SH_MM

Trophy on the Abrams weighs 2.2 tons. There definetly is something fishy with the proclaimed weight of Trophy for the Merkava 4.

According to the following drawing, the gun mantlet armor is actually a lot thinner, because the 420 mm thickness are also the trunnion of the main gun! The Type 90 tank seems to be rather poorly protected.

I cannot remember either. However in another forum, where somebody posted all forums of his visit, he claimed that this was the 105 mm DM53.

(posted by Wiedzmin on the Tank-Net) The Challenger 1 has enough armor to stop a 125 mm APFSDS at about 1,000 metres distance. Given that the British estimated a penetration performance of 475 mm steel armor at 0 metres for a 125 mm tungsten-cored APFSDS round, it seems likely that the Challenger 1 has 400-450 mm protection vs KE; this also would match the statement that the Challenger 1 has protection roughly equal to a T-64BV, T-72AV or T-80BV tank. The Challenger 2 design - not necessarily identical to the production model - at some point of time was to have improved hull armor; there is no mention of upgraded turret armor (at that time). That leads to: XM1 Abrams - resists 115 mm APFSDS at 800 - 1,200 metres (official requirement), penetrated by 125 mm APFSDS even at 4,000 metres (British claims) Leopard 2 - turret resists 115 mm APFSDS at 1,000 metres & 125 mm APFSDS at 1,500 metres (Swiss estimates) Challenger 1 - turret resists 125 mm APFSDS at 1,000 metres, hull weaker Challenger 2 - turret and hull resist 125 mm APFSDS at 1,000 metres (design specifications) Chieftain with Stillbrew - turret resists 105 mm APFSDS point blank and 120 mm APFSDS at 1,000 metres

Most of the German 105 mm APFSDS ammunition was made by Diehl BGT Defence rather than Rheinmetall; apparently Diehl produced the 105 mm DM13 APDS (licence production of a British design), the 105 mm DM23 APFSDS (licenced copy of the Israeli M111 "Hetz"), the 105 mm DM33 APFSDS (IMI M413) and the 105 mm DM63 (IMI M426). The 105 mm DM43 APFSDS was made by Rheinmetall however. I don't know who made the 105 mm DM53, maybe it never entered full service and was skipped like the 120 mm DM43 APFSDS. There is a projectile claimed to be from a 105 mm DM53 round on display in a German museum.

I am fairly certain the quoted contract price for the Estonian CV90s is wrong. 625,000 Euro might be the cost per CV90 hull.

T-72B3 has the same basic side skirts. Claimed to be steel + two layers of glass-fibre reinforced plastic + steel with integrated ERA panels (and optional heavy ERA mounted in bags).

It is ERA with limited exploding area. I.e. there are documents suggesting using small pellets of explosives inside another elastic material (such as rubber or GFRP). Only one or two pellets will explode during penetration, limiting the destroyed area (in contrast to blowing up a complete ERA tile).

