Magnetic Munition
razorbud, Thu May 03 2007, 03:07PMHi
I was wondering if anyone hs thought about using a magnetic bullet in a coil gun? I was thinking about it the other day and wondered if you could pulse the coils twice, the first pulse is the same as a normal non magnetic bullet coil gun pulse, cutting off before the fied reverses and you get suck back. The second would be when half of the bullet is out of the other end of the coil to give it another push?
Wondering what you guys would think of that?
Re: Magnetic Munition
FastMHz, Thu May 03 2007, 04:30PM
I've never attempted to launch a magnetic projectile....if I can somehow shape one of my magnets into a round slug that'll fit my CG I'll give it a go.
FastMHz, Thu May 03 2007, 04:30PM
I've never attempted to launch a magnetic projectile....if I can somehow shape one of my magnets into a round slug that'll fit my CG I'll give it a go.
Re: Magnetic Munition
razorbud, Thu May 03 2007, 04:52PM
i was thinking of more along the line of a slug shaped projectile.
It would be relatively easy to turn one into a magnet by just stoking the slug with a hard magnet in on direction lots of times.
razorbud, Thu May 03 2007, 04:52PM
i was thinking of more along the line of a slug shaped projectile.
It would be relatively easy to turn one into a magnet by just stoking the slug with a hard magnet in on direction lots of times.
Re: Magnetic Munition
Bjørn, Thu May 03 2007, 06:54PM
If your projectile can be magnetized that easy, what do you think will happen when it is placed in a magnetic field that is 1000 times stronger in the coil gun?
Bjørn, Thu May 03 2007, 06:54PM
If your projectile can be magnetized that easy, what do you think will happen when it is placed in a magnetic field that is 1000 times stronger in the coil gun?
Re: Magnetic Munition
Electroholic, Thu May 03 2007, 07:07PM
if you can magnitize your projectile with a strong magnet, what makes you think that your coil won't demagnetize or magnetize it the other way when you fire the coil gun.
Electroholic, Thu May 03 2007, 07:07PM
if you can magnitize your projectile with a strong magnet, what makes you think that your coil won't demagnetize or magnetize it the other way when you fire the coil gun.
Re: Magnetic Munition
Effilcdar, Thu May 03 2007, 10:27PM
These would seem to be your best bet
Ebay #
160109966236 Large but powerfull
160110001500 small but cheap
250109710446 still a little large
110120399493 this seems to be a good size
Neodymium resists demagnetization but its brittle and light compare to other balistic materials.
Keep in mind if you want to try somthing like how many of the magnets will be available for sale. It would be very regretable if you were to break your last magnet and find that you can't find more the same size.
Effilcdar, Thu May 03 2007, 10:27PM
These would seem to be your best bet
Ebay #
160109966236 Large but powerfull
160110001500 small but cheap
250109710446 still a little large
110120399493 this seems to be a good size
Neodymium resists demagnetization but its brittle and light compare to other balistic materials.
Keep in mind if you want to try somthing like how many of the magnets will be available for sale. It would be very regretable if you were to break your last magnet and find that you can't find more the same size.
Re: Magnetic Munition
razorbud, Thu May 03 2007, 10:43PM
I do electronic and electrical engineering at university and they use magnetized poles in large solenoids.
The stroking method only works for soft magnetic materials, a good material would be a hard magnetic slug.
razorbud, Thu May 03 2007, 10:43PM
I do electronic and electrical engineering at university and they use magnetized poles in large solenoids.
The stroking method only works for soft magnetic materials, a good material would be a hard magnetic slug.
Re: Magnetic Munition
Electroholic, Thu May 03 2007, 11:37PM
Neodymium magnets resists demagnetization? you sure?
a solenoid is not a coil gun. at least not the ones we play with around here.
heres another link
Electroholic, Thu May 03 2007, 11:37PM
Neodymium magnets resists demagnetization? you sure?
a solenoid is not a coil gun. at least not the ones we play with around here.
heres another link
Re: Magnetic Munition
plur, Sun Jul 08 2007, 06:23PM
hi iam new..... any way ive been doing tests with some thing simlar but instead of a magnetic bullet ive been useing a steel bb and crushed ceramic magnets pack down in the base of the barral, the disanct the bb tavals has gone from (my frist coil gun) about a foot to about 10 - 15 feet with no other ajustments to the gun but not evry shot is relable some times it take a few pules for it to fire
plur, Sun Jul 08 2007, 06:23PM
hi iam new..... any way ive been doing tests with some thing simlar but instead of a magnetic bullet ive been useing a steel bb and crushed ceramic magnets pack down in the base of the barral, the disanct the bb tavals has gone from (my frist coil gun) about a foot to about 10 - 15 feet with no other ajustments to the gun but not evry shot is relable some times it take a few pules for it to fire
Re: Magnetic Munition
Dalus, Sun Jul 08 2007, 07:09PM
I used magnets from a old scsi hard drive on both sides of the coil and found that the efficiency increases. One explanation is that the field from the coil gets confined in the center of the coil by the external magnets.
Dalus, Sun Jul 08 2007, 07:09PM
plur wrote ...
hi iam new..... any way ive been doing tests with some thing simlar but instead of a magnetic bullet ive been useing a steel bb and crushed ceramic magnets pack down in the base of the barral, the disanct the bb tavals has gone from (my frist coil gun) about a foot to about 10 - 15 feet with no other ajustments to the gun but not evry shot is relable some times it take a few pules for it to fire
hi iam new..... any way ive been doing tests with some thing simlar but instead of a magnetic bullet ive been useing a steel bb and crushed ceramic magnets pack down in the base of the barral, the disanct the bb tavals has gone from (my frist coil gun) about a foot to about 10 - 15 feet with no other ajustments to the gun but not evry shot is relable some times it take a few pules for it to fire
I used magnets from a old scsi hard drive on both sides of the coil and found that the efficiency increases. One explanation is that the field from the coil gets confined in the center of the coil by the external magnets.
