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...
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.
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?
think of the horror of having shells fired at you and cant see a ship in sight
i love it
At the "alleged" speed there would be no fire, just Plasma like the shuttle. Those flames are not caused by friction. As you can clearly see the flames are expanding almost as fast as the projectile. So the projectile is not going anywhere near as fast as they claim. This appears to be yet another example of a private contractor bilking the military out of our tax money.
Bring on the nuclear powered battleship with a bank of these!
the 32 Megajoule gun is only half power, can't wait till the full size ones are on a new class of ship. Hope no one has it in their mind to attack us when we have these. Just lower the guns and fire, although my question is, any recoil?
Proud Sailor of the USN
This not only makes a great gun. You can also throw projectiles with a package inside up into orbit, for a space hotel, etc. I can see food to order being shot up to a space station restaurant.
As far as a navy is concerned, 2 shells moving 5,000 mph that weigh only 10 pounds, fired at the water line of a 500 footer, and that ship is sinking. If you have 4 rounds aimed at a target, it would desegregate it. No conventional ship bow could withstand 4 30 million Jules fired into it, even if the armor were 10 feet thick. And it can't be that thick, because it would not float.
But the very best part is the 200 mile range. They can sit in a minor sea lane and hit every major population zone in the area to devastating effect, especially if parked in international waters. Most cities are within 200 miles of the coast. No need to send in the planes, and no need for tactical nuclear weapons. A plane has limited ammo, but a rail gun can throw projectiles in a target area for days, until a bunker cracks, a small city is pounded to dust, or a mountain is sawed in half.
And it is very hard to determine the origin of the projectiles since nobody can see them coming in. Buildings just start collapsing and burning, as if a bomb were lit from inside. In seconds, an entire street of buildings could disappear with no overpressure effects. It would be very unnerving. America will be able to keep their military edge.
I am rubbing my chin curiously rather than skeptically.
I was on a different rail gun program back in the late 80's and never saw that much in the form of residual combustion. Vapor trails,yes. Combustion, no. To be fair, I was working with MUCH smaller( less than .350 inch) diameter projectiles at a much smaller shot.
That being said, the theory of the fragmentation of the shell is possible, but has holes in it. I would offer the theory that the combustion is actually caused by the hydrogen in the ambiant air being dissoiated from the oxygen molecules. Addition of the drag and friction of the projectile (possibly coupled with the burning fragments of the projectile proper)could cause ignition of the combustible and the oxidizer.
Then again, it could be artificial propulsion in this particular video. Its too few angles and too short in duration for me to hang my hat on it.
Sorry guys, but the video is slightly out of order... the first shot is of the impact. If you pause the video around 6-7 seconds you can see the projectile only has a plasma trail until it strikes the target. It appears that the massive fireball is from the target since only shows after impact during the previously mentioned time on the vid. Just thought I would point that out. Thanks.
Anyone thought of using one of these to fire planes? With one of these shooting at escape velocity, it would make a great replacement for the shuttle. And since it will probably use no fuel, it would be great for bringing more equipment up. My only concern is the g-force at that speed. It would kill you, and there would probably be nothing left.
eht emalf si lamron enim seod eht emas
It doesn't take a genius to see that this isn't solely powered by magnets. The first shot in the video clearly shows a trail behind the projectile. It's also got fins at the back and the projectile itself is big enough to store a small amount of fuel. When it hits the wall, it burts into flames, i.e the fuel explodes on impact. If it's going to burning anything up during flight, it would be burning the air up in front of it, however the video shows no signs of this.
Following in the footsteps of Popsci's most annoying and overused word, I declare you WRONG!
AT nothanks. It does take a genius to know what you just said is total BS. The trail behind the projectile is plasma its whats happens when something moves that fast the air behind it is heated to plasma and a object moving that fast would travel faster than the plasma. Oh and the fins are just for stabilization and they are not big enough to hold enough fuel to make the projectile go and faster.
So following in the footsteps of your most annoying and recently used words,
I declare you wrong!
04/10/08 at 9:15 am
If it's going so fast, how did they videorecord it and still have it look so good?
High speed high definition cameras operating with frame rates up in the million per second.
"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."
You are correct - you are not an engineer. Or a geologist.
Your error lies in the assumption that no stone can burst into flame when struck by a purpose-designed projectile with a very narrow point of contact moving at Mach 5.
'Stone' isn't necessarily comprised of only one non-flammable mineral. Think shale.
200 miles? 4000 mph? This is a primitive device given our rockets, capable of guidance, reach escape velocity (25000 mph) to leave the planet. It would be smarter to load projectiles onto spacecraft and utilize gravity well accelerations to increase speed for free, keeping as many coming over the horizon as our peace time economy can lift. Then, thruster target incoming bullets from space. No ships, no limits, no nukes, lower cost.
As we are occasionally still commenting on this one, the flames; as drozzle said, are actually the plasma that was air until the explosive expansion of the high speed projectile moving through it occurred. Everything in that immediate vicinity becomes involved with the electron configuration as all that charge seeks it's lowest available state. It would be more surprising if there were no flame when used in our atmo. The three most plentiful ingredients all burn easily.