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On 6.4.2018 at 8:03 PM, Olds said:

It's a very nice summary, so I'd love to see the sources I'm missing that provide the additional specificity. My search terms may have failed me and I may have missed the links b/c I'm new to the site...

 

What are you exactly looking for? The T-72 protection requirements are taken from Zaloga and a Russian website.

 

20 hours ago, Laviduce said:

here is some info dealing with the protection requirement of the Chieftain of the 1980s:

 

Chieftain_protection_medium

 

 

This also makes me believe that the turret "cheek" armor protection of the Challenger 1 is 500+ mm RHAe against subcalibre KE threats. The Armed Forces Journal estimate of 580 mm RHAe and the British CR1 engineer "rumor" of 620 mm RHAe seem indeed plausible.

 

Well, this is very interesting and also would explain why the British FVRDE assumed that the Chieftain with add-on armor was better protected than the Leopard 2 at the turret front.

However there seem to be some questionable statements:

  • the author states that the the "bulge" created by the mantletless turret design has a thickness of 500 mm. This seems to be only the case when directly hitting the edges; it has been stated by other sources that the thickness is only about 300 mm.
  • the author ignores the differences in armor protection provided by cast steel and rolled armor steel.  According to British sources, the hardness of the cast steel was only 260 to 280 BHN, which is the same as Soviet cast steel. The Soviets found that ~260-280 BHN cast steel offered between 5 to 15% less protection than rolled steel with a hardness of 350 BHN (as used for the hulls of T-54, T-55, T-62 and later tanks).
  • the glacis plate is not effectively 388 mm thick; maybe it is a type and was meant to be 288 mm, which be roughly maximum protection level of the hull front; however it seems more likley that the author just copied the false value from Wikipedia. Measurements on the real tank with an ultra-sonic probe have shown a hull armor thickness ranging from 80 to 89 mm, which would be 259 to 288 mm along the line of sight. The British requirement as found in declassified documents asked for 120 mm at 60° (240 mm LOS); ~84 mm at 72° was believed to provide equivalent protection.

As for the Challenger 1's armor: 500 mm steel-equivalent protection might be possible, given the date of introduction and its huge weight, but it certainly is not set in stone. Confirmed is that the Shir (Iran) 2, which was used to develop the Challenger 1 tank, had a protection level of 325 mm along the 30° frontal arc (?) in 1978. Given the power-to-weight ratio listed in the British documents, the Shir (Iran) 2 tank weighed 63 to 64 metric tons, just as much as the Challenger 1. In so far the British engineers would have needed to completely redesign the armor array to reach the desired level of protection. In 1978, a protection level of 435 mm vs KE (as achieved on the MBT-80) was considered to be "enough". Originally the Shir (Iran) 2 was to be delivered in 1979 and 1980; but the deal was canceled with the Iranian revolution of 1979. The decision to not continue the development of the MBT-80 was made in July of 1980, the first Challenger 1 pre-series vehicles were delivered in 1982; so if the armor was massively redesign, it must have been done in a rather short period of time... so it remains questionable how much changes were made.

 

As for the "engineer rumor": Given the source of this rumor, I would completely discard it until another source supports it.

 

10 hours ago, Laviduce said:

I also read that the CR2 was expected to have a KE resistance lower than that of the M1A1 HA. I think this came from a British assessment document.   Yet there is a problem , the British were aware of the threats posed by the 125 mm guns. There is little reason to believe that the British were not successful of reaching a protection level of 500 mm RHAe in the 60 frontal arc. This would translate to about 580 mm RHAe from the front. The M1A1 HA KE protection in the frontal 60 degree arc was stated to be around 600 mm RHAe. This would translate to a KE resistance of up to 690 mm directly from the front.

 

Based on drawings of the Challenger 1 tank, the frontal turret armor modules are sloped at 26-28°, but the turret front of the M1A1 HA is sloped at 28° (in front of the gunner's sight) and 36° (in front of the loader's place) - that means that the gain in protection when attacking at 0° instead of 30° from the turret centerline is different (i.e. the left turret front module of the M1A1 HA would gain less additional protection compared to the right turret front module), which complicates the matter. Also note that modern armor arrays thanks to including NERA sandwiches as well as potentially certain materials like glass and ceramics do not provide the same amount of efficiency at all angles. The armor could be designed to provide maximum efficiency when being hit at 30°, thus the protection could be a lot more homogenous along the frontal arc.

 

7 hours ago, Collimatrix said:

I note that in 10 pages, the Abrams, Leo 2 and even Challenger have had their defenders, but nobody has gone to bat for the Ariete.

 

Well, there are reasons for this...

 

 

31052007965.jpg

 

Turret side armor of the Ariete seems to be comparable to the Leopard 1A3...

