[EMP-3A] [EMP-2A] [EMP-1A]

First high powered launch accidentally left this 5" aluminum disk deep in the roof boards of the garage!	Very strong magnetic pulses can do strange things to aluminum disks!	Latest project, electrolytic powered!

Since I have many EMP launcher projects, I have come up with a naming scheme that I will use:

EMP-1A-RIPS-1000 (example)

I have a separate page detailing theories and definitions of the concepts in use here. Also 3D models and animations. Check it out if you want to learn more about different styles of coilguns, how they work, and some good links to other informative sites. CLICK HERE

On to the weapons of magnetic destruction! 

EMP-3A

(my current project)

 ID Code: EMP-3A-LIES-3400

Current status: Completed & Operational

	I purchased a used lot of 13 caps off ebay.		Large SCR modules, stud type SCR, and rectifier diode. I was going to use the stud mount - but went ahead with the larger ones for this project.
	They are Cornell Dubilier 9,100µF 250V rated electrolytics.		The mostly completed launcher assembly. Caps, copper bus bars (1/4" thick), SCR's, and diodes.  Note: the final assembly utilized 4 caps banks in series, not 3.
	Large (wide) terminals usually indicate the cap is meant to surge a lot of current.		The aftermath of a ~750V shot. The launching coil arced through the disk and boom! No worry though, it was just a test coil.
	Here is a simplified schematic of the launcher.		Here is a schematic of the control box. It has provisions for 12V battery power or AC power, and a variable AC or DC output up to about 280VAC or 750VDC.
Movie clips of the launcher working:		Making coils:
	640x480 WMV 4.7MB First day of testing, see the self-destructive 1.5kJ shot.		I chose 1/2" thick Lexan since I had a few pieces of it. I also cut out a spacer with a hole saw out of thinner Lexan and recessed a spot in the middle for it so it will be the perfect thickness of the wire.
	640x480 WMV 18MB A longer clip showing 4 different launches including the above video, all on the first day of experimenting.		On the underside I cut a channel for the 'return wire'. Using a dremel I also rounded the edges where the wire will come up through the hole in the center.
	640x480 WMV 10MB Multiple low power shots with new coil and aluminum disk (300J and less). New chronograph measured velocities up to 67fps.		Here I am winding the coil, with another piece of 1/2" Lexan sandwiching the wire in the middle. There is epoxy smeared over the inner surfaces, and the coil is wound very tightly using alot of pressure.
	640x480 WMV 6.8MB New dual layer coil. Horizontal shot into yard, 1.4kJ and 210fps on the chronograph.		Instead of using a washer and marking how big the coil is to be I just bolted the projectile right to it. As soon as I see the winding around the outside of the projectile I stop winding.
	640x480 WMV 8.4MB Launching vertically into the sky and over some trees with about 850J (the highest I could go and still get the disk to appear on the video). Several shots.

     About:

This project was started in Spring of 2006. I had taken a several year break from working on any HV / EMP project. In that time I was changing jobs, getting married, and buying a house. Early in 2006 I found a forum online for HV enthusiasts 4HV.org and it sparked my interest once again. With renewed ambition and the help of 4HV.org I set out to design a more portable, electrolytic-powered, coilgun. Unlike EMP-2A which used a capacitor that weighed around 100 lbs and required nearly 10,000V to charge it, this new project will be portable and easier/safer to control. 

So far I have only done some preliminary testing with some quickly made test coils that didnt survive very long. There a huge improvements coming yet this year... Update: As seen in the pics I have made some new coils and tried different projectiles like the smaller thicker aluminum slugs and getting much better performance! The latest coil has held up to many shots at and over 1kJ.

My goals are to study and experiment to reach greater efficiencies, velocities, and energy. Hopefully I will be able to take enough information away from this project to build a more compact EMP pistol, and riffle model.

Here is a snapshot of an Excel spreadsheet I made to log velocities and efficiencies. At this time it is not 100% accurate as the projectile weight is an estimate and could be up to about +/- 10 grams. Also, there has been some inconsistency with my chronograph and I am going to set it up a little better with some direct light to make sure the results are correct. But this is what I have so far:

EMP-2A

EMP-2A was our first big success with EMP powered launchers. At the time (1999) I was still in college (DeVry) and had some friends participating in the project (Chris C., Joe M.) who were classmates as well. 

 ID Code: EMP-2A-LIPG-6000

Current status: Completed & decommissioned

 We then decided to take things outside...

Here are a couple more 5" hard drive disks (aluminum) that we used. The magnetic pulse is so great that the disk warps under nothing more than the resistance of air! Also note that 90% of the acceleration happens in the first 3" as the disk is repelled from the coil. We determined this by placing various non-conductive spacers so that the disk didn't sit right next to the coil, but a few inches above it. When we fired the launcher, it flew only a few feet in the air as opposed to the 100 plus feet we were getting.

The disk on the right is very interestingly distorted. Our first launch coil was 12AWG and not strong enough to hold up under the huge magnetic forces. The coil itself began to distort itself, then with one fairly high powered launch (around 2-4kJ if I remember correctly) the coil almost exploded and sent the disk spinning violently in the air making a loud buzzing noise as it spun. Despite all this, the disk still managed to go about as high as a large tree nearby and ended up landing over a hundred feet away in a field.

