Scav

@LoooSeR Footholes to climb up the tank? What are those holes above it?

What I find odd is how the KVT was based of a 5th batch vehicle and thus had B tech internal armour, but the TVMs were based off 8th batch vehicles yet also had B tech internal armour according to that one slide..... How ecactly did they "discover" that the leopard 2s protection wasn't as good as other tanks? If this comes from the Brits, I think that might be due to them misinterpretting the slides and info given to them (or their higher requirement for CE). ^if this is the info they got or used to determine the protection, it lines up pretty well with the 50% area covered mark of this: For B tech it's about 330mm protection at the 50% mark, within margin of error and the 420mm for C tech is pretty much right on 50% area covered. Obviously using this as a measure for how well protected a tank is, isn't the best. Not to mention the reference threat could be substantially different. We also have to remember that the UK didn't like highly sloped armour plates, hence why they didn't use it on their tank (resulting in higher weight with worse armour protection on CR1), resulting in fairly large areas that could be considered "poorly protected" by the UK. What's the "cheaper option"? Using older hulls.....? That already looks like the cheap option to me.

I'm talking specifically about the ones they tested on Chieftain Mk5/2, Shir 2 and their proposals for MBT-80. The later versions that were optimised against KE quite significantly dropped in CE protection, MBT-80 specifically was originally required to protect against 430mm KE and 580mm CE, but they changed this requirement to 405mm KE and 850mm CE later on. It's important to note that Chobham was mostly tested against APDS and not APFSDS. Regarding the inclusion of a backplate, this was mostly done on the frontal armour where it would be easy to install the composite ontop of existing armour plates or make it easier to integrate, for the sides the backplate was often dropped due to different requirement (side composite was mostly for RPGs and light autocannons, don't need backplates for that) and simply not being practical.... They already found that splitting the skirts up into 18 different sections would make them impractical to handle and install by the crew alone, so they went with larger 4 section skirts instead, but that would still not make it practical to include a thick backplate as it would make the tank even wider an substantially heavier. Taking that into account, I think the backplate is a somewhat decent indicator to the internal armour array, if there isn't a thick backplate, it means the inserts themselves are considered good enough for KE or that it's simply impractical/not needed to have a thick backlayer. Then you can see where the armour is located, what the expected threats would be and make an educated guess as to what the internal array most probably looks like (in very basic terms). The exterior doesn't look that similar though, CR1/M1 = lots of angles leo 2 = more vertical, less angles. Unless the armour on the inside is angled, NERA like on CR1/M1 would be substantially less effective in a leo 2 turret as you know. Yes, but that doesn't mean moving steel plates can't increase CE protection, there's ways to move those plates apart from having them sandwich a rubber liner. Systems like the B&V add-on is what I'm referring to. Yes, and it seems they (UK) kept this design and refined it by adding plastics or rubber to the rear of the steel plates. Yeah, they use this for the side hull, didn't seem optimal for the front hull apparently. Never seen much info at all on the Kampfpanzer 3, most books just mention it in passing so it doesn't appear that important. Seems I wasn't clear: what I meant with moving plates is armour similar to the B&V add-on or the Marder 1A3, they're all shock absorbing or are "encapsulated" in plastic/rubber with a thin layer. When comparing the additional armour of the Marder 1A3 and Warrior for instance, they're completely different, the latter featuring skirts that are essentially thin boxes with thin angled plates on the inside (probably with a much bigger rubber plate attached to each steel one). Not saying leopard 2 doesn't feature NERA, just not the kind as seen in the Mk5/2 program, but they definitely thought differently than both the US and UK, otherwise they would've come up with a similar MBT design and the US wouldn't have commented that the 2AV had "inferior" armour. 