Re: Magnetic Munition
dingo27, Sat Jul 14 2007, 05:14PM
I was also thinking about this, but never had tube to test it. I have a magnet from Bicycle Computer (tachometer), which is perfectly round, and I also have bigger magnet from some russian speaker, which is little weakess than smaller one. I can place foto if you want, it is about 5 and 13mm diameter. But how the hell you want to be sure it´ll be in right direction, when you fire?
And... these magnets are made of something silver, maybe neodymium...
dingo27, Sat Jul 14 2007, 05:14PM
I was also thinking about this, but never had tube to test it. I have a magnet from Bicycle Computer (tachometer), which is perfectly round, and I also have bigger magnet from some russian speaker, which is little weakess than smaller one. I can place foto if you want, it is about 5 and 13mm diameter. But how the hell you want to be sure it´ll be in right direction, when you fire?
And... these magnets are made of something silver, maybe neodymium...
Re: Magnetic Munition
Myke, Sat Jul 14 2007, 06:58PM
You could use a compass to see what direction it is facing in and I'm 99% sure that the magnet is a rare earth super neodymium magnet.
Myke, Sat Jul 14 2007, 06:58PM
You could use a compass to see what direction it is facing in and I'm 99% sure that the magnet is a rare earth super neodymium magnet.
Re: Magnetic Munition
Firnagzen, Sun Jul 15 2007, 03:57AM
If you want to use neodymium magnets, I think you could coat it with some epoxy resin, to absorb part of the force and keep the shards from flying everywhere. The magnet will probably break regardless, but at least there won't be shrapnel.
Firnagzen, Sun Jul 15 2007, 03:57AM
If you want to use neodymium magnets, I think you could coat it with some epoxy resin, to absorb part of the force and keep the shards from flying everywhere. The magnet will probably break regardless, but at least there won't be shrapnel.
Re: Magnetic Munition
..., Sun Jul 15 2007, 05:05AM
Using a magnet for a small coil might help, but for anything that would have an output worth building the fields produced by the coil will be orders of magnitude greater than that of the magnet, and actually can end up remagnetizing it.
..., Sun Jul 15 2007, 05:05AM
Using a magnet for a small coil might help, but for anything that would have an output worth building the fields produced by the coil will be orders of magnitude greater than that of the magnet, and actually can end up remagnetizing it.
Re: Magnetic Munition
Dr. Shark, Mon Jul 16 2007, 10:40AM
I don't think so. A well-designed coilgun should avoid saturating the projectile, and even a not-so-well designd one shouln't saturate the projectile by orders of magnitude!
A nice side-effect of this permanent magnet coilgun would be that fact that you could "push" projectiles instead of "sucking" them, therefore avoiding the pulse-shaping trial and error to avoid suck-back.
Regarding the magnets: For gods sake, just look at any of the Wondermagnets-whatever web shops or even on eBay. There are lots of places selling cylindrical magnets, even I have 10s flying around even though it never occured to me they could be used for a coilgun.
Dr. Shark, Mon Jul 16 2007, 10:40AM
I don't think so. A well-designed coilgun should avoid saturating the projectile, and even a not-so-well designd one shouln't saturate the projectile by orders of magnitude!
A nice side-effect of this permanent magnet coilgun would be that fact that you could "push" projectiles instead of "sucking" them, therefore avoiding the pulse-shaping trial and error to avoid suck-back.
Regarding the magnets: For gods sake, just look at any of the Wondermagnets-whatever web shops or even on eBay. There are lots of places selling cylindrical magnets, even I have 10s flying around even though it never occured to me they could be used for a coilgun.
Re: Magnetic Munition
Marko, Mon Jul 16 2007, 05:14PM
Joe, you can ''push'' normal soft iron very well.
Once it is magnetized by coil's field, it will not be much different from magnet. Maximum flux density (2,2T) is also close to what neo magnet achieves.
In a multistage design, each coil is to be situated with opposite polarity than last one, so it uses the current magnetization of the projectile to accelerate and reverses it in process.
Next coil does the same but vice-versa. Not much different from a transformer or motor operation.
Ideally you could use unlimited number of stages as long as you assure each coil gives equal volt-seconds to the projectile (which is difficult) to assure that projectile doesn't walk into saturation.
Only problem is that with such a small max flux density, energy that can be transferred to the projectile in each stage is very low.
This was my understanding at least, and I think magnet would not do much except introduce large remanence losses. What I considered ideal reluctance projectile is soft material with highest possible saturation B.
Marko, Mon Jul 16 2007, 05:14PM
A nice side-effect of this permanent magnet coilgun would be that fact that you could "push" projectiles
Joe, you can ''push'' normal soft iron very well.
Once it is magnetized by coil's field, it will not be much different from magnet. Maximum flux density (2,2T) is also close to what neo magnet achieves.
In a multistage design, each coil is to be situated with opposite polarity than last one, so it uses the current magnetization of the projectile to accelerate and reverses it in process.
Next coil does the same but vice-versa. Not much different from a transformer or motor operation.
Ideally you could use unlimited number of stages as long as you assure each coil gives equal volt-seconds to the projectile (which is difficult) to assure that projectile doesn't walk into saturation.
Only problem is that with such a small max flux density, energy that can be transferred to the projectile in each stage is very low.
This was my understanding at least, and I think magnet would not do much except introduce large remanence losses. What I considered ideal reluctance projectile is soft material with highest possible saturation B.
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