Main Battle Tanks and Armour Technology

[militarysta]

Leopard-2 turret whit NPzK140mm L48 on Leopard-2 T19 prototype photo from 1992.

 

[darklabor]

Leclerc have weak PR and it's only real disadvantage of this greate tank. And Vartisla fuel compsumption - like in AGT-1500, but apar that Leclerc is very, very good tank...

I can't remember what PR stands for. Could you give me a hint?

I heard that there were problems with Leclerc, even with software. There were some serious accidents.

I think I see what you're talking about.
In fact there had been a problem of short circuit in some electronical box linked to the FCS. That made some serious troubles. By exemple, there was some turret movements against the user's commands. In the end the tank fleet was seriously inspected to see what happened. There was some defecting sealings and moisture made short circuits on the electronical boards. New sealings are now applied.

 

[Damian]

I think I see what you're talking about.
In fact there had been a problem of short circuit in some electronical box linked to the FCS. That made some serious troubles. By exemple, there was some turret movements against the user's commands. In the end the tank fleet was seriously inspected to see what happened. There was some defecting sealings and moisture made short circuits on the electronical boards. New sealings are now applied.

Yeah, I got information from a Polish imigrant that was a tank crew member in US Army, he got some trips around the world to US allies and had a close look on different tanks used by NATO. When he talked with French tank crews, they said to him that indeed there were problems with unexpected turret movements that lead to some accidents with wounded people included.

It is interesting that there were such problems with a tank, perhaps too much pressure lead to inducting vehicle too quickly.

 

[darklabor]

Yeah, I got information from a Polish imigrant that was a tank crew member in US Army, he got some trips around the world to US allies and had a close look on different tanks used by NATO. When he talked with French tank crews, they said to him that indeed there were problems with unexpected turret movements that lead to some accidents with wounded people included.

It is interesting that there were such problems with a tank, perhaps too much pressure lead to inducting vehicle too quickly.

Can't tell...

From what I heard some incidents where claimed to be caused by the tank. In fact there had been bad manipulations as well.
By exemple a gunner manipulated the autoloader in emergency mode. He broke the ramming device by rotating the ammunitions while it was out. In the end he claimed it wasn't his fault and accused the normal mode to cause this.

Same thing tend to happen with the VBCI as far as I heard...
A driver made a 180° turn (that is a caracteristic of the running gear) on a slope. The IFV went on his back and people said that manoeuver was forbidden due to the risk of flipping over.

 

[Damian]

It is possible to rotate autoloader ammunition cassettes during loading cycle when ramming device is extracted? IMHO there should be sort of blockade to prevent such.... actions.

 

[darklabor]

It is possible to rotate autoloader ammunition cassettes during loading cycle when ramming device is extracted? IMHO there should be sort of blockade to prevent such.... actions.

Well, it's in emergency mode, so there is no control by electronical components, it's just pure actuation.
The Leclerc got something like 4 modes wich correspond to different levels of computer controls. Normal mode is the most controlled and emergency isn't controlled at all.

 

[Damian]

But afterall there should be some sort of mechanical blockade for rotation mechanism.

 

[darklabor]

But afterall there should be some sort of mechanical blockade for rotation mechanism.

Why not. But it just increase the complexity of the overall, therefor the price and the risk to increase the weight of the components.
After all it's just common sens not to rotate the autoloader while having the ramming mechanism out.

 

[Damian]

Reasonable argument.

 

[Damian]

newvid

Video in this link shows Meggitt company Compact Autoloader designed for M1 Abrams. Autoloader hold 34 rounds (for comparision the AZ autoloader in T-72/T-90 series as well as Al Khalid and Chinese tanks hold 22 rounds, MZ autoloader in T-64, T-80 and T-84 holds 28 rounds and autoloader based on the one used in Leclerc holds 22 rounds, used also in South Korean K2 and Japanese Type 90 and probably also Type 10), fits inside the currently existing space inside turret bustle, is completely isolated from crew, and still permitts to have a 4th crewmember that can now perform other tasks than loading the main gun.

Thanks to @militarysta for finding it.

 

[Damian]

Seems to be a different proposal for USMC M1A1 ILWS (Improved Loaders Weapon Station).

 

[militarysta]

Leopard-2A4 interior on draws. Part of leo-2 manuals.
Sorry for polish descripsion.

Tank Commander - Front:

rear:

Gunner:

Loader front:

Loader rear:

For polish "three letters" services (ABW, WSI, etc): Found on polish PWM forum - i'd never post part of official manuals.
(znaleźione na forum PWM - nie moje hostowanie.)

