Post/Author/DateTime	Post
#1 Ragnar_Lodbrok Jan 21, 2010 21:24:21	A friend and I are currently designing a coilgun (designed in a rifle-esque format). We've figured out some of the main issues, such as the trigger (current design has it completing the circuit to power up the coils while pushing the tungsten slug into the barrel) and a clip (plastic case using springs to push the slug into place for the next shot when the trigger is relaxed), and we can probably put together a functional version, but I've considered marketing it to the military (yeah, I know, they've probably already got prototypes, and this will thus fail). Thus, the firing rate of a handgun won't do. I need some ideas on how to get it to a semi-automatic firing rate if possible (I'm fairly certain that automatic weapons require the explosion of the gunpowder to achieve that rate of fire, so I doubt that an automatic coilgun is currently feasible). Otherwise, it may be a good sniper rifle. A currently unsolvable issue is a more efficient power source, which will probably keep the project on hiatus after the completion of the prototype. Oh, before I forget: planned power source is a car battery, current design also includes an aluminum barrel and steel coils.
#2 Escef Jan 21, 2010 21:27:46	Will cell-phone batteries work instead? Chain a few together with a transformer if needed. They're compact and light, and the weight of your power supply can now be distributed across the user's body.
#3 Ragnar_Lodbrok Jan 21, 2010 21:33:12	Will cell-phone batteries work instead? Chain a few together with a transformer if needed. They're compact and light, and the weight of your power supply can now be distributed across the user's body. ... Never thought of that. That should work, since the main reason for a car battery was that they can be recharged and store enough power (or so I think, but since I can't test it yet I can't be 100% certain).
#4 toastedamphibian Jan 21, 2010 21:53:51	As far as I know, cell phone batteries, as with most modern batteries, do not release energy very quickly with any type of efficency. What is the practicle use of your coil gun? How is it better, hypothetically, than a musket, much less a modern rifle? What kind of rail system have you setup that isnt gonig to get extreemly hot or break under the pressure of a supersonic projectile, or are you planning on weaponisng it at subsonic speed? What is your target weight, will it be easily carrayble by a soldier and efficent to aim? If I am not mistaken, coil guns work by creating a magnetic field at vary points of a coil in sequence to push a slug along a rail, yes? If so, fiering another slug before your first slug has exited would decrese the speed of the second shot as it gets repulsed by the fields infront of it as well as thoughes behind, would it not? Thus the limit of your rate of fire may well be a function of the length of your rail and the timing of your magnets, not your clip mechanisim. I was mistaken. It pulls them, not pushes. So firing a second slug before your first clears would disrupt your first. Anyways, the lack of a "firing pin" type mechansism should really make the clip quite simple, you shouldnt need anything more than a stiff spring. (So long as your spring is not taught enough to hold your slugs, and your coil is not strong enough or on for long enough to pull the second slug behind the first. I thought most such designs depended on capacitors to make up for the slow yeild of the batteries. I would think the time it takes your capacitor to charge would overshadow the speed of a spring clip. (Mabey in a freezing cold vacum and constructed with superconducters it could be an efficent weapon.)
#5 Escef Jan 21, 2010 22:03:09	If I am not mistaken, coil guns work by creating a magnetic field at vary points of a coil in sequence to push a slug along a rail, yes? You seem to have merged the concepts of coil gun and rail gun. A coil gun operates by using a series of magnetic coils to accelerate a projectile. A rail gun runs a current through a pair of conductive rails to accelerate a projectile along the rails. The barrel of a coil gun need not be conductive itself, so long as it does not insulate. As for the stresses on the barrel from a supersonic projectile, do you really think it would be any worse than the stress on a modern ballistic weapon? You know, an item that not only launches a super sonic projectile, but also uses an explosive to accomplish the feat?
#6 toastedamphibian Jan 21, 2010 22:10:13	You seem to have merged the concepts of coil gun and rail gun. A coil gun operates by using a series of magnetic coils to accelerate a projectile. A rail gun runs a current through a pair of conductive rails to accelerate a projectile along the rails. (Too slow. I already fixed that.) The barrel of a coil gun need not be conductive itself, so long as it does not insulate. As for the stresses on the barrel from a supersonic projectile, do you really think it would be any worse than the stress on a modern ballistic weapon? You know, an item that not only launches a super sonic projectile, but also uses an explosive to accomplish the feat? Nope. But stronger barrel implies more points of contact, implies more friction, implies more batteries you have to strap onto your soldier. All true of bullets I suppose, but gunpowder isnt exactly lacking in oomph. Batteries, on the other hand, are.
