Leopard-2A0-A4 armor protection estimation

by Jaroslaw (Militarysta)

Gun mantled mask area

Turret armor left side (the loader)

Turret armor right side (the tank commander and gunner)

Turret sides on crew compartment area

Turret bustle

Turret roof armor

The hull frontal armor

Hull sides

The psychical thickens of the armor summary

The protection of whole tank can be describe in 3 aspects:

• Physical thickness of the armor;
• Integrity of the armor protection  and weak zones placement for tank for 0-30 degree from longitude axis; 
• Know special armor features and possibility to protect against KE munitions and CE munitions.

It's important to notice that Leopard-2 was developed as child of the many compromises - and some solutions judge now as bad - where developed in 1970's  to achieve better fire power (placement EMES-15 main sight in gap in frontal armor to simplicity optics and  thermal camera in main sight) or to achieve better susceptibility to service and repairs  - for example huge gun mantled mask was developed to achieve possibility to replace whole tank gun on battlefield without removal turret from chassis. 

In the breakthrough of the 1980s and 1990s when some solutions in Leopard-2A4 stars to be bad in term of armor protection (against suspected new Soviet anti-tank weapons) program KWS was started and deep modernization to 2A5 level was introduced when most questionable problems whit armor integrity where solved (improvement).

1) Psychical thickness of the tank armor:

Gun mantled mask area

Gun mantled mask in Leopard-2A4 is 420mm (42cm) thick and it has multilayered build. It's weight is equal 620kg. After the gun mantled mask is placed gun mounted frame (the wedge in German) made from thick light alloy metal. Those  frame is belted by thick metal plates which are making roof armor and bottom of the turret. Sides are cover by thick RHA plates which are making pins to fixed gun and gun mantled mask in one point in turret.

Whole area looks like this:

In fact whole armor layout in gun mantled mask area consist:

420mm armor block + 240mm light alloys mounted frame for gun + around mounted points between 80 and (mostly) ~230mm RHA metal plates. Thanks for this solution whole gun mantled mask area where protected well against early 1980s APFSDS and HEAT munitions penetration this area by 3BM15 or early BK-15 round was rather  questionable, and low possible to achieve. Leopard-2A4 gun mantled mask was immune against BMP-1 main armament 2A28 Grom low pressure gun whit HEAT rounds, and Maliutka ATGM.

Turret armor left side (the loader)

Physical thickness of the loaders turret part frontal armor is incredible (in the end of the 1970s) 860mm LOS. Armor back plate (metal plate ending whole special armor cavity) is made from 60mm RHA plate made from high hardness steel, frontal plate is probably the same thick. Between them is cavity (circa 740mm) for special armor module. This special armor module can by quickly replaced by cutting upper (roof) plate and change whole module. Similar process takes in 1991 in M1 Abrams case circa 30 min for one module (one box whit special armor module inside). 

Such big thickness was necessary due to Burlington style special armor features -this kind of the armor needs a lot of space. 860mm LOS thickness was the biggest on whole world until M1A1 went in to service in the end of the 1980s.

Turret armor right side (the tank commander and gunner)

The tank commander is protected by 660mm thick special armor block in front of his face. Now this area (behind EMES-15 main sight optics block) is consist as weak area but in almost whole 1980s is hard to agree with such statement 660mm LOS is space bigger then in most  tank's in  those era (except M1 Abrams) and should allow (by using more heavy armor components) to achieve similar  to the left side (loaders) protection.

Thickness of the armor in front of the gunner position is the same as on the left turret side so 860mm but whit different layout: the first armor cavity gap for EMES-15 and WBG-X components the second armor cavity. So whole thickens is close to 1100 mm (110cm) including this gap.

Turret sides on crew compartment area

Crew compartment turret sides are protected by 310 mm thick armor, so for 30 degree from turret longitude axis it's give almost 620mm LOS protection what was pretty big value in whole 1980s. Now such value seems to be not enough and Leopard-2A5 have NERA modules on turret sides, and almost all available Leopard-2A4 modernizations consists additional armor module for better protection of this area which doubled it's thickness. 

Turret bustle

Whole turret bustle after crew compartment is protected only by simple RHA armor. This solution was forced by weight reasons. It's the biggest weak area for whole Leopard-2 tank -and almost impossible to fixed even now. Partially it's cover by tactics of tank using front toward enemy, but in exist now non conventional warfare whole Leopard-2 turret bustle seems to be significant weakness, unable to cover without Active Protection Systems (like KAZ Drozd, or Trophy or AMAP-ADS).

Ammo rack in Leopard-2A4 bustle (whit blow out plate of course) is cover by circa 80mm thick armor so for 30 degree it's 160mm thick. Turret bustle rear is cover by only 25mm thick RHA plate:

Turret roof armor:

Leopard-2A4 turret roof armor is separated on PERI- loaders periscope line. The frontal part of roof is made by probably (author is not sure) 70 mm thick RHA  plate slopped on 7. degree so 580mm thick. It was (as in hull glacis plate case) more then enough in whole 1980s. But second part is probably only 30mm thick. This part was really vulnerable on small artillery bomblets or cluster munitions, and this part in all Leopard-2 modernization during KWS program was seriously improvement.

