Scav

2 hours ago, SH_MM said:

There have been different versions of Laviduce's estimations. He originally believed the right turret cheek to be weaker than the left one, but a closer look at the graphs from Lindström's presentation show that the right cheek actually was better protected. The size of the EMES-15 gap seems to be a bit too much, i.e. overall armor module thickness seems to be nearly identical on the lower right and the left cheeks, but the former includes addiitonal space between the modules, enhancing overall protection.

 

Note that the thickness of the armor array below the EMES-15 sight is pretty much the only place where the thickness was guesstimated, while for the other places actual measurements were available. It also seems to be a place with a bit more variable thickness, as the front and rear walls of the EMES-15's cavity are not parallel. On the left edge the frontal armor module seems to be about 400 mm thick.

 

So I should assume a higher protection under the EMES-15.

2 hours ago, SH_MM said:

This "book" happens to be the German wikipedia article on the Leopard 2 (in a slightly outdated form). The authors of the article happen to have a rather limited understanding of the armor generations, for example due to their generalizing and simplified writing style, they claim that all Leopard 2 variants (including the original production model from 1979 and the current Leopard 2A7 from 2014) feature armor in C-technology. The armor in D-technology is only mentioned as side skirt armor, because Lobitz mentioned only the side skirts directly.

Ha, lol.

I should've checked it, the layout seemed odd for a book...

Well, to be fair, they did give their sources and as far as I can tell what they claim about the 2A4 is more or less correct.

At least Frank Lobitz says the same things (one of their sources actually).

2 hours ago, SH_MM said:

The problem is that most authors do not use the terminology with "B", "C" and "D" technology armor arrays in their books and do not specify how the armor was changed. They mention that the late model has "improved protection" or general armor technology ("armor in C technology", "armor in D technology", "3rd generation armor", "4th generation armor") without mentioning anything specific about where the armor was used - if the Leopard 2A4 from 1991 would only have the improved skirt armor according to F. Lobitz's "Kampfpanzer Leopard 2 - Entwicklung und Einsatz in der Bundeswehr", then other authors could refer to the same changes in skirt armor with their more generic descriptions.

I agree, it's a big mish mash and you're never quite sure what they mean.

Especially the "generations" are odd because they might even assume there was an older generation than B tech for all we know.

2 hours ago, SH_MM said:

However I am not sure if Frank Lobitz doesn't only mention the skirts, because it is the only visible change. He didn't specify anything about the base armor remaining identical to the Leopard 2A4 from 1988 (although he mentioned there, that the base armor was changed), he might not have been sure while writing his book. Note that the table listing the changes mentioned by Voodoo is located on page 126, it specifically mentions the skirts, but on page 127 is the following image with caption:

Well, the way I see it there's two options: either he had good info regarding the upgrades carried out (he mentions base armour being upgraded in the 1988 model which AFAIK is confirmed) or he didn't have good info and guessed based upon other authors and pictures, in which case he might not have known that the 1991 models had improved internal armour too.

But considering he specifies that the internal armour was upgraded in the 1988 model while saying only the skirts were upgraded for the 1991 model, I would think he does actually have decent info.

3 hours ago, SH_MM said:

The German caption of the upper photograph includes the word "auch" (in English: "too", "also"), which is excluded from the English translation. This might either mean that the Leopard 2 from 1991 also featured armor in "D" technology in the chassis and turret or that it also features "D" technology armor like other tanks. The problem with the latter is that nearly two dozen pages in front of this caption are focused on describing the older versions of the Leopard 2. so the whole situation with Lobitz's book is rather odd. To add to this confusion, he mentions in the table in page 126 that the heavy side skirts would also be in "D" technology (albeit looking identical to those fitted to the Leopard 2 from 1988 with "C" generation armor), which would mean that at least.

I think he's trying to say this:

Quote

Compared to the 6th and 7th batches the vehicles of the 8th batch now also have light skirts in D technology.

So it seems he's putting emphasis on "now also", which to me makes it seem like he's pointing it out as the sole difference.

That said, German isn't my native language (and I'm a bit rusty) nor do I have that book to properly judge the context.

3 hours ago, SH_MM said:

I don't really see the point in changing only the skirt armor, if the rest of the armor remained completely unchanged - specifically if it is only the light skirt (which offers no protection advantage, but is more expensive, as HHS costs several times more than perforated RHS in rubber). If the composition of the heavy skirts was also altered, the hull would be better protected from impacts at an angle than frontally...

Well, it could very well be a more optimised skirt than previous models which was ready before the rest of "D tech", so ready for early adoption.

I recall seeing a picture of a leopard 2 skirt somewhere with "holes" under the surface, not sure if that was the early variant or a later one.

I doubt those skirts can offer more protection than the frontal armour even if it's at, let's say, a 15° angle.

From pictures and what @Militarysta posted on his leo 2A4 armour measuring page, it seems to me that the early skirts weren't that heavy or dense, probably consisting of spaced plates that aren't very thick.

At the same time, they also started using C tech midway through a batch, that seems like a bigger change than some different skirts.

Hence I don't think changing skirts was a major thing or would be "held back" to coincide with an internal armour change.

3 hours ago, SH_MM said:

Also a curious fact is a snipplet from page 183, where the author mentions that the Leopard 2A4 from 1991 uses "second generation light side skirts" (in his nomenclature, which probably isn't official, as other authors use "second generation" in reference to the armor in "C" technology), while the Leopard 2A5 and 2A6 use "third generation light side skirts" - the layout seems identical, but the location of the screws is different (maybe the thickness too, but this might be the result of artistic freedom of the man who made the sketch showcasing the differences). This might again point to a difference in D-1 (first type of skirt armor made in "D" technology) and D-2 (second type of skirt armor made in "D" technology) armor arrays being used.

Interesting.... possibly a typo or maybe even a contradiction to what he earlier said?
Could very well be a small difference.

Mounting points being different could indicate a new skirt possibly being heavier or lighter.... or it could possibly be an optimisation from field testing showing different mounting points were desirable.

2 hours ago, Voodoo said:

He does not go into detail about the D-technology, I'm afraid. The only thing being mentioned about armour, is about the sixth/seventh batch. "From the 97th vehicle onwards, a modified version of the spaced multilayered armour(Beulblechpanzerung), externally not visible, was installed. (KMW)"

That would refer to C tech as far as I know.

Still, good info, don't find much of that.

1 hour ago, LoooSeR said:

 That "Streetfighter" is rather sad, no side armor, no equipment to go through baricades/ruins, MG positions have no protection. Even crappy T-72B urban kit is somewhat better in that regards.

It's British, they'll just use teabags as side armour.

2 hours ago, Voodoo said:

This is what Frank Lobitz writes in Kampfpanzer Leopard : Entwicklung und Einsatz in der Bubdeswehr(Development and Service in the German Army):

 

Talking about the 8th production batch: 

"In contrast to vehicles of the sixth and seventh production lots, those of the eighth production lot features light side skirts that incorporate D-technology. (KMW)"

 

Further, he goes on about the prototypes for the 2A5:

"....A maximum of 62.5 tonnes was set as the weight limit. Chief efforts were conducted in the field of armour protection. The add-on armour packages were designed with D-technology(similar to fourth-generation spaced composite armour) and,depending on their location on the vehicle, were either integrated(turret front/chassis) or mounted on the top(turret roof). For the first time  add.on armour modules were mounted in front of the original armour of the turret front and chassis, and this changed the appearence of the vehicle significantly."

Thanks!

So I assume he doens't talk about wether or not the base armour was changed in type?

2 hours ago, Voodoo said:

Sorry for barging in to your conversation and if not understanding your question..

This was the information I was looking for, thanks!

@SH_MM
I've recently found this book again:

https://www.yumpu.com/de/document/view/10795487/leopard-2-gfj-hostingde

It also talks about the leopard 2A4 and the different technologies:

It's saying one of the improvements was new skirts, both light and heavy in D-tech.

Which IMO makes sense given there's leopard 2A5s with both these and C tech ones.

There's some minor issues with this book, namely they seem to have taken some internet estimates for the armour....

Anyway, would you mind sharing what Rolf Hilmes or other authors have to say about this?

Could you maybe show a small snippet of the books you use?

1 hour ago, That_Baka said:

@Scav

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I refered to Abrams UFP which is really hard to uparmour.

True, the biggest downside of that design arguably.

13 hours ago, Mighty_Zuk said:

The mantlet being reinforced with composite armor, perhaps to the point of being nearly as strong or as strong as the rest of the turret front, is neither unique to the Leopard 2A5-7, nor is it very uncommon.

 

Other tanks like the Abrams, Merkava, and perhaps the T-tanks (barring the T-14), plus maybe the Challengers (though not too sure) have well protected mantlets.

Hm, Abrams seems to have quite a thin mantlet in comparison with the rest of the turret though, Merkava is definitely also one that has good protection around the gun, but the T-series really does have a weaker area around the gun than the rest of the turret, even on the T-90A it's only protected by normal steel blocks, Challenger 2 did seem to have an OK mantlet but it's still thinner than the rest of the turret front, so unless there's some armour block or spallshield behind that I would still consider it weaker than the rest of the turret.

3 minutes ago, alanch90 said:

T-14 turret has much less chances of being hit by anti tank fire compared to manned tank turrets. Firstly because of the very small volume/surface which if hit would result in mission kill compared to manned turrets (from the front, the T-14 turret vulnerable area is around the same size as other tanks mantlet which are also weak points) and also the APS which is claimed, not proven, to intercept APFSDS.

Small size from the front, yes, from the side it's not that small.

Mantlet on some tanks is weak, but others like the 2A5 isn't, though that's mostly an exception to the rule.

3 hours ago, That_Baka said:

Doesnt change that fact abrams armour arrays have cover much amount of space though. So it is better optimised.

Different design philosophy, can't directly compare the "efficiency" of the armour layout to each other since one has an unmanned turret that is likely paper to any calibre of 90mm or higher while the other has the heaviest armour on the front of the turret.

So, while the abrams has to cover a lot of space, it also does a good job of that, unlike the T-14 which relies entirely on not getting hit in the turret by any decent KE or HEAT shell.

You might argue that the crew will live because they're not in the turret, but you don't know that, if their capability to fight back has been neutralised that means anything can then follow up, even IFVs, which will absolutely wreck any optics making the crew blind so they have to rely entirely on poor vision or GPS to find their way back to cover.

Even if the tank does get out of the situation with "only" a firepower kill, that's still a neutralised tank, if that was an M1A2, it could've taken the hit and potentially fired back.

Sure, the T-14 probably is more weight optimised, but you're also comparing a late 70s tank to a mid 2000s tank while not taking into account the consequences or results of that higher weight optimisation.

On 11/20/2018 at 2:05 AM, alanch90 said:

You shuldnt speculate with weight alone. The Abrams turret (without the DU inserts) weights by itself 20 tones. And T-14 turret has no heavy armor, so the tanks weight is differently prioritised.

Fixed that for you.

2 hours ago, SH_MM said:

Not regarding the armor of the Leopard 2/Stridsvagn aside of (incorrect) internet estimates for the Leopard 2A0 armor protection.

