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Pardus

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Posts posted by Pardus

  1. Quote

    The KEW-A3 APFSDS and M829A4 use the SCDB technology to achieve greater muzzle velocities, but operating at a higher chamber pressure at 21°C (but due to the fact that SCDB is temperature-insensitive, these rounds won't exceed the pressure limit at higher temperatures). This option was suggested by Rheinmetall Nitrochemie about 18 years ago, but not taken.

     

    Well TIPS is SDCB based according to RhM, so not sure I follow?

     

    Is there any documentation which describes exactly what the difference between DM63 and DM63A1 is?

  2. On 11/24/2020 at 5:29 PM, SH_MM said:

    None of that suggests anything regarding summer. The mean temperature in Germany is 10°C: https://de.statista.com/statistik/daten/studie/914891/umfrage/durchschnittstemperatur-in-deutschland/

     

    Well I did find this:

    0sDUuT.png

    Seems to say that DM63 has the same performance as the max of the DM53? 

     

    The possible 80 m/s increase in MV is also interesting, and makes you wonder wether this is what has been achieved with the DM63A1.

     

     

  3. 8 hours ago, SH_MM said:

    Performance as in penetration scales linearly with KE, if the shape of the penetrator is designed to optimize it. As Rheinmetall doesn't measure penetration using steel, but rather focuses on complex armor arrays only (customers have to pay extra, if they want a test campaign against pure steel targets), it would be easier to achieve a 20% increase in penetration than actually achieving a 20% higher muzzle energy.

     

    If the penetrator is modified to take advantage of it, yes. But the original premise was that the penetrator remained the same, and that it was only the propellant that was "hotter".

     

    Anyway that the tanker might have been alluding to performance with the L55A1 was just a theory, one which you obviously don't agree with. Fair enough.

     

    8 hours ago, SH_MM said:

    Three pictures from Turkish service...

     

    Also, do you think DM53 will look identical to the presentation pictures?

     

    It certainly seems like it:

     

    11008160-524882644318204-859512749-n.jpg

     

     

    This difference in finish makes me wonder wether a new alloy could've been introduced from the DM63 onward to maintain performance similar to the DM53 at common european summer temperatures. The statement "Same high performance as DM53" could suggest this. Either that, or like I said earlier it's simply done so they're distinguishable without having to read the fine print on the SABOT. Not claiming either to be true, I am simply wondering since I find this sudden change perculiar.

     

    ktICm1h.jpg

     

     

  4. 20 hours ago, SH_MM said:

    Penetration doesn't scale linear to muzzle velocity - just look at the equation from Lanz & Odermatt. For the DM53, the increase in muzzle velocity when fired from the L/55 rather than the L/44 barrel is less than 5%; the improvement in armor penetration is quite a bit greater than 5%...

     

    I am well aware that penetration doesn't scale linearly with MV, hence why I said a 14.2% increase in MV jives well with a 20% increase in penetration.

     

    The point is that RhM is talking about penetration when they refer to the percentage wise increase in performance with the Rh120 L55A1 & the Rh130 L51, and not KE. I think they made that clear in their press release:

    25128747685_b2def23cc0_z.jpg

     

     

     

     

    20 hours ago, SH_MM said:
      Reveal hidden contents

    m02006120800210.jpg

    Qxe592U-fy_0shAEpr3i1m2rYO4czhwsa91GlWHR1454506307_titel-dm63.jpg

    DM63 with black tip

     

     

    I had a feeling you would pull out those presentation pictures, problem is the actual in service DM63 doesn't seem to look like that, but rather like this:

     

    c5lrvftwuaaeo29.jpg

    ZSrypy_eW5g.jpg

     

    pti9581svlb31.jpg?auto=webp&s=29d7c06d62

     

     

     

    And here cutaways of the DM63 & DM53 (don't mind the length/width measurements, they are clearly just guesses, dimension wise DM53 & 63 look the same):

     

    DM63

    DM63.2.bmp

     

    DM53

    DM53+dwa.jpg

     

     

    So like I said dimensionally there doesn't seem to be a discernible difference between the penetrators, but there is an outward difference in colour, which could indicate a different/newer tungsten alloy being used for the DM63 - or it could simply be a visual way of telling the two apart, we don't know.

