MV CoilMaster Mark1 CoilGun

The Weapon of the future, shooting steel bullets on pure electricity! This type of weapon is also referred to as coil gun or gauss gun.

I tried to get the Sci-fi / Unreal Tournament look.

 

After some experimenting at school we made a successful working coilgun with speeds up to 85 km/h, now this project is to make it more compact so you will be able to carry it around. Also more power and more speed!

The nozzle velocity is still very slow compared to a paintball marker or any other rifle, but the weight of the bullet makes sure it will still give quite a punch. (A paintball @ 300fps still only packs 15Joule)

It's still a hobby project and not perfected in any other way than the looks:)

 

specs:

 

Fully semi-automatic, up to 14 shots.
Capable of delivering over 18J kinetic energy, and speeds up to 110km/h! (42 gram projectiles).
Its a single stage gun, using a 8800uF(4×2200) capacitor bank with max 400v (704J).
Max shot efficiency is 2.8% but reaches almost 4% at lower voltages.

Charge time for 300v (12J kinetic energy 396J capacitor bank) is 8 seconds for the mains connection,
and when using the internal batteries about 90 seconds. It also has a Digital voltage display.

Coil overheat after 14 shots at 300v.
Total weight: 5 kilogram.
Total spend: ~~ 100 Euro
Construction time: ~~40 Hrs
Ammo type: 12 x 50 mm steel slugs 42 gram

 

clip size: 14

 

 

Used camera: Exilim EX-FH20 (bad audio good video)

 

And the movie:

 


A coilgun is basically a linear motor. a coil attracts a piece of steel, as soon as the steel piece is in the center of the coil the coil gets turned off. at this moment the projectile has already build its velocity and kinetic energy and keeps going.

A few pics:

 

Simple coilgun schematic:

 

My schematic (click to enlarge):

alt

 

Switches 1-3 are standard power switches, the 3 switches you see at the side of the gun. S4 is a micro switch located behind the trigger. The diodes I used can be any high speed type, I used the mur 860 from one of my teslacoils. They are just there to prevent that the capacitors charge negatively from the induction of the coil.

K1 and k2 are Relays with double contacts. The voltage regulator is used because I only had 5v relays, if you use 9v relays you won’t need the voltage regulator ic.

The photo flash charger I used is made for 6v and is from a large external flash unit, it pulls over 8 amps from the batteries.

 

The light bulb is used as a charging resistor, i am now using a 150W bulb, every higher wattage would decrease the charging time of the capacitors. (a 300W bulb would half the charge time and a 75W would double it).

 

A bulb is ideal as a charging resistor because it is made to dissipate large amounts of energy, plus its resistance decreases over time. when the charging current decreases (the capacitors getting fuller and fuller) the wire inside the bulb cools down, this causes the resistance to drop and that in turn increases the charging current again.

when you charge capacitors with a voltage source, it will charge fast in the beginning and very slow at the end (charges with an e-squire). by using a bulb as charge resistor you can more or less compensate for this.

150W bulb resistance hot: i=p/u =150/230 =0.65A, r=u/i =230/0.65 =354 Ohm
150W bulb resistance cold: = 15 Ohm

For the people who think I violated a few laws by making this, don’t worry. I talked to a police officer and he told me  that this files under the category of ballistic weapons (like bows and crossbows) because there is no gunpowder or explosion involved. So you won't need a license for any coilgun.
of course its illegal to walk with it loaded and ready on the street (like a crossbow), but if you would increase the power to that of a real firearm, would it still be legal?

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