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Sturgeon's House


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Everything posted by SH_MM

  1. Ukrainian ATGMs via andrei's blog: https://andrei-bt.livejournal.com/917573.html
  2. Well, if you include TUSK as armor kit for the Abrams, then you also have to include the different Theatre Entry Standards (TES) armor kits (three versions at least) of the Challenger 2. The base armor however was most likely not upgraded. The Leclerc is not geometrically more efficient. It could have been, if it's armor layout wasn't designed so badly. The Leclerc trades a smaller frontal profile for a larger number of weakspots. It uses a bulge-type turret (no idea about the proper English term), because otherwise a low-profile turret would mean reduced gun depression (breech block hits the roof when firing). There is bulge/box on the Leclerc turret roof, which is about one feet tall and located in the centerline of the turret. It is connected to the interior of the tank, as it serves as space for the breech block to travel when the gun is depressed. With this bulge the diffence between the Leopard 2's and Leclerc's roof height is about 20 milimetres. The problem with this bulge is, that it is essentially un-armored (maybe 40-50 mm steel armor); otherwise the Leclerc wouldn't save any weight. While the bulge is hidden from direct head-on attacks, it is exposed when the tank is attacked from an angle. Given that modern APFSDS usually do not riccochet at impact angles larger than 10-15° and most RPGs are able to fuze at such an angle, the Leclerc has a very weakly armored section that can be hit from half to two-thirds of the frontal arc and will always be penetrated. The next issue is the result of the gunner's sight layout. While it is somewhat reminiscent of the Leopard 2's original gunner's sight placement for some people, it is actually designed differently. The Leopard 2's original sight layout has armor in front and behind the gunner's sight, the sight also doesn't extend to the bottom of the turret. On the Leclerc things are very different, the sight is placed in front of the armor and this reduces overall thickness. This problem has been reduced by installing another armor block in front of the guner's sight, but it doesn't cover the entire crew. The biggest issue of the Leclerc is however the gun shield. It's tiny, only 30 mm thick! Compared to that the Leopard 2 had a 420 mm gun shield already in 1979. The French engineers went with having pretty much the largest gun mantlet of all contemporary tanks, but decided to add the thinnest gun shield for protection. They decided to instead go for a thicker armor (steel) block at the gun trunnions. Still the protection of the gun mantlet seems to be sub-par compared to the Leopard 2 (420 mm armor block + 200-250 mm steel for the gun trunion mount on the original tank) and even upgraded Leopard 2 tanks. The Abrams has a comparable weak protected gun mantlet, but it has a much smaller surface. The Challenger 2 seems to have thicker armor at the gun, comparable to the Leopard 2. Also, the Leclerc has longer (not thicker) turret side armor compared to the Leopard 2 and Challenger 2, because the armor needs to protect the autoloader. On the other tanks, the thick armor at the end of the crew compartment and only thinner, spaced armor/storage boxes protect the rest of the turret. So I'd say: Challenger 2: a few weakspots, but no armor upgrades to the main armor Leclerc: a lot of weakspots, but lower weight and a smaller profile when approached directly from the turret front M1 Abrams: upgraded armor with less weakspots, but less efficient design (large turret profile and armor covers whole turret sides) So if you look for a tank that is well protected, has upgraded armor and uses the armor efficiently, the current Leopard 2 should be called best protected tank.
  3. SH_MM

    105x617 DM53 APFSDS-T?

    Oh... sorry for the mistake. This photo was posted on a German forum labeled as 105 mm DM53. Sorry for the stupid mistake, I should fact check their claims next time.
  4. SH_MM

    Contemporary Western Tank Rumble!

    I am innocent, S. Zaloga used the false form in "M1 Abrams vs T-72 Ural".
  5. SH_MM

    Contemporary Western Tank Rumble!