In general there seems to be information that I'm not able to find readily on the web, I'm really looking for small details and mechanics and such.

3 hours ago, SH_MM said:

That is probably a mistake caused by the hatch sliding mechanism sitting in front of the hatch. On the Leopard 2 up to (and including) the 2A4 variant, the hatch swivels. The new sliding hatch adopted with the Leopard 2A5 requires a different mechanism, which is mounted in front of the driver's hatch (and also the hatch itself seems to have become a bit thicker).

Yeah, it's not easy to see the thickness of either without having a measuring tape.

It was just a rough guess.

3 hours ago, SH_MM said:

The Leopard 2A6NL is - like the Germany Leopard 2A5 and Leopard 2A6 - built to the Mannheimer configuration, hence the hull did not receive an add-on armor module and is largely unchanged (aside of the new hatch and rear drive camera) compared to the later batches of the Leopard 2A4.

Yeah, I expected some minor changes in the hull and I didn't know C tech was weight neutral.

3 hours ago, SH_MM said:

The Dutch tanks originally had "B" generation main armor, but apparently this was changed (the heavy skirts of the "C" generation were adopted, so base armor might also have been altered). The turrets likely have "D" generation main armor like the German model.

So more or less a complete overhaul of the armour?

3 hours ago, SH_MM said:

I don't think they offered all combinations of armor, that clearly wouldn't make sense.

I agree, that's why I initally thought D tech wasn't a main armour technology but small things like skirts and add-ons.

3 hours ago, SH_MM said:

The LOS thickness of the base armor on the right thickness is higher, once an armor block was added in front of the optic. According to the analysis from Laviduce, the right turret cheek of the Leopard 2 with "B" generation armor already offers a higher level of protection than the left cheek, which makes sense (below the optic, the LOS is 1,100-1,200 mm - including an empty space, but that would also improve protection a bit).

While the LOS is higher, that's mostly because of the empty space between the two blocks of armour, that might help or it might not,, logically it would atleast provide more space that the penetrator has to deal with, but if the armour packs itself are only like 650mm or so (looking at Laviduce's model) and the space in-between makes up the rest.... I don't think it would actually provide more protection than the rest, or atleast not significantly more.

Considering the turret cheeks are roughly 20% of the frontal area of the tank and that correlates to around 400mm if we look at that protection graph.

Now only around 6-7% of the surface area is protected against 500mm but that % stays more or less the same all the while it goes up to 700mm, so I don't think it's actually talking about that section under the EMES-15 but rather some other overlaps or places around the mantlet for instance where you have a lot of steel, or even the area just above the UFP on the roof where there's still special armour right under it.

If the area under the EMES-15 would indeed provide more protection I would expect that to lead to a higher % of the tank to be protected against 400mm from the +20° angle compared to the -20° angle.

Though there are some small weird anomalies like more surface area being protected of a + angle (right turret cheek, where the optic is) from 300mm and 500mm, I think that might be due to overlaps or perhaps even the added armour for the driver's side.

At the same time I'm not even sure if the armour behind the optic is weaker than the normal cheek armour, they could very well have made it denser to compensate, though for simplicity reasons this might not have been done.

What's your take on this?

Do you think the EMES-15 area is weaker and the area under it stronger despite having "less" armour but more LOS?

And, now that I think about it: wouldn't that space actually be partially filled with the traverse mechanism?
That might add quite some steel which wouldn't show up on an armour analysis but would help in reality.....

1 minute ago, SH_MM said:

Unless you have seen different documents than me, the statement comes from a document written in 1970, when the Keiler/Leopard 2 was expected to enter service before 1975 (and as a matter of fact was still using simple space armor, using MLC50 as upper weight limit). They stated that it would be possible to modify the design (to include Burlington armor) and put it into production by 1975.

Might've even been a book for all I remember, it's not that easy to find.

20 minutes ago, SH_MM said:

No, the seat is located in the same space. The additional volume above it is completely occupied by the armored hatch

Oh interesting, I'd imagine that they did something so the commander can more easily reach the hatch?

23 minutes ago, SH_MM said:

I believe it is impossible to achieve the protection level of the Swedish tank just by adding the Leopard 2A5 wedge armor to a Leopard 2A4 with "B" generation armor. It just isn't very thick, IBD Deisenroth tested a double-layered NERA array in the 1990s, which consisted of two sandwich plates (10.5 mm semi-hardened steel + 7-8 mm special material + 10.5 mm semi-hardened) - this might be related to the wedges, the overall thickness considering the slope (65°) seems to match the Leopard 2A5's wedge armor. Such an armor array would not be suitable for providing 400-500 mm steel equivalent protection (given that the Swedish MBT reaches 800-900 mm vs KE from the front).

That doesn't seem very thick no, but I think the space might still provide the necessary room for the penetrator to yaw or deform, which would massively reduce penetration.

Are you talking about this picture:

It's pretty hard to tell how thick it is, I think it says 26 or 28mm.

Might be related.

26 minutes ago, SH_MM said:

The third NERA layer doesn't actually cover a lot of frontal surface and might be adopted to improve the protection of the mantlet along the frontal arc.

I agree.

27 minutes ago, SH_MM said:

Still the slides say that the Leopard 2 "Swedish model" has at least 700 mm protection along the frontal 30° at the left cheek compared to 0° for 700 mm protection for the left cheek of the "German model".

I honestly didn't even consider that one, I find pictures like that a little bit vague so I mostly focussed on the one with the actual numbers.

28 minutes ago, SH_MM said:

He also mentions that according to his understanding the Stridsvagn 122 uses titanium armor (Ti-6Al-4V) and that the high protection requirements meant that turret and hull had to be newly built, because it wasn't possible/practical to convert existing Leopard 2s to this configuration. 

Thanks, I really need that book it seems, there's a lot of info in there I assume.

29 minutes ago, SH_MM said:

I don't know what you mean with "front hull roof was increased".

Well, from what I can tell the driver's hatch was changed and it seems like the hull roof itself might've been made thicker (I saw some picture where you could see the hatch open and compared it with a 2A4 picture, not exact science) and seen multiple people also make that claim.

32 minutes ago, SH_MM said:

The weight of a Dutch Leopard 2A6 turret is something like 19.75 tonnes compared to 15.5 tonnes for the original 2A4 (B) version.

So most of the weight changes was turret?
That would definitely indicate more changes than I thought.

33 minutes ago, SH_MM said:

the side skirts aren't actually heavier given that the frontal elements are fitted to the Leopard 2A4 with "C" generation armor (and armor changes to this variant supposedly was weight neutral compared to the earlier model) and the rear section of the new skirts adopted on the 1991 model of the Leopard 2A4 has been described as "lighter" [compared to earlier variants].

Just something I heard from two ex-loaders, one on a 2A4 and the other on a 2A6M, the 2A6M guy said those skirts were pretty damn heavy but the other one was surprised because he found them quite light.

Would've been a minimal weight difference if any.

35 minutes ago, SH_MM said:

The Stridsvagn 122 doesn't feature a mine protection. The Strv 122B (4 Strv 122 tanks converted) features the same mine protection kit as the Leopard 2A6M, the combat weight is above 64 tonnes.

I was under the impression that the weight was 62.5 for the 122B, sorry.

36 minutes ago, SH_MM said:

If they decided to use a German army version, yes. But the KVT/IVT and TVM Max. were all available with IFIS (C4I) and armor modules covering the roof and hull aswell.

Yeah I assumed the choice was between German army version and Swedish Strv 122.

38 minutes ago, SH_MM said:

For the Leopard 2 with "B" generation armor, there wasn't a combination, because the base armor wasn't combined with anything. The Leopard 2 "German model" with "B" base armor (located in column 1) and "D-2" add-on modules (located in column 4) has the technology combination 5, which is why I think that it is the sum of the columns numbers (1+4).

Makes sense, I guess they didn't bother with all the possible combinations though?

To me it makes little sense to have  B pakette + B add-on (whatever that is if it even exists, which I doubt) so that would reduce the amout of possible combinations.

About that picture for the protection angles:
I find it odd that the "German solution" doesn't give equal protection on the left turret face compared to the right turret, if it's the optic, that would be the other way around....

38 minutes ago, SH_MM said:

West-Germany got access to Burlington armor beginning in 1970 (selected scientists) and started developing a common MBT with the UK between 1972 and 1977. When the West-Germany first announced that they had developed a composite armor package for the Leopard 2, the UK assumed that it was heavily based on the knowledge and technology used for Burlington, acquired during the early 1970s.

 

However West-Germany claimed that this armor was a local development, probably based on the fact that Dr. Manfred Held (the inventor of modern ERA, as the Soviets ceased ERA research at the end of the 1950s) patented NERA in 1973.

Yeah, not sure where I read it, but I think some British source says that the leopard 2 development was already too advanced to incorporate Burlington, I'll try to find that.

39 minutes ago, SH_MM said:

The Leopard 2 TVM Max. was tested in Sweden, which was based on the chassis number 11156 and therefore belonged to the last production batch (with what I believe to be "D-1" type armor). As the TVM Max. returned to Germany after the Swedish trials, it seems that Sweden only tested armor arrays representing the corresponding Leopard 2 tanks rather than firing at real tanks - the same happened with the M1A2 Abrams. Reading through Richard Lindström's article and a few German sources, it seems that only a single Leopard 2 was send to Sweden. Therefore the tested armor arrays and thte actual tank tested by Sweden might be independent from each other.

I drew the same conclusion, though I don't know much about the TVMs.

40 minutes ago, SH_MM said:

I don't think that "German model" and "Swedish model" actually refers to "tank that Germany wants to sell to Sweden" and "tank that Sweden wants to buy", but rather to "Leopard 2 version currently considered for adoption by Germany" and "Leopard 2 version suggested by Krauss-Maffei for Sweden".

Quite likely, it also seems like the armour they wanted for the Strv 122 was a slightly later development and thus they had to make it themselves during or before the testing.

41 minutes ago, SH_MM said:

This seems to be a case of common excuses from people pretending that their own military always makes the right decisions and has infinite budget, while all others are wrong.

Could be, but to me it seems like it adds quite a bit of weight (probably less than a tonne though) and extra profile, maybe it's not needed, maybe it is, I don't know.

43 minutes ago, SH_MM said:

The increase in profile is irrelevant, given that there is no protected volume behind the roof modules in the horizontal plane.

Doesn't the commander actually sit higher though? At the very least it increases the profile so more of the tank is visible if you're in a hull down position, not sure if that's a bad thing for thermal optics but it definitely looks like a bigger target or easier to identify.

The Swedes considered it inert, but as far as I can tell it's still part of the crew comparment (atleast for the hatches).

In any case, they've done similar things in the past (German M48, lowered cupola), probably with a good reason, perhaps in hindsight the saying: "'Better safe than sorry" is applicable.

46 minutes ago, SH_MM said:

The Panzerhaubitze 2000 has received similar thick roof armor without issues, the Puma also features some (albeit thinner).

