Talk:Chobham armour

The common feature of 'Chobham' is NERA sandwiches - not ceramic laminates

It is well known to experts that the major compenent of 'Chobham' style armor is NERA panels. This is the reason why 'Chobham' has a high mass efficiency vs. HEAT projectiles. The article is misleading becuase it instead focuses entirely on speculation abour ceramic sandwiches, some of which is a result of a misinformation campaign.

There is a very good discussion here: https://below-the-turret-ring.blogspot.com/2016/03/chobham-armor-facts-and-fiction-1.html — Preceding unsigned comment added by 101.164.129.204 (talk) 11:42, 30 September 2020 (UTC)

The blog might have a point in that the term "Chobham" was initially applied to an early sandwich type project. The conclusion that later projects and production types did not use ceramic armour, is not justified by the documents discussed and is speculation on the side of the author :o).--MWAK (talk) 09:33, 1 October 2020 (UTC)

Do we have a source that demonstrates that Challenger I or II or the various Abrams variants contain ceramic elements ? As far as I can tell the best that can be done is catalogue various speculations. The extensive use of NERA is well established, as is the DU element in later Abrams variants.

Many books state this, as cited in the article.--MWAK (talk) 10:41, 2 October 2020 (UTC)

There are actual diagrams here of the early Abrams array- again it is largely NERA, in some areas there is a steel-'something'-steel sandwich. The 'something' may well be ceramic, or a glass, or even something else (steel of very high hardness, glass fibre reinforced resin etc.). https://below-the-turret-ring.blogspot.com/2017/01/early-m1-abrams-composite-armor.html

Interesting. Several points are note-worthy. The documents do not claim this is NERA. This is an interpretation of the blog-writer. The possibility is disregarded that several types of ceramic armour are applied in a single array. The bracket system emphasizes that such armours are modular. Different configurations might be chosen depending on the tactical situation. Such illustrations are also highly time-dependent, as through the years different types come available.--MWAK (talk) 11:01, 4 October 2020 (UTC)

It very clearly is NERA. Ceramic plates would not use that configuration, as the air gaps would reduce performance. Also it is not possible to gain entry to that cavity and place anything else in there. If there is ceramic in that array, it is likely the middle payer of the backing plate sandwich. 2001:8003:265E:2D00:8042:2B3F:1477:1A3F (talk) 13:01, 21 February 2023 (UTC)

I’ve been digging for information on this for ages, and I believe you are 100% correct. The armor shown in the unclassified documents are very clearly a type of spaced sandwich armor. The layout of these plates would be detrimental if ceramics were used, but are perfect for NERA. The fact that the armor is more effective against HEAT warheads than kinetic penetrators further reinforces this idea, as ceramics are decent at stopping both, but NERA is much better against HEAT warheads. Multiple sandwiched ceramic layers simply doesn’t make sense. The description of ceramic armor throwing fragments into the jet, and the irregular path made through the ceramic being responsible for degrading the HEAT warheads penetration is simply nonsense. The debris formed during penetration flows out around the jet or penetrator, it doesn’t fly into it because it’s being pushed out by other debris. The path punched through the armor is larger than the diameter of the jet or projectile, so the “Irregular shaped path” doesn’t matter at all. That’s assuming the path would even be all that different since the incredibly high speeds make the materials act much different than you’d expect. Simply put, there’s no way the armor is mostly ceramics based. The physics simply don’t work with the information we do have Deathdragon228 (talk) 00:27, 12 January 2021 (UTC)

Well, ceramic armour is very expensive and the British had a great many projects exploring the possibility of applying much cheaper spaced armour configurations. What was announced in the seventies as Chobham armour mainly pertained to ceramic amour, though.

Crack deflection is real and described in many scientific articles. Obviously some debris is thrown out. This very fact however, implies that the jet loses kinetic energy and medial pressure is applied to it. Of course these effects only become dominant in the end, when the jet is defeated. But that is the relevant phase :o).--MWAK (talk) 08:19, 12 January 2021 (UTC)

There is more useful information here, giving the models known to have ceramic elements:

'Leopard 2 since 1988, K2, Type 10, PT-91M produced for Malaysia. Also it is possible that some of the later Leclerc models incorporate ceramic layers in their armour arrays, given that some of the German research was carried out by the Franco-German ISL.

In addition to that tank armour arrays with ceramics were developed in Sweden, Switzerland and the United States, but apparently not fielded.

 *  In case of the Leopard 2, declassified documents from the UK (where the Leopard 2A4 was offered as part of the Chieftain replacement program) state that the West-German officials revealed the fact that the "bulging plate armor" of the earlier models had been replaced with ceramics on the 1987/88 model. Also a German company that produces ballistic ceramics cited the Leopard 2(A6) as a reference for the use of its products.

