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Gamers May Get a Charge Out of the Gauss Rifle

Soulskill posted more than 2 years ago | from the i'll-order-a-dozen dept.

Hardware Hacking 98

Zothecula writes "Well, Patrick Priebe might have outdone himself with this one. In the past, the German cyberpunk weapons-maker has brought us such creations as a wrist-mounted mini-crossbow, a laser-sighted rotary-saw-blade-shooting crossbow, and a flame-throwing glove. His latest nasty futuristic device? A video game-inspired electromagnetic weapon, called the Gauss Rifle."

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Rail gun ? (1)

PIBM (588930) | more than 2 years ago | (#41238871)

From the description is'nt it more of a railgun type of weapon ?

Re:Rail gun ? (2)

ackthpt (218170) | more than 2 years ago | (#41238919)

From the description is'nt it more of a railgun type of weapon ?

If you've ever played BattleTech, past the original set of Mechs, you've seen Gauss Rifles. IIRC they were introduced about the time of the Clan Invasion (possibly retconned to the Lost Tech)

The only real problem I can see with a Gauss Rifle is the recoil, which could be considerable.

Re:Rail gun ? (0)

Anonymous Coward | more than 2 years ago | (#41239055)

Actually the main problem is that to achieve good efficiency the barrel must be very long.
Also you need a fast power supply, which is a major problem for any electromagnetic gun.

Re:Rail gun ? (3, Informative)

ackthpt (218170) | more than 2 years ago | (#41240379)

Actually the main problem is that to achieve good efficiency the barrel must be very long.
Also you need a fast power supply, which is a major problem for any electromagnetic gun.

Ever see those people with their little RC dragsters? One turn of wire armatures with high current draw cells to power them? I think science has this covered by now, it's only a question of how big a projectile you want to lob. The US Navy has been experimenting with these for years and plan to equip ships with them, capable of lobbing shells well over one hundred miles, at mach 5 or better. Power supplies capable of high current draws and perhaps arrays of capacitors and you're well on your way.

Re:Rail gun ? (1)

drinkypoo (153816) | more than 2 years ago | (#41244163)

It's really got to be caps because batteries are tempermental and can only be recharged so many times and most of them seem to be inherently horrible things to have on fire. They use plenty of batteries, but if you're going to be stacking them up in piles then you're going to want capacitors.

Re:Rail gun ? (0)

Anonymous Coward | more than 2 years ago | (#41245403)

if you sit on a nuclear plant on fire, having some battery meltdown is not your primary concern.

Re:Rail gun ? (1)

LongearedBat (1665481) | more than 2 years ago | (#41250139)

shells well over one hundred miles

Man! That's some amazingly big ammo.

Re:Rail gun ? (3, Insightful)

darthdavid (835069) | more than 2 years ago | (#41239333)

Gauss rifles had been around since the star league, as with most things the Clan versions were just better than their IS equivalents.

Re:Rail gun ? (3, Funny)

Anne_Nonymous (313852) | more than 2 years ago | (#41238921)

Don't be silly; everyone knows you don't bring a railgun to a watermelon fight.

Re:Rail gun ? (1)

DarwinSurvivor (1752106) | more than 2 years ago | (#41243119)

Damn straight, you bring TWO!

Video Game Inspired? (1)

Jeremiah Cornelius (137) | more than 2 years ago | (#41238957)

This was in SF books, in the 70's.

As for gaming antecedents, do you remember the role-playing system, Traveller?

When I was a teen - around '79, I remember Gauss Rifles, and polyhera dice in the game. This was when the video-game combat state-of-the-art was Asteroids and Space Invaders...

Re:Video Game Inspired? (1)

Chris Burke (6130) | more than 2 years ago | (#41239593)

Yes. Video-game inspired, because that's what inspired him to do it. Video games. Not 70s SF books. There's a chain of inspiration connecting them, but that's not the same thing.

It's the same way in which Nite Owl was inspired by Batman, rather than Zorro, even though Zorro was the inspiration for Batman.

Nothing wrong with knowing the history, of course. But "video game inspired" is still correct.

Re:Video Game Inspired? (1)

jmorris42 (1458) | more than 2 years ago | (#41240669)

> But "video game inspired" is still correct.

Except the weapon in the game wasn't called a Gauss Rifle and the one in Traveller was. So it tells me the guy knew exactly where his idea actually came from but wanted the increased pageviews from a videogame tie in. Sometimes it helps to read the article. :)

Re:Video Game Inspired? (2)

Chris Burke (6130) | more than 2 years ago | (#41240767)

You mean the article where he explicitly says his inspiration was a weapon from Crysis 2?

Gauss Rifle was the term used in Traveller, but not only in Traveller, it's mentioned in many other places including games, which is why I knew exactly what a Gauss Rifle was despite never having heard of Traveller.

So it doesn't actually tell you that Traveller was his inspiration at all.