 

1346553201m_SPLASH.jpg

 

100-120 mm side armor probably is not enough to resist ATGMs, AP(FS)DS rounds and RPGs even when hit at very narrow angles. Luckily the Italian military is clever enough to buy add-on armor packages before deployment to Iraq.

7300a5011263decc94bf0b982103fb22.jpg

 

It is honestly a very odd tank. While the turret side armor seems to be way below average, the hull side armor at the engine compartment seems to have an above average thickness.

CjRDH0Y.jpg

 

 

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1 hour ago, Mighty_Zuk said:

Dude what the fuck

Apologies ! I  was just really looking forward to finding some original sources on the protection level of the Ariete, yet  it turned out that i was moving in circles yet again.  What a shame !

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1 hour ago, SH_MM said:

 

-snip-

 

 

Well, this is very interesting and also would explain why the British FVRDE assumed that the Chieftain with add-on armor was better protected than the Leopard 2 at the turret front.

However there seem to be some questionable statements:

  • the author states that the the "bulge" created by the mantletless turret design has a thickness of 500 mm. This seems to be only the case when directly hitting the edges; it has been stated by other sources that the thickness is only about 300 mm.
  • the author ignores the differences in armor protection provided by cast steel and rolled armor steel.  According to British sources, the hardness of the cast steel was only 260 to 280 BHN, which is the same as Soviet cast steel. The Soviets found that ~260-280 BHN cast steel offered between 5 to 15% less protection than rolled steel with a hardness of 350 BHN (as used for the hulls of T-54, T-55, T-62 and later tanks).
  • the glacis plate is not effectively 388 mm thick; maybe it is a type and was meant to be 288 mm, which be roughly maximum protection level of the hull front; however it seems more likley that the author just copied the false value from Wikipedia. Measurements on the real tank with an ultra-sonic probe have shown a hull armor thickness ranging from 80 to 89 mm, which would be 259 to 288 mm along the line of sight. The British requirement as found in declassified documents asked for 120 mm at 60° (240 mm LOS); ~84 mm at 72° was believed to provide equivalent protection.

As for the Challenger 1's armor: 500 mm steel-equivalent protection might be possible, given the date of introduction and its huge weight, but it certainly is not set in stone. Confirmed is that the Shir (Iran) 2, which was used to develop the Challenger 1 tank, had a protection level of 325 mm along the 30° frontal arc (?) in 1978. Given the power-to-weight ratio listed in the British documents, the Shir (Iran) 2 tank weighed 63 to 64 metric tons, just as much as the Challenger 1. In so far the British engineers would have needed to completely redesign the armor array to reach the desired level of protection. In 1978, a protection level of 435 mm vs KE (as achieved on the MBT-80) was considered to be "enough". Originally the Shir (Iran) 2 was to be delivered in 1979 and 1980; but the deal was canceled with the Iranian revolution of 1979. The decision to not continue the development of the MBT-80 was made in July of 1980, the first Challenger 1 pre-series vehicles were delivered in 1982; so if the armor was massively redesign, it must have been done in a rather short period of time... so it remains questionable how much changes were made.

 

As for the "engineer rumor": Given the source of this rumor, I would completely discard it until another source supports it.

 

 

Based on drawings of the Challenger 1 tank, the frontal turret armor modules are sloped at 26-28°, but the turret front of the M1A1 HA is sloped at 28° (in front of the gunner's sight) and 36° (in front of the loader's place) - that means that the gain in protection when attacking at 0° instead of 30° from the turret centerline is different (i.e. the left turret front module of the M1A1 HA would gain less additional protection compared to the right turret front module), which complicates the matter. Also note that modern armor arrays thanks to including NERA sandwiches as well as potentially certain materials like glass and ceramics do not provide the same amount of efficiency at all angles. The armor could be designed to provide maximum efficiency when being hit at 30°, thus the protection could be a lot more homogenous along the frontal arc.

 

-snip-

 

With the CR1 protection numbers, I personally did not believe the "engineer rumor" myself. I just did not believe that British could compose an armor array that would offer a superior armor efficiency compared to their US and German counterparts.

 

There are quite a few issues:

 

1) The British are aware of the threat the 125 mm guns pose by no later than 1981.

 

2) The armor array of the Challenger 1 was never upgraded as far as i know while it was in service (1983-1997).

 

If these two statements are true we need to ask the following question:

 

If the Challenger 1 turret offers a similar protection level like their German and US counterparts, why were the armor packages of the Challenger 1 never replaced while in service ?

 

The British thought it was necessary to up-armour their Chieftains but they did not find it necessary to up-armor their Challenger 1s by replacing the old armor packages with new ones?

 

Either the armor package was replaced or the original armor package was considered adequate enough to already offer enough protection to deal with the 125 mm ammunition.

