The "Texas Site" which was originally found at http://halluc.snakeden.org/railgun/ and was killed ruthlessly by the slashdot effect hs now being mirrored here:
You can certainly get around using capacitors by going to a homopole generator or a compulsator, but that's beyond the scope of an amateur project like ours. It's also not an easily portable solution, but a tank could certainly haul around a compulsator.
We are forced to use capacitors because its the only thing we're likely to find lying around. We have six 4000V 150uF caps, which all together weigh a few hundred pounds.
-mouser
railgun.org
Re:What they had to say about getting slashdotted.
on
DIY Railgun Projects
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· Score: 1
Yes, you'll be happy to know that the list membership was 23 last night. Now it stands at 104.
You're thinking of a coilgun. Different principle. Coilguns move a magnetic projectile through a coil like a solenoid moves its armature.
Railguns move a non-magnetic projectile along the rails with an induced field via the Lorentz force. Theoretically, the railgun is the more powerful design since there is a limit to how much field amplitude can be gained from an electromagnet of reasonable size. but an induced field is limited only by the amount of current you can push into the rail loop.
There are actually prototype designs in the literature for multi-stage railguns, but nothing much has come from that research.
Yes, the railgun is effectively a single-turn inductor. But it does not collapse in on itself, it expands via the Lorentz force.
"a long coil with many windings, and a magnetized firing slug that pushes the projectile out."
That's a coilgun, which is something completely different. Coilguns are much simpler to build, but aren't capable of as much muzzle velocity because there's only so big an electromagnet can be mdae (we can induce a field on the order of ~1T). Railguns are not more efficient that coilguns, they just offer more potential.
In my design (and John's design), the armature is the projectile. In a plasma armature design, the armature is completely vaporized and shoots out the end of the barrel behind the projectile as a big firey muzzle flash. This is actually desired, since plasma is a very efficient conductor. We chose not to try this design because it requires an air-tight barrel and tighter design tolerances.
I plan to mirror John's site on railgun.org, but he needs to be able to get to his content first. I'll post here when I've got it.
-mouser
railgun.org
To say that this directive is not sucessful isn't really justified based on the recent losses. Missions to Mars have had an abysmal succcess rate ever since the first Mars mission, Koralb 4, failed to launch properly.
Currently, there have been 33 missions to Mars from Earth, 8 of which have been mostly sucessful. Fully two thirds of the missions to mars have been 100% unsucessful, and most of those that have returned some useful data have failed at some point earlier than expected.
If you thought the navigation error (damn those English units...) that led to the demise of the Mars Climate Orbiter was embarrassing, just remember that the Viking landers 1 and 2 were both rendered useless far before the end of their operational lifetime when the Viking 1 lander, acting as a communication relay for the other lander, was mistakenly shut down.
I think the Smaller, Cheaper, Better paradigm is a commendable one, and deserves more of a chance. Why Mars seems to be such a difficult planet to get to deserves a closer inspection as well. Our success rate in every other space endeavor has been an order of magnitude higher, but it has nothing to do with NASA's attempts to make its new spacecraft more economical.
Indeed, the discovery that Mars has only the odd water molecule here and there (or no water at all) would tend towards the conclusion that colonizing Mars wouldn't be cost effective for the time being.
If there's no water on Mars, and colonization is the prime goal of our exploration there, then we might as well colonize the moon first. Cheaper, closer, and all the alumninum we want.
What makes the exploration of Mars so interesting is that we don't know that there aren't actually large quantities of water there. We should really know definitively that there is no appreciable water supply there before we discount it as a possible colonization sight.
1) What caused the climate of Mars to change? Is Earth in danger of a similar change, and can we be taking steps to prevent that?
2) Did primitive life exist on Mars, and if so, how does it compare to primitive life on Earth?
3) Are there natural resources on Mars worth mining and returning to Earth?
Basically, learning about Mars gives us something to compare our study of Earth against, and may give us a source of resources (and real estate) to help us overcome our rapid depletion of Earth's resources.
Slashdot Mirror
OK, TA-33 is a radio telescope, part of the Very Large Baseline Array (VLBA). It is, by all accounts, one of the least-sensitive parts of the lab.
So when this guy comes out and says things like TA-33 being focused in part on "black-ops," it's nothing but gonzo journalism.
This article is so full of technical inaccuracies that it isn't worth considering. Pure theater.
There's actually three locks up there now. Medeco, Primus, and Yale, all on the same door. Doesn't seem to pose much of a problem...