#7 Escef Jan 21, 2010 22:17:50	But stronger barrel implies more points of contact, implies more friction, implies more batteries you have to strap onto your soldier. You seem to have missed my point. YOU DON'T NEED A BARREL ANY MORE DURABLE THAN THAT OF A MODERN BALLISTIC WEAPON. Point of fact, you can probably get by with a less durable barrel, because it does not need to be able to deal with the kinetic force and heat resultant from the powder charge of a modern cartridge.
#8 toastedamphibian Jan 21, 2010 22:28:13	And, you missed my point: "Do you have a design for your barrel that will be efficent for its purpose and still durable enough?" Rifle barrel and Coil gun barrel need have little in common, aside from not breaking when used and guiding their projectiles down the desired path.
#9 Ragnar_Lodbrok Jan 21, 2010 22:37:15	As far as I know, cell phone batteries, as with most modern batteries, do not release energy very quickly with any type of efficency. What is the practicle use of your coil gun? How is it better, hypothetically, than a musket, much less a modern rifle? What kind of rail system have you setup that isnt gonig to get extreemly hot or break under the pressure of a supersonic projectile, or are you planning on weaponisng it at subsonic speed? What is your target weight, will it be easily carrayble by a soldier and efficent to aim? I thought most such designs depended on capacitors to make up for the slow yeild of the batteries. I would think the time it takes your capacitor to charge would overshadow the speed of a spring clip. (Mabey in a freezing cold vacum and constructed with superconducters it could be an efficent weapon.) Yeah, the power release has been the biggest concern, so currently, the design is being modified for many cell phone batteries. A coil gun doesn't make much noise and (as far as I know) has little to no kickback, so it would probably be great for, say, snipers. It may just turn out to be just a more expensive, less effective rifle. The weight of the gun itself isn't likely to be too bad (aluminum barrel, plastic case, wiring, coils, and cell phone batteries. Each component is lightweight. Tungsten is a pretty dense metal, if target weight refers to the weight of the projectile, thus, a relatively small slug would have a relatively large mass). Aiming shouldn't be much different than a typical rifle. Hadn't thought of capacitators. I'll want to look into those. The barrel design I have in mind is basically just unrifled aluminum (due to the weight and high melting point), since ideally the magnets will be suspending the slug away from the inside of the barrel.
#10 Escef Jan 21, 2010 22:47:18	And, you missed my point: "Do you have a design for your barrel that will be efficent for its purpose and still durable enough?" That's a question, not a point. You make a LOT of assumptions. I don't profess to be an expert in the fields of personal firearms or electronics. But I do have some experience with firearms and have friends who have made coil guns (yes, they have a kick).
#11 toastedamphibian Jan 21, 2010 22:57:13	That's a question, not a point. You make a LOT of assumptions. I don't profess to be an expert in the fields of personal firearms or electronics. But I do have some experience with firearms and have friends who have made coil guns (yes, they have a kick). Yes, it was a question, see: "What kind of rail system have you setup that isnt gonig to get extreemly hot or break under the pressure of a supersonic projectile, or are you planning on weaponisng it at subsonic speed"? If your coils are inside the barrel, wouldn't your slug hit them? Also, won't you loose long range accuracy by not rifling your barrel in some way?
#12 Escef Jan 21, 2010 23:04:18	Yes, it was a question, see: "What kind of rail system have you setup that isnt gonig to get extreemly hot or break under the pressure of a supersonic projectile, or are you planning on weaponisng it at subsonic speed"? images.google.com/images?hl=en&safe=off&...
#13 toastedamphibian Jan 21, 2010 23:52:48	Why would I click on a google image search link with "safe search" turned off? Why would you even post such a thing? Linking to pages with nudity is against CoC I belive. I suppose its possible you didn;t get any 'objectionable' results on your first page, but still.
