Don't even act like you aren't impressed because now you too can fire magnetic accelerated pieces of metal from your backyard.
Don't even act like you aren't impressed because now you too can fire magnetic accelerated pieces of metal from your backyard.
someone should show that guy how to use a drill to make holes to use bolts to hold things together instead of c clamps..
C-clamps add rustic charm.
uh, I thought he said the projectile was aluminum... can someone explain to me how this magnetic gun is supposed to shoot an aluminum projectile?
That didn't look dangerous at all.
Robbie wrote: uh, I thought he said the projectile was aluminum... can someone explain to me how this magnetic gun is supposed to shoot an aluminum projectile?
Aluminum is actually a fairly commonly used material for the projectile in a railgun. It's complicated, but while not ferromagnetic aluminum DOES react to powerful magnetic fields: http://terpconnect.umd.edu/~wbreslyn/magnets/is-aluminium-magnetic.html
Robbie wrote: uh, I thought he said the projectile was aluminum... can someone explain to me how this magnetic gun is supposed to shoot an aluminum projectile?
The projectile doesnt have to be ferromagnetic, just conductive but aluminum is a poor choice in material because of the low melting point. If you notice in the video the gun just sprayed molten aluminum and no slug.
Robbie wrote: uh, I thought he said the projectile was aluminum... can someone explain to me how this magnetic gun is supposed to shoot an aluminum projectile?
The magnetic field is caused by the current running through the projectile, so it works with anything conductive.
echoechoecho wrote:Robbie wrote: uh, I thought he said the projectile was aluminum... can someone explain to me how this magnetic gun is supposed to shoot an aluminum projectile?The projectile doesnt have to be ferromagnetic, just conductive but aluminum is a poor choice in material because of the low melting point. If you notice in the video the gun just sprayed molten aluminum and no slug.
in this video they shoot some ballistic gel with it and catch the slug so its definitely not melting it
The edges of the projectile look pretty chewed up in that gel video. I can't help but thinking they would get better terminal results with a sabot round, but I didn't design a railgun, either, so I'll shut up.
They claim they like melting the aluminum cuz the molten spray reduces friction. That may be but I cannot help but think there's gotta be a better way, than calling that effect a "feature".
He's charging the bank of capacitors off of a bank of 50 9V batteries? That's 450V DC. I'd call that terrifying. 
https://youtu.be/dsYJhqOIB9U?t=66
I might have a new hero.
Very Cool!!!
In reply to Toyman01:
The capacitors just sitting there is what's terrifying.....
Very cool!
java230 wrote: In reply to Toyman01: The capacitors just sitting there is what's terrifying.....
I'd say that the massive aluminum bars used to connect them just sitting in the open where someone might touch them is more terrifying still. At least they learned how to drill holes and bolt things together after the first firing that blew every clamp off the setup...
Ashyukun wrote:java230 wrote: In reply to Toyman01: The capacitors just sitting there is what's terrifying.....I'd say that the massive aluminum bars used to connect them just sitting in the open where someone might touch them is more terrifying still. At least they learned how to drill holes and bolt things together after the first firing that blew every clamp off the setup...
the guy running the camera responded to one of my posts on facebook about this... he said they were so excited to see it fire that they just decided to clamp everything together quickly.. i told him they were idiots for not taking the 10 minutes it would have taken to drill a few holes and bolt the whole thing together..
The internet is full of people who will call you an idiot for doing something cool as a proof of concept. What you've done is teach them not to share the insanity and excitement of the first attempt, but instead wait until it's perfect.
Watch how much the cables jump when it's fired. Pretty sure that's mostly due to the huge self-induced magnetic pulse. That said, I can't help but wonder if it's all a joke. I don't know the inner workings of a rail gun, but I thought there had to be switching elements to selectively gate all that power just ahead of the projectile. Don't see any of that circuitry, which isn't trivial.
Keith Tanner wrote: The internet is full of people who will call you an idiot for doing something cool as a proof of concept. What you've done is teach them not to share the insanity and excitement of the first attempt, but instead wait until it's perfect.
You can usually shut down that type by asking how they did it on their project.
I took the active wing off my car because I got sick of the same conversation over and over again.
I watched the video with no sound (office!), but the shape of the projectile seems very specific. I wonder if they're basically throwing vaporized aluminum out the throat on the back as a propellant. It doesn't have a lot of velocity if you watch the "car door" and "ballistic gel" videos.
A longer 'barrel' would probably increase the velocity. This is cool stuff.
If you want to have 90% of the fun on 1% of the budget, build a potato cannon.
Robbie wrote: uh, I thought he said the projectile was aluminum... can someone explain to me how this magnetic gun is supposed to shoot an aluminum projectile?
Magnets don't stick to aluminum but they do "grab" it for lack of better words.
For a fun demo, go in kitchen, take aluminum foil roll out of box, stand on end, drop a neodymium magnet through it. https://www.youtube.com/embed/mdpWcU-nD3I
Just this in reverse:
That must be how eddy-current dynos work. My mind is a little blown right now.
Kenny_McCormic wrote:Robbie wrote: uh, I thought he said the projectile was aluminum... can someone explain to me how this magnetic gun is supposed to shoot an aluminum projectile?Magnets don't stick to aluminum but they do "grab" it for lack of better words. For a fun demo, go in kitchen, take aluminum foil roll out of box, stand on end, drop a neodymium magnet through it. https://www.youtube.com/embed/mdpWcU-nD3I
Funny. I had a stack of 1/2" neodymium magnets here on my desk and I just ran out to the garage and found a piece of copper pipe and dang if it doesn't fall through it slowly. Neato! I'm gonna go show the kids! 
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