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once more, burst disk holders!

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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Unread postAuthor: psycix » Fri Mar 20, 2009 1:22 pm

So you need a backstop?
I'd go for a good amount of plywood, spaced about a feet from each other, but angled, not parallel. So that when the ball bounces back on the last board (which may be harder, like sheet metal) it goes back into the wood, but not through the hole it earlier made.
Cover this box of truth with something to be extra safe.
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Unread postAuthor: SpudFarm » Fri Mar 20, 2009 3:33 pm

i won't buy a flange because self made is allways best.

backstop is pretty simple, i shoot into the woods and the ball will probably go into the ground or get pulverized.

what i really wonder is what you would place a 2400fps golf ball in if you had only one shot that day. remember that i have a high speed camera.
but things as a water mellon is not a good target. i wan't something that makes a good impressive video so i can get the cannon posted
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Unread postAuthor: D_Hall » Fri Mar 20, 2009 7:34 pm

SpudFarm wrote:i won't buy a flange because self made is allways best.

I find just the opposite to be true - when one is discussing similar design applications. Why? Because there are people who've dedicated their careers to the optimization of a particular gizmo. You (or I) are mere amateurs when it comes to designing a gizmo. Their's is almost always better... *IF* the purpose of that gizmo matches the purpose you intend to use it for. Admittedly, our purposes around here rarely match purposes in industry, but it's not unheard of either.

And as a bonus, since they make 'em by the bazillion, they're almost always cheaper by the time you account for all the hidden costs.

what i really wonder is what you would place a 2400fps golf ball in if you had only one shot that day. remember that i have a high speed camera.
but things as a water mellon is not a good target. i wan't something that makes a good impressive video so i can get the cannon posted

Why don't you think a water mellon is a good target? I mean, the simple apple (vs. 30 cal rifle) is probably the most famous target in the history of high speed photography. Seems like a water mellon would be a reasonable scale up.

I must say, however, that I doubt you have the kind of camera that could do a 2400 fps golf ball justice. I mean, we have those at the office. They cost on the order of $50k for a cheap one. If you've got that sort of funding at your disposal you may as well just make your own custom breech mechanisms and such. My point being that ballistic photography is best when the camera is fast enough to provide decent tracking of the projectile. Thus, the most impressive videos may actually result with a SLOWER golf ball.
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Unread postAuthor: psycix » Sat Mar 21, 2009 1:43 pm

Some electronics like an old TV, microwave or SNES will do.
Flying pieces of circuit board.

Or what about a pile of action figures?

I agree that a watermelon is not a good target. Its just sooooo classic to shoot fruit or vegetables. Something more unique would be awesome.
You could also put down a tray of beer cans (full) and see how it smashes its way through 6 rows of 4 cans. Then drink the undamaged ones :)

You can also fire it 89* upwards and just shoot it into orbit. (figuratively)
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Unread postAuthor: starman » Sat Mar 21, 2009 2:08 pm

Watermelons make beautiful (and relatively safe) damage videos. How about 3 or 4 watermelons behind each other. Yeah, they are used a lot but you can get creative... :wink:

You're going to need target material that's fairly small to medium and softish to get good results. Golf balls tend to just want to make a clean hole in something and move quickly out of the frame or ricochet back at you.

Actually, Gallagher with his infamous Sledge-O-Matic has made blasting watermelons his life's work.

[youtube]http://www.youtube.com/watch?v=rfQRnAb5cdw[/youtube]

He also found that lettuce heads give great damage results, although not in this particular video.
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Unread postAuthor: SpudFarm » Sun Mar 22, 2009 2:03 pm

i can make the flange to be perfect for my use, if you buy one it won't be made for burst disks.

what would a watermelon be if you compare it to something like a TV with a sheet of C4 on it? though with a primary since i know you would have pointed that out.

what i want is a video that gets the point to the line, a rifle can turn a mellon to steam but i can do more. mabe not at penetration but i can transfer more energy.

Yeah the TV's sounds good but i will add some effects. and i have to get the muzzle flash!

not everything is meant to be safe, when you have a gun that can be dangarous you should make a remote to handle that danger. a golf ball won't do to bad damage to a house.
i do have wireless ignition now.

thanks! i look forward to get my ass onto the forum again!
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Unread postAuthor: psycix » Sun Mar 22, 2009 6:49 pm

You could also blast bricks out of a wall, or fire multiple shots at an old car, maybe even a buckshot of ball bearings.....
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Unread postAuthor: D_Hall » Sun Mar 22, 2009 9:46 pm

SpudFarm wrote:i can make the flange to be perfect for my use, if you buy one it won't be made for burst disks.

