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Ronny

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  1. Tank You
    Ronny reacted to Mighty_Zuk in Practicality of using ABM against fighters   
    @Ronny Ramlaen has somewhat touched on that issue but didnt explain it so I will.
     
    You can take it as a rule of thumb that the faster these missiles are in the first stages, they farther and higher they need to get. I repeat, farther and higher they NEED to get.
    The PRS-1M is a great example, much like the Sprint, as they both have a ridiculous first stage speed.
     
    This speed creates an extremely high temperature around the missile while it's in the atmosphere. This causes disturbances that make these missiles practically blind not only to external sensors and C2 systems, but also their own onboard active sensors. 
     
    Current ABMs (counter medium range to ICBMs) deploy the final stage outside the atmosphere. Only there they no longer have disturbances, and communication with ground control is enabled. At the same time they are also finally able to activate their own seeking sensors.
     
    So unless the aircraft you are talking about are outside the atmosphere, an ABM can't do anything against them. All they have to do to counter an ABM is make a slight turn or slight change is speed, and that's it.
    That is, if the search radar doesn't automatically filter them out in the first place to save processing power.
     
    Only ABM that are built to defeat ballistic missiles in the terminal stage, have an anti-aircraft capability.
    This includes but is not limited to:
    S-300/400
    PAC-2/3/4
    David's Sling
    MEADS
    Arrow 2
     
  2. Tank You
    Ronny reacted to Mighty_Zuk in Practicality of using ABM against fighters   
    You haven't contributed anything to this thread. Even if his posting is "bad" (IMO, it's not. He doesn't know how to take in the replies he gets, but makes generally interesting questions), that doesnt change the fact that in this thread your SNR is also 0.
  3. Tank You
    Ronny reacted to Collimatrix in Practicality of using ABM against fighters   
    If we (over)simplify the question, then it turns out that making the missile faster doesn't reduce it ability to successfully intercept.

    For a given G capability, the turn radius of a missile will decrease as its closing speed increases.  However, as the closing speed of the missile increases, the amount of time in which the target can deviate its flight course in order to try and dodge the missile also decreases.  You can essentially describe the sum of possible trajectories of the missile as a trumpet-shaped cone, and for the target as well.  As long as the target's cone sits inside the missile's cone, the missile is kinematically capable of hitting the target.

    If you make the missile faster, for a given G limit its cone becomes narrower.  However, the target's cone becomes shorter.  You can simplify this further by assuming that the missile's current velocity vector is pointed along an intercept lead course that will intersect with the target if the target does not change course.  If the target cannot produce more lateral acceleration than the missile can, it cannot force a miss.  At least in theory.
     
    The problem becomes one of very arcane technical questions.  Just how precisely does the missile system know the target's location and velocity?  What are the resolution and accuracy limits of this targeting?  How many times per second are these numbers checked and re-checked?  How often does the missile alter its course?
  4. Tank You
    Ronny reacted to A_Mysterious_Stranger in Shape of APFSDS's core   
    I don't think you're going to get a neat, single answer for all of this.  Penetration is very complicated even when you focus only on rigid OR eroding regimes.   APFSDS occupy a transitional region between those two, meaning it is likely to be even more complex. 
     
    For example I did more digging by changing search parameters.  One thing I turned up came from army-guide and this interesting point:
     


     
    Completely unsourced but it shows a the potential for multiple factors at work.    I've found sources that allude to nose shape influencing interface defeat, transitions from rigid to eroding penetration and velocity thresholds, and so on.  I'll share the various things I ran across in the hopes it will prove useful.  In no particular order:
     
    CTH hydrocode predictions on the effect of rod nose-shape on the velocity at which tungsten alloy rods transition from rigid body to eroding penetrators when impacting thick aluminium targets
     
    Abstract:


    Design of hard-target penetrator nose geometry in the presence of high-speed, velocity-dependent friction, including the effects of mass loss and blunting
     
    Abstract


     
    INTERIOR AND TERMINAL BALLISTICS OF 25g LONG ROD PENETRATORS
     
    Introduction:



    Investigation of Oblique Penetration I: The Effects of Penetrator Leading End Shapes on Unyawed and Yawed Impacts
    Abstract



    TERMINAL BALLISTICS TEST AND ANALYSIS GUIDELINES FOR THE PENETRATION MECHANICS BRANCH
     
    Introduction:


     
    Penetration of 6061-T6511 aluminum targets by ogive-nosed VAR 4340 steel projectiles at oblique angles: experiments and simulations
    Abstract



    The Effect of Nose Shape in Long Rod Penetration
    (link to free PDF download)
    Abstract:


     
    This one seems related to the one below, so I included it more for completion's sake and informative purposes. 
     
