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Us Navy's New Railgun Zaps Old Record

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US Navy's New Railgun Zaps Old Record

A railgun is the stuff of science-fiction and video games. Instead of firing an explosively fired projectile, a railgun uses an electromagnetic current to accelerate a non-explosive bullet to several times the speed of sound. On Friday, at 11 AM today, the Navy set a record, by producing a 33-megajoule firing, more than three times the previous record it set in 2008.

Rear Adm. Nevin Carr, chief of naval research, said in a Navy report on the test:

"The 33-megajoule shot means the Navy can fire projectiles at least 110 nautical miles, placing sailors and Marines at a safe standoff distance and out of harm's way, and the high velocities achievable are tactically relevant for air and missile defense. This demonstration moves us one day closer to getting this advanced capability to sea."

Compare that distance with the capabilities of the Iowa-class battleships, the last great battleships of the U.S. Navy. These could hurl an armor-piercing shell 24.06 miles.

Friday's test was run at the Naval Surface Warfare Center in Dahlgren, VA, the same place where the prior record was set. Without the need for explosives to propel the shells, life on a Navy ship would be a lot safer. The Navy still many issues to overcome. However, the Navy expects fully functional railguns on the decks of U.S. Navy ships in the 2025 timeframe.

Wild stuff.

Japan had the biggest naval guns in WWII, 18.1" x 1463kg shells from her Yamamoto class ships. These big guns were also contravening the agreements of the day, and were the biggest ever made for any navy, ever.

To put it into perspective, those Japanese guns were lobbing around big shells using 440 megajoules of energy, at around 780 m/s, but that rail gun is sending out a 12kg projectile at 2,400 m/s.

Crazy sh1t.

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US Navy's New Railgun Zaps Old Record

Wild stuff.

Japan had the biggest naval guns in WWII, 18.1" x 1463kg shells from her Yamamoto class ships. These big guns were also contravening the agreements of the day, and were the biggest ever made for any navy, ever.

To put it into perspective, those Japanese guns were lobbing around big shells using 440 megajoules of energy, at around 780 m/s, but that rail gun is sending out a 12kg projectile at 2,400 m/s.

Crazy sh1t.

Pedant time - It was the Yamoto (meaning literally 'Japan') Battleship. Yamamoto was the Admiral who devised the Pearl Harbour and Midway raids.

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Wild stuff.

Japan had the biggest naval guns in WWII, 18.1" x 1463kg shells from her Yamamoto class ships. These big guns were also contravening the agreements of the day, and were the biggest ever made for any navy, ever.

To put it into perspective, those Japanese guns were lobbing around big shells using 440 megajoules of energy, at around 780 m/s, but that rail gun is sending out a 12kg projectile at 2,400 m/s.

Crazy sh1t.

Earth escape velocity is circa 11.2km/s.

IMO, the building of railguns for space launch is one of the best ways to try and continue space exploration. They are not suitable for humans, what with the whole 'reduced to red paste' issue, but for bulk delivery - food, fuel, water, basic construction kit - there is no problem. This means that, for example, you could build a decent sized space station with a small number of expensive rocket launches and a large number of cheap railgun shells. And then the space station itself could act as a manifactury for spaceships for ongoing exploration.

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Pedant time - It was the Yamoto (meaning literally 'Japan') Battleship. Yamamoto was the Admiral who devised the Pearl Harbour and Midway raids.

You are correct, and I often make that mistake.

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US Navy's New Railgun Zaps Old Record

Wild stuff.

Japan had the biggest naval guns in WWII, 18.1" x 1463kg shells from her Yamamoto class ships. These big guns were also contravening the agreements of the day, and were the biggest ever made for any navy, ever.

To put it into perspective, those Japanese guns were lobbing around big shells using 440 megajoules of energy, at around 780 m/s, but that rail gun is sending out a 12kg projectile at 2,400 m/s.

Crazy sh1t.

I want one!

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Earth escape velocity is circa 11.2km/s.

IMO, the building of railguns for space launch is one of the best ways to try and continue space exploration. They are not suitable for humans, what with the whole 'reduced to red paste' issue, but for bulk delivery - food, fuel, water, basic construction kit - there is no problem. This means that, for example, you could build a decent sized space station with a small number of expensive rocket launches and a large number of cheap railgun shells. And then the space station itself could act as a manifactury for spaceships for ongoing exploration.

Would the food and delicate electronics not alo get reduced to mush? There must be something in it because that's what Gerald Bull was working on in between designing Superguns for the sand people and bing assasinated by Mossad.

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Would the food and delicate electronics not alo get reduced to mush? There must be something in it because that's what Gerald Bull was working on in between designing Superguns for the sand people and bing assasinated by Mossad.

