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Starting a project to break the SOS :)

Post questions and info about hybrid (compressed gas with fuel) powered cannons here. This includes discussion about fuels, ratios, ignition systems, build types, safety, and anything else relevant.
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Starting a project to break the SOS :)

Unread postAuthor: Dave_424 » Mon Jun 22, 2009 7:20 pm

Right guys, I have a odastream bottle that is tested to 3600 psi and am going to build a high pressure hybrid.

I will tap a 1/4" thread into the back of the bottle and if I think that the walls are too thin, then I will weld it aswel. I will have a homemade sparkplug in a 1/4" tee and a male quick connect with isolating ball valve to fill and fuel the launcher.

I will have a 1m long 8mm barrel and shoot 8mm ballbearings. This cannon will have some serious potential. From a regular 1x mix, this thing has more power than my new Air Arms S410 DAMN! but at 15X mix, it is around 1800 FPS (modled in HGDT but prorably a but excessive), From modeling these numbers into my balistics program, it has 244 foot pounds at 15X and only drops 2 inches at 100m


What do you guys think?
Dave
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Last edited by Dave_424 on Mon Jun 22, 2009 8:38 pm, edited 1 time in total.

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Unread postAuthor: twizi » Mon Jun 22, 2009 7:57 pm

its very possible to break the the sos

people have got golf balls to be super sonic i think u can do it
today i made 7mm hybrid if my camrea works ill show wat happens when a tic tac hit a 1/4 plate at the sos
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dont play with airsofter with 1000$ gun and play with a 5 dollar pair of glasses
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Unread postAuthor: Dave_424 » Mon Jun 22, 2009 8:01 pm

Yeah I think it will be relativley easy to do :P (Hopefully)

Man that would be awesome to see, I bet it is really devastating, pretty surprising to see what it will do.

Anyone got any ideas on the amount of penetration or steel plate from either a steel dart or 8mm ball bearing at the velocities posted above?

Dave
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Unread postAuthor: daccel » Mon Jun 22, 2009 8:21 pm

Can't wait to see it :). Are you planning on using a burst disk or piston?

Can't give you an idea on amount of penetration, but make sure you don't stand inline with the trajectory if the plate is too thick. Hate to find out the hard way how fast a supersonic bb bounces off!
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Unread postAuthor: pizlo » Mon Jun 22, 2009 8:24 pm

For penetrations you really need tool grade steal and pointy.
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Unread postAuthor: Dave_424 » Mon Jun 22, 2009 8:25 pm

Thanks
It is inline with burst disk.

Somehow, I need to find a repeatable burst disk for a 1cm opening that will burst at about 1400 psi. I might try a soda can

I'm hoping for awesome penetration because i has more then twice the energy than a .22LR so should be able to punch through atleast 2 2x4's hopefuly more

Dave

EDIT: I will get some centre punches and grind them to a nice point. Fairly expensie ammo but I can get someold ones for free and the will only be fired a few times
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Last edited by Dave_424 on Mon Jun 22, 2009 8:27 pm, edited 1 time in total.

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Unread postAuthor: THUNDERLORD » Mon Jun 22, 2009 8:27 pm

Afterwards will you learn to spell and type???
YMBASI: You were building hybrids before you could spell or type. :P
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-----SPEED,STRENGTH, AND ACCURACY.-----
"Procrastination" is five syllables for "Sloth".
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Unread postAuthor: Dave_424 » Mon Jun 22, 2009 8:29 pm

Urm..... isn't that a bit harsh??

It is 2:27 in the morning here so cut me a bit of slack

You might just be saying it in a light hearted way but it is hard to tell

Dave
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Unread postAuthor: THUNDERLORD » Mon Jun 22, 2009 8:37 pm

It was a joke.
But seriously, I thought I was bad about that. :roll:
Atleast you could put a ' before roject like " 'roject"...Might be cool redneck speak like:,"I'm builin' a 'roject"...
"yunna ear 'bout it? Yuount? Yountoo"..."Ya do? Good Ere's a 'oW-To" IDK. That's how the name "K-Bar" knife came up anyway 8)

EDIT: "EDIT" button can be your friend.
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Last edited by THUNDERLORD on Mon Jun 22, 2009 8:41 pm, edited 1 time in total.
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Unread postAuthor: daccel » Mon Jun 22, 2009 8:40 pm

I used a single layer of pop (read: soda :lol:, what just me?) can at 8x in approximately 1cm burst disk, but the holder was a flare fitting so I suspect it may have weakened it around the edge, which a union wouldn't do.

Anyway, probably a good starting point to try.
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Unread postAuthor: Dave_424 » Mon Jun 22, 2009 8:41 pm

HAHA i actually didn't notice the title, I am also typing on a laptop which had a drink spilled over it, unfortunatley it didn't break so I could get a new one but now the keyboard is real sticky and it will miss out letters when I am typing fast.

That is pretty interesting about k-Bar

Dave
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Unread postAuthor: KineticAmbitions » Mon Jun 22, 2009 8:45 pm

I wouldn't count on HGDT to be inaccurate in its predictions - it accurately modeled Larda's HyGaC20 even at muzzle speeds of over 900m/s, which is approaching the SOS in the post-combustion gases.

I have two questions: how will you reach 15x in the first place, and how will you ignite it? If you are using oxygen-enriched mixes to reach 15x, the HGDT predictions may be inaccurate. Judging by the tanks I've seen cut open / ripped to shreds, welding of the threads will almost certainly be a necessity.
Also, make sure to get a sturdy ball valve with a decent temperature rating. The only hybrid I've ever seen first hand used a 2000psi valve, and later a 6k psi valve rated for up to 1000 degrees Fahrenheit (because the 2k psi one developed a leak).

The closest I've seen to what you describe in terms of the projectile was a 9.5mm ball bearing at 1400fps, which left a small crater about 10.5mm in diameter and 4 - 5mm deep in a 6.5mm normalized steel plate. There was visible deformation of the back of the plate in the form of a hemispherical protrusion of roughly the same dimensions as the "crater" on the front of the plate. The bearing was not recovered, but I suspect that no more than twice that speed would be required for convincing punch-through of the plate. Newton's approximation of impact depth sets a limit of penetration for an 8mm steel bearing at 8mm of steel plate, and at speeds most of us are likely to achieve, I can't see that limit being exceeded (eventually, sudden dissipation of huge levels of kinetic energy would essentially explode the target, resulting in the failure of the approximation at what amount to completely ludicrous impact speeds).

For burst disks, you will never run out of aluminum foil, and you can always get the burst strength you need.

If the dart is properly hardened and tempered, moving at 500m/s, it will easily make its way through the plate. If it is not properly hardened and tempered, it will either shatter on impact, or show impact characteristics similar to those of a hot lead brick, depending on whether it is too brittle, or too soft. Center punches make great armour-piercing cores for rounds, and sometimes even stay intact after penetrating a steel target.
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Unread postAuthor: Dave_424 » Mon Jun 22, 2009 8:53 pm

Woah thats a mighty long post .

Okay then, I will reach 15X with my fridge compressor capable of 60 BAR

I might not even take it to 15X for a while, I will drill the hole in the tank ready to tap the threads and see what the wall thickness looks like. I am just afraid that if I atempt to weld it, I might just end up melting holesin my chamber.

However this week I am welding together a buggy frame so I will get lots of practice.

Looks like ball bearings aren't that good in terms of pnetration so i will use the centre punches when looking for maxinum penetration


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