Ummm.... Would you like to make a wager on that?

Image

what would a watermelon be if you compare it to something like a TV with a sheet of C4 on it? though with a primary since i know you would have pointed that out.

More informative. TVs are made in about a zillion different ways. What would destroy one TV may not do much to another. That's the appeal of a "standard" target. True, mellons may very in size, but a 10 lbs water mellon isn't going to behave that much differently than an 11 lbs water mellon. But how does a Sony compare to an Philips TV? I have no idea... Thus, you blowing a hole in one doesn't really tell me much.

Yeah the TV's sounds good but i will add some effects. and i have to get the muzzle flash!

And while adding effects might make for "good TV" it will totally elliminate any objective measurements you may desire. I mean, Hollywood can make a hand grenade take out a city block with effects. How will the viewer know the difference between what youre gun is capable of and what your video editing skills are capable of? If you want to wow 'em with the gun, keep it simple (Note: Wowing people with weapons IS what I do for a living).
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Unread postAuthor: starman » Sun Mar 22, 2009 10:20 pm

D_Hall wrote:
SpudFarm wrote:i can make the flange to be perfect for my use, if you buy one it won't be made for burst disks.

Ummm.... Would you like to make a wager on that?

Image


Good point Dave. Spudfarm, I think you missed these....designed to fit in your flange as shown in Dave's pic above.
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Unread postAuthor: D_Hall » Sun Mar 22, 2009 10:32 pm

starman wrote:Good point Dave. Spudfarm, I think you missed these....designed to fit in your flange as shown in Dave's pic above.

There are also disks designed to be used in JUST a flange set up (no holders required), but that wasn't my point so I didn't look that hard for 'em.
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Unread postAuthor: SpudFarm » Mon Mar 23, 2009 10:41 am

i said that i will make my flange, and why would i pay the shipping for a 2" chunk of steel when i can make an identical one?

and i thought you understood that i would not shoot a 50" brand new Plasma TV, and a Sony and Phillips CRT screen would behave just the same after my messurements, remember that i am a normal guy trying to get some speed on the golf ball and get a good smile after good results, not making a damage presentation for NASA on how their rockets would behave if they hit a TV (of course a Sony 32" CRT widescreen).

effects would be explosives, NOT fake. i didn't want to say that word but i had to. C4 sounds more common and inocent, that is why i used that word before.

i don't really understand what you are trying to say Dave? would it really matter if the Sony TV got one more crack? no it would not.

enough of that, and don't think i flame you i did just don't understand why you had to point out the TV part.

Psycix: i do have an old car! though not before the snow has gone away from it.
the buckshot idea will probably be done, but i think bolts would be cheaper.
imagine how cool 300g of bolts would be if they traveled a distance and then hit the car and you hear the nice "smack" and all the windows break!

Cheers ;)
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Unread postAuthor: psycix » Mon Mar 23, 2009 6:21 pm

Don't use explosives in the target of a spudgun.

Shoot a TV with a spudgun: sure.
Blow up a TV with C4: sure.
Both: nahhh.

What is the point of putting C4 in the target? It is about what the gun can do, not how you can set off a charge with a spudgun.
Using explosives will look like the spudgun didnt have much effect by itself.

We want to see how a golfball destroys something with pure kinetic energy. Using explosives at the same time is what I call cheating. The damage no longer represents the capabilities of the gun.
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Unread postAuthor: SpudFarm » Tue Mar 24, 2009 10:24 am

you don't understand, i will make my stuff, then flatten it so it is about 0.5mm thin or thinner. then i will paste it to the screen to get a better effect on the video. the screen will already have been broken when it goes off so the only thing that will be different is that the glass is spread throughout the place.

but sure! if you want to see it with only a golf ball instead i will do that, a steel plate hit with a APFSDS round would fill that effect better.

if i get it to work good enough i will try to shoot a tree with a golf ball to. i can't really think of it bouncing back. then i will try to do the distance shot if i can't figure out anything better.

Thanks :)
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Unread postAuthor: psycix » Tue Mar 24, 2009 12:47 pm

Sounds gooood! When can we expect these damage video's (and pictures)?
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Unread postAuthor: SpudFarm » Tue Mar 24, 2009 5:00 pm

depends on how much work it is to do on the shop at friday. in worst case i can't even start at it. the chance is that i can draw it up real quick and pay the company to make it while i am there just like i would if i did not work there.

after that i can't really think out any excuse that i can slow everything down with. meter and gun is complete if i remember right, just collecting dust in my shed.
i need to get an air comp to the shooting range though but that is simple.

BTW i will have to get a TV before i can make some real good videos but i will test in the meanwhile.

thaaanks Psycix :P
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