Re:Video Game Inspired? (1)

GameboyRMH (1153867) | more than 2 years ago | (#41241797)

I'm pretty sure there was a "Gauss rifle" by exactly that name in STALKER: SoC as well.

Re:Video Game Inspired? (0)

Anonymous Coward | more than 2 years ago | (#41241941)

His inspiration came from someone elses inspiration which came from sci-fi books. Geez.

Re:Video Game Inspired? (1)

Chris Burke (6130) | more than 2 years ago | (#41241995)

Yes. See my first post.

Re:Video Game Inspired? (1)

theshowmecanuck (703852) | more than 2 years ago | (#41242215)

And the guys who created Crysis got the idea from someone earlier who got the idea from someone earlier and so on. As soon as someone figures out how to perfect a ceramic based superconductor, these things will be common place. And will be very light and orders of magnitude more powerful. Right now at 7.5 pounds this one isn't that heavy considering it is home built. I know it's supposed to be a sort of pistol, but I used to lug around a 10 pound FN rifle. 7.5 pounds isn't so bad. And in comparison to a Sterling SMG (around 6 pounds empty... probably around 7 pounds loaded) it isn't that much heavier. FWIW, the Sterling was used as the Star Wars storm troopers main weapons in the original Star Wars. They put a fake sight on top and used the 10 round magazine that truck drivers could load (since the curved 30 round side mounted magazine would be impeded by the door/window frame). Of course they made them extra high power with special effects 'blaster bolts'.

Re:Video Game Inspired? (1)

BlueStrat (756137) | more than 2 years ago | (#41243155)

I know the Gauss Rifle has been a standard piece of weaponry in the Mechwarrior series from the BattelTech universe.

Still have fond memories of configuring MW4MERCS/VENG "pop-tart" "gauss-boat" sniper 'mechs (mech with jump-jets and loaded with all the gauss-rifles it can carry, maybe with an additional laser or two if room permits) that could suddenly pop up over the crest of a medium-distant hill/ridge and salvo-fire all weapons and ruin an unwary opposing mechwarrior's whole day.

Strat

Re:Video Game Inspired? (1)

dadioflex (854298) | more than 2 years ago | (#41243881)

Nite Owl was inspired by Blue Beetle, the original Charlton character Alan Moore wanted to write about. And the Gauss rifle or coil gun was invented and built in the 60s by Kristian Birkelan, which then inspired 70s SF I guess.

Does he do requests? Re:Video Game Inspired? (1)

GoodNewsJimDotCom (2244874) | more than 2 years ago | (#41239723)

I want to see a Quake 1 lightning gun.

Re:Video Game Inspired? (1)

Dr. Spork (142693) | more than 2 years ago | (#41240001)

"Busted in the Sword Worlds with a loaded gauss gun!"

Re:Video Game Inspired? (1)

styrotech (136124) | more than 2 years ago | (#41240695)

As for gaming antecedents, do you remember the role-playing system, Traveller?

That was my first thought too. I seem to remember they were part of the Mercenary book (or something - it's been a long time).

Re:Video Game Inspired? (1)

CrimsonAvenger (580665) | more than 2 years ago | (#41242941)

As for gaming antecedents, do you remember the role-playing system, Traveller?

That was my first thought too. I seem to remember they were part of the Mercenary book (or something - it's been a long time).

Exactly right. Standard TL12 infantry weapon.

Does the fact that I remember this, but not where I left the gas can for my lawnmower, mean anything?

Re:Video Game Inspired? (1)

Patchw0rk F0g (663145) | more than 2 years ago | (#41245553)

That was my first thought too. I seem to remember they were part of the Mercenary book (or something - it's been a long time).

Exactly right. Standard TL12 infantry weapon.

Does the fact that I remember this, but not where I left the gas can for my lawnmower, mean anything?

Unfortunately, yes. Take heart, however: Heinleinian rejuvenation can't be far around the corner...

Re:Rail gun ? (1)

Anonymous Coward | more than 2 years ago | (#41238965)

No, absolutely not. This is a coilgun. Although they are both electromagnetic guns, railguns work differently.

Re:Rail gun ? (5, Informative)

Antipater (2053064) | more than 2 years ago | (#41238981)

No. A coilgun [wikipedia.org] and a railgun [wikipedia.org] are different. The fact that a lot of sci-fi describes the physics of coilguns but calls them railguns causes a lot of misconceptions. But it's pretty simple, seeing as one uses coils and the other uses rails (who'da thunkit?).

Re:Rail gun ? (2)

PIBM (588930) | more than 2 years ago | (#41239137)

Well, the thing is that coilguns are built to shoot ferromagnetic projectiles and he's shooting aluminium pellets. And alluminium is not ferromagnetic (but paramagnetic). Anything I'm missing ?

Re:Rail gun ? (4, Informative)

serviscope_minor (664417) | more than 2 years ago | (#41239211)

Anything I'm missing ?

