If you need assistance, please send an email to forum at 4hv dot org. To ensure your email is not marked as spam, please include the phrase "4hv help" in the subject line. You can also find assistance via IRC, at irc.shadowworld.net, room #hvcomm.
Support 4hv.org!
Donate:
4hv.org is hosted on a dedicated server. Unfortunately, this server costs and we rely on the help of site members to keep 4hv.org running. Please consider donating. We will place your name on the thanks list and you'll be helping to keep 4hv.org alive and free for everyone. Members whose names appear in red bold have donated recently. Green bold denotes those who have recently donated to keep the server carbon neutral.
Special Thanks To:
Aaron Holmes
Aaron Wheeler
Adam Horden
Alan Scrimgeour
Andre
Andrew Haynes
Anonymous000
asabase
Austin Weil
barney
Barry
Bert Hickman
Bill Kukowski
Blitzorn
Brandon Paradelas
Bruce Bowling
BubeeMike
Byong Park
Cesiumsponge
Chris F.
Chris Hooper
Corey Worthington
Derek Woodroffe
Dalus
Dan Strother
Daniel Davis
Daniel Uhrenholt
datasheetarchive
Dave Billington
Dave Marshall
David F.
Dennis Rogers
drelectrix
Dr. John Gudenas
Dr. Spark
E.TexasTesla
eastvoltresearch
Eirik Taylor
Erik Dyakov
Erlend^SE
Finn Hammer
Firebug24k
GalliumMan
Gary Peterson
George Slade
GhostNull
Gordon Mcknight
Graham Armitage
Grant
GreySoul
Henry H
IamSmooth
In memory of Leo Powning
Jacob Cash
James Howells
James Pawson
Jeff Greenfield
Jeff Thomas
Jesse Frost
Jim Mitchell
jlr134
Joe Mastroianni
John Forcina
John Oberg
John Willcutt
Jon Newcomb
klugesmith
Leslie Wright
Lutz Hoffman
Mads Barnkob
Martin King
Mats Karlsson
Matt Gibson
Matthew Guidry
mbd
Michael D'Angelo
Mikkel
mileswaldron
mister_rf
Neil Foster
Nick de Smith
Nick Soroka
nicklenorp
Nik
Norman Stanley
Patrick Coleman
Paul Brodie
Paul Jordan
Paul Montgomery
Ped
Peter Krogen
Peter Terren
PhilGood
Richard Feldman
Robert Bush
Royce Bailey
Scott Fusare
Scott Newman
smiffy
Stella
Steven Busic
Steve Conner
Steve Jones
Steve Ward
Sulaiman
Thomas Coyle
Thomas A. Wallace
Thomas W
Timo
Torch
Ulf Jonsson
vasil
Vaxian
vladi mazzilli
wastehl
Weston
William Kim
William N.
William Stehl
Wesley Venis
The aforementioned have contributed financially to the continuing triumph of 4hv.org. They are deserving of my most heartfelt thanks.
Registered Member #2169
Joined: Tue Jun 09 2009, 10:49PM
Location:
Posts: 3
Hi all, I'm new, I have done a lot of research on electric weapons and decided that the most potential on a personal scale would have to go to electrothermal guns/accelerators. I have decided to build one myself using roughly 300-500J in a portable capacitor bank. The barrel will be about a 1.5 foot steel pipe with a very small perhaps 8mm projectile diameter. What i'm unsure about is the way to start the arc to heat the air. On one hand you have rp181 with his experiments using different matierials to start it which seem extremely powerful and promising somewhat like "metafex". On the other hand you have Lomy not using any fuel to start the arc and having a very powerful weapon just using a trigatron. Im not sure whether its simply that its easier to ignite the arc with the fuel (aluminum powder, water steel powder etc) or to use a trigatron. my goal is to get a projectile to roughly 50% efficiency. What is the best way to do this? thank you all in advance and please excuse my rough language and possibly inaccurate terminology.
Registered Member #1062
Joined: Tue Oct 16 2007, 02:01AM
Location:
Posts: 1529
50% will be very difficult for that low energy. The most power is usually obtained with solid, non-explosive fuels. The one you saw of mine was very difficult, that was a spur of the moment thing. Lomy went much farther into it, but the trigatron method is still worse in my opinion. If you plan on trying that method, Use a non-metallic barrel to limit thermal losses. With the standard fuel way, use powder already contacted, and switch the power on externally. Amounts you use should be tested, to get the best results. Some links to people that have done this more seriously: This one is sheer power, it uses the powder in the electrodes, and switches the power into it: DYI is more after a electrothermalchemical gun, a ETG, but you use explosive, organic compounds. What people have found is that the main cause of poor preformance is the excess chamber space. The chamber should be just big enough for the fuel, so usuially the lower part of the barrel suffice's, unless high powers are used. You are going to have difficulty getting high efecinacy with only 500 joules. ETG's are like railguns in the fact more power means more efeciancy, depending on the quality of the build. When you try a shot, check the leftover bank voltage. If it is high (more than a fifth of the starting voltage or so), reconfigure the bank for a higher voltage, maybe around a kilovolt.
