Latest Naval Railgun Demonstration - Page 1
Forum section: electronics / general

author: SgtRock
author_rank: Unknown
timestamp: January 30, 2012, 10:08:35 pm
content: Greetings EEVBees:-- Awesome, Dude. I wonder if they use Flux Capacitors. How many Jiga Watts does that thing use? I wonder how many parsecs it would take to do the Cassel Run. Maybe Dave can get one of these, for a tear down.http://news.cnet.com/8301-13772_3-57367745-52/futuristic-navy-railgun-with-220-mile-range-closer-to-reality/"Get ready, little lady. Hell is coming to breakfast."Chief Dan George 1899 1981Best RegardsClear Ether

author: G7PSK
author_rank: Super Contributor
timestamp: January 30, 2012, 11:07:54 pm
content: If there is no chemical propellant what is creating all that smoke and flames as the projectile is launched. I can also see one main drawback of an electrical or electronic system,just when you need it it most one of the capacitors blows, at least with conventional guns you hit the cap and it pops.When do they get photon torpedoes?

author: A-sic Enginerd
author_rank: Regular Contributor
timestamp: January 31, 2012, 12:15:30 am
content: Didn't read the article, but last I heard they were up to 33MJ. Yes, you read that right 33 MEGA Joules.Think I saw somewheres a while back they built the thing to have a peak capacity of something like 150MJ, but don't quote me on that.All the fire, explosion and what nots is plasma as a result of the energy release and the projectile impacting, well....the air.

author: tom66
author_rank: Super Contributor
timestamp: January 31, 2012, 12:23:33 am
content: So, umm, using a screwdriver to discharge the caps would be abadthing?

author: AntiProtonBoy
author_rank: Frequent Contributor
timestamp: January 31, 2012, 12:38:47 am
content: I'd imagine the prototypes had the coils completely destroyed after each operation. That's one of the few things that must be fixed, and even then, the wear and tear on the coils will be relentless.

author: A-sic Enginerd
author_rank: Regular Contributor
timestamp: January 31, 2012, 12:52:17 am
content: Quote from: AntiProtonBoy on January 31, 2012, 12:38:47 amActually, no coils. But yes, lots of rebuild has to happen between each shot. Best case is maybe a couple shots before much rework is needed, but yeah that's what some of the research is all about - how to make it work without a complete redo after each shot.Like you, I thought I knew what a "rail gun" was, then some months back a buddy and I came up with an idea for a "rail gun" project. Started some research and that's when I got an education in the differences between a rail gun, a coil gun, a linear accelerator, etc etc etc.

author: Rufus
author_rank: Super Contributor
timestamp: January 31, 2012, 12:57:19 am
content: The story isn't about the latest demonstration it is about a contract being signed, the record breaking demonstration was more than a year ago.Never really looked at rail guns till now. The discharge current passes between rails via the projectile. The flames and smoke are from the rails and projectile partially being destroyed by the enormous currents and heat.Not quite sure what was demonstrated, the 33MJ appears to be the input power to the gun, mach 0.75 isn't very impressive, the projectile would have to weigh about 1300kg to have 33MJ of kinetic energy at mach 0.75 (if I got the sums right).I did some quick sums on capacitors too. I reckon you get about 0.8kJ per liter of capacitor (high voltage electrolytics) whole lot of capacitor for 33MJ.The main problem is going to be the rails wearing out and you have wonder how straight it shoots with a worn barrel and if they claim very long range as a significant advantage it is going to have to shoot really straight.

author: Unknown
author_rank: Unknown
timestamp: January 31, 2012, 01:00:10 am
content: Coils or not their conductors have to be superconductive (??) cooled down to a few K. Unless it is one of those collapsing field devices.The article says 0.75 Mach speed which is a bit low, don't you think?

author: A-sic Enginerd
author_rank: Regular Contributor
timestamp: January 31, 2012, 01:11:15 am
content: Yeah, I was a little confused by the 0.75 Mach thing too. (went and read the article a min ago). When I last looked at this a year ago I thought I saw something like 4K mph on the 33MJ shot. Want to say the projectile is something like 26 lbs.....or 26Kg......don't recall exactly and I'm too lazy to google it right now, but it was something in that range.Don't recall if there was mention about what material they're using for rails, but a lot of more "common" rail guns use various copper alloys. Go google around and you'll see a bunch of pretty crazy stuff being built in peoples garages.