 

[Damian]

RUAG introduces a new Leopard 2 A4 armor upgrade at IAV 2013 International Armoured Vehicles

The options open to those customers researching the international market for solutions aimed at either replacing the existing A4 MBT fleet, or upgrading are varied. They either replace with surplus models (A5 & A6) or embark on a Mid Life Upgrade programme of the A4 version. However, when considering protection some factors are indisputable.

The Leopard 2 A5 possesses the same protection levels as the A6 version. This armour is a significant improvement on the Leopard A4 version. However, in improving the passive protection in these two versions the result has been a significant increase in the vehicle weight, which affects the torsion bars, tracks and suspension system. The Leopard 2 A5 has been in service since 1995 and Leopard 2 A6 (based on Leopard 2 A5`s) since 2001. Therefore, the platforms in comparison with Leopard 2 A4 tanks have been under increased stress over an extensive period.

With only the front protection modules mounted, RUAG Defence is able to improve the overall protection of the turret crew compartment, thus exceeding the protection available on the Leopard 2 A5/A6.

[/URL]

Interesting upgrade proposal.

 

[methos]

From their brochure:

 

[Damian]

Very interesting is this sort of slat cage over main gun sight. It definetely improves protection in this area, readucin the weak zone.

 

[STGN]

I have a question I have been pondering:
Why is it that many rate the early Leo 2s tanks as having much better armor against KE than the early M1, the tanks weigh the same, "recent" photos of the interior from Iraq war and production of the Abrams show that the armor was just as thick or slightly thicker ~84cm LOS in the front turret. Now the Abrams does have thicker side turret armor but the Leopard2 has several heavier components.

Tank:	M1 Abrams	Leopard 2A4
Weight:	55020 Kg, MLC 60	55125 Kg, MLC 60
Gun system:	M68A1 105mm: 1130Kg	L44 120mm: ~1900Kg
Engine:	AGT1500: 1,134Kg+ ~1900kg fuel	MTU873: 2200Kg+ ~1200kg fuel
Road wheels:	Aluminium 63.5cm dia	Steel 70cm dia

Yet M1 front turret armor is rated around 400mm(Zaloga has published different numbers 350-400-470(USSR esti.)) while Leo2 receives around 550mm(A1-A3(USSR apparently gave it 400-450)) and upwards 690mm(A4) Link.
Seems kinda strange to me where the Germans really that much better?
STGN

 

[Damian]

@STGN

It is because people too much believe in the publicated informations for general public. The fact is that thanks to recent research of Paweł Przeździecki we know that research and development program codenamed "Burlington" did not ended with development of a one single armor type, but the whole family that differed in performance, weight etc. And this is only for UK, USA developed their own subvariants under codename "Starflower" and we know that Ballistic Research Laboratory tested at least two variants codenamed BRL-1 and BRL-2, Przeździecki assumed that BRL-1 could be analog to the armor configuration used in basic M1, while BRL-2 was analog to M1IP and M1A1 protection. But not much is known really.

So in fact all these estimations are mostly fairy tales, based on informations that original requirement for M1 was to be protected against 115mm APFSDS, and this again rather proves that most people have limited knowledge about requirements procedures. Requirements documents nature is that these requirements are fluid, and we do not know when requirement about 115mm APFSDS was estabilished and if it was changed, and if it was changed when it was changed.

USA thanks to USMLM and contacts with British BRIXMIS as well as Israeli intelligence from recent Arab-Israeli wars, definetely had knowledge about increasing firepower of Soviet Tanks. And you do not design a vehicle protection only against former and present threats, but also against predicted future threats.

So I would not put too much attention to these estimations.

http://www.wceo.wp.mil.pl/plik/file/WBBH/PH-W/PHW_4.pdf

Here is a link to Paweł Przeździecki article about "Chobham" armor development. Page 106 in Acrobat Reader, you probably do not know Polish so translator is nececary.

Przeździecki albo claims that Germans received results of "Burlington" program and it is probable that Leopard 2 also uses one of the "Burlington" family armors.

So in the end we do not know the exact composition of armors used by both vehicles, and we can assume that in terms of quality they can be comparable.

 

[Damian]

@STGN BTW, one more important thing. Przeździecki writes in his work.

W konfiguracji z przełomu lat sześćdziesiątych i siedemdziesiątych, w konfrontacji
z amunicjÄ… kumulacyjnÄ… "žBurlington" byÅ‚ od 2 do 3 razy skuteczniejszy od jednorodnego
pancerza stalowego o tej samej masie – przy zbliżonej odpornoÅ›ci przeciwko pociskom
kinetycznym.

