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Thread: Explosively injected railgun projectiles

  1. #1 Explosively injected railgun projectiles 
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    Hi! I read that explosively injected railgun projectiles can reach 16-20km/s velocities. So how do these explosively fed railgun projectiles work and how are they injected explosively? And how much velocity can a non explosively injected projectile achieve? 7km/s?


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    Forum Bachelors Degree GoldenRatio's Avatar
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    not sure on the first question. However on velocity that's limited by the amount of power, magnets, projectile size & size of the railgun.

    If you want to get technical. the cern LHC is really just a massive rail gun thats in a closed loop. Its projectiles achieve near the speed of light, however the projectile is only a few atoms


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    How about these coilguns in HALO series? UNSC frigates have 183 meter long coilguns that accelerate a 600 ton depleted uranium projectile to 30km/s impacting with 270000000000000 joules which is 64,5 kilotons of TNT. The frigates of UNSC have a mass of 4000 tons which is a big mistake done by game designers because then they are 1/4th of the density of air... But fans have done some estimations based on the dimension and material the frigates are made of and have estimated the mass to be 1 million metric tons. So how much would the recoil be and how much is the felt recoil and how many g forces does the crew feel from the gun being fired? And would the projectile survive the acceleration to 30km/s because if I have calculated right the projectile will feel 18000000000 kilograms of force resulting from the acceleration? And the projectile would probably melt in the atmospheric entry but would the liquid form projectile dissipate in the atmospheric entry?
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    Quote Originally Posted by Tyzuris Coronati View Post
    How about these coilguns in HALO series? UNSC frigates have 183 meter long coilguns that accelerate a 600 ton depleted uranium projectile to 30km/s impacting with 270000000000000 joules which is 64,5 kilotons of TNT. The frigates of UNSC have a mass of 4000 tons which is a big mistake done by game designers because then they are 1/4th of the density of air... But fans have done some estimations based on the dimension and material the frigates are made of and have estimated the mass to be 1 million metric tons. So how much would the recoil be and how much is the felt recoil and how many g forces does the crew feel from the gun being fired? And would the projectile survive the acceleration to 30km/s because if I have calculated right the projectile will feel 18000000000 kilograms of force resulting from the acceleration? And the projectile would probably melt in the atmospheric entry but would the liquid form projectile dissipate in the atmospheric entry?
    600 tons of depleted uranium is not very likely to burn up before it delivers all of it's kenetic energy to the target. After all at 30kms it's going be going from space to ground in maybe 3 or 4 seconds, and that's not much time to heat up and melt let alone evaporate.

    As far as recoil is concerned, that could be a problem. Bigger is better, but much of that recoil could be countered by acceleration.
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    Quote Originally Posted by Bad Robot View Post
    Quote Originally Posted by Tyzuris Coronati View Post
    How about these coilguns in HALO series? UNSC frigates have 183 meter long coilguns that accelerate a 600 ton depleted uranium projectile to 30km/s impacting with 270000000000000 joules which is 64,5 kilotons of TNT. The frigates of UNSC have a mass of 4000 tons which is a big mistake done by game designers because then they are 1/4th of the density of air... But fans have done some estimations based on the dimension and material the frigates are made of and have estimated the mass to be 1 million metric tons. So how much would the recoil be and how much is the felt recoil and how many g forces does the crew feel from the gun being fired? And would the projectile survive the acceleration to 30km/s because if I have calculated right the projectile will feel 18000000000 kilograms of force resulting from the acceleration? And the projectile would probably melt in the atmospheric entry but would the liquid form projectile dissipate in the atmospheric entry?
    600 tons of depleted uranium is not very likely to burn up before it delivers all of it's kenetic energy to the target. After all at 30kms it's going be going from space to ground in maybe 3 or 4 seconds, and that's not much time to heat up and melt let alone evaporate.

    As far as recoil is concerned, that could be a problem. Bigger is better, but much of that recoil could be countered by acceleration.
    Could the projectile survive the acceleration because the forces of the launch are horrendously strong? Or would it disintegrate during the acceleration?
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    if we are talking about space to surface weaponry why bother with a rail gun at all?

    A rod of god would be much more effective, and easier than depleted uranium. tungsten carbide or steel would work well.