author: G7PSK
author_rank: Super Contributor
timestamp: January 31, 2012, 09:03:33 am
content: I have just been reading up on the rail gun, First invented 1918. But I can see where the US military are going with, It would appear that you could use it to fire a ball of plasma at high enough speeds to trigger a nuclear explosion, just think of the destructive possibility of one of those mounted on an orbital platform,Nuke anything without dropping a bomb.Is it not about time that man put his greater energies to something more constructive.

author: siliconmix
author_rank: Frequent Contributor
timestamp: January 31, 2012, 09:51:05 am
content: thats one power hungry weapon.it'' never catch on .mind you i said that about mobile phones

author: westfw
author_rank: Super Contributor
timestamp: January 31, 2012, 10:04:39 am
content: Misplaced decimal place, I think. Earlier articles claim Mach 8.http://www.wired.com/dangerroom/2010/12/video-navys-mach-8-railgun-obliterates-record/

author: ejeffrey
author_rank: Super Contributor
timestamp: January 31, 2012, 10:37:27 am
content: Quote from: G7PSK on January 30, 2012, 11:07:54 pmIts a matter of comparing worst case scenarios. If a current warship has a fire in the magazine, it is in a *bad* way. Obviously they do everything they can to prevent this situation, but if those resources could be spent elsewhere there is the possibility that you could come up with an overall more effective unit. Electromagnetic weapons also promise potentially higher velocity projectiles and lower overall weight due to not having the lug around propellant.

author: Rufus
author_rank: Super Contributor
timestamp: January 31, 2012, 12:29:55 pm
content: Quote from: westfw on January 31, 2012, 10:04:39 amThink this rail gun thing is mostly a demonstration of how abysmal media reporting of vaguely technical issues is.The article also says 5500 ft/s which is about mach 5 not 8. It also says the ultimate aim is to have a 'bullet' travel 200 miles in 6 minutes - about mach 2.5 average. It also mentions a 23 pound bullet (although from some of the article comments that used to say 23-pound kilogram bullet). A 23 pound bullet at mach 8 has more than 33MJ of kinetic energy.

author: Unknown
author_rank: Unknown
timestamp: January 31, 2012, 01:35:49 pm
content: Its not like military have any intent of reporting accurate data either. They will obfuscate information as a matter of course. It is not like they are trying to hide information from an enemy. The enemy probably already knows the system down to the thread of the fasteners. More likely they are trying to gain publicity and hence funds without letting the American public into the nitty gritty details like cost.

author: Time
author_rank: Frequent Contributor
timestamp: January 31, 2012, 03:42:37 pm
content: The 33 MJ of energy is probably the .5CV^2 energy of the marx bank that powers the gun, not the kinetic energy of the projectile.

author: SoftwareSamurai
author_rank: Regular Contributor
timestamp: January 31, 2012, 04:28:41 pm
content: Quote from: G7PSK on January 30, 2012, 11:07:54 pmAt those velocities, the projectile is literally super heating the air as it travels - much like a meteorite as it impacts the upper atmosphere - and causing the oxygen atoms to "ignite", hence the smoke and flames.Look closely, and you can see the mach shockwave produced by the projectile. Nowthat'swhat I call extremely impressive!Quote from: G7PSK on January 30, 2012, 11:07:54 pmThat...is a very good question!Let's say we're talking about launching a ball of plasma. Now we can easily create a ball of plasma, but there's three issues with "shooting" them:1. They tend to expand and self-extinguish rather quickly. However, in some videos we see that a rapidly spinning ball of plasma may, for some unknown reason, maintain its integrity for a surprisingly long time.2. Once created, they tend to wander wherever they want, so getting them to travel in a specific direction is akin to cat herding.3. Even if we do somehow manage to "shoot" one, I'm pretty sure it would self-extinguish even faster while traveling through our atmosphere. In fact, I'm pretty sure that the faster it travels through the air, the faster it would evaporate into nothing but a puff of smoke.So if you can figure out how to create a "stable" ball of plasma (one that doesn't vaporize itself for at least a few seconds), and figure out how to launch said stable ball of plasma in the direction you want, then you'd be the first person to create a "photon torpedo".Be sure to video document your experiments. We need all the laughs we can get these days!

author: Time
author_rank: Frequent Contributor
timestamp: January 31, 2012, 06:11:41 pm
content: vaporize plasma...lol funny statement.