Yes, but I think for the PzH 2000 it's necessary to armour it against counter battery fire. For the Puma it's also necessary because of it's role as close infantry support.

It might also be necessary for the MBTs, IDK.

48 minutes ago, SH_MM said:

I don't think it is reasonable to argue with LOS efficiency in case of the wedge-shaped add-on armor. Unlike the base armor, the majority of its volume is hollow, the actual LOS thickness is variable depending on impact location (the maximum LOS is only reached at the center; hitting above or below it, the overall LOS will decrease massively). In terms of function, the armor is ought to be much more comparable to heavy ERA, i.e. weakening the incoming projectile in such a way that the base armor can defeat it. 

Hm, I should rephrase that: I think the purpose of the wedges was to roughly retain LOS efficiency (and thus massively increase protection) but as an overall package and not purely because of the wedge if that makes any more sense.

While they are mostly empty, they are made of more modern materials and constructed in a different manner, I wasn't trying to argue based purely on LOS effectiveness but that the wedges are cheap, light and maintain the overall efficiency of the entire armour array, they could go with denser and higher efficiency armour but that seems more expensive and more trouble than it's worth.

In that case I don't think upgrading the base armour from B to something else would be necessary to attain the 800-850mm effectiveness with the wedges, as they are made of more modern materials and do a seperate job that doesn't just "add" to the base armour but compliments it.

So despite them being way more air and less dense than the base armour, they can still provide the necessary protection in combination with the main armour to essentially double the effective armour because they are made of more modern materials.

57 minutes ago, SH_MM said:

I don't think there is actually any actual proof that there were different add-on modules being tested on the Leopard 2 Improved protoypes. While the table format chosen by KMW suggests there might have been more than just one type of add-on armor, it also includes slots/positions for "B" and "C" technology Vorsatzmodule. External the only differences between the Leopard 2 Improved prototypes and the series production models is the shape of the side add-on armor modules. which have become thinner (!) on the series production version. I'd argue that these changes could have been made to reduce weight and do not indicate any change in the composition or effectiveness of the frontal add-on armor modules.

I think they might honestly have been lazy enough not to "grey out" those boxes, another reason why I suspected "D-tech" wasn't a main armour tech despite being shown as a possibility, could also be because they had extra "blocks" similar to those fitted to the Pz 87 140 as add-on instead of wedges.

Possibly they found out that having the add-ons slightly further and at more of an angle compared to the main armour increased effectiveness despite being thinner?
They might also provide the same protection but with less weight like you say.

Same data, different conclusions or theories :).

1 hour ago, SH_MM said:

For the "German model"/KVT, the "B" armor package improves protection from ~450 mm vs KE at the left turret front to 862 mm vs KE. If we assume the same relative increase at 30°, the protection level is only at best 668 mm vs KE (the Swedish documents noted that the left turret cheeck of the "German model" of the Leopard 2 Improved is only capable of stopping an APFSDS with 700 mm penetration into steel at direct impact from the front) - please note that the efficiency of the add-on NERA probably decreases when hit from an angle, because the LOS thickness of the NERA plates is reduced, the thickness of the empty space is reduced and (most importantly) the lower angle means less material is forced into the path of the penetrator. That's why 862 mm vs KE from the front could be as low as 600 mm vs KE at 30°. The "Swedish model" is capable of providing 720 mm vs KE at 30° impact angle.

I think this could very well come from a difference in add-on modules, base armour is also possible, I have to point out that the 720mm figure is pointed right at the mantlet/breech area and not the plain cheeks like the others.

In this case I very much think different angles cannot be compared directly or "converted" to attain different figures.

The wedges are quite complex, they have two layers and because the angles differ I wouldn't call this traditional NERA but more like you said: "comparable to heavy ERA", I would go even a step further and outright claim that "converting" or calculating different angles is simply impossible.

1 hour ago, SH_MM said:

According to Rolf Hilmes' 2007 book "Kampfpanzer heute und morgen: Konzepte - Systeme - Technologien", the Stridsvagn 122 has a higher level of ballistic protection than the German Leopard 2A5 while mentioning the increased roof and hull armor as separate points.

Interesting, he didn't mean it as an overlapping statement?

Haven't found a place where I can get that book yet, I've wanted it for quite some time now.

1 hour ago, SH_MM said:

Weight. The Leopard 2A4 with "B" generation armor weighs just 55.15 tonnes. The weight of each frontal add-on armor module for the turret is about 500 kg as revealed by the Dutch army. Estimated weight of boith turret side add-on armor modules is less than 500 kg combined (they cover a similar area as the frontal modules, but are made of a single NERA layer instead of 2-3 and are less sloped). Given a combat weight of 62.500 kg, the weight of the hull add-on armor and roof armor would be about 5.85 tonnes. Comparing the weight differences of several other versions suggest that is incorrect (for example the Leopard 2A5DK and Leopard 2A7V feature hull add-on modules, but no roof armor, giving us an idea about the relative weight of both armor systems).

Don't forget the mantlet, turret drives (probably lighter) and some other internal changes though, while the Dutch did reveal the weight I wonder if they didn't round it off or kept it at 500kg just to be vague.

AFAIK the Strv 122 also incorporates the mine protection, which is probably around 1-2t.

If we compare normal 2A5 to 2A4 it's 59.7t and 55.15t, around 1.5-2t is for the turret which leaves 3-2.5t unexplained: front hull roof was increased, armour of turret roof and so was driver's hatch (not sure how much, could be little to nothing), new heavier skirts, spall liners were fitted and the armour infront of the optic was increased.
I agree that falls short of the weight difference, I don't know how much though.

1 hour ago, SH_MM said:

The Stridsvagn 122 was used as demonstrator by KMW in the Greek tests, because it was considered superior to the German tank.

IIRC it had C3I, roof protection and hull protection that was all superior to the german 2A5, that could be all or there might be more.

1 hour ago, SH_MM said:

If "D-1" would refer to the additional roof armor, why wouldn't it look like this for the "German model"/KVT? Given that the tank featured roof add-on armor...

Good point, I don't know, perhaps this was for an earlier version, though that doesn't seem likely.

1 hour ago, SH_MM said:

On the 2A4 where B was indicated it didn't mention a combination, do you think the combination number refers to the order of the selected modules?

1 hour ago, SH_MM said:

Also the term "Vorsatz-Modul" strictly translated would be "module that sits in the front", not "on top" as roof-mounted armor would do. You can try to contact Lindström, but given that he removed the original files and photographs from the armor tests from his website, I don't think he is allowed to answer your questions.

As is often said: "You have a no, but you can get a yes". 

I don't have high hopes though.

Well, I'd hoped to get more answers but it seems you've left me with even more questions  ...

I think I'll make some armour estimates for the different graphs in the leopard 2 thread with this new info.

Thanks for the input!

4 hours ago, SH_MM said:

There are multiple possiblities how the protection might have been improved without increasing weight by a significant amount, also it is worth noting that we don't know the protection level against chemical energy rounds. Replacing steel with ceramics or using higher quality steel/DHS/THS could allow increasing the KE protection without affecting the weight, likewise altering the armor layout might help (using less NERA panels, but thicker ones with HHS capable of affecting APFSDS penetrators by a larger amount).

 

There is a Russian book claiming that West-Germany tested armor arrays during the 1970s, which were more comparable to the T-72B's internal NERA array (i.e. each sandwich plate consisted of a thicker frontplate made of steel with higher hardness followed by only a very thin rubber sheet and steel plate), which seems to be more capable of defeating APFSDS ammo. If the Leopard 2's "B" technology armor follows another layout (comparable to the M1 Abrams' BRL-1 composite), then switching to this array-type at the same weight might improve protection against KE (for potentially loosing a bit of CE protection).

Yeah, I discussed this at length with one of my friends, we basically came to the conclusion B tech was probably something like spaced steel (with relatively thick plates) array either with rubber liners or suspended in rubber so it can move.

I don't think they used something like Burlington or BRL-1 simply because when the UK shared the info they also commented that Germany already had different composites and was chosing those for the leopard 2AV, still it's a possibility though I think it's less likely than the spaced array option.

4 hours ago, SH_MM said:

Think about it this way: the tanks have already been ordered years ago, so if the manufacturer has already developed a new armor package that has finished testing, why not use it?

Fair point.

4 hours ago, SH_MM said:

The TVM Min. and TVM Max. (which was used for some Swedish tests) were based on two Leopard 2A4 tanks from the eight batch and should therefore feature something like "D-1" base armor.

Hm, well as far as I can tell the Leopard 2 "improved" that was tested by Sweden and sent from Germany had the B pakette + D-2 wedges (as seen on that graph comparing leopard 2A4 variants), at least he values seem to match the ones tested by Sweden.

4 hours ago, SH_MM said:

ll prototypes of the Leopard 2A5 had the "flat" side add-on armor modules, but all series production versions featured the wedge-shaped side armor. The add-on armor used on the Stridsvagn 122 seems to be identical to the one used on all series versions of the Leopard 2A5 and Leopard 2A6 tanks. That suggests the the changes to the add-on armor proposed by Sweden might have been adopted by all Leopard 2A5/2A6 users (Ingenieurbüro Deisenroth made apparently the add-on armor for all different 2A5 versions).

I agree, it seems they accepted the Strv 122 add-ons instead of the other ones, at least the turret front, side, hull side add-ons were accepted on the 2A5.

4 hours ago, SH_MM said:

My understanding - or my theory - is that to keep the costs down Germany at the time of the Swedish trials was planning to upgrade the Leopard 2 with armor of the "B" generation by simply installing add-on armor (D-2), which Sweden considered to be insufficient, hence the proposed Swedish model featured a significantly higher level of protection. However after the Swedish trials (or during them), a number of factors (for example the decision to downsize the Bundeswehr and completely dissolve the Bundeswehrkommando Ost, the cancelation of the PzKpfW 2000 tank project, budget decisions, data of Soviet ammunition becoming available to NATO, appearance of the T-90, etc.) lead Germany to change the configuration "German model" of the Leopard 2A5, to also include "C" and "D-1" generation internal armor arrays. As a cost-cutting or weight-saving measure these changes to the configuration also required to drop the add-on armor modules for the turret roof and hull, whcih are part of the "German model" in the Swedish presentation by R L.

Hull add-on was definitely for cost saving reasons, roof seems to be a deliberate choice as the Germans don't seem to like the roof add-on and how much it increases the profile (atleast two German crewmen told me this was a general consensus among crews).

To me it seems like the Swedish version(prototype) still used atleast B tech turret, just with different wedges and perhaps the hull too, the wedges add something like 700-800mm LOS to the front turret while also almost doubling the effectiveness, so it stays around 0.5 LOS efficiency which doesn't seem like they used anything other than base B armour, I would expect higher values if some other base armour was used.

Those wedges seem pretty much an ideal solution for KE threats considering the massive LOS and rather simple nature, I think the effectiveness of them would increase almost exponentially with increasing base armour effectiveness.

Basically: I think it's quite likely the 800-850mm number was "only" B pakette + the new wedges (would be cheaper than also using even more expensive base armour).