	Here, our first launching coil is distorting under the magnetic field. Note that it is 'kinking'.
	The coil finally gave way, not that I expected our duck tape setup to hold very well. You can see exposed copper wire where the magnetic pulse forced the wire to expand out of its sheathing.
	The new 8AWG coil. We experimented with other metal objects. This soda can probably traveled over 50 feet high.
	We wondered if our great results were from the very light weight of the disk so we weighed it down with a 1' section of 2"x4". The disk immediately wrapped around the wood and launched nearly as high as the disk did alone (est 50'-100'). 5kV charge (1500J).
	Note: We never performed a full power (6kJ) test. The highest we tried was 7,000V and 2,940kJ of energy. We were going to experiment with more power, but when we tried to charge the cap up higher, we had a flash over on a diode in our rectifier which left us limping with just a 1-diode half wave instead of a 4-diode full wave. When I rebuild I will build the rectifier over spec and submerge the diodes under mineral oil.
	The schematic is the same as our cancrusher schematic, except instead of crushing a soda can it launches disks of course.

Technical specifications:

Power supply:
-Neon Sign Transformer, 120VAC / 12,000VAC, 120mA
-Variac, 120VAC in, 0-140VAC out, 8A
-four diodes, each 7kV  0.2A
-multi-tap 1M high-power resistor

Switch:
-simple spark gap, 2 bolts mounted on lexan supports
-homemade discharge rod, 3/8" steel

Capacitors:
-Maxwell Pulse cap, 10kV 120uF

Launching coil:
-#8 AWG standard THHN copper wire wound in a flat spiral of about 10 turns (best coil, many others were tried)

Projectile:
-various copper rings
-ring made out of 1/4" copper tubing
-old hard drive platters (5" aluminum disks)
-aluminum soda can
- 2 x 4's !!!
 

This launcher was built during the summer of 98. The very first test took place in the first week of July, myself (Tristan Stewart) and Heinz Wahl participating. The first few launchers were made with heavy copper rings, and only at a few thousand volts. The rings would launch maybe 20 - 30 feet in the air.

    Well, here's how the story goes.  I was launching some copper rings (7-9-98) and I wanted to see how this hard drive disk would work. I didn't expect it to work very good because it was much heavier than the rings we were using and it also has much more air resistance because of its large flat surface area.  So I thought I'd give it a low power test first.  Unfortunately it began to rain so I had to move everything into the garage.  The spark gap was set to fire at 5kV.  The capacitor began to charge.  It kept charging, and charging... seemed like it should have fired by now.  All the sudden the spark gap started arcing across the wooden support pieces so we shut the power off.  I grabbed my good old discharge rod and quickly shorted the spark gap terminals.  BANG! Now that was a big bang, big enough to create a small shockwave in the air that I felt, and bounce the launching assembly a bit.  So we looked around for the disk...but it was gone?!? After searching the whole garage I noticed that it had traveled strait up and was embedded in the roof!  

 We figure that because the spark gaps were used so much that the char that had built up on the contact points held the voltage off a little higher than it should off.  From now on I'll make sure that the contacts are clean!  Assuming that the capacitor didn't charge above its V rating, I calculated that the maximum amount of energy delivered from the capacitor would at most be around 6kJ (6000 Joules).  As soon as the weather permits, I hope to do some more hard drive launches - but this time they will be outdoors!
 

We ran more experiments a few weeks later. A couple different launching coils were used with almost no differing results.  For the first tests I made a ring from bending a piece of copper tubing into a loop and then soldering it together.  This would not hold up! At only around 5kV charge the ring was thrown into the air and ripped apart at the solder joint! The first launcher was about 15 turns of #12 wire. The second launcher was about 7 turns of #8 wire. The only difference was that the #12 was too flimsy and was eventually destroyed under the force of the launch.

Highest Launch: Approximately 125'
Setup: #12 coil, cap charged to 7kV, hard drive disk

An 8kV launch was made, but the disk & the launching coil were so distorted that the disk spun violently and launched out into a field.  The launching coil was bent so far out of shape it was scrapped. Unfortunately, no other high power tests were made because a diode was destroyed. But we could still charge up to a few thousand volts, so the experimenting continued...

EMP-1A

Our first ring launcher

 ID Code: EMP-1A-LIPG-400

Current status: Completed & decommissioned

I would like to point out here that we did not know very much about magnetic launchers at the time. About all the info we had to go on was to charge a big HV cap up and discharge it through a spark gap into a coil that had a ring sitting on it. We were doing pretty good to get successful launches and not kill ourselves in the process LOL!

  I have had great success launching various conductive things into the atmosphere! It all started in the summer of 1997 when I obtained two Cornell-Dubiler high voltage capacitors. I believe they are PFC capacitors for distribution lines (but I am not sure).

The only pic I have is of the caps we used.

Technical specifications:

Power supply:
-Neon Sign Transformer, 120VAC / 7000VAC, 60mA
-Variac, 120VAC in, 0-140VAC out, 8A
-10kV bridge rectifier,  0.1A
-multi-tap 1M high-power resistor

Switch:
-simple spark gap, 2 bolts mounted on lexan supports
-homemade discharge rod, 3/8" steel

Capacitors:
-two  caps (10kV 4uF each) in parallel or series

Launching coil:
-#8 AWG standard THHN copper wire wound around 4" PVC, in a close-wound solenoid of approximately 40 turns

Projectile:
-Copper ring (gasket), very thin

With the above setup and near full charge, we could launch the copper ring approximately 25-50 feet straight up.

This was our first successful magnetic launcher!  We were very thrilled with the results.  The ring would launch faster than the eye could see.  The bang of the spark gap was very loud!

This webpage originally born on 2-22-99. Last updated on 8-21-06