Navy's New Railgun Shoots at Mach 7, Can Hit Targets 100 Miles Away

By Jennifer Welsh | December 13, 2010 3:58 pm

Last week the Navy took its best shot–and it was a doozy. The shot, fired on December 10th, broke the world record for the most powerful shot, as the 23-pound aluminum projectile rocketed out of the Navy’s electromagnetic railgun at a reported speed of Mach 7, or seven times the speed of sound.

Today’s 33-megajoule shot–powerful enough to launch 33 Smart cars at 100 mph–means the Navy can fire projectiles at least 125 miles, keeping military personnel at a safe distance from their targets, according to the Office of Naval Research. [Popular Science]

Normal guns use explosions to propel bullets, but railguns use electromagnetic currents to accelerate conductive bullets along two parallel rails. The Navy has been working on this project since 2005. The new test of the gun broke the Navy’s previous 10-megajoule record for railgun firing set in 2008.

“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,” [Rear Adm. Nevin Carr] added. “This demonstration moves us one day closer to getting this advanced capability to sea.” [Navy press release]

One of the project’s goals is to reduce the need to carry gunpowder and other explosives on Navy ships, making them less vulnerable. The big barriers to implementation now include figuring out how to power the gun off of a ship’s batteries, and how to protect the gun parts themselves from the incredible energy released when it’s fired.

The eventual goal is a ship-mounted railgun that can fire a projectile more than 200 miles at speeds of more than 8,000 feet per second. A kinetic energy warhead would eliminate the use of hazardous explosives on ships and on the battlefield, the Navy says. [Popular Science]

To reach those distances and speeds, the Navy will need to develop a  railgun that can shoot at 64 megajoules. Navy researchers hope to reach that goal and have a gun ready for on-ship use in 2025.

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Video: YouTube / usnavyresearch

CATEGORIZED UNDER: Physics & Math, Technology
  • Daniel J. Andrews

    I’m impressed that they were able to have the camera pan fast enough to track the projectile. That alone must have been a project in itself.

  • Douglas Watts

    Yay !!! More expensive ways to kill more people, please !!!

  • MT-LA

    @Daniel (#1): I was really surprised by that camera pan too. But there’s something a little too “perfect” about it. I mean, how do you go from 0 degrees/second to ALOT deg/sec with no acceleration time. It goes from standstill to full turning rate instantly (it seems).

    This is just a guess, but could it be that this was a panorama scene shot with super slow motion and just edited to look like it was a panning camera? Just a thought.

    Also, what’s with the “explosion” inside the chamber? Is that air just combusting because of the extreme pressure wave ahead of the projectile?

  • rabidmob

    I’m surprised they’re showing this off, it’s really cool though.

  • LM

    @MT-LA & Daniel: The method for capturing a projectile in flight like that involves a rotating mirror, the camera itself is stationary. The specific product is likely a DRS Flight Follower or similar product.

    The fact that it still was not able to keep up is a testament to the speed of the projectile.

  • Dean

    60 mega joules is alot!!!

    And that is a net 66. The best generators (efficiency) may hit 40% thermally efficient. Cables, resistance, transformers?, capacitors,,, holy wah ! Afraid of gunpowder? The ship will be half generator and half capacitor,,,,, and terribly sensitive to salt water. And the magnetic tides ? Fillings in your teeth, calcium in your bones?

    How about hydrogen in your water. Hydrogen IS a metal.

    And indefensible. One single 300 gram, aluminum clad, enriched uranium, fired from similar at close range, 10 or 20 miles, would pierce and short circuit the whole thing. And the short circuit would perhaps kill everyone and leave the ship largely intact?

    Hmmm. Gunpowder sounds better all the time.

    Robust ?

  • Wil

    The real trick isn’t firing a projectile at super high velocity, although that is nothing to sneeze at. The real challenge is doing it without destroying the projectile or melting or otherwise destroying the rail gun.

    Admiral Carr, let’s not exaggerate. When you can fire ANY big rail gun 10 times in 10 minutes, then you’ll actually have a weapon. Until then, its just a loud science fair project.

    By the way, I’d pay good money to see 33 Smart cars launched out of a cannon, or see a big cannon obliterate 33 Smart cars. Or even see 33 Smart cars drive off a cliff, while being shot at.

  • Georg

    I have the impression,
    they calculated the theoretical distance of the shot
    in a vacuum.
    In practice, aluminium “rounds” are optimal useless for
    achieving “dictance” and some power to the target.
    For both goals one needs maximum mass per cross section.
    (usually tungsten or uranium projectiles are used)

  • Florida_kes

    The problem for the Navy is that they are making a weapon that’s going to make surface ships obsolete! LOL!!!

    Can’t really defend an air craft carrier against a toaster flying in at MACH 8.

    Or as they built the A-10 around it’s 30mm, they can build a submarine around a rail gun. That will ruin any carrier task force’s whole day!

  • s

    LOL at Will

    You stole my thunder….I too would like to see 100 smart cars go zinging through the air.

  • Sajanas

    They had cameras that could catch nuclear explosions in the very early stages of their firing way back in the 1960s, it its not too surprising that they can have nice high speed color ones now. Still, great shot, and I loved all the fire that comes from it.
    So, does the nuclear reactor on a ship put out enough power to fire one of these guys regularly? Or are we going to have a Wave Motion Gun situation where you fire one shot, and wait on low power for a recharge.

  • Brian Too

    Does anyone really need this? Are conventional large ships guns such a big disappointment? Not that I know of.

    Besides, I thought that rocket munitions systems were heavily favored these days. Wouldn’t these have more range and controlability than a rail gun?

  • ohwilleke

    A little late. There is no ship even seriously in a design phase to use it.

    The original plan had been to include the railgun as the defining element of the Zumwalt class destroyer, one of the most expensive surface combatants ever designed at $3.3 billion each for three ships, which was designed with an Integrated Power System that would allow electricity generated to drive the ship’s engines to be momentarily diverted to power the railgun. But, it wasn’t functional soon enough, so they had to substitute a more conventional array of weapons: the usual collection of cruise missiles, two 155mm (i.e 6″) naval guns (the “Advanced Gun System”) and 2 57mm naval guns.

    The 23 pound projectile tested is about the same size as the warhead on the advanced gun system, but eliminates the need for 200 pounds of propellant, thus allowing the ship to carry more ammunition with less weight, and reducing the cost of ammunition (missiles can cost tens of thousands of dollars each, conventional artillery rounds cost in the low single digit thousands of dollars each, a railgun round might cost as little as hundreds of dollars each).

    A railgun wouldn’t add much to capabilities of the navy against large warships, for which missiles pack equal or greater punch with more accuracy at longer ranges, but would greatly improve the capacity of naval ships to deal with large numbers of armed speedboats or missile boats in an affordable way from beyond line of sight – something that is now a gap in U.S. naval capabilities.

  • s.sanders

    I understand how a magnetic field can accelerate a metal that can be magnetized, but aluminum is not such a metal. Something’s missing here.


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