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Is an APDS Round Unstoppable?

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  • Is an APDS Round Unstoppable?

    With all of the new defensive additions to armoured vehicles in the last 20 years, is there anything around that can defeat a solid shot delivered at hyper velocity?

    It seems to me, and believe me I'm no expert on tank gunnery or armour design, that Cobham armour and reactive plates are only effective (if at all) against hollow charge warheads. Based on how they are designed to work neither CA or RP would even slow down a good piece of spent uranium burrowing its way through steel like butter.

    I could probably look all of this up but I do enjoy the discussions on here. Is there anything that can stop an APDS round from penetrating a modern tank's armour?

    Cheers,
    Dan.
    So long as men worship the Caesars and Napoleons, Caesars and Napoleons will duly rise and make them miserable.

    Aldous Huxley: Ends and Means (1937)

  • #2
    Just to get things going...

    Kinetic energy penetrators or APFSDS(Armour Piercing Fin Stabilised Discarding Sabot) has to deal with MBTs and other armoured vehicles fitted with Reactive Armour.
    Here is an interesting read about the Russian Kontakt-5 ERA against long rod penetrators. http://fofanov.armor.kiev.ua/Tanks/EQP/era.html
    Last edited by Achtung Baby; 11 Nov 12, 01:24.
    "In modern war... you will die like a dog for no good reason."
    Ernest Hemingway.

    "The more I learn about people, The more I love my dog".
    Mark Twain.

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    • #3
      Video evidence not withstanding I find it incredible that an ERA box would have time to explode and disrupt the penetrator.
      I don't doubt the evidence, I just find it hard to comprehend the infitisemally small amount of time a penetrator would take to penetrate the ERA box.
      Common sense tells me that the penetrator would be boring through the main armour before the explosive can propogate to its full potential.
      Kind of like bolting the stable door after the horse has ran off.

      Comment


      • #4
        KE penetrators are molasses-like compared to HEAT penetrators, which are ERA's usual opponent. Modern APFSDS penetrators have a velocity of 1.6-1.8 km/s at the cannon muzzle, compared to 8-10 km/s for the tip of a HEAT penetrator.

        Comment


        • #5
          Originally posted by DogDodger View Post
          KE penetrators are molasses-like compared to HEAT penetrators, which are ERA's usual opponent. Modern APFSDS penetrators have a velocity of 1.6-1.8 km/s at the cannon muzzle, compared to 8-10 km/s for the tip of a HEAT penetrator.
          Agreed but before the HEAT slug can start penetrating, its warhead must explode fully,this must only take a nanosecond but during this time the ERA box is also exploding so I can kind of see how it would effect the formation of a viable jet.
          The LRP on the other hand doesn't have to perform any functions on impact.
          I'm no mathematician but I've tried to come up with a figure representing the length of time a LRP takes to pass a fixed point

          Here goes:

          We'll take the slowest LRP=1600mps

          I think that means that if the LRP was 1m long it would take 1600th of a second to pass a fixed point.They're not that long though (Do you know a typical length?)

          I would therefore say that a 1m LRP takes a maximum of 1600th of a second to pass a fixed point.
          if these amateur calculations are correct,they mean that even when you take into account the physical thickness of the ERA box and the resistance imparted onto the LRP by it,there's not a whole hell of a lot of time for the ERA box to explode before the LRP is through it.
          This confusion could be ended if one of us knew the explosion rate of an ERA box of course.
          My brain hurts.

          Comment


          • #6
            The battle of penetrating rods or HEAT has been going on since WWII. An improvement in certain armor types inspires tank builders to go to the other type of shell. I think back in the 50's they used armor made of fiberglass to defeat HEAT. The reason Chobham is a mixture of layers of ceramic tiles and steel/depleted uranium is so they can combat either type of penetration.

            Pruitt
            Pruitt, you are truly an expert! Kelt06

            Have you been struck by the jawbone of an ASS lately?

            by Khepesh "This is the logic of Pruitt"

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            • #7
              Almost not happening

              When a Sabot round is fire out of a 120mm (almost 5" in diameter) main gun, it will always penetrate a vehicle out to 1600 meters (over 1 mile away).

              After that, depends on the distance, temperature outside (this might affect the accuracy of hitting the target) and the location of the hit on the target (front slope, vs. side, rear, turret, etc....) and it might not penetrate sometimes. But still, the Isrealis are "Master's" at long range gunnery; they have a 105mm on their tanks as a main gun and I doubt they will convert to the 120mm.