2AV didn't have the composite skirts of the XM-1, later on they adopted the heavy ballistic skirts though they don't look like those found on M1 as they cover less area but are thicker. Similarly, the turret bustle only features spaced armour sufficient to protect against autocannons, not thick composite as found on M1. Basically, everything indicates they were more concerned with frontal KE protection, in which case medium thickness, spaced steel armour layers make more sense than the design as featured on Mk5/2. Only for two layer spaced armour though, with multiple layers this isn't the case, as seen on the Russian T-series that went for more, medium thickness steel plates with small airgaps or textolite Sure, if you don't have very much steel and space between the first and last layer, a thick plate makes sense, otherwise it seems better to more evenly distribute the same steel thickness over a larger space. Brits used it as their NERA sandwiches in comparison didn't contain much steel (as proposed on Mk5/2). It was an oversimplified representation, it doesn't have to be exactly like that. I was trying to point out the general layout and difference in steel/rubber concentration. 30-45mm thick, making sure autocannons simply don't affect the internal armour plates as that might require replacing them, which could be more expensive than replacing the outer plate. There's a variety of reasons why you wouldn't want autocannons to impact the internal armour, it might consist of very high hardness steel, have attachment points throughout which can be damaged, increased efficiency against LRPs..... The Russians do it, and they used armour arrays that wouldn't be affected much if at all by autocannons penetrating the first layer. It seems a first layer of 1-2 penetrator diameters is optimal against LRPs, even more reason to make the first layer between 30-60mm. Yes, I agree. This would indicate the individual layers are thicker and heavier on leopard 2 as opposed to M1, I personally think this is due to there being more steel and less rubber/plastics. Also, those mounting systems could just be for the entire array, not the individual sections. Having the individual sections a little bit smaller and with some kind of shock absorbing system between them, could definitely help (although not nearly as much as traditional NERA would, as you pointed out). Yes, though it's not unreasonable to think increasing the amount of plates and overal thickness of the array could make it work quite well against APFSDS, especially early ones. This can still be achieved by relatively simple spaced armour with multiple layers. I keep hearing about ceramics, but never saw any conclusive proof of their use in western MBTs (I'm also excluding Kvarts or similar fillers) and according to Lindstöm the Swedes tested several ceramics and found them quite lacklustre. Authors like to bring it up.... but apart from that.... As you say yourself, large difference of medium caliber APFSDS and HEAT rounds is the primary reason. Still, one to one is quite different from the ratios seen in US/UK Chobham armour schemes, those usually feature less steel comparatively (on the M1 the layers are also quite thin). But it shows that even for their more CE focussed armour designs, they feature relatively thick steel layers (all in comparison with M1/CR1), indicating that internal armour (which is quite likely to be mounted vertically) is less effective against CE and more effective against KE. Dunno, I think hull front + full sides + turret front and sides is even larger area than the add-on for the Marder which is mainly on the front hull and upper side hull (also on the turret, though it's relatively small), and the add-on for the Mk5/2 is substantially thicker.... You actually found info on those? Also, I assume that's just for the turret, I don't see any side hull armour. So, for KE it can protect against a 125mm APFSDS round at 1500m but only an RPG-7 for CE, nothing more? (granted it's still quite good protection) Again, I don't see why multi layer spaced armour wouldn't work against APFSDS, it works for the Russians, why not upscale their other AFV armour designs? Yes, this leads me to believe NERA as used on M1 or CR1 wouldn't be chosen, it focusses too much on CE. They didn't have a CE requirement for Bradley, wouldn't make sense to fit it with NERA, and DU would've been completely off the table anyway. Wasn't Stryker fitted with MEXAS of some type, to protect against 14.5s? That's quite different from 30mm autocannons. As for Warrior, yeah, and Leopard 2 didn't have that much of a CE requirement either (atleast compared to M1 or CR1). Especially if we assume that it's KE protection