The Leopard 2 Thread

[SH_MM]

Your drawing is missing some parts of the armor, you are looking at the tank from the front, but ignore that a large part of the sloped roof visible from the front actually belongs to the armor modules; therefore it should have a higher protection level. On the right side of the turret, the thicker roof armor would extend up to the commander's PERI R17, on the left side it is a bit shorter. Furthermore the steel elements used to mount the gun trunions are not part of your armor scheme. Here illustrated with your old CAD drawing:

 

 

 

 

 

 

That would reduce the vulnerable area of the roof and slightly reduce the size of the weakened zone of the gun mantlet.

 

As for the Swiss trials, I don't think they said anything about the protection level of the Leopard 2. Spielberger just wrote that the protection of the Abrams was better, the official report does clarify this by using different, more exact wording: the protection of the M1 Abrams was found to be "umfassender" ("wider", "more comprehensive"), which is probably a statement made in relation to the different armor coverage (Leopard 2 has shorter heavy ballistic skirts, no composite armor at the turret bustle, etc.). 

 

You also write that the protection level is achieved against 1970s ammunition, yet the Swedish documents do not mention what type of ammunition was used to establish the protection level. Given that the values are taken from a comparison with more modern Leopard 2 variants, it seems rather unlikely that they reference 1970s ammo (if you want to compare the protection values of various tanks, it makes most sense to use the same ammo for all tanks).

 

Regarding the hull side armor, it seems that the crew compartment is better protected (thicker side armor) than the rear section of the hull. In case of the Leopard 2K and Experimentalentwicklung Keiler, the frontal section was quite a bit thicker. Keiler had 40 mm side armor at the crew compartment (lower section) and 29 mm at the engine compartment. The Leopard 2K had 39 mm at the crew compartment and 29 mm at the engine compartment. The lowermost section that you have labeled with 25 mm steel-equivalent protection against KE ammo is highly sloped (just compare it to the front view), which IMO suggests that it should be a bit thicker when hit from the side.

 

[DrunkenMaster]

13 hours ago, Laviduce said:

 

The mantlet seems to be 420 mm thick. This is followed by  the hollow trunnion block giving a total LOS thickness of 680 to 730 mm.

 

You should update your drawing then. I don't get how you are arriving at the 280mm protection vs KE.

 

[Laviduce]

2 minutes ago, DrunkenMaster said:

 

You should update your drawing then. I don't get how you are arriving at the 280mm protection vs KE.

 

 

If the mantlet is using the same armor makeup  as the turret cheeks with the same thickness efficiency  we have =>  mantlet composite array (KE resistance of = ~220 mm) +  25 mm steel+ ~180-230 mm air gap + 25 mm steel = ~270-280 mm KE resistance against APFSDS rounds.

 

[DrunkenMaster]

So the whole gun assembly behind the mantlet made out of titanium is actually thin air, or cardboard maybe? Good to know, thx! 

[Laviduce]

2 minutes ago, DrunkenMaster said:

So the whole gun assembly behind the mantlet made out of titanium is actually thin air, or cardboard maybe? Good to know, thx! 

 

Leopard 1:

 

Leopard 2K:

 

These images made me believe that the Leopard 2 trunnion interior is "...actually thin air, or cardboard..."

 

 

[DrunkenMaster]

Can anyone confirm this? If yes, it's a logical explanation, thx!

[Laviduce]

14 hours ago, SH_MM said:

Your drawing is missing some parts of the armor, you are looking at the tank from the front, but ignore that a large part of the sloped roof visible from the front actually belongs to the armor modules; therefore it should have a higher protection level. On the right side of the turret, the thicker roof armor would extend up to the commander's PERI R17, on the left side it is a bit shorter. Furthermore the steel elements used to mount the gun trunions are not part of your armor scheme. Here illustrated with your old CAD drawing:

 

  Hide contents

 

 

 

 

That would reduce the vulnerable area of the roof and slightly reduce the size of the weakened zone of the gun mantlet.

