Slashdot Mirror
Navy Debuts New Railgun That Launches Shells at Mach 7
Jeremiah Cornelius writes: "The U.S. Navy's new railgun technology, developed by General Atomics, uses the Lorentz force in a type of linear, electric motor to hurl a 23-pound projectile at speeds exceeding Mach 7 — in excess of 5,000 mph. The weapon has a range of 100 miles and doesn't require explosive warheads. 'The electromagnetic railgun represents an incredible new offensive capability for the U.S. Navy,' says Rear Adm. Bryant Fuller, the Navy's chief engineer. 'This capability will allow us to effectively counter a wide range of threats at a relatively low cost, while keeping our ships and sailors safer by removing the need to carry as many high-explosive weapons.' Sea trials begin aboard an experimental Navy catamaran, the USNS Millinocket, in 2016."
Hot expanding gases, you're pushing a projectile at Mach 7 through air that doesn't really have anywhere to go.
It is called plasma. It happens when you heat gases beyond a particular limit.
A 23 pound slug traveling at Mach 7 is displacing a lot of air very quickly.
Do you think that air will get colder?
i thought once I was found, but it was only a dream.
Oxygen, it's in the air...
fine vaporized particles of metal...
*poof*
Oxygen is pretty combustable if you get it hot enough. Friction is a bitch yo.
At last the US Navy, for so long the joke of the high seas, will become a force to be reckoned with.
how many pairs of boxer shorts should you own?
Well, judging form the pictures, this is the one disposable razor I wouldn't want to be shaved with.
Ezekiel 23:20
Actually, do we know that there's any burning going on at all? I believe the light from a fire is not directly emitted by the chemical reaction, it's a result of the combustion gasses glowing from the heat. In which case just heating even an inert gas sufficiently will cause it to glow similarly. And the immense high-speed compression from a mach-7 projectile traveling down a confined tube should generate plenty of heat.
--- Most topics have many sides worth arguing, allow me to take one opposite you.
So we're back to throwing rocks.
We just throw them very, very fast. :)
I do not fail; I succeed at finding out what does not work.
Perhaps one of the big benefits of a naval railgun is that it's so difficult to defend against. Old-fashioned anti-ship missiles can be disabled or destroyed by the defending ship's close-in defenses. This is because the incoming missile is filled with sensitive electronics, guidance systems, explosives, fuel, turbojet engines, stabilizing fins, etc, and is very likely to be damaged or destroyed if hit by a 20mm round from the defending ship's CIWS missile defenses.
However, how do you shoot down a hunk of metal traveling at mach 7 toward your ship? It wouldn't make any difference if you hit it with a 20mm round from the goalkeeper or phalanx. The projectile would just keep flying toward the ship and strike it anyways. Besides, how would you even hit something which is so small and traveling at mach 7.
It doesn't seem there would be any good defense against this.
"Flame" is nothing but superheated gases. You can have a flame without combustion if you raise the temperature some other way. In this case it's electrical heating, ram air pressure, and simple air friction.
Many!
Imagine if you didn't need to handle explosives like Cordite as propellents anymore. This will reduce storage space and make a battleship's gun turret a while lot safer place to work. One small spark won't set off a magazine anymore.
"Muzzle velocity" is higher, so the distance you can throw something is a bit further, like 5x further. If you can fire further, you have a huge advantage because you can hit your opponent before he can shoot at you. Or if you are doing ground support, you can fire further inland.
I'm assuming a rail gun will be faster to reload. Might take some time to recharge the power supply, but surely we can fire faster than a Mark 7's 2 rounds a minute. More pounds and rounds on the target than your opponent is always better.
Finally, it may be possible to more strictly control forces on the shell when firing it, which may make it possible to put more technology IN the shells, and still get very high velocity. Imagine a shell that can adjust it's flight path, even slightly, which means you can fire in the general direction you want, then fine tune the aim in flight. (I assume they don't do that now..)
Issues to watch out for: First, Rail guns tend to have tracks (rails) and said rails usually have difficulty with wear due to the huge forces and high speeds involved. Hopefully they have engineered the better materials. Second, power supplies for rail guns have to be designed to provide HUGE impulse powers with power generation systems wanting to be running at steady state. You have to match the two. Finally, weapons like this usually mean you have to redesign the whole weapons system, a process that literally takes decades.
Go Navy, this is worth the R&D money..
"File to fit, pound to insert, paint to match" - Aircraft Maintenance 101
Now we just need someone to say: "Yeah, bitch! Magnets!" and our Breaking Bad reference is done.
The range means you can fire it from beyond the horizon, so radar can never spot the firing. The speed means you have no way in hell of dodging it or shooting it down. And the kinetic energy of it means no armor will block it, short of armoring the ship to the point it can't move. Just take aim at the power plant or armory of the other ship and you get a guaranteed kill. I think the key advantage is the inability to be dodged or shot down like a shell, but the range of a missile. Also, I imagine detecting a missile launch is easier then detecting a railgun firing.
according to the experts at yahoo answers, there isn't recoil in the traditional sense, but there is recoil because physics and also it somehow forms babby.
23 lbs = 10.5 kg
Mach 7 = 5300 mph = 2382 m/s
KE = 0.5mv^2 = 59.6 MJ
The ship in question has four 9100 kW diesel engines (12,200 hp).
Assuming you have a big enough capacitor, the output from just one diesel engine should be enough to power a round every 6.5 seconds. There are conversion and efficiency losses, so probably every 15-20 seconds is more realistic.
Also note that 59.6 MJ is about equivalent to 14 kilos of TNT. So the energy yield of this will be on the order of a high explosive round from a 5 inch shell (which weighs about 30 kg), assuming the projectile doesn't pass entirely through the target.
Not exactly. Oxygen is a prerequisite for the process known as combustion, since combustion is an oxidization reaction. "A rapid, exothermic oxidation of a substance, called the fuel," is a reasonable definition of combustion. Usually we say the fuel is combustible.
The road to tyranny has always been paved with claims of necessity.
It's an inert piece of metal that can't be jammed and is probably hard to spot on radar too.
IAAP, although not an expert in rail guns or radar.
I would guess that the projectiles would be hard to detect on radar because they're small. However, it would seem to me that the rail gun itself would send out one hell of a large EMP that would reveal the location of the gun and the time of firing.
If it weren't for deadlines, nothing would be late.
Smaller diameter projectiles have more drag per unit mass and slow down faster due to air resistance. It's called their ballistic coefficient.
The practice for howitzer-like weapons like railguns is to fire their projectiles in a high arc to get them out of thick atmosphere as fast as possible to reduce air friction. They still won't hit their target at anything like their muzzle velocity even after they recover some kinetic energy on the way back down to target from the top of their parabolic arc.
The ballistically efficient shells from the late-model 15" US Naval rifles had a muzzle velocity of about 3500 feet/second and a flight time to target at maximum range (25 miles or so) of a couple of minutes. Their velocity at impact was half that of their muzzle velocity. I don't see these railgun projectiles achieving anything like that performance as drag increases roughly as the square of velocity and their ballistic coefficient will be a lot less.
Oxygen, it's in the air...
fine vaporized particles of metal...
*poof*
And that, ladies and gentlemen, is a demonstration of what we science nerds like to call 'simple science for senators". The amazing thing about it is that you can actually get billions of dollars in funding using this simplified approach when brilliantly researched and written scientific papers fail miserably. Go figure!?!?
Only to idiots, are orders laws.
-- Henning von Tresckow