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| CpTn_lAw |
 Posted: 03/09/2008 13:22 PM Post subject: |
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Your friendly scientist
Joined: 11 Sep 2005
Posts: 933
422.24 Spud Bux
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| That is quite a super lot of power here...but in a way, it's a great pain in the a** to build a cap. bank this big, even to get such killer results.
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| DYI |
| Posted: 03/09/2008 13:32 PM Post subject: |
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Rear Brigadier
Joined: 07 Jul 2007
Posts: 2692
2268.21 Spud Bux
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| I'm very thankful that someone made one of these, because mine will never be this powerful, and at the rate I'm going, it'll literally be years before I complete it. Supersonic wouldn't surprise me at all with a design like this.
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| Larda |
| Posted: 03/09/2008 23:01 PM Post subject: |
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Donating Member
Joined: 18 Jul 2007
Posts: 108
274.88 Spud Bux
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I made another more successful attempt to measure the velocity today.
I added several layers of sheet metal to the pendulum to make it "bullet proof".
The projectile penetrated two pieces of 20mm wood, two pieces 3mm aluminium, and finally 5mm of steel before it disintegrated.
In this test i charged the capacitors to their surge rating 1350v, for a total energy of 36,5Kj.
High Speed video of the test, its captured at 100FPS but the resolution is lower.
http://www.vimeo.com/769985
The failed test earlier.
http://www.vimeo.com/770135
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| Damage by a 90g 12mm Solid Carbide projectile. |
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| The projectile turned into shrapnel after impact. |
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| Damage by a 90g 12mm Solid Carbide projectile. |
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| MrCrowley |
| Posted: 03/09/2008 23:21 PM Post subject: |
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Kaleun
Joined: 23 Jun 2006
Posts: 8978
9125.29 Spud Bux
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 HOLY MOTHER OF GOD!
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| Killjoy |
| Posted: 03/09/2008 23:36 PM Post subject: |
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Brigadier General
Joined: 11 Nov 2006
Posts: 1058
104.28 Spud Bux
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| Good god, thats beautiful.
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| chartreusesnot |
| Posted: 03/09/2008 23:50 PM Post subject: |
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Staff Sergeant
Joined: 05 Jun 2007
Posts: 111
25.21 Spud Bux
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| anybody else noticing the completely massive recoil? It appears to be launching bricks and those square metal bars backwards...
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| Larda |
| Posted: 03/09/2008 23:59 PM Post subject: |
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Donating Member
Joined: 18 Jul 2007
Posts: 108
274.88 Spud Bux
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| chartreusesnot wrote: | | anybody else noticing the completely massive recoil? It appears to be launching bricks and those square metal bars backwards... |
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| chartreusesnot |
| Posted: 03/10/2008 0:07 AM Post subject: |
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Staff Sergeant
Joined: 05 Jun 2007
Posts: 111
25.21 Spud Bux
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| Dude... whats happening in that picture? did the recoil split that brick...?
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| Rokmonkey |
| Posted: 03/10/2008 0:16 AM Post subject: |
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Corporal
Joined: 28 Feb 2007
Posts: 73
201.96 Spud Bux
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| Holy Mary mother of God...
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| Novacastrian |
| Posted: 03/10/2008 0:31 AM Post subject: |
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Bloody Aussie
Joined: 11 Aug 2007
Posts: 1622
116.11 Spud Bux
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I herewith change my sig, sorry DYI but this truly takes the cake   
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| Copperboy |
| Posted: 03/10/2008 1:21 AM Post subject: |
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Sergeant
Joined: 29 Dec 2005
Posts: 93
253.93 Spud Bux
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Satan i Gatan!!
How did you machine your "chamber"? Nice work!
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| jackssmirkingrevenge |
| Posted: 03/10/2008 4:26 AM Post subject: |
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aspiring machinist
Joined: 15 Mar 2007
Posts: 18018
32418.63 Spud Bux
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That's just spectacular, congratulations!
I love the way the chequer plate pattern is imprinted on the wood in this photo - amazing stuff, keep it up
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| Ragnarok |
| Posted: 03/10/2008 8:08 AM Post subject: |
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Lord of Karma
Joined: 19 Dec 2006
Posts: 5158
16113.53 Spud Bux
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Well, that sort of puts things into perspective. DYI has been well and truly beaten on the penetration front.
From that video, and guessing from the markings on your back board, it looks like you're doing about 260-270 m/s (860-880 fps), which is around 3200 Joules (2400 ft-lbs) of kinetic energy. That's a phenomenal amount from a 12mm barrel of that length, and it would seem you're achieving an average pressure of around 10000 psi - possibly more, I'm not sure how long your barrel is, so I guessed around 40 cm from the picture in the opening post - which is a full order of magnitude above anything anyone else has yet achieved (at least, that I can think of).
So, it's not actually supersonic, only about 80% of the way there, but no doubt if you used a projectile of somewhere under 50 grams, you could manage to break the sound barrier.
It's also a respectable 11% efficiency. Ooh, I can see more of these being made.
You sir, have what is no doubt one of the most kick-ass spudguns ever.
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| starman |
| Posted: 03/10/2008 8:40 AM Post subject: |
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Big Daddio
Joined: 11 Dec 2007
Posts: 3076
7546.07 Spud Bux
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I would be interested in the possibililty of adding some water in with the aluminum powder, possibly somewhat little less powder to make room in your chamber. If you added a minimalist (or more even) burst disk, you could experiment with different slurry mixtures and see what works best.
This is based on the aluminum powder flashing to plasma and thus flashing the water to steam. The military has been prototyping the plasma/steam combo for several years and it supposedly has multimach potential if configured correctly. It may require more power to work properly than you have here, but, maybe not.
Again, very impressive work!
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| DYI |
| Posted: 03/10/2008 8:55 AM Post subject: |
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Rear Brigadier
Joined: 07 Jul 2007
Posts: 2692
2268.21 Spud Bux
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I tip my hat to you sir, you've achieved what most of us will only ever dream of 
I have to get my ass in gear on the [redacted] project now...
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