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Suggestion for a Tank round design

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  • Suggestion for a Tank round design

    Hi,

    As far as I know, tank ammunition is limited in size majorly due to the limited space for carrying ammunition. But when I look at the tank ammunition design, it brought up 1 question...

    Why not make the cartridge of the round to be a rectangular prism? With the same volume for the casing, you can store significantly more ammunition, or with a larger casing for more charge, you can store the same amount of ammunition.

    So yeah, is there any fundamental problems with this?


  • #2
    Fundamentally, I'm not quite sure. A couple things you need to look at:

    You'd have to check the aerodynamics of the round itself, see how having a square casing will affect the flight path (I'm guessing it will be negligible.)

    You'd need to retool a good couple thousand tanks to fire square ammunition which would include a new barrel and new calculations for the FCS, or just wait for the next tank design, which leads to the next point:

    Money. There are thousands upon thousands, if not millions of 105mm and 120mm rounds lying in warehouses all around the world just waiting to be fired so the companies can manufacture more. What are you going to do with all of those shells?

    A technicality: The design of a round tank shell, by necessity, leaves room between each shell since they can't be stacked too close due to their shape. This gives the loader more room for a better grip on the shell. Having a square design would negate that advantage, making loading time slightly longer, which makes time to shot longer, which means that instead of 4 rounds in 20 seconds, you might be going down to 3 rounds in 20 seconds. That might not always make a difference, but in some cases like the Valley of Tears in 1973, rate of fire was a very important factor.

    Now, the Merkava 4 has a total of 46 shells. 10 in a semi automatic magazine in the turret, two groups of 17, one on each side of the rear entrance in the hull, and 2 APSFDS rounds that are sort of hidden away in the turret next to the gunner's compartment. The way the 17's are set up is as follows:

    XXXXx Entrance xXXXX
    XXXXx Entrance xXXXX
    XXXXx Entrance xXXXX
    xx________________xx

    Each "X" is a square shaped fire resistant casing for one shell. The small "x"s are slightly shorter casings that will only hold an APSFDS or HEAT round, due to the size of the turret. The large "X"s can hold APSFDS, HEAT and Flechette rounds.
    Meddle not in the affairs of dragons, for you are crunchy and taste good with ketchup.

    Abusing Yellow is meant to be a labor of love, not something you sell to the highest bidder.

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    • #3
      Originally posted by bigross86 View Post
      Fundamentally, I'm not quite sure. A couple things you need to look at:

      You'd have to check the aerodynamics of the round itself, see how having a square casing will affect the flight path (I'm guessing it will be negligible.)
      Doesn't the casing stay in the tank?

      You'd need to retool a good couple thousand tanks to fire square ammunition which would include a new barrel and new calculations for the FCS, or just wait for the next tank design, which leads to the next point:

      Money. There are thousands upon thousands, if not millions of 105mm and 120mm rounds lying in warehouses all around the world just waiting to be fired so the companies can manufacture more. What are you going to do with all of those shells?
      put it into the MGS v2? I donno

      A technicality: The design of a round tank shell, by necessity, leaves room between each shell since they can't be stacked too close due to their shape. This gives the loader more room for a better grip on the shell. Having a square design would negate that advantage, making loading time slightly longer, which makes time to shot longer, which means that instead of 4 rounds in 20 seconds, you might be going down to 3 rounds in 20 seconds. That might not always make a difference, but in some cases like the Valley of Tears in 1973, rate of fire was a very important factor.
      You can easily design a handle that allows you to pull the tank shells out.

      Now, the Merkava 4 has a total of 46 shells. 10 in a semi automatic magazine in the turret, two groups of 17, one on each side of the rear entrance in the hull, and 2 APSFDS rounds that are sort of hidden away in the turret next to the gunner's compartment. The way the 17's are set up is as follows:

      XXXXx Entrance xXXXX
      XXXXx Entrance xXXXX
      XXXXx Entrance xXXXX
      xx________________xx

      Each "X" is a square shaped fire resistant casing for one shell. The small "x"s are slightly shorter casings that will only hold an APSFDS or HEAT round, due to the size of the turret. The large "X"s can hold APSFDS, HEAT and Flechette rounds
      So the Merk has square shells? does it provide an advantage?

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      • #4
        Doesn't the casing stay in the tank?
        Which is why I said it would be negligible.

        put it into the MGS v2? I donno
        The MGS already has a 105mm cannon. To use square rounds you'll need a new cannon and a brand new FCS, including calculations. Once again, money.