 

As for the Swiss trials, I don't think they said anything about the protection level of the Leopard 2. Spielberger just wrote that the protection of the Abrams was better, the official report does clarify this by using different, more exact wording: the protection of the M1 Abrams was found to be "umfassender" ("wider", "more comprehensive"), which is probably a statement made in relation to the different armor coverage (Leopard 2 has shorter heavy ballistic skirts, no composite armor at the turret bustle, etc.). 

 

You also write that the protection level is achieved against 1970s ammunition, yet the Swedish documents do not mention what type of ammunition was used to establish the protection level. Given that the values are taken from a comparison with more modern Leopard 2 variants, it seems rather unlikely that they reference 1970s ammo (if you want to compare the protection values of various tanks, it makes most sense to use the same ammo for all tanks).

 

Regarding the hull side armor, it seems that the crew compartment is better protected (thicker side armor) than the rear section of the hull. In case of the Leopard 2K and Experimentalentwicklung Keiler, the frontal section was quite a bit thicker. Keiler had 40 mm side armor at the crew compartment (lower section) and 29 mm at the engine compartment. The Leopard 2K had 39 mm at the crew compartment and 29 mm at the engine compartment. The lowermost section that you have labeled with 25 mm steel-equivalent protection against KE ammo is highly sloped (just compare it to the front view), which IMO suggests that it should be a bit thicker when hit from the side.

 

 

 

1)      Yes, i simplified the diagrams to show the approximate areas of vulnerability.  Here is a more detailed breakdown of the  roof area of the model:

 

Overall, i would still consider this roof area to be a weakened zone given the quickly decreasing LOS thickness of the special armor and thinness of the roof plate.

 

The trunnion area follows the same example. I assumed that this zone belongs to the 500+ mm RHAe areas in the diagram. I  set this value to 5% of the total surface.

 

 

 

2)   Spielberger said the following about the Leopard 2 vs. M1 Abrams Swiss tank trials  (1981-1984):

 

"Der Leopard 2 zeigte sich seinen Konkurrenten in den Kriterien Feuerkraft und Beweglichkeit ueberlegen und beim Schutz nicht ganz gleichwertig." 

 

"The Leopard 2 demonstrated that it is superior compared its competitors in terms of firepower and mobility but not totally an equal when it comes to protection"

 

Source: Walter J. Spielberger - Waffensysteme Leopard 1 und Leopard 2  - Page 342.

 

 

The Swiss National Archives might have already declassified at least some of the results of these trials. The following link suggests that they have something:     https://www.swiss-archives.ch/detail.aspx?ID=4687655

 

A) Bericht über die Truppenvergleichserprobung Leopard 2 und M1 ABRAMS, 1981-1982   (Archive ID:  E5560D#2007/169#29)

 

B) Leopard 2 Strukturbaum Bewertung/ Vereinbahrung, 1981-1982  (Archive ID: E5560D#2007/169#31)

 

C) Evaluation neuer Kampfpanzer (Schlussbericht über die Technische Evaluation Neuer Kampfpanzer), 1982-1982 (Archive ID: E5560D#2007/169#32)

 

3)  I agree

 

4) Concerning the sponson. I am not that sure about the KE and CE protective properties of a 10 mm steel plate + 490 mm diesel fuel cell + 50 mm of steel.   How would you estimate it ?

 

Also, the angled lower front hull section seems to be about 20 -25 mm thick. According to the diagram below, the side plates are angled at about 51-52 degrees from the horizontal giving us a LOS thickness of 25-32 mm:

 

 

[Xoon]

Does anyone know what type of motors and controllers used in the elevation/traverse mechanism, as well as the fire control system in the Leopard 2? 

 

- For example, does the electric version use a stepper motor, BLDC, PM, Induction or synchronized motor?

- Do they employ dynamic or DC injection breaks?