   * Regarding the K2 Black Panther, the company Samyang Composite Technology which manufactures the composite armor of the K2 MBT, the K21 IFV and various wheeled vehicles, claims that it developed a steel, aluminium and ceramic array for the K1A1, K2 and the Altay (the latter in cooperation with the Turkish industry)
   * As for the Type 10 tank, Col. Yasutaka Matsubara from the JGSDF included the following graphic in a presentation:

https://www.tanknet.org/index.php?/topic/47570-mbts-vs-peer-armament/page/2/#comment-1611857 — Preceding unsigned comment added by 2001:8003:265E:2D00:614A:E51D:1A44:8057 (talk) 05:18, 18 July 2022 (UTC)

Rampant speculation

This article is full of opinion and random hypotheses which aren't sourced. Wikipedia is not a place to speculate on things. Chris Cunningham 17:39, 25 August 2007 (UTC)

Ah, you are communicating. Good ;o). Now to business: the accusation of original research is a very serious one and should not be lightly made. Are you very sure you have the expertise to correctly identify any "opinion and random hypotheses"? Obviously the article needs inline references — putting them in is simply a very time-consuming process, the main reason they aren't there — but most of the content is very basic. Could it be that you have concluded, after reading popular accounts that the composition of Chobham Armour is "classified", that the entire principle of ceramic armour is some great undisclosed mystery? This is far from true, I assure you. I will start adding references — obviously I've been waiting for this — but there will remain a narrative gap between the very technical papers and the implicit knowledge they assume any reader to possess already.--MWAK 18:36, 25 August 2007 (UTC)

Well, yes. The lack on inline citations is exacerbated by the use of phrase like "it is probable that". It's also quite chatty; that "bit of a mystery" thing should be removed, because how a hairdryer works is a "bit of a mystery" as well. Chris Cunningham 08:57, 26 August 2007 (UTC)

In that case we will increase the level of formality — and of course the process of adding citations is far from complete :o). I'm not sure what you mean with "chatty" exactly. As far as I can see there are no sentences without informative content present and the account is quite bone-dry as it is; but perhaps you're an engineer or physicist and correctly perceive that a more quantitative approach would be able to perfectly describe in a single formula what a thousand words fail to express. Should you want to add a quantitative analysis, this would of course be most welcome; nevertheless it should be remembered that most readers would be unable to understand it and need a purely qualitative treatment also.--MWAK 13:34, 26 August 2007 (UTC)

Well, put it this way: what does the phrase "the exact nature of the protection offered is sometimes presented as a bit of a mystery" add to the article? It's obviously not from a source ("The BBC reports that Iranian weapons researchers have declared the level of protect offered by Chobham armour to be 'a bit of a mystery'"), and it is also obviously not going to be much of a mystery after one reads the rest of the paragraph (which somewhat demystifies it), so it would seem that the clause is both irrelevant and unwanted. Removing it increases the sourced:unsourced ratio in the article.

The second problem (which is really the key one) is that things are constantly phrased as "could be" rather than "is". How something could be composed isn't what we should be discussing. Take this: "To minimise the effects of this the tiles could be made as small as possible, but then the ratio between the area covered by tiles and that covered by the matrix would become more unfavourable, also because the matrix elements cannot be reduced accordingly as they have a minimal practical thickness of about an inch. An equilibrium is usually found at a diameter of about ten centimetres." Why the build-up? Just say that the tiles are produced at 10cm because this is the best compromise. This speculative, arrive-at-a-conclusion phrasing is okay for key points in the article, but it's used all over the place. It's possible that the whole "protective qualities" section could be merged into the construction one after this is corrected because of all the duplication it causes through being separate. Chris Cunningham 14:04, 26 August 2007 (UTC)

There are several issues at stake here. Firstly we are not capable of giving a detailed sourced description of the properties of the actual Ceramic Composite Systems used in the respective MBTs of the world's armies, simply because most of the relevant sources have not been made public as yet. What we can do however is to give a sourced presentation of the present state of the art of ceramic armour in general, while abstaining from the claim that this state of the art is really applied in any actual western tank. Therefore we can only describe such systems as "typical" — given the known state of the art of present ceramic armour technology as reflected by the technical literature — and possibly applied.