        You can easily design a handle that allows you to pull the tank shells out.
        True, but there is also friction between the shells. Between the base plate and the shell itself there is a groove where they meet up, and if one of those grooves catches on another one you could end up ripping open the whole shell, if you pull hard enough

        So the Merk has square shells? does it provide an advantage?
        No, the Merk has round shells which sit in square casings until they are loaded into the magazine in the turret or fired. The Merk uses the same type of 120mm round that the US Army does, and also has US Army rounds loaded into the FCS. The APSFDS ballistics are slightly different, but the HEAT are almost identical
        Meddle not in the affairs of dragons, for you are crunchy and taste good with ketchup.

        Abusing Yellow is meant to be a labor of love, not something you sell to the highest bidder.

        Comment


        • #5
          Originally posted by bigross86 View Post
          Which is why I said it would be negligible.



          The MGS already has a 105mm cannon. To use square rounds you'll need a new cannon and a brand new FCS, including calculations. Once again, money.



          True, but there is also friction between the shells. Between the base plate and the shell itself there is a groove where they meet up, and if one of those grooves catches on another one you could end up ripping open the whole shell, if you pull hard enough



          No, the Merk has round shells which sit in square casings until they are loaded into the magazine in the turret or fired. The Merk uses the same type of 120mm round that the US Army does, and also has US Army rounds loaded into the FCS. The APSFDS ballistics are slightly different, but the HEAT are almost identical
          Fair enough, I tried :P

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          • #6
            Now I am no Physicist, but I think it comes down to physics. A circle maximizes surface area, and cimbustion in a circular chamber will get more power, than a rectangular chamber.

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            • #7
              how about a hexagon casing if you want the shells to tile the magazine space?
              sigpic"If your plan is for one year, plant rice. If your plan is for ten years, plant trees.
              If your plan is for one hundred years, educate children."

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              • #8
                The round could be round inside of a square sabot, that is not problem is you increase barrel size. The real problem is using a square breach/barrel and making sure the propellant burn and the massive pressure it generates does not cause a failure of the breach or barrel.

                Cleaning would also be an issue

                I am thinking the total surface area of the barrel would go up as well making guns much heavier. For a western tank already close to max possible weight on existing bridges, this might require a reduction in the weight of armor or force a reduced three man crew with all the disadvantages that entails.

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                • #9
                  they've designed triangular caseless ammunition for small arms - the projecitile would be round - but the cartridge is normally larger in diameter than the projectile - so the cartridge can support the round in the rack, only the chamber needs the unusual shape, it could have radiused edges, to reduce stress and ease cleaning. It would weigh more than a comparable cylindrical chamber but it would be hundreds of pounds not unmanagable in weight. The round should be rimless to get the full advantage in stacking.
                  sigpic"If your plan is for one year, plant rice. If your plan is for ten years, plant trees.
                  If your plan is for one hundred years, educate children."

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                  • #10
                    I think the idea is to have only the CASING of a different geometrical configuration for loading. The projectile still has to be round to go down the barrel (rifled or smoothbore).

                    Since the casing is usually bottle-necked it seems logical to change the shape of the main part of the casing for more compact stowage. Unfortunately, that does not work.

                    It was tried out on a much smaller scale with .45 caliber pistol ammunition called Trounds. They didn't gain much popularity.

                    But in tank ammunition, having the casings touch each other (whether they are copper or copper plated steel) is not a good idea at all. In the M-41 Walkers I used to drive, each round was in a separate loading rack. We had racks under the gun and racks to the right side of the driver as well as a ready rack of 10 rounds stowed upright. That was still a good load out of 80 rounds per tank. But in any arrangement, no casing was ever in actual contact with another casing.

                    The same thing with ammunition stowages aboard a Naval warship. Let's take the 5"/38 that I'm most familiar with. The propellent cases were stowed in a separate magazine from the projectiles. The magazine racks for either casing or projectile were designed to provide absolutly NO physical contact with each other.

                    I know this takes up space, but it's the safest way.

                    Besides, though you can push a copper casing blank through dies to make it square, hexagonal or whatever --- what the heck do you think it would cost to bore out the chamber of the gun to accept such a casing? And what kind of machinery would you use?
                    Last edited by RustyBattleship; 30 Sep 10,, 01:35.
                    Able to leap tall tales in a single groan.

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                    • #11
                      It seems like it could be done, that things like this have been tried, and it seems clear it would be very expensive, and probably have a poor return on investment. You could use EDM (Electron Discharge Machining) to machine the chambers, the project isn't very economical anyway.

                      I like the Merkava ammo layout, especially the rear door to reload through
                      sigpic"If your plan is for one year, plant rice. If your plan is for ten years, plant trees.
                      If your plan is for one hundred years, educate children."

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