is around 430mm and CE is around 600-650mm, that's a very different ratio than M1 or CR1 (both around 2:1 CE to KE). Only used two spaced layers though, with more you can use thinner layers and more space, both were prototypes too. Leopard 1A3 used 12-68mm, mostly around 30mm. If you have more space and weight to play with, dividing thicker plates into thinner ones (up to a point) is quite smart and more mass efficient, Russians came to the same conclusion and went from 60-105-50 to 50-35-50-35-50 or 60-15-15-15-15-15-15-15-50. Having plates around 1-2x the penetrator diameter in thickness seems to offer an increase in mass efficiency compared to thinner plates and thicker plates don't seem to offer much increase past that. It took the Russians until the T-72B to use it in turrets, and until T-90 for the hull. In both instances, they used it as little as possible or with a much higher steel to rubber ratio. All of those instances they used the NERA sandwiches in high angles and shaped their armour appropriately, while internally angled plates are possible, it seems unlikely they'd be very angled on leo 2 according to some of those patents you've posted in the past. So, either the armour isn't mounted like in those patents and is quite angled on the inside (which would increase CE protection, probably beyond what leopard 2 had as requirement) or they used an other, less effective method to increase CE protection while keeping KE relatively high. Shir 2, which pretty much was minimally changed, was adopted as CR1 and had substantially lower protection than some of those documents claimed. Atleast one document talks specifically about Shir 2 and gives it 325mm KE protection on the hull (what round we don't know), other documents comparing XM-1, leo 2, Shir 2 and MBT-80 say that Shir 2 doesn't reach protection requirement (which was still 430mm KE at this point) and is too slow. The document that gives CR1 500mm RHAe is a rather dubious one at best, the first page of which says Challenger I can only protect against a T-72 tank round at 1000m on the front of the turret..... (said round was given 480mm of penetration at 1km). Newer documents that have surfaced specifically mention 105 and 120mm APDS being defeated and also some quoted russian round (probably the one from before), but the way it's worded indicates that only APFSDS rounds like the quoted russian round can be defeated. The Brits have previously shown that they consider Russian APFSDS to be rather poor or inferior to their own. Meaning that protecting against 125mm WP APFSDS =/= protecting against 120mm NATO APFSDS. That new doc also says it can defeat 125-150mm HEAT warheads, same as Mk5/2 (those were rated at 711mm of penetration), so only 700mm against CE seems rather low. Especially if we take into consideration that newer HEAT warhead manufacturing led to higher penetration with same diameter warheads. Frankly, CR1's armour doesn't seem to have changed from Shir 2, which wouldn't have very impressive KE protection against LRPs (better than M1 is likely though). The MBT-80 was considered to have superior protection and was a much more ambitious design, when it failed, I doubt that they somehow managed to put better armour than MBT-80 was intended to have, on the CR1 (which had the same armour thickness as Shir 2 mind you). That doc which claims 500mm KE also claims the hull was upgraded on "Challenger II" to 500mm, yet on Mk2 challenger the hull was the same thickness as before (~660mm LOS) and most definitely wouldn't reach such high numbers. Furthermore, that document has a lot of weirdness about it: Somehow, between a FES (fully exposed stationary) "Challenger II" at 500m and 1000m, there's a 1.2% higher chance to kill at the longer range? Despite said tank supposedly having 500mm KE on both hull and turret? Even at 2000m there's a 50% chance to kill a "Challenger II" that has 500mm KE on hull and turret with a round that only penetrates 480mm at 1000m...... Let's not even mention that the Chieftain only has a 14% higher chance to be killed at the same range despite being rated at only 250mm. There's so much inconsistency in this document that I would take the "500mm KE" with a big grain of salt. Even then.... 500mm KE against BM15/22? Yeah, okay I can see that. But 500mm KE against M829? Or even L23A1? Doesn't seem likely. Let's also ignore that a hull down stationary Challenger has the same 44% probability to be "killed" as a stationary Chieftain...... by an RPG-7. Edit: I should clarify that I think leopard 2 armour is probably somewhere between leopard 1A3 and M1/CR1 in design.

