5KJ 4 stage rail gun (complete)
ea6b607, Fri May 16 2008, 12:35AMI don't have time right now to go into too thorough an explanation, but I thought I'd start a thread so I stop hijacking Zephir (sp?)
Anyways it uses 4 sets of 4 525Volt 2400uF Capacitors in parallel with a 1/2" lexan bore charged by a MOT and injected using a Dema 1500 Psi solenoid trigger for a 12oz paintball CO2 canister charged to 1200psi. Velocity was measured using two microphones on by the muzzle second by a 1/8" piece of wood and measuring time between hits on a distance of 20 feet. Final velocity of 620m/s at full charge (5.3Kj along with 636 joules imparted by injector). projectile was a 1/2"x1/2"x1/2" piece of aluminum weighing 8 grams. barrel length is 48 inches with 4 8inch long sets of independent rails (copper 3/4" x 1/8") inner barrel thats not covered by rails is 1/8" derilen thermal plastic. Supported by 1 1/2"x1/4" steel grade 8 bolts every 2 1/2" of the barrel. Final charger is powered by 2 9ah lead acid battery's though an inverter followed by the MOT.
Here's my website in early development (all the pictures are old, but it has my original designs)
I think the thing that helped the most with my efficiency was the independent multiple sets of rails which reduced peak current without having to add an inductor and still preserving total power.
Future development on second generation employing round bore and automatic feeding. Along with improved portable charger already started.
Large view
Zoomed view
EDIT: Updated images
Re: 5KJ 4 stage rail gun (complete)
Quantum Singularity, Fri May 16 2008, 01:05AM
Thats a good looking setup! Nicely done! Looking forward to some more info and pics (video would be great too
).
Quantum Singularity, Fri May 16 2008, 01:05AM
Thats a good looking setup! Nicely done! Looking forward to some more info and pics (video would be great too
).Re: 5KJ 4 stage rail gun (complete)
Firefox, Fri May 16 2008, 01:15AM
That is an absolutely incredible design. If you don't mind me asking, how did you machine all the fine parts for that thing (and how much did all that cost)? Also, It is a pretty ingenious idea to stage a railgun. Also, I am very impressed with the efficiency of this setup. At 620 m/s you're putting over 1.5kJ of energy behind that cube, and with the injector energy taken away, its still at an impressive 901 J from EM forces. I mean, thats 17% efficiency! I think you may be onto something. Do you think you could give some bigger close up pictures of this thing, as well as some damage dealt by it?
Note: Before the Mods get here, the max picture width is 400 pixels. Thumbnail those shots!
Firefox, Fri May 16 2008, 01:15AM
That is an absolutely incredible design. If you don't mind me asking, how did you machine all the fine parts for that thing (and how much did all that cost)? Also, It is a pretty ingenious idea to stage a railgun. Also, I am very impressed with the efficiency of this setup. At 620 m/s you're putting over 1.5kJ of energy behind that cube, and with the injector energy taken away, its still at an impressive 901 J from EM forces. I mean, thats 17% efficiency! I think you may be onto something. Do you think you could give some bigger close up pictures of this thing, as well as some damage dealt by it?
Note: Before the Mods get here, the max picture width is 400 pixels. Thumbnail those shots!
Re: 5KJ 4 stage rail gun (complete)
ea6b607, Fri May 16 2008, 01:58AM
First, how do you thumbnail pictures I only know hot to do it in html.
I really have no fancy tools pretty much all I used was a table saw a drill press and a miter saw (along with a friend of mine who has a metal chop saw for the copper and aluminum). A lot of time and a lot of measuring. The actual rail gun is currently at my school (apparently they worry about people bringing in swiss army knifes, but railguns are fine) A different friend of mine took some pictures (he has a professional photography business and got some nice action shots of the muzzle while firing) when I fired it, but I still need to get them from him. The video is I got was kind of crappy since the person didn't realize there was a zoom, but I'll upload it later anyways. I Still have the 1/8" piece of wood that it made a perfect square hole in with barely any splintering (sign of high speed as little energy was transferred to the wood. After it traveled through the wood it went who knows how far into the side of the hill I shot it at. Since these pictures I have completely rewired my capacitor bank and remade my charging box (or am in the process of doing that), I'm going to start the V2 pretty soon. Cost wise the whole thing cost me about $500, but I got a $400 grant from the HAL department at my school for the project.
