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SH_MM last won the day on March 10

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  1. General AFV Thread

    M1 Abrams' TUSK belly plate is made of spaced aluminium plates and mainly works thanks to its massive thickness, reducing ground clearance by up to 11.5 inches (292 mm). AFAIK there is no other material, at least a photo of the belly plate in the TB 9-2350-264-12&P-1 shows no other materials. The Leopard 2A6M, Boxer, Puma and other German AFVs use mine protection kits from RUAG, which are made of composite plates. The outermost layer is a steel plate, but it also includes on or more layers of plastic fibre to absorb the energy. In case of the Leopard 2A6M, the belly plate reduces ground clearance only by 50-100 mm, but is supposed to provide the same level of protection as the TUSK's much thicker spaced aluminium solution... however the Leopard 2A6M's plate is heavier. In case of the Puma IFV, the mine protection consists of two sandwich plates with more than 100 mm empty space between them. RUAG's mine protection system. In theory it might also include ceramic materials against EFP mines, at least IBD Deisenroth is offering this as part of its AMAP-M anti-mine armor.
  2. Contemporary Western Tank Rumble!

    The British had some odd ideas about main battle tanks, although they wanted their MBT-80 to be more advanced in some aspects than the Challenger 2 currently operated by the British army... The lack of an indendepent sight for the commander was disliked The laser rangefinder of the M1 Abrams was incompatible with the thermal imager (?) For some reason the British military thought it was a bad idea to integrate daysight and thermal imager into a unitary optic The M1's fire control system resulted in a low hit probability (confirmed by statemens from US and German sources regarding the comparative trials of XM1 & Leopard 2AV) The armor of the M1 Abrams could be penetrated at ranges of 4,000 m by the 125 mm gun according to British estimates Storing ammo below the turret ring is/was seen as better than having a separated ammunition compartment at the rear of the turret because some US test proved that it might not always work with 105 mm ammo and wasn't tested with 120 mm; also the blast door needs to be open for reloading (silly complaint) Leopard 2's protection was "imbalanced" (sounds like the same complaint of the US military - too little side armor) and insufficient to stop a 125 mm APFSDS round (est. penetration 445 to 460 mm steel at 1,000 m according to the document) Shir 2 (that became the Challenger 1) was too heavy and also underpowered British believed it was impossible to modify XM1 Abrams' armor to stop 125 mm APFSDS ammo The drawing is from a 1975 patent by Krauss-Maffei. At this time the Leopard 2AV was being designeed. The patent topic are different ways to mount special armor in a main battle tank in order to allow replacing damaged armor modules, allow easier upgrading and allowing to completely remove the armor modules (which Krauss-Maffei suggested for traveling during peace time). The patent suggest three ways of mounting armor: mounting armor plates using screws (as done on the M1 Abrams) using armor elements that fit into a cavity and together (like the Z-shaped ones) without any sort of additional attachment putting the armor elements into "cages" or "boxes" with rubber-lined edges. The rubber-lined "cages" then are inserted with pressure into the cavities The patent menions that the Z-shaped layout would provide most protection but also requires most space. It is not mentioned what the armor elements are made of (only that they ideally use metal to allow easier mounting). As far as I understand all these drawings are placeholders and do not represent actual tanks or actual armor arrays. We know that all fully-assembled Leopard 2AV prototypes in the United States did not include special armor, only weight demonstrators. The special armor was send as armor modules for ballistic testing, which were only connected to a mock-up hull and turret. If they had already decided how this special armor would be mounted or not is unknown to me. IMO the most likely variant is the upper one (Fig. 7 and Fig. 8), i.e. the armor is mounted in boxes or cages. This would explain the box-shaped turret, makes replacing armor easier and fits to the drawings from Sweden. However I think that the actual armor might look closer to the Z-shaped arrangement form Fig. 5 (there is no reason why it should be impossible to mount the Z-shaped armor elements at different angles in a cage/box). The method using bolts seems to be the least likely, because the bolts would be visible from the outside, but only the smaller bolts holding the cover plate are visible on the Leopard 2AV and early batch Leopard 2 tanks - if the bolts were used, the coverplate would look like this:
  3. Contemporary Western Tank Rumble!