     - If mechanical breaks are used,  are they spring-loaded? Do they run on AC or DC? 

     -Is regenerative breaks used?

     -Is the controller a simple on/off, soft starter, transformer or solid state controller? 

 

-Does the hydraulic system require breaks?

-Does the fire control system directly control the motors, or through the controls of the operator?

[Laviduce]

On 24.3.2018 at 11:33 AM, Xoon said:

Does anyone know what type of motors and controllers used in the elevation/traverse mechanism, as well as the fire control system in the Leopard 2? 

 

- For example, does the electric version use a stepper motor, BLDC, PM, Induction or synchronized motor?

- Do they employ dynamic or DC injection breaks?

     - If mechanical breaks are used,  are they spring-loaded? Do they run on AC or DC? 

     -Is regenerative breaks used?

     -Is the controller a simple on/off, soft starter, transformer or solid state controller? 

 

-Does the hydraulic system require breaks?

-Does the fire control system directly control the motors, or through the controls of the operator?

Hi Xoon,

 

I do not have all the information you requested but this might be of interest. According to Krapke:  For the Leopard 2(A0-A4) the gun laying system or Waffennachführanlage (WNA) is known as H22.  It is a electric-hydraulic retarder control eqipped hydrostatic motor where an electric motor powers a coaxial piston pump which pumps the hydraulic fluid out of the reservoir into hydro storage cell.

 

Here is the diagram of the WNA H22:

 

 

[Xoon]

On 28.3.2018 at 6:52 PM, Laviduce said:

Hi Xoon,

 

I do not have all the information you requested but this might be of interest. According to Krapke:  For the Leopard 2(A0-A4) the gun laying system or Waffennachführanlage (WNA) is known as H22.  It is a electric-hydraulic retarder control eqipped hydrostatic motor where an electric motor powers a coaxial piston pump which pumps the hydraulic fluid out of the reservoir into hydro storage cell.

 

Here is the diagram of the WNA H22:

 

 

Would you mind translating the name of the colors?

 

Also, thank you very much!

[Laviduce]

On 29.3.2018 at 11:39 PM, Xoon said:

Would you mind translating the name of the colors?

 

Also, thank you very much!

 

 

Hello Xoon !

 

Here are the translations:

 

red -   Operational Pressure

orange - Control Pressure/Actuators

yellow - Pre-control pressure

green - Recoil

white - N₂

white -  Air

 

These should be about right.

[Xoon]

On 2.4.2018 at 8:07 PM, Laviduce said:

 

 

Hello Xoon !

 

Here are the translations:

 

red -   Operational Pressure

orange - Control Pressure/Actuators

yellow - Pre-control pressure

green - Recoil

white - N₂

white -  Air

 

These should be about right.

Thank you!

[SH_MM]

Apparently the frontal turret armor modules fitted to the Leopard 2A4M CAN are empty and consists of a single armor plate (might be NERA, but I don't see any of the bolts as usually found on the Leopard 2A5's frontal heavy NERA sandwich plates). The description of these photos claims that additional armor can be internally mounted, however there are no signs of attachment points for this.

 

 

Leopard 2A5DK damaged by an IED in Afghanistan:

 

Quote

 

2)   Spielberger said the following about the Leopard 2 vs. M1 Abrams Swiss tank trials  (1981-1984):

 

"Der Leopard 2 zeigte sich seinen Konkurrenten in den Kriterien Feuerkraft und Beweglichkeit ueberlegen und beim Schutz nicht ganz gleichwertig." 

 

"The Leopard 2 demonstrated that it is superior compared its competitors in terms of firepower and mobility but not totally an equal when it comes to protection"

 

Source: Walter J. Spielberger - Waffensysteme Leopard 1 und Leopard 2  - Page 342.