Edit: thanks to whatever mod fixed my pics!
ea6b607, Fri May 16 2008, 01:58AM
First, how do you thumbnail pictures I only know hot to do it in html.
I really have no fancy tools pretty much all I used was a table saw a drill press and a miter saw (along with a friend of mine who has a metal chop saw for the copper and aluminum). A lot of time and a lot of measuring. The actual rail gun is currently at my school (apparently they worry about people bringing in swiss army knifes, but railguns are fine) A different friend of mine took some pictures (he has a professional photography business and got some nice action shots of the muzzle while firing) when I fired it, but I still need to get them from him. The video is I got was kind of crappy since the person didn't realize there was a zoom, but I'll upload it later anyways. I Still have the 1/8" piece of wood that it made a perfect square hole in with barely any splintering (sign of high speed as little energy was transferred to the wood. After it traveled through the wood it went who knows how far into the side of the hill I shot it at. Since these pictures I have completely rewired my capacitor bank and remade my charging box (or am in the process of doing that), I'm going to start the V2 pretty soon. Cost wise the whole thing cost me about $500, but I got a $400 grant from the HAL department at my school for the project.
Edit: thanks to whatever mod fixed my pics!
Re: 5KJ 4 stage rail gun (complete)
Spedy, Fri May 16 2008, 04:00AM
=D Wow that's awesome. So, the school gave you $400 just for building the thing? That's cool too.
17% efficiency? I'm no expert on railguns, but isn;t that unusually high? Anywho, good job man! thats COOL.
Spedy, Fri May 16 2008, 04:00AM
=D Wow that's awesome. So, the school gave you $400 just for building the thing? That's cool too.
17% efficiency? I'm no expert on railguns, but isn;t that unusually high? Anywho, good job man! thats COOL.
Re: 5KJ 4 stage rail gun (complete)
ea6b607, Fri May 16 2008, 04:37AM
17% is fairly decent for a small scale one, but for instance the 9MJ rail gun made by BAE systems achieved 47% efficiency with an expected 66%,
ea6b607, Fri May 16 2008, 04:37AM
17% is fairly decent for a small scale one, but for instance the 9MJ rail gun made by BAE systems achieved 47% efficiency with an expected 66%,
Re: 5KJ 4 stage rail gun (complete)
zephir, Fri May 16 2008, 08:22AM
wow, thats just amazing. Good job on coming up with the idea of a multi-stage rail gun. I haven't seen that before.
I had a similar idea, but with a 2 stage rail gun instead. How are your rails wired? Do you have four separate sets of capacitors, one for each rail?
And for your rail gun test shots, you should consider a proper backstop if you don't already have one. Your projectile speed is just 90 m/s less of my rifle (710m/s, 8 gram projectile), which I know for a fact would horribly maim someone if I accidentally shot someone with it. You should have a proper backstop behind your wood target, to catch any rounds before you accidentally shoot someone. A large mound of sand or at least a sandbag wall would be sufficient.
and shouldn't this be in the projects section of the forum?
zephir, Fri May 16 2008, 08:22AM
wow, thats just amazing. Good job on coming up with the idea of a multi-stage rail gun. I haven't seen that before.
I had a similar idea, but with a 2 stage rail gun instead. How are your rails wired? Do you have four separate sets of capacitors, one for each rail?
And for your rail gun test shots, you should consider a proper backstop if you don't already have one. Your projectile speed is just 90 m/s less of my rifle (710m/s, 8 gram projectile), which I know for a fact would horribly maim someone if I accidentally shot someone with it. You should have a proper backstop behind your wood target, to catch any rounds before you accidentally shoot someone. A large mound of sand or at least a sandbag wall would be sufficient.
and shouldn't this be in the projects section of the forum?
Re: 5KJ 4 stage rail gun (complete)
ea6b607, Fri May 16 2008, 12:14PM
The rails are physically separated in the gun. Each one of those 4awg red wires leads to a 8" copper set and the large black wire is a common ground. The piece of wood by no meens was meant to catch eh bullet it was only used to create a sound spike when the projectile hit it so I could measure the time between the muzzle and the piece of wood. there is a large flood control hill behind it which actually stops the round. Each stage uses 4 of those capacitors which after the charging circuit is unplugged are electrictly isolated.
ea6b607, Fri May 16 2008, 12:14PM
zephir wrote ...
wow, thats just amazing. Good job on coming up with the idea of a multi-stage rail gun. I haven't seen that before.
