe = 105-107mm RHAe.

So the density is less important here than hardness.

So use of cast steel and lack of use of higher than steel density materials, actually weakened soviet tanks armor. While the NATO tanks used rolled plates, and as far as we know, used steel types besides RHA were SHS, HHS, DHS and THS depending on generation + of course high hardness materials like ceramics and high density materials like DUA or WHA.

Damian this about density in leopard and T-72B was only
exampla how in thoae one factor western tank are not worse
in KE density case and far far better in vs HEAT density
case. Of course when we includedthat what
You post about hight hardness of steel plates in western tanks
and constans 270HB scale in cast soviet turrets whit mucht
smallerl special armour cavity then diffrence will be bigger and better for western turrets.

 

[Damian]

As a side note, Carbon Nano Tubes or Aggregated Diamond Nano Rods would have just just insane TE values for both KE and CE due to their incredible hardness and in the same time ductility as well as low or even very low weight, a perfect materials for armor, however there are still problems with manufacturing them in sufficent numbers and desired shape as well as in affordable price.

 

[methos]

Those values:
T-80U:
630-490mm RHA vs KE included Kontakt-5 ERA (without: 500-360mm RHA)
T-72B:
540-470mm RHA vs KE
T-72B model 1989 and erly T-90 (Ob.188):
670 -600mm RHA included Kontakt-5 ERA, but due to very poor coverated by ERA casette most turret have still this 470-540mm RAH vs KE.

I think the values are problematic. It always depends on how they are measured and what the estimate is. The CIA used two values - estimations for the "lower bound" and the "upper bound". One represented the worst possible case and the other the best possible case.
In T-72B (using the values from your image) the armour can be as effective as 480 mm RHA in the worst case (cast steel is 15% less effective than RHA, composite plates are using Aluminium and are not stronger than the thickness of their metals, the steel plate behind the sandwich plates in normal RHA), but in best case it can have armour as effective as 620 mm RHA against KE (cast steel is only 5% less effective than RHA, composite plates are made of RHA + rubber + HHS, HHS plate is behind the array, HHS is very high quality HHS). Fofanov quoted Russian sources that Soviet cast armour is between 5 and 15% less effective than RHA, he didn't say that it is exactly 15% worse than RHA. The Nii Stali contains some information about steel hardness and some of the alloy presented their are (good) HHS. They also do not say exactly how strong Kontakt-5 is - in the article about the T-72 and T-90 it is said to increase protection by 1.2 times. In the article about using Kontakt-5 on the T-55 they say that it increases armour protection so much that it can resist APFSDS with 400 mm penetration. And in the article about Kontakt-5 in the general armour section they say it increases armour protection on modern tanks by 1.2 to 1.5 times.
For the T-80U the values can be similar. Less than 500 mm RHAe in worst case, but above 600 mm RHAe in best case.

In the same

DM33A1 470mm RHA for 2000m (guaranteed) to ~520mm RHA for 2000m (achivable).
M829 540mm RHA for 2000m (G) to ~ ?? (achivable)

I disagree. The "540 mm at 2,000 m" are a value taken from Jane's. Jane's doesn't specify wether this is guaranteed penetration or achievable, they don't use a common measurement system. According to Odermatt and older posts from Lakowski it is probably not guaranteed penetration.

These features you talk about (M829A2, Dm-53), tip, segmented construction were known back during USSR times.

Improved tip which did not cause initiation, this was later implemented in rounds from Dm-43. All problems from numerous tests were gathered and used for developement programme under designation Relikt , which sunny thing is that rounds which exploit Kontakt vulnerability are much opposed to it.

Such techniques were already used in APFSDS from mid-1980s and is nothing special for 120 mm DM 43 or 120 mm DM 53.

First value + 130mm Kontakt-5 give us 720mm RHA second value give us 560mm RHA.

[...]

1. Kontak-5 ( act like 130mm RHA)

I did not manage to find any place on the Nii Stali website saying Kontakt-5 increases armour protection by 130 mm. I saw the values "increases protection by 1.2 times" in the article "UNIVERSAL DZ "CONTACT-V" for the T-72B and T-90", the statement "protection from BPS increased to 400 mm (105 mm BPS type M111 and NORINCO)" in the article "Tank T-55 with explosive reactive armor (ERA)" and "increases protection against armour piercing shells by 1.2 ... 1.5" in the article "PRINCIPLE dynamic protection of the 2nd generation (integrated or universal option)".
The names were translated by Google Translator.