Secondly, you are mistaken to call "arrive-at-a-conclusion phrasing" speculative. Speculation is the suggestion of facts; what the text does is to give the known design principles and then logically infere from them the conclusions (of course within a certain assumed factual context). This is far from redundant as neither the principles nor their deductions will be obvious to the average reader. If the text merely stated that tiles are 10 cm wide, the reader wil not be given the insight why this must be so. Why not a continuous ceramic layer covering an entire turret side? This was in fact the original intention for the MBT-70. And when the reader is told why — to prevent extensive damage by a single hit — he still would need to be told why in that case tiles shouldn't be made as small as possible. Might be obvious to you and me — but not to most. Of course we could condense the phrasing: "The typical tile size of 10 cm is a compromise between limitation of impact damage and optimising the tile-matrix framework ratio given a minimal one inch framework bar width". This is shorter and we both immediately understand what is meant. However, this is because we already are acquainted with the subject. To the reader it would probably be a bit of a mystery ;o).--MWAK 16:58, 26 August 2007 (UTC)

While I appreciate that this is a fascinating subject, this sort of thing is why WP:SYN was developed. Composite armour has its own article, and as this is an article for a specific type of composite armour it should refrain from using sources which don't actually refer to said armour to advance an argument. On the tile size thing, I'm coming round to your suggestion that it just needs to be made more concise. Chris Cunningham 08:00, 27 August 2007 (UTC)

Well, though the lead section as yet imperfectly reflects this, "Chobham armour" has of course become a generic term for "ceramic vehicle armour" in general. Should we limit ourselves to its strictest meaning, not even the M1 or Challenger 2 can be said to be fitted with Chobham armour in the narrow sense. Composite armour is a much wider concept so merging the two articles seems undesirable. Should we create a new article "Ceramic vehicle armour" we would be forced to begin this with "Ceramic vehicle armour, commonly known as Chobham armour..." — but if "Chobham armour" is the common name, it should in principle be the article title.

As the concept is general, I tried to give a general treatment of ceramic armour technology. I fail to understand what special argument I could be advancing by this. Obviously this would be different if Chobham armour were such a complete mystery that it would not even be certain that it was ceramic armour — for then the emphasis on this armour type would be biased. However, again the lead section is as yet incorrect: we have good official, public and published information on the basic properties of Chobham armour in the narrow sense.--MWAK 18:29, 27 August 2007 (UTC)

The intro edits are good. I'm going to de-tag this and see what else I can do to help out. Thanks for working so diligently on this. Chris Cunningham 08:44, 28 August 2007 (UTC)

This whole article is a big ball of hot air you have no idea of the armour as it’s a government secret as well as not even knowing who utilised it first and what country you can write as many papers on it as you want Doesn't mean you no what your on about — Preceding unsigned comment added by 2A00:23C6:66CB:3201:9B2:141C:709E:451C (talk) 23:24, 30 November 2019 (UTC)

Well, the fact that the Americans used it first — your main objection, I believe, is generally known and well sourced. Of course, it depends on definition. "Chobham" is here used as a more generic designation. As the article makes clear, the Americans applied armour of a different composition and structure than the ceramics fitted on the Challenger 1. --MWAK (talk) 07:47, 1 December 2019 (UTC)

Arguable and non-verified content

I've read the article several times, but there is much information without citation/verification.

• The whole article is giving no real hint of the composition of Chobham armour, it is only talking about generall ceramic matrices armour ("Chobham-style armour"). Therefore the article includes a list of ceramics (boron carbide, silicon carbide, aluminium oxide (sapphire or "alumina"), aluminium nitride, titanium boride), but no really quotations which ceramics are used.
• The article claims that the MBT-70 was protected by silicon carbide. No citation is given. The armour of the MBT-70 is according to serveral other sources, the English Wikipedia article and the German equivalent described as spaced armour (Schottpanzerung (1st generation) in German).
• The development section includes serveral sentences/phrases which aren't part of the development of Chobham armour and therefore aren't relevant.
• The usage of Chobham armour in the Leopard 2 is generally denialed in this article. In fact most sources claim that the Leopard 2 uses a special kind of composite armour including Chobham-style ceramic matrices. Encyclopedia Britannica and the German Wikipedia article (based on books written by W. Spielberger, Frank Lobitz, etc.) claim that the Leopard 2 uses a Chobham-style armour. Christopher F. Foss claims in the book "Panzer und andere Kampffahrzeuge von 1916 bis heute" (Illustrated encyclopedia of the world's tanks and other fighting vehicles) from 1977 that [...] at the end of 1976 it came out that the in Great Britain developed Chobham armour was used. The early prototypes [1] [2] used the same type of armour as the Leopard 1A3/1A4, but some prototypes [3], the Leopard 2AV and the production models all have the slab-sided appearance, which is according to the article typical for Chobham/Chobham-style armour (Instead of rounded forms, the turrets of tanks using Chobham armour typically have a slab-sided appearance).
• The M1 Abrams is according to this article using Chobham armour, although it is told to be a modificated version which includes a DU layer.
• Ceramic polystyrene foam is mentioned in the text. Polystyrene is not a ceramic foam, it is a kind of plastic. Foamed polystyrene (sometimes known as Styrofoam or Styropor) doesn't have the same potency as a layer of unfoamed polystyrene
• The article includes several (obvious) false claims about the usage of perforated armour. The Leopard 2 would use a armour system mainly relying on perforated steel plates. How can the Leopard 2 with such a type of armour be having a higher protection level agianst chemical energy than against kinetic energy? Why do other sources (mentioned above) claim the opposite? And why should "Armored Cav — a guided Tour of an Armored Cavalry Regiment", a book about the American tanks, be considered a reliable when it comes to German tanks? Not to forget that the first series produced Leopard 2 already had the slab-sided turret [4].
• Furthermore the article mentions "[...] the very large procurement, maintenance and replacement costs of those ceramic armour systems not based on the cheap but rather ineffective alumina.". I've never heard about anything like that. How to replace the ceramic tiles? They must cut through the outer layers of the armour and the matrix. What kind of maintenance has to be done? They also would have to cut through the outer laysers of the armour/matrix to reach the ceramic tiles.
• Imo this article should be renamed "Chobham-style armour" or the content should be reduced to the early M1 and Challenger 1/2.
• The useage of ceramics in aircrafts is not worthy to mention in an article about a type of tank armour.
• I've heard that Chobham, which itself is not an official name, is also called Burlington (or somehow affiliated with it). Declassified documents shows that this armour was presented to the FRG.