I posted about this on another forum quite a while ago, so you may already know this: The company FWH manufactures cast armor parts for German AFVs. It offers three quality classes. Quality class "P" with a hardness of 350 to 380 on the Brinell scale was used for the Leopard 2 to 2A3 (I suppose the early batches of 2A4 tanks also received casts parts of the same quality class). Quality class "Q" with a hardness of 380 to 420 HB was used on the Leopard 2A4, 2A5 and the 2A6 models for Greece and Spain. The quality class "R" with a hardness of 480 to 520 HB is used for the Puma and Boxer. Most German combat vehicles make use of welded armor, so this info is rather meager. However the Boxer uses 45 cast armor parts made by FWH with a size of up tp 1,600 mm. On the Leopard 2 cast armor elements might be used for the gun mount, the mounting system for the suspension elements and maybe parts of the hatches. But this information gives a general idea about what steel was used for this tank and how protection was improved from the earlier models to the later Leopard 2A4 batches and the following models. Welding is done austenitic for steel elements of quality class "P" and ferritic for the quality classes "Q" and "R". There is a document suggesting that the welded steel plates for the Leopard 2's basic construction were delivered by the Stahlwerk Geisweld. The steel is branded "HFX 130" and has a thickness ranging between 5 and 45 mm depending on location. Unfortunately there is no HFX 130 steel being advertised anymore. An interessting fact is that the Stahlwerk Geisweld is nowadays owned by Schmolz und Birkenbach, which also owns the Swiss company SteelTec. While Stahlwerk Geisweld seems to be focused on manufacturing stainless steel for industry applications, SteelTec offers a product called "HSX 130". Given that the "HF" stands for "hochfest" (German for "high strength") and "HS" also stands for "high strength", both of these steel alloys might be the same. HSX 130 steel is offered with a maximum thickness of 45 mm (like shown in the German document mentioning HFX 130) and has a hardness of 395 HB on average (tensile strength ranges from 1,250 to 1,400 N/mm². This might be used on the Leopard 2, given that flyers from Krauss-Maffei talked about the high quality steel used for the tank. ___ German Leopard 2A6MA2 being handed over to the Netherlands:

DE 20 2016 104 939 U1 is a patent from Rheinmetall about the 130 mm smoothbore gun. In particular the patent is about a new gun with greater calibre designed to fit into the space of an already existing gun system such as the 120 mm smoothbore gun. The idea is that the design results in the room for the ammo storage being the limiting factor for gun upgrades. From the claims: existing gun must be swappable/replaceable new gun has a larger calibre the maximum catridge diameter must be nearly the same (not to be confused with the calibre of the projectile) the chamber of the new gun is longer how much of the chamber is used is depending on the ammunition type and propellant charge (I suggest that might mean that HE ammo has shorter catridges?) the new gun has a longer recoil path the new gun is designed for a MBT 130 mm gun details. 120 mm and 130 mm chamber comparison. So it seems that it is possible to upgrade the Leopard 2 with the 130 mm smoothbore gun, but it would require an autoloader and a new storage rack for the longer catridges.