Yes.

Coilguns actually are good at shooting conductive pellets, since the induced current creates an opposing field and force. The best pellets are often iron cored with a thick copper sheath, giving the best of both worlds.

Re:Rail gun ? (0)

Anonymous Coward | more than 2 years ago | (#41239315)

TFA says steel, it's obviously a coilgun (and I suspect a suboptimal one at that -- there's plenty of hobbyist research in coil spacing, and there's no sane way to pack four stages into that short a gun), what in hell would a multi-stage risk gun even be?

Re:Rail gun ? (1)

Michael Woodhams (112247) | more than 2 years ago | (#41239347)

Anything I'm missing ?
12 seconds into the video: "Projectiles: 5.6 x 16mm steel"

Re:Rail gun ? (1)

Antipater (2053064) | more than 2 years ago | (#41239407)

Some designs have non-ferromagnetic projectiles, of such as aluminum or copper, with the armature of the projectile acting as an electromagnet with internal current induced by pulses of the acceleration coils.

From TFWiki.

Re:Rail gun ? (1)

Eroen (1563375) | more than 2 years ago | (#41244845)

Stop giving silly names like "coilgun" Birkeland's venerable Electromagnetic Gun. (patent [google.com] (1902) (A fanciful tale, worth reading))

Re:Rail gun ? (1)

Medievalist (16032) | more than 2 years ago | (#41239625)

You mean like Schlank Emma, Big Bertha, or Schwerer Gustav? [wikipedia.org]

Re:Rail gun ? (1)

KDR_11k (778916) | more than 2 years ago | (#41252455)

Big Berthas aren't rail-mounted.

Re:Rail gun ? (1)

Medievalist (16032) | more than 2 years ago | (#41259175)

Neither was Schlanke Emma. You got the meta-joke!

Re:Rail gun ? (1)

slick7 (1703596) | more than 2 years ago | (#41240033)

From the description is'nt it more of a railgun type of weapon ?

I can see so many ways for this to go wrong on so many levels.

Re:Rail gun ? (0)

Anonymous Coward | more than 2 years ago | (#41242303)

It is a railgun. The summary was written by a fucking moron.

inspired by what? (1)

Eponymous Hero (2090636) | more than 2 years ago | (#41238935)

are we talking starcraft gauss rifle? fallout 3/new vegas gauss rifle? it looks like it belongs in dead space. it also looks like a glorified version of this http://www.youtube.com/watch?v=QPciBQnZw3c [youtube.com]

Re:inspired by what? (0)

Anonymous Coward | more than 2 years ago | (#41239057)

Crysis 2, right in TFA

oh... right... forgot where I was

Beretta 92F (0)

Anonymous Coward | more than 2 years ago | (#41238945)

If remember well Beretta 92F is about 500J.

How long till we get a skull gun? (0)

Anonymous Coward | more than 2 years ago | (#41238953)

If this man is really looking to cyberpunk writing, then perhaps he'll follow recent advancements in implanted electronics and, taking a cue from Neil Stephenson's The Diamond Age [amazon.com] , offer us a gun that can be concealed in the cranium. Then again, if you set off the metal detector at a location even when walking through completely naked, someone's going to know that something is up.

Re:How long till we get a skull gun? (1)

newcastlejon (1483695) | more than 2 years ago | (#41239199)

Skul-gun?

Power density strikes again... (3, Insightful)

fuzzyfuzzyfungus (1223518) | more than 2 years ago | (#41238979)

As with electric cars and aircraft, the power density of boring, smelly chemical fuels are just stubbornly competitive with electric tricks...

It's a pity, because they are much more entertaining; but it's persistently the case.

Re:Power density strikes again... (1)

Intrepid imaginaut (1970940) | more than 2 years ago | (#41239041)

I'd say if it was set up in a rifle configuration it could do a bit more damage. Although overclocking this bad boy would definetely be of interest to gamers.

Re:Power density strikes again... (1)

Amouth (879122) | more than 2 years ago | (#41239161)

a rifle version of this would be very interesting, that might be a fun project.

Re:Power density strikes again... (3, Informative)

Hentes (2461350) | more than 2 years ago | (#41239093)

But with chemicals you are limited to the amount of powder you can put in a cartridge, while electric guns can have big batteries attached to them. I still don't think portable electric guns are near, but on a stationary platform with lots of electricity (like ships) they could be effective.

Re:Power density strikes again... (1)

KDR_11k (778916) | more than 2 years ago | (#41252621)

What would a big gun on a ship really do though? The biggest guns modern ships mount are the phalanx anti-air/anti-missile weapons, attacks are performed via missiles or airplanes. What would a railgun add? Increased projectile speed may help to build better flaks but if you've got THAT much power and proper aiming then can't you just build a laser?

Re:Power density strikes again... (1)

Anguirel (58085) | more than 2 years ago | (#41292783)

What would a big gun on a ship really do though?