--Tim.vogt (talk) originally posted 11:37, 28 November 2010 (UTC), reposted by --Tim.vogt (talk) 11:15, 4 January 2011 (UTC)

Concerning the LEOII and perforated armour. Maybe the confusion is because modern armour doesn't consist of a single type of armour, but instead consists of multiple types of armour, each type designed to give a certain "effect". One could suggest that an armour system had perforated armour on the outerside (primarely to defeat Ke rods, and offer some defense against HEAT) backed by composite or chobham armour on the inner side to primarely defeat HEAT and stopping weakened (by the outer armour) Ke penetrators.

So it would be a "both". Jomsviking (talk) 12:03, 3 January 2011 (UTC)

User Tim.vogt had withdrawn his contribution. Though it raised a lot of valid points and pointed out many possible misconceptions, I feel it is best to respect his decision, so I will again remove it for the time being. Maybe your reaction will motivate him to reinsert it or an improved version. Certainly you are correct in suggesting that modern armour packages might use a combination of armour types. It would be more typical to have the ceramic armour on the outside, though, just as with the later M1 systems.--MWAK (talk) 20:47, 3 January 2011 (UTC)

I didn't withdraw anything. I added the section twice (due to some connection troubles) and removed the second one, you later removed the other, which was intented to remain. Btw. the outmost armour layer shouldn't consists of a Chobham like matrix structure, else it would be damaged (not penetrated, but it would lose stability), when hit (even by smaller 30 and 40 mm APFSDS). At least the Challenger 2 has two steel (?) layers bolted on the turret front. --Tim.vogt (talk) 11:15, 4 January 2011 (UTC)

My apologies. I hadn't noticed this or I would have answered sooner. Whether they should or should not :o), on the M1 the outer layers consist of ceramic armour modules. Indeed this makes these susceptible to damage by rapid-fire cannon.--MWAK (talk) 13:34, 4 January 2011 (UTC)

Jomsviking, I personally believe it is a mere missinterpretation. Mostly "perforated armour" is explained as "layers of steel at different angles". In German the term Schottpanzerung or Mehrschichtschottpanzerung is sometimes used to describe the armour of the Leopard 2. This term doesn't have an adequate English counterpart, but imho "laminated armour" or "(mulit)layered armour" would be matching. Schottpanzerung can itself be subdivided into three generations: the first generation (used in MBT-70 and Marder 1A3) consists of spaced steel plates, while the second (used in the Leopard 1A3/A4 and early Leopard 2 prototypes (PT 1 - 17?)) can already seen as "real" composite armour. Although I personally don't really believe that perforated armour is incorporated in this tank, the current article doesn't point out that the Leopard 2 doesn't only rely on it, but also uses other composite armour. The German sources I've read doesn't mention any perforated elements, but instead high hardened steel, ceramics, plastics and rubber. --Tim.vogt (talk) 11:15, 4 January 2011 (UTC)

Tim, sounds reasonable. Regarding the perforated armour on LeoII, I was told by a (danish) tanker that the (some of) armour on the LEOIIa5DK was "a kind of steel with cavities filled with some kind of foam" I translated that into some type of "perforated armour". Now eventhough many internet sites put extreame credibility into the testemony of soldiers/tank crew, I think they lack the material physic knowledge to have a clue about what they are seeing, but that's just an oppinion (not that I am an expert on the subject, though I know enough to know that I don't really don't know anything about it) — Preceding unsigned comment added by Jomsviking (talk • contribs) 11:58, 4 January 2011 (UTC)

Some time ago the Leopard 2A5s of Danemark were upgraded with MEXAS-H applique armour on the hull, i.e. ceramic tiles and a outer steel were bolted on. Maybe he was talking about this? Another explanation might be the usage of tungsten. Tungsten can't be used effectively without a harder bonding structure. According to the German wikipedia tungsten is normally inserted into small holes inside a nickel or steel plate, which later is hardned. The DU-layer in the M1s armour is also using a special structure ("steel encased DU wire mesh").