 

 

As I previously wrote, he said "not equal", which doesn't mean that the frontal armor protecttion is lower; given that the Abrams has more side armor (more area is covered by the heavy side skirt modules and the turret bustle is fitted with thick composite armor), the quote from Spielberger doesn't need to have any relation to frontal armor protection. I don't see this quote disagreeing with what I wrote earlier.

 

The documents in the Swiss archives are not available to the public yet, see the column "Zugänglichkeit gemäss BGA: In Schutzfrist". However the titles of the document also confirm that the AMX-32, Merkava and the Challenger 1 were considered as optiopns at one point of time.

[Mighty_Zuk]

1 hour ago, SH_MM said:

Apparently the frontal turret armor modules fitted to the Leopard 2A4M CAN are empty and consists of a single armor plate (might be NERA, but I don't see any of the bolts as usually found on the Leopard 2A5's frontal heavy NERA sandwich plates). The description of these photos claims that additional armor can be internally mounted, however there are no signs of attachment points for this.

 

 

Leopard 2A5DK damaged by an IED in Afghanistan:

 

As I previously wrote, he said "not equal", which doesn't mean that the frontal armor protecttion is lower; given that the Abrams has more side armor (more area is covered by the heavy side skirt modules and the turret bustle is fitted with thick composite armor), the quote from Spielberger doesn't need to have any relation to frontal armor protection. I don't see this quote disagreeing with what I wrote earlier.

 

The documents in the Swiss archives are not available to the public yet, see the column "Zugänglichkeit gemäss BGA: In Schutzfrist". However the titles of the document also confirm that the AMX-32, Merkava and the Challenger 1 were considered as optiopns at one point of time.

 

So that's how they keep a lower weight... Still, the AMAP should provide rather substantial protection according to its advertisement, so even if there are no attachment points we can see, it's probably not just that empty shell.

 

And since the writer says the Leopard 2 is superior in firepower and mobility to contemporary designs, if it really was better in its protection then it would be said to be superior in that department as well. Saying "not entirely equal" in that context infers slightly worse.

[SH_MM]

The Leopard 2A4M doesn't use AMAP from Rheinmetall/IBD, but a protection kit from KMW. A Leopard 2A4 with AMAP is said to achieve the same levle of frontal protection as a Leopard 2A7, that is not the case with the Leopard 2A4M CAN.

 

9 minutes ago, Mighty_Zuk said:

And since the writer says the Leopard 2 is superior in firepower and mobility to contemporary designs, if it really was better in its protection then it would be said to be superior in that department as well. Saying "not entirely equal" in that context infers slightly worse.

 

Having less side armor makes it worse in this area; it depends on how the protection is valued. Spielberger probably based his statements on Swiss documents, which might have gone deeper into detail. The CV90 for example was considered better protected than the Marder M12 and the Warrior 2000, despite a similar level of armor protection, because the smaller size and location of the fuel tank were seen as superior by the Swiss military. In that sense the Leopard 2 could have equal armor at all places (which it doesn't have), but still would be seen as not equallly well protected due to the ammunition storage.

[Laviduce]

5 hours ago, SH_MM said:

Apparently the frontal turret armor modules fitted to the Leopard 2A4M CAN are empty and consists of a single armor plate (might be NERA, but I don't see any of the bolts as usually found on the Leopard 2A5's frontal heavy NERA sandwich plates). The description of these photos claims that additional armor can be internally mounted, however there are no signs of attachment points for this.

 

 

Leopard 2A5DK damaged by an IED in Afghanistan:

 

 

As I previously wrote, he said "not equal", which doesn't mean that the frontal armor protecttion is lower; given that the Abrams has more side armor (more area is covered by the heavy side skirt modules and the turret bustle is fitted with thick composite armor), the quote from Spielberger doesn't need to have any relation to frontal armor protection. I don't see this quote disagreeing with what I wrote earlier.

 

The documents in the Swiss archives are not available to the public yet, see the column "Zugänglichkeit gemäss BGA: In Schutzfrist". However the titles of the document also confirm that the AMX-32, Merkava and the Challenger 1 were considered as optiopns at one point of time.