Indirect Artillery-style Over-The-Horizon firing, with no anti-missile counter measures available to stop it? Being able to spread the acceleration along the barrel instead of requiring a single big explosion might be an advantage somewhere as well (presumably in materials engineering required). Also possibly useful for the rail-gun style underwater shots, where lasers are ineffective, though I'm not sure on the advantage over torpedoes -- possibly speed?

Re:Power density strikes again... (1)

loshwomp (468955) | more than 2 years ago | (#41239197)

As with electric cars and aircraft, the power density of boring, smelly chemical fuels are just stubbornly competitive with electric tricks...

Not really. Electric cars and aircraft have low energy density (aka specific energy aka energy per unit mass), but the power density is outrageously high, even if this particular coilgun specemin is uninspiring.

Re:Power density strikes again... (1)

DingerX (847589) | more than 2 years ago | (#41239207)

Aye. Making the tube longer won't help muzzle velocity much if the propulsion system is magnetic instead of expanding gas. 100 m/s is 360 kph, or pretty damn low for a projectile. And this thing requires a bunch of Li-Ion batteries, and needs a recharge after 50 shots? So, in effect, it's cute toy, but the applications are going to be limited to situations where boring, smelly chemical fuels are simply not an option, but a heavy, electric beast is.

Re:Power density strikes again... (2)

vlm (69642) | more than 2 years ago | (#41239293)

boring, smelly chemical fuels are simply not an option, but a heavy, electric beast is.

Fundamentally a battery basically is a boring smelly chemical fuel, its just in a can and hopefully doesn't make much smoke while it releases its chemical energy. There are some interesting thermodynamic issues with chem fuels and temperatures which can sometimes make a battery reaction more efficient (why the shuttle uses fuel cells instead of a little internal combustion engine to generate electricity, etc). Another reason chem propellants suck is the projectile can never, ever travel faster than the speed of sound of the column of compressed high pressure gas in the barrel, but at least in theory theres no reason an infinitely complicated coil gun couldn't launch stuff at any ridiculous speed.

That "speed of sound in the barrel" is interesting to think about... the pressure is so high in the barrel that the speed of sound might be 2 or 3 times, maybe even more, than the speed of sound in sea level air.

Re:Power density strikes again... (1)

Burning1 (204959) | more than 2 years ago | (#41240949)

Another reason chem propellants suck is the projectile can never, ever travel faster than the speed of sound of the column of compressed high pressure gas in the barrel, but at least in theory theres no reason an infinitely complicated coil gun couldn't launch stuff at any ridiculous speed.

I may be misunderstanding you, but it sounds like you're saying that bullets can't travel faster than the speed of sound? If so, this information is incorrect... Most rifle rounds can exceed the speed of sound quite easily. If I recall correctly, one reason you don't see that many silenced rifles is the fact that the bullets themselves make a pretty tremendous amount of noise traveling at super-sonic speeds.

I know, for example, that the P90 uses a special sub-sonic ammunition when firing with a silencer for this reason. The standard AP ammo flys a little too fast.

Re:Power density strikes again... (1)

Anonymous Coward | more than 2 years ago | (#41241125)

I don't believe that the author is saying that a bullet can't travel faster than the speed of sound outside the barrel (where pressure, at presumably one atmosphere, is relatively low), but that it cannot travel faster than the speed of sound in the barrel at the time the bullet is fired (where the pressure is much higher than 1 atmosphere). As I recall, sound travels through gas much faster when said gas is compressed than it does when that gas is not compressed (note also that sound travels much faster through liquids and solids than it does through air at one atmosphere). As such, increasing the speed of the bullet outside the barrel requires a corresponding increase in the pressure inside the barrel. Therein lies a fairly severe limitation when it comes to how fast you can launch a bullet.

Re:Power density strikes again... (1)

jersey_emt (846314) | more than 2 years ago | (#41242019)

It's not just rifle rounds. Even a .22 LR pistol has no problem breaking the sound barrier.

You are correct with suppressors though. The supersonic "crack" of a projectile is quite loud, and suppressors do nothing to reduce this, except for a small decrease in muzzle velocity. Still, a suppressed rifle is much quieter than an unsuppressed rifle.

Re:Power density strikes again... (1)

Fnord666 (889225) | more than 2 years ago | (#41243249)

It's not just rifle rounds. Even a .22 LR pistol has no problem breaking the sound barrier.

Interestingly most match .22 ammo is subsonic. Apparently when a .22 round transitions from supersonic to subsonic it has a tendency to tumble which is not good for accuracy.

Re:Power density strikes again... (1)

Bob the Super Hamste (1152367) | more than 2 years ago | (#41247031)

The speed of sound within the barrel is dependent on the temperature of the hot gas behind the projectile, not the pressure. As such the projectile cannot exceed the speed of sound of the gas within the barrel. Now since the speed of is dependent on the molecular weight of the gas and the temperature (not pressure) the speed of sound within the barrel is higher than the speed of sound outside of it. A good explination of this can be found on the Wikipedia page about light gas guns in the design physics [wikipedia.org] section. The pressure in the barrel determines the overall potential energy but not the speed of the projectile.