But how does he get information about the Leopard 2 armour? No tank was licence built in Danemark. And afaik the repairs on the tank armour are done by KMW. --Tim.vogt (talk) 12:36, 4 January 2011 (UTC)

"But how does he get information about the Leopard 2 armour? No tank was licence built in Danemark. And afaik the repairs on the tank armour are done by KMW"

Don't know Jomsviking (talk) 20:26, 4 January 2011 (UTC).

The Danish tanker was basically right :o). Probably someone took the trouble of correctly informing him. Always good for morale, I'd say. Schottpanzerung, though its literal meaning is different, is in the literature used as a synonym of "spaced armour". Even the hardest (armour) steel or nickel is considerably softer than any tungsten alloy used.--MWAK (talk) 13:34, 4 January 2011 (UTC)

That depends on the source and the date. In the 70s and 80s (there were some nice article/books about tanks) the term was used more often for composite armour, nowadays it is more affiliated with spaced armour. --Tim.vogt (talk) 13:51, 4 January 2011 (UTC)

"Schottpanzerung", Doesn't "Schott" mean something like "Bulk head" ("Skot" in danish)? IF true, Maybe that gives an idea of the "Schottpanzerung" as an armour structure resembling that of the compartemensation of a ship? Maybe a distinction to spaced armour, is merritted by the structure not only given more depth to the armour at constant weight (which is basically the spaced armour idea) but, I imagine, that multiple "bulk heads" (plates of armour) made with different hardnesses can play a role in deflecting or tipping a penetrator within the armour "package"??? (or is that far out?) Jomsviking (talk) 20:26, 4 January 2011 (UTC)

That's correct, "Schott" can be translated as bulkead. Schottpanzerung could be determined as "armour with an outer and an inner layer consisting of metal". The Leopard 2 armour is built "inside" the tank walls [5]. As I allready mentioned there are claims of several materials/structures being used inside the armour. I.e. layers of steel (high-hardened), tungsten, the English wikipedia claims titanum would be used, ceramic, plastics and rubber. Imho it is probable that the outermost layers of the armour consits of steel (and rubber or plastic), followed by a ceramic matrix (Chobham-style) which is backed by a tungsten layer, followed by another plastic/rubber/steel composition. --Tim.vogt (talk) 20:49, 4 January 2011 (UTC)

Ohh, my wast knowledge of german! ;) Anyway, concerning the tungsten, which I quess is used for defeating Ke penetrators. Why do they place it at the back, I would suspect that you wanted it at the front?Jomsviking (talk) 22:45, 4 January 2011 (UTC)

As far as I know Tungsten (or DU) itself is not a very good armour material on it's own, since it has a hardness of only some 294 HB (lying in US armor class 1 & 3 for a 1.25 inch thick steel plate [at least in the 90s]). But Tungsten or DU have a very high density, therefore it is used as backing plate in the ceramic matrix, which increases the ceramic tiles efficiency against kinetic energy. I believe that the ceramic matrix is located behind a sequence of (hardened) steel, rubber and/or plastic layers, which should offer at least protection against medium caliber rounds (and maybe even more). But that's just opinion. --Tim.vogt (talk) 10:53, 5 January 2011 (UTC)

Well, pure uranium is rather soft. Therefore it is used in alloys with titanium or nickel, which alloys are as hard as armour steel. Pure tungsten though is extremely hard in itself (2570 HB) and is used in alloys to make it tougher. Tungsten nor uranium are typically used as backing plates; they are difficult to apply in plate form ("heavy armour" has the form of perpendicular rods) and density is not all that relevant for a backing plate. Their alloys would be so hard that they would reflect too much energy and thus increase damage to the tile in case of an impact. It's true that the ceramic armour could in principle be protected by a thick outer layer of steel but modern 30-40 mm rapid fire cannon are so powerful that you would need about 120-150 mm steel to effect this. As the weight of a 55 ton tank turret armour is equivalent to about only 400 mm RHA frontal protection in the first place, you can't afford to apply a third of that weight in the form of conventional steel as it would comprise the entire special armour concept (which was why the Challenger 1 which still used a cast steel inner turret was replaced by the Challenger 2). That mass can be used about three times as effective in the form of perforated armour. The outside of the modern Western tank turret is basically just a thin-walled container. Nor is the outer wall backed by plastics or rubber; while it is true that this could dampen the impact to protect a ceramic tile attached to it, this is irrelevant because there simply are no such tiles: the armour is modular. In the container removable metal boxes are placed with the matrix plates inside. These boxes do not touch the outer wall.--MWAK (talk) 09:03, 6 January 2011 (UTC)