              Still, Kinetic Energy from a Sabot round will kill a target and the crew; if not then, later by the DU tips causing cancer to the crew that survives.... (I know of a US tank crewman that was in a vehicle that was hit by "friendly fire" during the "Gulf War I <Desert Storm>. He lived for five years until cancer of his lymphnodes killed him. ).
              Kevin Kenneally
              Masters from a school of "hard knocks"
              Member of a Ph.D. Society (Post hole. Digger)

              Comment


              • #8
                Originally posted by flash View Post
                Agreed but before the HEAT slug can start penetrating, its warhead must explode fully,this must only take a nanosecond but during this time the ERA box is also exploding so I can kind of see how it would effect the formation of a viable jet.
                The LRP on the other hand doesn't have to perform any functions on impact.
                I'm no mathematician but I've tried to come up with a figure representing the length of time a LRP takes to pass a fixed point

                Here goes:

                We'll take the slowest LRP=1600mps

                I think that means that if the LRP was 1m long it would take 1600th of a second to pass a fixed point.They're not that long though (Do you know a typical length?)

                I would therefore say that a 1m LRP takes a maximum of 1600th of a second to pass a fixed point.
                if these amateur calculations are correct,they mean that even when you take into account the physical thickness of the ERA box and the resistance imparted onto the LRP by it,there's not a whole hell of a lot of time for the ERA box to explode before the LRP is through it.
                This confusion could be ended if one of us knew the explosion rate of an ERA box of course.
                My brain hurts.
                Estimates I've seen of the penetrator length in the M829A3 projectile are around 800-860 mm. Estimates of Kontakt-5 heavy ERA bricks have a thickness of 70 mm (a 15 mm thick front plate, 35 mm of explosive, and a 20 mm rear plate). If the APFSDS penetrator is moving at 1.6 km/s, that's 1.6 million mm/s. Using the lower length estimate and discounting any deceleration, the back of the penetrator has to get through 870 mm of space before the ERA brick detonates, which would take it almost 544 microseconds. ERA is always angled pretty severely to normal, so the effective thickness (and time required to get through the ERA brick) increases. The acceleration induced to the plates by the explosive in ERA is typically complete within 6 microseconds.
                Originally posted by Kevin Kenneally View Post
                When a Sabot round is fire out of a 120mm (almost 5" in diameter) main gun, it will always penetrate a vehicle out to 1600 meters (over 1 mile away).

                After that, depends on the distance, temperature outside (this might affect the accuracy of hitting the target) and the location of the hit on the target (front slope, vs. side, rear, turret, etc....) and it might not penetrate sometimes. But still, the Isrealis are "Master's" at long range gunnery; they have a 105mm on their tanks as a main gun and I doubt they will convert to the 120mm.
                Never say never, or always. And the Israelis have used a 120 mm main gun on the Merkava 3 and 4.

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                • #9
                  Originally posted by DogDodger View Post
                  Estimates I've seen of the penetrator length in the M829A3 projectile are around 800-860 mm. Estimates of Kontakt-5 heavy ERA bricks have a thickness of 70 mm (a 15 mm thick front plate, 35 mm of explosive, and a 20 mm rear plate). If the APFSDS penetrator is moving at 1.6 km/s, that's 1.6 million mm/s. Using the lower length estimate and discounting any deceleration, the back of the penetrator has to get through 870 mm of space before the ERA brick detonates, which would take it almost 544 microseconds. ERA is always angled pretty severely to normal, so the effective thickness (and time required to get through the ERA brick) increases. The acceleration induced to the plates by the explosive in ERA is typically complete within 6 microseconds.


                  Never say never, or always. And the Israelis have used a 120 mm main gun on the Merkava 3 and 4.
                  You're better at sums than wot I am!
                  Is a microsecond a one thousandth of a second?

                  Your explanation makes sense to me but is at odds with an explanation I had a while ago:

                  I approached my local university in the hope that they may be able to help me with an idea I had.
                  In a nutshell this was to equip the outer face of tank armour with a "sliding plate" of steel of sufficient thickness to force the LRP to start working on it,as it was doing so ,the plate would skid up and away from the direction of impact.
                  I thought that the sliding motion would act as a pair of shears on the LRP and perhaps snap the thing thus impairing its penetration abilities.
                  Sounds reasonable don't you think?
                  I took this to the uni and secured a physics professor.I gave him the data. He then did various sums and after a few minutes of hmmmming looked up and said it wouldn't work!

                  His reason for this was that the LRP would be through the sliding plate before the plate had time to react,ie,start sliding.Very disappointing

                  Comment


                  • #10
                    Originally posted by flash View Post
                    You're better at sums than wot I am!
                    Is a microsecond a one thousandth of a second?

                    Your explanation makes sense to me but is at odds with an explanation I had a while ago:

                    I approached my local university in the hope that they may be able to help me with an idea I had.
                    In a nutshell this was to equip the outer face of tank armour with a "sliding plate" of steel of sufficient thickness to force the LRP to start working on it,as it was doing so ,the plate would skid up and away from the direction of impact.
                    I thought that the sliding motion would act as a pair of shears on the LRP and perhaps snap the thing thus impairing its penetration abilities.
                    Sounds reasonable don't you think?
                    I took this to the uni and secured a physics professor.I gave him the data. He then did various sums and after a few minutes of hmmmming looked up and said it wouldn't work!

