4 ms·

Afaik that's exactly what happened with railguns: they were tested at something like mach 11, but it turned out that they just made nice holes in the targets, i

by aasasd 5y ago

Afaik that's exactly what happened with railguns: they were tested at something like mach 11, but it turned out that they just made nice holes in the targets, instead of delivering the energy to the targets themselves. So the speed had to be dialed back. (Frankly I don't know if this makes much sense from the physics standpoint, but it's what I read in passing.)

KennyBlanken 5y ago
The railgun test videos I've seen were a lot more than "just make nice holes." At that energy level you have significant damage from spalling from anything the projectile passes through, the superheated metal the projectile actually passes through is launched everywhere, there's the shockwave of the projectile, etc. That's easily enough to be anti-personnel, incendiary, and obliterate electronics and cables and pipes and hoses. And have lots and lots of penetration, which on a ballistic arc could mean exiting below the waterline, and I imagine something traveling at supersonic speeds hitting water probably does some pretty impressive things. If you send one of those projectiles through a magazine, missile battery, or fuel bunker - a lot of people are going to have a very, very bad day.
dredmorbius 5y ago
This is something that's hard to appreciate with any energy-transfer mechanism: If you reach energies that exceed the capacity to transfer energy, you're just wasting effort. For kinetic systems, the projectile-target interaction is critical. A flimsier target actually needs an impact to be spread over a larger area. Think of a pellet shot through tissue as opposed to, say, a blast of sand or salt. There are some analogues with subatomic particles and fast/slow neutrons (slow neutrons are far more effective at sustaining nuclear reactions, as they effectively "stick around" where they're more likely to interact with other nuclei for a longer period of time, and the apparent cross-section of the target nuclei appear larger). https://www.radioactivity.eu.com/site/pages/Slow_Fast_Neutrons.htm https://www.radioactivity.eu.com/site/pages/Slow_Fast_Neutro...

by aasasd 5y ago

KennyBlanken 5y ago

The railgun test videos I've seen were a lot more than "just make nice holes." At that energy level you have significant damage from spalling from anything the projectile passes through, the superheated metal the projectile actually passes through is launched everywhere, there's the shockwave of the projectile, etc. That's easily enough to be anti-personnel, incendiary, and obliterate electronics and cables and pipes and hoses. And have lots and lots of penetration, which on a ballistic arc could mean exiting below the waterline, and I imagine something traveling at supersonic speeds hitting water probably does some pretty impressive things. If you send one of those projectiles through a magazine, missile battery, or fuel bunker - a lot of people are going to have a very, very bad day.

dredmorbius 5y ago

This is something that's hard to appreciate with any energy-transfer mechanism: If you reach energies that exceed the capacity to transfer energy, you're just wasting effort. For kinetic systems, the projectile-target interaction is critical. A flimsier target actually needs an impact to be spread over a larger area. Think of a pellet shot through tissue as opposed to, say, a blast of sand or salt. There are some analogues with subatomic particles and fast/slow neutrons (slow neutrons are far more effective at sustaining nuclear reactions, as they effectively "stick around" where they're more likely to interact with other nuclei for a longer period of time, and the apparent cross-section of the target nuclei appear larger). https://www.radioactivity.eu.com/site/pages/Slow_Fast_Neutrons.htm https://www.radioactivity.eu.com/site/pages/Slow_Fast_Neutro...