    So we don't really know if these values are actually representing the Leopard 2's turret armor or are from some other file (camera instruction manual)? If these protection values would be representing the actual Leopard 2 and if these were actually based on tests with the 120 mm DM33/JM33 ammunition, then it most likely would mean that the Leopard 2 would reach a (slightly) higher protection level against older types of APFSDS ammunition. The 120 mm DM33 APFSDS was specifically optimized to defeat multi-layered armor, against which older designs of APFSDS were found to be rather insufficient. According to a patent from Rheinmetall, a special tip design developed in the mid-1980s allows to increase the penetration against multi-layered armor, specifically such armor designs with "bouncy"/elastically mounted steel plates. The NERA arrays used on the Leopard 2 could be described as such armor - the German text speaks of "komplizierten Mehrschichtpanzerungen" ("complicated multi-layered armor arrays") and "federnd aufgehängten Panzerplatten" ("resiliently mounted armor plates"). The moving metal plate(s) of a NERA sandwich can be described as "Federblech" or "Beulblech" in German, with the armor of the Leopard 2 being called "Beulblechpanzerung" (bulging-plates armor) and "Lamellenpanzerung" (the latter term is used by the Austrian Bundesheer). According to conservative estimations during the development of this new tip design, the penetration performance of the APFSDS ammunition could be increased by more than 10% against certain special armor arrays. So a measured protection value of 380 mm RHAe - if this reflected the Leopard 2's claimed protection against the 120 mm DM33 APFSDS - could very well be 400-440 mm steel-eqivalent protection against older rounds such as 120 mm DM23, Zakolka, Vant, Mango, etc. However I don't think it is very likely, that the 120 mm DM33 ammunition was used for the data delivered to Japan. The 120 mm DM33 entered service in 1987 with the West-German Bundeswehr, which would be the last stage of the Type 90 development. I suppose the performance data of the Leopard 2 tank was requested before spending several million USD (or an equivalent sum of Yen) on the development of a new tank. Do you know when the data for the Leopard 2 was requested by Japan?
  4. Contemporary Western Tank Rumble!

    You can see the armor thickness in the photo above. This is the Challenger 2 tank located at the Bovington Tank Museum. Does it specify how the armor protection was measured? I.e. what type of ammunition was used to establish the protection level? Is this the minimum/average/maximum protection along the frontal arc or when direclty hit at the front? Is the value "50%" related to this (e.g. is this the protection achieved on 50% of the tank's surface)? The Swedish documents suggest that the Leopard 2 with the original armor package has at least 300 mm steel equivalent protection vs KE at ~63% of its surface, at least 340 mm steel equivalent protection vs KE at 50% and at least 400 mm steel equivalent protection vs KE at 20% of the surface. The Japanese data seems to confirm this, but there still should be some places with at least 400 mm vs KE.
  5. AFV Engines

    No, it wasn't an argument about the suspension. The article published in the ARMOR magazine talked about the available net horsepower at the drive sprockets - so the suspension and cross-country are not part of the equation. I.e. Richard M. Ogorkiewicz wrote in "Technology on Tanks" (published in 1991) that "in general" only up to 70% of the actual engine output are available at the drive sprockets. The author of the article in the ARMOR magazine cites this statement and claims that the Merkava 3's powerpack has a 71% efficiency, implying (because the statement referencing R. M. Ogorkiewicz said "not more than 70%") that the performance delta between the other tanks with 1,500 hp engines is smaller than the actual difference in engine output. This is followed by a vague statement about "tanks powered by 1,500 hp engines" not performing better; the author failed to clarify if he meant in regards to efficiency, absolute net horsepower available or in regards to cross-country performance.
  6. Contemporary Western Tank Rumble!