 

I really wonder where the Armed Forces Journal Author  got his numbers from. 

 

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51 minutes ago, Mighty_Zuk said:

How did they even make up these numbers? Some of them seem to be correct, or at least not too far fetched, but many seem to be exaggerated intentionally.

 

As mentioned on the site; the information comes from "... posts on Tanknet the premier source of tank discussion online. Also from Stephen Zaloga's various works on Russian MBTs, GSPO forum, Hilmes' books, Hunnicutt Patton and Abrams, Janes IDR and the NII Stali website. "

 

Some of the values shown on the site do correspond to values revealed in recent documents, while others are rather more questionable (e.g.: Challenger 1 Lower hull front of Mk1/3 version had ERA = 520mm KE).

 

 

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1 hour ago, Laviduce said:

1) The British are aware of the threat the 125 mm guns pose by no later than 1981.

 

They were aware of a 125 mm threat in 1978 already, when they wanted the MBT-80 to have 435 mm steel-equivalent protection against KE rounds. When the Leopard 2 was redesigned after the US trials of the Leopard 2AV, the 125 mm gun also became known. However this doesn't mean that changing the complete design in order to allow a greater armor weight was an option. Staying within the weight limits did not permitt a Leopard 2 with protection against 125 mm APFSDS ammo from all ranges, so it was not fitted. Staying within the weight limit made it also impossible for the MBT-80 to reach full protection against 125 mm APFSDS ammo in 1978.

 

1 hour ago, Laviduce said:

2) The armor array of the Challenger 1 was never upgraded as far as i know while it was in service (1983-1997).

 

Yes, but you need to think about it in a different way. An alternative to upgrading the Challenger 1's armor already existed with the Challenger 2, which was ordered in 1991 and first delivered in 1993. Let's take a look at it from another perspective: The Leopard 2 entered service in 1979, a new armor package was first introduced in 1988. That's nine years with the old armor package, which did not provide enough protection to resist most types of 125 mm APFSDS ammunition. Even after the new armor package was introduced, it was not fitted to older tanks, as upgrading them would take time and money while also reducing the production of new Leopard 2s.

 

If the British army or the FVRDE decided to that the Challenger 1's armor was lackluster after nine years (just like the Germans did with the Leopard 2), then they already had ordered the Challenger 2 at that time. So upgrading was not necessary. In fact the British army started a program to replace the Chieftain tank in 1987, for which the Challenger 2 was designed and other tanks (like the Vickers Mk 7/2, the Leopard 2 and the M1 Abrams) were evaluated. So upgrading the Challenger 1's armor had a low priority. After the dissolution of the Soviet Union in 1991, there were even less reasons to upgrade the armor of the Challenger 1.

 

1 hour ago, Laviduce said:

Either the armor package was replaced or the original armor package was considered adequate enough to already offer enough protection to deal with the 125 mm ammunition.

 

No, timing might have meant that no armor replacement was done, even though the main armor did not offer enough protection against 125 mm rounds. Just look at the picture you posted earlier regarding the Stillbrew armor: according to British performance estimates, the 125 mm APFSDS ammo did not manage to penetrate 500 mm RHA even at point-blank range! That kind of defeats the purpose of having armor providing protection equal to 500 mm steel armor against APFSDS ammo; 475 mm would already be enough (because the British underestimated the penetration power of the 125 mm gun) to deal with 125 mm tungsten-cored rounds at 0 metres; more modern ammunition then would be defeated at longer ranges. 

 

1 hour ago, Mighty_Zuk said:

How did they even make up these numbers? Some of them seem to be correct, or at least not too far fetched, but many seem to be exaggerated intentionally.

 

Most of these values come from Paul Lakowski, the author of Armor Basics and one of the makers of SteelBeasts. Armor Basics pretty much shows how he created these numbers: he completely skipped the research phase, instead he simply invented weird armor arrays based on incorrect thickness estimates and a very limited number of research papers (because every tank is protected by ceramic armor!).

 

There are some forum posts (IIRC in the old SteelBeasts forums) showing his faults in case of the Leopard 1. First of all, he came to the conclusion that the armor thickness is actually much greater than it actually is, because something "looked"  to be XYZ mm thick, then he added the slope and the basic Leopard 1 suddenly had 200-250 mm thick cast steel turret armor (instead of 130-140 mm). Being cast armor and due to the "edge effect", this would lead to 180-200 mm protection... That's why he wrote that the Leopard 1 is a MBT turret on a light tank hull in Armor Basics. After that, he somehow "found out" that the Leopard 1A1A1's add-on armor consists of Lexan (polycarbonate) rather than being high-hardness perforated steel paltes with rubber coating as it was later revealed. This is why the  Leopard 1A1A1 does offer only a minimal increase in protection on this silly website. Last but not least the Leopard 1A5 (even though it doesn't include any upgrades to armor IRL) would utilize ceramic armor tiles, which look identical to the Lexan armor that he though was fitted to the Leopard 1A1A1. In his mind (maybe because some "expert" told him that in some forum), the armor would be only fitted in case of combat, so nobody can distinguish the Lexan and ceramic armor. This ceramic would allow the Leopard 1A5 to reach 450 mm vs KE... :unsure:

 

They were clever enough to remove all old topics when they changed/updated the forum software.