2570 HB? You must be kidding, this value can't be true. You can take a look at matweb where the hardness of pure Tungsten (249 HB, as hard as a medicore steel) and some commercial alloys can be seen. No alloy of the one I checked had a hardness even close to 1000 HB. Hard materials tend to break or shatter (like ceramics), a property which makes them useless as penetrators (Tungsten and DU are used as penetrators for APFSDS/APDS, while the Soviets did/do use some steel parts). And afair density is a important factor for the usefullness as backing plate (I've read this in imo reliable sources and it makes sense in the physical aspects). If you don't believe it is usefull as backing plate, why/and where would you use it? Ceramics itself are pretty hard and can be used for protection against KE (as proven by MEXAS and AMAP). Why would you use such a high-densitity (heavyweight) material if you can use low-weight ceramics instead? Armour thickness doesn't seem to be an important reason.

Regarding the steel (rubber/plastic) composite armour at the front: the Challenger 2 has two rolled steel plates (imo ca. 50 mm) bolted on the turret front. They are pretty easy to see: [6]; Here is a Challenger 2 without bolted on parts (in front of the Bovington tank museum). From the thickness they might be not as thick as required to fully adsorb the impact energy of modern medium caliber APFSDS, but they are told to be high-hardened (they would cause spall, but this would only hit the base armour), they work as disrupting stage. Regarding the ~ (350 -) 400 mm RHAe frontal, you seem to speak of the M1 Abrams (basic model), which didn't have largely superior KE protection than other contemporary tanks (Leopard 1A4 turret ~ 300 mm, T-72 ~ 305–410 mm, T-64 ~335 - 450 mm) and therefore might not be the best example. But: the Chieftain had 380 mm thick frontal steel armour and a weight of some 55 tonnes.

Do you believe that the M1A1 (or the Leopard 2A4) have some 80 cm thick "Chobham armour"-boxes on the turret front or do you support my opinion that other laminated armour is also used? And how to "replace" them (in the case of the Leopard 2 and the M1A1/2 these "boxes" are welded together to the turret/or a "roof" plate was welded upon them)? --Tim.vogt (talk) 14:24, 6 January 2011 (UTC)

Point taken: 2570 is of course its Brinell MPa number, not the HB value. Well, it is still one of the hardest natural elements ;o). Certainly when properly treated. As regards the use of hard materials as penetrators, one should not confuse hardness with brittleness. Tungsten carbide is very hard but was still widely used in AP-rounds, though admittedly shattering was a problem.

When the Americans began to add uranium modules, they openly stated the reason for it: ceramics are less effective against KE-penetrators. I.e. less effective per unit of weight. The main reason for this was that the uranium was given the form of what has been described as a "mesh" or as "rods". So it is a perforated armour system, combining solid parts with cavities. The penetrator must therefore either hit a solid part, being of extreme thickness because the weight saved by the cavities can be concentrated there or travel through several cavities subjected to the edge effect, sloped armour, differential hardness, toughness and density, all this causing abrasion, deformation or breakage. Using heavy metal components instead of only steel or titanium offers the advantages of limiting the armour thickness to better fit a pre-existing tank design (so, the thickness is relevant) and increasing the material differentials. And in general, metal systems are of course a lot cheaper than ceramic tiles. So, unless one is locked in some design path dependency as happened to the poor Yankees, these are better avoided.

As regards the case of the Challenger 2, you made the very plausible suggestion the frontal turret plates might be disruptor elements. However, such might be useful whether there is a ceramic armour present or not and would also function against large calibre penetrators.

When referring to a 400 mm steel equivalence I meant the weight, not the protection level. So a 55 ton tank will have the mass equivalence of 400 mm steel to put on the front of its turret, whatever the system he uses. Dependent on that system the protection levels might vary wildly — precisely the reason to use as least conventional steel as possible.

In the case of the M1 it has been disclosed that the armour package is divided in a ceramic tile system in the front and a uranium mesh system more to the back. Given the advantages made in ceramic armour protection against HEAT-threats, the tile matrices are today likely rather thin. To the best of my knowledge, there has been no official source stating that any Leopard 2 model is equipped with ceramic tiles. It's very confusing trying to interpret all this as a "laminated armour". Real laminated armour-ceramic sandwiches were developed in the sixties but proved to be a failure, the very reason Chobham was such a breakthrough. Certainly the heavy metal really doesn't resemble a laminate; it is not applied in "layers" or "plates" but as largely perpendicular components. To weld the boxes (there is a nice picture of them in Char Leclerc: De la guerre froide aux conflits de demain) to the container walls or roof would be impractical; they are secured by means of bolts, clamps etc. To replace them one has merely to weld open the turret roof weld seams, which can be done in the field if necessary.--MWAK (talk) 18:46, 6 January 2011 (UTC)

* You say depleted Uranium (DU) is "rather soft" and it would be in special alloys which contain Titanium or Nickel as hard as armour steel. Then why would they use DU (even as perforated elements this would be any senseless, if DU would be only as hard as steel while having a much greater weight)? And your statement that the DU is used ater the ceramic matrix imho supports my opinion: DU and Tungsten aren't very effective on their own. If the DU "mesh" is located behind the ceramics, it might work as "backing plate".