    Based on the graphs you posted earlier, the 120 mm DM13 and 120 mm DM23 APFSDS have rather short penetrators, but also a rather large diameter. This is relevant, since penetration increases with diameter for a given length (more accelerated mass = more kinetic energy; penetration scales with kinetic energy). A slightly thinner rod with greater length would overall be superior, but technology and/or other requirements resulted in a diameter of 32 mm for the DM23 APFSDS (thinner tungsten rod with the available alloys did shatter too often). The velocity of the DM23 after traveling 2,000 m is 1,529 m/s according to Swiss firing tables, but these list the muzzle velocity at only 1,640 m/s. So either the DM23 has a muzzle velocity of 1,640 m/s rather than the usually reported 1,650 m/s or the differences are caused by the Swiss measuring methology or are result of a local modification to the 12 cm PzKan 87 (Swiss designation for the DM23). If the latter cases are true, the impact velocity should be ~1,539 m/s instead. Given that the penetration efficiency of shorter, thicker rods is more, it seems that the DM23 might achieve a penetration per length of above 1 against German HzB A steel: (from Anderson and Riegel III, 28th International Symposium on Ballistics, "Estimate of penetration/perforation performance based on semi-infinite penetration data") The problem is that exact informations regarding the specific steel alloy are rather scarce. HzB. A (and other steels of the HzB classification) existed in several versions with different alloys and hardness levels. In so far it is hard to convert the exact penetration data into RHA penetration. For the graph from the previous post, the steel hardness was said to be 255 on the Brinell scale. Based on the plotted data, the DM23 might achieve between ~ up to 1.05 P/L, so its 360 mm long penetrator would result in a penetration of 378 mm into semi-infinite HzB. A steel. I don't have access to the source from which the data is taken (research paper by Hohler and Stilp, who apparently work for the German Fraunhofer institute), so it is unknown to me wether the steel target was sloped or not. The penetration against sloped targets would be higher than unsloped ones. As this is semi-infinite penetration, the perforation should be higher (meaning: DM23 would probably punch a hole through a 390 mm thick HzB. A steel plate under the same conditions). As for the 120 mm DM13: It is hard to say due to its unconventional construction. The BM-42 Mango APFSDS (which seems to be the closest thing in terms of internal penetrator construction) supposedly achieves a penetration slightly greater than the combined tungsten penetrator length; it has a higher muzzle velocity, but due to the fin construction a greater V-drop (Fofanov lists V-drop of Soviet 125 mm APFSDS ammo as between 60 and 140 m/s/km; given that Mango has full calibre fins, it should be significantly more than 60 m/s/km). Maybe the steel sheat helps increasing the penetration efficiency by simulating a thicker rod/lower L/D ratio? The DM13 should have slightly above 1,500 m/s velocity at 2,000 m distance according to the US graph from the last post (probably 1,510 - 1,520 m/s). That and its shorter rod should lead to a lower penetratioon than DM23 by quite a bit... how much? I don't know. Maybe it is 320-350 mm, if the steel has any positive effect on armor penetration. Otherwise it would again be close to a P/L of 1 (if DM13 behaves like a conventional monoblock penetrator), which would lead to a penetration of only ~310-320 mm. Perforation and penetration against sloped targets might again be higher. The penetrators of both the M833 and the 120 mm DM23 APFSDS have rounded tips, which performs slightly worse than flat-tipped penetrators against sloped target (but penetration still should be higher than against unsloped ones). Source is a Rheinmetall presentation from 2002. It used to be on DTIC, but I cannot find the full presentation at the moment... maybe the link expired or it was removed... The M111 Hetz was capable of penetrating the original T-72's hull armor at very short ranges (some sources say 500-800 metres maximum). The T-72 had a glacis consisting of 80 mm steel, 105 mm stekoplastika (glass-fibre reinforced plastic) and 20 mm steel sloped at 68°. The T-72A had a different layout: 60 mm steel - 105 mm stekoplastika - 50 mm steel (this is also 10 mm more steel), which was more effective against AP(FS)DS ammo. On later models, a 16 mm thick steel plate was added to the hull, improving protection further. The late production model of the T-72A featured spaced hull armor. The M111 Hetz could never defeat the turret armor except for maybe a direct hit near the gun mount, where the armor thickness was only ~300-350 mm. The turret reaches a thickness of more than 475 mm at the well armored cheeks.
  6. SH_MM

    General AFV Thread

    South Korea plans to copy the PL-01 mockup tank...
  7. SH_MM

    APC/IFV armor in details

    A few photos regarding the Boxer's armor: General: Note that the Boxer is - like the AMV - not protected against RPGs in its basic configuration. Additional armor packs or active protection systems have to be installed. Frontal hull armor: Upper section of the frontal hull / driver's hatch: Side armor: Additional roof armor against artillery bomblets:
  8. SH_MM

    Contemporary Western Tank Rumble!