Compare for both tanks (Soviet Union vs NATO) is interesting:
when value for 30. degree was typical for most of the tanks:
M1: ~560mm RHA
Leopard-2A4(late) 550mm RHA
T-80U 560mm RHA
T-72B model 1989 600mm RHA (Kontakt-5)
then value for 0. was quite impressive for T-80U:
M1: ~600mm RHA
Leopard-2A4(late) 630mm RHA
T-80U ~720mm RHA
T-72B model 1989 ~540mm RHA

I hope that "M1" here means M1IP/M1A1/M1A1HA?

NATO tanks:

KE could be above 500 mm RHA (turret only), but HEAT is totally incorrect, not even author in that journal gives such exageration, and it is not possible at that time, due to thickness and KE requirement which does not allow such optimisation. In reality for turret it was around 700 mm at most.

Protection against shaped charges with armour penetration greater than 1,000 mm into RHA is possible given the size, weight and (probable) construction of the NATO's armour. 700 mm RHAe protection is too less for most NATO anti-tank missiles of the late Cold War. MILAN 2, HOT 1 & 2, late TOW versions all could penetrate 800+ mm RHA.

Of course situation is different. 3BM42 Mango construction is optimised to defeat composite armour, or whitstand semi-active effect (segmented, etc) for example it will perforate Leopard 2 composite easier than T-80 hull composed mainly by steel, so it had possibility to defeat main turret armour, not to talk about hull.

3BM-42 Mango should be optimized to defeat composite armour? No way. 3BM-42 Mango uses a two-piece tungsten penetrator in a steel body... that's essentially 120 mm DM 13. Hevay metal penetrator in steel bodies proofed to be less effective against complex targets - that's why monobloc penetrators were introduced to replace them... both in NATO and in Soviet Union (Svinets, Lekalo, etc. are all monobloc).

Soviet tanks allways had problems due to ridicoulus requirements of vehicle size and weight, thus not allowing bigger composite filler volume per armor thickness ratio.

They could have put more composite armour into the same volume by reducing the thickness of the cast steel. But they didn't because the cast steel offered still reasonable protection (esp. with Kontakt-1 or Kontakt-5) while being much cheaper.

Actually western design have better designed hull and turret protection.

I think that (late) T-72Bs and T-90s might have better glacis armour at the place where Kontakt-5 is located (which has not very good coverage).

In first half of 1980's NATO field tanks that are on par with newest Soviet tanks at that time. In second half of 1980's NATO designs receive improvements that gaves them step by step superiority over Soviet designs.

Challenger 1 and early M1 (pre-1984) all had drawbacks which made them in many aspects worse than the top-line Soviet tanks of the same time (T-80B and T-80U). I would not call this "on par" but rather say that they were rapidly catching up.

If Soviet Union would be a threat for NATO in 1990's still, then when you would excite yourself with more and more incarnations of T-72's, NATO would field next generation of AFV's back then, USA based on M1 Block III a family of heavy platforms, Germany based on EGS/NGP.

NGP is the German Future Comat Systems and FRES equivalent, it is not much older than these programmes. Between Leopard 2 and NGP there was the very short living Panzerkampfwagen 2000.

Dimensions leopard-2 gun mantled mask are known, the same dimensions of blanks for L-44, FERO, and MG. And we know mass of gun mantled mask - 630kg. Rest is rather simple math base on qustion- how thick will be homogeneous steel armor block "inside" gun mask dimensions if it will be weight 950kg (630kg x1,5 vs APFSDS) and 1890kg (630kg x3 ve HEAT). The answer is:
a) 272 mm
b) 542 mm
So this protection offer by gun mantled mask should be:
a) 270 mm vs APFSDS
b) 540 mm vs HEAT

Behind the gun mantlet there is still the gun mount and a steel plate. This is considerable steel thickness, at the thickest places above 200 mm, at the thinnest places probably above 50 mm.




I am trying to catch up a little bit more with this topic, but there is a hell of a lot of posts to read and answer here.

 

[methos]

This image can only illustrate modern armour, but from a patent from a company which probably has nothing to do with the Leopard 2.