You previously wrote I would speculate too much on the weight of the tanks, yet you are making even more speculations. Your sources are inconclusive and thus one should be careful with trying to make any statements based on them. First of all, the British document states that the KE protection for the Abrams would reach a level of 320 to 340 mm protection against APFSDS rounds along the protected frontal arc. Given that the hull front has its minimum armor thickness of the frontal hull is at 0° (while the side armor wasn't altered), it should not have a protection level of "350 mm KE minimum". In fact the M1A2 offered to Sweden has a protection level of 350 mm along the frontal arc of the hull - this tank has no DU armor, but that doesn't matter because only five Abrams tanks were ever created with DU armor protecting the hull. We know that the M1IP and the M1A1 feature upgraded hull armor, which can be seen by looking at the location of the weight demonstrators. This leads to the conclusion that the M1 Abrams did not have 350 mm KE minimum for the hull, but rather 320 mm. The table from the British documents lists a single value for armor protection for the Leopard 2, you are speculating what this value exactly means. First of all, "at [the] normal" can refer to the armor modules - as suggested by you - or to the tanks. Hitting a tank at normal means hitting the "front side" at perpendicular angle (the side of the tank not being affected by the shape of the armor). Against your assumption speaks the fact that the Centurion, Leopard 1 and T-62 are not listed with the respective armor thickness values they'd have when the armor was hit at the normal from within the 60° frontal arc (Leopard 1 for example would have some 50-70 mm thickness, the T-62 some ~150 mm). This implies that "at normal" means "hitting the tank directly from the front". You are assuming that this values would refer to the turret armor; but there is no proof for this. The document doesn't say anything about the table being limited to the turret, in fact it lists the hull armor of the Centurion, the Leopard 1 and the T-62! So even if this would refer to "hitting the armor modules at normal", it still could be a value for the hull being hit at 0°. Do I think that the Leopard 2 must have a protection level of 400 mm or greater at the turret when hit from a 30° angle? No, I don't think it has to. It might have a protection level in the high-300s; but I think we should find sources before making assumptions. We however know for fact that the Leopard 2 has a protection level of ~430 mm steel against KE rounds at the turret when hit directly from the front, because this value is derived from an official table by the manufacturer. So your "350 at 0" is already a false premise. You seem to be eager to "prove" that the Leopard 2 has worse frontal armor than the M1 Abrams; you are ignoring some facts, which speak for the Leopard 2 having better frontal armor (such as the greater armor weight and thickness alocated to the turret front) and you are basing everything on a single source, which leaves too much room for interpretation. As I previously stated, it seems to refer to the protection of the hull front - this would match the data from the Swedish leaks and the physical armor thickness (the hull armor of Leopard 2 and M1 Abrams has nearly identical thickness) and is supported by the values of other tanks matching their hull armor thickness. The data from the Swedish leak is inconclusive regarding the protection level of the Leopard 2, when attacked from various angles: As you can see, the surface area with a protection level of 400 mm or more is always larger when attacking the tank from angles other than 0°. The only question that remains is: Which places reach this protection level? The document doesn't tell anything about that, it also doesn't specify wether the area (100%) is limited to the crew compartment or not. If the latter is the case, it seems easily possible for the turret frontal section to also to be part of the protected area. Most likely the hull frontal armor reaches a protection level greater than 400 mm when hit at 20° or 30°, if the frontal hull armor is actually included in the relevant surface area. The Leopard 2's turret armor has a frontal armor thickness of about 860 mm