 

"...doesn't mean that the frontal armor protecttion is lower; given that the Abrams has more side armor..."  I concur!

 

Concerning the M1 Abrams vs Leopard 2A1 protection question, I was somewhat confused about the comment by Spielberger.   Looking at my protection solution of the Leopard 2A1 and the estimates of the M1 Abrams it seems that the turret front of  the Leopard 2 might actually be  better protected against KE (and maybe CE) rounds  compared to the M1.  The front hull of the M1 seems to be better protected than the Leopard 2.  The side turret of the M1 is better protected compared to the Leopard 2 for somewhat obvious reasons.  Reading the Spielberger comment I always assumed that all aspects of both the turret and the hull of the Leopard 2 were not as good protected compared to the M1. I never considered that the protection difference issue might be a bit more complex than that.

 

Also, according to the Archives the documents in Schutzfrist could be cleared for access if requested in about 4 to 6 weeks.   They will let me know further details.

 

 

[Wiedzmin]

 

 

Laviduce, about your scheme with 80mm at bustle  turret side, Leopard-2 never had plates thicker than 45mm, and turret side - spaced armor with 90mm LOS, not 80mm RHA plate, if you do not believe me, you can knock this part in some museum with your fist (of course, if you do not have the opportunity to use USG) and realize how thin the outer plate is there, main requirement for turret bustle side spaced armor - protection from 14,5mm and 20mm, thats all. 

 

and of course turret roof have only 40 and 20mm plates, not 70... 

[Laviduce]

On 14.4.2018 at 3:52 PM, Wiedzmin said:

 

 

Laviduce, about your scheme with 80mm at bustle  turret side, Leopard-2 never had plates thicker than 45mm, and turret side - spaced armor with 90mm LOS, not 80mm RHA plate, if you do not believe me, you can knock this part in some museum with your fist (of course, if you do not have the opportunity to use USG) and realize how thin the outer plate is there, main requirement for turret bustle side spaced armor - protection from 14,5mm and 20mm, thats all. 

 

and of course turret roof have only 40 and 20mm plates, not 70... 

I thought so too. My original believe  was that it has a LOS thickness of about 60 mm: "The bustle rack side armor seems to be spaced and around 60-70 mm thick. (1 Possible solution: 35 mm steel-10 mm air gap + 15 mm steel). "

 

I was not sure if the outer shell was the thinner or thicker plate.

 

But then an Ex Leopard 2A4 tanker had this to say:  " It is around 80-85mm with air gap inside not thicker than 15mm,..."

 

Concerning the roof, I was getting ready to set the roof thickness at 30 mm where the hatches are and about 45 mm where  the sloped front roof is. In the Hilmes diagrams it looks like that part is about 40-45 mm thick, so i was thinking about going with the 45 mm.

 

 

Also  the Swiss archives had to this to say about the Leopard 2 documents:

 

"Experience shows that about 85-90% of the requests for insight are granted (viewed as a whole). Therefore, I could well imagine that your application would be approved accordingly.

 The term of protection for these documents is 80 years. This means that you will be freely accessible from the year 2063. I suspect that this takes too long.

 However, you are welcome to submit an application for access to these three dossiers at www.swiss-archives.ch. The processing of such an application usually takes 4-6 weeks. Any authorization is then valid for life."

[Wiedzmin]

 

2 hours ago, Laviduce said:

(1 Possible solution: 35 mm steel-air gap + 15 mm steel). "

 

not  far from real life steel thicknesses... 