    Comparative Study of Nose Profile Role in Long-Rod Penetration
    Abstract:


     
    Honestly I'm not sure this is very relevant.  It seems more about eroding-penetrator processes and mushrooming vs non-mushrooming.  But it's also about EM guns specifically, so it was worth mentioning.
     
    Interface Defeat of Long-Rod Projectiles by Ceramic Armor
    Abstract:


     
    This is mostly about interface defeat in general vs ceramics, but there is a bit in there about nose shape.  So nose shape may be a factor here.
     
    Interface defeat studies of long-rod projectile impacting on ceramic targets
     
    Abstract:


     
    Analysis of the Noneroding Penetration of Tungsten Alloy Long Rods Into Aluminum Targets
    Abstract



     
    This one seems to be more about rigid penetration, but its also about about LRPs. Worth noting for that 'transitional' aspect I mentioned and the fact nose shape has a huge impact in rigid penetration.
     
    Modeling Threshold Velocity of Hemispherical and Ogival-Nose Tungsten-Alloy Penetrators Perforating Finite Aluminum Targets
    Abstract

  5. Tank You
    Ronny reacted to TWMSR in Shape of APFSDS's core   
    Re your question about supershot round: it is a part that gets discarded during shot, just like sabot. AFAIK it is there to prevent automatic guns from jamming, which could occur if pointy projectile nose is exposed.
  6. Tank You
    Ronny reacted to A_Mysterious_Stranger in Shape of APFSDS's core   
    What I could find: 
    Jacketed Long-Rod Penetrators: Problems and Perspectives
     
     
    Though that is about Jacketed Penetrators, it seems it may still apply to regular APFSDS.  Given it cites Rosenberg and Deckel you might look at their work 'Terminal Ballistics' for more information. 
     
    Possibly more useful is this: 
     
    The Effect of Nose Shape on Depleted Uranium (DU) Long-Rod Penetrators
     
    I apologize for not quoting any of this, but its a 66 page non searchable PDF, and I'm not sure that you can just select parts without reading the whole thing for context since it's specifically about LRP and nose shape for DU rounds (some tungsten is mentioned.) 
     
    Also of possible interest are these reddit posts.  I'm not sure how 'good' it is since we're talking War Thunder (I'm as wary of that as I am of WoT based research) but I figure I'd include it for completeness sake and potential for discussion: 
     
    APFSDS the Science of Ricochets
     
    How tip shapes affect APFSDS performance on sloped armour
     
    I also believe that most APFSDS don't operate fully in the eroding (hydrodynamic) regime and would slow down on impact anyhow.  So rigid penetration effects may apply (nose shape does matter quite a bit there).
     
    Lastly because it may be of interest to someone materials which may be of interest but may not be relevant to the discussion:
     
    Penetrator strength effect in long-rod critical ricochet angle
     
    Interaction between High-velocity Penetrators and Moving Armour Components
     
    PENETRATION OF METALLIC PLATES BY KINETIC ENERGY PROJECTILES
     
    The Relation Between Initial Yaw and Long Rod Projectile Shape after Penetrating an Oblique Thin Plate
  7. Tank You
    Ronny reacted to SH_MM in The Leopard 2 Thread   
    This isn't known (to the public at least). Rheinmetall claims that the Leopard 2 ATD/Revolution reaches a higher level of frontal armor protection than the Leopard 2A5 and would be on par with the Leopard 2A7 (at least this is what they told to Poland when competing against KMW for the Leopard 2PL program) - nobody knows if that is true.
     
    The problem with Rheinmetall's upgrade is that the base armor of the Leopard 2 comes in different configurations and thus it depends on which variant is upgraded with Rheinmetall's solution.
     