at the left turret cheek; given that the turret front is sloped at 34° in the horizontal plane, it will have a greater armor thickness when hit at 30° angle than the hull armor at 0° - overall the armor thickness might be comparable to that of the Abrams of 0° (unfortunately nobody has published proper measurements of the Abrams, but supposedly the early production model had some 700 mm physical thickness when hit at 0°). You should keep in mind that the Leopard 2(AV) was designed to resist the 105 mm smoothbore gun firing APFSDS ammo (i.e. the same projectile as used on the 120 mm DM13 with lower velocity) from unknown range. This round has a slightly higher MV and a longer & thicker tungsten penetrator than the M735 APFSDS, which is claimed to penetrate more than 300 mm steel armor. ___ Moving back from the armor and more to the general topic: Something regarding mobility: According to the French topic, the Leclerc squeezes 1,143 effective hp out of its 1,500 hp engine. The M1 Abrams reaches a1,232 hp net output of its AGT-1500C gas turbine, also some older discussion suggest that it might have only ~1,000 hp at the sprokets. The Leopard 2 seems to be less efficient in this regard, managing to get only 1,070 hp to the sprockets according to W. Spielberger. Leopard 1 gets 630 out of 830 hp to the sprockets. Maybe that is why the German army wishes for a 1,200 kW engine on future Leopard 2 models; however the published acceleration data suggests that the Leopard 2 beats the Abrams to 32 km/h. Regarding FCS: In 1987 the Saudi Arabian Kingdom tested the AMX-40, the Challenger 1, the M1A1 Abrams and the EE-T2 Osorio tank. The EE-T2 Osorio was fitted with a French 120 mm smoothbore gun from GIAT and a fire control system developed by the British company Macroni. It included a 16 bit microcontroller and a SAGEM MVS 580 optic with integrated thermal imager for the commander (the same sight was later fitted to the Challenger 2E, which underwent trials in Greece). According to claims made by a Brazilian source, the Osorio was the only tank capable of hitting a stationary target in 4,000 metres distance. Against moving targets (at distances of 1,500, 2,000 and 2,500 metres), the Osorio supposedly hit eight with twelve shots. The Abrams hit 5 with twelve shots, while both of the other tanks managed to hit only a single target. The fuel consumption of the German engine was 200 g/kWh, which allowed it to travel a distance of 400 kilometres, further than any of the other three tanks. In 1992 the M1A2 Abrams and the Challenger 2 were tested in Kuwait. During the tests numerous results were leaked by American representatives in order to prove that the Challenger 2 was the worse tank. In a statement made to Jane's Defence Weekly, British sources suggested that General Dynamics didn't tell the whole truth. Both tanks failed to climb a 50% slope, because it consisted of loose sand and chalk. The Challenger 2 had to be towed after driving 80 km on flat ground. Maximum speed achieved by the British tank was 50 km/h, while the Abrams managed to reach 65 km/h. The brakes of the Challenger 2 worked too slow in the opinion of the Kuwaiti officials, needing between 50 to 70 metres to come to an halt. When trying to hit a T-55 tank at a distance of 4,000 metres, the M1A2 managed to hit one out of two shots (apparently it used APFSDS rounds); the Challenger 2 fired six HESH rounds at the same target, all missed. Firing at unarmored targets at distances smaller than 4,000 metres was easy for the Abrams. It hit 10 out of 10 targets, while the Challenger 2 hit only 7. Shooting on armored targets, the Challenger 2 hit four out of four shots, while the Abrams hit nine out of nine. General Dynamics' tank was also better at firing on the move; the Abrams hit three targets at a distance of 2,000 metres with three shots, while the Challenger 2 hit one out of three. In hunter-killer operations, the Abrams required 32 seconds to destroy four targets with fourt shoots; the Challenger 2 hit 3 targets out of four in 66 seconds. Accuracy when firing during night and fuel consumption had still to be measured, but Vickers believed to have an advantage there (at least in fuel consumption). http://btvt.info/1inservice/abrams_vs_chelly.htm Challenger 2 ARV towing an Abrams, which failed to climb a dune.