The reason for having thick backplates in the first place is due to this initially being an upgrade program, they would add composite packages to existing Chieftain tanks to improve their armour, they then found that having these thicker back layers is advantageous to minimising damage behind armour. In the case of the aluminium versions, this was probably because aluminium simply isn't good enough on it's own or would be too bulky otherwise. Keep in mind that these proposals and armour designs weren't very good against KE for how bulky they were, Mk5/2 was only rated for 120mm APDS from 1300m for instance (on glacis+turret front, noseplate was overmatched). Everything more or less indicates that the actual NERA sandwiches themselves did very little against KE, most of the protection coming from the faceplate (around 50mm) and the backplate (80-110mm), both of which combined are already sufficient to stop 120mm APDS at ranges exceeding 1km. And while the UK did share info with Germany, it seems rather unlikely that they would adopt the same kind of armour style as they simply had different requirements and ideas. Germany already had experience with spaced armour and it's higher KE efficiency, they were also looking into HHA (jkeiler prototypes, 1A3/4), it's quite likely they kept further developing into more complex arrays with more plates of similar thicknesses as before. Whereas the UK was coming at this from a different angle, previously they'd used thick cast armour with ballistic shapes, adding to this something to counter HEAT warheads (NERA) and something else to make it more durable.... so you get a completely different armour design. IMO it's very weird if Germany would've done a 180 and adopted the UK style of composite/NERA, it seems far more likely that they simply kept working on more complex spaced armour combined with suspended or movable steel plates, each of which would be far more effective against KE than a single NERA sandwich in "Chobham", but less so against CE. So if you're already getting plenty of KE protection from the inserts themselves, it wouldn't be logical to use a thick backplate to do the same job. Why have a thick slab of steel in your armour cavity if you already have decent thickness steel slabs infront of it? Massive oversimplification warning I just don't see a point in having a thick steel slab in your armour cavity if there's already spaced steel plates to do it's job, but more mass efficiently. "Chobham" as on the Mk5/2 (steel) seems a lot less "modular" than the armour of leopard 2, with the backplate being integrated into the chassis of the tank as it's part of the armour array, being the main KE protection component. On leopard 2 it seems like the front and back plate are there for only two reasons: to protect against small arms/ light autocannon fire and to keep fragments or spalling out of the crew compartment, with the main armour being inside the cavity itself, this would allow for more adaptability/modularity. Instead of being stuck with that heavy (and potentially soft) backplate which can become a liability, this design allows for the armour to be consistently upgraded and kept as mass efficient as possible, with as much volume/weight put into replaceable inserts as possible, this also lends itself better to armour arrays that contain comparatively more steel than plastic/rubber, favouring KE protection over CE (which lines up with the protection requirements of leo 2). The multi-layer back plate could be consistent of a HH plate on the "inside" of the cavity (facing the projectile) and then a softer plate behind that, to absorb fragments and minimise spalling, it doesn't necessarily mean it has to be thick or fully inside the cavity. I guess neither of us know for sure, but considering how the Marder 1/2, Puma, Leopard 1A3/4 and leopard 2A5 all seem to use relatively thick spaced steel layers, often fairly evenly through the entire array, I reckon they did something similar on Leopard 2. Just as a sidenote: the additional armour for the Mk5/2 weighed 3.8t for the skirts, 1.3t for the turret and 1.05t for the hull, at most (that includes the 40-60mm thick faceplate). And the Marder 1A3 increased by 5.5t with it's add-on armour (for the entire vehicle), mostly consisting of steel plates on shock absorbing mounts (B&V add-on anyone?). Frankly, I don't see why Germany would use "Chobham" style armour on leo 2 but use completely different technology on it's other AFVs. Hm, yes.... it may be a stretch to instantly assume same thickness of plates for the inserts, but in the interest of logistics and general armour technology they've shown in the past I think thicknesses ranging between about 5-45mm are reasonable, it's consistent with other armour types used in the 70s-90s by the BW. Besides, composite armour doesn't have to follow the Chobham principle, it can easily consist of spaced steel plates that can move or somehow "react" to impacts, on both the Marder 1A3 and Leopard 1A1A1 they use such armour, I don't see why they wouldn't upscale it. NERA can be anything, it doesn't have to be the same design as "Chobham", 2A5 shows that quite clearly I think. True, I should've said plastics or polymers.... could even be something else, though I doubt it's ceramics or explosives. Point still stands though, clearly that sandwich isn't just for CE..... unlike the early M1/CR1 NERA sandwiches that have rather thin steel covers and definitely have a different requirement. I should probably clarify that I consider spaced steel armour just as much composite as "Chobham", it just has a different design.