    The Challenger 1 is based on the Shir Iran 2 main battle tank designed for Persia. According to British data, the Shir (Iran) 2 prototype's armor offered protection comparable to only 325 mm steel at the frontal arc. The British military desired a higher level of protection, but it is questionable how much better the actual production version was. If you look at the power to weight ratio of the Shir 2, you'll notice that it should weigh about 63-65 metric tons - like the Chieftain-based Shir (Iran) 1, the second version was also fitted with the Condor Perkins V12 engine developing 1,200 hp. There is quite some time between the date of the document (1978) and the introduction of the Challenger 1, so they could have adopted a new generation of Burlington armor or at least chosen to integrate another variant, which was more optimized against KE. However I think your "620 mm RHAe for a LOS thickness of up to 850 mm" is a rather far stretch: the desired protection for the MBT-80 was to resist 125 mm APFSDS at distance along the frontal arc (est. penetration 445 to 460 mm at that range). The table lists the MBT-80 with a protection level of 430(+) mm. I think this should give us a ballpark estimate for armor protection. Please note that the MBT-80 was expected to achieve such a high level of protection thanks to the usage of aluminium armor for the rear section of the vehicle, an idea that the British FVRDE was very fond of, as various other projects show (older projects such as the Chieftain Mk 5/2, FV 4211, JagdChieftain, and Vickers Valiant used full hulls/turrets made of aluminium). The Chieftain is a very heavy tank for its day, so one should expect a high level of protection; but it is also very large with a rather heavy gun. The British themselves claimed that the M1A1 HA has better protectiton at the frontal turret arc than the Challenger 2 prototype design from 1988, which was supposed to offer improved protection over the Challenger 1. I don't know where you are getting the values for the armor thickness and protection of the M1 Abrams and M1A1/M1A2 model. I know that there are a lot of different armor thickness values floating around, but none of them are confirmed. These are either "guesstimates" or based on scale measurements done on drawings. These are not very accurate. I remember a discussion with Damian back on DFI, where he claimed the M1A2 has 960 mm thick armor. Measuring the drawing from Hunnicutt's "Abrams: A History of the American Main Battle Tank" which he provided, resulted in an armor thickness of less than 800 mm. He then added his own lines where the armor modules would end, because the sketches in Hunnicutt's book are rather inaccurate (I agree with this - the weldlines do not represent the actual armor). However based on his new lines (which IMO extended a bit too much into the tank) the armor thickness would have been 820-840 mm on the left and 880-900 mm on the right side (depending on wether the pixels of the lines were included or not). Then another poster joined the dicussion, who had created a 3D model of the M1A2 Abrams. He came to the conclusion, that both front modules of the turret were only 845 mm thick, but the backplate extended even further into the turret than on the altered drawings from Hunnicutt... Over the years I've seen thickness values for the Leopard 2A4 ranging from 500 to 900 mm (we've gotten a confirmation that it's ~860 mm), from 600 to 800 mm for the M1 Abrams and from 750 to 1,000 mm for the M1A2... given that range I'd be rather careful to base armor protection estimates on "guesstimated" thickness values. Aside of statements from Zaloga, I've yet to see actual proof that the physical thickness on the M1IP/M1A1 was increased over the M1 Abrams. I don't know where you got the 440 mm RHAe vs KE for the M1 Abrams. The CIA document from 1982 revealed that "one version" (which we just assume that it is the basic model - in theory it could have been the design for the M1IP/M1A1: the M1E1 prototypes with weight demonstrators to resemble the armor package then in the making were delivered in March 1981) had 400 mm RHAe vs KE at the turret; there is no statement made regarding wether this protection is achieved along the frontal arc or this is just achieved when the turret is directly hit from the front. In theory both the British and the CIA estimates could fit together, with the turret achieving 340 mm steel-equivalent protection when hit at a 20-25° angle (nullifying the slope along the horizontal axis) and 400 mm steel-equivalent protection when hit directly from the front. Given that composite armor elements such as NERA panels, STEF, glass and ceramic tiles provide different protection at different angles, it could very well be that the efficiency increases with at larger impact angles (and thus lowered thickness) to provide a more consistent level of protection. For the M1A1, I think we can use the M1 Abrams' armor protection as a basis and use the weight simulators of the M1E1 as a reference how much armor weight was added. Given an anti-KE mass efficiency of 1 to 1.5 (based on British documents on the development of Chobham), the M1A1's armor protection could be estimated. The export M1A2 has 600 mm vs KE for the turret armor along the frontal arc. If we assume that the armor efficiency stays the same regardless of angle, that would be 640 to 660 mm from the front (depending on which side of the turret front is hit due to their different angles). As for your model of the Leopard 2: I don't think it is very accurate. According to the Swedish documents, last slide, about 20% of the Leopard 2's frontal projection reach 400 mm RHAe vs KE or higher; in your drawing it is roughly 17% of the turret only. Given that the hull has a similar surface area, I think you should at least double the area with 400+ mm steel-equivalent protection vs KE. But due to the fact that the protection provided by composite armor depends on the specfici interaction between armor array and penetrator, I personally wouldn't want to use singular values for armor protection. Early Soviet APFSDS ammo (and some NATO types like M735) was really, really bad at defeating everything other than a simple steel plate. The DM13 was specifically optimized to defeat multiple spaced steel plates, because the earlier APFSDS ammo designs (used for the M735 and the MBT-70's APFSDS ammo) couldn't do that. The above is a composition from various sources, so I wouldn't rate that reliable. First of all the drawing used by Hilmes didn't include a backplate (it was censored), so the line drawn in the photo is not really accurate. IRL the thickness of the center plate is parallel to the outer plate - it only gets thinner at the top (where the slope is increased to provide sufficient protection against older types of ammo) and at the lower section (where the tank is less likely hit). The image section showing the turret is from a patent regarding a new recoil mechanism, which would sit within the left and right corner of the turret, rather than on the gun. This would require redesigning the complete turret, so I wouldn't necessarily consider that a reliable source. There are also patent drawings showing a cicrcular hole in the armor for the EMES-15, we know that this is not true.
  7. AFV Engines