Re:Power density strikes again... (1)

wagnerrp (1305589) | more than 2 years ago | (#41242823)

Another reason chem propellants suck is the projectile can never, ever travel faster than the speed of sound of the column of compressed high pressure gas in the barrel, but at least in theory theres no reason an infinitely complicated coil gun couldn't launch stuff at any ridiculous speed.

That "speed of sound in the barrel" is interesting to think about... the pressure is so high in the barrel that the speed of sound might be 2 or 3 times, maybe even more, than the speed of sound in sea level air.

Almost right. The speed of sound is dependent on the temperature and molecular weight of the gas, but not on the pressure directly. While there is some play with the adiabatic ratio, if you compress a gas and then chill it back to the same temperature but higher density, the speed of sound will not have significantly changed.

Now there are some ways around this issue. Temperature is a big limiting factor, since you can only heat the gas so far before your materials fail. However, you are free to change the composition of the gas inside the barrel. Carbon dioxide, water vapor, and nitrites are all relatively heavy gases. On the other hand, hydrogen is extremely light. Liquid hydrogen rockets run fuel rich, sacrificing potential energy output for the higher exhaust velocity achievable by the lighter, uncombusted hydrogen gas. There is a field of high impact physics that use "light gas guns", using an explosive or hydraulic ram to drive a piston, compressing a large volume of hydrogen into a small barrel as a propellent gas. Projectile velocities upwards of 7km/s have been achieved.

Re:Power density strikes again... (1)

h4rr4r (612664) | more than 2 years ago | (#41239393)

Actually it could help by giving a more ideal coil spacing.

Re:Power density strikes again... (1)

KDR_11k (778916) | more than 2 years ago | (#41252657)

I have no idea how much damage these bullets would do at this speed but a coil gun may work as a silent delivery system for sub-sonic rounds since there are no mechanic parts that would cause a loud snap and keeping the projectile below the speed of sound would prevent the sonic boom as well. Of course a silent gun isn't terribly great if you can't conceal it at all.

Re:Power density strikes again... (0)

Anonymous Coward | more than 2 years ago | (#41253693)

Yeah, or you could just use captive-piston ammo [world.guns.ru] and get gun-like rather than pop-gun-like performance.

Re:Power density strikes again... (1)

Amouth (879122) | more than 2 years ago | (#41239359)

but even with chemical energy being higher, if the video is correct an he can get 30/50 shots per charge and ~500j per shot (personally i question this number).

Ramp up the power and cut the number of shots down and you could have a very scary, very quite, and possibly very effective weapon.

But my bet based on reality is that this is actually nowhere near 500j of output per shot as that is just short of the power of a normal 9mm bullet..

I could see this being a very interesting rifle though

Re:Power density strikes again... (0)

Anonymous Coward | more than 2 years ago | (#41239615)

That's 500J input power, coilguns have <5% efficiency (at least until you make a lot more than 4 stages, with perfect timing and small switching losses).
See http://www.coilgun.ru/ for some earlier example people built.

Re:Power density strikes again... (0)

Anonymous Coward | more than 2 years ago | (#41239797)

You do well to question that number, because it's batshit insane bullshit.

Given the projectile dimensions stated (5.6mm x 16mm) and muzzle velocity (100m/s), it's 16J [google.com] or a bit less, as that doesn't account for the conical ogive, which reduces the mass. This is on the weak side of 22 BB caps.

I didn't watch the video -- is it possible 500J was the input power?

Re:Power density strikes again... (1)

Ryanrule (1657199) | more than 2 years ago | (#41239605)

Within 5 years, we will pass that barrier.

Called it.

Re:Power density strikes again... (1)

fuzzyfuzzyfungus (1223518) | more than 2 years ago | (#41240687)

I suspect that electromagnetic projectile propulsion gets a great deal more interesting if you enjoy the benefit of having nothing but a couple of meters of superconductive feed rail between you and your nuclear reactor(s), which I assume is why the navy is messing around with them. It's in the smaller scale areas where little packets of chemicals have been reliably killing people for several centuries now, and microfusion cells are still a Fallout 3 inventory item...

Re:Power density strikes again... (1)

wagnerrp (1305589) | more than 2 years ago | (#41242851)

The only thing reactors are put on these days are carriers, and submarines. The US Navy would be putting them on gas turbine powered ship, where there would be a large electric generator attached to the propulsion turbines.

My battery is bigger than yours! (0)

Anonymous Coward | more than 2 years ago | (#41238991)

Wonderful! And is it attached to a battery pack the size of a truck trailer?

Re:My battery is bigger than yours! (4, Informative)

vlm (69642) | more than 2 years ago | (#41239183)

You have your engineering constraints wrong.