I have some issues with this: If they intended for the upgraded tanks to feature B tech armour, why base your two prototypes off 8th batch vehicles that come equipped with newer armour from the factory? TVM MAX was intended to be the "maximum" performance improvement, it had all the bells and whistles. TVM 2 or what would become 2A5 is hardly "more capable", it doesn't feature many of the improvements suggested for TVM 1, no hull add-on, no roof add-on, though the additional turret armour is better. The use of new hulls (6-8th batch) instead of older hulls seems to be a compensation for the lack of add-on armour, why make such decisions if you weren't strapped for cash? Seems more like a compromise to me, not just in quantity but also "quality", getting slightly better turret armour for substantially worse hull armour.... Not sure how much that would affect it, but I can point out that the tests themselves seem to have been carried out in similar manners.

Possibly, not sure how exactly they measured it but I think it's reasonable to estimate protection if they took efficiency or remaining armour "type" into consideration. Right now we don't know ofcourse, but I personally doubt they made major mistakes like assuming steel = NERA/whatever the composite uses or that remaining LOS = remaining protection.

Yep, AFAIK they didn't test tandem warheads either, those might stand a much better chance. They did do real firing tests, but only against 3 different SC warheads and I don't know the difference between the two large ones (third is the Carl Gustav's 81mm charge). Edit: checked again, the first charge is a 165mm charge (CE 165), second is a 143mm charge (CE 143 FFV) and the third is the 84mm charge (not 81mm as I previously said, apologies).

^additional information: mantlet couldn't be salvaged/saved, they're working on a new one but had a deadline, so instead they put a camo net over the mantlet to cover it up. This is TVM MIN as indicated by the license plate (Y 907 793) TVM MAX was Y 907 792: Y 907 794 was the last 2A4 from 8th batch. If Y 907 792 was indeed MAX (as indicated) then how come an 8th batch, modified 2A4 had B tech internal armour + D-2 add-ons as shown in the Swedish trials? That would mean they changed the inserts to B tech (huh, cost maybe?) when they did the conversion, or these two tanks were B tech from the start (doesn't make much sense). There's a third option: KVT (modified 5th batch), which was converted to IVT, was also "shown" to the Swedes (for the IFIS), perhaps the Leopard 2 "Improved" slide talks about that one? Seems a bit of a stretch. However, if the TVM indeed did use B + D-2 and was the "German solution" we see in the Swedish comparison, then the improvement in armour might just be down to the add-on and not a better internal armour. Turret add-on definitely changed, hull one we don't know about. So, turret was a rather small improvement, but hull was ~80mm on upper hull/roof (82° AoA means you'd only need an additional 11mm RHA for the add-on thickness). Did they mess up with the indicated armour, or does a B tech leopard 2 with add-on reach these numbers? As previously posted in this thread: 28mm sandwich + 71mm air + 28mm sandwich @ 65° = ~950mm protection against CE. Looks quite similar to the wedges for leopard 2A5. 2A5 prototypes: 1720mm-1850mm CE protection on turret from 0° front -950mm from wedge = 800-900mm for main turret armour B tech requirement: Milan 1 or 600mm+ CE (probably 650-700mm from front) That leaves 250-100mm which isn't explained, could be due to airgap allowing the jet to disperse more before hitting the main armour. If we assume these armour arrays (or similar ones) were used in the wedges for leopard 2A5 and that the 250-100mm discrepancy can be explained or falls within margin of error, then it does seem plausible that B + D-2 = Leopard 2 "Improved" and that 2A5 uses B tech or a modified version thereof as base armour. Only thing that isn't entirely explainable is the (massively) increased KE protection.... but then again, even small impact angle changes (yawing LRP) can have massive consequences.

I recently acquired a copy of this book: There's some interesting things in there, specifically: So, according to tests, M833 ~ M413(DM33) -> 500mm RHA at unknown angle and 2000m (65-68°?).