I had a similar idea, but with a 2 stage rail gun instead. How are your rails wired? Do you have four separate sets of capacitors, one for each rail?
And for your rail gun test shots, you should consider a proper backstop if you don't already have one. Your projectile speed is just 90 m/s less of my rifle (710m/s, 8 gram projectile), which I know for a fact would horribly maim someone if I accidentally shot someone with it. You should have a proper backstop behind your wood target, to catch any rounds before you accidentally shoot someone. A large mound of sand or at least a sandbag wall would be sufficient.
and shouldn't this be in the projects section of the forum?
wow, thats just amazing. Good job on coming up with the idea of a multi-stage rail gun. I haven't seen that before.
I had a similar idea, but with a 2 stage rail gun instead. How are your rails wired? Do you have four separate sets of capacitors, one for each rail?
And for your rail gun test shots, you should consider a proper backstop if you don't already have one. Your projectile speed is just 90 m/s less of my rifle (710m/s, 8 gram projectile), which I know for a fact would horribly maim someone if I accidentally shot someone with it. You should have a proper backstop behind your wood target, to catch any rounds before you accidentally shoot someone. A large mound of sand or at least a sandbag wall would be sufficient.
and shouldn't this be in the projects section of the forum?
The rails are physically separated in the gun. Each one of those 4awg red wires leads to a 8" copper set and the large black wire is a common ground. The piece of wood by no meens was meant to catch eh bullet it was only used to create a sound spike when the projectile hit it so I could measure the time between the muzzle and the piece of wood. there is a large flood control hill behind it which actually stops the round. Each stage uses 4 of those capacitors which after the charging circuit is unplugged are electrictly isolated.
Re: 5KJ 4 stage rail gun (complete)
zephir, Sat May 17 2008, 06:02AM
ohh i see. thanks of explaining.
zephir, Sat May 17 2008, 06:02AM
ohh i see. thanks of explaining.
Re: 5KJ 4 stage rail gun (complete)
ea6b607, Sun May 18 2008, 07:42PM
Someone wanted to see the mechanism I used for connecting the wires to the rails
Large view
Zoomed view
ea6b607, Sun May 18 2008, 07:42PM
Someone wanted to see the mechanism I used for connecting the wires to the rails
Large view
Zoomed view
Re: 5KJ 4 stage rail gun (complete)
rp181, Sun May 18 2008, 08:00PM
thanks =) where are the rails? are they on the top and bottom? how does the piece of copper sticking out stay connected to the rails without getting in the way of the projectile?
man thats a good camera, i thought it was rendered =)
rp181, Sun May 18 2008, 08:00PM
thanks =) where are the rails? are they on the top and bottom? how does the piece of copper sticking out stay connected to the rails without getting in the way of the projectile?
man thats a good camera, i thought it was rendered =)
Re: 5KJ 4 stage rail gun (complete)
ea6b607, Sun May 18 2008, 08:27PM
That's a early picture, the rails weren't on it at that time. The rails themselves are on the top and bottom secured with two part epoxy the little metal tabs where secured with a butane torch and a lot of solder later on (I think your probably won't be able to use a torch on polyethylene on PVC as it melts way to fast). The tabs where connected to the side of the rails so it was impossible for them to touch the projectile. And ya I have a Olympus E-500 and love it. Also PVC will shatter as well so be careful with that. There is a lot of force pushing those apart and even using thick polycarbonate like I did on mine can still be torn apart with an unexpectedly low amount of force.
ea6b607, Sun May 18 2008, 08:27PM
That's a early picture, the rails weren't on it at that time. The rails themselves are on the top and bottom secured with two part epoxy the little metal tabs where secured with a butane torch and a lot of solder later on (I think your probably won't be able to use a torch on polyethylene on PVC as it melts way to fast). The tabs where connected to the side of the rails so it was impossible for them to touch the projectile. And ya I have a Olympus E-500 and love it. Also PVC will shatter as well so be careful with that. There is a lot of force pushing those apart and even using thick polycarbonate like I did on mine can still be torn apart with an unexpectedly low amount of force.