Mostly just speculation but I'm basing it off the German prototype sent to Sweden already reaching 700-820mm on the turret face and those values lining up quite nicely with the chart they also provided.

4 hours ago, SH_MM said:

The graph shows five different colors, but there are five different armor technologies with multiple possible combinations options. I think we can agree that the purple/pink graph shows the "B" armor package, while the red graph shows the "C" armor package; so if yellow shows "B" + "D-2", where is the graph is the "D-1" generation armor package and where is "D-3". Is the blue area the "D-3" armor kit ontop of the "B" armor package or the "D-1" or "D-2" add-on kit on the "C" generation base armor? And what does the green graph show, "D-1" base armor plus "D-2" or "D-3" add-ons or maybe the "B" or "C" oackge with the "D-3" add-on modules?

Exactly what I was getting confused about, my theory is that D-1 could refer to a different add-on such as the roof and thus would be pointless to represent for a frontal attack and it's also the main reason for my suspicion of a 2A4 with "D" tech armour.

D-3 could very well be the add-ons used by the Strv 122 proto.

I don't know frankly and I've been debating this with friends for quite some time, it's also why I very much appreciate the continued discussion :D.

I think the green graph represents the Strv 122 prototype considering only about 30% is below 700mm protection (LFP is roughly 20% of the frontal profile and turret roof 9%, both of these I doubt you can armour past 700mm without adding too much extra weight) so that's either B pakette + D-3 add-ons, assuming D-3 is better than D-2. 

Blue could represent B pakette + D-1 + D-2 or C pakette + D-1/D-2, but I don't know and I doubt we'll know without asking someone involved with the trials (perhaps Lindström can be contacted?).

I agree with red probably representing C and pink representing B, yellow we also have a good candidate for but the rest is pure conjecture honestly.
Still fun to talk about though.

4 hours ago, SH_MM said:

I think it seems clear that the Stridsvagn 122 is equal to the green graph based on the statement that it meet the required levels of protection at more than 70% of the places and that its hull armor managed to stop the 120 mm APFSDS round with 700 mm penetration. As I believe that the Stridsvagn 122 was made with the most advanced base armor available at the time (D-1), that would leaave the blue graph to show the "C" technology base armor + unknown add-on.

Possible as well.

4 hours ago, SH_MM said:

It seems you misunderstood me to some extend, I never said, that the Leopard 2A4 from 1991 with (what I believe would be) "D-1" armor would provide a higher level of protection than the KVT ("B" baseline protection + "D-2" modules); that alone has more than 700 mm equivalent turret armor protection against KE, which would be physically impossble with the Leopard 2A4's armor thickness. I'd expect it to fall between the yellow and the red graph.

Yeah, sorry, that is the most likely option which is why I find it suspicous to be missing from the graph.

4 hours ago, SH_MM said:

I don't think there was any add-on armor in these armor tests. It was one steel plate, one composite armor module, two steel plates and a few other layers. Unless the add-on armor was somehow capable of stopping the LKE1 APFSDS by itself, I would have expected there to be two composite armor modules (one for the add-on armor and one for the base armor) in such a test.

In that case I agree, probably wasn't an add-on.

4 hours ago, SH_MM said:

The Panzer 87 with Swiss 140 mm smoothbore gun is fitted with armor made for the Panzer 87 Werterhaltung program of 2006. Research and development for this armor was started by the company RUAG (owned by the Swiss government) in 1999. It has no relation to what Germany was offering in the 1990s and wouldn't have been tested against the LKE1 APFSDS.

ohhhh, thanks! 
I always wondered why it looked relatively modern (clean) without some kind of restoration having been done to it.

4 hours ago, SH_MM said:

Thanks. These are great photographs, I've seen people making armor thickness estimates for the M1(A1/A2) Abrams for years, but nobody managed to make any actual photographs. Seems that I've understimated the armor thickness, but that was a result of the backplate. The measurement from the outside (where the backplate is not fully included) it shows a thickness of ~34-35 inches (860-890 mm).

 

So the M1A1/A2 have the same armor thickness at normal (no slope), that the original M1 Abrams had with slope.

It certainly doesn't help there's a couple of people that always make crazy claims for the M1 series (and most "normal" people believe these guys).

I always thought it would be atleast about leo 2 level but didn't know for sure, so when one of my friends said he was working on a restoration in this museum I jumped on the chance to ask him :).

I still want some better pics as it would definitely help to combine both inside measurements to outside measurements.

4 hours ago, SH_MM said:

Well, the Swedes got 50% protection mostly as a result of weakspots (gun mantlet, turret ring, roof) and including the turret side armor.

True, side effect (probably intended) of their simulation I guess.

4 hours ago, SH_MM said:

Only the turret frontal cheeks are meant to protect against APFSDS rounds with 600 mm penetration at the 30° arc. The turret side armor protects only against 480 mm KE along a 20° arc (although it seems that the whole crew compartment is located behind the frontal cheeks when seen at 20° angle from the turret centerline).

Yep, that's one advantage of such a spacious and wide armour design I guess.

If you compare the leclerc, leo 2 and M1A2 you can still see just how small the actual crew area is on the leo 2, it's even smaller than on the leclerc!

4 hours ago, SH_MM said:

Patent DE3508053A1

Thanks!
I have been looking on that site but clearly my search skillz weren't quite up to par .

17 hours ago, David Moyes said:

Even without a gun upgrade Rheinmetall is almost certainly going to win.
The only thing that BAE's bid has going for it is that General Dynamics would do the actual work. Offering Iron Fist is bizarre as the UK has two separate APS programmes going and any acquisition would go through them.
No gun upgrade seems like a cynical way to lock the Army into BAE's munitions ecosystem.

Recently the MOD has signed contracts with several companies to test their ammunition in preparation for BAE's sole supplier deal ending in 2023. Rheinmetall is one of them, specifically for artillery.

Offering free guns in exchange for an exclusive supply deal would be smart.

Well, apparently they're going to go with BAE and if they do that, that means any future procurement will also be given to BAE.

Rheinmetall's upgrade wasn't just a gun either, it was quite a bit more but I guess we'll see when they finally decide.

10 hours ago, Jägerlein said:

I...doubt, thar Hilmes mixed up something in this matter. He did a bit more than "just writing about" the Leopard 2 upgrades.

I know he's been "involved" with some of the projects, but he's still human and can make mistakes.

But if he's right that means that the armour is better than in the Swedish tests...

1 hour ago, SH_MM said:

Both Rolf Hilmes and Frank Lobitz specifically mention that the base armor of the Leopard 2A5 was replaced with new inserts in "D"  technology. During the Leopard 2A5 upgrade process, the turret structure of the Leopard 2A4 is cut open and new armor inserts in "D" technology are installed. For the last batch of Leopard 2A4 tanks Lobitz mention that the tank featured "improved armor protection" and at another place that it can be identified by the new light side skirts in "D" technology... adding one and one together and this leads to the last Leopard 2A4 featuring "D" technology armor.

Hm, so instead of continuing to use "B" tech, they replaced it with a better armour solution that gives even more protection for the base armour alone and adding wedges ontop of that?

Seems quite expensive to me, maybe the author mixed up "integrated" and "add-on", but then again, they might as well replace all the armour if they're going to refurbish and rework those turrets anyway...

1 hour ago, SH_MM said:

According to Michael Scheibert, author for the (nowadays defunct) Waffen-Arsenal book series, the (first) Leopard 2A4 armor upgrade was weight neutral, i.e. there was no weight gain or loss (although I personally believe that there was some minor difference).

 

The 56.6 tonnes figure is rarely used, but it has appeared in a quite a few articles on the Leopard 2A4 and a number of press releases (for example the company Ingenieurbüro Deisenroth stated in an article about the reveal of the Leopard 2 Evolution upgrade with AMAP armor, that the Leopard 2A4 used as basis for the demonstrator had originally a combat weight of 56.6 tonnes, which had to be lowered by removing the side skirts before the Evolution kit could be added to remain in the desired 60 tonnes weight limit).

It isn't actually confirmed that this weight figure is related to the extremely rare Leopard 2A4 with "D" technology armor (only 75 made for the Bundeswehr of which only 1 still exists) or not - but unless the literature is wrong and the version with "C" armor is actually heavier than 55.15 tonnes, the 56.6 tonnes figure has to refer to the latest version by the method of elimination. In theory the Leopard 2A4 with "D" technology armor might also be heavier than 56.6 tonnes, I've never seen an actual weight value specifically mentioning that it belongs to the 75 tanks of the eight production batch.

So, they went from 350mm (30° offset) to 420mm while not adding any weight, that would require replacing a lot of the plates and not adding anything more, friend of mine suggests that perhaps they moved the array back a bit (while making it denser) and left a larger airgap behind the coverplate, combined with ceramics in the mix that would make it possible.

I'm still quite skeptical of a 2A4 with D tech, it seems like an awful lot of effort for only 75 tanks.

1 hour ago, SH_MM said:

The Soviets adopted new armor arrays (mainly for the hulls of their tanks) at a much steadier rate, e.g. the T-72B was built with three different armor arrays within a period of just 5 years. West-Germany adopted the new (and more protective) Leopard 1A3 turret just 13 months after the new turret for the Leopard 1A2 had entered production. The M1IP version of the Abrams entered production four years after the M1 Abrams, yet it featured improved armor and a longer turret. So three years for a new Leopard 2 armor package developed at the height of the Cold War doesn't seem implausible.

True, but they were already in the process of developing the wedges and even had them by 1991, personally I don't see the point as even D tech would be quite expensive because of the materials.

Anyhow, I'll consider it a possibility.
 

2 hours ago, SH_MM said:

This image is from a set of documents delivered by Krauss-Maffei to Sweden and leaked as part of R. L.'s presentations.  It shows the references for the armor packages (although it doesn't mention wether this means that the armor protection is comparable to the Soviet tanks or meant to resist rounds fired by these Soviet tanks). The 3rd generation armor package (which would be "D" technology based on the German naming scheme) was adopted in 1991, yet the Leopard 2A5 entered service in 1995. It was meant to compare to the (armor or firepower of the) FST (Future Soviet Tank), which was expected to enter service in the 1990s and feature a next-generation gun (various different calibers including 125 mm, 130 mm, 135 mm and 152 mm have been mentioned in different articles over the years).

It appears that in fact both new armor packages for the Leopard 2A4 and the Leopard 2A5 were developed after the BMVg (German MoD) requested a higher level of protection back in 1984, which kickstarted the Leopard 2A5 development (a first prototype with add-on armor looking similar to the 2A5 being tested in 1986).

 

Please note that there are three versions of "D" technology armor (D-1, D-2 and D-3). The Leopard 2A4 could use "D-1" inserts, while the Leopard 2A5 made for Sweden could feature "D-2" or "D-3" inserts. I don't think that Krauss-Maffei would choose this "table format" for displaying armor packages, if the "D" technology armor was only available as add-on modules.

Note that the line "Pakete" (armor inserts) also contains fields for the three types of "D" generation armor. Also note that "Technologie-Kombination" means "technology combination" (implying that all types of add-on armor modules and base armor can be easily combined).