    The Leopard 2 ATD/Revolution comes with improved side armor, mine protection kit, roof armor, slat armor for the engine compartment and improved frontal armor, while weighing only 63-64 metric tons - meanwhile the Leopard 2A7 of the German army (no hull add-on armor,  no roof armor, but mine protection kit) weighs 63.9 metric tons. This means that either Rheinmetall's armor is a lot better than KMW's (which might be true to some extend, as it is thicker; when having two armor array of the same weight and similar technology, using more thickness can result in improved mass effectiveness) - or that Rheinmetall's claims are a bit too optimistic. It is probably a mix of both, at least in terms of multi-hit capability the AMAP package doesn't seem to perform too well.
     
    If Rheinmetall's claims were correct, this would mean the Leopard 2 ATD/Revolution is much better protected than the Leopard 2A7 for the same weight.
     
     
    Because these systems look good on paper, but perform bad in tests. Germany tested at least three types of APS for the Leopard 2A7V in the last few years and found all of them lacking (in the eyes of Germany, the development has not been finished yet). A small number of Trophy APS systems is being purchased for the Leopard 2 tanks meant to participate at the VJTF, but only as a stopgap measure.
  8. Tank You
    Ronny reacted to Mighty_Zuk in Contemporary Western Tank Rumble!   
    3/4 of warheads were neutralized. Rafael claims 50% rate IIRC, while IMI's fragment-free grenade offers 90% rate. 
  9. Tank You
    Ronny reacted to Mighty_Zuk in Contemporary Western Tank Rumble!   
    The range of HE is lower than that of APFSDS, in a consideration of only the flight characteristics of the projectile.
    However, what limits APFSDS range is not really how long it can fly. It can go for tens of kilometers with ease. It just won't retain the necessary velocity to penetrate a target. 
    A specific APFSDS could be effective to 3km for one target, 1.5km for another more armored target, and completely ineffective to another even more armored target.
    HE is not range-limited, and with fin stabilizers could fly out to a pretty good range. Russia (UVZ) claims the T-90 can fire its HE shell out to 12km.
     
    It's physically possible, but the bottleneck would be the sights that probably won't even recognize the pixel they're looking at, at that range.
     
    So if you can see a target 6km away, you can be sure lobbing HE shells is possible. In the IDF it's fairly routine to practice firing them out to 5km, and that's not really an exceptional feat in the west or anywhere.
     
    2)That would never be necessary. 60's era tanks with 105mm guns, with APDS/APFSDS are abundant on the market right now. Even the poorest countries have these.
    If munitions are still an issue then worry not. A 105mm will do a crap ton of external damage as well, but with a much better RoF and actually existent munition stockpiles.
     
    And if it comes down to fighting against a more technologically capable enemy, then tanks are actually a liability. Guerilla warfare becomes key.
     
  10. Tank You
    Ronny reacted to Mighty_Zuk in Contemporary Western Tank Rumble!   
    Those aren't stupid questions. Unfortunately some people here are too conservative and early to bark at people for raising questions for which the answers only seem obvious to them.
     
    1)The question of ERA versus NERA is a matter of design philosophies, and wargame analysis.
    In absolute terms, neither ERA nor NERA are more effective from one another.
     
    They both have a linear tradeoff of capabilities. It is a function of single-hit protection, i.e how effective would one type be against only 1 shot, and the total number of shots that armor can take. 
    In a very rough comparison, an ERA can interact with 1 projectile resulting in X penetration reduction. And a NERA armor would defend from 2 projectiles, with only X/2 penetration reduction at a time.
    On average, they are mathematically equal. On the battlefield, certain scenarios will show the superiority of one over the other.
     
    To better understand the situation, you must first understand that actually both western and eastern tanks use NERA of some form, as the key component of their armor. Only for a short time was ERA ever dominant over NERA, and that was at the time of tanks like Leopard 1, AMX-30, and M48/60, because proper composite armor did not exist yet with the quality needed to defeat HEAT or APFSDS.
     
