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Burst disks are crazy effective on mini combustions

Discuss miniature cannons built from things such as pill bottles and pen caps.
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Burst disks are crazy effective on mini combustions

Unread postAuthor: Insomniac » Mon Aug 18, 2008 5:40 am

Messing around with a really simple ping pong ball cannon I made out of my previously posted noisemaker, I found that by using two layers of aluminium foil as a burst disk I could get roughly TRIPLE the velocity I got with no disk (rough estimate by counting the frames between launch and impact with the body board)

[youtube]http://www.youtube.com/watch?v=W8agoTxTuhc[/youtube]
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I wonder how much deeper the ocean would be without sponges.
Right now I'm having amnesia and deja vu at the same time. I think I've forgotten this before.

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Unread postAuthor: rna_duelers » Mon Aug 18, 2008 5:45 am

You can really see the increase of velocity,maybe I will add a burst dics to my launcher...Hmm
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Unread postAuthor: CasinoVanart » Mon Aug 18, 2008 5:49 am

Very nice visual representation indeed, i love your post.
Not only does it prove that burst discs work it also takes the spudgunning world back to it's roots. Weel done Insomniac. 10/10.
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Unread postAuthor: psycix » Mon Aug 18, 2008 3:45 pm

Yes, the burst disks are effective, but how many times have you tried this?
With such a fueling method, shots tend to vary anyways.
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Till the day I'm dieing, I'll keep them spuddies flying, 'cause I can!

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Unread postAuthor: starman » Mon Aug 18, 2008 4:10 pm

Well yeahh... I'm surprised the burst disk gospel hasn't traveled further than it has. Discussion of them has tended to be related more to hybrids, I guess is the reason...just because it's a necessary part of one. However, they can provide night and day performance improvements to even simple cannons....as you very well demonstrated here.

...and basic burst disks are very easy to implement. I don't know.. :roll:
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Unread postAuthor: jimmy101 » Mon Aug 18, 2008 4:39 pm

A ping-pong ball cannon will be much more sensitive to a burst disk than guns that fire most other types of ammo. The lighter the ammo, and the lower the friction, the more a burst disk will boost performance. The heavier the ammo, and the higher the friction, the less of a performance boost you'll get.
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Unread postAuthor: Insomniac » Mon Aug 18, 2008 4:49 pm

Yeah, burst disk's arn't gonna work as well on regular cannons, but for certain guns like this one they work really really well.

@psycix: I have shot this at least 100 times on low-power mode, because I was shooting it across the room to my sister, and NEVER got anything near the power of the burst disk. Somtimes I would get a shot like in the vid, somtimes one that would go a bit slower, but the one it the vid was about as fast as it goes without a disk.

Also you would be surprized how accurate the fueling method is. Because of the way the nozzle mixes air, the air/fuel mix goes up to near perfect within 4 seconds, and additional gas slowly slowly makes it get richer (there must be more gas than air in the mix coming out of the nozzle) Roughly 4 seconds of gas makes this mini fire 99.9999 percent of the time.
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I wonder how much deeper the ocean would be without sponges.
Right now I'm having amnesia and deja vu at the same time. I think I've forgotten this before.

Add me on msn!!! insomniac-55@hotmail.com
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Unread postAuthor: starman » Mon Aug 18, 2008 5:00 pm

Insomniac wrote:Yeah, burst disk's arn't gonna work as well on regular cannons, but for certain guns like this one they work really really well.


It doesn't work well with spuds because they vaporize, but with just about any other hard, relatively light and loosish fitting ammo it will make a large difference. Yes, even regular, basic spray and pray cannons will see a marked improvement. Much more than moving from propane to MAPP alone.

Tennis balls already fit too tight for a burst disk to matter much. Softballs and baseballs while more massious can benefit some from a disk. Just about anything actually that doesn't squeeze a tight fit in the breech.
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Unread postAuthor: Insomniac » Mon Aug 18, 2008 5:23 pm

It all depends on the friction the projectile has on the barrel, and the length of the barrel. The ping pong ball gun has hardly any barrel, so the disk really helps. If the ammo was a tighter fit the difference wouldn't be as drastic.
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I wonder how much deeper the ocean would be without sponges.
Right now I'm having amnesia and deja vu at the same time. I think I've forgotten this before.

Add me on msn!!! insomniac-55@hotmail.com
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Unread postAuthor: starman » Mon Aug 18, 2008 8:04 pm

Insomniac wrote:It all depends on the friction the projectile has on the barrel, and the length of the barrel. The ping pong ball gun has hardly any barrel, so the disk really helps. If the ammo was a tighter fit the difference wouldn't be as drastic.


The barrel has to get out there to really unrealistic lengths on big bore spud guns and the ammo friction really high before you make up for a well matched burst disk.

Actually several features work to aid performance more than some people think. A mix fan, multiple spark gaps, good c:b ratio, burst disk etc, all interact with each other. All of these factors can make a big difference by themselves, but not as much in conjunction with each other. HGDT allows you to see the performance difference and interaction of these factors...it's really pretty cool to see it. :wink: To model a non-burst disk gun, put "0" in the disk failure entry.
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Unread postAuthor: Davidvaini » Mon Aug 18, 2008 8:14 pm

yeah, the performance of my Burst disk cartridges are great simply because they are burst disks. They are about the same size as your combustion and they shoot nerf balls crazy far.
[youtube]http://www.youtube.com/watch?v=ZbRLW4YPu54[/youtube]
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Unread postAuthor: nibbler125 » Sun Aug 31, 2008 8:33 pm

mabe it helps keep fumes inside of the chamber until ignition or mabe the ball exits the barrel before maximum power is reached. i would try a paper towel tube
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Unread postAuthor: 808AirsoftGunner » Sun Sep 14, 2008 3:20 am

could we have a picture of your gas filler? :shock: :D
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Unread postAuthor: Insomniac » Sun Sep 14, 2008 4:10 am

It is just a micro blowtorch like this one
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I wonder how much deeper the ocean would be without sponges.
Right now I'm having amnesia and deja vu at the same time. I think I've forgotten this before.

Add me on msn!!! insomniac-55@hotmail.com
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Unread postAuthor: littlebro05 » Sun Sep 14, 2008 6:09 am

Cool! I want to make one now... although I'm new to combustion type cannons. I understand the whole practical and theoretical side to it.

But where and how much does it cost to make a sparker / pizo lighter?
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It's Nerf or Nothing.

Don't start crying when I play this as my hobby, Paintball, Airsoft and Nerf are equally good hobbies, except you can play Nerf in public. Good day! Hmph!
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