As long as the food starts out as mush it shouldn't be a problem. Or freeze-dried..

As for electronics, it depends - it should be OK if packaged correctly. Essentially, there would be some delicate things you need to put on a rocket, but not much. And if your bulk supplies are coming up in a regular stream, then there would be so much more space on the resupply rockets.

Of all the potential space-launch mechanisms that don't involve rockets, space guns are one of the few that could pretty much be built tomorrow, i.e. no major technical hurdles.

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If it doesn't use explosives, what was all that fire and smoke?

The gun self destrutcting. I will be impressed with anyone who makes a rail gun that can fire say, 100 rounds in a day. The projectile track and electromagnets get hammered in a rail gun.

I think they're also pretty pointless as a "big gun". Essentially you're trading mass for speed. Sounds good from the point of view of KE = 1/2 mv^2, but speed degrades very rapidly in the atmosphere, you lose a lot of it very quickly. If you're lobbing shells over the horizon, you need some sort of parabola, and the idea is to drop a great big lump of explosive into a deck. The damage is caused by the thing exploding, not so much the kinetic energy. As a rapid fire, line of sight weapon it would be cool, but the engineering would be very hard.

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As long as the food starts out as mush it shouldn't be a problem. Or freeze-dried..

Tomato puree would be ideal. That would solve the 'reduced to red paste' problem.

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Earth escape velocity is circa 11.2km/s.

IMO, the building of railguns for space launch is one of the best ways to try and continue space exploration. They are not suitable for humans, what with the whole 'reduced to red paste' issue, but for bulk delivery - food, fuel, water, basic construction kit - there is no problem. This means that, for example, you could build a decent sized space station with a small number of expensive rocket launches and a large number of cheap railgun shells. And then the space station itself could act as a manifactury for spaceships for ongoing exploration.

It is not an easy task, first and foremost you would burn up the bullet/pellet you fire at >11.2km/s and secondly the speed would need to be greater than that because of the atmosphere

Think of the space shuttle re-entering earth and how hot that gets. It does that at a fairly modest 6km/s but that is at a point where the atmosphere is very thin. You need to fire it at probably some 20km/s and where the atmosphere is very thick. I suspect you would melt whatever material you use.

As for rail guns as weapons. What is the point? What can they do above what the military has today?

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It is not an easy task, first and foremost you would burn up the bullet/pellet you fire at >11.2km/s and secondly the speed would need to be greater than that because of the atmosphere

Think of the space shuttle re-entering earth and how hot that gets. It does that at a fairly modest 6km/s but that is at a point where the atmosphere is very thin. You need to fire it at probably some 20km/s and where the atmosphere is very thick. I suspect you would melt whatever material you use.

As for rail guns as weapons. What is the point? What can they do above what the military has today?

Actually, the hight record is apparently circa 100 miles, and the shell didn't burn up. But the main trick to avoid friction burnup and speed loss is to make sure that your gun muzzle is at an altitude of >5km, ideally more, so that the majority of the atmosphere is bypassed. There is no particular engineering issue with, for example, a 16km high tower, which would take 90% of the atmosphere out of the equation. Compared to many space rocket programs, the cost would be cheap.

I think that the military application is in base/ship defense - because these things shoot such fast projectiles, it is much easier to hit things like incoming missiles; corrections for target movement, gravity and wind are that much smaller.

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I think that the military application is in base/ship defense - because these things shoot such fast projectiles, it is much easier to hit things like incoming missiles; corrections for target movement, gravity and wind are that much smaller.

Would they have any advantages over lasers for missile defence?

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Er - clouds and the horizon(for skimmers) don't get in the way?

Clouds perhaps, if there are enough of them, but the horizon in the way is equally as much trouble for using a railgun to intercept missiles - if it's far enough away to be below the horizin I'll be amazed if you'll be able to fire any ballistic projectile accurately enough to hit a missile, whatever the launching system.

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Would they have any advantages over lasers for missile defence?

Probably that hard kill systems would not be useful against them as the energy contained in the projectile would be so immense that even multiple hits won't deflect the projectile.

http://mythbustersresults.com/episode95

Just to stop a small 9mm bullet they needed an incredible number of magnets and only got it to move very slightly. I'd imagine that a hard kill 20mm round would be like a person trying to stop a train.

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It is not an easy task, first and foremost you would burn up the bullet/pellet you fire at >11.2km/s and secondly the speed would need to be greater than that because of the atmosphere

Think of the space shuttle re-entering earth and how hot that gets. It does that at a fairly modest 6km/s but that is at a point where the atmosphere is very thin. You need to fire it at probably some 20km/s and where the atmosphere is very thick. I suspect you would melt whatever material you use.