Re: 5KJ 4 stage rail gun (complete)
rp181, Sun May 18 2008, 09:13PM
Heres what i was going to do: clamp all the parts together and drill a hole in the center. With the table saw, dado it so the rails slide in (and filler plastic). Before sliding it, the rod would be soldered with a propane torch, away from plastic. Once its put in, and plastic bolted down, then the rod would be sandwiched between the plastic, with some sticking out. Then ide sand te rod flat, so i could put bolts in it.
rp181, Sun May 18 2008, 09:13PM
Heres what i was going to do: clamp all the parts together and drill a hole in the center. With the table saw, dado it so the rails slide in (and filler plastic). Before sliding it, the rod would be soldered with a propane torch, away from plastic. Once its put in, and plastic bolted down, then the rod would be sandwiched between the plastic, with some sticking out. Then ide sand te rod flat, so i could put bolts in it.
Re: 5KJ 4 stage rail gun (complete)
badastronaut, Sun May 18 2008, 10:29PM
Wow!!! That is an awesome setup!
You're injector alone is an impressive accomplishment. 400 m/s is no laughing matter.
Can we see some pictures of that wooden plate? I like how you used sound to measure speed. I have had problems measuring speed with my own setup. Can you make a diagram of where the railgun, microphone, and wooden plate. Equations would be nice too :D
Very cool indeed!
badastronaut, Sun May 18 2008, 10:29PM
Wow!!! That is an awesome setup!
You're injector alone is an impressive accomplishment. 400 m/s is no laughing matter.
Can we see some pictures of that wooden plate? I like how you used sound to measure speed. I have had problems measuring speed with my own setup. Can you make a diagram of where the railgun, microphone, and wooden plate. Equations would be nice too :D
Very cool indeed!
Re: 5KJ 4 stage rail gun (complete)
ea6b607, Mon May 19 2008, 02:28AM
Sounds like a good idea rp, but you might need to weld the metal
not much of a significant target, but was never meant to be. Still made a neat square hole.
I made this diagram to help to explain the measurement method I used. This will calculate the speed and you can find the distance between muzzle and target and thus can fine speed r=dt.
I used Adobe Soundbooth to measure the time, but you can probably find a free software as long as it shows time and dB
Here's a mockup of my new charging box (I'm going to use Lexan for the final version) weighs 35lbs and has 18ah of battery with 700Watts of 2KVAC/DC or 700watts 110VAC or a combination of the two. Also supplies 24VAC for my solenoid.
Also, I have a question, I have 4 350amp 2KV SCR I got for crazy cheap and was wondering what would be the estimated amount of power I could pump through them before they blow.
ea6b607, Mon May 19 2008, 02:28AM
Sounds like a good idea rp, but you might need to weld the metal
not much of a significant target, but was never meant to be. Still made a neat square hole.
I made this diagram to help to explain the measurement method I used. This will calculate the speed and you can find the distance between muzzle and target and thus can fine speed r=dt.
I used Adobe Soundbooth to measure the time, but you can probably find a free software as long as it shows time and dB
Here's a mockup of my new charging box (I'm going to use Lexan for the final version) weighs 35lbs and has 18ah of battery with 700Watts of 2KVAC/DC or 700watts 110VAC or a combination of the two. Also supplies 24VAC for my solenoid.
Also, I have a question, I have 4 350amp 2KV SCR I got for crazy cheap and was wondering what would be the estimated amount of power I could pump through them before they blow.
Re: 5KJ 4 stage rail gun (complete)
Backyard Skunkworks, Mon May 19 2008, 03:00AM
Audacity could work for the sound file analysis, best free audio editor out there.
Generally SCRs can take about 8-10 times their rated current for a surge, so they might stand 3.5kA. To be safe I'd keep in somewhere in the 2.#kA range, just parallel them for higher amps (as long as the circuit is somewhat inductive they should all close in time).
Backyard Skunkworks, Mon May 19 2008, 03:00AM
Audacity could work for the sound file analysis, best free audio editor out there.
Generally SCRs can take about 8-10 times their rated current for a surge, so they might stand 3.5kA. To be safe I'd keep in somewhere in the 2.#kA range, just parallel them for higher amps (as long as the circuit is somewhat inductive they should all close in time).
Re: 5KJ 4 stage rail gun (complete)
badastronaut, Mon May 19 2008, 03:01AM
Regarding the SCR's, the answer is not enough to handle your 5kJ cap bank. For pulsed applications, each SCR would be able to handle 3500 amps for under 10ms.
Can you annotate that diagram with actual data? What kind of uncertainty do you have with this method of measurement? How about posting the sound file? :)
What do the rails look like after firing?
badastronaut, Mon May 19 2008, 03:01AM
Regarding the SCR's, the answer is not enough to handle your 5kJ cap bank. For pulsed applications, each SCR would be able to handle 3500 amps for under 10ms.