Translations: In configuration from between 1960's and 1970's, against shaped charge warheads, "Burlington" was from 2 to 3 times more effective then homogeneus steel armor of the same weight - with similiar protection against kinetic energy projectiles.

Of course effectiveness was increasing with further research, it is really curious subject of scientific research, especially that up to this day we do not know much about "Burlington".

Podczas jednej
z rund trójstronnych testów uzbrojenia pocisk APFSDS wystrzelony z niemieckiej gładkolufowej
"žsto dwudziestki" pokonaÅ‚ jeden z wariantów "žpancerza Chobham" przy prÄ™dkoÅ›ci
uderzenia symulującej trafienie z dystansu 6000m. Opracowana cięższa wersja osłony była
jednak przebijana dopiero z 200m.

Translation: During one of the trilateral tests of armament, APFSDS projectile fired from German smoothbore "120mm" defeated one of "Chobham" armor variants with velocity simulating a hit from 6,000m. Developed heavier version of the armor, was however perforated only from 200m.

W 1978 r. brytyjski pancerz specjalny został poddany bliżej nieokreślonym zmianom,
związanym zapewne z adaptacją na potrzeby programu MBT-80. W odróżnieniu od
"žkonwencjonalnego", pancerz zmodyfikowany byÅ‚ okreÅ›lany jako "žulepszony" lub "žnowy"
Chobham". W miarÄ™ napÅ‚ywu informacji o sowieckich czoÅ‚gach T-64 i T-72, uzbrojonych
w armaty kalibru 125 mm, wzrosły wymagania odporności: do poziomu 480 mm przeciwko
pociskom APFSDS oraz ok. 600 mm przeciwko HEAT. Tę pierwszą wartość wkrótce
podniesiono do poziomu 540 mm RHA. Efektywność masowa nowych odmian osÅ‚ony wzrosÅ‚a do 1,3–1,5 przeciwko amunicji kinetycznej i do ponad 3 przeciwko gÅ‚owicom kumulacyjnym.

Translation: In 1978 british special armor, had been put in to unspecified modification, probably connected with adaptation for MBT-80 program. Contrary to the "conventional", modified armor had been called as "improved" or "new" "Chobham". When new informations came about Soviet T-64 and T-72 tanks, armed with 125mm guns, requirements for protection increased: to 480mm against APFSDS projectiles and circa 600mm against HEAT. The first value had been soon increased to 540mm RHA. Weight efficency of these new variants increased to 1,3-1,5 times against kinetic energy ammunition and to 3 times against shaped charge warheads.

 

[methos]

I have a question I have been pondering:
Why is it that many rate the early Leo 2s tanks as having much better armor against KE than the early M1, the tanks weigh the same, "recent" photos of the interior from Iraq war and production of the Abrams show that the armor was just as thick or slightly thicker ~84cm LOS in the front turret. Now the Abrams does have thicker side turret armor but the Leopard2 has several heavier components.

Yet M1 front turret armor is rated around 400mm(Zaloga has published different numbers 350-400-470(USSR esti.)) while Leo2 receives around 550mm(A1-A3(USSR apparently gave it 400-450)) and upwards 690mm(A4) Link.
Seems kinda strange to me where the Germans really that much better?
STGN

That the original M1 is less protected than the Leopard 2 is a very simply logical conclusion. It is simply the result of the comletely different conception of the tanks.
If you compare the hulls of both tanks, you will notice that both have about the same height, but the Leopard 2 has more ground clearance. If you look at the hulls without the side skirts, the Leopard 2's hull is 3,420 mm wide and 7,570 mm long, while the M1's is 3,480 mm wide and 7,916 mm long.
When it comes to the turret it is very similiar: The M1's turret is wider and longer, while the height from turret ring to turret roof is nearly the same. The M1 simply has a greater volume and a much greater surface than the Leopard 2, so it has to have more armour weight for reaching the same level of armour protection.
But there is also something to consider: the M1 has a kind of unique turret design. While all other NATO tanks have thick composite armour at the turret sides over the crew compartment, but the turret bustle is only protected by thin homogenous or spaced armour, the M1 Abrams has thick composite armour at the sides of the crew compartment and the turret bustle (which means about twice (!) as much side turret armour as the Leopard 2 without any gain in crew protection). The reason for this is the huge amount of ammunition stored in the bustle - while other tanks like the Challenger 1 & 2, the Leopard 2 and Leclerc store a considerable amount of ammunition in the hull, the M1A1 and M1A2 store only six 120 mm rounds in the hull - once the turret bustle is penetrated the M1 tank is a mission kill!

