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Sturgeon's House


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Everything posted by TWMSR

  1. Sheffield, max speed is for rapid traverse, f.e. when you need to turn turret from 2'oclock to 6 o'clock or TC align turret position with his Peri. Aiming speeds are minis and maxes for responsive aiming, slow for precision 'sensing', fast for target tracking and FCS solution commands (you do not want do wait too long until gun elevates for shooting far-far away targets).
  2. Could you elaborate your first point? How would you define the part of CH2 turret carcass in the process of defeating penetrator or jet? Could you also elaborate your second point? What would prove what?
  3. Properties of cast turret carcasses of Challenger 1 and Challenger 2 are not crucial for protection of those tanks. It is the last layer of armour array and it is not supposed to stop full-scale attack but to intercept residual jet or penetrator that would pierce special armour modules.
  4. It is not good simulation. BM15 is cored projectile, with tungsten carbide penetrator inside, not steel-only like BM12 or BM17.
  5. The clue seems to be that sabots cannot be considered only or primarly as parasitic mass. Every gram counts, of course, but the most important task of sabot is transfer of acceleration load to projectile, and to do it in such way that would not interfere launching of that projectile and, as result, the bang it would do at the end of it's trajectory. There are many other issues about sabots, also of high importance as a problem of mass, and in many cases interconnected: sealing the bore, stiffeness of sabot, penetrator-sabot interface, ration of bore erosion, risk of projectile balloting, sabot separation. Decreasing of sabot weight must be made with all those mentioned above things in mind. The art of firing a projectile lies in efficiency of terminal ballistics, not pureness of interior ballistics or aesthetics of exterior ballistic. As for hollow design there were many such designs during APDS era. I recall also that 152 mm APFSDS XM578/XM579 got sabot with hollow area. Some modern sabots got external grooves or ribs that both increase stiffeness and decrease weight. But the limit for that designs remains in material behaviour during very high G acceleration, when any asymetric load could lead f.e. to asymetric sabot separation, which then could ruin accuracy or even cause projectile goes wild.
  6. TokyoMorose, thanks for that article. If those numbers are correct, level of mass reduction is phenomenal. There are however some points about that. First of all, M829A1 and A2 are very similar rounds, that got very similar penetrators and hence both uses sabots that are comparable in size. So if A1 sabot indeed weights 4,4 kg and it is stated that A2 sabot is 35% lighter, than it is easy calculation for A2 sabot. M829A3, on the other hand, is very different animal. It got long rod that is longer than just long If it's sabot is made of aluminium it would be heavier than A1 sabot. This is, probably, why in that article exact wording is 'additional 30% equivalent sabot mass reduction'. It does not sounds so simple like 'A2 sabot is 35% lighter than A1 sabot, and A3 sabot is 30% lighter than A2 sabot'. For me, at last, it sounds more like 'A2 sabot is 35% lighter than A1 sabot, and A3 sabot is 30% lighter than A2-technology level sabot if made for A3 projectile'. This makes calculations a bit more tricky, as we do not know mass of A3 sabot if made in A1-technology (aluminum), of A3 sabot if made in A2-technology (1st gen. carbon composite), and as it was eventually made. The other point now, 30% equivalent mass reduction between A2 and A3 sabots. Damn, how they did that? Both sabots are double-ramp design, A3 probably pinnacle of that design, with no easily visible means to reduce mass other than change of material. This suggest that 2nd gen. laminate of A3 sabot got much lower density - up to 30%. I would love to have a good read about that new carbon composites, anyone?
  7. Bore size plays it's role, but double-ramp sabots, developed for high elongation penetrators, needs to be long to properly support the rod during firing. Sabot design is not all about reduction of parasitic mass, it should be light enough, but it has other important tasks. Old Soviet 125 mm metal sabots got it's merits, but using ring sabots and full-bore fins and low elongation penetrators today might be considered as suboptimal. Changing sabot material, as in case of M829A1>M829A2, is one way to go (btw. where did you find information that sabot of M829A3 is 30% lighter than one of shorter's M829A2). The other is novel sabot design. And this is the way that Rheinmetall is said to choose in new developments (DM 73 probably not, KE2020Neo probably yes).
  8. Great idea It is so silly to put parasitic mass into design, why do not use zero-mass sabots instead? And why waste so much energy on muzzle blast? All energy should go into penetrator, it must be easy task.
  9. DM 53 is 13 MJ at the muzzle - with sabot. For penetrator only it would be about 8,5 MJ at muzzle, and a bit less of impact energy at 2000 m. It seeems that Ascalon gives 10 MJ penetrator's energy (muzzle or 2000 m) from the start.