Can you annotate that diagram with actual data? What kind of uncertainty do you have with this method of measurement? How about posting the sound file? :)
What do the rails look like after firing?
Re: 5KJ 4 stage rail gun (complete)
rp181, Mon May 19 2008, 03:04AM
O.o where did you get those SCR's? i got a 1200v 200A 5500A surge SCR thats 110$, i had it donated though.
rp181, Mon May 19 2008, 03:04AM
O.o where did you get those SCR's? i got a 1200v 200A 5500A surge SCR thats 110$, i had it donated though.
Re: 5KJ 4 stage rail gun (complete)
Electroholic, Mon May 19 2008, 03:37AM
5kJ is actually Muzzle energy, so yea the SCRs will only work once if you put them in the rail gun.
they would work for a mid size coil gun tho.
Electroholic, Mon May 19 2008, 03:37AM
badastronaut wrote ...
Regarding the SCR's, the answer is not enough to handle your 5kJ cap bank. For pulsed applications, each SCR would be able to handle 3500 amps for under 10ms.
Can you annotate that diagram with actual data? What kind of uncertainty do you have with this method of measurement? How about posting the sound file? :)
What do the rails look like after firing?
Regarding the SCR's, the answer is not enough to handle your 5kJ cap bank. For pulsed applications, each SCR would be able to handle 3500 amps for under 10ms.
Can you annotate that diagram with actual data? What kind of uncertainty do you have with this method of measurement? How about posting the sound file? :)
What do the rails look like after firing?
5kJ is actually Muzzle energy, so yea the SCRs will only work once if you put them in the rail gun.
they would work for a mid size coil gun tho.
Re: 5KJ 4 stage rail gun (complete)
badastronaut, Tue May 20 2008, 03:42AM
I was looking at your speed measurement diagram, and it looks like that one is the case when the projectile is traveling slower than the speed of sound. I think they should look like these.
The speed of sound is about 343 m/s, and your projectile travels almost twice that.
badastronaut, Tue May 20 2008, 03:42AM
I was looking at your speed measurement diagram, and it looks like that one is the case when the projectile is traveling slower than the speed of sound. I think they should look like these.
The speed of sound is about 343 m/s, and your projectile travels almost twice that.
Re: 5KJ 4 stage rail gun (complete)
ea6b607, Tue May 20 2008, 04:20AM
Ya your right, I did that backwards on mine. Anyways I just used the first sound peak from each channel. I had my recording set at 96000hertz so accuracy for measurement is .00001 seconds (make sure to use beginning of peak) at 20 feet~6.096meters my measure time was .0096seconds so 6.096/.00989seconds~ 616.38m/s +or - 0.6m/s due to accuracy limitation. Measurement accuracy will get significantly worse at closer distances or with lower recording frequencies. I originally thought of using optical sensors, but I figured the muzzle flash would mess that up,
ea6b607, Tue May 20 2008, 04:20AM
Ya your right, I did that backwards on mine. Anyways I just used the first sound peak from each channel. I had my recording set at 96000hertz so accuracy for measurement is .00001 seconds (make sure to use beginning of peak) at 20 feet~6.096meters my measure time was .0096seconds so 6.096/.00989seconds~ 616.38m/s +or - 0.6m/s due to accuracy limitation. Measurement accuracy will get significantly worse at closer distances or with lower recording frequencies. I originally thought of using optical sensors, but I figured the muzzle flash would mess that up,
Re: 5KJ 4 stage rail gun (complete)
badastronaut, Tue May 20 2008, 04:30AM
What is the time between the launch peak in the left channel and the launch peak in the right channel?
badastronaut, Tue May 20 2008, 04:30AM
What is the time between the launch peak in the left channel and the launch peak in the right channel?
Re: 5KJ 4 stage rail gun (complete)
ea6b607, Wed May 21 2008, 02:58AM
0.01783seconds. By the way when I say peak I'm not actually talking about the highest point but when the sound begins to peak.
ea6b607, Wed May 21 2008, 02:58AM
0.01783seconds. By the way when I say peak I'm not actually talking about the highest point but when the sound begins to peak.
Re: 5KJ 4 stage rail gun (complete)
Gunner, Fri Jun 13 2008, 09:56PM
Cool...could you take some damage pics?:P
Gunner, Fri Jun 13 2008, 09:56PM
Cool...could you take some damage pics?:P
Print this page