I can ask my friend again to get a better measurement from the inside using the driver's hatch as reference, though I don't think drawings are necessarily 100% accurate. Quoting their article: Seems like they did verify where the 101mm plate was mounted/welded, I think the only question that remains is how it was mounted, either forward of the weld, in the middle of the weld or behind the weld.... I agree that perhaps more investigation is required. As for the turret, is there any indication that the IPM1/M1A1 increased the front plate thickness? I know of the appliqué plates mounted on M1A1s in GW1, but apart from that, I've never seen much on it. That was my conclusion as well. To be fair, I don't entirely trust the CIA in either case. But this does match up better with all the other circumstancial indicators. L/D of 12? Huh.... could it be that they simply used DM13 APFSDS as simulant and upscaled it a bit? I don't think we should assume BM42 or 32 for that matter, both wouldn't be known to the west at this time, let alone be used for estimates. Yeah, couple that with the lower requirement for CE protection, it does add up. DM13 is still superior to M735, especially if fired from the 120. Seems like it was designed to work against composites or spaced armour, unlike M735. True, though it does appear as if leo 2 had better KE performance, while being tested against slightly less shit rounds than the M1. Besides, I'd still consider DM13 superior to BM15/22, specifically against composites. I very much have come to a similar conclusion though, M1 seems overrated in terms of armour protection due to the requirements often being neglected, same thing with the Challenger 1. The only one of the modern MBTs that seems to have been tested and designed with a somewhat modern threat is leopard 2. Though it clearly "lacks" in CE protection as a result. Sure, but we don't have the luxury of testing it all, so we have to do with estimates and educated guesses :). I think the requirement, previous development and specific steels used already indicate that the armour technology isn't the same. Requirement leopard 2AV: Milan 1 (580mm RHA) and 105mm DM13 APFSDS Requirement M1: 127mm SC (I-TOW?)(640mm RHA) and XM579E1 (pre-proto M735) Already we can see the preference lies more with CE than KE for the M1 and the opposite for leo 2. Previous development: leopard 2 PTs, spaced steel with HHA and ballistic shaping (minimising profile), leopard 1A1A1 B&V add-on (perforated steel plates with plastic/rubber cover)..... Regarding the steels used, you yourself have pointed this out in the past (thanks for that): It doesn't list plates thicker than 45mm, indicating that leopard 2 doesn't use thick backplates such as on M1 or CR1. These would be necessary (I should say preferred) for Chobham style composite. So, if the KE protection doesn't come from the front and backplate, it must come from the inserts. M1/CR1: 30-50mm frontplate (RHA) -> NERA sandwiches with thin steel plates (RHA) and thicker rubber/plastic liners -> thick backlayer 100-110mm (CHA/RHA). Leopard 2: 30-45mm frontplate (HHA) -> spaced steel plates (HHA) between 10-45mm -> 40-45mm backplate (RHA/HHA?). Looks quite different to me, combine that with how the Germans used suspended/dampened spaced armour before (B&V upgrade) it seems quite likely they continued down this path and maybe only used some parts of the UK-GER info sharing from 1974. Let's not forget that the same exact thing seems to be the case with the leopard 2A5 add-on.... spaced steel with a rather low rubber-steel ratio. Oh, dangit, I forgot to look the document itself up.... BRB.

