Navy's Railgun 'Faster Than a Speeding Bullet'

[MaineCWPtraining]

Navy Sets World Record With Incredible, Sci-Fi Weapon

December 10, 2010


U.S. Navy engineers at the Office of Naval Research prepared and test-fired a slug from their rail gun in a 2008 test firing. On Friday, December 9, the ONR will attempt to break its own record.

A theoretical dream for decades, the railgun is unlike any other weapon used in warfare. And it's quite real too, as the U.S. Navy has proven in a record-setting test today in Dahlgren, VA.

Rather than relying on a explosion to fire a projectile, the technology uses an electomagnetic current to accelerate a non-explosive bullet at several times the speed of sound. The conductive projectile zips along a set of electrically charged parallel rails and out of the barrel at speeds up to Mach 7.

The result: a weapon that can hit a target 100 miles or more away within minutes.

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[Boghog1]

Mach 7? holy poop that is fast

To bring some perspective, 2500 meters/second is 1.553 miles per second or 5,591 mph. That is 8200 feet per second. Compare that to a high powered rifle at 3200-3600 f/s. Most jet fighters have a speed limit below Mach 2. Escape velocity from the earth's gravitational field is about 6.95 miles per second (25,000 mph) or 11,200 meters per second.

http://www.militarytimes.com/multimedia/video/?bcrefid=013108railgun

 

[syntax]

super cool, but Blitz beat ya to it here:
http://www.northeastshooters.com/vbulletin/threads/117101-Navy-Going-For-A-World-Record...Rail-Gun.

 

[ARowley]

AMAZING TECHNOLOGY

I'll take one in Pre-ban please.

 

[italianppf2]

super cool, but Blitz beat ya to it here:
http://www.northeastshooters.com/vbulletin/threads/117101-Navy-Going-For-A-World-Record...Rail-Gun.

that's because Blitz is the man, yo!

 

[MisterHappy]

Cool tech, poorly written article....

One thing I don't get: it leaves at Mach 7, from that point on it decelerates. Since all the energy is kinetic, the terminal ballistics is the thing. I don't see how at the stated maximum range of 100 miles it would have that much speed (relatively speaking) and without the speed, since it's not a huge, heavy object (didn't notice the mass in the article) there won't be that much energy delivered.

Considering that even the 16-inch guns on teh battlwagons still used explosives to get the job done at range, I don't see how this is going to me that effective in terms of damage.

Now, at "closer" range (say a few miles) the projectile would still be quite zippy, and would pack a punch.

With all the research with armed drones, this sort of energy-intensive weapons system seems a bit superfluous.

 

[strangenh]

One thing I don't get: it leaves at Mach 7, from that point on it decelerates. Since all the energy is kinetic, the terminal ballistics is the thing. I don't see how at the stated maximum range of 100 miles it would have that much speed (relatively speaking) and without the speed, since it's not a huge, heavy object (didn't notice the mass in the article) there won't be that much energy delivered.

Good questions. Info on the prototypes at University of Texas were online for a while something like 8 years ago. The prototype systems had a sustained 3-5 rounds per second rate of fire. That rather changes things, even at 100 miles, since with over 5 rounds/sec, it would still be a serious anti-aircraft weapon at that range. And these systems only get better. Imagine the rate of fire now! At closer ranges, these systems could probably write "GO AWAY" through the hull of an enemy ship.

 

[Dexion1619]

Forgive me if this is way off base, but wouldn't this work much like an arrow on a ballistic arc at long range? If I remember correctly, an arrow fired at a roughly 40-45% arc comes back down at something like 70% of its launched velocity. 70% of Mach 7 is still going to lay a world of hurt on whatever it hits. (I know wind resistance would effect this).

 

[MisterHappy]

Forgive me if this is way off base, but wouldn't this work much like an arrow on a ballistic arc at long range? If I remember correctly, an arrow fired at a roughly 40-45% arc comes back down at something like 70% of its launched velocity. 70% of Mach 7 is still going to lay a world of hurt on whatever it hits. (I know wind resistance would effect this).

Not an aeronautical engineer, or a physicist, but the resistance of the air to a moving object is not simple. Absent air resistance, an object thrown up will come back down with the same sped at which it was launched. A bullet fired straight up at, say, 2500fps will not impact with the same speed.

I'd say that a supersonic item will slow down quite a bit....still...cool.

 

[n1zfg]

When they start doing really long range ballistics, they tend to start firing it a lot closer to vertical to take advantage of the lack of air (and its resistance) at high altitude.