Do you have the full document from where these pictures a taken? If so, can you post it? This is very interesting and probably reflects the state of German armor development in 1973-1974, when the decision was made to improve armor protection. This lead to the T14 mod. turret (Leopard 2K turret that was modified with special armor). There is also a photo that was posted in an English book which shows a Leopard 2K prototype with add-on armor on the hull. Well, the mantlet is always a weak spot. But you are right, the slope is caused to provide maximum protection along a 30° arc. At 15° impact angle, the frontal armor will have a slope of 40° and an effective material thickness of 189 mm. The required protection was to stop a 105 mm APDS at 800 m distance. According to US documents, a 105 mm APDS penetrates 254 mm steel according at 1,500 m distance. But we were ignoring the fact that tanks are not designed with protection from the direct front only in the previous discussion, thus I don't really see a big difference. The Leopard 2 would also have less than ~430 mm protection when hit at an impact angle of 30°.

There were improved armor arrays being developed during the 1970s, which improved protection against both KE and HEAT compared to previous prototypes. The canceled Chobham-armor upgrade for the Chieftain tank also would have met the US requirements in many areas (and it had better side armor as demanded). The British tanks had a higher level of protection, because more weight was used for the armor. The Chieftain Mk 5/2 would have had a greater weight as the M1 Abrams, but was designed to feature a weight-efficient aluminium construction - that means a lot more weight could be used for armor. The MBT-80 was heavier than the Abrams, but was designed to use a hybrid construction (steel and aluminium), so again more weight could be used for armor. The Chieftain with similar construction technology as the Abrams weighed quite a few tons more - more weight was available for the armor. I think you might be misreading the graph. It shows the protection level in relation to the percentage of the surface area that achieves such a protection level. If you take a look at a photograph of a Leopard 2 taken from the front or at a scale drawing from the front and then take a look at the armored surface area excluding the tracks, you'll get 100% of the protected area. At 50% of this area, the very first production model of the Leopard 2 achieves a protection level equivalent to 300 mm steel armor or more against KE penetrators. Now given that the we know the armor thickness of the Leopard 2 - it has been measured, we know that at certain areas physically cannot reach a protection level of 300 mm or more against KE. We also know where the armor is thicker and thus most likely reaches more than 300 mm protection against KE. @Laviduce has done a lot of work on this topic, you can find it here and in the Leopard 2 thread. If you take a look at the turret front - where the Leopard 2 has the thickest armor - you'll see that it covers about 18% of the armored surface area. Reading the graph at 18% leads to a protection level of about ~430 mm steel-equivalent protection against KE rounds. I am not a big fan of repeating myself multiple times; this topic has been discussed excessively and sources have been posted here and in the Leopard 2 topic. The official reports from the Comptroller General and the congressional hearing on the Leopard 2AV testing pretty much say that the biggest reason for the Leopard 2AV being considered worse protected was the armor coverage: the late XM1 prototypes had 86% more surface area covered by special armor. The Leopard 2AV also had somewhat poor armor protection, because the hull was hastly redesigned to accept special armor and Germany never had designed a hull for this type of armor previously. Some officials from the United States suggested that it was a clever idea to incorporate fuel tanks into the frontal hull armor, thus the Leopard 2AV had reduced special armor volume in the hull and a rather inefficient frontal hull armor array (replacing the fuel tanks with composite armor allowed to reach an equal or higher level of protection at a much lower weight). The Comptroller General mentions that both the FRG and the United States weighed the protection of the perceived threats differently - given that the US Army valued protection against shaped charge warheads very high, that pretty much leaves only the optioon that Germany was more focused on protection against KE rounds. This is supported by the official protection requirements for the Leopard 2K including no protection against shaped charges (at a time when the United States were experimenting with various armor arrays to protect against shaped charge warheads) and the requirements for the Leopard 2(AV) - the Leopard 2(AV) was designed with protection against a 96 mm shaped charge (MILAN warhead) instead of a 127 mm warhead, but also against a tungsten-cored APFSDS round apparently fired from a high-pressure 105 mm smoothbore gun as fitted to the earliest ten Leopard 2(K) prototypes. The Leopard 2K already had more than 300 mm vs KE at the turret front when hit straight on. I.e. the turret front was formed by a 38 mm high-hardness steel and a 84 mm armor steel sloped at 25° - that's 280 mm steel along the line of sight, which due to the high-hardness frontplate and spaced configuration will provide a noteworthy boost in armor protection. Why do you think that the XM1 with three metric tons less weight, a greater frontal surface area, more armor weight & volume distributed to the flanks and with an overall physically larger size would have a higher level of KE protection? The UK chart is interessting, but reading too much in a single number alone doesn't make sense. The same document clearly states that the Leopard 2's armor protection was "imbalanced" and lists the effective hull armor thickness of the Leopard 1, T-62 and Centurion... "Imbalanced" could very well mean "imbalanced protection between hull and turret", which is something that can be found on the Leopard 2K and the Leopard 1 tanks with upgraded armor (Leopard 1A1A1, Leopard 1A2, Leopard 1A3). Going back to the graph leaked with the Swedish presentation and doing an analysis of the surface area of the Leopard 2 front - as done by Laviduce - leads to a hull armor protection of 280 - 340 mm vs KE on the hull; I'd call that reasonable close! It is also noteworthy that the Leopard 2 hull was still being redesigned and might have included little to no special armor (as in case with the Leopard 2AV) at that time. No, that is incorrect. The slide from Dipl.