Ofcourse, which is why it's very interesting that the reference threat was the 152mm XM579E1, which is essentially the predecessor to the XM735 APFSDS. That one is teardrop shaped (as we all probably know): It also has a 97.5% tungsten alloy which gives it 18.5g/cc density (page 3). This type of penetrator probably isn't very good against complex armour types, the tip and tapering width wouldn't be advantageous. So, M774 or DM23 (120) for instance will probably perform better than it against the composite of the M1. Also, what's the cent vs L23A1 story? Haven't heard of that one yet. Not sure how that would work, the hull front is ~732mm from straight front and so is the turret, meaning that the turret at + 30° would have less LOS. So while the hull has it's worst protection from straight front, that lines up with the best protection on the turret front (atleast in terms of LOS, we don't know composition apart from exterior plate thickness ofcousre). Essentially, I doubt that the hull's 845mm (~732mm at 30°) would be as good as the turret's 732mm (at 0°), it just doesn't make sense. Depends, did they really underestimate the USSR ammo when we take the design of said ammo into consideration? They underestimated the raw penetration of USSR ammo, but is the performance that good against composites? I tend to think not. The slug type APFSDS lose almost 50% of their penetration at 30° angles because the slug and steel rod seperate (starts happening at 15°), the slug itself would be great against RHA because it's made of WC and going very fast while being very small (70x20mm), but it weighs next to nothing (270g) and due to material type would be very prone to shattering on spaced armour plates. According to the Bauman book, BM15 is 32.1% less effective against 50mm RHA + 70mm air (same as core length) + 200mm RHA than against a 250mm plate, all at 0°. Incidently, these are common characteristics on NATO MBTs such as the M1 and leopard 2, angles on the turret as well as the hull exceed the 30° value in a lot of cases, while such small airgaps are probably quite common as well. All of this combined seems to indicate that against BM15 or even BM22, both the M1 and leopard 2 would have decent to good protection on the turret, it's only when you look at BM26/29 that both tanks start to become more vulnerable. Even then, while M1 doesn't seem very impressive, leopard 2's turret should be notably better, IMO Krapke's threat diagram could apply to BM26/29: All of this is speculation, but it does seem plausible. BM32/42 are a different story though and for this the 1988 upgrades would definitely be necessary, though they do seem sufficient to block said ammo even at PB. We should also note that during most of the 80s, BM22/26 were the most common rounds and BM32/42 wouldn't have been very common. IMO, US got the CE protection just right and Germany got the KE protection relatively right, both could've been better, but then they might've ended up doing an MBT-80.

Just a joke. I was referring to how it looks, those colours are horrendous.

You sure this isn't a better thread? Also, I genuinly hope that add-on package is an april's fools joke

http://www.tank-net.com/forums/index.php?showtopic=37096&page=50 I've been looking for the original source on this for ages, short of buying the Greek magazine that detailed some parts of the Hellenic trials, nothing has come up. Anyone know more about this?

Armour dimensions of the M1A1 in the American Heritage museum (made by a friend): Hull: 24" or 609.6mm to weldline, rumoured 4" plate behind that (101.6mm) (Quoting friend) Seems like there's some empty space there, or he could've missed something, but he agreed that LOS thickness was ~732mm. Turret cheek loader: 29" or 736.6mm perpendicular From front face to loader's hatch on outside: 78" (he had to hook the tape over, so -3" on the pic you see) and from loader's hatch on inside to armour = 41", so turret cheek armour from front = 37" or 939.8mm. Turret cheek gunner: 29" or 736.6mm perpendicular, less angled than loader's side, no measurement to commander's hatch and inside to get overal thickness but we assumed same inner plate thickness. (maybe the GPS wouldn't be able to fit if it was bigger?) So, hull of M1 (1980) was same thickness and turret most likely the same too (732mm LOS), so how come they gave turret higher protection values than hull? Seems a bit odd, CIA gave turret 400mm KE (on a turret variant, we don't know which) and 750mm CE, but hull generally gets values of 350mm KE and 750mm CE..... In any case, reference threat for XM-1 (FSED I think) was XM579E1 (simulating 115mm APFSDS): Penetration was estimated at 161mm @60° and 1470m/s (either PB or 500m ish). UK estimated XM-1 at 320-340mm, which coincides with the 115mm at 800-1200m requirement: As previously pointed out in this thread. This doesn't talk about the XM-1s before the FSED it seems (why would they talk about an outdated design?). So either CIA was talking about IPM1 turret ("long turret") or they somehow increased KE values for turret while keeping CE the same OR CIA was overestimating own armour?.... Anyway, BRL-1 or early versions of Chobham don't seem to be very good against KE relatively speaking, NERA part itself seems to do very little for KE, simulated ammo (XM579E1) isn't the best against composite materials or complex targets. Perhaps OG M1 only had ~350mm effective against KE on both hull and turret and IPM1 increased this to 400 or slightly higher, but I don't think that increasing the thickness of the turret with more NERA seems very efficient against KE. IPM1/M1A1 probably have below 470mm against KE on turret (XM579E1), but maybe more against old slug type APFSDS and definitely less against 80s long rods. This probably led to DU equipped M1s...... to compensate for relatively poor KE protection.

