Main Battle Tanks and Armour Technology

[Kunal Biswas]

Damian is right abt things following:


1. Arjun Sight placement is a flaw inherited from Leo2a4.

2. Arjun side are partially armored, the photo are right.

3. Huge mantel requested by army is also a flaw..

Arjun MK-1 is India`s first tank, And have flaws just like any-other tank developed by any other Nation for first time..

As Evolution goes on these flaws will be rectified..

 

[pmaitra]

I agree with Damian on the sight and side armour.

I think GK has a valid point. If mantle is large, it covers a larger region in 3D space that encapsulates the rest of the turret. In other words, the 'penumbra' behind the mantle is larger. However, if the mantle was smaller, more of the 'penumbra' would be exposed and would require more armour. This is speaking of frontal assault.

Said that, it would be better to have a smaller mantle and well shielded sides than the current take-'em-head-on philosophy.

 

[methos]

First things first, we are talking about IS-2 with initial hull or IS-2 with later hull that offered better protection? IS-2 IMHO was better than Tiger 1 in that regard.

At the time the late model of the IS-2 was being produced the Germans stopped Tiger production and went with the Tiger II instead. The Tiger is not weaker armoured than the early IS-2, and the Tiger II is by far better armoured than the 1944 model IS-2.

IS-3 being comparable to King Tiger? IMHO better as a whole in terms of protection. Turret was allmost all around ~200mm thick if I remember correctly (need to check it) and front hull was well shaped.

1. The "pike-shaped" glacis proved to be a problem later in real warfare, because the welding seams could not hold so thick plates, i.e. when being hit the glacis sometimes "broke" into serveral pieces. At least this happened to Egypt IS-3 when they fought Isreali tanks. The solution for this would have been interlocked welding, as done by the Germans on Panther and Tiger II - which would be a total contradiction to the Soviet design doctrine because it would require huge amounts of time and workforce.
2. The IS-3s steel is even more brittle and cast, unless they Soviets did use better steel than in their IS-2s (which seems improbable).
3. The IS-3 did not have 200+ mm thick armour all around. Some sources I have seen claim that the armour at the side was sometimes 100 to 200 mm thick (i.e. partial as thick as the front), others claim that the armour was only 75 - 115 mm thick. It may be that the 200 mm figure refers to a heavily sloped part, like the upper sides, which merges seamlessly with the roof. For rear armour only figure I have seen was ~100 mm.

3) M60A1 was also penetrable but yet more armor gived it chances to survive, especialy at more extreme hit angles. I think Dejawolf made few years ago 3D model if M60A1 turret with armor estimates that takes in to account armor angle at respective angle, and it was impressive.

His estimate is based on his 3-D model. He made it, measured the angles and assumed that the armour has always the same thickness, which would be true for steel plates, but not for cast armour, which can be made more variable. Following this logic the Chieftain would have some 600 - 800 mm in the cheeks (because the turret slopes back) and the Leopard 1 would have a maximum armour thickness of 180 - 200 mm (Paul L. did this estimate based on the same logic in the SteelBeasts forum, ingnoring the fact that this would mean that the 50% lighter Leopard 1 turret with a heavier gun and more FCS equipment would offer as much (and partial even more) protection as the M48 turret.

 

[Damian]

I strongly support Damian here. More complicated and sophisticated does not mean better. T-34 is a legend, so is the Kalashnikov. Their biggest strength is simplicity.

It applies almost everywhere. Despite being several times more complicated, technologically advanced, and sophisticated than the Soyuz, the Space Shuttle is still a very inferior passenger space vehicle compared to the Soyuz.

Even in statistics and machine learning, there is a concept called Occam's Razor. Read a little about it. I have put the salient point below:

Yes but in the 1960's to 1980's Soviets manufactured more advanced and from mechanical point of view complicated tanks. Even these days T-72 will be mechanically more complex than Leopard 2 or M1 Abrams.