"We'll throw rocks at them"

-- Mycroft, in "The Moon Is A Harsh Mistress"

 

[Andy in NH]

LiveLeak has a video of the test.

 

[Baldkat82]

in the notes with the above video

The Navy still has a distance to go, however, before the railgun test becomes a working onboard weapon. Technically, Ellis says they've already overcome several hurdles. The guns themselves generate a terrific amount of heat -- enough to melt the rails inside the barrel -- and power -- enough to force the rails apart, destroying the gun and the barrel in the process.

The projectile is no cannon ball, either. At speeds well above the sound barrier, aerodynamics and special materials must be considered so that it isn't destroyed coming out of the barrel or by heat as it travels at such terrific speeds.

 

[Gammon]

The first time I heard of a "rail gun" it was suggested for use outside the Earth's atmosphere where drag would not be a factor.

 

[rattletrap1970]

I think regardless of the forward velocity and object still falls at 32 ft-sec^2 up to terminal velocity.
Let's say you dropped a bullet from 4 feet off the ground and it took "X" time to fall.
Now you fired a bullet from a gun at 5280 ft-sec with a LEVEL barrel; the bullet from that barrel would still take the same "X" time to hit the ground (although a lot farther away) if you start the clock at the moment the bullet leaves the barrel. Time of travel equals drop, if that thing gets a projectile moving at Mach 7 then it's not going to drop much in and bring a lot of KE with it. Some kid did a lot of research on this technology in his garage. Couldn't get an accurate chronograph readings cause of the EMP the rail gun made.

 

[Spanz]

I think the benefit of such weapons might be close-in targets, like exocet or chinese missiles skimming across the sea trying to take out an aircraft carrier. They need to fire something at hypervelocity to get to the target before it has time to jink left or right. The fact that the velocity will die out as the range increases is not that big of a problem, as you might not even be able to see such missiles more than a few miles out. Maybe something to replace the brute-force Phalanx system.

 

[Skysoldier]

I want some of those capacitors in that video!

 

[SheepDog_B]

Weapons improve and cost less taxpayer money, gotta love it!

 

[vellnueve]

They need to fire something at hypervelocity to get to the target before it has time to jink left or right.

I wasn't aware that missiles are able to react to incoming fire on their own. I know they can be programmed to perform certain maneuvers (like the pop-up maneuver) but I wasn't aware that they can see and avoid incoming fire.

The fact that the velocity will die out as the range increases is not that big of a problem, as you might not even be able to see such missiles more than a few miles out. Maybe something to replace the brute-force Phalanx system.

The velocity isn't going to bleed off nearly as much as people think.

 

[DustinK]

Good questions. Info on the prototypes at University of Texas were online for a while something like 8 years ago. The prototype systems had a sustained 3-5 rounds per second rate of fire. That rather changes things, even at 100 miles, since with over 5 rounds/sec, it would still be a serious anti-aircraft weapon at that range. And these systems only get better. Imagine the rate of fire now! At closer ranges, these systems could probably write "GO AWAY" through the hull of an enemy ship.

The article stated that they were hoping to achieve 6-12 rounds per MINUTE but are not yet there so I wouldn't count on ROF being a major selling point just yet.

 

[strangenh]

The article stated that they were hoping to achieve 6-12 rounds per MINUTE but are not yet there so I wouldn't count on ROF being a major selling point just yet.

These tests are of massively more powerful weapons than the prototypes I was talking about. The UT Austin high ROF was for weapons delivering about 9 MJ... almost 10 years ago. (2kg projectiles at 3 km/sec)

 

[mostly_lurking]

in the notes with the above video

The Navy still has a distance to go, however, before the railgun test becomes a working onboard weapon. Technically, Ellis says they've already overcome several hurdles. The guns themselves generate a terrific amount of heat -- enough to melt the rails inside the barrel -- and power -- enough to force the rails apart, destroying the gun and the barrel in the process.

The projectile is no cannon ball, either. At speeds well above the sound barrier, aerodynamics and special materials must be considered so that it isn't destroyed coming out of the barrel or by heat as it travels at such terrific speeds.

Keep in mind that the temperature rise ratio across a normal shock at M=7 is about 10.5. Given a 70°F day is 530°R, the temperature at the tip of the projectile is 10.5 X 530 =5565°R = 5105°F. Well above the melting point of most alloys, and about 1000° hotter than the center of the plume of a jet engine with the afterburner on.

True, it won't be a normal shock in front of it but an attached oblique, the temperature rise is still large.

 

[italianppf2]

This thing is Sickkkkk!

 

[enbloc]

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