-Ing. Rolf Hilmes' presentation at the DPM does say Leopard 2A4, but it also lists the weight of the tank at 55.2 metric tons, which means that it refers to a Leopard 2A4 from the early production batches. The Leopard 2A4 was produced with three different armor packages: the original armor package was used on all Leopard 2A4 tanks produced between 1985 and 1988. This is identical to the armor package adopted on the first production variant ("Leopard 2A0") from 1979 (Germany did not pay attention to upgrading the armor until a 1986 program by the BWB). the second generation armor package (in C-technology) was adoped in the middle of the sixth production batch in 1988 and was kept for the seventh batch. the third generation armor package was adopted in 1991 and utilizes (D-technology). It was used on only a few tanks, all of which were later split-up, the hulls were used for the Leopard 2A5, while the turrets were mounted on some of the oldest hulls Why does this matter? Because beginning with the adoption of the second generation armor package the weight of the tank was raised from 55.2 metric tons to 56.5 metric tons. Hilmes' citing a weight of 55.2 metric tons hence means that he either mixed up data from different variants (which would be stupid) or that he refers to the original production batches of the Leopard 2A4. I think you posted a wrong link, because that is refering to an article on Andrei's website about Rheinmetall's 105 mm gun. Maybe you meant this graph from Krapke's 1986 book? This shows the KE protection of the turret armor of various German and Soviet tanks in relation to the armor penetration. As you can see, the Leopard 2 is meant to survive a 125 mm APFSDS at 1,500 m distance; the Brits estimated a penetration of 445 mm at 1,000 m distance for the Soviet tungsten-cored APFSDS in 1978 and 460 mm for the DU APFSDS round. That would fit nicely to a protection level of ~430 mm at the turret front. At this time the Soviets had adopted the 115 mm BM-28 APFSDS with a certified penetration of 380 mm at 2,000 m distance, which - if this or a similar estimation was used for the 115 mm APFSDS in the graphic - would again fit to a protection level of ~430 mm... Unfortunately I don't even think that this graph is very relevant, because it seems that the values are taken from the article "Panzerwaffen: Feuerkraft und Panzerung im Vergleich" published in the Swiss defence magazine "Allgemeine schweizerische Militärzeitschrift" in 1980. After finishing the Leopard 2 project, Paul-Werner Krapke retired and moved to Switzerland, where he worked on his book and published a number of articles in the very same magazine. While he did not publish this article, he might have fallen back to the values (or is it a coincidence that all of them match? I don't believe in this coincidence). The values are estimations according to the article. According to the article, the 115 mm APFSDS used as example is made of WHA (not steel with tungsten-carbide slug), has a length of 545 mm and a diameter of 48 mm. It can penetrate a NATO tripple heavy target at 2,000 m. I don't think such an APFSDS was ever accepted in Soviet service. I'm sorry, but that is just pure bollocks. Got any source for your impression? Because according to declassified documents available in the UK National Archives, Germany was the first choice as partner on tank and armor development for the UK. The FRG got access to the full Chobham armor technology three years before the United States (from the British perspective, the US was too much focused on Vietnam and therefore an unreliable partner for defending Europe). The UK and Germany started developing a common tank for both countries in 1972 (to replace the Chieftain and the Leopard 1), which was protected with a Chobham armor variant specifically optimized to meet the German requirements. This armor was known as Buckhorse armor. The co-development ended in 1977, because of different opinions on the conception (Germany didn't want to design a second Leopard 2, when they already were making the Leopard 2; the UK wanted a conventional tank like the Leopard 2). Based on the official data leaked by the Swedish trials, the Leopard 2-2A4 (1979-1987) had ~300 mm hull and ~430 mm turret armor protection against KE ammo, which matches with the other available sources and basic physics (more mass per area = better frontal armor protection). The Leopard 2 also made use of high-quality steel with ~380 BHN for the base sturcture, which lies above what is supposedly used on some other tanks (and specifically a lot better than the 270 BHN cast armor used on Soviet turrets). There is a Russian book which claims that according to a Soviet intelligence report from the 1970s, the "German Chobham" follows the same concept as the US variant, but uses a different sandwich structure: the illustrations of the Abrams' armor array show sandwich plates in a symmetrical configuration - front and rear plates of the sandwiches are rather thin. According to the Soviet report, "German Chobham" uses much thicker front plates (25 mm) made of high-hardness steel with very thin rear plates (3 mm). This would offer improved protection against APFSDS rounds (thinner steel plates like used on the Abrams are less efficient against APFSDS rods, while high-hardness steel improves protection), but would offer - at least per weight - less protection against shaped charges. When it comes to the Leopard 2(A0) and the M1 Abrams, I think the easiest way to see why the Leopard 2 should have a higher level of frontal protection is to take the following things into account: the Leopard 2 is physically smaller than the Abrams; it has a shorter hull, a shorter turret, a narrower turret and - if we exclude skirts - also a narrower hull. It has greater ground clearance, but is a bit taller. Overall the frontal profile is 10-15% smaller. the Leopard 2 focuses all its special armor on the frontal section; in case of the Abrams much more armor is used to protect the hull sides and turret bustle the physical armor thickness is greater on the Leopard 2 the armor of the Leopard 2 seems to be more focused on KE protection based on previous requirements and available sources The side skirts of both tanks manage to perfectly illustrate the design differences: the Leopard 2 has short but heavy ones, while the M1 Abrams has very thin ones, that cover a larger surface area. Edit: Also Hans Rühle is a troll, who will say everything to reach his goal of Germany producing his own nuclear weapons. Accepting DU would be a first step in his opinion.