The battery size reflects the "clip" size. You'll be lucky if your battery size/weight is much smaller than the ammo it flings for a bunch of basic chemistry reasons. A battery the size of a truck trailer would be able to fling a volume/weight of ammo about the size of a truck trailer, either all at once or more likely eventually. In other words the energy density of chemical batteries is never going to be a whole heck of a lot better (like orders of magnitude, not the smallest decimal point) than the energy density of smokeless powder. Hence the intense interest in hypersonic projectiles. I suppose if you had a nuclear aircraft carrier or nuclear powered submarine to power it, then ...

The velocity reflects the weight and number of the coils. Something that is pretty wimpy compared to a slingshot is about the most a human can handle. If you insist on hypersonic velocities its going to be immensely huge and probably quite inefficient as a tradeoff making the whole weapon system fairly useless.

Your budget reflects the total projectile energy via capacitor bank size. Something light enough you can pick up and an individual might be able to afford makes for the worlds wimpiest pellet gun, not much more than airsoft really. If you insist on blowing up a tank, you'll need a truck trailer full of capacitors costing about as much as a house. Capacitors are a really awful way to store energy, but the only way to release the energy quick enough for hypersonic power. If you get serious, internal resistance and crushing magnetic forces and strange resonant effects become a big problem (no longer able to treat the cap as the simple AC/DC electronics 101 simplification of a perfect device anymore)

Usually the limiter for the home builder is triggering followed by power supplies. Whats most likely to stop you is finding a big and bad enough set of SCRs or whatever to handle triggering or if you try mechanical like this guy you end up accidentally building a arc welder, second your average noob is mystified at how to generate more than a couple hundred volts without spending lots of money or getting killed or blowing up the trigger system. If they succeed at that, the next limiter is usually the spectacular cost of high voltage low resistance high capacity capacitors... any 1 or 2 of the 3 isn't going to do, and maxing out all 3 is going to be very expensive. Assuming you pull that off, coils are pretty simple, as are batteries.

Re:My battery is bigger than yours! (0)

Anonymous Coward | more than 2 years ago | (#41239313)

It will also be a factor in charge time. The lower your source voltage + amperage, the more charge time you will need between shots. To take a design of this magnitude to the logical next step of full-auto at the velocities necessary to make it a viable weapon system, the power requirements would be pretty steep, regardless of the longevity of that power supply.

Re:My battery is bigger than yours! (1)

wagnerrp (1305589) | more than 2 years ago | (#41243051)

In all honestly, the "coil gun" concept really doesn't make a whole lot of sense. Electromagnetic coils can't be instantaneously turned on and off. The magnetic reluctance of your coil means it takes some amount of time for the field to come up to strength as power is applied, and some amount of time for the field to dissipate after power is removed. Even if you had tons of stages, and those stages were perfectly timed, the reluctance means that at the switching speeds you need to operate at, you're getting terrible efficiency. It's common for only a couple percent of the consumed electric energy to be converted to kinetic energy in the projectile. Coil guns are fine for large scale linear motors, but the scaling parameters don't work well for something handheld.

If you want a weapon, you want a railgun. Compared to a coil gun, it's dead simple. Make two rails. Put a conductive projectile at one end. Apply low voltage and ludicrous levels of current through the two rails. There's nothing really to control, you just dump everything you can, as fast as you possibly can, into those rails. With proper low resistance materials, energy transfer efficiency can reach into the several tens of percent range. The problem is that just as the projectile is being pushed along the rails, the rails are being pushed apart. As the rails flex away from the projectile, plasma arcing destroys the rails, so the real trouble is finding materials that can withstand the damage repeatedly, so you don't have to re-machine the barrel every couple shots.

Re:My battery is bigger than yours! (0)

Anonymous Coward | more than 2 years ago | (#41249939)

In all honestly, the "coil gun" concept really doesn't make a whole lot of sense. Electromagnetic coils can't be instantaneously turned on and off. The magnetic reluctance of your coil means it takes some amount of time for the field to come up to strength as power is applied, and some amount of time for the field to dissipate after power is removed. Even if you had tons of stages, and those stages were perfectly timed, the reluctance means that at the switching speeds you need to operate at, you're getting terrible efficiency. It's common for only a couple percent of the consumed electric energy to be converted to kinetic energy in the projectile. Coil guns are fine for large scale linear motors, but the scaling parameters don't work well for something handheld.

Unless/until we get good enough superconductors, so you can just energize all coils, chuck a projectile up the breech, then quench each coil as the projectile goes by.

Re:My battery is bigger than yours! (1)

Have Brain Will Rent (1031664) | more than 2 years ago | (#41241703)

I just knew that living beside high voltage transmission lines would come in handy someday!