1. The "pike-shaped" glacis proved to be a problem later in real warfare, because the welding seams could not hold so thick plates, i.e. when being hit the glacis sometimes "broke" into serveral pieces. At least this happened to Egypt IS-3 when they fought Isreali tanks. The solution for this would have been interlocked welding, as done by the Germans on Panther and Tiger II - which would be a total contradiction to the Soviet design doctrine because it would require huge amounts of time and workforce.

It was not problem with the welding, as far as I remember and this was widely discussed few years ago on polish military forums, the main problem was turret placement that was too far to the front, making there much more stresses, and this was a problem.

3. The IS-3 did not have 200+ mm thick armour all around. Some sources I have seen claim that the armour at the side was sometimes 100 to 200 mm thick (i.e. partial as thick as the front), others claim that the armour was only 75 - 115 mm thick. It may be that the 200 mm figure refers to a heavily sloped part, like the upper sides, which merges seamlessly with the roof. For rear armour only figure I have seen was ~100 mm.

I should have somewhere thickness drawing, if I find I will post here. But turret have thicker armor near turret race ring and upper part being inclined was thinner.

His estimate is based on his 3-D model. He made it, measured the angles and assumed that the armour has always the same thickness, which would be true for steel plates, but not for cast armour, which can be made more variable. Following this logic the Chieftain would have some 600 - 800 mm in the cheeks (because the turret slopes back) and the Leopard 1 would have a maximum armour thickness of 180 - 200 mm (Paul L. did this estimate based on the same logic in the SteelBeasts forum, ingnoring the fact that this would mean that the 50% lighter Leopard 1 turret with a heavier gun and more FCS equipment would offer as much (and partial even more) protection as the M48 turret.

But they are right, everything depends on hit angle, for example cast turret of T-72B hit at 0 degrees angle at one point will have a thickness of ~1,000mm. As one of Russians which I talk said "madness of cast turrets".

I think GK has a valid point. If mantle is large, it covers a larger region in 3D space that encapsulates the rest of the turret. In other words, the 'penumbra' behind the mantle is larger. However, if the mantle was smaller, more of the 'penumbra' would be exposed and would require more armour. This is speaking of frontal assault.

Said that, it would be better to have a smaller mantle and well shielded sides than the current take-'em-head-on philosophy.

It works different way.

As I gave such example earlier:

We have two gun mantle armored masks, both have same weight and same thickness, but one is more width and one is more narrower. Which of these two will offer better protection? Ofcourse narrower, because with the same weight and thickness, being smaller means it have more dense protection.

It is specially important because gun mantle masks are not made from advanced composite armors where using of many materials with different properties and possible reactive elements can compensate this.

IMHO perfect size of gun mantle have Merkava tank series, then Challenger 1, M1 Abrams and South Korean K1/K1A1 and K2, oh and surprisingly Italian C1 Ariete.

 

[pmaitra]

Damian, I see what you are saying, and of course, there are always exceptions. In the same breath, M1A1 Abrams is better than T-72, even if you compare the Soviet T-72s and not the export versions of T-72.

Not saying that is by virtue of simplicity, but my point was simplicity should always be preferred if it gets the job done. In other words, pick a Honda over a BMW.

 

[Damian]

Damian, I see what you are saying, and of course, there are always exceptions. In the same breath, M1A1 Abrams is better than T-72, even if you compare the Soviet T-72s and not the export versions of T-72.

Not saying that is by virtue of simplicity, but my point was simplicity should always be preferred if it gets the job done. In other words, pick a Honda over a BMW.

Simplicity do not exclude being advanced in the same time.

Everything depends on choosen design solutions.

 

[methos]

But they are right, everything depends on hit angle, for example cast turret of T-72B hit at 0 degrees angle at one point will have a thickness of ~1,000mm. As one of Russians which I talk said "madness of cast turrets".

