Talk-Polywell.org

Or at least other nuclear power sources on their ships.
http://nextbigfuture.com/2010/03/railgun-video.html

Not trying to temper the enthusiasm though, I want to add that railguns were "coming" already when I first read about them almost 30 years ago in a science magazine. I am wondering why there has been so little progress ever since.

I think that video is the previous 8MJ one. Here is the 32MJ one, tested so far up to 10MJ.

http://www.defenseindustrydaily.com/bae ... pon-01986/

http://www.popsci.com.au/military-aviat ... le-railgun

http://www.navweaps.com/Weapons/WNUS_Rail_Gun_pics.htm

http://thetension.blogspot.com/2008/02/ ... -most.html


Want to make your own? Very cool animation on second video.
http://hackaday.com/2010/01/01/making-a-rail-gun-again/

2020 is still a long way off though. Sigh, things just dont go fast enough, only thing that seems to go to fast is my age progression

http://gizmodo.com/5402607/us-army-rail ... first-time

This is a good photo of the current navy project. Don't let the "army" tag mislead you. It was a multiple round test conducted at dugway. The test article is a proof of concept build for the ship mounted design. Notice the circular power feeds around the breach. One of the parts of this design I am still fishing around for is the actual round feed mechanism, whether or not it uses a high speed injector. The injector method has been used before as a means to reduce barrel wear/and increase weapon life.

Skipjack wrote:2020 is still a long way off though. Sigh, things just dont go fast enough, only thing that seems to go to fast is my age progression ;)

Wait 'til you get old. Things slow down because every second is a miracle.

Wait 'til you get old. Things slow down because every second is a miracle.

If I keep aging at the current rate, that will be very, very soon.

They are calling it "Blitzer"

Google that and you will find some info.

FYI


A stick of dynamite contains roughly 2.1 MJ of energy.

Axil wrote:A stick of dynamite contains roughly 2.1 MJ of energy.

thx. Nice to know - but its not all in the same direction and I'm not sure how to equate them.

Landing a kg of "kinetic weapon" at orbital velocity is equivilent to landing ~7 kg of TNT. POW!!!

One reason for early excitement on railguns was the interpretation of the equations under which they were assumed to operate predicted action without a reaction. I've never tracked the arguments down completely, but it seems to have something to do with Maxwell's Equations being covariant instead of invariant. Peter Graneau the Elder was one of the earlier workers in the field, and concluded Lorentz was missing an important term in his electrodynamics equations. Long story, much controversy

The prediction was wrong, of course: one of those cases of "In theory, theory and practice are the same ... in practice they aren't." Railguns kick like a mule. So they are not able to be as powerful and as easily toted as first hoped.

Tom Ligon wrote:One reason for early excitement on railguns was the interpretation of the equations under which they were assumed to operate predicted action without a reaction. I've never tracked the arguments down completely, but it seems to have something to do with Maxwell's Equations being covariant instead of invariant. Peter Graneau the Elder was one of the earlier workers in the field, and concluded Lorentz was missing an important term in his electrodynamics equations. Long story, much controversy

The prediction was wrong, of course: one of those cases of "In theory, theory and practice are the same ... in practice they aren't." Railguns kick like a mule. So they are not able to be as powerful and as easily toted as first hoped.

As I understand it, both Ampere and Weber derived "Maxwell's equations" long before Maxwell, but rejected them as too simplistic and not satisfactorily explaining all EM phenomena.

Basically, "Maxwell's equations" (actually Hertz' re-write of Maxwell's equations) are incomplete.

Graneau backtracked Maxwell's equations thru Lorentz to Grassmann and then Ampere. Ampere actually had a fairly complete analysis considering he had only worked on it for a couple of weeks after witnessing a demonstration of Orsted's compass and current-carrying wire experiment.

Grassmann supposedly decided to use electrodynamics as a nice problem with which to demonstrate the utility of vector calculus. However, he noted one term cancelled out around a closed loop circuit, and dropped it from his equations. The term is supposed to become signicant at very high currents, and Graneau calls it "Amperian tension". It supposedly produces actual tensile loading in conductors. It should be a player in railguns. Graneau belives his observations of railgun behavior say the term is real.

Another question is, what of antennae? A typical antenna is an open circuit, and deleting the term might be invalid in that case.

I'm just a casual observer on this topic. I got suckered into doing a quick and dirty low-power railgun test based on an anomoly Graneau reported, and was able to more or less reproduce it. Wound up getting a call from Graneau, who admitted he had never attempted to replicate the test (a ferrous projectile moves the wrong way from the more common copper projectile). He was too spooked by it to repeat it. My reaction was that my simplistic understanding of how the things work said the movement made sense (iron is attracted by magnetic fields, so it moves to the current-carrying parts of the rail .... duh), and you are on shaky ground if you publish what you can't replicate (see WB6). Publishing what you refuse to replicate is wierd.

I'm absolutely convinced that theoretical physicists try to make magnetic fields too simple.