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Something interesting from the net bout old concepts of future tanks:
British MBT-95 Concept B
0068Ayuagy1fc6puxr2ulj30qr0eftnd.jpg
0068Ayuagy1fc6f4vtf0ij30ny0o2dk3.jpg
Some info bout Leclerc's development history and it's prototypes
0068Ayuagy1fc6caf4g2vj31kw23vb2b.jpg
AS 22
0068Ayuagy1fc6cc044tej31kw16ou0z.jpg
AS 40
0068Ayuagy1fc6cbxlj41j31kw16okjn.jpg
0068Ayualy1fc6opoewg2j30y20k3agm.jpg
Source and some photos with other countries concepts
https://media.weibo.cn/article?id=2309404069024974698593&jumpfrom=weibocom&featurecode=20000180&oid=4088587316553107&lfid=1076031728875812&luicode=10000370

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1 hour ago, LoooSeR said:

I find funny how he put watermarks on BTVT drawings.

This is my blog , I was not very  familiar with this platform at that time, the system put Watermarks automatically but I didn't know about it, if necessary I will delete this post, sorry about that.

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7 minutes ago, Molotav_DIGITANK said:

This is my blog , I was not very  familiar with this platform at that time, the system put Watermarks automatically but I didn't know about it, if necessary I will delete this post, sorry about that.

I know that it is your blog, although it is strange that it puts watermarks on its own. I don't care much, as pics are from Andrey's site, i just found it slightly funny.

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1 hour ago, Molotav_DIGITANK said:

This is my blog , I was not very  familiar with this platform at that time, the system put Watermarks automatically but I didn't know about it, if necessary I will delete this post, sorry about that.

Oh i am sorry, i didn't knew. Don't delete this post, post more

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2 hours ago, Molotav_DIGITANK said:

This is my blog , I was not very  familiar with this platform at that time, the system put Watermarks automatically but I didn't know about it, if necessary I will delete this post, sorry about that.

 

No problem!

 

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On 4/9/2018 at 6:58 AM, SH_MM said:

What are you exactly looking for? The T-72 protection requirements are taken from Zaloga and a Russian website.

 

If you still have the link to the Russian post, I'd love to check it out. I find Zaloga to be very hit or miss, so I'm hoping there's some additional support for that protection level... it does certainly sound familiar, but I'm having trouble tracking down where I read something similar.

 

Cheers

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On 4/9/2018 at 12:58 PM, SH_MM said:

As for the Challenger 1's armor: 500 mm steel-equivalent protection might be possible, given the date of introduction and its huge weight, but it certainly is not set in stone. Confirmed is that the Shir (Iran) 2, which was used to develop the Challenger 1 tank, had a protection level of 325 mm along the 30° frontal arc (?) in 1978. Given the power-to-weight ratio listed in the British documents, the Shir (Iran) 2 tank weighed 63 to 64 metric tons, just as much as the Challenger 1. In so far the British engineers would have needed to completely redesign the armor array to reach the desired level of protection. In 1978, a protection level of 435 mm vs KE (as achieved on the MBT-80) was considered to be "enough". Originally the Shir (Iran) 2 was to be delivered in 1979 and 1980; but the deal was canceled with the Iranian revolution of 1979. The decision to not continue the development of the MBT-80 was made in July of 1980, the first Challenger 1 pre-series vehicles were delivered in 1982; so if the armor was massively redesign, it must have been done in a rather short period of time... so it remains questionable how much changes were made.

 

As for the "engineer rumor": Given the source of this rumor, I would completely discard it until another source supports it.

 

 

Hello

 

I was curious if a possible explanation for the large jump in alleged protection levels of the Challenger 1 over the shir 2 in such a short period of time could be attributed to the inclusion of ceramics and other such materials.