At which part? Taking a look at both the real T-72B turret and drawings of it I fail to see any place where 1,000 mm thick armour should be located unless you refer to the "overhang" on the sides which does not cover the crew compartment when being hit by 0°.
As far as the estimations are concerend: As I said the estimations for the Leopard 1 following the same logic are in conflict with the lower weight of the Leopard 1 turret compared to other turrets of which the armour thickness is more or less known. As you said regarding the IS-3 turret, cast armour can be made without having the same thickness at all parts. If we take a look at dejawolf's images we can see that he bases his estimates on two-plane slope... it might be possible that this is true, but at the same time it is also possible that the armour is variable thickness and therefore sloped in only one plane or not sloped (i.e. where the armour is more heavily sloped it is thinner) - so his estimations could be way exaggerated and currently there is no real reason to assume that it is not overestimated. The M60A2, which had a new turret which is also told to be more protective than the M60A1 turret has ~300-350 mm vertical armour. Paul Lakowski wrote in the same thread where dejawolf published his estimates a version based on Hilmes values which comes with two-plane slope to only 256 mm armour thickness (as claimed by several books). If the armour varies in the vertical the claimed values are ~20-30% to high, if the armour varies in the other plane, then the claimed values are ~50% to high. If it is variable in both planes, then 200-300 mm is about right.
Read the thread about the M60A1/A3 armour on Tanknet.

Damian, I see what you are saying, and of course, there are always exceptions. In the same breath, M1A1 Abrams is better than T-72, even if you compare the Soviet T-72s and not the export versions of T-72.

T-72B w/ Kontakt-1 ERA shouldn't be worse protected than the M1A1, with Kontakt-5 it should be comparable to the M1A1HA. Vant APFSDS should be comparable to M829 and Svinets/Lekalo are comparable to M829A1. Fuel efficiency is better on T-72, but top-speed of the M1 is better. FCS on T-72 is far worse, but T-80 has also comparable armour and similar FCS (excluding thermals).

 

[p2prada]

How is that logical for a production variant tank? Would the designers not even know that?

Precisely one of the reasons why the Army called the Arjun a vintage design.

 

[Damian]

Ok, I was searching in books I have IS-3 armor schemes, and I found it. This should be scheme made in factory, or from one of official documentations.


(IS-3)

(IS-2)

(PzKpfw. VI Ausf. H1/E)

(PzKpfw. VI Ausf. B)

 

[Damian]

And here something newer.


(Chieftain, I think this is Mk1 or some other earlier variants with thinner armor)


(M48)


(M60A1, here it is still a prototype stage, serial production vehicle had thicker armor)


(Leopard 1)

 

[Damian]

(AMX-30)


(T-54, one of the early variants)


(MBT/KPz-70)

 

[methos]

The image for the AMX-30 is wrong. According to Western books (French, German, British) the armour is max 81 mm LOS, i.e. the angles shown are correct, but it seems to show the LOS thickness instead of the real armour thickness for the front at least.

Tiger I turret armour is more complex. Of the turret front roughly 50% consists of heavily sloped parts (turret walls and turret roof), which will simply deflect AP (and likely also APDS) rounds. The rest of the turret has variable thickness from 100 to 150 mm. The gun mounting/mask/mantlet on the turret front covers nearly half of the turret and is 135 mm thick, the armour around the MG is 150 mm thick. Similar things can be said about the Tiger II turret, which also has strongly sloped side walls and a strongly sloped roof, with a large portion of the front plate being covered by the gun mask.

 

[Damian]

In case of Tiger 1, gun mantle mask is also front turret armor, because behind gun mantle mask there is no turret front plate. Similiar situation should be for any German and probably most other tanks of WWII.

 

[Godless-Kafir]

Precisely one of the reasons why the Army called the Arjun a vintage design.

When did the army call it a Vintage design? How could a Vintage tank do better than T-90? Also how long can it take to fortify the side, it has already been done on the Mark-2. The NERA or ERA is going to be mounted there.

 

[Damian]

How could a Vintage tank do better than T-90?

How do You know that in reality it was better than T-90? If I would be You I would be more carefull with beliving in official statements, especially that the whole tests and Arjun vs T-90 is a political shit hole.

Also how long can it take to fortify the side, it has already been done on the Mark-2. The NERA or ERA is going to be mounted there.