 

From what I recall and what I think seems to be the case is that the TVM delivered to Sweden for the trials had B pakette and D-2 add-on, the Swedes also mention they made another package based on IBDs design which was superior, from what I can tell the base armour didn't differ but the add-on did.

TVM seems to have flatter add-ons and what ended up as the Strv had more tapered add-ons.

So the question is wether or not they had different internal armour on the actual Strv 122 as opposed to the prototype or if the prototype already had that and what the actual combination on both is.

I'll just put down what I know and suspect:

German prototypes sent to Sweden: B pakette + D-2 add-on

Swedish prototype in trials: B pakette + D-3 add-on?

German 2A5: C/D hulls, only "D" side add-on, B turrets with swapped out inserts to D tech, D-3 wedges as add-on?

Swedish Strv 122: B pakette + D-3 add-on maybe changed B turrets to D inserts?

Now, we know the protection for what the Swedes had, though we don't know the exact combination they used, if they did indeed use B pakette with some D add-on that was better than the German proto, that means if the German and Swedish 2A5s use different internal armour on the turret, the protection afforded would be substantially higher?

From 800-850mm to xxxx-xxxxmm?

Man, this is a whole can of worms.....

One thing I have to point out is how on this graph we can see that the yellow graph matches the combination B pakette + D-2 add-on:

If red is supposed to represent C tech (which my estimation in the leo 2 thread was based off and which is apparently quite close to the numbers you've posted), there's no other graph that could represent a "D" pakette or base armour, as there's no way a "D" base armour is going to beat the "B" base armour + add-on.

This is why I just don't see "D" technology being used for base armour, it's possible but without having read those references from those known German authors I'm hesitant, (even with references though, they could still be wrong or have mixed some stuff up, it wouldn't be the first time).

That kinda leads me into the next question: can you tell me in what books they mention these things?
I've been trying to find books specifically on the leopard 2 from both Krapke and Rolf Hilmes but most of them are paperbacks that are being sold in different countries or have been sold out, I also can't find any ebooks (free or paid) :/.

Specifically referring to the newer books and more in-depth ones, I've got the Waffen arsenal one on the leopard 2A5 but that doesn't go that far in-depth.

2 hours ago, SH_MM said:

It is indeed a very odd situation, I can understand your skepticism. I probably also wouldn't believe anyone saying that he has a classified source showing that a tank had a much higher level of protection than other people consider plausible. I can only say what I have seen and what I've heard.

 

I don't think the M1A2 still has the same level of hull protection as the initial M1 Abrams. The British stated that the later has a protection was only 320 mm against kinetic energy penetrators (from the front?), while the M1A2 offered to Sweden reached 350 mm along the frontal arc (it could be a bit more directly at the frontal cavity, given that the weakest sectioon of the frontal arc is probably the side skirt area at 25-30°). The hull armor was upgraded with the variants M1A1/M1IP (there were at least weight demonstrators welded to the hull front of the M1E1). The hull armor of the Leopard 2 can be upgraded more easily, in the original models there even was a hatch to access the armor inserts (which was shut via bolts), only during the upgrade to the Leopard 2A4 this was shut by welding. In a Canadian Army maintenance facility, they have opened the hull armor cavity of a Leopard 2A4 with "B" armor package (the edges of the plates inside however are oddly soft compared to the rest of the photograph, they might have been added with photoshop):

True, an M1A2 crewman (yeah, not the most reliable source) did tell me they changed the armour, didn't tell me they upgraded the KE protection though, he was ofcourse being quite vague.

So they probably did change the armour over time, what I meant was that they didn't seem to add more armour there which could explain a weight difference, atleast not a big one.

As for that picture, I agree it's a bit dubious but the possibility for replacing armour quite quickly is definitely a thing from what I can tell, so I guess it's possible that armour was changed without too much hassle (or expense).

7 hours ago, SH_MM said:

As for the weight increase and the corresponding increase in armor protection, there are multiple factors to consider. First of all, there are differences between both tanks, that shouldn't be ignored. The Leopard 2A4's turret front is about 15% smaller than that of the M1A1 HA, thus for an equal increase in armor weight, the Leopard 2A4 would require only a weight gain of 2.55 tonnes. The 1.45 tonnes that the Leopard 2A4 with "D" technology might be heavier (assuming the 56.6 tonnes figure is correct) than the earlier variants seems to fall a bit short of that, but the question remains wether a M1A1 has the same amount of (turret) armor weight per volume as the Leopard 2A4 with "B" or "C" technology armor. Given the larger frontal profile and the extensive side armor, it seems possible that the Leopard 2A4 has actually denser armor to start with (at least this was the case when comparing the Leopard 2 to the M1 Abrams). Another factor is the side armor: the Leopard 2A4 from 1991 features new light side skirts made of high-hardness steel, which supposedly provide the same protection level at a slightly smaller thickness than the previous type. Also there are unconfirmed rumors about the side armor at the frontal section being different; some Danish soldier claimed that the Leopard 2A5DK has thicker steel side armor than the Strv 122, which at least partly might be confirmed by the fact, that the latter had a slightly lower protection level against RPGs hitting at 90° angle than the Leopard 2 KVT during the Swedish tests. Compared to the M1A2, the Leopard 2A4 has a much larger gun mantlet, which probably wouldn't be able to reach the same protection level (and probably would also have a much lower weight than the main armor).

True, the tanks are quite different and the leo 2 is notably smaller in terms of volume that needs protecting so it can afford more armour for the same weight, it's just odd that a late 2A4 (wether that's C or D tech) would reach equal frontal protection, or atleast close to it, as an M1A2 while also weighing a good 5-6t less.

In any case: I'm open to different possibilities if there's enough evidence, that chart coming from German sources is probably enough to prove it's not BS and talks about the armour generations/combinations.

7 hours ago, SH_MM said:

The makers of the video game War Thunder measured the thickness of an early-model M1 Abrams using tape measures and an ultrasonic probe.They concluded that the backplate of the hull armor is 101 mm thick (excluding slope), which seems to be quite a bit. The Leopard 2 - at least on the turret - uses what seems to be a 40-60 mm thick backplate, thus more weight can be invested into special armor with a higher mass efficiency. Maybe the turret armor also follows this layout, at least the people from the War Thunder developer claim that the size of the special armor cavity is only 19.5 inches (I believe without slope). Assuming that the turret backplate is also 101 mm thick and knowing that the measured thickness of the turret frontplate was 38.1 mm, the total thickness of the M1 turret armor would be 634 mm or ~732 mm LOS from the front, which falls into the range of estimated armor thickness from various internet users.

 

It is worth noting that the M1A2 turret in Sweden provided 600 mm protection vs APFSDS rounds along the frontal arc, the armor tested in Germany was however simulating a hit directly from the front (otherwise the armor would be way too thick). So there still could be a ~10% difference in armor protection in favor of the M1A2 (esp. considering that the armor package with DU might be slightly better).

Are you talking about this "D" tech array?
If so, would it be possible even plausible that it is indeed 800mm not taking into account angle because of a flat add-on ?
Like on the leopard 2 with the 140mm:

7 hours ago, SH_MM said:

There is no doubt that the armor array survived a hit by a LKE1 APFSDS without being fully penetrated, which is why there are a few possible options:

1. The armor might not be identical to the one adopted on the Leopard 2A4 production model of 1991 - however the armor was tested before the DM43 APFSDS was type qualified (which IIRC happened in 1994 or 1996) and it was offered as an upgrade option for users of the Leopard 2A4 with "B" generation armor, so that doesn't seem to be the most likely option.
2. The Leopard 2A4 from 1991 might have a larger combat weight than assumed; it is a really rare variant and no user of the Leopard 2A4 seems to have ever upgraded their 2A4s to a version with "C" or "D" armor package (at least the side skirts have remained identical). 
3. The LKE1 APFSDS being a prototype mgith mean that it actually had a lower level of armor penetration than the DM43 APFSDS - but it probably was always superior to the DM33 APFSDS it was meant to replace (which apparently has ~480 mm at 2,000 m penetration).
4. The Leopard 2A4 armor from 1991 could be highly optimized against KE, potentially sacrificing relative protection vs HEAT. The rumored inclusion of tungsten and titanium would support this, as this would be similar to the DU armor of the M1A2 (at least the SEP features titanium within its armor array).

Yeah, those do seem likely or atleast possible.

7 hours ago, SH_MM said:

I dont think that is very accurate. I've seen a wide range of estimations for the M1A2's turret front (as low as "below 800 mm" and as high as 1,100 mm), yet no accurate measurements have ever been made. The M1A2 models use the same turret dimensions introduced with the M1IP in 1984; at this time 940 mm physical thickness would have been more than any other contemporary tank (T-72B, T-80U, Leopard 2 and Challenger 1 all having 800-870 mm physical thickness along the line-of-sight at most).

How did you estimate the thickness? Did you keep in mind that the slope of the turret cheeks is assymetrical (left turret cheek is sloped more than the right).

Here's one of the pictures he took from the front left corner of the armour, it's 733mm thick:

However, we had more pictures and he was actually measuring it and talking to me at the same time, I'll see if I can get a hang of him because some of the pictures are on a different discord server I don't have access to.

When he measured parallel to the gun (IIRC left side like on the pic) he got 78" from the front turret face to the loader's hatch and he measured on the inside 41" from the turret armour to the loader's hatch (same spot), that leaves 37" give or take a little bit which equals about 940mm.

Unfortunately he didn't take pics of all the measurements as he was supposed to be working on the exhibit, but I've asked him to redo them, so I might update you on it when he gives me more pics.

But yes, it does seem to be pretty much ~940mm give or take a bit.

Even on that last pic you can see it go from roughly 46" to 82".

7 hours ago, SH_MM said:

Also don't forget that this is 600 mm along the frontal arc, so it is achieved by the unsloped armor package already. While the M1A2 Abrams has a combat weight of 62.5 tonnes, the armor weight was likely not increased over the M1A1 HA (at 61.8 tonnes; the M1A2 adds a lot of additional parts to the tank that might explain the weight difference); this is about 3 tonnes heavier than the M1A1 when both tanks are fitted with the T158 tracks.

Yeah, though it didn't change much in terms of protection between the Swedish M1A2 and the armour values given by the US, (Swedes got to 50% protection for 600mm KE at 20° offset, US values were 600mm across 60°? arc).

7 hours ago, SH_MM said:

There have been several statements from various sources hinting that there are more armor generations. When the Leopard 2A7 entered service with the German army, Jane's Defence Weekly stated that it is being protected by a "new generation" of armor in the turret and hull. According to Polish news agencies, Rheinmetall claims that the Leopard 2 turret with AMAP armor provides more protection than the Leopard 2A5 turret, but equal protection to the Leopard 2A7. There are also some mentions about certain exported tanks featuring "improved armor", although it is never mentioned what the point of reference is.

 

It seems rather reasonable to assume that after the "D" technology armor from 1991/1995, armor development didn't cease. The Leopard 2A7V prototype presented at Eurosatory 2016 for example features a different hull add-on armor kit compared to the Stridsvagn 122 (similar thickness, but the size and location of the mounting screws is different).