    Next comes the impact probability analysis.
    If a certain area is considered likely to be hit multiple times in tight groupings, over the course of a single engagement, then NERA is the preferred solution, even though again the Soviet tanks used NERA as much as western tanks.
    If a certain area is only likely to be hit once in a single engagement, then ERA is preferred.
     
    This is why on most western AFVs, the first type of applique to appear for side protection was ERA, and only after certain advancements, it moved on to NxRA (will get into that later).
     
    And finally is the system's longevity analysis. Or basically how long the tank is expected to survive in either case.
     
    Soviet tanks were considered more disposable than NATO tanks. Although fiercely competing with the west to create the higher quality tank, part of the philosophy was that even an advanced tank won't survive for very long on the battlefield. Minutes at best.
    Thus ERA, being more effective for a single hit, would basically double the number of shots required to take out the tank, in some of the more likely scenarios.
    And when you double some capability, for seemingly no cost at all, that's something worth doing, and is no longer an incremental upgrade.
     
    In the west, tanks were expected to be more survivable, hence for example the human loader that was more of a spare than an actual necessity for normal operation of the tank.
    With a focus on higher overall longevity of the platform on the battlefield, the ERA would not be more than a minor addition over potent NERA. It would be a single use item in an environment in which designers believed a tank needs to be able to sustain many hits, even if only for the sake of recovery.
    Plus, it would encourage a bad culture of crewmembers' false reliance on a single use item, perhaps not fully understanding the extent of the danger in such belief.
     
    But wherever sufficient NERA was not possible, western philosophy did not exclude ERA at all, and you can see the Bradley for example entirely covered in ERA. 
     
    2)Depends who you're looking at.
     
    USA - Wanted Trophy more than a decade ago but Raytheon lobbied hard enough to delay its acquisition until it can complete its own system, which it eventually never has. 
    Reallocation of funds was also time consuming. Army doesn't always get what it wants, and almost never on time, unless Congress is especially generous.
     
    Rest of NATO - For three reasons mainly.
    First, they are very much disconnected from their MIC and will more often try to subvert the MIC than help it, because of a perceived sense of security.
     
    Second, rest of NATO are being led, not leading new technological trends. Their innovators are their MIC which they don't do nearly enough to support.
     
    Third, the acquisition of arms in Europe is done with the intent of deterrence, not the actual usage of said equipment in combat. Hence why you can still see Leopard 2A4 as the main MBTs of certain countries.
    I've explained a long while ago, in depth, the economical effects of an APS. One of the conclusions was that it is economically unviable to buy AFVs without APS, if the AFVs are to be used during their lifetimes at least once in a medium to high intensity combat scenario. Most combat today is hybrid warfare, which is medium intensity. So basically for most of the combat we see globally, an APS is a must.
    It is only viable to buy a tank without an APS if the tank is not expected to see combat.
     
    That is why countries like the US, Israel, Russia, Ukraine, and Turkey, are seen investing in APS. Even poor Syria does. 
     
    A Leopard 2A7V, and its ancestor the Leo 2, form a lineage of 40 years of service in Germany. At no point were they used in serious combat by the Bundeswehr. Only the VJTF is supposed to be deployed abroad and expected to see combat on short notice, which is why the VJTF tanks will receive an APS. It just didn't get much publicity.
     
    Of course, there are some within NATO who see the importance of capability maintenance and building regardless of the probability of war, and are investing in APS as well. The Netherlands for example are probably going to be the first in Europe to use an APS, on their CV90.
     
    3)Russian ATGMs are not really a good comparison. They simply were never really effective weapons. Only effective within a small range of conditions.
     
    A proper GLATGM would be something like a Spike downsized to 120mm, but today it's hardly necessary. There are two main considerations to this - tools, and tactics.
     
    Tools - a tank battalion never drives alone. It will have infantry support. Infantry on the battalion level will always have an AT element capable of launching ATGMs at standoff ranges, and their vehicles have ATGMs as well, to multiply the output. Other than that, available tools include artillery, that in the modern day use long range guided missiles (+20km range), guided rockets, and guided/unguided shells.
     
