E
Ethan
A couple years ago a buddy and I built a rail gun in the garage. The
goal was simply to see how fast we can make something move.
For anybody not familiar with this, it is a type of linear motor that
uses two parallel conducting rails and a conductor that slides along
them. When a large current is put through the rails the resulting
magnetic field creates a force that pushes the conductor along the
rails. In theory, extreemly high velicities can be achieved this way.
It worked reasonably well, however we finally ran into the limitation
of not having a good enough way to store the energy to be dumped into
the projectile. We were using a capacitor bank made up of the
capacitors from scrapped motor controllers. Bolting togethor 90 motor
controller cap banks gave us a 0.18F, 180V capacitor, so about 3kJ.
When you short it across the rails you get one hell of a lot of
current and the projectile conductor really goes. The best velocity
was between 200 and 300 mph.
The limitation was mostly due to not enough energy. I read somewhere
that a high power rifle slug can have up to about 6kJ of kinetic
energy, and we were only getting 30-40J of kinetic energy. (Our
efficiency was pretty low)
I have been meaning to dust the thing off and try again, but have not
been able to come up with a better energy source. I would like to be
able to dump better than 100kJ of electrical energy in about 1mS.
Does anybody have any ideas about how to do this? The most compact
way to store energy is chemically, so mabye there is some way to get
the energy out of a battery really quickly, or use an explosive to
push a magnet, like a homopolar motor, or some such thing.
If anyone has any ideas for an energy source I would love to hear
them.
Ethan
goal was simply to see how fast we can make something move.
For anybody not familiar with this, it is a type of linear motor that
uses two parallel conducting rails and a conductor that slides along
them. When a large current is put through the rails the resulting
magnetic field creates a force that pushes the conductor along the
rails. In theory, extreemly high velicities can be achieved this way.
It worked reasonably well, however we finally ran into the limitation
of not having a good enough way to store the energy to be dumped into
the projectile. We were using a capacitor bank made up of the
capacitors from scrapped motor controllers. Bolting togethor 90 motor
controller cap banks gave us a 0.18F, 180V capacitor, so about 3kJ.
When you short it across the rails you get one hell of a lot of
current and the projectile conductor really goes. The best velocity
was between 200 and 300 mph.
The limitation was mostly due to not enough energy. I read somewhere
that a high power rifle slug can have up to about 6kJ of kinetic
energy, and we were only getting 30-40J of kinetic energy. (Our
efficiency was pretty low)
I have been meaning to dust the thing off and try again, but have not
been able to come up with a better energy source. I would like to be
able to dump better than 100kJ of electrical energy in about 1mS.
Does anybody have any ideas about how to do this? The most compact
way to store energy is chemically, so mabye there is some way to get
the energy out of a battery really quickly, or use an explosive to
push a magnet, like a homopolar motor, or some such thing.
If anyone has any ideas for an energy source I would love to hear
them.
Ethan