    The chart is correct. The labeling might be a bit confusing: the T-72M1 referenced in the table is not the basic T-72M1 (i.e. Object 172M-1-E5 or Object 172M-1-E6) but rather the T-72M1M (Object 172M-1-E7), which is a T-72M1 with the more advanced NERA armor of the T-72B. Later this was export variant was superseded by the T-72S (Object 172M-1-E8) as true export model of the T-72B. At least on T-72M1M tank was operated by the Republic Guard in Iraq. Rheinmetall marketed its 105 mm smoothbore guns as capable of defeating the T-72M1M (aswell as the T-72S and T-72B), which the normal 105 mm rifled guns L7 and M68 were incapable of doing. They tried to persuade the US Army to buy smoothbore guns for the Stryker MGS among others. Due to its rarity, the existence of the T-72M1M remained unknown for some while and I haven't seen any clear data to whom exactly how many T-72M1M tanks were sold. I don't think that the "basic" belongs to the T-62 version, but rather is meant to show that this is the basic threat for which the mentioned APFSDS ammunition was adopted. The values clearly reflects the T-62M. As for the penetration achieved by the M833 APFSDS: 400 mm against steel armor at normal combat ranges is not possible. The length and velocity of the longord penetrator are not enough to achieve such levels of performance. I.e. the M833 has a 427 mm long penetrator, as you can see in the following images: The following graph taken from a declassified document shows the reduction of the velocity of several APFSDS types over ranges. As one can see, the impact velocity of the M833 APFSDS at 2,000 metres (typical combat range used to measure armor penetration) will be slightly below 1,400 m/s. The following charts shows a comparison of different methods for measuring normalized penetration (i.e. LOS penetration against a sloped target) in relation to the length of the high-density longrod penetrator of an APFSDS round. It compares two mathematical solutions (the forumula from W. Lanz & W. Odermatt aswell as a sub-module of the ALEGRA software suite) with actual measurements (the dots) which are interpolated using a polynomial fit (spline interpolation). Looking at the chart, the length and velocity of the M833 would roughly result in a factor slightly below 0.8 penetrated steel thickness per penetrator length (P/L). A value of 0.8 multiplied with 427 mm will result in an estimated armor penetration 341 mm. Keeping in mind that the graph below is calculated for tungsten rods, the DU penetrator might (based on the exact criteria) perform better; the US Army Research Laboratory (ARL) has established that there is no difference in armor perforation (punching a hole through a steel target), but a difference for armor penetration (punching a hole into a steel target without fully perforating it) - so it isn't really clear wether this matters. Earlier work from ARL suggested a 8-10% lower penetration for tungsten rods, which would suggest 360-370 mm penetration (or rather 180-190 mm sloped at 60°) at 2,000 m distance.
  9. SH_MM

    Tanks guns and ammunition.

    Rheinmetall's 25 x 137 mm PMB 090 APFSDS with tungsten penetrator defeats 35 mm steel sloped at 60° at a range of 1,000 m, although older documents from Oerlikon list the same penetration at 1,200 m distance (probably a result of different penetration criteria). The 25 mm APFSDS from GD should achieve a very similar penetration, maybe a tiny bit lower due to its (negibly) lower velocity (5 m/s) and shorter penetrator.
  10. SH_MM

    Land 400 Phase 3: Australian IFV

    The Vilkas (Lithuanian Boxer) is fitted with the Samson Mk II RWS for two reasons, which aren't true for Australia. First of all, it seems that the marketing campaign for the Boxer to Lithuania was handled by KMW. AFAIK KMW and Rheinmetall are following a system similar to how the Eurofighter is sold to foreign countries (sometimes one company takes over all responsibilities for deal, sometimes another is responsible). Lithuania never tested the Boxer with the Lance turret, but rather tested the more expensive variant with the Puma's turret. The second (and more important) difference between the two countries is the fact that Lithuania couldn't afford the original offer. They would have chosen another vehicle, if the Samson Mk II RWS wasn't adopted for cost-cutting measures. Australia on the other hand has the money and already signed a contract with Rheinmetall... You are making this too simple. In reality the contract probably includes clauses that prevent both sides from canceling it without having to pay a huge sum of compenstations. Then there is the political backlash (i.e. Rheinmetall not building the announced factory in Australia, local politicians and MPs would be pissed). Rheinmetall is not only delivering the Lance turret, but the whole Boxer and hundreds of trucks (incl. some which are already in service). There is much more on stake than just having to find a new supplier for turrets or even for wheeled 8x8 combat vehicles. Last but not least, Australia would become an unreliable customer for all members of the arms industry. You don't cancel a billion dollar deal over something simple as turrets (specifically if there isn't even an official requirement for phase 3 contenders to use the Lance turret) without loosing all your credibility. Why would any arms manufacturer make any contracts with Australia, if there was a chance that Australia cancels the deal after a contract has been signed, because they change the requirements/agreements afterwards? If you were BAE Systems & Patria, you'd abuse the fact that there would be no competition after the Boxer CRV is canceled. Just ask for twice or three times as much for the AMV-35 in such a case (something like this happened in India, where the Russian supplier - after the 125 mm APFSDS deal with IMI was scrapped due to anti-corruption laws - decided to ask for a hefty markup to sell BM-42 Mango rounds to India). Lance is modular. Integrating an APS should be really easy; however they also could opt for a hull-mounted APS. Remember that everything on the Lance turret except the basic structure with the operators' station is contained in various add-on parts. Just put the APS in such an add-on part and you're done with adding an APS to Lance.
  11. SH_MM