* There are several sources claiming that the Leopard 2 uses a Chobham-like armour: the oldest one I found is from 1977. In this Christopher F. Foss (& co-authors) says that at first it was believed that the Leopard 2 used Schottpanzerung (as the first prototypes did), but then "at the end of 1976" it came out (or it was announced, this is troublesome to translate without being biased) that the in Britain developed Chobham armour/system would be used. Furthermore he gives one pretty simple description of Chobham: "This [Chobham armour] is several layers of steel and ceramic plates [tiles], which alternate each other." Then there is the scan/images of original British documents, which shows that the British already demonstrated "Chobham" (i.e. Burlington) armour to a West German comitee as early as 1970. Worth mentioning is also the fact that there was a Anglo-German joint project, the FMBT programme from 1972 to 1977. The article currently contains a sentence, which supports the useage of Chobham/Chobham-like armour in the Leo 2: Instead of rounded forms, the turrets of tanks using Chobham armour typically have a slab-sided appearance. The German wikipedia, itself citing several books, also claims that a Chobham-like armour is used.

* The Leclerc MBT is having modular (exchangeable) armour, the Challenger 1 & 2, the M1 Abrams and the Leopard 2 don't have modular base armour. Their armour is "built-in", changing the turret armour composition would require a new turret. [7] [8]

--Tim.vogt (talk) 14:49, 8 January 2011 (UTC)

The protection offered by a metal armour component is not only determined by its hardness but also, among other aspects, by its density or mass. Disregarding other advantages, a uranium perforated armour mesh a foot thick would thus provide the same protection as about 80 cm of steel. No weight gain compared to a steel perforated armour per definition — but a lot of space saved. So using this option would obviate the need for very major design changes when improving the protection level against KE-threats. Possible other advantages of heavy metals include increasing the density differentials which improves the chance of the penetrator being deformed or breaking. The backing of a ceramic tile matrix is a very specialised component, optimised to support and cushion the tile in such a way that the damage to the matrix by an impact is minimised. Making the ceramic directly touch the mesh would be far from ideal, to put it mildly. Of course you could put a plastic layer in between but that would still compromise the modularity. In this modularity there is no fundamental difference between the Leclerc and the M1 and Leopard 2. What was different was that the French chose to openly present it as an advantage. And the outer stowage box rim of the Leclerc turret was originally meant to hold an ERA-layer. The pictures you referred to are very illuminating: they show the basic turret as it is: a thin-walled empty container in which the modules can be placed (the Challenger 1, in essence still using the cast Chieftain turret, is a major exception in this respect). Obviously the factory revision is an ideal opportunity to check, maintain or replace the modules. But it can be done in the field also: the Americans in 1991 openly stated that the new uranium mesh modules were inserted by the troops deployed at the Iraqi border in Saudi-Arabia. One should not be deceived by simplistic diagrams of "special armour": they suggest it is a single block with all components tightly jammed in. This would however be hugely impractical and be a major obstacle to easy production, maintenance and replacement. The Soviet system was basically different from Western practice of course.

The 1976 incident is a delicate matter. We have to understand it was not a deliberate deception. The Chobham facilities brought forth two major developments: the one was the tile system, the other the use of foam. The Germans adopted the foam, using it in an improved form with a ceramic powder component in combination with armour laminates for the Leopard 1 A3 and A4. Later, when the demanded protection levels against KE-threats increased, this was further developed into a perforated steel armour system. When the Americans made the choice for a ceramic tile system, they began to exert considerable pressure on the Germans to adopt it. Late 1976 the Germans, against their better judgement, still cherished the hope that the Leopard 2 might be chosen as the common American-German tank, so they kept open the option of using ceramic tiles. At the same time they had begun changing their perforated steel system by replacing the foam in the cavities by alumina inserts, a version later rejected because the weight and cost penalty was not justified by the very marginal increase in protection against HEAT-threats. In 1976 the British and Americans disclosed the existence of "Chobham". This put the Germans in a awkward position: as they had earlier stated that their models were protected by spaced armour, this would now give the false impression that the Leopard 2 would be a generation behind and grossly inferior to the M1. Given the fact that at the time there was a real possibility it might indeed be equipped with it, they thus claimed that the Leopard 2 would be protected with Chobham-equivalent armour. This of course had the advantage of them not having to disclose their own perforated armour concept! Eventually the Leopard 2 would not use "Chobham". BTW, though a slab-sided turret is logical for a tank using ceramic tiles, the reverse isn't true: slab sides do not imply Chobham but modularity. The Leclerc is slab-sided too, though this is obscured by the bevelled stowage boxes.--MWAK (talk) 09:22, 9 January 2011 (UTC)

