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| noname |
 Posted: 06/02/2007 20:43 PM Post subject: Supersonic? |
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Mr Vortex
Joined: 10 Apr 2006
Posts: 2509
2698.56 Spud Bux
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Well, I've been trying different types of high pressure burst discs lately. My gun stopped working as a hybrid, no idea why. I have my meter length and pressure set correctly according to SpudTool (AdvancedSpuds) and FuelTool (BurntLatke). It's all steel, so I've been shooting it at ridiculous pressures as a pneumatic. I used two layers of aluminum soda can today, as a burst disc. They held 350 psi! I couldn't pump further with my bike pump (I was literally jumping on it), so I waited. After a minute or two, the thing went off, totally randomly. The steel ball bearing went through 6 soda cans, two layers of 1/2" plywood (the backstop  ), through my tin shed, out the other side, and finally left a 1/2" deep dent in my 3/4" plywood fence. It was extremely loud, louder than anything I've ever heard. Usually the gun sounds like a rifle, but this shot was louder than a shotgun. I can barely hear now.
Give me your opinion, was it supersonic or not.
Almost forgot, this gun's barrel is 10 feet of 1/2" PVC for those who don't know.
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| Both layers on top of each other |
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| pyromaniac |
| Posted: 06/02/2007 20:45 PM Post subject: |
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Brigadier General
Joined: 27 Feb 2007
Posts: 813
890.79 Spud Bux
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| i say hell yeah is was. horay for a sale at OSH.
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| hi |
| Posted: 06/02/2007 20:58 PM Post subject: |
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Major General
Joined: 01 Feb 2007
Posts: 1456
1019.01 Spud Bux
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| Redcoat |
| Posted: 06/02/2007 21:04 PM Post subject: |
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Bobblehead Doll
Joined: 13 Feb 2007
Posts: 843
369.88 Spud Bux
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wow  . thats is a massive! It went through all that?
Thats AWESOME!
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| SpudBlaster15 |
| Posted: 06/02/2007 21:06 PM Post subject: |
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Human blast shield
Joined: 18 Oct 2006
Posts: 1539
11.03 Spud Bux
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GGDT says you hit somewhere in the vicinity of 900fps.
That was one hell of a shot, but I am not surprised. A 10 gram piece of steel traveling at 4/5 the speed of sound will do a ton of damage to most things.
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| spudthug |
| Posted: 06/02/2007 21:42 PM Post subject: |
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Gangster Kitten
Joined: 26 Feb 2007
Posts: 974
609.33 Spud Bux
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i almost got supersonic with my jme-45 gun...i got 1054 fps with a 1 inch marble....at 100 psi...if i went to 120 there is no doubt i would have gotten supersonic..
sadly my compressor wont fill the massive gun over 105 psi..
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| VH_man |
| Posted: 06/02/2007 21:58 PM Post subject: |
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Major General
Joined: 09 Dec 2006
Posts: 1334
1953.86 Spud Bux
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| wow.................... that sounds pretty powerful. i would invest in a shock pump and send things at the speed of sound with simple pneumatic pressure, and prove that it can be done............
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| SpudBlaster15 |
| Posted: 06/02/2007 22:10 PM Post subject: |
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Human blast shield
Joined: 18 Oct 2006
Posts: 1539
11.03 Spud Bux
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| spudthug wrote: | i almost got supersonic with my jme-45 gun...i got 1054 fps with a 1 inch marble....at 100 psi...if i went to 120 there is no doubt i would have gotten supersonic..
sadly my compressor wont fill the massive gun over 105 psi.. |
How did you come up with that number? I am doubtful that your JME-45 could accelerate a 1" diameter marble (probably on the order of 20 grams) to within 50fps of the speed of sound, at 100psi.
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| noname |
| Posted: 06/02/2007 22:16 PM Post subject: |
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Mr Vortex
Joined: 10 Apr 2006
Posts: 2509
2698.56 Spud Bux
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I'll keep trying, as soon as I can get it to work as a hybrid. 6 or 7x will produce enough pressure to get it going that fast. Over the summer, I also plan on doing hybrid C:B ratio tests, with a 40 or 50 foot barrel, and replicating Latke's tests (cutting 20% off after ever round of shots).
I plan on starting with a 50 foot barrel, shooting 3 shots at 1x, 3 shots at 2x, 3 shots at 4x, 3 shots at 5x, then cutting off 20%. I'll keep doing this until I get to a 1 foot barrel.
Damn, I'm gonna go through soooo many burst discs. 
Oh, forgot to mention, check out that amazing burst!
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| spudthug |
| Posted: 06/02/2007 22:19 PM Post subject: |
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Gangster Kitten
Joined: 26 Feb 2007
Posts: 974
609.33 Spud Bux
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| my marble was 10 grams...idk i didnt come up with it ggdt did...but anyway..no name u say that u only put 350 psi of air in there? wow...try a 5x mix and u could probably get around 1000 fps...im not a hybrid expert but isnt it pretty easy to reach 350 psi with a hybrid?
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| PVC Arsenal 17 |
| Posted: 06/02/2007 22:20 PM Post subject: |
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WITTY PHRASE
Joined: 27 Mar 2006
Posts: 1232
748.69 Spud Bux
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That sounds like one hell of a shot! Lucky that crap didn't bounce off something and fork you up.
Burst disc guns continue to fascinate me. I have yet to see any valve match the speed of burst discs. The only trouble is finding the perfect one for your gun.
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| noname |
| Posted: 06/02/2007 22:27 PM Post subject: |
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Mr Vortex
Joined: 10 Apr 2006
Posts: 2509
2698.56 Spud Bux
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By sticking on a peak pressure guage, I figured (when it worked as a hybrid) 1x would get me about 90 psi, 1.5x would give about 140 psi, 2x would get me about 170, 2.5x got around 215, 3x about 250, 4x about 310, and I didn't test past that.
I wouldn't recommend using soda can burst discs for PVC guns, because one layer takes around 170 psi to burst.
PVC Arsenal, I got hit by one of the bearings once. At a 2.25x mix, the ball bearing got shot through 4 soda cans and hit a piece of steel pipe that was lying around. It gave the pipe a 1/4" deep dent, bounced back, and tapped me on the kneecap.
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| spudthug |
| Posted: 06/02/2007 23:01 PM Post subject: |
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Gangster Kitten
Joined: 26 Feb 2007
Posts: 974
609.33 Spud Bux
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@noname: what is the best burst disk u have used at a 4x mix? also waht mix are milk bottles good for?
also does anyone know how to wire up a stun gun to 2 spark plugs?? i will be posting a thread asking this question soon reply there..
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| A-98 |
| Posted: 06/02/2007 23:11 PM Post subject: |
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Pussy Lover
Joined: 27 Apr 2006
Posts: 907
135.08 Spud Bux
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hm.... i need to build a hybrid.....badley....
also....
spudthug.
i
cannot
allow
you
to have an avatar cooler than mine....
i marvel in the presence of your avatar.
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| Velocity |
| Posted: 06/02/2007 23:14 PM Post subject: |
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Brigadier General
Joined: 07 Feb 2006
Posts: 948
25.24 Spud Bux
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I elaborated on the gangsta theme....
anyways...
PVC Arsenal, I doubt that there IS a valve faster than a burst disk. Full flow, rapid opening... can't beat it.
The only valve better than a burst disk valve... is a BIGGER burst disk valve.
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