 

[militarysta]

methos you will have soon (5min) PM please check it.

 

[Damian]

I think that (late) T-72Bs and T-90s might have better glacis armour at the place where Kontakt-5 is located (which has not very good coverage).

Glacis yes, but in most NATO designs glacis is not the most exposed, but the "beak". If we count a simple TE values it will actually be in favor of the NATO designs "beak", however glacis is a bit different thing here. IMHO this is the problem, a confusion due to different concepts of the hull design and it's protection.

Challenger 1 and early M1 (pre-1984) all had drawbacks which made them in many aspects worse than the top-line Soviet tanks of the same time (T-80B and T-80U). I would not call this "on par" but rather say that they were rapidly catching up.

IMHO the biggest drawback of Challenger 1 was that damn rifled gun. The penetration capabilities for a 120mm calliber were just pathetic. For the M1 the biggest drawback would be probably the lack of panoramic CIV, and somewhat strange decision to stick with 105mm and make trails of the new gun so long. Definetly situation vastly improved in 1985 with armament and protection, while in 1988 the protection started to surpass potential adversaries.

Although HAP is still a bit of mystery when it comes to design.

 

[methos]

Glacis yes, but in most NATO designs glacis is not the most exposed, but the "beak". If we count a simple TE values it will actually be in favor of the NATO designs "beak", however glacis is a bit different thing here. IMHO this is the problem, a confusion due to different concepts of the hull design and it's protection.

I don't think so. Armour protection is a result of weight and space. The glacis of the late T-72B/T-90 weighs more than 500 mm RHA. The small amount of bulging plates is insignificant IMO for protection against KE, so the armour can be seen as an array of spaced steel layers (of different hardness). So the weight equivalency will be above 1, depending on the exact hardness of the layers. The weight efficiency of the armour against shaped is only slightly better.
The hull armour of the M1 Abrams and Leopard 2 is - at least as far my own measurments and some other sources show - not thicker (or if it is thicker then less than 5 cm). But I do not see why there should be much more weight. The hull of the Leopard 2 and M1/M1IP/M1A1 does not seem to have large weight reserves, especially if the armour needs also to protect against shaped charges. Burlington-style armour might have a weight efficiency of above 1.5, but the tank's hull weight is not more than that of the Chieftain (which had 380 mm steel armour according to British sources but a shorter hull and a lighter engine).
Also - depending on the timeframe - the TE of NATO's armour was worse than in some of your example. THS with a TE of 1.8 for example is according to Sebastion Balos in the TankNet thread about the Leclerc only possible due to newer manufacture techniques allowing much thicker HHS layers (and patents from France and Germany show that this techniques come from the early 1990s). Older NATO tanks had in best case THS with a TE/EM of ~1.5.

Regarding the armour weight a "rough estimation" shows that the weight of the Leopard 2 turret armour is possible only 50% of the volume (even less if you base your estimation on militarysta's RHAe-estimates and the mass efficiency of Burlington). That would mean that if the hull is similar made, the effective protection against KE would be less than 500 mm RHAe.

Btw: It is not possible to use HHS on the extremly sloped part of the glacis in the M1/Leopard 2, because HHS tends to be brittle, but the strongly sloped glacis is designed to riccochet enemy ammunition. The HHS would simply break and create much unnessecary spall. A more ductile (and thus more or less directly softer) steel makes more sense there. Paul Lakowski believed that the steel structure (turret and hull "case") is made of something like 350 HB steel on the M1 (which means the upper scale of RHA) - bojan or someone else posted a similar hardness value for the hull of the T-62 (and thus likely similar steel is used for the T-72).

IMHO the biggest drawback of Challenger 1 was that damn rifled gun. The penetration capabilities for a 120mm calliber were just pathetic.

I don't think that there can only be one single factor. The FCS was bad, the tank was unmotorized, ammunition storage was not optimal, engine too small, gun was outdated, TOGS and main sight were separated, the armour behind the driver's hatch guarantees a T-54 a one-shot kill. In many aspects the T-80B and the T-80U were better.

For the M1 the biggest drawback would be probably the lack of panoramic CIV, and somewhat strange decision to stick with 105mm and make trails of the new gun so long.