The whole article is incorrect Chobham armour was developed by the uk and used first by the uk and it isn’t just the uk and USA that utilise this armour also it has never been penetrated not one single challenger two main battle tank was destroyed in the whole of the Iraq campaign a good source of information would be to look up bovington tank museum the home of British armoured vehicles from WW1 all the way to current theatres — Preceding unsigned comment added by 2A00:23C6:66CB:3201:9B2:141C:709E:451C (talk) 23:19, 30 November 2019 (UTC)

Well, as the article clearly states, it was indeed developed by the UK. But it was the USA that first applied it in production vehicles. The Bovington site, though quite useful as a first introduction to general tank history, is simply not a reliable source on this technical subject. You must adjust yourself to the fact that popular accounts are typically extremely simplified and riddled with error. Luckily, there's Wikipedia ;o).--MWAK (talk) 08:05, 1 December 2019 (UTC)

precise and formal

In what way is this wrong?- Chobham armour is the composite armour developed in the 1960s ...

All wikipedia needs is that "Chobham armour" is the wp:commonname. To say- is the name informally given to, is wrong unless there is another common name. If there is another name we should use that instead. Bhny (talk) 12:22, 7 May 2013 (UTC)

The "informally" simply informs the reader that it is not an official type designation. It is important to stress this to avoid ambiguity. It is not a matter of stating the obvious as the "common name" might well have coincided with the official one. Also there is the problem that the name might be used in a limited sense, only referring to the British project, or in a more general sense for any type of ceramic armour. This makes it even more desirable to be clear from the onset about its informal nature. Past experience has taught me that all kinds of confusion will result otherwise :o).--MWAK (talk) 06:02, 8 May 2013 (UTC)

what is the official name? Bhny (talk) 13:25, 8 May 2013 (UTC)

Good question :o). The generic concept of course does not have a single official counterpart. The British armour seems to have been known as "Burlington" but even that is not a formal factory designation.--MWAK (talk) 18:39, 8 May 2013 (UTC)

Although only a guess, I suspect that at some time it may have had one of these; List of Rainbow Codes — Preceding unsigned comment added by 80.7.147.13 (talk) 19:23, 24 January 2014 (UTC)

https://en.wikipedia.org/wiki/Heavy_water

I have watched some military television content and I noticed that a greater explosive reactive force could be achieved when water seperated the explosive detonation and the target.

I notice there is something called Heavy Water on wikipedia

Would an inclusion of heavy water in your reactive armour provide a greater counteracting force?

I think all this knowledge is in the dambusters project.

Best Regards

Darren Mark Horton

82.29.73.4 (talk) 15:51, 2 April 2017 (UTC)

Well, it depends against what kind of explosion you want to protect. Normally, any protective belt defending against a single explosion is ideally very tough and at the same time very inelastic. Like some ceramics really. Water in general is not ideal. Heavy water is somewhat better but unless you are designing an interplanetary spacecraft and need water as a belt to protect against cosmic radiation anyway, I wouldn't bother. And you can't use heavy water as a normal consumption supply because in the end it wrecks your cell chemistry. You'll get sterile and ultimately you die.

For protection against hollow charge explosions, water is pretty good but not good enough to be practical for use on vehicles.

But perhaps this is not what you are really asking. If e.g. a depth charge would explode in a heavy water ocean, would this lead to greater or lesser damage to a submarine? I'm not quite sure but I presume the expansion and contraction cycle would be intensified, leading to greater damage.--MWAK (talk) 16:59, 2 April 2017 (UTC)

External links modified

Hello fellow Wikipedians,

I have just modified one external link on Chobham armour. Please take a moment to review my edit. If you have any questions, or need the bot to ignore the links, or the page altogether, please visit this simple FaQ for additional information. I made the following changes:

• Added archive https://web.archive.org/web/20111208004703/http://www.tanknutdave.com/component/content/article/305 to http://tanknutdave.com/component/content/article/305

When you have finished reviewing my changes, you may follow the instructions on the template below to fix any issues with the URLs.

This message was posted before February 2018. After February 2018, "External links modified" talk page sections are no longer generated or monitored by InternetArchiveBot. No special action is required regarding these talk page notices, other than regular verification using the archive tool instructions below. Editors have permission to delete these "External links modified" talk page sections if they want to de-clutter talk pages, but see the RfC before doing mass systematic removals. This message is updated dynamically through the template {{source check}} (last update: 18 January 2022).

• If you have discovered URLs which were erroneously considered dead by the bot, you can report them with this tool.
• If you found an error with any archives or the URLs themselves, you can fix them with this tool.

Cheers.—InternetArchiveBot (Report bug) 01:50, 9 December 2017 (UTC)