 

Spoiler

Capturar3.thumb.JPG.41ed86a9f7da90fbc7b6

 

5ac4a9fe3af82_Capturar4.thumb.JPG.f865a8

 

Capturar5.JPG.de42ffe6838fee21b27da8adfb

 

image.png.288383e1b91b8574e0650b4b69d45a

 

5ac4a9b089652_Capturar2.JPG.e3a0e59d2242

 

Capturar.JPG.b277ec82b8f22d1154d716c5056

 

Something from Ed Francis at the Bovington tank museum on the matter

 

Spoiler

Once again they are confusing Chobham with early Burlington. Burlington was steel and rubber layers only occasionally mixed in with aluminium plates (The Iraqi Enigma was very similar) Early chobby has ultra-high-temperature ceramics, steels, rubber and an abrasive backing filler (like Kevlar) super compressed under great pressure. This causes it to bulge when hit somewhat forming a natural NXRA type reaction and abrades the round. Modern armour is all about dispersing the energy of the incoming round, in fact manufactures still use RHAe in the same way palaeontologist uses busses to discuss the mass and size of dinosaurs. It’s to make it easier for the layman to understand.
If a round strikes with 20MJ of energy then the armour need to disperse 20MJ of energy before it can reach the interior of the vehicle. Ceramics such as Boron Carbide are very hard but brittle. As the round pierces the outer layer of face hardened steel the ceramics shatter this in turn help to disperse some of the energy – as the round carries on (picture in slow mo.) the round is undergoing massive forces. With the rear of the rod having considerably more energy retention than the front of it. This causes the round to actually bend a bit at a very fine level. The interaction between this and multiple layers of shattering ceramics and shifting steels deforms the rod further releasing yet more energy until it is spent. Contrary to popular opinion APFSDS rounds do not ricochet they will either perforate their target or shatter. Those seen on range footage hitting the ground is the rear tracer half spinning off in most cases.
A good way of imagining what’s happening is to imagine a block of butter (steel) sandwiched between two layers of bread. Now poke you finger though quickly- no issues. Now fill that butter with shards of glass and try it again – though multiple sandwiches. See how your finger now looks all deformed and tattered like a leftover dog’s dinner.
Regarding shaped charge attacks it’s slightly different, a SC does not melt armour as some would have you believe and in fact the temperature is only around 660 degrees when measured. The Jet of material is hydrodynamic and undergoing extreme plasticity being both a solid at the core and a liquid/gas the further you go from the centre. As this perforates using KE the outside of the jet interacts with the base material which flows back in on itself (a bit like trying to dig though very fine sand) the more material there is to go through the thinner the jet gets. This is known as fist to finger deformation. However conventional steel is not particularly good at stopping this. In fact as the depth of perforation is inversely proportional to the square root of the density of the target material; low density material offers better protection than steel relative to its weight. (See Diesel fuel as armour) in the case of ceramics the material does not flow like steel would and disrupts the jets shape and path causing massive energy loss and the deformation of the stream resulting in a loss of perforation.
Later marks of Chobham, Mk 2, 3 and newer versions such as Dorchester 1 & 2 follow a very similar concept with differing materials, and arrangements inside. I am highly suspicious of Gaijins claims to have any accurate information on this and it certainly did not come from any British authority on the matter as it is still OSA. Challengers Chobham armour extend over the turret front and first 1/3 of turret sides. Over the glacis and first 1/3 of the lower hull. It does not have Chobham on the sides etc. as it was never built to be a particularly good tank, which was set aside for MBT-80.

 

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On 4/22/2018 at 1:02 PM, LULZ said:

I was curious if a possible explanation for the large jump in alleged protection levels of the Challenger 1 over the shir 2 in such a short period of time could be attributed to the inclusion of ceramics and other such materials.

 

I don't think there is a possible explanation, because people are beginning the argument from the wrong direction. People are making assumptions about the protection level, then try to find sources supporting it - i.e. first comes the thesis, then sources are searched to support it. That's the wrong way to start research - saying "the Challenger 1 needs to have 500 mm RHAe against KE" and then gathering all sources that say somewhat related. I can understand that Laviduce expects a high level of protection based on the thickness of the Chieftain's Stillbrew armor package and based on the greater weight of the Challenger 1 MBT - it could have a protection level of 500 mm vs KE. But we have no confirmation to these theories. With British documents showing that the estimated penetration of 125 mm tungsten-cored APFSDS ammunition was only 475 mm at point blank, I have serious doubts that a protection level of 500 mm or more against APFSDS  was required - that's simply not how tanks are designed.

 

The Challenger 1 development was pursued at a different timeframe than the Chieftain upgrade with Stillbrew armor, thus the requirements were different; in so far "just" 400-450 mm vs KE might be a lot more realistic based on the requirements for the MBT-80 project and the data of the Shir 2, assuming the armor package was improved over the latter tank. The Challenger 1 was approved in 1980, the Stillbrew upgrade in 1984. A lot can happen in four years of the Cold War. Even the Chieftain with Stillbrew doesn't reach protection comparable to 500 mm rolled armor steel vs APFSDS ammo, because cast steel provides up to 20% less protection than rolled armor steel.

 

Ceramic armor is not a magical solution to all problems. The T-64A used ceramic armor, yet it protection level was rather limited compared to later tanks.

