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VERA: My very favorite gun

Built a hybrid cannon? Then post it here! This section is for completed, finished cannons that you have built. Please include pictures and information.
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Unread postAuthor: Fnord » Tue Mar 13, 2012 9:47 pm

Oh comm'on, if you're gonna use the de beers music you could have at least had a shot of you and the missus dancing around in highspeed, stuff being obliterated in the background, then maybe you get down one one knee and hand her a big diamond encrusted 'FIRE' button. :D

Anyway, I did see something interesting in there you might have noticed already. At 2:30 you can see a vortex ring exiting the barrel as the disk ruptures. It travels out a good ten feet from the barrel by the time the projectile emerges, then ignites instantly in time with sabot being 'caught' and the appearance of the muzzle flash.

At first I thought the ignition might have been caused by the shock wave Vera produces(somewhat like a thermobaric charge), but there is no delay visible in the timing of the flash emergence/ignition. It would have to be going at least around mach 10 to produce such an effect... detonation maybe?
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Last edited by Fnord on Tue Mar 13, 2012 9:49 pm, edited 1 time in total.
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Unread postAuthor: D_Hall » Tue Mar 13, 2012 9:47 pm

ramses wrote:Anyway, that is amazing. I love the impact flash, even at subsonic velocities.

What causes the delay in the fiery muzzle blast.

The bright flash isn't actually muzzle blast. That's the sabot hitting the sabot stripper... Aluminum burning; ignited by nothing more than kinetic energy.
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Unread postAuthor: D_Hall » Tue Mar 13, 2012 9:51 pm

Fnord wrote:Anyway, I did see something interesting in there you might have noticed already. At 2:30 you can see a vortex ring exiting the barrel as the disk ruptures. It travels out a good ten feet from the barrel by the time the projectile emerges, then ignites instantly in time with sabot being 'caught' and the appearance of the muzzle flash.

At first I thought the ignition might have been caused by the shock wave Vera produces(somewhat like a thermobaric charge), but there is no delay visible in the timing of the flash emergence/ignition. It would have to be going at least around mach 10 to produce such an effect... detonation maybe?


I believe that's nothing more than INTENSE refraction of the muzzle flash. Just as a star's gravity lens can make other stars appear where they are not, I believe that you're seeing INTENSE refraction due to density fluctuations in the air causing the muzzle flash light to be bent towards the camera.

Note: Not actually muzzle flash, but burning aluminum.
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Unread postAuthor: Fnord » Tue Mar 13, 2012 10:08 pm

I know what you're talking about, but I have to say that's a really crazy effect. Seems fairly likely, though. That little flash doesn't seem to behave quite right somehow. No illumination on the ground under it, and it seems like it's trying to travel backwards.
I definitely see the aluminum igniting, just can't tell how much of the flash it accounts for. What's left of the sabot afterwards?

(Oh, and IIRC in one of your old threads someone mentioned a PR stunt involving a fifty pound bag of potatoes. There's one for the discovery channel, haha.)
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Unread postAuthor: jackssmirkingrevenge » Wed Mar 14, 2012 1:07 am

Image

That brought a genuine slight tear to my eye.

*sigh*

Amazing stuff, and ∞ kudos to you for taking the concept to its logical conclusion.

How much do you calculate a shot costs in terms of material and man hours?

Given the "anything that fits in the bore" capability, I know what I'd be doing all day at work :D

Fnord wrote:Oh comm'on, if you're gonna use the de beers music you could have at least had a shot of you and the missus dancing around in highspeed, stuff being obliterated in the background, then maybe you get down one one knee and hand her a big diamond encrusted 'FIRE' button. :D


[youtube]http://www.youtube.com/watch?v=c82z_bxy60E&feature=related[/youtube]

:D
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Last edited by jackssmirkingrevenge on Wed Mar 14, 2012 2:35 am, edited 1 time in total.
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Unread postAuthor: natas » Wed Mar 14, 2012 2:33 am

oh my word.... !!! no wonder the military have observed it from satelites :-)
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Unread postAuthor: pneumaticcannons » Wed Mar 14, 2012 4:43 am

HOLY...... the metal ignited from pure KE?!?!?! I don't think any of us have been Image
ing like I am since Larda's hybrid.... Not to mention the amazing HQ high speed...
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Unread postAuthor: jrrdw » Wed Mar 14, 2012 6:43 am

Very well done! Now, who out that way has junk busses or old dump trucks to shoot at?
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Unread postAuthor: cfb_rolley » Wed Mar 14, 2012 7:40 am

That is the greatest thing I have ever seen in my entire life.

I've also seen the amount of time and effort that went in to this, and to me it looks totally worth it! well done!
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Unread postAuthor: D_Hall » Wed Mar 14, 2012 8:42 am

jackssmirkingrevenge wrote:How much do you calculate a shot costs in terms of material and man hours?


It's mostly man hours manufacturing the burst disc and projectile but... She costs about $6,000 per shot.


And thanks, everybody. Don't think I don't remember when the idea was little more than a spudder joke. That I was able to actually make it happen obviously means a lot to me, but I don't think I would have seriously pursued it without feedback refining the design from ya'll.
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Unread postAuthor: jackssmirkingrevenge » Wed Mar 14, 2012 9:41 am

D_Hall wrote:It's mostly man hours manufacturing the burst disc and projectile but... She costs about $6,000 per shot.


That's actually pretty reasonable - if one is testing the impact performance of an air-dropped bomb it's certainly more economical to fire it out of this than to actually drop it from an aircraft, especially given accuracy concerns. I gather this is the sort of work it will be used for?

Aside from supersonic sacks of spuds, of course ;)
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Unread postAuthor: D_Hall » Wed Mar 14, 2012 10:13 am

jackssmirkingrevenge wrote:That's actually pretty reasonable - if one is testing the impact performance of an air-dropped bomb it's certainly more economical to fire it out of this than to actually drop it from an aircraft, especially given accuracy concerns. I gather this is the sort of work it will be used for?


I could nit pick... But yeah, you've got the gist of it.
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Unread postAuthor: wyz2285 » Wed Mar 14, 2012 10:27 am

I almost cried when I watched the bullet´s impact :thumbright:
I love your job :D
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Unread postAuthor: POLAND_SPUD » Wed Mar 14, 2012 1:27 pm

lol shouldn't we post it on hackaday ? (as well as SB15's hybrid)
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Unread postAuthor: s0ka » Wed Mar 14, 2012 2:32 pm

Wow great beast .......... I don't know what to say it's so incredible :D

I would like to ask you something about your welding and the pipe .

So what is the pipe shedule? And what kind of welding have you used? TIG or high pressure stick welding?
So thanks if you have few second to reply.
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