Re:My battery is bigger than yours! (0)

Anonymous Coward | more than 2 years ago | (#41245869)

The speed of this device is also related to the initial velocity of the projectile. Using a CO2 based paintball gun to fire your projectile and then accelerating it can easily in this size get 5000 mph. Using an explosive intitial run could easily get 8000 mph. At that speed projectiles tend to come apart in the air unless they are very hard.

Re:My battery is bigger than yours! (1)

PopeRatzo (965947) | more than 2 years ago | (#41239949)

Wonderful! And is it attached to a battery pack the size of a truck trailer?

So, I guess conceal/carry is out of the question.

Re:My battery is bigger than yours! (1)

drinkypoo (153816) | more than 2 years ago | (#41244217)

Wonderful! And is it attached to a battery pack the size of a truck trailer?

So, I guess conceal/carry is out of the question.

Except on the road, if you make an 18 wheeler your daily driver.

Mmmmm (3, Funny)

Seizurebleak (2020360) | more than 2 years ago | (#41239029)

I love the smell of toasted zergling in the morning.

Woop... (2, Interesting)

Anonymous Coward | more than 2 years ago | (#41239167)

TFA: Fortunately, he has no plans on developing it commercially, or on telling other people how to make one of their own.

Capacitors, em coils, pressure sensors... you pretty much already told us how to build it. Of course, anyone with an IQ above room temperature could have worked that out from the descriptions in the various games that employ similar weapons. I personally would have gone with something other than pressure sensors to trigger the next coil -- wear/tear, added drag, etc. -- but to each his own.

As far as producing it commercially? The US Navy is already working on that, thanks.

This guy has a history of making cool garage-project, working replicas, but it's nothing as innovative as all that. There's a reason soldiers are still carrying around powder-charged ammo instead of giant power packs and several pounds of coil.

Laser sight out the barrel (1)

Michael Woodhams (112247) | more than 2 years ago | (#41239453)

For even more 'awesome but impractical' bonus points, I suspect you could modify this so that the laser sight actually shines out of the barrel. Repurpose the mirror-flipping mechanism out of an old SLR camera.

The comments on that blog are whats wrong with USA (1)

viperidaenz (2515578) | more than 2 years ago | (#41239525)

One commenter states a 45 ACP round is much better.

It looks neat, but performance is unimpressive. 328 FPS is only about a third of the muzzle velocity of 45 ACP pistol ammo

I agree.
A reply to that comment

what is the weight of the projectile
it is slow, but if it is 3 X heavier than a 45 ACP than it would deliver the same power to the target

If it is 3X the mass and travels 1/3rd the speed, it carries 1/3rd the energy.

Won't somebody please teach the children science?

Re:The comments on that blog are whats wrong with (0)

Anonymous Coward | more than 2 years ago | (#41239685)

In some contexts, stopping power is measured by momentum transferred, not energy transferred. It is using "power" in the colloquial sense, not physics jargon sense.

Re:The comments on that blog are whats wrong with (0)

Anonymous Coward | more than 2 years ago | (#41239713)

Where I live they are too busy teaching the kids English and Creationism.

Re:The comments on that blog are whats wrong with (0)

Anonymous Coward | more than 2 years ago | (#41239871)

Also, it's a 22 caliber projectile made of steel (less dense than either lead or copper, which any schoolboy knows most bullets are made of). So at half the diameter, it should be 12 times the length to be 3x the volume -- and even longer for 3x the mass.

The ignorance, it burns.

Re:The comments on that blog are whats wrong with (1)

Sentrion (964745) | more than 2 years ago | (#41240099)

With 3X the mass and 1/3rd the speed it would have the same momentum. Granted, the power, as in energy, delivered would be less, but with a weapon you might be more concerned about momemtum. A small high-energy particle might pass completely through a target while doing minimal damage. But a larger particle with less energy might be able to do more damage, or at least have a greater chance of knocking the target down, often referred to as "stopping power". Consider a gun battle between two beligerents, and suppose one of the combatants shoots the other with a smaller bullet that passes quickly through their shoulder. Imagine that the impact slightly jolts the combatant, but they quickly recover their position and aim to hit the other combatant with a much larger bullet that might be moving much slower. The larger bullet may impact the combatant's shoulder in a manner identical to the first, but the impact from the larger bullet might have the affect of knocking the combatant off balance, perhaps to the floor. Penetration might not even be lethal depending on various factors, but being knocked off balance, on the ground, the second combatant is at much of a disadvantage if the first pursues the second for follow-up shots that keep him down and possibly end in fatality, such as a shot to the head, which is fatal even with a rubber slug.

Re:The comments on that blog are whats wrong with (1)

Antipater (2053064) | more than 2 years ago | (#41240539)

Everything you said is true. But don't get the idea that smaller, high-velocity bullets are useless - otherwise, we'd still be using 20mm musket balls. Bullets since the Minie ball in the American Civil War have been designed to offset their lack of stopping power with fragmentation and wounding effects - your hit through the shoulder isn't just going to zip in and out. It's going to zip in, shatter, then tear out, taking many times its volume in flesh with it. And the smaller, lighter ammo and easier recoil are also demonstrable benefits.