As for rail guns as weapons. What is the point? What can they do above what the military has today?

No it wouldn't burn, it's only exposed to the atmosphere for about 2 seconds at that speed to be well out of the troposphere, you could make it of aluminium. All you have to ensure is that thermal mass and conductivity of the missile is adequate to absorb the friction energy. The shuttle is deccelerating, so it spends a lot longer in the atmosphere turning it's kinetic energy to heat which it has to dissipate radiatively, thus it's need for the ablative tiles.

As for payloads, aircraft flight recorders are rated to 3,400G and 1,000C. I have used quite standard relays rated at over 3,800 G. Might make a mess of the egg sandwiches though.

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Actually, the hight record is apparently circa 100 miles, and the shell didn't burn up. But the main trick to avoid friction burnup and speed loss is to make sure that your gun muzzle is at an altitude of >5km, ideally more, so that the majority of the atmosphere is bypassed. There is no particular engineering issue with, for example, a 16km high tower, which would take 90% of the atmosphere out of the equation. Compared to many space rocket programs, the cost would be cheap.

It is not so much the amount of atmosphere but the density at the point you shoot it out at 20km/s

I think that the military application is in base/ship defense - because these things shoot such fast projectiles, it is much easier to hit things like incoming missiles; corrections for target movement, gravity and wind are that much smaller.

why not just fire 1000 bullets/sec if your unsure you will hit it?

i doubt these things would be more accurate than a computer controled missile or gun.

the fact is these thing add nothing new to what we have today

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No it wouldn't burn, it's only exposed to the atmosphere for about 2 seconds at that speed to be well out of the troposphere, you could make it of aluminium. All you have to ensure is that thermal mass and conductivity of the missile is adequate to absorb the friction energy. The shuttle is deccelerating, so it spends a lot longer in the atmosphere turning it's kinetic energy to heat which it has to dissipate radiatively, thus it's need for the ablative tiles.

As for payloads, aircraft flight recorders are rated to 3,400G and 1,000C. I have used quite standard relays rated at over 3,800 G. Might make a mess of the egg sandwiches though.

Humm good point but I am still unconvinced

A 1 tonne projectile made of steel would heat up to 12,000 centigrade well above its melting point if friction dropped its speed from 13km/s to 12.5km/s.

Hell your probably looking at a speed loss of 1% to melt the thing. Not done the math but as a guess it would lose that much speed

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But the main trick to avoid friction burnup and speed loss is to make sure that your gun muzzle is at an altitude of >5km, ideally more, so that the majority of the atmosphere is bypassed. There is no particular engineering issue with, for example, a 16km high tower, which would take 90% of the atmosphere out of the equation.

This was the idea behind "super guns" that the Iraqi's were building - a very long barrel that allowed slow acceleration of a projectile to am immense speed, thus giving them greater range. The physics works fine, the engineering is tough. Building a 16 km tower is possible, building it around a straight and strong gun barrel would be pretty tough. In high winds, big buildings move around far too much to support a gun barrel.

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This was the idea behind "super guns" that the Iraqi's were building - a very long barrel that allowed slow acceleration of a projectile to am immense speed, thus giving them greater range. The physics works fine, the engineering is tough. Building a 16 km tower is possible, building it around a straight and strong gun barrel would be pretty tough. In high winds, big buildings move around far too much to support a gun barrel.

That didn't turn out very well for Gerald Bull.

Creating weapons is a dangerous game when you aren't hidden away in some state bunker.

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Probably that hard kill systems would not be useful against them as the energy contained in the projectile would be so immense that even multiple hits won't deflect the projectile.

http://mythbustersresults.com/episode95

Just to stop a small 9mm bullet they needed an incredible number of magnets and only got it to move very slightly. I'd imagine that a hard kill 20mm round would be like a person trying to stop a train.

Interesting that. When you are talking about magnets deflecting bullets, I'd have to ask as to why you would ever bother testing it as magnets only affect ferrous metals and bullets are made of non-ferrous metals - copper and lead usually. Some use steel jackets instead of copper but not commonly.

The bit about not being able to ignite flammable products is interesating but this was demonstrated over 20 years ago in a police & military instructional video called "Deadly Weapons". They fired several bullets into petrol tanks without igniting them, including tracer bullets. I think they actually got it to explode by raping a stick of Dynamite to the tanl or something equally ludicrous. Everyone assumes that sparks created by the bullet hitting the tank ignites the fuel but, again, you only get sparks with ferrous metals.

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  • 312 Brexit, House prices and Summer 2020

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      • down 5% +
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