Makes sense that they wouldn't cease with development, though I'm always wary of news agencies, bolt/screw changes could very well be a logistics thing, though it does suggest a change.

7 hours ago, SH_MM said:

No, the entire armor array that stopped the LKE1 APFSDS was about 800 mm thick: 100 mm soft steel, 500 mm special armor, two layers of 100 mm soft steel. The APFSDS reached the third steel plate, so it defeated more than 700 mm armor.

 

The Leopard 2 is said to feature some extremely expensive steel types, which provide high levels of protection. For example according to the company that provides the very few cast steel elements for the Leopard 2 tank, the cast steel has a hardness of  350-380 HB on the initial model and 380-420 HB on the Leopard 2A4 and Leopard 2A5. The turret shell of the initial model was made of HFX 130 steel with an average hardess of 380 HB; it seems likely that the Leopard 2A4 tanks with "C" and "D" generation armor use different steel with a hardness of more than 400 HB (note that on the photograph showing the Leopard 2A4 turrets being upgraded to the 2A5 standard, the outer steel plate of the turret structure of one turret is missing).

 

According to an article published in the International Symposium on Ballistics by a German scients working for the Franco-German Institute in Saint-Louis (which is focused on military research), special combinations of high-hardness steel plates (probably as DHS or THS) can reach a thickness efficiency of 1.8 compared to RHS. DHS can reach a thickness efficiency of 1.78 accoridng to Hazell's Armour. Jane's Defence Weekly reported during the 1990s (or at least it claimed to have reported), that the Leclerc (contemporary to the Leopard 2A4 with "D" tech armor and the Leopard 2A5) uses THS with a thickness efficiency of 1.81 as part of its armor array. However DHS and THS are very expensive.

Heavy metal alloys such as DU and WHA have also both shown a thickness efficiency larger than 1.

 

Another factor is that the LKE1 APFSDS was still in development, the performance figure is estimated based on the actual 120 mm DM43 that was IIRC type-qualified in 1994 or 1996 (this also is a nice way to see that the armor array was tested in the early 1990s).

OK, that sounds a lot more reasonable, I do know that Germany quite likes their steels or metals so I agree that they could achieve quite high thickness efficiencies.

7 hours ago, SH_MM said:

The Leopard 2A5 requires swapping out armor inserts aswell, while requiring a modification of the armor layout at the gunner's sight, new hooks for the add-on armor modules and hinges for the new mantlet armor modules, a modification of the gun (with different trunion), modifying the optical channels of the sights and numerous changes not related to armor protection.

True, but they might've only changed the armour they needed, regardless I want more info .

On another note: since you've pointed me into the direction for DM13 APFSDS and it's patents, would you mind telling me where that DM33 patent picture comes from?

2 hours ago, SH_MM said:

 

It seems that the British documents use values for protection along the full 60° frontal arc.

 

The minimum thickness of the Leopard 2 turret cheek armor along the frontal arc is roughly 660 mm.

860/660*350 = 456 mm

860/660*420 = 547 mm

 

That matches the current interpretation of this graph from the Swedish documents:

 

 

Furthmore there is the statement about the M1A1 HA's DU armor providing 15° more protection than the Dorchester armor of the Challenger 2. Given that the former is believed to provide 600 mm protection vs KE along the frontal arc based on the Swedish documents (or about 660 mm from straight on assuming that the armor efficiency stays the same regardless of horizontal slope), this would put the Challenger 2 at 510 mm (560 mm head-on) vs KE. The protection requirement for the turret was armor equivalent to 500 mm steel vs KEPs (along the frontal arc?).

 

Even more so, the Brits believed the M1 Abrams to feature turret armor providing 340 mm equivalent protection vs KE along the frontal arc. That would be equivalent to 392 mm vs KE from head-on. A CIA document puts the M1 Abrams' turret at 400 mm vs KE.

 

 

Interesting, I think in the case of the Challenger it doesn't refer to added protection equivalent but actual LOS thickness of the entire package.

As for the number of the leopard 2, B seems more or less correct, not sure about C though, it's definitely interesting that it keeps coming back that C tech had this much added over the first variants, the weight increase doesn't seem like it would be enough, perhaps they managed this by using very "light" materials such as ceramics and replacing some steel with lighter alternatives?

Maybe they replaced the entire array and made it more efficient with higher hardness or something?

As for Challenger 2, it seems that in the Hellenic tank trials the tank was critisised for it's poor hull protection and lack of roof protection, similar to the Leclerc in terms of protection, so ~550 wouldn't seem too far off, it's definitely worse than the M1A2 and leopard 2A5 as suggested.

I still need to find the original magazine where they talk about the trials though.

3 hours ago, SH_MM said:

According to different German authors (Rolf Hilmes, W. Spielberger, Frank Lobitz) the base armor used on the last batches of the Leopard 2A4 and on the Leopard 2A5 is based on "D" technology. The original armor package for the Leopard 2 (in "B" technology) remained in production until the 96th vehicle of the sixth production batch; starting with the 97th vehicle of the sixth batch, the new armor kit in "C" technology was used. The original Leopard 2A5 prototype (the KVT) was based on a hull made in 1987 as part of the fifth production batch, hence it was  made with the original base armor package, only the add-on parts made use of newer technology.

Yeah, thing is, they don't specify the base armour itself being "D tech" (atleast as far as I could tell).

What seems to be the case is that C tech was a base armour technology but D tech were exclusively add-ons like those in that picture you posted of the 2A4, the parts on that which I think are "D tech" are those add-ons above the ballistic skirts and the normal skirts, both of these you can also see on the 2A5 which I think is actually what they meant with the "third generation", it was after all a KWS initially and was only called 2A5 when it finally entered service.

Reason why I think that is because creating another "generation" or major improvement in base armour only 3 years after the last and while also developing far superior add-ons that improve upon the base armour with rather minimal weight increases just seems wasteful and pointless.

At the same time I've never seen a third "weight" for a leopard 2A4 that's higher than 56t, which is what would be necessary for an increase to beyond 600mm.
 

Basically: if there is such a thing as "D tech" it's not going to be that different in terms of actual protection unless the weight is substantially higher, just for comparison: M1A2 "only" reaches ~620mm or so on the front turret (supposedly the US tested against their best armour protection, M1A1HA/HC, in the states and gave the Swedes that info, which would be that one page with the top down view) and weighs 62.5t while having the same hull protection as the initial M1.

A friend of mine measured the distance between the start of the turret armour and the end on the M1A1 in that new US museum that recently opened to the public (the one that the Chieftain did a video on) and we figured out that the LOS thickness is ~940mm including front and backplate, so reaching 620mm out of 940mm isn't crazy, especially given teh weight of 62.5t, but for the leopard 2A4 to do the same with less LOS thickness and less weight, ontop of also increasing hull protection just seems fishy to me.

That's also why I'm dubious of C tech reaching higher than 500mm on the turret cheeks with barely a 850kg weight increase from B tech to C tech, I mean, the M1A2 focussed all if the armour upgrades on the front turret and that still increased the weight at the very least 3t just going from M1A1 to M1A2.

3 hours ago, SH_MM said:

The production model of the Leopard 2A5 tanks for the German army was created by mating Leopard 2A4 hulls from the last production batches (with armor in "C" or "D" technology) with turrets from the earliest production batches. The old turrets are used, because they require extensive rework during which the base armor is replaced with new modules in "D" technology.

They do require extensive reworking, but it seems only the area around the gunsight, so switching out the entire armour for a new one is possible but I think quite expensive (which Germany was being careful of, unification and such...).

3 hours ago, SH_MM said:

The Leopard 2A7V will be the first German version too feature hull add-on armor modules, although this might be "E" or "F" type armor.

E or F?
Never seen that before, just speculation or do you have a good reason for that?

3 hours ago, SH_MM said:

I haven't seen any texts, but a set of photographs of an armor array being tested. It consists of a thick steel plate, a large box labeled "Sonderpanzerung" (special armor), two further thick steel plates followed by a number of several other plates, some of which appear to be non-metallic. I was told that the thick steel plates have a relatively low hardness, but are used to simulate thinner plates of very high-quality (and very expensive) ballistic steel. There is no external armor module.

In front of the armor array is a sign from the German WTD saying that this array is being tested against the LKE1 APFSDS at a range of 2,000 meters.

Interesting....

3 hours ago, SH_MM said:

The other photos show the three thick steel plates after the armor array was hit: one shows the exterior of all three plates, each showing the marks of the APFSDS penetrator. Another photograph shows the inner side of the three thick steel plates: two of them have been completely penetrated, while the other one has only a dent of the APFSDS penetrator. There is also a ruler/measurement rod, which suggest that the "Sonderpanzerung" is about 500 mm thick only. The steel plates are about 100 mm thick, but supposedly they are made of mild steel; the actual ballistic steel would be some fancy type of high hardness/triple hardness steel providing a much higher level of protection per weigth and thickness.

Hang on, you're saying the entire array is only 500mm?
And it stopped a rod with 600mm of penetration?
So a thickness efficiency of higher than 1.0 with space gaps..... uh.

3 hours ago, SH_MM said:

I actually haven't seen any proof that this armor belongs to the late Leopard 2A4 tank, but I consider the source very trustworthy. This armor was supposedly offered during the early 1990s as a cheap upgrade option to several Leopard 2 users, who didn't want to pay for the more expensive Leopard 2A5 upgrade, which is why I believe this is the "D" technology armor. According to different authors, there are (unconfirmed) rumors about the late Leopard 2A4 armor featuring titanium and tungsten, which might be broadly similar in to the DU armor of the M1A1 HA (at least the M1A2 SEP uses titanium to allow improving the armor protection without increasing the mass of the armor considerably). It is worth noting that AFAIK only the Leopard 2A4 with "D" technology is actually heavier than the Leopard 2A4 with "B" technology, apparently by 1.45 tonnes (at least the weight 56.6 tonnes has been quoted for the late Leopard 2A4). The M1A1 HA upgrade is heavier, but might cover more surface area and might have initially lacked the titanium weight saving measure.

Hm, wouldn't this require replacing the entire array though?
I fail to see how this would be that much cheaper than a 2A5 type conversion, titanium and tungsten are both expensive materials and if this is for all of the special armour, that's quite a lot of material.

I also think that tungsten seems quite counterproductive to use because it's so heavy (then again, the US uses DU, though it might not be entire plates), using titanium is quite plausible but for it to only gain 1.45 tonnes with a substanial protection increase (600mm+) seems too good to be true.

I find it's quite hard to get good weight numbers on the leo 2 though, even KMW lists the 2A4 as 55.1t all the way to 62.5t (probably 2A4M with wedges).

Still, as far as I can find for the M1A1HA all of the extra material was for the turret front, if the 2A4 had it distributed across the 60° arc.... it would need substantially more weight and the M1A1HA isn't light in the first place, quite a bit heavier than the 2A4s.

Quote

As far as I know it should be hollow, at least for the early version of the Leopard 2.

Well, Krapke gives 4290kg with mantlet for the gun and 3100kg without, I'm assuming he's including the gun cradle in this.