    Tactics - when spotting a tank formation of any size, 6-8km away, other options are preferred. Ambush with short range engagement from prepared positions is ideal.
    The next best alternative is actually calling artillery or aviation, because the effects of a sudden barrage are going to be far greater, as opposed to an ATGM volley that would have the core of the formation maneuver away and screening their maneuver, when they see the first missile flying.
    The third best option would be to lob HE shells, not ATGMs, at enemy tanks too far away.
    The reason is that HE can do a lot of damage to the optics, gun, stabilizers, and other external equipment that is key for the effective use of the tank. It could even outright disable tanks by hitting the tracks or the UFP close to the driver's hatch.
    ATGMs pack an HE payload as well, but are far less versatile and substantially more expensive, to the point where it's worth asking whether allocating vital space for them inside the ammo rack is even worth sacrificing other ammo types. HE-MP is just too versatile to not want it in greater numbers.
     
    4)Basically all current MBTs can take a hit from a 152mm howitzer. That is, the crew will live, but the tank will be disabled.
     
    This question is perhaps irrelevant, because howitzers on the battlefield are used in direct mode only rarely and in emergencies.
     
     
    BONUS: Today there is something called NxRA. It differs from NERA and is somewhat of a replacement to it, rather than a competitor.
     
    Anyone can feel free to correct me if I'm wrong, but basically:
    NERA - Non Energetic Reactive Armor. It does not produce any energy on its own. It relies on the energy produced by the projectile and impacts the projectile with proportionately produced energy.
    It's reactive, but more often than not regarded as passive because of its lack of independently energetic components.
     
    NxRA - Non eXplosive Reactive Armor. Much like ERA, and unlike NERA it produces its own energy. However, it's not the blast you'll see with an ERA. It's more tame.
    And the results are an armor that is as survivable as the NERA, but quite substantially more effective per shot than it. Not as effective per shot as ERA or SLERA (self limiting ERA), but it's somewhere close.
     
    Because of this, NxRA is considered more effective than the NERA and ERA, because its per-shot-effectiveness to survivability ratio, is higher than both of them.
     
    You can even see that the NxRA is gaining traction, and is now armoring tanks like the Merkava 4 entirely (or almost entirely), is offered for advanced variants of the Leopard 2, and armors the UAE's Leclerc. 
    It's also used on a plethora of medium AFVs like the CV90, Ajax and ASCOD, etc.
     
    It's just not going to replace ERA everywhere because of a not too good volume efficiency that could make certain vehicles too large.
     
     
    It really was one of the dumbest arguments I've ever heard when rationalizing combat capability degradation programs.
    Basically every army that saw actual combat, decided the potential risks posed by ERA to infantry are greatly outweighed by the risk reductions it offers.
     
    When APS became operational, only then has this idea become a frequent talking point. But APS is far less dangerous than ERA because it neutralizes the projectile's warhead without initiating it.
    All because Raytheon couldn't deal with their loss.
     
     
    LAHAT is only a shitshow if you insist on analyzing its capabilities OUTSIDE of its historical background.
    It was devised for the Merkava 2 tank, long before the Spike even had half the capabilities it has today.
     
    At the time, you needed LoS to the target to fire off a Spike, while the LAHAT allowed you to fire it off without LoS.
     
    Another point you've forgotten is that a helicopter is not required for remote designation. It can be done via infantry. In any event of invasion into Israel, the first line of troops will be border brigades, not equipped with tanks and heavy weapons, but with a great deal of observation and intelligence capabilities. They, and the spearhead units', have plenty of infantry they would allocate to target spotting and designation either for artillery, AF, and whatever. They can easily designate targets for MBTs or helicopters using LAHAT. And they themselves would have a low combat signature.
    Caliber is of course a non-factor because of top attack, hence why Spike missiles (except for SR) always had a relatively weak warhead compared with contemporary designs, even other similar sized missiles developed by the same company.
     
    Only today are LAHAT missiles irrelevant, hence their withdrawal from service a long time ago, and their marketing to non modern armies.
     
    It's not very accurate. The Namer and Merkava 3 and 4 may have ERA in some places.
    It's not confirmed but the Mark 4 has armor plates with the inscription "explosive", and the Mark 3 and Namer have armor modlues with box shapes, suspiciously ERA-like. 
    Besides, certain Nagmachon variants can still be seen with the old Blazer ERA.
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