The early M1 had a deliberatly simplified FCS (also in performance), low gun and not much armour (given the description from the Armor magazine, Zaloga and Hunnicutt).

 

[Damian]

I don't think so. Armour protection is a result of weight and space. The glacis of the late T-72B/T-90 weighs more than 500 mm RHA. The small amount of bulging plates is insignificant IMO for protection against KE, so the armour can be seen as an array of spaced steel layers (of different hardness). So the weight equivalency will be above 1, depending on the exact hardness of the layers. The weight efficiency of the armour against shaped is only slightly better.
The hull armour of the M1 Abrams and Leopard 2 is - at least as far my own measurments and some other sources show - not thicker (or if it is thicker then less than 5 cm). But I do not see why there should be much more weight. The hull of the Leopard 2 and M1/M1IP/M1A1 does not seem to have large weight reserves, especially if the armour needs also to protect against shaped charges. Burlington-style armour might have a weight efficiency of above 1.5, but the tank's hull weight is not more than that of the Chieftain (which had 380 mm steel armour according to British sources but a shorter hull and a lighter engine).
Also - depending on the timeframe - the TE of NATO's armour was worse than in some of your example. THS with a TE of 1.8 for example is according to Sebastion Balos in the TankNet thread about the Leclerc only possible due to newer manufacture techniques allowing much thicker HHS layers (and patents from France and Germany show that this techniques come from the early 1990s). Older NATO tanks had in best case THS with a TE/EM of ~1.5.

It is not that easy, You needs to calculate a TE of each used material in the array and then combine it, the biggest problem is to determine exact compositions.

Same applies to the rest of your post. Especially that not much is known about these armors.

 

[Damian]

I used a combination of SHS/HHS, SiC and RHA.

I assumed that a array is 650mm thick with 50mm thick outerplate and 100mm thick backplate, which leaves 500mm thick composite array.

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) + 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) x 4 + 100mm RHA (1 TE vs KE, 1 TE vs CE) = 65-67/65mm RHAe vs KE/CE + 1,3mm RHAe vs CE + 65-67/65mm RHAe vs KE/CE + 48,5/75mm RHAe vs KE/CE + 12-12,5/12mm RHAe vs CE x 4 = 502-512/608mm RHAe vs KE/CE.

So:

65-67mm RHAe vs KE + 502-512mm RHAe vs KE + 100mm RHA vs KE = 667-679mm RHAe vs KE
65mm RHAe vs CE + 608mm RHAe vs CE + 100mm RHA vs CE = 773mm RHAe vs CE.

Seems to be resonable model for the M1 "beak", and effect will be even better if you replace AD-97 with something else.

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) + 10mm HHS + 50mm DU (1,5 TE vs KE, 1,5 TE vs CE) + 10mm SHS (1,2-1,25 TE vs KE, 1,2 vs CE) x 4 + 100mm RHA (1 TE vs KE, 1 TE vs CE) = 65-67/65mm RHAe vs KE/CE + 1,3mm RHAe vs CE + 65-67/65mm RHAe vs KE/CE + 75/75mm RHAe vs KE/CE + 12-12,5/12mm RHAe vs CE x 4 = 608-618/608mm RHAe vs KE/CE.

vs KE = 773-785mm
vs CE = 773mm

So everything depends on composition, and here is the field to think about.

PS. Although it is difficult, I do not have TE values for all possible material.

 

[Damian]

Ok I made also one more additional calculation for the M1's front hull armor.

We know that there are fuel tanks directly behind front armor right? Let's calculate only fuel, not fuel tanks bulkheads. We can assume tha the fuel volume in horizontal will be equivalent of 800mm (the fuel tanks are ~1,000mm long).

Diesel fuel TE is 0,15 ve KE and 0,55 vs CE.

So:

Option A (Without DU)

65-67mm RHAe vs KE + 502-512mm RHAe vs KE + 100mm RHA vs KE = 667-679mm RHAe vs KE + 0,15 x 800 = 120 = 787-799mm RHAe vs KE
65mm RHAe vs CE + 608mm RHAe vs CE + 100mm RHA vs CE = 773mm RHAe vs CE + 0,55 x 800 = 440 = 1,213mm RHAe vs CE.

Option B (With DU)

vs KE = 773-785mm + 120mm = 893-905mm RHAe vs KE
vs CE = 773mm + 440mm = 1,213mm RHAe vs CE

It seems that fuel tanks have serious impact on armor protection.