    It might be the same type of logic used to defend the Merkava 3's 1,200 HP engine compared to the 1,500 HP AGT-1500C: the transmission is more efficient than the previous model, so that it can deliver more performance out of the 675 HP engine to the drive sprockets than the old transmission could extract out of a 800 HP engine. I.e. the old transmission would loose something like 150 HP out of 800 (thus effectively having 650 HP at the drive sprockets), while the new transmission would only loose 25 HP. The same argument was being made by some IDF soldier in the ARMOR magazine quite a while ago - i.e. the Merkava 3's 1,200 HP would come a lot closer to the AGT-1500C due to the higher efficiency of the Renk 304S tansmission. Given that Hunnicutt claims that there are 1,232 net horsepower available in case of the Abrams', this statement was probably exaggerated.
  8. General AFV Thread

    I think this is a rather optimistic colorization on the model. If the documents from Sweden have shown anything, then it should be that achieving a consistent level of armor protection is nigh impossible. The red area on the hull extends to the floor plate - there shouldn't be any composite armor at all. Furthermore the upper edge of the armor modules likely (due to the reduced thickness along the line of sight) won't achieve the same level of protection - that's at least the case in the Swedish computer analysis of the different turrets. The gun mantlet armor module is very thin, so I'm not sure if this should be able to achieve the same protection level as the turret armor (even at 30° impact angle the turret will be thicker. Defeating the JM33/DM33 APFSDS at 250 metres requires just 530 mm of armor steel or a special armor array providing equivalent protection. The Leopard 2A4 production model from 1991 supposedly has armor providing about 550 mm steel-equivalent protection at 50% of the tanks surface along the frontal aspect. The Type 90 being designed at the same time (being lighter, but also significantly smaller) achieving a similar level of protection to the contemporary Leopard 2 variant seems plausible.
  9. Contemporary Western Tank Rumble!