 

 

[SH_MM]

I posted about this on another forum quite a while ago, so you may already know this: The company FWH manufactures cast armor parts for German AFVs. It offers three quality classes. Quality class "P" with a hardness of 350 to 380 on the Brinell scale was used for the Leopard 2 to 2A3 (I suppose the early batches of 2A4 tanks also received casts parts of the same quality class). Quality class "Q" with a hardness of 380 to 420 HB was used on the Leopard 2A4, 2A5 and the 2A6 models for Greece and Spain. The quality class "R" with a hardness of 480 to 520 HB is used for the Puma and Boxer. Most German combat vehicles make use of welded armor, so this info is rather meager. However the Boxer uses 45 cast armor parts made by FWH with a size of up tp 1,600 mm.

 

On the Leopard 2 cast armor elements might be used for the gun mount, the mounting system for the suspension elements and maybe parts of the hatches. But this information gives a general idea about what steel was used for this tank and how protection was improved from the earlier models to the later Leopard 2A4 batches and the following models.

 

Welding is done austenitic for steel elements of quality class "P" and ferritic for the quality classes "Q" and "R".

 

 

There is a document suggesting that the welded steel plates for the Leopard 2's basic construction were delivered by the Stahlwerk Geisweld. The steel is branded "HFX 130" and has a thickness ranging between 5 and 45 mm depending on location. Unfortunately there is no HFX 130 steel being advertised anymore. An interessting fact is that the Stahlwerk Geisweld is nowadays owned by Schmolz und Birkenbach, which also owns the Swiss company SteelTec. While Stahlwerk Geisweld seems to be focused on manufacturing stainless steel for industry applications, SteelTec offers a product called "HSX 130". Given that the "HF" stands for "hochfest" (German for "high strength") and "HS" also stands for "high strength", both of these steel alloys might be the same.

 

HSX 130 steel is offered with a maximum thickness of 45 mm (like shown in the German document mentioning HFX 130) and has a hardness of 395 HB on average (tensile strength ranges from 1,250 to 1,400 N/mm². This might be used on the Leopard 2, given that flyers from Krauss-Maffei talked about the high quality steel used for the tank.

 

___

 

German Leopard 2A6MA2 being handed over to the Netherlands:

 

 

 

[Wiedzmin]

7 hours ago, SH_MM said:

I

HSX 130 steel is offered with a maximum thickness of 45 mm (like shown in the German document mentioning HFX 130) and has a hardness of 395 HB on average

 

 

 

 

 

Soviet BTK-1 and BTK-1Sh used on T-80 have same hardness IIRC 

[Xoon]

On 4/27/2018 at 2:27 PM, SH_MM said:

Welding is done austenitic for steel elements of quality class "P" and ferritic for the quality classes "Q" and "R".

What is austentic and ferritic welding?

[TokyoMorose]

9 minutes ago, Xoon said:

What is austentic and ferritic welding?

 

Different crystal phases of the steel, essentially the grade "P" armor is welded while still hot, the other grades are welded at much cooler temperatures. Likely implies that the grade P material is welded post-heat-treatment, while the grade Q and R metal is welded pre-heat-treatment. (This is not necessarily the case, but would be the most likely reason for welding at different phases).

[Xoon]

1 minute ago, TokyoMorose said:

 

Different crystal phases of the steel, essentially the grade "P" armor is welded while still hot, the other grades are welded at much cooler temperatures. Likely implies that the grade P material is welded post-heat-treatment, while the grade Q and R metal is welded pre-heat-treatment. (This is not necessarily the case, but would be the most likely reason for welding at different phases).

Thanks for the great explanation. 

 

But how do you heat treat a tank chassis?

[TokyoMorose]

8 minutes ago, Xoon said:

Thanks for the great explanation. 

 

But how do you heat treat a tank chassis?

 

I am not sure how it is done for Leopard 2 components, but I have seen entire cast or welded assemblies heated up and quenched at once in appropriately massive facilities. This image of a Panzer 68 hull being Quenched at Thun always comes to mind.

 

Welding plates post heat-treatment is very difficult without making the zone around the weld weak. It is usually preferred in metallurgy to weld before heat treatment and then do it all together.