#14 Escef Jan 22, 2010 0:25:47	Why would I click on a google image search link with "safe search" turned off? Why would you even post such a thing? Linking to pages with nudity is against CoC I belive. I suppose its possible you didn;t get any 'objectionable' results on your first page, but still. Report me if you honestly think I'm linking to nudity.
#15 toastedamphibian Jan 22, 2010 0:29:01	'tis not how I roll. Still not gonna click your weird link.
#16 darkspartan Jan 22, 2010 1:09:19	@TA: I had to get through eight or nine pages before the first image with a woman in it was shown. That said, I would consider copper coils, not steel. Especially if you're going to use a steel barrel. High-test ceramic is expensive. As far as power sources, you'll either need a number of large caps or a very quick-release battery, neither of which are particularly effective, either in terms of power transfer or weight. Using a liquid cell is right out. Too much chance of heating or breakage, and then your "soldier" will have far more immediate issues than the Enemy. That said, your design should be primarily motivated by it's intended use. If you're planning for a sniper weapon, then you'll most definitely want a long barrel made out of something other than what the barrel is made of. Copper is the usual metal of choice as stated above. It's also lighter and more compact. Aluminum isn't reall great for weapons frames: It's low melting point compared to steel also makes for issues. The firing process will generate substantial amounts of heat, even without gunpowder, the speed of the projectile will generate yet more. If you're planning on weaponizing it at sub-sonic speeds, you can limit(not eliminate) the sound and kick of the weapon. For a supersonic round, Sir issac Newton is going to bite you a lot harder, and there will be a nice report. Sonic Booms are fun. Just remember, for every action, there is an equal and opposite reaction. -Sarena
#17 Escef Jan 22, 2010 2:14:14	On coil guns having a kick. One of my friends who made one did not expect it to have a kick. He had the gun bolted to a small table when he fired it. Not only did he launch a projectile with surprising velocity, the kick from the coil gun also blew the table over. Just as the coils move the projectile forward, the coils pull themselves in the opposite direction. In fact, if you securely plug the barrel of a coil gun there is a good chance that when fired the gun will go flying away from the obstruction.
#18 zombie_babies Jan 22, 2010 9:41:16	If you're lookin' to make a sniper weapon, subsonic is right out.  You need speed to not only achieve distance, but to aid in maintaining accuracy.
#19 brianusa Jan 22, 2010 10:14:56	On the subject of capacitors, kiddies... Safety Guidelines for High Voltage and/or Line Powered Equipment: www.repairfaq.org/sam/safety.htm Consumer electronic equipment like TVs, computer monitors, microwave ovens, and electronic flash units, use voltages at power levels that are potentially lethal. Even more so for industrial equipment like lasers and anything else that is either connected to the power line, or uses or generates high voltage. Normally, these devices are safely enclosed to prevent accidental contact. However, when troubleshooting, testing, making adjustments, and during repair procedures, the cabinet will likely be open and/or safety interlocks may be defeated. Home-built or modified equipment, despite all warnings and recommendations to the contrary - could exist in this state for extended periods of time - or indefinitely. Depending on overall conditions and your general state of health, there is a wide variation of voltage, current, and total energy levels that can kill. Electronic flash units and strobe lights, and pulsed lasers have large energy storage capacitors which alone can deliver a lethal charge - long after the power has been removed. This applies to some extent even to those little disposable pocket cameras with flash which look so innocent being powered from a single 1.5 V AA battery. Don't be fooled - they are designed without any bleeder so the flash can be ready for use without draining the battery!
#20 Escef Jan 22, 2010 15:53:17	Holy crap, Brian said something coherent! The end is nigh!
#21 boraxe Jan 25, 2010 8:59:02	Holy crap, Brian said something coherent! The end is nigh! I assume he posted this to the wrong thread. It was probably meant as a reponse to a thread like "Do you like dogs?" or something.
#22 death_isthe_begining Jan 25, 2010 9:51:32	He seems very coherent when it come to math and similar subjects.
#23 boraxe Jan 25, 2010 10:16:11	He seems very coherent when it come to math and similar subjects. So you're saying he's Rain Man?
#24 death_isthe_begining Jan 25, 2010 10:29:42	He seems very coherent when it come to math and similar subjects. So you're saying he's Rain Man? More like the guy who made flubber. He is incrediblely scatterbrained at most times, but it is possible(though very difficult) to understand him.