    The Leopard 2 Thread

    Austrian General Robert Brieger announced that the current configuration of the Leopard 2 (the Leopard 2A4Ö) can ot be supported (supplied with spare parts) anymore in the (near) future. Therefore Austria has to upgrade or scrap the Leopard 2A4 fleet, the latter seems to be unlikely. Last year Austria reactived 16 Leopard 2A4Ö tanks (bringing the active fleet from 40 to 56), which originally were meant to be cannibalized for spare parts. https://twitter.com/Bundesheerbauer/status/1024014240032714752
  12. SH_MM

    Land 400 Phase 3: Australian IFV

    Recon has to be light, but LAND 400 phase 2 was not the Reconnaissance Vehicle, but a Combat Reconnaissance Vehicle. The Boxer CRV replaces the ASLAV, which is also not a recon vehicle.
  13. SH_MM

    The Leopard 2 Thread

  14. Puma is too small... (in German): http://www.deutschesheer.de/portal/a/heer/start/aktuell/nachrichten/jahr2018/august2018/!ut/p/z1/hY9PC4JAEMW_kbP-t-NKJBJaaFnuJRZdbMN2ZdmkQx--XQJv0hwezHszv2GAwBWIoDMfqOZS0NH0LYlu0SbIM69GReadMcJNddo3RelmhwAauPwbISZGK4UR1D2D1jDidYYPNRAgPXM6KZi2qpnQ3OigqJbKmaTSo01eSpnE4T20yN2mKFxOuZ_UT3AcBUG0zdPKAh90pu9ll3b2aWjvVPQjO8oO_4zpuUvKMhy-m8qbQg!!/dz/d5/L2dBISEvZ0FBIS9nQSEh/#Z7_694IG2S0MG2UA0AVRTKVMN1GO3 Depending on seat location, the height limit for soldiers in the Puma is either 1.91 metres (equal to somehwere between 90-95 percentil of the height of a German man) or 1.84 metres (equal to only ~75 percentil of the height of a German man). This design decision was originally accepted in 2003, because not caring much about taller soldiers allowed to increase the level of protection for a given weight. In 2013 the German army requested to change the Puma's design to incorporate taller soldiers (probably because the end of conscription lead to a smaller pool of soldiers being available). Before 2013 the army didn't asked for the changes, because investigating the internal ergonomics (which limit the soldiers' height) was only seen as reasonable on vehicles close to the series production configuration. Apparently the decoupled seats and other security related factors are main factors limiting the maximum soldier height in the Puma's rear compartment, so improvements to them could allow taller soldiers to fit into the specified height range.
  15. SH_MM

    The Leopard 2 Thread

    A few more photos. I didn't know that the armored vehicle restoration group of the German tank museum has its own facebook page. The tank is in driving condition.
  16. Maybe it's the processing unit? Other APS also make use of only a single central computer system to deal with multiple launchers and sensors.
  17. About Trophy on the Merkava IV (via otvaga forum): Note that the APS does indeed replace some of the side armor (which can be seen in the lack of bolts required to hold the NERA panels and also the hatch that is visible at the bottom). On the armor modules, there are normally lots of small bolts in that location: I guess that explains to some extend why Trophy on the M1 Abrams seems to be so much larger...
  18. SH_MM

    Name that AFV: The New Tank ID thread

    Prototype IFV RU 361 developed by Henschel for the Marder program. You should have removed the number on the hull before posting...
  19. SH_MM

    Tanks guns and ammunition.