This matches that Swedish firing table perfectly.

That's for the 2AV.

11 minutes ago, SH_MM said:

The yellow graph might correspond to the Leopard 2A4 with "D" technology armor (production start in 1991), not the Leopard 2A4 with "C" technology armor (production 1988-1991).

Well, yellow seems to match the leopard 2 "improved" scheme nearly perfectly, for 700mm it shows 30% protected surface which matches the graph on the right, same for the 600mm protection, it's just above 40% for both.

That's only from straight front though.
I don't think D tech was ever a main armour technology, it seems to be exclusively add-ons, I mean, getting 700mm odd protection out of 860mm LOS seems way too much without adding appliqué.

As for C tech, I meant the red graph, it's still too much for the weight difference, but I don't know what else it could correspond with.

15 minutes ago, SH_MM said:

I can say that the late Leopard 2A4 turret front with the latest armor ("D" technology) did survive a direct impact from the LKE1 APFSDS fired from 2,000 m distance without the projectile reaching the inner layers of the armor array. This round was later type-qualified as 120 mm DM43 APFSDS (given its 600 mm penetrator length and 1,740 m/s muzzle velocity, it should be able to penetrate about 600 mm of flat armor at this distance). The sources for this is classified, unfortunatley it cannot be shared without potentially getting some people in trouble.

Hm, does it mention wether or not add-ons were used?

While I consider your statements and such quite reliable, you have to understand I don't want to just assume you're correct without evidence, still thanks for the info :).

(that only makes me even more confused tbh)

12 minutes ago, SH_MM said:

The 120 mm DM53 APFSDS round did not exist at the time of the Swedish tests and certainly wasn't delivered to Sweden. The photograph most likely shows a test projectile made only for the evaluation.

Well, it would've been a prototype if anything, but the similarity is too striking for it to be a coincidence, perhaps it was just a round with the same function and rough dimensions.
 

13 minutes ago, SH_MM said:

The data for the Leopard 2 tanks apparently comes from Krauss-Maffei and likely does not reflect what Sweden was able to test (it would be very odd to let Sweden fire its APFSDS rounds and shaped charges at every possible armor package ever made for the Leopard 2, if they are only interested in the latest one(s)).

If this is true, then I agree, but I don't know for sure.

14 minutes ago, SH_MM said:

The extract from the book regarding Chieftain''s armor already shows that the British underestimated the performance of Soviet rounds, it says that (in 1981) the penetration of the T-72's 125 mm gun was estimated to be 420 mm for steel penetrators and 475 mm for tungsten penetrators point-blank at normal (aka 0 meters, 90° impact angle). The United States also underestimated the performance of the Soviet 125 mm gun and ammunition, one could say they did that to an even greater extent.

Yep, it seems only Germany fully realised the 125mm potential (atleast looking at the Krapke threat diagram) although the leo 1 part probably isn't correct.

7 minutes ago, SH_MM said:

leverbara systemets - elevation system,

Vapensköld - gun shield (mantlet),

Hylskorg - basket for the propellant stubs,

Krugasejektor - fume extractor,

Backstycke - back part of gun (breech block, etc.),

Kil - wedge lock,

Vappenvagga - gun cradle,

Framförare - the opposing actor to the recoil brake (don't know what the exact term is in English),

Rekylbrom - recoil brake

 

The Vappenvagge should include the trunion, but also the other parts of the cradle, at least if the definition is identical to the German one. I.e. everything orange:

Thanks, yeah I also confirmed it with my Swedish friend, though he isn't part of the military in any way so he didn't know 100%.

That the "Vappenvagge" also includes some smaller other bits makes sense and would explain the rather high weight, though it does seem like the "trunnion" or gun cradle is indeed atleast more armoured than the proposed 25 + 25 like on the leopard 2K diagram.
Makes sense as I've talked to numerous leo 2 crew some of which told me they "tapped" on the trunnion and thought it didn't sound hollow.

And yeah, these guys do actually know more than the average person as they're very much interested in this kind of thing. 

10 minutes ago, SH_MM said:

AFAIK it is all calculated based on the LOS thickness at these tangles and the performance data delivered by the tank manufacturers without any simulation of materials.

Ah, that would make sense yeah, I guess this is the simplest solution and probably the most likely.

11 minutes ago, SH_MM said:

The graphs on this page are not from Sweden, but part of the documents delivered by Germany (that's why the description of the table is in German). The data should be valid for the complete vehicle surface at the relevant angles.

Oh, interesting, I was wondering why they seemed to look more German than Swedish (admittedly, they're quite similar languages).

So, if it doesn't take into account the "inert" parts that would be more reasonable, I'm still very confused as to the red graph (in the middle), it doesn't seem to portray C tech as the values are incredibly high for such a small weight difference (55.15t -> 56t).

Yellow seems to match the graph on the right, so B pakette + D-2 wedges, but I'm curious as to the other ones.... perhaps a "C tech" pakette + wedges? Or D-1 and D-2?....

We don't have a lot to go on, I'm hoping you have more info on it so we can figure it out with a bit less speculation :D.

On 11/27/2018 at 1:23 PM, SH_MM said:

The Challenger 1 was designed to reach a protection level of 500 mm vs KE on turret and 275 mm vs KE on the upper hull front, but according to a footnote in the same book reached only 480 mm vs KE on the turret and 340 mm vs KE on the hull.

Well, yes and no.

Challenger 1 in this case refers to the Challenger 1 and not Challenger 1 Mk 1 as a lot of people seem to think.

They say it's only able to stop T-72 tank rounds at ranges above 1km, now they supposedly rated the 125mm at 460mm DU and later in 1981 they rated the tungsten 125mm at 475mm.

I do have to point out how this table seems quite inaccurate or atleast inconsistent, even if it just refers to the hull armour, both the T-64 and T-72 reach higher than 270-290mm.

So, personally I'd put the turret more at around 470mm or so and the hull at 325 against WP ammo, against long rods.... it's going to be less than this.
 

On 11/27/2018 at 1:23 PM, SH_MM said:

The Leopard 2A4 (with Type B armor) was rejected for its poor armor, worse than the Chieftain with Stillbrew vs KE.

I've noticed that as well, they for some reason think the 2A4 was poorer armoured than the stillbrew chieftain, something I find quite funny.
The hull is obviously superior on the leo 2 and the turret especially in the frontal 60° is also superior or at the very least equal.
 

According to this page:

The stillbrew package in 1985 only managed to resist L23A1 (I assume it's L23A1, L23 is also possible) only at 1km, penetration for L23A1 according to another book (maybe the same one, but I think it's about the Challenger 1) is around 460mm.

So, ~450mm of KE protection at the tested spots isn't far off let alone superior to the 2A4's ~430mm which was achieved by firing what looks to be DM53 at it.

Right hand one was used for turret testing according to that slide and it looks an awful lot like DM53, the left one looks like DM33.

So, considering L23A1 is notably worse than DM53, I think it's safe to say it would  do worse against a 2A4 turret than DM53 and the protection given by the armour would "increase" as a result.
 

All of that is from a stricly frontal attack, the sides of a 2A4 are also fitted with spaced armour and the LOS of it would reach around 620-640mm if hit at a 30° angle.

The Stillbrew chieftain on the other hand ranges from ~160mm at the front corners to ~86mm at the flat turret sides, neither of these seem really better than what the 2A4 has to offer.

I also have to point out that it seems the Brits didn't realise that long rods actually perform better at angles than against flat armour, so to the left of the gun (from our POV) is only 120mm cast + ~60mm rubber + 125mm steel at 60°, which against a long rod won't perform as well as the right side which is 150mm cast + 60mm rubber + 150-215mm steel.

So in effect, the left side of the turret is quite a bit weaker than the right hand side despite probably having similar LOS values.

That's also why I consider the statement in the outer right column of that picture to be quite naive:
Reposted image for easier reading:

Quote

With it varying from 480mm to 540mm; however the final design was considered sufficient to stand a good chance of resisting the Soviet successor 125mm round (tungsten monobloc and sheathed staballoy, which was postulated as being able to penetrate around 530mm point blank).

So, despite their own round already penetrating it from 1km or so and the protection being quite inconsistent, they think it'll stop future 125mm long rod ammo?

L23A1 is already a little bit worse than 120mm DM23 in terms of raw performance, 3BM32 and 3BM42 I highly doubt will have any issue with this armour at most combat ranges.

So either they didn't think the Soviets couldn't make better ammo than they did, or they didn't understand that long rods perform better against sloped armour and LOS being equal doesn't translate to the afforded protection being equal.

Either case seems likely IMO, especially considering their track record of underestimating/misjudging Soviet ammunition.

Anyway, I think we need to stay critical even of their official documents as they seem to be wrong or inconsistent in quite a few cases.

3 minutes ago, TokyoMorose said:

TL;DR - The Brits judged purely by amount of frontal area ammo is stowed in, irrespective of how armored or safe that area is. By that logic, T-72s have the safest ammo stowage of any modern tank...

Yup, just like their preferance for not having a unitary sight, they seem to often come to the wrong practical conclusions.

1 hour ago, SH_MM said:

"12 cm kanon strv 121/122 - Skjuttabeller" by the Försvarets Materielverk (i.e. the official firing tables and technical manual of the 120 mm gun of the Swedish army). The title of the document suggests that the data would be largely valid for both the Stridsvagn 121 (Leopard 2A4) and the Stridsvagn 122 (Leopard 2A5), but the drawings and total weight suggests that the weight data is taken from the Stridsvagn 122.

 

But the 110 kg was wrong, I read the value from the wrong column. It might be a lot heavier.

Oh, that tabel in the "documents for the documents god" thread?

Quote

Eleverbara systemets vikt ............................................................................................. 1165 kg
Vapensköld ................................................................................................................................ 595 kg
Hylskorg .......................................................................................................................................... 24 kg
Eldrörsskydd ............................................................................................................................ 29,5 kg
Krugasejektor .......................................................................................................................... 12,5 kg
Bakstycke vikt ......................................................................................................................... 580 kg
Kil vikt ........................................................................................................................................... 110 kg
Vapenvagga vikt ..................................................................................................................... 595 kg
Framförare vikt........................................................................................................................... 36 kg
Rekylbrom vikt........................................................................................................................... 63 kg

Interesting, I completely forgot about this, from my (limited) understanding of Swedish, "Vapensköld" I think means mantlet, "Vapenvagga" supposedly (asked another person too) means guncradle, I'm asking a Swedish friend of mine to confirm though.
 

1 hour ago, SH_MM said:

The AVDS-1790 was a much older design that was only used for the M60, because the United States originally focused on different projects (mainly the T95 medium tank) and only went back to using the AVDS (which already had been used in slightly different versions in the M47 and M48 Patton tanks) after these ended unsuccessful. The overall situation is a bit worse considering that the United States were using SAE gross horsepower at the time (i.e. they measured the maximum possible power output in the baseline configuration by excluding any factors such as cooling fans, that would result in a loss of power), while Germany was using DIN-PS according to the standard DIN 70020. When the US switched from SAE gross horsepower to SAE net horsepower in 1972, the power output of all advertised cars was significantly reduced (e.g. the Chrysler 426 Hemi famously engine had  an output of 425 gross hp, but only 350 hp net).

