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Post by anonymous on Jan 21, 2019 9:36:43 GMT
Hi. I remember seeing from the blog, some sort of concept about a recoilless gun that works by having a very big, flat cylinder rotate very fast, with the projectiles on the circumference. It fires by releasing the projectiles out of a barrel that is attached tangent to the cylinder. I can't find anything about such a concept on the blog, or anywhere else because I don't remember the name. I only see results about Gatling guns and gunspinning. Does anyone know what I am talking about?
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Post by bigbombr on Jan 21, 2019 11:13:21 GMT
I know what you're referring to, but I can't recall the name either. They're pretty impractical as far as weapons or launch methods go though, so not much research has been done on them.
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Post by AtomHeartDragon on Jan 21, 2019 17:18:56 GMT
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Post by anonymous on Jan 21, 2019 18:26:01 GMT
Hi. That is similar but not quite. I made an image very quickly to show how it is supposed to look: The projectile already has all the kinetic energy it needs because it is, practically, part of the wheel, which is spinning. When the projectile leaves the wheel and enters the barrel, it takes that momentum with it. The wheel doesn't experience any change because what it has lost in mass, it has also lost in angular momentum. It's not applying or experiencing any forces to accelerate the projectile, so it is recoilless. Or at least, that's how I think it works. It has been difficult for me to build and intuition for physics.
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Post by linkxsc on Jan 21, 2019 18:54:18 GMT
While yes it is a very real concept, the max muzzle velocity of this type of weapon is quite low, on par with conventional cannons, while being significantly more complicated to build and use.
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Post by airc777 on Jan 21, 2019 19:37:08 GMT
Hi. That is similar but not quite. I made an image very quickly to show how it is supposed to look: The projectile already has all the kinetic energy it needs because it is, practically, part of the wheel, which is spinning. When the projectile leaves the wheel and enters the barrel, it takes that momentum with it. The wheel doesn't experience any change because what it has lost in mass, it has also lost in angular momentum. It's not applying or experiencing any forces to accelerate the projectile, so it is recoilless. Or at least, that's how I think it works. It has been difficult for me to build and intuition for physics. Looks like it'd throw a pumpkin pretty good. m.youtube.com/watch?v=iH-KGJmvxjQ
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Post by apophys on Jan 21, 2019 23:32:55 GMT
The only way to get a truly recoil-less gun is to throw stuff equally in the opposite direction of the projectile.
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Post by AtomHeartDragon on Jan 22, 2019 19:59:13 GMT
Hi. That is similar but not quite. I made an image very quickly to show how it is supposed to look: The projectile already has all the kinetic energy it needs because it is, practically, part of the wheel, which is spinning. When the projectile leaves the wheel and enters the barrel, it takes that momentum with it. The wheel doesn't experience any change because what it has lost in mass, it has also lost in angular momentum. It's not applying or experiencing any forces to accelerate the projectile, so it is recoilless. Or at least, that's how I think it works. It has been difficult for me to build and intuition for physics. You don't get to cheat the deadliest S.O.B. in space like that.
No, I am actually not an ME fan.
Basically, you have a spinny object that suddenly separates. One part goes flying one way, the other, goes flying the opposite way. The exact minutiae of your spinny object and its mode of separation are irrelevant.
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Post by dragon on Jan 22, 2019 23:35:34 GMT
Actually, it's kind of an interesting case, because it does seem that it would be indeed recoilless, in the sense of a classic "kick" - because you're accelerating the projectile along a circle. What it does is cause your firing platform to spin in the opposite direction, and that is your "recoil". A bit counterintuitive, but that's how it should work. When the object separates, it isn't by an application of force, but by removing the centripetal force. That said, I'm not sure if this "rotational recoil" would be any easier to manage than normal one. Of course, if you manage to keep the pellets spinning in their track once accelerated, the time of launch and the acceleration can be separated in time, which might help with that.
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Post by linkxsc on Jan 23, 2019 1:16:52 GMT
Actually, it's kind of an interesting case, because it does seem that it would be indeed recoilless, in the sense of a classic "kick" - because you're accelerating the projectile along a circle. What it does is cause your firing platform to spin in the opposite direction, and that is your "recoil". A bit counterintuitive, but that's how it should work. When the object separates, it isn't by an application of force, but by removing the centripetal force. That said, I'm not sure if this "rotational recoil" would be any easier to manage than normal one. Of course, if you manage to keep the pellets spinning in their track once accelerated, the time of launch and the acceleration can be separated in time, which might help with that. Either way, if I throw a 1kg projectile 1km/s to the right, yes there might be some changes in rotation of my whole ship, but my whole ship is also going to accelerate some amount to the left.
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Post by bigbombr on Jan 23, 2019 7:07:06 GMT
Actually, it's kind of an interesting case, because it does seem that it would be indeed recoilless, in the sense of a classic "kick" - because you're accelerating the projectile along a circle. What it does is cause your firing platform to spin in the opposite direction, and that is your "recoil". A bit counterintuitive, but that's how it should work. When the object separates, it isn't by an application of force, but by removing the centripetal force. That said, I'm not sure if this "rotational recoil" would be any easier to manage than normal one. Of course, if you manage to keep the pellets spinning in their track once accelerated, the time of launch and the acceleration can be separated in time, which might help with that. Sir Isaac Newton would like to clobber you over the head with conservation of momentum. It will have recoil.
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Post by airc777 on Jan 23, 2019 16:29:27 GMT
Easier way to do a 'recoiless' gun if that's what you're trying to achieve is just to build it like a real life 'recoiless rifle'. You build a gun with an open breach that vents exhaust gases in equal and opposite directions. Not to be confused with a rocket launcher, a recoiless rifles projectile does not contain it's own propellant and all of the acceleration is done inside the barrel. This would have limitations in CDE, you couldn't build a turret that points directly 'up' away from the craft, because it would vent exhaust gases directly at the craft which would reflect off the hull and impart recoil forces on it, but this is as close as you can get. Really though, recoil forces are a tiny, tiny fraction of the masses of ships in CDE, the energy losses from reaiming the gun and position keeping delta V should never be a concern. Optimize your guns for effect on target, not effect on operator. Spaceships aren't infantry, you can always build a bigger spaceship to be your weapons platform.
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Post by AtomHeartDragon on Jan 24, 2019 6:54:25 GMT
Easier way to do a 'recoiless' gun if that's what you're trying to achieve is just to build it like a real life 'recoiless rifle'. 'Easier' as in 'actually doable'.
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Post by doctorsquared on Jan 26, 2019 1:38:28 GMT
Hi. That is similar but not quite. I made an image very quickly to show how it is supposed to look: The projectile already has all the kinetic energy it needs because it is, practically, part of the wheel, which is spinning. When the projectile leaves the wheel and enters the barrel, it takes that momentum with it. The wheel doesn't experience any change because what it has lost in mass, it has also lost in angular momentum. It's not applying or experiencing any forces to accelerate the projectile, so it is recoilless. Or at least, that's how I think it works. It has been difficult for me to build and intuition for physics. I wonder if I could hypothetically build a railgun like this where the conductive rails were curved, thus allowing for the slug to accelerate over a longer distance to avoid shattering the projectile while still sitting in a smaller size envelope?
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Post by newageofpower on Jan 26, 2019 4:14:32 GMT
I wonder if I could hypothetically build a railgun like this where the conductive rails were curved, thus allowing for the slug to accelerate over a longer distance to avoid shattering the projectile while still sitting in a smaller size envelope? Helical railguns already exist, but they're impractical as they massively increase stress on the rails, another driver of weight.
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