  10. Someone do. It is DE102013101423. https://patentimages.storage.googleapis.com/84/45/e5/ab7a967a9f8dd9/DE102013101423B4.pdf
  11. Maybe it is a matter of being prototype - but turrets on both vehicles that were shown are a bit different. Not only armament (gun itself, it`s craddle, mask) but look also at lower edge of turret. Looks like different masking of "core" turret. We need more better pictures, not just stills from video. Leo 2 turret would need some rework to not only look like Altays, but to be functional (f.e. reposition of sights, slight in case of gunner's, bigger in case of commander's). Sit and wait.
  12. Modified Leopard 2 turret. Applique modules, new fire control, RWS, IFF, but all on orginal turret.
  13. So Turkish bought IMI's M325 and Poongsan K277 HEAT-T ammo for their tanks. And the latter type works so-so.
  14. RH guy, when asked, stated that A1 got new primer, that meet more strict requirements on electromagnetic radiation hazards.
  15. Indeed. But if you look at pictures of Turkish "60s" you can see that it is not uncommon to put spare track links or wheel discs on turret walls. Those parts could be blown off when hit by warhead. In this case there coul be seen splash marks on yellow paint on the left.
  16. Hard to tell. L28 used WC core with WHA cap/nose and steel cup in-between. The cup would not be seen without disassembly, but core and cap material should differ in look. At this picture WC cores of older APDS looks darker than supposed WHA cores of newer APDS. Probably L52, not L28.
  17. 90 mm M36/M41, L/50, HEAT-T M431 (5,8 kg), mv =1219 m/s 90 mm JPz BK, L/40,5, unknown shell type (5,74 kg), mv=1181 m/s It could be expected in case of AP-T M318 (11 kg) mv would be circa 800/m/s when fired from 90 mm JPz BK.
  18. The last statement does not stand for itself. Firstly, AFAIK term "shouldn`t be" is not used commonly in research papers on shaped charge vs ERA. Secondly, ERA bricks of ERAWA family already proved to work vs cumulative jet, and it`s efficiency was not a matter of doubts. From what is known about ERA-jet interactions, rear flyer plate (that one that is chasing the jet) is more important than forward flyer plate. It is good when rear flyer plate is thick, because that means more material get into jet trajectory. It is good when ERA is sloped at last 60 degrees, because it gives more efficient use of movement of flyer plates. In case of ERAWA those conditions are met, to some degree. Another very important condition is velocity of back flyer plate - should be as high as possible, to extend the time of interactions with jet. ERAWA's rear flyer plate is probably slower than forward. But is was already said that ERAWA-2 was still quite good vs some tandem warheads. It is not big surprise that '80s/'90s development is not good enough vs more modern and more potent shaped charges.
  19. That 3-T precursor liner is circa 140-145 degree cone. SCs with so wide angle cones lay in transition area between EFPs and classic jets.
  20. WH 98 seems to be triple warhead. The second charge is smaller, because the jet must fit into cavity made in armour array by the first charge. If the second one is of greater diameter, there is probability, that jet would hit outside crater digged by smaller precursor and it`s distruptive power would be wasted.
  21. Wiedzmin, in case of ERAWA-1 both upper and lower metal parts of case are flyer plates. Mounting beams are not sturdy enough to stop lower part (base) of case movement and are being smashed in the process. So, even if only upper part looks like flyer plate, both are flyer plates. And in ERAWA-2 there is one more plate between H.E. layers.
  22. Because it is copy of 2A46 gun, not 2A46M. Design is old, with single recoil buffer, short cradle, no fast barrel change feature. But materials, some details, finishing touches could be sinicized. One example is barrel, made with more modern technology than orginal, another one are gun trunnions, that fit in vintage, T-54-style frame mounting, not T-62+ sockets integral to turret front casting. It is a bit of steampunk in it, mix of old and new developments.
  23. alanch90, note that "only 100 m/s" lower velocity means about 1800 meters difference in anti-armour performance between faster and slower projectiles versus same, specified target. Militarysta, there is general agreement on obsolescence of RHA equivalent as a way to define projectile performance, from many various reasons. On the other hand there is nothing better we have. Commonly accepted standard, namely NATO targets, are even more archaic, since those arrays today can be pierced probably from 20+ kms. RHA equivalent remains a bit more useful, because it gives some numbers that could be compared with other numbers, of another ammunition types. It is also easier to imagine penetrating power in millimeters/inches than in km/miles. Last but not least, RHA equivalent is still used by producers of ammunition. Let say it, that chart was made in Unterluss
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