     

     

  5. 15 hours ago, SH_MM said:

    Performance of guns is measured in kinetic energy, not by penetration.

     

    Yet when RhM wrote of the Rh 130 and it's 50% increase in performance, they specified that increase as being in "penetration & effectiveness". 

     

    15 hours ago, SH_MM said:

    The muzzle velocity of DM63 is 1,720 m/s at 21°C; only the DM53 using its hotter (and more temperature dependent) propellant charge reaches 1,750 m/s at 21°C ambient temperature. Given the projectile weight being presuambly identical between DM53 and DM63 (no reported changes to projectile, exterior dimensions are identical), this results in a muzzle energy of ~12.4 MJ at 21°C ambient temperature. At 2,000 m/s, the muzzle energy would be 35% higher (I previously wrote 38%, but this was with a projectile weight that was off by a sligth margin).

     

    Well there are changes between the DM53 & DM63 projectiles, wether they are just superficial or new materials are used in the construction is unclear to me. But they are visibly different atleast in appearance, with the DM53's tip being all black whilst the in service DM63's I've seen are metallic with a black stripe.

     

    Also I wonder why DM53A1 & DM63 wouldn't be usable in the L/44, whilst DM63A1 is? What modification was done from DM53A1/DM63 to DM63A1? (Sabot design?)

     

     

  6. 10 hours ago, SH_MM said:

     

    Negative. The DM53A1 was introduced after the DM63. It is a modification of the original DM53 using the new SCDB propellant first introduced with the DM63. All DM53A1 were created by converting existing rounds.

     

    The DM63A1 is a new version of the DM63 designed to be compatible with all 120 mm smoothbore guns without modifications, whereas the DM63 only worked with the L/55 and modified L/44 guns as per old Rheinmetall press releases:

    "Dank eines neuen Antriebs kann die DM63A1-Wuchtmunition – im Gegensatz zu allen bisher weltweit verfügbaren Munitionstypen – nicht nur in der jüngsten kampfwert-gesteigerten Variante des Kampfpanzers Leopard 2 verwendet werden, sondern erhöht auch die Kampfkraft anderer Plattformen mit 120mm-Glattrohrkanone. Dabei sind keine Umrüstungsmaßnahmen erforderlich. Mit ihrem temperaturunabhängigen Antrieb verfügt die neue Munition über ein Alleinstellungsmerkmal, das weltweit seinesgleichen sucht."

     

    So rather than being improved in performance and hence limited to the L/55A1 gun (and the purely hypothetical L/44A1), the DM63A1 was designed for greater compability with the L/44, L/55, M256, CN120-26/52, etc.

     

    Even the L/55A1 utilizing its raised pressure limit fully wouldn't reach 2,000 m/s firing the DM63's sub-projectile, as this would require an increase in kinetic energy by 38% rather than the advertised 20%.

    The DM63+, DM73 and the supposed DM73 Neo rounds will be limited to the L/44A1 and L/55A1 guns. Neither of these rounds is in service yet, as there are no MBTs compatible with them. The DM63+ however is supposedly ready for introduction since 2019.

     

     

     

     

    As far as I recall they advertized a 20% increase in penetration performance, not kinetic energy, and going from 1,750 to 2,000 m/s (+14.2%) seems likely to increase penetration by about that much (+20%). Also where have you heard of DM63+ ?

     

    So designation discussion aside, I am fairly convinced the tanker could've refered to the MV achieved by the new L55A1 gun. Getting MV off by more than 200 m/s as a gunner in the type just doesn't sound right.

  7. 30 minutes ago, MoritzPTK said:

    Your argument doesn't make sense, sorry. The DM63A1 has been around even before development for L/55A1 & L/44A1 has been started. And btw the Munitionsmerkblatt does not show an increased pressure.