 

On 4/22/2018 at 1:02 PM, LULZ said:

Capturar3.thumb.JPG.41ed86a9f7da90fbc7b6

 

 

This is wrong. The cited book - at least in its original German version - does not say what is claimed in the first paragraph of this screenshot of "Armor Basics". While the first quote can be found pretty much verbatim on page 76, the second part - i.e. "the ballistic effectiveness of the compouned armors against KE penetrators shows an improvement of only 1.2 to 1.4 over homogeneous rolled steel plate (incontrast to a factor of  2 against shaped charges." - cannot be found on page 76 or 77 of the original book. I have never read the translated version, but I am fairly certain that it doesn't say what is claimed previously.

 

On page 75, the claimed efficiency values (1.2 to 1.4 vs KE, 2 vs shaped charge) can be found: but that is in a paragraph on the armor protection of the T-72! The "factor 2 against shaped charges" is meant to be the mass-efficiency value and is based on a Swiss assessement from a 1982 issue of the Allgemeine Schweizerische Militärzeitschrift claiming that the T-72's hull armor is weight equivalent to a 120 mm steel plate sloped at 70° and provides twice as much protection against shaped charge ammunition as steel armor of the same weight. The same article also includes statements about the supposed performance of the T-72's armor against KE ammo: the article claims that the T-72, M1 Abrams and Leopard 2 use special armor and certain types of special reach a efficiency against KE ammunition of 1.2 to 1.4 per thickness (!). The T-72, which was believed by the Swiss authors to feature a 300 mm line-of-sight thick array of such armor (in reality it had a simple cast steel turret with a thickness of up to 500 mm, while the hull armor has an effective thickness of 547 mm), would then reach a protection level of 360 to 420 mm.

 

IvMcvXF.png

 

We know for fact that the T-72's armor neither reaches a mass efficiency of 2 against shaped charges nor that it provides a thickness efficiency of 1.2 to 1.4 agianst kinetic energy ammunition. It is a false assumption based on incorrect data from a time when the T-72 was still a mystery to NATO and non-aligned countries.

 

Everything else - regarding the effectiveness of ceramic armor - is not related to the Challenger 1. It is pure, unreferenced speculation that the tank would be fitted with such armor, even though it has been proven that Chobham is (mostly) based on spaced NERA sandwiches. Based on a number of declassified documents on the development of Chobham armor, there apparently were more than a dozen different Chobham armor arrays being tested in the early 1970s. Some of them were merely improved versions of earlier designs, others were created to experiment with new concepts (e.g. there was on Chobham armor array that incorporated high explosives similiar to integrated ERA). There might have been some Chobham arrays with ceramic component in them and this development might have lead to the array adopted on the Challenger 1  - but there is no proof for this; even if they are included, ceramics would only play a minor role. CeramTec ETEC, one of the market leaders in Europe for manufacturing ballistic ceramic materials, includes photographs of the Leopard 2 in its flyers, suggesting that some ceramic elements might be part of the armor array.

 

However suggesting that the Shir 2's 325 mm steel-equivalent protection against APFSDS rounds could be increased to 500+ mm just by incorporating ceramic materials seems wrong. Burlington and Chobham are different names for the same thing - there are numerous files using both names to refer to the same armor arrays. According to the British DSTL, modern armor arrays designed to provide protection against KE and HEAT rounds follow a three-stage layout, i.e. they consist of:

  1. a distrupting stage to break KE pentrators and shaped chage jets
  2. a distrubing stage, which makes sure that the particles and fragments of the broken penetrator change direction and yaw angle
  3. an absorbing stage, which stops the fragments from reaching the interior and absorbs the kinetic energy

The options for designing the second stage are pretty much limited to different types of spaced multi-layer armor or other types of reactive armor; based on known armor arrays - such as the T-72B's armor and the M1 Abrams' armor, the distrubing stage usually takes up at least half the available armor volume. The first stage is often based on a reactive armor (see the wedge-shaped armor of the Leopard 2A5 or the Kontakt-5 ERA on late Soviet MBTs), although it could also be made using high-hardness steel, perforated armor or ceramic plates (the latter two variants being common on lighter vehicles, because this armor is more efficient against short, bullet-shaped penetrators). The absorbing stage also can include ceramic materials, but will always include a steel layer (which serves as strucutral support) and potentially kevlar, polymers or other materials.

 

In case of the M1 Abrams, the absorbing stage of the hull armor was a rather simple steel plate.