Interesting points: Mantlet weighs 640kg Barrel + breech weigh 1905kg but total assembly without mantlet is 3015kg, so 1110kg for cradle, recoil system, recoil guard, etc. They tested APFSDS with L/Ds in excess of 30. Sales brochure (?) from September 1982.

Thanks, the ones that aren't labelled either BM26 or BM29 seem to be mostly correct though? Strange, this still seems to have the old sabot on it, did Fofanov get this wrong? Do we know if that slug in the back is actually DU? I find this a bit weird too, while Fofanov isn't entirely accurate, he does give a cutaway drawing and it looks different than this picture (though I do think your picture is more accurate and probably the correct) According to Fofanov, the slug is infront of the tail section and not in it, it also has a (tungsten?) cap in the front, while also having the old sabot. So, you think that Fofanov actually got them mixed up? Is BM26 actually the one with the slug in the tail section and new sabot while BM29 is the one that has the penetrating cap at the front, slug before tail section and old sabot? I did know about BM42 and had those pictures you linked, thanks :). You wouldn't happen to know where those cutaway drawings come from? (I've seen similar ones in some DIRD projectile and warhead identification guide).

Alright, so I found this picture online and couldn't find a description of it anywhere, put some names of rounds on it, but not entirely sure about some: Mostly care about the top right section, curious about BM29, haven't seen much written about it.

So it would traverse between firing each one to get a good coverage? Interesting that they went for a bit of increased complexity as opposed to what ROSY does (similar amount of charges per "turret" AFAIK).

And how do you know? They clearly did their own tests, with reference armour inserts and also with their own developed add-ons. Again, why do you think so? Everything points to the opposite, they tested the armour as would be on the test vehicles, afterwards they added their own add-ons and tested again. Which is exactly what I pointed out....if you go lower armour volume you need to compensate with higher density of materials, which almost always in turn means similar weight.... However, high thickness/volume of armour is generally more mass efficient than the same mass of armour in a smaller volume. Mass will always remain relevant, but you need to take into account mass efficiency to get anything out of it.

The Swedes "simulated" the armour by asking the companies involved for specifications on how to make said armour, which was then produced locally according to specs and tested. They did also produce their own add-on armour for these tanks and because they didn't get the exact measurements on the armour carrying parts, they had to make these themselves: http://www.ointres.se/projekt_stridsvagn_ny.htm He also mentions tests were conducted in each country on the base armour. So, this isn't a "simulation" as much as it is live testing. Hold up, so you're saying that the leclerc when using smaller armour packages with denser armour somehow makes turret weight irrelevant? Isn't that the exact opposite, less volume with denser materials -> same/similar weight....? I don't see how that makes the turret weight irrelevant, it still needs the same armour mass to achieve the same level of protection unless you're using more advanced, more mass efficient materials. Generally speaking, less dense, higher volume armour is more mass efficient..... just look at 2A5 vs M1A2.... 59.7t vs 62.5t.... stops DM53 vs doesn't stop DM53.

Same story as the export Abrams or CR2, yet you don't see people saying that about leos, nor Leclercs.

Perhaps because the crew are placed further apart and closer to the outside. I'm sure there's a reason why the Swedes decided to render the important area as bigger. I agree that the actual crew compartment is lower, but the gun certainly isn't and that's still counted as fighting compartment AFAIK. Still, autoloader =/= more effecient internal layout, especially not when you have silly comparisons like that M1 turret vs the Type 90 turret.

But the actual fighting compartment as viewed from the front is wider, I had some internal volume figures somewhere, I'll see if I can dig those up.

Autoloader isn't the reason why: Despite having an autoloader and only 3 crew, the Leclerc's fighting compartment volume is higher than that of the Leo 2. It isn't about autoloader's, it's about internal volume and the armourweight/volume required to protect this internal volume. You forgot to point out that this means lower elevation angles for the gun, reliability issues for the autoloader, less frontal protection and a myriad of other issues. Also, that's possibly one of the worst drawn M1 turrets I've seen so far. Even then, the M1A1 turrets are vastly better in frontal protection than the Type 90 because it's got ~270mm more LOS while also adding more weight in armour going from A1 to A1HA than the Type 90 has total for it's special inserts.