 

[methos]

Damian, I don't understand what you are trying to prove. I thought we already established that ceramic is only a minor component in NATO armour and not (like in your example) the main component.
Most people believe that Silicium carbide is not used in modern tank armour, because it costs about 7 times as much as Aluminium oxide (!). Ceramic armour also needs a backing and a ballistic/splinter foil to have mulit-hit capability... in case of MEXAS and other light/medium armor system the backing alone is thicker than the ceramic plates (reducing effective thickness efficiency). Paul Lakowski takes this in his Armor Basics into account by always including GRP or Kevlar in his wrong assumptions about Burlington armour. You do not and your example of how the armour could look does not have mulit-hit capability...

The DU array is ridiculous... why using DU in such a configuration, when it does not increase armour protection compared to steel layering of the same thickness or weight. Also the only TE value I saw for DU when it comes for protection against KE is 1.3 and not 1.5. The only case where we know how DU is used is the spaced DU armour array developed by the Brittons some time ago (where the TE vs KE is possibly less than 1 because of the space inbetween).

Outer and innermost layer of the armour are likely RHA - other types of steel cannot be used for structural elements.

I think we should take a look at known armour arrays. In case of the early T-64 hull and turret armour about/more than 50% of the armour volume was used for armour optimized for defeating shaped charges. In the Leopard 2 turret armour array posted by militarysta some time ago more than 50% of the armour volume is used for armour optimized for defeating shaped charges. In the side turret armour of the M1A1HA, which can be seen because the tank was damaged, more than 50% of the armour volume is used for armour optimized for defeating shaped charges. I think you can notice the pattern and I do not have to continue here. The T-72B from 1989 is insofar an exception because the main amount of anti-CE armour was replaced with ERA freeing space and weight for more anti-KE armour.
Now your suggested armour arrays (with or without DU) are completey different and noone of them provides resonable protection against shaped charges (which are much more likely to hit the lower hull, because ATGMs, RPGs, stand-off mines, etc. all are launched from much lower height than APFSDS). The fuel behind the armour would prevent a perforation of the crew comparment, but once the fuel is incinerated the crew has to leave the tank due to the heat (unless the want to have a toasted driver). To exactly prevent the need to abandon a tank after one non-penetrative hit the U.S. tank designers armoured the turret bustle with thicker (and heavier) composite armour than all other countries...

I think the hull armour should look similar to the turret side or turret front armour, meaning that likely more than 50% of the internal volume (so more than 300 mm for your value "650 mm thickness") are occupied by non-explosive reactive armour - be it sandwich plates or a spaced plate array mounted on coil springs.

 

[Damian]

What I proves is that within a certain array thickness, there is possible to achieve different protection levels.

Przeździecki wrote in one of his articles that British discovered that Burlington type armors can be "tuned" against certain threats. It probably means that if the whole armor array is semi modular, the armor composite filler itself is modular and you can try to optimize it against both threats. Now the question is how. I made some simplified models, but this models can be altered.

Option A (Without DU)

65-67mm RHAe vs KE + 502-512mm RHAe vs KE + 100mm RHA vs KE = 667-679mm RHAe vs KE + 0,15 x 800 = 120 = 787-799mm RHAe vs KE
65mm RHAe vs CE + 608mm RHAe vs CE + 100mm RHA vs CE = 773mm RHAe vs CE + 0,55 x 800 = 440 = 1,213mm RHAe vs CE.

Option B (With DU)

vs KE = 773-785mm + 120mm = 893-905mm RHAe vs KE
vs CE = 773mm + 440mm = 1,213mm RHAe vs CE

In above case, the Option A do not use SiC but AD-97. So there is plenty of possibilities.

A certain claim that something is is not possible, is just false, simply because we do not know the exact composition and design of the armor.

I think the hull armour should look similar to the turret side or turret front armour, meaning that likely more than 50% of the internal volume (so more than 300 mm for your value "650 mm thickness") are occupied by non-explosive reactive armour - be it sandwich plates or a spaced plate array mounted on coil springs.

Even if so I can later try to calculate it, though the problem is dynamic effect on the penetrator or shaped charge jet. The TE calculation threats such array still as passive armor because of simplification.