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Post by Rocket Witch on Nov 6, 2016 4:11:05 GMT
1. Why are the devices elliptical instead of spherical?
2. Is it possible (at least in theory) for a conventional gun breech to withstand the use of a nuclear propellant charge?
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Post by jonen on Nov 6, 2016 4:28:45 GMT
In regards to two: 1: Does need to survive to fire more than once? (Am assuming that whatever the gun is fitted to needs to survive.) 2: Do you accept very wide definitions for 'gun'? (Drilling holes into asteroids to place nukes inside them, then plugging the hole with your intended projectile and waiting for an enemy ship to cross into the projected trajectory... Yeah, guidance issues means it's probably not practical.) |
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hal
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Post by hal on Nov 6, 2016 4:52:19 GMT
1. Why are the devices elliptical instead of spherical? I've personally assumed that it's because the nukes are two-point detonating designs (see RA2lover's simulations of various explosive layer designs). Two-point designs are generally more advanced than the older 32-point spherical ('soccer ball') designs - it enables the use of fewer explosives ('swan'-type primaries eliminate the need for slow explosives entirely by use of an air lens) which means less mass and size. Sure. While there is an effective lower limit on nuclear bombs, it's feasible that a very small and low-yield one (the W48 'Davy Crockett' Mk-54 might be the best [known] candidate at a (relatively) puny 10 tons) could be used in some kind of gun, though I'd imagine it'd be horrifically inefficient. |
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Post by cuddlefish on Nov 6, 2016 5:30:50 GMT
The other advantage of two point is presumably that you just need to sync up both sides and the geometry of the system does the rest, rather than having 32 individual detonations which all need to go Just So or the device fizzles.
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Post by Rocket Witch on Nov 7, 2016 18:58:45 GMT
Sure. While there is an effective lower limit on nuclear bombs, it's feasible that a very small and low-yield one (the W48 'Davy Crockett' Mk-54 might be the best [known] candidate at a (relatively) puny 10 tons) could be used in some kind of gun, though I'd imagine it'd be horrifically inefficient. Mm... what would make it inefficient? So much energy the gun barrel would have to be miles long to make much use of it, I guess? |
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hal
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Post by hal on Nov 7, 2016 19:55:58 GMT
Sure. While there is an effective lower limit on nuclear bombs, it's feasible that a very small and low-yield one (the W48 'Davy Crockett' Mk-54 might be the best [known] candidate at a (relatively) puny 10 tons) could be used in some kind of gun, though I'd imagine it'd be horrifically inefficient. Mm... what would make it inefficient? So much energy the gun barrel would have to be miles long to make much use of it, I guess? I was thinking along the lines of 'how efficient is it to use an x-ton nuke instead of just packing x tons of tnt in there' - you still have the same problems as high explosives in that you have to make sure the gun doesn't simply blow up, and now you have to worry about the effects of the radiation messing things up as well, which probably requires further expense to counteract. Also, your 20 tons of tnt would probably be cheaper than it's nuclear equivalent, due to nuclear weapons needed a lot of precise engineering and machining to function.EDIT: As I was typing this it somehow hadn't occurred to me that 20 tons of TNT would take up a lot more room than a 20-ton nuke. Hm. The more I think about it the more it seems likely that the sheer amount of material you save by not having to fit all that TNT in there overcomes the problems mentioned. Small nukes are inefficient uses of nuclear material in and of themselves as well - modern small nukes like the aforementioned W48 use 'linear implosion' where the fissile core is compressed from an oval to a sphere, which is less compression and therefore less explosion out of a given amount of nuclear material, but needs less explosives and therefore less room than better methods. In this case you could try to design a very small yield nuke without worrying about miniaturizing it in this way - though at this point (since as far as I know no nation's nuclear program has attempted to do this) there's not a whole lot of data to go on in terms of how costly this would be. Then on top of all of that, there's still the issue as you mentioned of using the incredible amount of energy you're producing and not wasting large amounts of it. |
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Post by bigbombr on Nov 8, 2016 14:19:14 GMT
Mm... what would make it inefficient? So much energy the gun barrel would have to be miles long to make much use of it, I guess? I was thinking along the lines of 'how efficient is it to use an x-ton nuke instead of just packing x tons of tnt in there' - you still have the same problems as high explosives in that you have to make sure the gun doesn't simply blow up, and now you have to worry about the effects of the radiation messing things up as well, which probably requires further expense to counteract. Also, your 20 tons of tnt would probably be cheaper than it's nuclear equivalent, due to nuclear weapons needed a lot of precise engineering and machining to function.EDIT: As I was typing this it somehow hadn't occurred to me that 20 tons of TNT would take up a lot more room than a 20-ton nuke. Hm. The more I think about it the more it seems likely that the sheer amount of material you save by not having to fit all that TNT in there overcomes the problems mentioned. Small nukes are inefficient uses of nuclear material in and of themselves as well - modern small nukes like the aforementioned W48 use 'linear implosion' where the fissile core is compressed from an oval to a sphere, which is less compression and therefore less explosion out of a given amount of nuclear material, but needs less explosives and therefore less room than better methods. In this case you could try to design a very small yield nuke without worrying about miniaturizing it in this way - though at this point (since as far as I know no nation's nuclear program has attempted to do this) there's not a whole lot of data to go on in terms of how costly this would be. Then on top of all of that, there's still the issue as you mentioned of using the incredible amount of energy you're producing and not wasting large amounts of it. The atomic tockets website mentions using some kind of spherical bunker/cannon hybrid using nukes to theoretically shoot an orion craft into space (without having to detonate additional charges in atmosphere). As for generating sufficient pressure out of the energy released by the nuke (instead of al the energy just vaporizing large parts of your projectile and gun): just add water. |
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