                    His reason for this was that the LRP would be through the sliding plate before the plate had time to react,ie,start sliding.Very disappointing
                    Microsecond is 0.000 001 second
                    Milisecond is 0.001 second

                    Comment


                    • #11
                      Originally posted by flash View Post
                      You're better at sums than wot I am!
                      Is a microsecond a one thousandth of a second?

                      Your explanation makes sense to me but is at odds with an explanation I had a while ago:

                      I approached my local university in the hope that they may be able to help me with an idea I had.
                      In a nutshell this was to equip the outer face of tank armour with a "sliding plate" of steel of sufficient thickness to force the LRP to start working on it,as it was doing so ,the plate would skid up and away from the direction of impact.
                      I thought that the sliding motion would act as a pair of shears on the LRP and perhaps snap the thing thus impairing its penetration abilities.
                      Sounds reasonable don't you think?
                      I took this to the uni and secured a physics professor.I gave him the data. He then did various sums and after a few minutes of hmmmming looked up and said it wouldn't work!

                      His reason for this was that the LRP would be through the sliding plate before the plate had time to react,ie,start sliding.Very disappointing
                      Thanks Rebel. As he mentioned, a microsecond is one-millionth of a second. Your mechanism isn't far off from how heavy ERA works, by the way. But more than just relying on sliding, put some plastic explosive behind the plate and see how fast it moves.

                      Comment


                      • #12
                        Originally posted by Kevin Kenneally View Post
                        When a Sabot round is fire out of a 120mm (almost 5" in diameter) main gun, it will always penetrate a vehicle out to 1600 meters (over 1 mile away).

                        After that, depends on the distance, temperature outside (this might affect the accuracy of hitting the target) and the location of the hit on the target (front slope, vs. side, rear, turret, etc....) and it might not penetrate sometimes. But still, the Isrealis are "Master's" at long range gunnery; they have a 105mm on their tanks as a main gun and I doubt they will convert to the 120mm.

                        Still, Kinetic Energy from a Sabot round will kill a target and the crew; if not then, later by the DU tips causing cancer to the crew that survives.... (I know of a US tank crewman that was in a vehicle that was hit by "friendly fire" during the "Gulf War I <Desert Storm>. He lived for five years until cancer of his lymphnodes killed him. ).
                        People get cancer all of the time, despite never being anywhere near depleted uranium. Those kind of stories are just fear-mongering.

                        Short answer is, it depends on what the round is fired at. There is not such thing as an impermeable object...or an unstoppable force.
                        Quis Custodiet Ipsos Custodes? Who is watching the watchers?

                        Comment


                        • #13
                          Originally posted by DogDodger View Post
                          Thanks Rebel. As he mentioned, a microsecond is one-millionth of a second. Your mechanism isn't far off from how heavy ERA works, by the way. But more than just relying on sliding, put some plastic explosive behind the plate and see how fast it moves.
                          Good grief
                          Can any explosive really develop at that speed,6 millionth of a second!!!?
                          I don't know but isn't that something like light speed?
                          Perhaps I'm just ignorant of the way things work at this level but to a layman like me that is absolutely astonishing,I had no idea.
                          I know from experience that explosions are "damn quick" but to see figures like that amazes me.
                          I have seen PE exploded suspended on a line (so there was no distracting debris clouding the issue) and one second it was there and the next instant there was just a shimmering haze of air.But I always assumed that something like a LRP would be through that haze without even blinking..............Guess not
                          Thanks a bunch for that.

                          I've edited this bit in.

                          The reason I didn't place explosives behind the plate was to get around how "surprising" an ERA explosion could be to Private Smith having a nice cup of tea behind the reassuring bulk of a tank.

                          Comment


                          • #14
                            For reference, in six millionths of a second, a photon will move almost 1.8 million mm (~1.8 km).

                            They do have non-exploding reactive armors that are in use. But beyond the shrapnel from the ERA (which is more of an issue with earlier, light ERA), PVT Smith would still have the fragments from the HEAT warhead or APFSDS bolt to deal with...

                            Comment


                            • #15
                              Originally posted by DogDodger View Post
                              For reference, in six millionths of a second, a photon will move almost 1.8 million mm (~1.8 km).

                              They do have non-exploding reactive armors that are in use. But beyond the shrapnel from the ERA (which is more of an issue with earlier, light ERA), PVT Smith would still have the fragments from the HEAT warhead or APFSDS bolt to deal with...
                              Can I borrow your calculator
                              That wouldn't bother Smith,not if he's just had a nice cuppa!

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