No, Slovenia got you covered... https://www.shephardmedia.com/news/landwarfareintl/slovenia-weighs-boxer-mortar-variant/

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. 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). 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.

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

That's the turret from the "Ukranian BMPT"... must have thin armor, if it fits on a BMP hulll... http://www.armyrecognition.com/arms_and_security_2017_online_show_daily_news/strazh_new_ukrainian_bmpt_fire_support_vehicle_based_on_t-64_mbt.html

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. 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. 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: a distrupting stage to break KE pentrators and shaped chage jets a distrubing stage, which makes sure that the particles and fragments of the broken penetrator change direction and yaw angle 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. 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. 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. 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? 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! 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. 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.

I don't have a LinkedIn account. What does it say?

There was a diagram from the LS-Dyna simulation software on some T-90S advertising poster, which suggests that the general armor layout of the T-90S' welded turret is identical to the T-72B turret; however armor thickness and materials might be different. I'll try to find the picture. The T-84 also seems to utilize the same armor as the T-80U, but with improved materials (much higher quality steel) and increased overall thickness (1,200 mm instead of 700-800 mm). The T-72B doesn't use BDD though. PS: The welded turret is supposedly made out of electro-slug refined steel, which provides 15% more protection than cast steel at the same weight/thickness.

The Leopard 2A4M doesn't use AMAP from Rheinmetall/IBD, but a protection kit from KMW. A Leopard 2A4 with AMAP is said to achieve the same levle of frontal protection as a Leopard 2A7, that is not the case with the Leopard 2A4M CAN. Having less side armor makes it worse in this area; it depends on how the protection is valued. Spielberger probably based his statements on Swiss documents, which might have gone deeper into detail. The CV90 for example was considered better protected than the Marder M12 and the Warrior 2000, despite a similar level of armor protection, because the smaller size and location of the fuel tank were seen as superior by the Swiss military. In that sense the Leopard 2 could have equal armor at all places (which it doesn't have), but still would be seen as not equallly well protected due to the ammunition storage.

Apparently the frontal turret armor modules fitted to the Leopard 2A4M CAN are empty and consists of a single armor plate (might be NERA, but I don't see any of the bolts as usually found on the Leopard 2A5's frontal heavy NERA sandwich plates). The description of these photos claims that additional armor can be internally mounted, however there are no signs of attachment points for this. Leopard 2A5DK damaged by an IED in Afghanistan: As I previously wrote, he said "not equal", which doesn't mean that the frontal armor protecttion is lower; given that the Abrams has more side armor (more area is covered by the heavy side skirt modules and the turret bustle is fitted with thick composite armor), the quote from Spielberger doesn't need to have any relation to frontal armor protection. I don't see this quote disagreeing with what I wrote earlier. The documents in the Swiss archives are not available to the public yet, see the column "Zugänglichkeit gemäss BGA: In Schutzfrist". However the titles of the document also confirm that the AMX-32, Merkava and the Challenger 1 were considered as optiopns at one point of time.

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

What are you exactly looking for? The T-72 protection requirements are taken from Zaloga and a Russian website. 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. Well, there are reasons for this... Turret side armor of the Ariete seems to be comparable to the Leopard 1A3... 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. 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.