But what's with all that fire?

Um, wow. This video comes from a test firing of the Navy’s Elecromagnetic Railgun (EMRG), which was carried out yesterday at the Naval Surface Warfare Center in Dahlgren, Virginia. The gun—which generates a powerful electromagnetic field to hurl projectiles at extremely high speeds—is rated at 32 megajoules, but the railgun engineers have to work up to that number slowly: this test was designed to reach a record-setting muzzle energy rating of 10 MJ. (The actual number turned out to be 10.64 MJ, according to Collin Babb with the Office of Naval Research.)

One big question this video begs is, what causes the giant fireball? Rail guns are supposed to be powered solely by electricity, and don't use explosives of any kind for propellant. Babb told PopSci the answer: The flames are from pieces of the projectile disintegrating; the 7-pound slug is jammed so firmly between the rails that when it’s fired, pieces shear off and ignite in the air. There’s been some speculation online that the flames come from some sort of gas that’s been used to increase conductivity. Wrong: The EMRG uses no secondary propellant — just electricity. As a result, the breech can remain open during firing and the gun produces no blowback whatsoever. In fact, the researchers sometimes place cameras and mirrors inside the breech during tests to get a better sense of what’s going on.

That flash from the projectile hitting its target is momentary, and the paper on the target isn’t burned at all afterward — just ripped and shredded from kinetic damage.

The Navy’s 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. Context: The Navy’s current MK 45 five-inch gun has a range of just 20 miles. The Navy hopes to have a prototype ready sometime between 2016 and 2018.


I'm no expert but it you pause the clip there is flame coming from the back of the projectile that looks like a rocket flame. you can only see it when the orange flame is gone

"Black holes are where god divided by zero"

even at the final operating speed of 28800000 Feet = 5454.72000 Miles per hour there is no reason for stone to burst into flame on impact. I am not an engineer or scientist how ever and could be wrong; but whole footage seems fishy to me.

"whole footage seems fishy to me"- 32 megajoules, 200 miles
Anyone who thinks that releasing that much energy isn't going to result in excess heat being released (ie stuff burning) either needs to go back to physics class or do a Wikipedia search on entropy. Air at that speed would burn most anything.

ok.... apparently no one here knows that much about the atmosphere... space shuttles use a heat shield so they dont burn up on reentry the arne moving nearly as fast as the projectile in this story and they are moving through a much thinner atmosphere at hugh altitude.... if the projectile WASN'T burning up would be the only reason to speculate

I don't really care what caused it. But...

LOL, Limewire
Seth the Giant

So how's about that huge EMP from the weapon firing? Seems like a waste of power considering the potential weight issues for sheilding that might be better spent loading conventional weapons aboard the ship.


from la vernia, tx

waste of what power? a bank of those would have like a .. nuclear power plant each. hmm new battleships anyone? 2 banks,3guns...2nuclear powerplants and you have a modern yamato....

What's a waste of power is the chemical propellant stored in the casings of idle artillery shells in conventional big guns, and this is the primary reason they have been phased out in favor of smaller, high-velocity gunds (see modern Destroyer's and the mothballing of the fire-support fleet of Battleships and Cruisers).

A conventional piece of artillery with an output comparable to this railgun (rated 32MJ) would require a massive artillery piece firing equally massive projectiles. Even the greatest big guns ever put to see ( the 400,000 pound Mark 7 16" guns) only put out about 20MJ of energy at the muzzle. This is a tremendous amount, to be sure, and it is compounded by the potential energy of the large volume of TNT stored in the 2,700 pound shell. Nonetheless, this railgun can accomplish a greater muzzle energy, a greater precision, a shorter time-on-target, a faster reload, and with an INFINITELY SMALLER LOGISTICAL FOOTPRINT. These things are extremely more practical. And let us remember that the Iowa class hit the "law of exponentials" practical energy barrier; increasing the size of the guns and destructive potential of its shells further required increasingly large volume investments for diminishing explosive returns. The Japanese Yamamoto-class super battleship had only a marginally more energetic main gun (approximately 5-10 percent increase) for a 25% increase in mass.

This is the future of warfare. It will make armor obsolete; tomorrow it will be all about speed, stealth, and accuracy. He who fires first will win. Big ships are a liability and a poor investment. The aircraft carrier, the last of the big ships, will need to be superbly well protected by standoff weapons (destroyers mounting their own railguns and long-rang missiles), high stealth, and great speed if they are to remain competitive.

If it's going so fast, how did they videorecord it and still have it look so good?

I seem to remember that Popular Science has run articles before on the rail gun. Mid 1980's, spoke of speeds of 8 miles per second. So, 8000 feet per second seems rather slow. My (Old Now) memory says that 7 miles per second for a 30 pound object is equal to escape velocity. With the advent of the radio shack model 3 computer, it was possible to control a switching mech quick enough to pull push a ball point pen (they were metal those days) to an interesting velocity. Enough to get it through a pine 2 x 4. I would have thought a modern projectile would be a plastic, boron fiber?

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