 

F5nVTZU3.jpg

 

So simply adding ceramics to the armor won't drastically change the protection. The Challenger 1 would require a completely different armor array, which would suffer from the typical problems of ceramic armor against large calibre ammunition, such as a relatively low efficiency, low multi-hit capabilty and problems with cost and manufacturing. Armor consisting of layered aluminium oxide with polymer backing and steel enclosure provides the same protection against shaped charges as steel of the same thickness - thus a Challenger 1 with 700-800 mm frontal armor at most would be quite vulnerable to shaped charges.

 

On 4/22/2018 at 1:02 PM, LULZ said:

 

The "Armor Basics" document from which these snipplets are taken is known to be outdated and incorrect in various aspects. The author speculated too much and used false premises to generate his values - armor thickness, armor weight and layout are often wrong. Here for example he ignored that the Challenger 1 turret is meant to provide protection along a 60° frontal arc (30° to each side of the turret centerline), but the Chieftain was designed with protection along a 45° arc only! Thus his whole idea of using the weight difference to scale the equivalent armor weight of the frontal armor is incorrect. He also claims that a 15% increase in steel mass would result in a steel mass equivalent to a thickness of 50 cm - this would mean that in his beliefs the Chieftain was having an armor thickness of 434 mm, which it does not have in reality - the thickness of the frontal turret armor of a Chieftain is about 240-280 mm according to sources posted earlier in this topic.

 

On 4/22/2018 at 1:02 PM, LULZ said:

Something from Ed Francis at the Bovington tank museum on the matter 

 

I don't know any "Ed Francis" and see no reason why his writing should be relevant to this discussion. Seeing that the origin of this quote is a post on the Warthunder forum, which wasn't even written by him, but somebody claiming to have spoken to him, I would be rather careful. This is a big pile of unreferenced claims, that in some cases is rather easy to disprove. It is all speculation with no sources.

 

If Burlington and Chobham were two different things, why would official US and UK documents use both names like synonyms?

 

20131231_112142.jpg?w=700&h=

 

There are dozens of documents on the development of Chobham/Burlington armor, which are using both names; they also use "Chobham spaced armour" and similar terms disproving the claims that supposedly were made by Ed Francis. And this is how the Chobham spaced armor is shown in the same document - no trace of ceramics!

59c2b522643c7_ChobhamfrontplateChieftain

 

Ceramics themselves do not bulge, but rather break; the elasitic backing behind the ceramic tiles will bulge. Ceramics are not suited for NERA sandwiches as long as multi-hit capability matters,

 

Even if this forum poster had asked Ed Francis on the topic and he let him type on the Warthunder forum with his account, I don't see why this name would result in the text being relevant to us. According to a quick google search Mr. Francis is a volunteer at Bovington, not an expert on AFV design and armor technology. Given that there seems to be no special credentials to his name and that Bovington still has a plaque citing incorrect armor values in front of the Chieftain tank, I do not consider this to be a source.

 

On 4/23/2018 at 5:35 AM, Lord_James said:

How many M1 Abrams were irrecoverably lost in operation desert storm/shield? 

 

There are no exact figures, which is also related to the problem of "irrecoverably lost" being a philosophical question. However the Abrams supposedly did perform very well in ODS. There were 14 Abrams tanks with DU contamination after being struck by DU rounds or on-board fire, for which the US Army lacked procedures and equipment to deal with. If they recovered these later or not is unknown to me.

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981311_600.jpg

 

The British military believed that its ammo was incapable of defeating the T-80 during the Cold War,  but it was enough to deal with the T-64. Given that this document is from 1986, Stillbrew armor might not have been adopted on the Chieftain yet, hence the statement about the Chieftain's armor being defeated by all modern Soviet tank guns (which I suppose means 100 mm, 115 mm and 125 mm guns).

 

The Challenger 1's frontal turret armor is claimed to be comparable to Soviet tanks with ERA. That would most likely be the T-64BV, T-72AV and T-80BV, given the fact that NATO learned about the T-72B in ~1988 (at least the official NATO codename for it was "Soviet Medium Tank 1988") and T-80U in 1989 (US/NATO codename M1989). This would suggest that the Challenger 1's frontal armor might be 450-500 mm vs KE and ~1,000 mm vs shaped charge warheads.

 

andrei-bt.livejournal.com/788654.html

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4 hours ago, SH_MM said:

The British military believed that its ammo was incapable of defeating the T-80 during the Cold War,  but it was enough to deal with the T-64. Given that this document is from 1986, Stillbrew armor might not have been adopted on the Chieftain yet, hence the statement about the Chieftain's armor being defeated by all modern Soviet tank guns (which I suppose means 100 mm, 115 mm and 125 mm guns).

 

The Challenger 1's frontal turret armor is claimed to be comparable to Soviet tanks with ERA. That would most likely be the T-64BV, T-72AV and T-80BV, given the fact that NATO learned about the T-72B in ~1988 (at least the official NATO codename for it was "Soviet Medium Tank 1988") and T-80U in 1989 (US/NATO codename M1989). This would suggest that the Challenger 1's frontal armor might be 450-500 mm vs KE and ~1,000 mm vs shaped charge warheads.