Arjun Mk2, or at least that graphic showing it do not have ERA over this weakened turret side, take a closer look, in place of old storage box there is a new type storage box, and ERA cassettes are placed over currently existing composite armor cavieties.

IMHO if tank have semi modular turret armor, then I would just weld in that place additional steel plates to create composite armor cavity and then place there composite inserts.

 

[Kunal Biswas]

How do You know that in reality it was better than T-90? If I would be You I would be more carefull with beliving in official statements, especially that the whole tests and Arjun vs T-90 is a political shit hole..

In that scene one can also say ' Arjun basing ' from last 20years or so was a Political and Arm dealers -PR..

 

[Damian]

Of course, the whole situation is merely political one.

India have ambitions to have it's own tank, and ok I understand that, I even support that (this is a good thing) but...

Honestly, India reminds me Soviet Union in this subject, we have here a state owned organization responsible for arms development, and as allways in such situation, this organization have "friends" in goverment. And because we have here a big pile of money and prestige, nobody will care about how good product a is from product b, but product a can be favorized because of mentioned reasons.

Still everything would be ok if someone from top would admit that designers are still learning of how to design a tank and initially it can be flawed design yet nececary to learn how to properly design a tank. But nobody do that, to the contrary, everyones start to celebrate, we have these silly statements about "best tank" etc.

And this is a dangerous situation, because armed forces due to fact that they are under civilian control (means politicians) and that civilian control also is owner of product a design bureau, will obviously force military to buy product a.

Of course in such situation someone could say that why spend money on fielding something that is not nececary better and not nececary needed? So who would even bother with transparency to discuss how to upgrade tank, how to eliminate problems etc.

Nobody will bother because why? And this is a real problem, if India will not start to make competitions to choose weapon systems nothing will change, because not the best possible solution could be choose by military, but the solution forced by politicians... preferbly something made by state owned company or design bureau.

If DRDO would have a competition with some other companys, for example GDLS, KMW/Rhinemetall, Nexter or even UVZ, then DRDO would be forced to do thing good, on time. But no such thing happend. No, even after T-90S induction DRDO was promised that Arun will be fielded, so who even cared?

And many countries face the same problem, to be honest in my country we have very similiar problems, difficult to solve, but it will be sooner or later nececity.

 

[p2prada]

When did the army call it a Vintage design?

Before induction.

How could a Vintage tank do better than T-90?

It never did. While Russians claimed the T-90 was superior to the Arjun. DRDO never claimed the same. There is not a single news article which claims the Arjun is better than the T-90.

Army bought the T-90 after Arjun trials were complete in 1998-99.

Also how long can it take to fortify the side, it has already been done on the Mark-2. The NERA or ERA is going to be mounted there.

Is this question for me? Anyway we will see the tank in June.

 

[p2prada]

Nobody will bother because why?

The Army does. They demonstrated that they don't cave easily to pressure by inducting the T-90s.

Btw, we just had this interview with the DRDO chief who said that if DRDO is not able to deliver then the MoD and Armed Forces start pressurizing DRDO to allow import of the specific weapons system. That tacitly means DRDO allowed the import of T-90 because of their non performance with Arjun.

The same thing happened after Kaveri engine failed. Once IAF realized the future for LCA is bleak, they launched a tender for Mirage-2000 type aircraft quite quickly.

This obviously means DRDO never had any issue with induction of T-90s. But they want the Army to buy 500 tanks to break even on the program(no profit or loss). If the army caves to pressure, we will end up being a two tank force.

Currently we aren't importing ABM systems like Patriot, S-400, David's Sling or Arrow because DRDO is confident of delivering the Indian BMD system in time. If the AAD fails, then it will open the doors for foreign imports.

 

[Kunal Biswas]

Of course, the whole situation is merely political one.

India have ambitions to have it's own tank, and ok I understand that, I even support that (this is a good thing) but...

No, Its not in India..

Coz here arms dealer rules the MOD, Mostly, you don't get kick backs in Indigenous program..


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Besides, Arjun is deign as per army demands there is no reason army would speak such nonsense when Chief himself praise it..