The hull frontal armor

Hull frontal armor is protected by 640 mm LOS thick special armor module. Only in it's the lower part it have smaller thickness circa 400 mm . Such value was more then enough to achieve significant protection in 1980s, but in 1990s all Leopard-2 modernization consist (except German ones) additional NERA armor to protect frontal hull armor.

Upper glacis plate is 40mm thick and slopped at 7 degree (so 320 mm RHA). Such slopped and height hardness RHA plates was more the enough against 1980s APFSDS ammo and imperfect HEAT warhead igniters (detonators) due to rebound. But introduce in 1990s long-rods and improved igniters in HEAT warhead forced cover this area in almost all Leopard-2 modernization (except German ones) by thick NERA modules (Leopard-2A5DK, Strv.122, Leopard-2A6E/HEL, etc).

The driver hatch is 30mm thick:

and it's construction was imperfect whole hatch was vulnerable  on 30mm gun fire and small AT warhead so in Leopard-2A5 whole construction was totally change. The driver hatch is second biggest Leopard-2 weakness.

Hull sides

Leopard-2A4 hull sides consist 3 thickness(!).

Driver right arm is protected (near hatch area) by 80mm thick RHA plate -but only there.

Hull armor on crew compartment height is 50mm thick, in suspension area it's 25mm.

Hull rear is protected by 25mm RHA plates.

It's important to notice that above track Leopard-2A4 sides are protected by multi spaced armor consist by: external 25mm RHA plate circa 580mm thick fuel tank 50mm hull armor.

According to Israeli the Merkava tank developers 70mm of the fuel is equal to 10mm armor plates. So 580mm fuel act (vs HEAT warhead) as 80mm armor plate. Such layout was better in 30 degree conditions and gives probably enough layers and space to stop older RPG-7 grenades.

Under the fuel tank Leopard-2A4 sides are protected  by 50mm hull armor and 12mm light side skirts:

Hull ammo rack is cover from sides not only by 50mm thick hull side but also by heavy ballistic skirts 110 mm thick:

Each module weight more then 110kg, and consist two 50mm RHA plates separated by air gap.

So protection of sides under track line is 100mm RHA plates + space + 50mm hull armor.

For 30 degree it's give 200mm plates + space + 100mm hull armor. What including high hardness plates was enough in late 1970 to stop most light AT weapons and older gun rounds.

Now such protection is not enough ands almost all asymmetric warfare leopard-2 modernization consist new much thicker heavy ballistic skirts for almost whole hull sides.

                                                  The psychical thickens of the armor summary:

Integrity of the amour protection  and weak zones placement for tank for 0-30 degree from longitude axis

In Leopard-2A4 armour integrity is secondary factor the absolutely priority for developers had firepower, mobility and   susceptibility to service and repairs. Many of the Leopard-2 solutions are given as the example of the weak spots or bad armor integrity. For the most often noticed flaws we can included:

enormous gun mantled mask

armor block after EMES-15 sight vision block

lack special armor for turret bustle

In fact ONLY the last one example can be describe as seriously weak spot but only for sides or 15-30 degree from longitude axis. Leopard-2 developers decide for such solution for weight reason.

Armor block after main sight EMES-15 optics block can't be described as weak spot for whole 1980s. Why? Because 660mm LOS thickness is exactly the same value as frontal turret armor most of 1980s tanks:

In T-64A and T-64B frontal turret armor is maximum 485- 496 mm thick (LOS)

(source: http://btvt.narod.ru/raznoe/bulat-leo2.files/image011.jpg) it's still smaller value then 660mm armor.

In T-80B case for frontal LOS it's between 560 and 640mm (for 30 degree 530 mm )

I case T-80U turret armor is mostly ~ 600mm LOS

(source: http://btvt.narod.ru/raznoe/bulat-leo2.files/image011.jpg http://btvt.narod.ru/4/bars_leopard/80-1.jpg)

What again is smaller value.

Frontal T-72B armor is between 600 and 750mm and for 30 degree it's 600-680mm what still is the same value as 660mm LOS in Leopard-2.

For such reason 660mm thick armor block in Leopard-2A4 can't be describe as weak spot in compare whit soviet tanks 500-600- 680 mm thickness.

In breakthrough of the 1980s and 1990s when new ATGMs and APFSDS rounds become available and new, improved soviet tanks turrets become available (Ob.187, Ob.478BE, etc) it's starts to be clear that indeed in 1990s those area will be serious flaw. For that reason frontal armor was completely changed in KWS program, and now left and right armor is the same in armor thickness (~860mm).