    I've been wondering about the protection difference between the Swedish version and the German version. What I found very odd is the table on the last slide I originally posted, which list the Leopard 2 Improved with Vorsatzmodule of the generation "D-2" and internal armor of the generation "B". I think this might be a reference to which prototype was send to Sweden for tests. The original Leopard 2 Improved prototype was the Komponentenversuchsträger (Leopard 2 KVT; "component test bed"), which was based on the chassis number 20825 (the 825th tank made by Maschinenbau Kiel). Based on this number, it appears that the hull (and turret) were made as part of the 6th Leopard 2 batch (the second batch of 2A4 tanks) made between January of 1988 and May of 1989. The previous batch (batch number 5, first batch of Leopard 2A4 tanks) was produced between December of 1985 and March of 1987, while the last batch of Leopard 2A3 tanks ended with the chassis number 20644 for MaK. Given that 45% of all German Leopard 2s were made by MaK and the 5th batch consisted of 370 tanks; therefore I assume that the 5th batch ended with the chassis number 20810 or 20811. The first 96 tanks of the sixth batch were made with the old armor, therefore the chassis number 20825 would fall into that category. The later Leopard 2 Improved prototypes (Truppenversuchsmuster Maximum and Truppenversuchsmuster Minimum, "troops trial model maximum/minimum") were based on the chassis numbers 11156 (TVM max) and 11157, which were made by Krauss-Maffei and belonged to the 8th batch (the last batch of tanks for the German Army) made between January of 1991 and March of 1992. This would mean that original KVT (later renamed IVT) used 1st generation composite armor (also confirming that the "B" in the table stands for the original composite armor), while the TVM tanks had 3rd generation armor (believed to be "D-1", "D-2" or "D-3" in the table). The actual Leopard 2A5 and Leopard 2A6 tanks were made using hulls from the 6th, 7th and 8th batches - so all German tanks with the second and the third generation of composite armor + 22 tanks with the original hull armor package. If the hull armor wasn't altered (although I assume it was), this would mean that there would be some tanks with worse/better hull armor than the others... The turrets were all taken from the 1st batch, so they probably replaced the armor inserts and upgraded them to "C" or "D-1/2/3" level. According to the book by Scheibert, the armor modules in the turret were replaced. According to one issue of the Waffen-Arsenal magazine ("Leopard 2 A5 - Euro-Leopard 2" by Michael Scheibert), the Leopard 2 tested in Sweden was either a KVT/TVM mix or they tested both variants (not written clear enough for me to understand what was the case). In theory this might mean, that the higher level of protection of the Swedish variant is just the result of using "C" or "D-1/2/3" level armor inserts with the same Vorsatzmodul. Yes, that's true. However I've never seen a cast turret with composite armor in the gun mask and Soviet gun masks tended to be thinner. Also the composite filler of the turret always ends a few centimetres away from the gun mount.
  10. Contemporary Western Tank Rumble!

    It depends on which armor package the Norwegian Leopard 2A4s are fitted with; the armor packages from 1987 and 1992 (or at least this is what I think the graph shows) would still be able to withstand older Soviet/Russian APFSDS ammo at long ranges. Don't forget that the majority of the Russian tanks seems to rely on Vant and Mango. Only the newer vehicles (T-90, T-90A and Sprut-SD) and upgrades (like the T-72B3) can utilize higher penetration APFSDS. So its still "good enough" to deal with the majority of the older tanks and IFVs. Now that the BMP-2 will receive Kornet and the T-72B3 is being adopted in larger numbers, it is time to upgrade. If the CV90 -120T is not fitted with an active protectiton system, then it is not really better than the Leopard 2A4. It is a larger target (higher hull and turret, wider hull), while probably providing similar mobility and less protectiton. Only the lighter weight and the more advanced FCS make it superior. Buying an armor package (AMAP) and adding new electronics seems to be a much better idea IMO. That the Leclerc wasn't well armored is no surprise, given its state of development (being pretty much a prototype during the tests) and its turret layout. I have mentioned the weak gun mantlet and the "gun bulge" in the turret roof several times, see the very first post of this topic. When seeing the tank from the front, it will have a lower profile, but not from the side. At the 20° angle, the Leclerc needs to protect 1.7 m² (for a crew of 2), while the Leopard 2 needs to protect only 1.6 m² (with a crew of 3!). That's quite surprising IMO. The later Leclercs feature thicker and heavier armor packages, so they probably closed the gap... (from the Steel Beasts forum): They also added an armor block at the gunner's sight (left - old prototye, at the right is a newer model): ___ Forgot to make a screenshot of the T-80U's armor, but Andrei_bt already made one: That's the doownside of cast turrets with ERA... PS: Also confirms DM33 penetration to be 470 mm at 2,000 m distance, 540 mm at 200 m distance.
  11. Contemporary Western Tank Rumble!