The "Texas Site" which was originally found at http://halluc.snakeden.org/railgun/ and was killed ruthlessly by the slashdot effect hs now being mirrored here:
http://web.mit.edu/mouser/www/railgun/halluc/
Unfortunately, I was not able to include the movies of the gun firing as my disk quota is full.
-mouser
railgun.org
You can certainly get around using capacitors by going to a homopole generator or a compulsator, but that's beyond the scope of an amateur project like ours. It's also not an easily portable solution, but a tank could certainly haul around a compulsator.
We are forced to use capacitors because its the only thing we're likely to find lying around. We have six 4000V 150uF caps, which all together weigh a few hundred pounds.
-mouser
railgun.org
Yes, you'll be happy to know that the list membership was 23 last night. Now it stands at 104.
:)
-mouser
railgun.org
You're thinking of a coilgun. Different principle. Coilguns move a magnetic projectile through a coil like a solenoid moves its armature.
Railguns move a non-magnetic projectile along the rails with an induced field via the Lorentz force. Theoretically, the railgun is the more powerful design since there is a limit to how much field amplitude can be gained from an electromagnet of reasonable size. but an induced field is limited only by the amount of current you can push into the rail loop.
There are actually prototype designs in the literature for multi-stage railguns, but nothing much has come from that research.
-mouser
railgun.org
Have you ever built an AK-47 from raw metal?
I'll pit your professionally-produced AK-47 against the DoD 5,000,000 Amp, 4 kilometers/second muzzle velocity, 5 kg projectile railgun any day.
Alternatively, I'll pit my homebrew railgun against your homebuilt zipgun and homemade bullets and we'll see what's more impressive.
-mouser
railgun.org
Anyway, I'll be mirroring his site soon.
-mouser
railgun.org
Yes, the railgun is effectively a single-turn inductor. But it does not collapse in on itself, it expands via the Lorentz force. "a long coil with many windings, and a magnetized firing slug that pushes the projectile out." That's a coilgun, which is something completely different. Coilguns are much simpler to build, but aren't capable of as much muzzle velocity because there's only so big an electromagnet can be mdae (we can induce a field on the order of ~1T). Railguns are not more efficient that coilguns, they just offer more potential. In my design (and John's design), the armature is the projectile. In a plasma armature design, the armature is completely vaporized and shoots out the end of the barrel behind the projectile as a big firey muzzle flash. This is actually desired, since plasma is a very efficient conductor. We chose not to try this design because it requires an air-tight barrel and tighter design tolerances. I plan to mirror John's site on railgun.org, but he needs to be able to get to his content first. I'll post here when I've got it. -mouser railgun.org
I'll be mirroring the texas site on railgun.org as soon as John can get the content off his server. -mouser www.railgun.org
Currently, there have been 33 missions to Mars from Earth, 8 of which have been mostly sucessful. Fully two thirds of the missions to mars have been 100% unsucessful, and most of those that have returned some useful data have failed at some point earlier than expected.
If you thought the navigation error (damn those English units...) that led to the demise of the Mars Climate Orbiter was embarrassing, just remember that the Viking landers 1 and 2 were both rendered useless far before the end of their operational lifetime when the Viking 1 lander, acting as a communication relay for the other lander, was mistakenly shut down.
I think the Smaller, Cheaper, Better paradigm is a commendable one, and deserves more of a chance. Why Mars seems to be such a difficult planet to get to deserves a closer inspection as well. Our success rate in every other space endeavor has been an order of magnitude higher, but it has nothing to do with NASA's attempts to make its new spacecraft more economical.
If there's no water on Mars, and colonization is the prime goal of our exploration there, then we might as well colonize the moon first. Cheaper, closer, and all the alumninum we want.
What makes the exploration of Mars so interesting is that we don't know that there aren't actually large quantities of water there. We should really know definitively that there is no appreciable water supply there before we discount it as a possible colonization sight.
Aside from colonization, which is one hundred years away at best, there are a multitude of scientifically interesting reasons to explore Mars.
1) What caused the climate of Mars to change? Is Earth in danger of a similar change, and can we be taking steps to prevent that?
2) Did primitive life exist on Mars, and if so, how does it compare to primitive life on Earth?
3) Are there natural resources on Mars worth mining and returning to Earth?
Basically, learning about Mars gives us something to compare our study of Earth against, and may give us a source of resources (and real estate) to help us overcome our rapid depletion of Earth's resources.