I've decided on my crazy summer project, this is going to take a long time, and come in a ton of renditions until its a huge MAG.
I know PV your a science teacher, so maybe you'll point out flaws in what I'm doing and save me from electrocution here and there.
I'm working in autocad right now to draw up some preliminary plans, but for those who do NOT know what a MAG is...
A MAG is a magnetic accelerator gun,
...also known as, a Rail Gun. Its not a coil gun either. A coil gun pulls the shot out by Lorenz forces, a railgun uses Lorenz forces to launch the armature, as the armature is actually part of the circuit.
Here's a basic sketch of the physics behind it for you,
Huge amounts of current flow down the rail, this by the right hand rule, sets up a clockwise magnet field. The current then flows across the armature, and down the other rail. This makes one rail an anode, and one a cathode. On the second rail, the current is coming back and by the right hand rule sets up a counterclockwise magnetic field. This creates a magnet field that stacks up, and does not cancel, resulting in a magnetic field upwards away from the rails, or downwards and away. By the laws of physics then, the current (I) flows across the armature, the magnetic field (B) is perpendicular to that, and the force on the armature (F) is perpendicular to that. This applies all over the rails as well. Therefore the rails are going to have just as much force on them, as the armature. So its going to have to be pretty f'ing sturdy!
Thats the basics, I'm going to start small, very very small, and move upwards to a huge multi-kilojoule MAG by the end of the summer.
----First MAG----
Transformer from 110VAC to 24VAC, diode bridge to produce 24VDC. *
Up to one HUNDRED 3800uF 35V capacitors (don't ask why I have this
) *
Aluminum rails and armatures
Injection system for armature
Random crap I'm going to need to not get zapped
So I have my powersupply basically, and my capacitor bank for this small one. The calculation in the picture is for a 18,000 uF capacitor that I'm getting, well 2 of them. Each one at 250VDC will produce nearly 1.125KJ! I'm not going to use these yet, as it only takes around 16 joules to kill a person!
So for my small caps...
Energy = (.5) (Capacitance) (Voltage^2)
E = (.5) (.0038) (24^2)
E = 1.1 Joule
Yep, they're pretty small. Each capacitor I solder into parallel will add one joule to the system. Now thats not much, not much at all, so using these will most likely only allow me to launch pennys and such.
A very very rough calculation of what the boost in speed thru the railgun would be with lets say, 10 joules.
(kinetic energy) = (.5) (Mass) (Velocity ^ 2)
10 = .5 ( .00235 (mass of a penny!) ) V ^ 2
V = 92 m/s boost!
or
205 Miles per hour!
OR (for you brits)
329 Kilometers per hour!
And thats in addition to the injection speed. 10 Joules, thats all. But look at the math, when you use an incredibly light object (such as a penny), you wind up doubling the original kinetic energy due to the .5, then multiplying by a factor of 425!
So I'm going to look into (probably on ebay), buying some foot long peices of 1/4" square aluminum rod. This will make a very preliminary rail system. I'm thinking of trying some light metal marbles as well, but the need to keep contact with the rails might not be so great.
-----
MAJOR CONCERNS OF BUILDING A MAG.
Huge safety concern here guys, massive amounts of electricity released in tenths of a second. Easily one of the worst ways to die as well. Dont do this without alot of research and safety in your design. Its very easy to end up building a spot welder and or melting your entire railgun with one false fire. Also the rails themselves will vaporize with time due to the high amounts of current fired through them.
The armature has to be injected into the railgun, if it begins at rest, the forces will not break the static friction, and all the current will shoot thru a tiny localized spot on the rails. With two like materials, especially aluminum, they will spot weld and/or melt nearly instantly. With higher currents they may even turn to plasma.
Plasmalyzing of the armature may also occur, so don't fire it at your hand or pet. This should be sweet though, as apart from possibly rail damage, plasma is pretty
The design also has to be very sturdy or your rails will shoot apart from a huge amount of force. I will conduct many test shots with just injection to make sure the round won't stick, as well as other concerns. Most likely I will use copper rails (no welding possiblities), or brass or a combination for the final rails. Graphite is possibly the best armature, but for now, aluminum should work. The best rails would actually be silver plated copper, but I'm not rich.
The final designs injection will most likely be from a large air compressor tank, or simply Co2 from my regulator so that I may test different shot pressures. I'm going to need to get a good solenoid either way as pressure release from right behind the armature will lead to the best results.
As for pressure...
Pressure = Force / Area
Re-arrange it for what I want:
Force = Pressure * Area
The more pressure I can get with a larger area, will lead to the most force. 100 PSI of Co2 thru a 1/4" square would be...
100 * .25 * .25 = 6.25 Newtons.
Force also equals mass * acceleration
Set those equal, and lets say that the penny was 1/4" square and retained the same mass...
6.25 = .00235 * A
Acceleration = 2700 m/s/s!!!
That acceleration will lead to a very high injection velocity provided I can maintain that pressure either all the way through (probably won't, might not end well), or even just few inch track right before the MAG.
So, let the insane summer project of 2k7 begin.