The original M1 produced from 1980 to 1984 also featured the "short turret" with thinner armour (according to Zaloga the armour was thickened from M1 to M1IP/M1A1 by about 9 inches). Russian estimates put the original armour thickness at about 600 mm, while an U.S. book claim that it is two feet thick and wikipedia says it is ~650 mm thick.

As far as the component weight is concerenced: Not all parts of the Leopard 2 are heavier and it is not as simple as shown by you.
For example look at the weight difference of the Leopard 2's powerpack and the M1's powerpack (figures by Rolf Hilmes):
If you compare only the MB 873 to the AGT-1500C the M1's powerpack is 71% lighter.
If you compare the complete powerpack (including transmission etc.) of the Leopard 2 with the complete powerpack of the M1, the later is 51% lighter.
If you compare the complete powerpack and the nominal fuel load of the Leopard 2 with the complete powerpack and nominal fuel load of the M1, the later is only 11% lighter.

What Rolf Hilmes does not provide is the weight of the fuel tanks; 1,200 l are much easier to store than 1,900 l - how much did that affect weight? I have seen different values for military class fuel tanks but unluckily none for thrid generation tanks: it is possible and very probable that the weight difference is smaller than 5% in the end.
Then several components of the Leopard 2 are lighter - for example the 42 rounds 120 mm ammunition (1/3 HEAT-Frag-FS (23 kg) and 2/3 APFSDS (19 kg)) will weigh less than 55 rounds 105 mm ammunition (18-19 kg APFSDS, 22 kg HEAT-FS). The PERI R17 weighs less than the M1's commander cuppola and the coaxial armament (and the ammunition for this) also weighs less. There are many different values, without knowing most of them speaking about the internal systems is not very helpful.

As Damian said - even though he speaks of "fairy tales" (because he is a big fan of the Abrams) - the original requirement for the M1's armour protection was to resist 115 mm APFSDS from 800 m distance and to resist shaped charges with a diameter of 127 mm. He is correct when saying that we don't know if the requirements for armour protection were changed, but this is no proper reason to say that the M1 is better protected than that. Let me show you why I think that the armour protection requirements weren't increased:
According to Hunnicutt the weight requirements were made at the same time as the previously mentioned protection requirement. However the weight requirement wasn't changed a single time (because the values given there are the same as used on production M1) - so where should the increased protection come? According to Hunnicutt the reason why the M1 ended up with Burlington armour is that it was the only type of armour fulfilling the protection requirement without exceeding the weight limit. The M1 also was superseded by the M1IP and the M1A1 - both having thicker and heavier armour. Why would they increase the amount of armour, if the previously armour was enough to resist current and future threats?

 

[Damian]

@methos, I have doubts, I mean M1 was definetely not better protected than Leopard 2 at a time when both were inducted in to service, IMHO protection was comparable, in fact M1 had better protected hull, and turrets had similiar protection.

Also remember that difference in turrets internal volume came from the fact that M1's turret have more sloped armor, and the fact that contrary to Leopard 2, M1 have frontal turret armor sloped in, I don't know if this will be correct, sloped in 2 dimensions, while Leo2 have it sloped only in one dimension., so actually at the turret roof, internal volume is probably comparable and in M1 due to sloped armor it increases at the bottom, on the race ring level.

As for protection, it comes from much more than just simple vehicle size, internal volume etc. There are also such issues as materials, armor working mechanism etc.

What is important to note is that British designers were provided with informations about FRG armor developments and in their opinion, none were as good as Burlington. Przeździecki assumed that Germans then adopted Burlington instead of domestic designs, however I know that you supports theory that Leopard 2 received armor developed in Germany not Burlington, if this would be truth, then according to British scientists, these armor were not at the same level of offered protection compared to Burlington. In such case American and later British claims might be true. But only if such scenario is truth, I do not say it is, simply I don't know.

PS. M1 turret is not unique, Leclerc turret also have composite armor protection over turret bustle side surfaces.

And about weight, you also should first consider if we weight "dry" or combat weight, the latter is allways bigger.

As for the armor thickness, these are still only estimations, as far as I remember, @STGN made accurate 3d model of the M1, and had different values for both M1 and M1A1, bigger than these mostly provided.

BTW there are also issues with Leopard 2 weight, for all variants from A1 to A4, have provided weight data of 55 metric tons, then we should assume that tank didn't had improved armor all that time? It would be nonsense, so or the weight data is wrong for earlier Leopard 2's (data for A4's seems to be correct as it is also confirmed by Polish Army), or the weight is not decisie factor of vehicle protection levels.