Gun mantled mask in Leopard-2 is 93cm width what is comparable whit soviet tanks mostly cast  gun mounted points and coaxial MG areas this area in soviet tank is circa 83-86cm width.

So both values are comparable.

For such reasons in whole 1980s and early 1990s (before much better Ob.478BE and OB.188A1) weak spots for Leopard-2A4 and most Soviet Tanks where comparable:

and both weak areas can be compare on one picture:

Of course in compare whit T-80UD Leopard-2A4 seems to have much worse conditions.

In fact Leopard-2A4 turret can be compare in both aspects: armor integrity, weak areas, and hazardous factor (ammunition, oil pumps, etc) on one picture:

 Know special armor features and possibility to protect against KE monitions and CE munitions

In special armor case we don't known details. Thanks to Pawel Przezdziecki reseerches in UK we can describe some general burlington-style armor features:

British armour was build as some kind of "bulkhead armor" whit space flitted by layers made (those layers) as sandwich - two thin steel layers and between them non metallic layer

In configuration from at the turn of 1960/1970, against SC warhead "Burlinghton" was 2-3times better then monolithic steel armour whit the same mass, and had (Burlinghton armour-milit.) similar resistance (as those monolithic steel armour ) against kinetic energy rounds.

The mass efficiency of the new armour variants (Burlinghton -milit) increased to 1.3-1.5 against KE and do more then 3 against SC warhead (HEAT) This part is about Burlinghton from circa 1978r.

Translate part 1:
In the second half of the seventies began to pay more attention to the protection against kinetic munitions. "Biscuits" (Burlinhton-milit.) developed for Chieftain mk 5/2 was able to stop 105 mm APDS shot virtually "with relief" (0m distance) or 120 mm APDS from a distance
1200-1300m. In 1975 in the United States , "Americanized" armor was successfully tested against 152 mm XM578 APFSDS munition and HEAT projectiles (unspecified caliber) which represented the expected level of the warhed in 1980s'. The bigger challenge was more modern sub-caliber (APFSDS) ammunition. During one of the tripartite weapon test (UK, FRG, USA about main gun -milit) one APFSDS fired from a German smoothbore 120mm gun overpass on of he "Cobhan" armour variant whit velocity simulating the hit from 6000m distance. Developed heavier version of the armour was however, pierced only from 200m distance.


Translate part 2:

Later, the designers were able to increase the resistance of the modules. At the beginning of 1970, reported: "All technical problems attaching armor so that it have the ability to repel (windstand) many attacks have been overcome. For example, the first module of the front of the hull withstood (survive?): 9 SC warhed attack, including 5 SC whit 152mm caliber (diameter) and 4 whit 127 mm caliber (diameter). Second (Buringhton module -milit) stopped 120mm HESH round, which was followed by many 127mm diameter SC warhed hits. The other (Burlinghton armour module -milit) survive 3 APDS cal.105mm and after that hits (more then two? milit) by 127mm diameter SC." In July 1970 the "biscuit" No. 4 (Burlinghton version -milit) mounted whit some kind of amortisation on 50mm thick RHA plate (front hull) survive multiple hits by: 105mm round from "0m distance", 152mm diameter Shillelagh warhed, two SC 152mm dimater test warhed and finnaly 120mm APDS whit velocity like on 1300m distance hit. Ability to protect against multiple attacks has become an important asset, of the " Burlington " armour.

This above is last hard data known about burlington-style armour. In case Leopard-2A4 we can assume or estimate armour protection.

They are sevral metods to estimate armour protection, and most of them give simmilar result in two groups of the option (the best and the worst), avarage between both options give us sucht values:

For turret for:

860-760-620mm LOS

(turret front, turret front for 30 degree, turret sides for 30 degree)

vs APFSDS (in mm RHA)

570-510-410mm

vs HEAT (in mm RHA)

910-810-640

hull for 640mm LOS thickness:

circa 500mm vs APFSDS and circa 700vs HEAT

Such values should be compare whit ammunition level in 1980s:

ammo mark penetration achievable (A) on 2000m,  - penetration guaranteed (G) on 2000m

3BM-26: A: 440mm G: ~400mm
3BM-29: A: 450mm G: ~410mm
3BM-32: A: 500mm G: ~460mm
3BM-42: A: 460mm G: ~430mm

and whit typical SC (HEAT) warhead abilities:

9М111М (1983) penetration  600 mm RHA;
9М120 (1985) penetration  800 mm RAH;
9М128 (1985) penetration  650 mm RHA,
9M119M Инвар (1992?) penetration  700- 750 mm RHA
Kornet (1993) penetration  1100 mm RHA,

As we can see during whole 1980s. Leopard-2A4 armor in theory was good enough protection - at least for turret and hull front even on circa 1000m distance. For the other hand: Soviet tanks protected by heavy Kontakt-5 ERA armor was very difficult enemy for western tanks.