 

The AVDS-1790 is however a robust design that had a lot of unused potential, as seen by the later variants (with up to 1,200 hp net horsepowers) used by Israel and others.

Thanks!
Engines really aren't my strongsuit so it's nice to see an explanation

1 hour ago, SH_MM said:

That is the third revision. The original M60A1 in SteelBeasts had 633 mm at the turret front and 400 mm on the mantlet, because the author assumed that the 254 mm was the physical armor thickness before slope...

http://www.tank-net.com/forums/index.php?showtopic=26578&hl=m60a1#entry618626

 

After that there was an intermediate version, still with way too much armor:

Yeah I remember that 
Always cracked me up when I saw those pictures...
 

1 hour ago, SH_MM said:

But the Leopard 1A3 is also overrated by Steel Beasts...

Yeah, I agree, I think 250mm is also quite high, though I guess it's possible in some areas.
 

1 hour ago, SH_MM said:

The Swedish protection analysis is focused on the crew compartment only; everthing outside the crew compartment is not analyzed. I know what you mean with the "slit" in the armor protection, but unfortunately I don't have an answer to that question. Maybe this is accurate and a result of how the armor elements are arranged within the array, but it also could be a minor error in the calculations.

This has been bothering me for some time now....

And the more I think about it, the more I'm convinced we'll never know until someone actually involved with the tests tells us.
 

My theory is that the values we have were tested but the colour scheme is more or less based on that but filled in the "blanks" with simulation of material thickness, think Warthunder like penetration mechanics with pixel projectiles.

What I'm not sure about is the graphs where we can see the different "versions" with the B tech version on the left with all the different angles and protection %s and the leo 2 "improved" on the right, are those "only" showing the crew compartment coverage or is that including all the visible armour?

2 hours ago, SH_MM said:

That might be related to the timeframe. The document is from 1969/1970, when the only 115 mm APFSDS NATO knew off had a steel penetrator with no tungsten carbide. It easily shattered when hitting spaced or sloped armor, while having overall rather low armor penetration (200-240 mm at 2,000 meters against flat steel armor).

Yeah it wasn't the best, still I think it's complacent or naive to think this "new" ammo type isn't much better or has better potential/ working mechanism than APDS.
I think it's probably still better than APDS against complex targets if they're not too spaced or with too thick layers.

2 hours ago, SH_MM said:

However the Soviets already had the 115 mm BM3 with tungsten-carbide slug at the tip of the steel penetrator, capable of penetrating 270 mm RHS at the same distance - this was AFAIK the first type of 115 mm ammunition accepted by the Soviet Union, but it was expensive and not exported, so NATO only knew about the all-steel penetrators.

Yeah, until 1981 where the Iranian chieftains got a kicking.... that was a pretty nasty surprise I think for the Brits.

6 hours ago, Wiedzmin said:

cast and rolled. it's not very high,before you ask high hardness not always means super brittle

 

 german panzer IV front plate(30mm) has 600 on outer surface(face hadened) and 418 rest part(core) of front plate, 50mm plate on G model was 500-520HB but these plates often was brittle  indeed

Interesting, didn't think they reached that high, I'm assuming that went down over the course of the war or?
 

1 hour ago, SH_MM said:

The weight of the gun trunion of a Stridsvagn 122 (Leopard 2A5) is 110 kilograms including the mounting supports.

Where did you get that?
I've been trying to find good info on it but... it's hard to get specifics, I also have to point out that the trunnion might've been changed going from 2A4 to 2A5.

If you look at 2A4 pictures from the inside, the trunnion is painted (probably against corrosion) while that doesn't seem to be the case on the 2A5s, if the pain was indeed against corrosion, that means the trunnion on the 2A5 could be made of a different material, not needing the paint to protect against corrosion, titanium would fit in this case.
 

The switch to a different material could be explained by the wedge of a mantlet adding quite a bit of extra mass (and therefore protection), lightening the trunnion could be a reaction to that, ofcourse, that's just speculation.

1 hour ago, SH_MM said:

The MB 838 CaM-500 has a weight of 1,950 kilograms. R. P. Hunnicutt lists the weight of the the M60's AVDS-1790 at  4,700 pounds dry (in case of the M60A1 and M60A2) and at 4,900 pounds dry (for the M60A3). That equals 2,132 kg and 2,222 kg respectively.

Odd, heavier engine that produced less HP and wasn't much more reliable if at all?
Was there another reason for it or just a less impressive part of the tank?

1 hour ago, SH_MM said:

According to "World War II Ballistics: Armor and Gunnery", the BR-412D can penetrate 235 mm of armor steel at 100 meters distance. Adding differences in criteria and steel hardness to this makes it rather possible that it could penetrate 240 mm armor steel at some ranges. But it seems US protection data is based on the BR-412B round with worse performance tested against cast armor only (at least the source is named "TACOM Ballistic Design Data 100 mm APHE BR-412B vs Cast Steel Armor"): so the hull armor protection might been under-estimated unless the US somehow thought that rolled steel plates with similarly low ballistic performance as the soft cast armor used for the turret was desirable.

I have reason to believe the numbers in WW2 ballistics are wrong, while I do realise I'm about to post a link to the WT forum of all places, I can guarantee you that Conraire and atleast two other people most definitely know what they are talking about as they have done a load of research.

Way more than I have and probably more than the vast majority of people interested in this topic.
 

That said, they're not flawless in their assessments and are still learning (aren't we all?).

So, 240mm I find highly dubious, maybe it would reach this against the cast armour of the M60s that had the lower hardness, I'm not entirely sure if the angle plays a role or if lower hardness is always xx% worse.

Still, I don't think this picture is entirely wrong:

Remarkebly, an SB picture that doesn't seem too far off, obviously, the turret ring isn't ever going to reach 254mm but the rest seems plausible.
 

1 hour ago, SH_MM said:

The claimed reduction betwen 5-15% reduction in protection is valid for 260-280 HB steel, not the 220-240 HB (which turned out to be only 210 HB during tests of a M47 Patton tank in Yugoslavia). Given that the US military used some of the softest cast armor and that even American authors like R. P. Hunnicutt criticized the poor quality of this steel, it seems likely that it would be closer to the 20% reduction in protection mentioned by German and Swedish sources.

Yeah, then in that case 20% does indeed seem more likely, I do wonder how exactly the tests were performed though, I've seen some sporadic mentions of cast armour deficits not being as noticeable at higher obliquities, is there any truth to that?
 

1 hour ago, SH_MM said:

Yes, the M60A1 should be able to survive being hit by a 100 mm AP at some places of the turret front, specifically at the better sloped parts - but not everywhere... and thats what matters.

True, but technically even a leopard 2A6 wouldn't survive a 100mm AP to the underside of the wedge if it bounces down into the hull, while I know that's a pretty weird thing to bring up, what I'm actually trying to ask is: do we know the criteria for what they considered a "penetrating hit"?
I've started to wonder a lot more about this after I've been reading the Swedish powerpoint on the trials, in their renders of the tanks you can see they only colour some areas and probably consider the others "inert", yet we don't get that info on their charts, same with the area around the mantlet for the 2A5 proto, there's small slits that seem vulnerable, was that intentionally "calculated" or just an artifact of the way they did their simulation?

Same goes for the leo 1A3 turret, though it does seem to have a slightly more "homogenous" armouring of the front.

I'm waiting for new measurements some people were going to do on the M60A1 turret, the angles don't seem that easy to get right just from drawings alone.

1 hour ago, SH_MM said:

The 50% metric somewhat makes sense, it seems to be the standard used by the US military based on numerous other documents. The BR-412B however is an odd choice.

Yeah, IIRC, army standards were the (in)famous 50%, while Navy seems a lot more like the Russian standards (75-80% or something).

Kinda curious as to how much the values would differ if they used different standards.
 

1 hour ago, SH_MM said:

Never said it was equivalent, but similar protection when seen directly from the front. The M60A1 has much better hull armor, better turret side and rear armor, arguably a thicker mantlet and it has a larger protected frontal arc.

Yes, I agree.
 

1 hour ago, SH_MM said:

But when seen directly from the front, the protection difference appears to be negible.

Yeah and honestly that's something that bothers me, it just doesn't make an awful lot of sense to me, maybe I looked at too many articles praising the armour protection of the M60s or downplaying the leo 1 armour but.....

1 hour ago, SH_MM said:

The Leopard 1A3's turret was apparently tested against 90 mm HVAP ammo with tungsten-carbide core (West-Germany never used simple APCBC for the 90 mm guns of Patton and KaJaPa), which in terms of raw penetration actually outmatches 100 mm AP(CBC/HE) rounds by quite a bit, but may or may not be more suspectible to damage by spaced armor.

 

In general spaced armor was very effective against older ammo, specifically against bullet-shaped rounds with spin-stabilization. The UK was happy, that the L15 APDS for the L11 tank gun of the Chieftain lost only 20% of its penetration against spaced armor arrays (after optimizations), while US tests showed that adding a 1/2 inch thick steel plate spaced in front of a 3-4 inches thick steel target could increase the protection against 90 mm M304 HVAP rounds dramatically (reducing the maximum range at which the armor can be penetrated by 1.500 to 2,200 yards depending on angle).

Yeah, I've noticed the different "priorities" or "accents" Germany, US and UK put on armour protection, what I found particularly curious is how the UK in the Burlington Chieftain research basically considered 115mm APFSDS equivalent or "probably" not much better than 105mm APDS.

With spaced armour there's always that random factor at play, or atleast that's what it looks like.

1 hour ago, SH_MM said:

Negative. First of all, the measure point is very close to the gun mantlet and gun mounting mechanism, which might be included at this very specific point. Cast turrets have variable thickness, so seeing one specific point having a certain thickness doesn't say anything.

I would agree, we need an entire array of pictures and overlayed onto a diagram to see where exactly it was taken, a single picture doesn't say that much.
 

2 hours ago, SH_MM said:

That puts LOS thickness at 261-290 mm and this value might be the result of the mounting mechanism for the gun being nearby. You keep forgetting that the 254 mm LOS thickness is the official figure used by the US Army in its internal documents. There is no logic behind prtending that the M60A1 has 300-350 mm KE protection at the turret (with ~400 mm mantlet), given that the US Army itself says that this is incorrect.

While that 254mm LOS figure seems to be the most common one for the cheeks , I've not seen any other official document state that 300mm or so is wrong, maybe the 254mm figure is an average across the frontal arc (30-45°?) or just a minimum when looked at from the front.

The mantlet does seem to have more though, I don't think 254mm is entirely correct for the entire turret, the mantlet seems closer to 300-350mm to me.

Anyway, from a purely frontal attack I guess the 1A3 really isn't that far off from an M60A1 turret in terms of raw protection, but it probably wouldn't stand up nearly as well against multiple hits or heavier shells would it?

Those thin plates seem like they would buckle quite easily even if they defeated the round.