 

andrei-bt.livejournal.com/788654.html

 

Thanks for sharing another fine doc. More evidence pointing broadly in the same direction. (The links below are also all in this thread IIRC).

 

I interpret the 1988 UK doc for KE protection as: Leo-2A4 < Stillbrew Chieftain < CH1 < CH2 < M1A1HA. The top number in the range is likely 600mm, and yet the CH2 should have "significantly" better KE than the CH1. IMO, one should assume the lowest possible KE for Stillbrew & CH1. Even 500 seems too high to fit into this 'formula'.

 

I can't find contemporary Soviet CE protection estimates from the UK. The US low-end in 1987 was perhaps 500-600. (Way back in time, the MBT-80 CE level of 600 IIRC was deemed inferior to the XM1, but sufficient nonetheless). If the UK had already fielded superior CE protection to the M1, I'd think they'd have mentioned it in the 1988 doc. Finally there is the "roughly comparable" statement, for which a tank of 500/1000 KE/CE is possibly too much of a stretch. All evidence suggests that 1986 models of the Leo-2 & M1 were pretty far below that. It's indirect reasoning, but I take this as low-end CE for the CH1... and a CH2 with 900 CE at best--i.e. similar enough to the M1A1HA that it was not worth remarking upon one way or the other in 1988.

 

P.S. The 100mm ..BM8 and ..BM20 rounds would be appropriate candidates to defeat the pre-Stillbrew Chieftain I'd think.

 

 

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1 hour ago, Olds said:

I interpret the 1988 UK doc for KE protection as: Leo-2A4 < Stillbrew Chieftain < CH1 < CH2 < M1A1HA

 

As pointed out earlier in this topic, the UK tested the early production model of the Leopard 2 with the initial armor package. Based on the leaked data and some reasonable assumptions (i.e. that the largest physicial thickness provides most protection), it would provide about as much protection as 430 mm armor steel at the turret front. The Chieftain with Stillbrew has 500 mm cast steel (with a bit of rubber inbetween), thus protection could range from 400 to 475 mm equivalency to rolled armor steel based on available figures regarding the efficiency of cast steel. However the Chieftain's turret was designed to provide protection at a 45° arc, while the Leopard 2's turret was meant to have a protected 60° arc.


The Leopard 2A4 production model from 1988 seems to have armor protection comparable to 540-550 mm steel at the turret front and about 425 mm at the hull front, which is roughly comparable to the T-72B and overall superior to the Chieftain with Stillbrew armor.

The British sources do not state that the Challenger 1 is better protected than the Chieftain with Stillbrew armor at the turret front, although this assumption seems to be overall reasonable. The M1A1 HA is better protected only at the turret front, penetrating the turret sides from within the 30° arc is possible with APFSDS ammo capable of penetrating 480 mm steel armor. The hull is also rather weak, which is why I wouldn't really consider the M1A1 HA overall superior, unless the British hull is as bad.

 

1 hour ago, Olds said:

Way back in time, the MBT-80 CE level of 600 IIRC was deemed inferior to the XM1, but sufficient nonetheless

 

The document actually says that the MBT-80 has higher protection against ATGMs and RPGs (or rather: it has a lower probability of being destroyed by ATGMs/RPGs) than the Abrams, as long as the hull is hidden behind terrain. The probability to "kill" a MBT-80 in hull-down position with an ATGM is 21%, while the probability to destroy it in a hull-down position with an RPG is 11%. The respective values for a XM1 Abrams in hull-down position are 23% for ATGMs and 17% for RPGs.

 

The hull armor of the MBT-80 was worse than that of the XM1 Abrams in particular against shaped charge ammunition, which probably also was true for the Challenger 1 and Challenger 2 (without add-on armor or ERA covering the LFP).

 

1 hour ago, Olds said:

If the UK had already fielded superior CE protection to the M1, I'd think they'd have mentioned it in the 1988 doc.

 

The document specifies that the "recently announced uparmouring of Abrams" was expected to give this tank better protection against KE. To me this seems to imply something different: if the armor upgrade also resulted in better protection against shaped charge, it should be mentioned aswell. I guess we have to find better sources in the future to evaluate which tank was better protected against shaped charge ammunition.

 

The Chieftain Mk 5/2 project from 1970 already was designed to resist large calibre shaped charge warheads (a 5.0 inch warhead and a 6.0 inch warhead with 60° cone angle), that were capable of penetrating 23 and 28 inches of steel armor (584 and 711 mm) which is more than what the XM1 Abrams was designed to resist.

 

2866029712_760c7bc76e_b.jpg

 

 

 

 

 

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