EDIT: For future refrence, ETG's are not electromagnetic projectile accelerators, but they are usually posted in that section.
Registered Member #2040
Joined: Fri Mar 20 2009, 10:13PM
Location: Fairfax VA
Posts: 180
If you are using electrolytic capacitors then don't forget to take into account dielectric absorption when you check the capacitor bank after a shot. You must check the voltage quickly or your data will be skewed. If you do a search on the forum for dielectric soak you can find out more about it.
Registered Member #543
Joined: Tue Feb 20 2007, 04:26PM
Location: UK
Posts: 4992
nattayb wrote ...
Hi all, I'm new, I have done a lot of research on electric weapons and decided that the most potential on a personal scale would have to go to electrothermal guns/accelerators. I have decided to build one myself using roughly 300-500J in a portable capacitor bank. The barrel will be about a 1.5 foot steel pipe with a very small perhaps 8mm projectile diameter. What i'm unsure about is the way to start the arc to heat the air. On one hand you have rp181 with his experiments using different matierials to start it which seem extremely powerful and promising somewhat like "metafex". On the other hand you have Lomy not using any fuel to start the arc and having a very powerful weapon just using a trigatron. Im not sure whether its simply that its easier to ignite the arc with the fuel (aluminum powder, water steel powder etc) or to use a trigatron. my goal is to get a projectile to roughly 50% efficiency. What is the best way to do this? thank you all in advance and please excuse my rough language and possibly inaccurate terminology.
Take care what you do, because it seems to me that the barreled "weapon" you describe here - with a barrel of less than 2' long and a propellant - could well constitute a "firearm" in UK and EU law, and probably in other jurisdictions too. It is your sole responsibility to ensure that you do not infringe firearms or explosives legislation in your own jurisdiction. - Harry Moderator
Registered Member #1062
Joined: Tue Oct 16 2007, 02:01AM
Location:
Posts: 1529
Does that mean a trigatron method would not constitute a firearm? If your in the US, it is legal to make weapons, as long as you follow some other laws (they do not pertain to ETG's), or transport/sell them.
Registered Member #543
Joined: Tue Feb 20 2007, 04:26PM
Location: UK
Posts: 4992
rp181 wrote ...
Does that mean a trigatron method would not constitute a firearm? If your in the US, it is legal to make weapons, as long as you follow some other laws (they do not pertain to ETG's), or transport/sell them.
It is the responsibility of each individual member to ensure that they do not break the law in their own country. 4HV.org cannot give an opinion, nor take responsibility, for the lawfulness of any conduct by forum users, throughout the world.
Registered Member #2169
Joined: Tue Jun 09 2009, 10:49PM
Location:
Posts: 3
I'm in the US, and Im well aware of firearms laws. I think the solid propellant that rp181 uses is probably my best bet. I have also considered discharging the capacitors in parallel thus having a much smaller time constant so more energy is put into the propellant much faster with a higher current. I could increase the energy depending on the size of the caps so that it is still handheld. does anyone know any of the physics formulas for this kind of discharge into aluminum or so? I'm not sure whether the efficiency is high because of the energy in the caps or if aluminum releasing energy has somethign to do with it?
Registered Member #1062
Joined: Tue Oct 16 2007, 02:01AM
Location:
Posts: 1529
There is no equation, and if there was, it would be complicated there are tons of variables. Putting the capacitors in series would give a lower pulse time, parallel would make a longer pulse.
Registered Member #2169
Joined: Tue Jun 09 2009, 10:49PM
Location:
Posts: 3
When you all say keep the chamber small you mean the diameter of the barrel? or the length also? because my idea would be to use a foot to two feet in length with a small bore I think i could use 3 large caps together with about 800J which should be enough. I will use a metal nail that fits it best probably use several different amounts and types of solid propellants.
This site is powered by e107, which is released under the GNU GPL License. All work on this site, except where otherwise noted, is licensed under a Creative Commons Attribution-ShareAlike 2.5 License. By submitting any information to this site, you agree that anything submitted will be so licensed. Please read our Disclaimer and Policies page for information on your rights and responsibilities regarding this site.
Need help with electrogun!