    Or if you want the railgun aspect, you do not need much force, just enough push in the right direction and let gravity take over. If you can find a good source of meteors of sufficient size, you would have a near limitless ammo source.

    An attractant & accelerator placed in orbit near the jupiter asteroid belt would work wonderfully just need to work out the physics of when to launch & what speed to impact the intended target. Not hard mathematics, any decent computer could calculate it.
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    I am not good in math/physics but if anyone could tell me if the 600 ton uranium projectile would survive the acceleration to 30km/s? The coilgun that accelerates it is 183 meters long. And the projectile is about 30ft long and 7ft in diameter. And could anyone here calculate the recoil for this weapon given the fact that the UNSC frigate would be around one million metric tons and also the felt recoil and how much g forces would the crew experience from this weapon being fired?
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    Quote Originally Posted by Tyzuris Coronati View Post
    And could anyone here calculate the recoil for this weapon given the fact that the UNSC frigate would be around one million metric tons and also the felt recoil and how much g forces would the crew experience from this weapon being fired?
    Not possible to tell AT ALL from the information provided, unless the weapon is fixed rigidly into the ship (which is, to say the least, highly unlikely).
    Most guns - mounted ones - have a recoil buffer system and without knowing the allowed length of recoil AND mass of recoiling parts you can't calculate the recoil force.
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    These questions are usually resolved if they are accompanied by, um, er, data.
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    Quote Originally Posted by Dywyddyr View Post
    Quote Originally Posted by Tyzuris Coronati View Post
    And could anyone here calculate the recoil for this weapon given the fact that the UNSC frigate would be around one million metric tons and also the felt recoil and how much g forces would the crew experience from this weapon being fired?
    Not possible to tell AT ALL from the information provided, unless the weapon is fixed rigidly into the ship (which is, to say the least, highly unlikely).
    Most guns - mounted ones - have a recoil buffer system and without knowing the allowed length of recoil AND mass of recoiling parts you can't calculate the recoil force.
    Here is a picture of the frigate. The coilgun is located high in the front end of the ship and you can see the barrel from the coilgun.

    Does this photo help at all?
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    So yes the coilgun is fixed rigidly into the superstructure of the frigate.
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  13. #12  
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    Quote Originally Posted by Tyzuris Coronati View Post
    So yes the coilgun is fixed rigidly into the superstructure of the frigate.
    You can't tell from a single picture.
    And no, from one photo there's no way to tell - or even estimate - the recoiling mass of the weapon, or recoil length.
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    Is it possible to count the force that is applied to the projectile? 30km/s 600 ton projectile 30ft length, 7 foot diameter and 183 meters long coilgun. Do you believe the uranium projectile would survive the forces the acceleration causes or would it disintegrate from the horrendous forces?
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    What is recoiling mass? If that means the mass of the gun let's assume it has the mass of 100000 tons. And what is the recoiling length? If you mean the length of the gun it is 183 meters and the ship is three times longer than that.
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    Quote Originally Posted by GoldenRatio View Post
    not sure on the first question. However on velocity that's limited by the amount of power, magnets, projectile size & size of the railgun.

    If you want to get technical. the cern LHC is really just a massive rail gun thats in a closed loop. Its projectiles achieve near the speed of light, however the projectile is only a few atoms
    It's more like a gauss/coil gun, nothing like rail gun at all.

    --
    Furthermore Uranium is only weakly conductive, not ferromagnetic and only slightly paramagnetic--that completely rules it out as for rail guns unless the penetrator is wrapped in some other material (e.g. sabot style)
    Last edited by Lynx_Fox; January 19th, 2014 at 07:52 PM.
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  17. #16  
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    Quote Originally Posted by Tyzuris Coronati View Post
    Is it possible to count the force that is applied to the projectile? 30km/s 600 ton projectile 30ft length, 7 foot diameter and 183 meters long coilgun. Do you believe the uranium projectile would survive the forces the acceleration causes or would it disintegrate from the horrendous forces?
    You are persistent with this question. It doesn't appear anybody knows the answer for sure, but I can't imagine a dense metal like uranium would disintegrate at this acceleration in space, however that might not be the case in an atmosphere. But that's just a guess on my part.
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