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Navy Tests Mach 8 Electromagnetic Railgun
hargrand writes "Wired magazine has a story and publicly released video of the Navy test firing of a 32 megajoule electromagnetic railgun: 'Reporters were invited to watch the test at the Dalghren Naval Surface Warfare Center. A tangle of two-inch thick coaxial cables hooked up to stacks of refrigerator-sized capacitors took five minutes to power juice into a gun the size of a schoolbus built in a warehouse. With a 1.5-million-ampere spark of light and a boom audible in a room 50 feet away, the bullet left the gun at a speed of Mach 8.'"
You'll finally dominate the USSR militarily, ending the Cold War.
I've heard that before "Rule Britannia, Brittania rules the waves...".
I'm still trying to get them kids off my lawn. But kids on bikes are quick, wily and seem to move in Brownian Motion tracks. Mach 8 could give me a good tactical advantage . . .
Schroedinger's Brexit: The UK is both in and out of the EU at the same time!
Mach 8 = 2 722.32 m/s.
Escape velocity being 11.2 km/s, so the answer is no.
- These characters were randomly selected.
You win again, gravity!
Escape velocity is the velocity required to leave orbit, not to maintain a stable orbit. Of course, low Earth orbit is about 8 km/s, so still no.
So if this is the future...where's my jet pack?
...I would be also interested to see what the projectile does at the "destination". Time to buy me some kilofarad supercaps :)
"The agriculture ministry is not in charge of Gundam" - Japanese ministry official.
If something is thrown or shot, the orbit will go through the point the shot was fired. You have a problem if that is on earth surface. Even if you are fast enough for a stable orbit you need a rocket to shift that orbit away from your starting point.
This might have been the ideal plot for a "survival" game for the 8-bit platforms. The mighty cannon takes 5 minutes to charge...the counter starting from 300 and dropping down...hordes of enemies crowding the cannon, some turrets or else controlled by the player which shoot down the enemies...I can even hear the frenzy music created by the oscillators of the C64 SID...Great plot, indeed.
Summary says the boom was audible in a room 50 feet away? If I tip over a chair, it's audible in a room 50 feet away...
lol even 50 yards would be ridiculous.
Hmmmm... The Washington Post article said Mach 5. In fact, it seemed more informative in general. http://www.washingtonpost.com/wp-dyn/content/article/2010/12/10/AR2010121007437.html
that is, ... almost as loud as dropping a frying pan. Very impressive.
At a deceleration of a constant 10m/s^2, it would still take 270 seconds to stop going up (the deceleration would actually decrease the higher it goes, but I'm not accounting for drag.. so its a tradeoff) it will have an average speed of 1.35km/s.
.. or throw some stuff up for the International Space Station to catch (347km altitude at perigee)
Thats 270s * 1.35km/s = a height of 364.5km, so it could conceivably enter into the region we call 'low earth orbit' which is between 160km to 2000km.
I dont know where to begin to calculate the drag as it rises, so I wont bother to calculate the decreasing deceleration either.
Might be able to shoot down satellites
"His name was James Damore."
Only one Quake2 reference, and none to Bayformers :(
I've got better things to do tonight than die.
The trick is to accelerate something that is a rocket to Mach 8 in a fraction of a second, and have it remain a rocket and not become an explosion...
I am TheRaven on Soylent News
While escape velocity could theoretically be achieved with a gun orbit cannot. This is because the orbit of a satellite will always pass through the point at which it ceased to be accelerated, which in this case is at the muzzle of the gun. You would have to add an orbital insertion rocket.
Warning: this article may contain humor, sarcasm, parody, and perhaps even irony. Read at your own risk.
The way I see it, there are several reasons why the USA would want to build Railguns:
- They have info that aliens exist and can come to Earth. - They have confirmation that someone (e.g. China, Iran, North Korea...) really plans to attack the Western World (or only the USA). - They are planning to conquer the World in the next 10-20 years. - Or they are really just being careful and making sure they can face the unexpected.
You're an idiot, but you know that right? You're list shows you have no real critical thinking skills beyond what you learned from apocolyptic comic books, movies, and video games, but that doesn't stop you from trying act like you have deep thoughts.
The reason I am assuming you know you're an idiot is because you post as AC and have that little scrap of pride.
Try this: They've been working on railguns for ages, as a launch system for ballistic missiles, manned spacecrapft, projectiles, and other purposes. Electronics and triggering systems from that research make their ways into other areas.
Also, you always want to make your systems portable, safer on home turf, and easier to handle.
"Safer on home turf." The problem with explosive delivery systems like cannons, rockets, and guns is that their is a risk of blowing yourself to smithereens. If you can eliminate that from projectile delivery, you become more effective.
Do try to use your brain.
Politics is the art of looking for trouble, finding it everywhere, diagnosing it incorrectly and applying the wrong fix.
No it doesn't. You MUST apply thrust AFTER you reach a suitable altitude in order to get an orbit. There is no way to achieve an orbit purely by firing a gun from the surface, no matter how much velocity it produces. The projectile will either come back down and hit the ground, or fly away and never come back. That means your projectile has to carry a propulsion and guidance system that will survive the humungous acceleration coming out of the gun.
Earth rotation does reduce the total energy you have to apply, which is why most satellite launches are eastward, but it can't eliminate the need for an injection burn.
rj
But that means you need a rocket that is orders of magnitude smaller.