Re:The comments on that blog are whats wrong with (1)

wagnerrp (1305589) | more than 2 years ago | (#41243075)

That's why modern rifle rounds are unstable, but spin stabilized. Low weight and high velocity means they have good range and accuracy, as well as some ability to penetrate armor. Instability means when they are disrupted by some kind of resistance, like a human, they tend to yaw violently and then fragment. Technology to provide all the lethality of a hollow point bullet, but without violating the Geneva Convention.

Re:The comments on that blog are whats wrong with (1)

Dekker3D (989692) | more than 2 years ago | (#41240367)

A bit of research tells me that 45 ACP rounds are about 10-15 grams. The video says the railgun projectiles are 5.6 x 16 mm.. I'm assuming both are mm, then, which would mean a perfect cylinder would have 0.394 cm cubed of mass. Most steel seems to be about 7.5 gram per cm3, so that'd be about 3 grams.. a little less, because it's not a cylinder.

It has 1/5th the mass, and 1/3rd the velocity. Kinetic energy would be.. what. 1/75th?

These numbers seem excessive, so please correct me if I'm wrong. It's rather shocking that a pretty well designed, heavy coilgun only gives 1/75th the power of an average handgun. Especially since said handgun can probably unload its ammo into its target 5 times faster.

Re:The comments on that blog are whats wrong with (0)

Anonymous Coward | more than 2 years ago | (#41242447)

kinetic energy is proportional to mass times velocity squared. so 1/5 * 1/3 * 1/3 = 1/45, not 1/75. Dunno where you got 1/75.

Re:The comments on that blog are whats wrong with (1)

Dekker3D (989692) | more than 2 years ago | (#41243355)

Accidently squared the 1/5. Derp. Still a tiny number though.

Re:The comments on that blog are whats wrong with (1)

viperidaenz (2515578) | more than 2 years ago | (#41242491)

It's not excessive. The energy stored and released by the capacitors in this guys rail gun is nowhere near as much as the amount released by the gun powder in a bullet. Assuming those are 100uf 400V capacitors, you're talking about 1600J, a fair amount of that would be lost as heat in the internal resistance of the capacitor and the resistance of the coils. The projectile carries around 10 - 15J of energy.

Re:The comments on that blog are whats wrong with (0)

Anonymous Coward | more than 2 years ago | (#41243319)

It's a fucking coilgun.

It's not a railgun.
en.wikipedia.org/coilgun
en.wikipedia.org/railgun

Re:The comments on that blog are whats wrong with (1)

wagnerrp (1305589) | more than 2 years ago | (#41243105)

These numbers seem excessive, so please correct me if I'm wrong. It's rather shocking that a pretty well designed, heavy coilgun only gives 1/75th the power of an average handgun.

Coilguns only do a few percent efficiency. Out of a claimed 500J propellent energy from the caps, only some 15J or so were transferred to the projectile.

Don't let it overcharge... (1)

ProZachar (410739) | more than 2 years ago | (#41240049)

What do you mean, overcharge?

Offensive censorship (1)

GameboyRMH (1153867) | more than 2 years ago | (#41241603)

Had this guy released the plans I might not have looked at them, but since he offensively censored the information I went and learned all about coil guns.

Re:Offensive censorship (1)

cmwatford (2679257) | more than 2 years ago | (#41247109)

And thus his plan was complete.

So, how old is this guy? About thirteen? (0)

Anonymous Coward | more than 2 years ago | (#41243909)

Someone should tell him that a decent airsoft rifle will shoot a projectile further and have more impact energy than his home-made coilgun, and have the battery power to do that a few thousand times rather than a few dozen.

He's all like "OH LOOK AT THAT DENT IN MY WALL I MADE WITH MY COILGUN BECAUSE I COULDN'T HIT A WATERMELON AT THREE FEET!"

Yeah? I've got a similar dent in my wall. I slipped and slammed my elbow into it. Hurt like hell, and would apparently be just as powerful as your mighty weapon.

Now, I do enjoy the science aspect of electromagnetic weapons development, but I frankly get a bit embarrassed on behalf of people like this who try and paint it up as so hugely powerful when it's clearly nowhere near being so. Is it a cool looking gun? Sure. Is it a gauss rifle? Not even close. Is it a dangerous toy? Yeah, about as dangerous as an old school nerf gun - you could put someones eye out.

Is the creator a 13 year old boy? Well, apparently in some regards. And I posted AC because from my experience, so is a lot of mods.

iRail (1)

virgnarus (1949790) | more than 2 years ago | (#41247171)

I just took one look at the picture and thought the guy made it with 8 iPads. I felt a sigh of relief to know that no one would've been that stupid, but also paradoxically felt bummed that they weren't.

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