Hehehhe I'm cackling already.
I know PV your a science teacher, so maybe you'll point out flaws in what I'm doing and save me from electrocution here and there.
I'm working in autocad right now to draw up some preliminary plans, but for those who do NOT know what a MAG is...
A MAG is a magnetic accelerator gun,
...also known as, a Rail Gun. Its not a coil gun either. A coil gun pulls the shot out by Lorenz forces, a railgun uses Lorenz forces to launch the armature, as the armature is actually part of the circuit.
Here's a basic sketch of the physics behind it for you,
Huge amounts of current flow down the rail, this by the right hand rule, sets up a clockwise magnet field. The current then flows across the armature, and down the other rail. This makes one rail an anode, and one a cathode. On the second rail, the current is coming back and by the right hand rule sets up a counterclockwise magnetic field. This creates a magnet field that stacks up, and does not cancel, resulting in a magnetic field upwards away from the rails, or downwards and away. By the laws of physics then, the current (I) flows across the armature, the magnetic field (B) is perpendicular to that, and the force on the armature (F) is perpendicular to that. This applies all over the rails as well. Therefore the rails are going to have just as much force on them, as the armature. So its going to have to be pretty f'ing sturdy!
Thats the basics, I'm going to start small, very very small, and move upwards to a huge multi-kilojoule MAG by the end of the summer.
----First MAG----
Transformer from 110VAC to 24VAC, diode bridge to produce 24VDC. *
Up to one HUNDRED 3800uF 35V capacitors (don't ask why I have this
) *Aluminum rails and armatures
Injection system for armature
Random crap I'm going to need to not get zapped
So I have my powersupply basically, and my capacitor bank for this small one. The calculation in the picture is for a 18,000 uF capacitor that I'm getting, well 2 of them. Each one at 250VDC will produce nearly 1.125KJ! I'm not going to use these yet, as it only takes around 16 joules to kill a person!
So for my small caps...
Energy = (.5) (Capacitance) (Voltage^2)
E = (.5) (.0038) (24^2)
E = 1.1 Joule
Yep, they're pretty small. Each capacitor I solder into parallel will add one joule to the system. Now thats not much, not much at all, so using these will most likely only allow me to launch pennys and such.
A very very rough calculation of what the boost in speed thru the railgun would be with lets say, 10 joules.
(kinetic energy) = (.5) (Mass) (Velocity ^ 2)
10 = .5 ( .00235 (mass of a penny!) ) V ^ 2
V = 92 m/s boost!
or
205 Miles per hour!
OR (for you brits)
329 Kilometers per hour!
And thats in addition to the injection speed. 10 Joules, thats all. But look at the math, when you use an incredibly light object (such as a penny), you wind up doubling the original kinetic energy due to the .5, then multiplying by a factor of 425!
So I'm going to look into (probably on ebay), buying some foot long peices of 1/4" square aluminum rod. This will make a very preliminary rail system. I'm thinking of trying some light metal marbles as well, but the need to keep contact with the rails might not be so great.
-----
MAJOR CONCERNS OF BUILDING A MAG.
Huge safety concern here guys, massive amounts of electricity released in tenths of a second. Easily one of the worst ways to die as well. Dont do this without alot of research and safety in your design. Its very easy to end up building a spot welder and or melting your entire railgun with one false fire. Also the rails themselves will vaporize with time due to the high amounts of current fired through them.
The armature has to be injected into the railgun, if it begins at rest, the forces will not break the static friction, and all the current will shoot thru a tiny localized spot on the rails. With two like materials, especially aluminum, they will spot weld and/or melt nearly instantly. With higher currents they may even turn to plasma.
Plasmalyzing of the armature may also occur, so don't fire it at your hand or pet. This should be sweet though, as apart from possibly rail damage, plasma is pretty
The design also has to be very sturdy or your rails will shoot apart from a huge amount of force. I will conduct many test shots with just injection to make sure the round won't stick, as well as other concerns. Most likely I will use copper rails (no welding possiblities), or brass or a combination for the final rails. Graphite is possibly the best armature, but for now, aluminum should work. The best rails would actually be silver plated copper, but I'm not rich.
The final designs injection will most likely be from a large air compressor tank, or simply Co2 from my regulator so that I may test different shot pressures. I'm going to need to get a good solenoid either way as pressure release from right behind the armature will lead to the best results.
As for pressure...
Pressure = Force / Area
Re-arrange it for what I want:
Force = Pressure * Area
The more pressure I can get with a larger area, will lead to the most force. 100 PSI of Co2 thru a 1/4" square would be...
100 * .25 * .25 = 6.25 Newtons.
Force also equals mass * acceleration
Set those equal, and lets say that the penny was 1/4" square and retained the same mass...
6.25 = .00235 * A
Acceleration = 2700 m/s/s!!!
That acceleration will lead to a very high injection velocity provided I can maintain that pressure either all the way through (probably won't, might not end well), or even just few inch track right before the MAG.
So, let the insane summer project of 2k7 begin.
Hehehhe I'm cackling already.