     

    Well consider the following:

    DM53A1 was a DM53 using a new less temperature sensitive propellant, DM63 later followed also using temp independant propellant, as I understood it merely being a redesignation of the DM53A1. Later DM63A1 appears, around the same time L55A1 is first announced (2014-2016), and is described as the most advanced and capable tungsten APFSDS-T round in the world. 

     

    So it's either that or DM63 is completely seperate from DM53, which is not how I've understood it.

     

    In short I suspect the German tanker was alluding to performance of the L/55A1, and not simply speaking nonsense.

  8. 15 hours ago, MoritzPTK said:

    No, the gun just supports a higher chamber pressure. It does not mean that current rounds have increased pressure, velocity or muzzle energy.

     

    I know what it means, but since the tanker quoted 2000 m/s, there's a chance this is actually the performance of what's in service with the new gun. Remember the DM63A1 is a new round different from the DM53A1 & DM63, likely using a higher pressure propellant charge infront of the same penetrator to take advantage of the L55A1's added capability. The future DM73 is going to add a new penetrator to boot.

     

    Going from 1,750 to 2,000 m/s is a 14.2% increase in velocity, which jives well with a 20% increase in penetration.

     

    In short the tanker might very well have been refering to performance of the L55A1 + DM63A1 combination.

  9. Small recap, the German tanker who in a previous video was talking about a MV of 2000+ m/s might have been refering to performance of the L55A1 with the DM63A1 round. According to RhM the higher chamber pressure results in a 20% increase in performance over the L55 with the DM53/53A1/63.

     

     

  10. 17 hours ago, Yoshi_E said:

    I had that file already in my folder... guess i overlooked it or got deterred by the language. Thats why this thread is a gold mine :)
    The swedish document was difficult to translate, but I manged to find everything other than "Framförare vikt : 36kg" Translation is something like: "Front - Recoil reducing". Im assuming its part of the hydraulics / recuperators, but the "Front" part in it doesnt match that.

    I updated my post, though the total mass is still off by some 540kg. Other than the cradle tube i cant think of other locations where this weight could be. Any ideas?

    @Pardus:
    240mm thickness
    728mm wide (Swedish documents list 910mm including the bearings)
    500mm tall
    The central hole should be around 310 mm in diameter (from the Swedish document)
    The smaller ones are larger on the inside and smaller on the front, but in general it should be 30-80mm in diameter.


     

    Based on:

      Reveal hidden contents

    WNvDyhx.png


     

     

    Ok, using those measurements I get 698 kg for a solid block, no holes, using a density of 8 g/mm3. With the holes 595 kg sounds about right, so RHA does make sense based on that. 

     

    420mm NERA + 240mm RHA should make for some pretty impressive protection. Using a 0.5 RHAe modifier for Tech B armour you get 210mm RHAe + 240mm RHA backing, so that's a 450mm RHAe mantlet.

  11. On 5/17/2020 at 7:53 PM, Scav said:

     

    Why all this guessing?
    https://drive.google.com/file/d/0B4xitrrBUDsYckRhSXNNSXpKbkE/view?pli=1
    Gun cradle weight of 595kg, and all the other stuff you can probably use translate for (this is most likely for Strv 122 as well, not Strv 121).
    So gun cradle on 122 is steel, not titanium, weight in this location doesn't matter as much as it's right on the pivot point, inertia and balance doesn't change a whole lot because of it.
     

     

    What is the weight calculation that suggests steel based on, a solid or hollow trunnion? Also what measurements are used besides the 240mm thickness? (incl. size & depth of all the holes)

     

     

     

     

     

     

     

  12. On 5/14/2020 at 11:24 PM, Yoshi_E said:

    A counter argument I could think of is that titanium quickly shatters, meaning it would create a lot of spalling when penetrated, yet no spall liner was applied there.

     

    I don't think titanium actually shatters, it's fairly ductile eventhough its very hard.

  13. 11 hours ago, SH_MM said:

    It does not rust... just like stainless steel.Paint is hardly an evidence.

     

    True, but using stainless steel wouldn't make much sense due to weight IMO. 

     

    A solid titanium block with holes drilled into it is my best guess, as this would provide the best protection for its weight. 

     

     

     

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