    Wow,. thank you @skylancer-3441. Seems like R. Lindström (accidentally?) uploaded some (formerly?) claissified documents in his original presentation. That confirms that the diagram is real, @Militarysta M1A2 turret was also meant to receive add-on armor... Leclerc armor was very poor: Leopard 2 armor evolution: Turret front of a Leopard 2A5 is about 700-800 mm vs KE, 1,600 to 1,800 mm vs HEAT. The Swedish Strv 122 has a different armor package, providing higher protection levels; the Leopard 2 (flat turret) has 300 - 500 mm vs KE protection, but about 50% of the surface is protected against APFSDS ammo with less than 400 mm penetration into steel only. Note the last slide: The German prototype offered to Sweden (and maybe also the German tanks) have Pakete (integrated armor pacakges) of the technology generation "B", while the Vors. Modul (Vorsatzmodul, add-on module in front of the armor) has the technology generation "D-2". I suppose Sweden uses a more modern integrated armor pacakge (C, D-1, D-2, D-3) and the same Vorsatzmodul. The German wikipedia (without citing a reference) claims that the German Leopard 2 uses "C technology" armor (so "Pakete"). Maybe that's based on Spielberger's book, I need to take a look at it in the future. The graph in the center of the last slide shows five colors... my guess (based on the graphs at the left and the right: purple - Leopard 2 from 1979, armor package of the "b" generation (fits the graph on the left); red - Leopard 2 with enhance armor package (1987), which might be "C" generation; yellow - Leopard 2 with enhanced armor package (1992), which might be "D-1" generation; blue - Leopard 2 with armor of the "D-2" generation or armor of the "B" generation with Vorsatzmodul of the "D-2" generation green - Leopard 2 with armor as adopted by Sweden - so probably "C" or "D-1/2/3" base armor with Vorsatzmodul of "D-2" generation This would lead to the following protection estimates (please note that it says frontal arc - +30° to -30°, not direct from front): Leopard 2 - 2A4 (from 1979): 300 mm protection vs KE at 60% of the surface, 400 mm protection vs KE at 25% of the surface Leopard 2A4 (from 1987): 300 mm protection vs KE at 65% of the surface, 400 mm protection vs KE at 55% of the surface, 500 mm protection vs KE at 30% of the surface Leopard 2A4 (from 1992): 350 mm protection vs KE at 93% of the surface, 400 mm protection vs KE at 87% of the surface, 525 mm vs KE at 50% of the surface and 620 mm vs KE at 42% of the surface Leopard 2A5 (prototype?): 620 mm protection vs KE at 65% of the surface, 700 mm protection vs KE at 40% of the surface Leopard 2A5 (production model? Swedish model?): 700 mm protection vs KE at 75% of the surface That also confirms that the older Leopard 2 models didn't feature the enhanced side armor found on newer production variants: Btw: "gor" seems to be pentrated, "ub" means to be not penetrated in one of the earlier tables.
  12. Contemporary Western Tank Rumble!

    Are you sure? Is it confirmed to be fake? This is from a presentation by R. Lindström, who works/worked for the Swedish FMV: Except for the values, everything is there (lower left corner). The same set of presentations includes a lot of 100% valid files: So overall the drawing seems to be valid. Maybe the guy photoshopped the drawing into the background of a FMV file and added his own values - but look at the drawing in the left corner of the first slide: this drawing does exist and it does have oddly placed text... maybe because R. Lindström wasn't allowed to post the true version (which would have protection values there?)...
  13. Contemporary Western Tank Rumble!

    No, only at the turret front. The volume is a limiting factor, if you want protection against large calibre KE rounds and tandem shaped charges. Just look at the Leclerc (armor thickness increased on later variants), T-84 (armor thickness increased compared to T-80UD) and Leopard 2A5/Evolution/ADT/MLU (all adopting external armor modules, because the frontal armor doesn't have enough volume).
  14. Contemporary Western Tank Rumble!

    Here are two quotes from Rickard's O. Lindström's article on the development of the Strv 2000, which might be relevant to the protection level of NATO tanks in the 1990s: The above statement is made regarding the development of the Soviet 125 mm APFSDS ammo: NATO tanks of the 1980s doesn't seem to be protected against the weapons/ammo used by Warsaw Pact tanks. This probably meant that the protection of the tanks tested in Sweden wasn't necessarily as high as usually estimated on the internet... Inspired by the M1A1 HA, the Swedes tested DU as possible armor material for the Strv 2000 tank project. It showed that the usage of DU increased protection, but only if the volume was the limiting factor. If the weight was the limit, other materials could reach similar (or higher) protection.
  15. Tanks guns and ammunition.

    Is this the M829 APFSDS? (upper target is titanium, lower one steel).