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Plasma Cannon?

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guitardude012

Thu Dec 18 2008, 04:37AM

Registered Member #968 Joined: Fri Aug 24 2007, 04:54PM
Location: Norman, Oklahoma
Posts: 104

Even at 50% efficiency it will be less than the M99 at 16500 J... Still much more recoil than 12ga shotgun slugs though =/

cduma

Fri Dec 19 2008, 05:20PM

Registered Member #1822 Joined: Fri Nov 21 2008, 08:04PM
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Posts: 300

Wow! Thanks for all of the replys!

In order for a rail gun to work the projectile needs to be moving rapidly before it reaches the rails or it just becomes a spot welder correct?

Will the plasma cannon work with aluminum foil?

rp181

Fri Dec 19 2008, 09:59PM

Registered Member #1062 Joined: Tue Oct 16 2007, 02:01AM
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No it is not required for the projectile to be moving. hobbyists usually do that, because it eliminates the switch. The navy railgun uses a solid state switch. Take a look at this thread:

Plasma will work with aluminum foil. It would take some experimenting to find a good amount.

Hon1nbo

Fri Dec 19 2008, 11:19PM

Registered Member #902 Joined: Sun Jul 15 2007, 08:17PM
Location: North Texas
Posts: 1040

guitardude012 wrote ...

That ETG is amazing. I think what DaJJHman meant by "not that impressive" is that it is being compared to launching potatoes for hundreds of yards or through cinder blocks using only some pvc pipe, hair spray , and a grill lighter.

yeah I meant compared with a traditional spud gun... ETGs are pretty cool, and I plan to build one at some point.

aonomus

Sat Dec 20 2008, 01:02AM

Registered Member #1497 Joined: Thu May 22 2008, 05:24AM
Location: Toronto, Ontario, Canada
Posts: 801

Don't pull another Sam Barros and intentionally hit TATP to test if it is sensitive.

You might be best to try baby steps, you might get too much pressure from Alu for whatever you use to build it....

DYI

Fri Jan 09 2009, 03:24AM

Registered Member #1917 Joined: Fri Jan 09 2009, 02:38AM
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Posts: 62

I was that guy testing acetone peroxide as an ETC propellant, although that testing has been cut short at the moment. This isn't the right board to post the results of those tests, but suffice it to say that, for simple hobbyist gun designs, TCAP is a VERY impressive propellant (if somewhat unforgiving of errors).

I'm now working on the electrothermal component of the design. I'll first be testing different propellants (including air and water) and switching systems, and determining how much of an advantage a fast pulse, high voltage system has over a basic electrolytic bank of the same energy for a few different, simple ETG designs, and then constructing a much larger system based on the results of that testing. Unless there's some unwritten forum code preventing me from doing so, I'll start a thread on that after I get my setup fully assembled.

Potato cannons and electrothermal guns are not easily or usefully meshed technologies - potato guns require low pressure and gradual acceleration. Electric arcs are good at heating low volumes to ridiculous temperatures extremely quickly, the exact oposite of what is required for vegetable acceleration. If you have a 45uF 35kV bank, you can accomplish much more interesting results than almost anything loosely describe-able as a potato gun (except maybe Larda's HyGaC20).

rp181

Fri Jan 09 2009, 04:30AM

Registered Member #1062 Joined: Tue Oct 16 2007, 02:01AM
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If using this for a railgun, I think it would be much more viable to use a pulse transformer to step the voltage down, Railguns do not need 35kV that would just make rail erosion a huge problem.
High voltage is great for a ETG. In a couple paper's i was reading, its better to have the majority of the current to pass through plasma, increasing its density.

Backyard Skunkworks

Sat Jan 10 2009, 07:29AM

Registered Member #1262 Joined: Fri Jan 25 2008, 05:22AM
Location: Maryland, USA
Posts: 451

I can imagine that TATP would yield good results, but other compounds would be both far safer and somewhat more powerful. The advantage to TATP is the ease of synthesis, but the extreme instability is something you just cant get around. Stoichiometric oxyhydrogen gas or nitrocellulose are probably better bets safety and power wise, but IMO the entire idea of an ETC is basically cheating. I mean really, its more like a spud gun than a real ETG.

rp181

Sat Jan 10 2009, 04:39PM

Registered Member #1062 Joined: Tue Oct 16 2007, 02:01AM
Location:
Posts: 1529

naa, more like a normal gun. TCAP is good because of its high burn rates, so while something else may give more power for a given amount, TCAP burns faster.

Backyard Skunkworks

Sat Jan 10 2009, 10:44PM

Registered Member #1262 Joined: Fri Jan 25 2008, 05:22AM
Location: Maryland, USA
Posts: 451

IIRC stoichiometric oxyhydrogen gas has a pretty high det velocity.

EDIT:
They're both really fast, but TCAP does burn at 5km/s and OxyH at 4km/s. Of course nitroamines can go past 9km/s...

Now, we better not get into any more specifics except... Don't try this at home!

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