Rethinking email
Charging 33Mj in 300s is only 110KW. A US house typically takes from the grid 200A at 220V: 44KW max (uses a special panel to distribute it; standard is 100A:22KW). So two neighbors and I could charge this thing in just about 4 minutes. It consumes only 9.17KWh, which costs under $1 from the average US grid utility. A US car floored at about 200KW would charge it in 2m45s.
Of course the real action is in the firing, when 33Mj is released in (FTA) 10ms. That's 3.3GW, which powers 1.65 million typical US homes (typical SF-sized city + immediate suburbs) at their 1KW average consumption (non-electric heating: if all electric heated, that's about 200,000 Northeast homes in January). At about 35Mj:gal that's only about 9 gallons of gas at 100% efficient electric generation; a typical high-end generator at 20% needs about 45 gallons for each shot.
Of the storage, quick charging and even quicker discharging this railgun demonstrates I hope the Navy produces even more productive research in just the storage and quick charging efficiencies. Naval ships probably won't want to wait 5 minutes, or even 5 seconds, to reload, so 1.1MW charging is a good target. I don't know whether these capacitors charge in a massively parallel array, but they should; I'm not really sure why all modern batteries don't charge many subcells in parallel for faster charging than discharging - though this gun will never achieve that rate, even if charged on shore by a nuke plant (typically 2-3GW). More research, especially basic science in electrochemistry on nanomaterials, would improve electric appliance performance, especially in our critically growing mobile devices.
But storage density is the key factor. Destroyers typically carry about 200Kgal of fuel retaining about 25Kgal reserve, plus about 30Kgal jet fuel. A fuel cell at 70% efficiency would need only about 22 gallons per shot; 1000 shots would be less than the reserve. These caps are designed for fast charge/discharge, not capacity, since they're much larger (at least a couple shipping containers, over 5000 cubic feet, instead of 6CF). We need supercapacitors that can store greater than gasoline's 35Mj:l (and better than its 45Mj:Kg). At large scales, capacitors should be much smaller and lighter than gasoline, since each cap atom should store more electrons than in the one or two max in each chemical bond in fuel molecules (and which never completely, or even mostly, "discharge"). This project probably won't do that kind of research, but it could feed other research into that much harder and more common problem of increased storage density.
In the meantime, it's great the Navy will be able to move to very powerful electric guns. Instead of fuel energy locked up in separate propulsion turbine tanks and ammo charges, the whole mission can be more flexible with electric powering everything. Fuel cells can double or triple (or better) the conversion efficiency, while eliminating emissions (and generating drinking water at sea with no extra energy consumed). Which all means more efficiency, which means less fuel carried around, which means even more efficiency. Ships might eventually carry square KMs sheets of solar panels to float around them, generating a megawatt (in daytime) for charging caps that fire every 5 seconds or faster.
And the more we get the Navy energy efficient, the less the Pentagon will demand we stay at war to protect global oil supplies, and the more it will prioritize energy innovation that keeps America more independent and effective generally. Which means less shooting, which is the real (and only legitimate) goal of the military: to end wars with America victorious, either by superior force or by avoiding them entirely.
--
make install -not war
This kind of R&D will lead to new ultra-caps, but also a much better understanding of how to make things go fast CHEAPLY. For the moment, this is about throwing 25 lbs 200 miles. Once this is done, then we will likely see a new one that will be capable of throwing 1000 or more lbs STRAIGHT UP say 200-300 miles. Once that occurs, it would be possible to send up very cheaply water and nano sats designed to withstand that kind of Gs.
I prefer the "u" in honour as it seems to be missing these days.
The main advantage of a rail gun is that its muzzle velocity is not limited by the sound speed in a hot gas. Guns that use chemical propellant can't have arbitrarily high muzzle speeds because the propellant gas can't be arbitrarily hot. If you want to go faster, you have to switch from a gun to a rocket and carry the propellant with you. A rail gun gets you back to a gun with rocket speeds and ranges but faster. Since the response can be faster than a rocket, it can provide missile defense by the barrage method and be very effective. It could also be used as intercontinental ballistic artillery eventually. Very powerful and destabilizing....
It is difficult to understand how you could have pulled that BF quote so far out of context. It was referring to the devaluation of currency being effectively a tax and was not related to income tax whatsoever. If anything is would be similar to a tax on the value of savings and investments (not the numeric amount), due to inflation.
Even if it were referring to income tax (e.g. "the most equal of all taxes...is generally proportional to Men's income"), it is per the wording not a progressive tax. A Tax is a nominal value of money paid for some reason, not a rate. Progressive taxes are by definition defined by a tax RATE that is proportional to income/assets/whatever. In a progressive tax, not only does a person with more taxable assets pay more in taxes due to a fixed percentage of the larger value... the percentage itself rises. This is not what is referred to here. Fail.
(Now one could argue that a flat tax on paper assets integrated over time is a progressive tax, since wealthier people would potentially have more money "in the bank" being taxed in relation to total assets, which may be true... The interesting bit about that is it would punish those who saved paper assets, which would likely result in the wealthy moving away from that paper currency as a container of wealth. Franklin argued against use of Gold and metals as wealth containers since the prices were volatile at the time, and with paper effectively taxed, by deflation, other methods of escaping the deflation would likely be sought.)
If you can look at those charts and see any trendline I applaud you. To me it appears the numbers are statistically brownian noise.
Your first paragraph is ok, but then you dive into the deep end... You give no basis for why para 1 is "poison to democracy". Speaking of which, what is this Democracy to which you refer? People like you, with no basis in economics, or civics, are what make the long term prospects of the US "not good".