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Mjöllnir - 1.5" porting Handheld Piston Hybrid

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: Technician1002 » Sat Nov 27, 2010 11:07 am

MrCrowley wrote:Edit: if you know of some German Fair-Use copyright laws I can use to dispute the claim I can try and get the ban removed.



With the industry attacking everyone with a very heavy hand, I pretty much don't use music anymore since they don't license it for what you want to use it for.

If you must use music, you may wish to simply re-do the video and use Creative Commons selections instead so they can't use copyright as a reason to nuke your work.

As long as music is a legal liability, I simply don't use music in my videos. As long as they don't want me to use their music, I no longer have a valid reason to buy music, so I don't buy it anymore.

Until the industry changes to how people use music in derivative works, and changes the license to match, they can starve since they way they sell music is pretty much of no use to me. The legal liability for using the product is way out of line.
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Last edited by Technician1002 on Sat Nov 27, 2010 11:15 am, edited 1 time in total.
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Unread postAuthor: ramses » Sat Nov 27, 2010 11:14 am

Quite amazing. I may be a bit of a wuss, But I am behind 1/2" thick Plexiglas whenever I shoot my hybrid. When I received my 2lb cannon ball sinkers, I was disappointed that they are about .060 too large for my barrel. As if my lack of barrel support could handle the recoil anyway...


Do you compensate for the ~7 PSI of propane in the chamber when you add the air? if not, you're running rich.
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Unread postAuthor: MrCrowley » Sat Nov 27, 2010 3:59 pm

I've actually been tempted to fire a cannon ball as well. I found one for $10 that was 40mm in diameter and about 300g. Not sure if I would ever have the balls to fire it though, I have a feeling it could do bad things to me or the cannon :P

Do you compensate for the ~7 PSI of propane in the chamber when you add the air? if not, you're running rich.

Yes, though I did notice it still ignites without compensating as well (I did a few tests running the cannon too rich and lean). I guess in the video it is a bit misleading as I said "fill the chamber with 132PSI of air" or whatever it was I said.
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Unread postAuthor: jackssmirkingrevenge » Sat Nov 27, 2010 7:05 pm

since a deodorant can is apparently a good fit in the barrel, might I suggest that sawing one in half will give you too excellent cup sabots, that could contain a fistful of BBs, marbles, nuts and bolts, nails...
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Unread postAuthor: MrCrowley » Sat Nov 27, 2010 7:11 pm

Ah, it wasn't a typical deodorant can but an empty plastic Hugo Boss roll-on can. I wish normal metal deodorant cans would fit but they don't.
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Unread postAuthor: jackssmirkingrevenge » Sat Nov 27, 2010 7:37 pm

Surely you can find one slightly less than 1.5" and make up the difference with duct tape?
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Unread postAuthor: MrCrowley » Sat Nov 27, 2010 7:41 pm

jackssmirkingrevenge wrote:Surely you can find one slightly less than 1.5" and make up the difference with duct tape?

I've rummaged through every aerosol can in my house to no avail :(
Not to mention duct tape gets expensive fast, it's like $10 a roll here :shock:
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Unread postAuthor: jackssmirkingrevenge » Sat Nov 27, 2010 7:48 pm

MrCrowley wrote:I've rummaged through every aerosol can in my house to no avail :(


No ladies in the house? The ones marketed at them tend to be rather phallic :roll: :D

Not to mention duct tape gets expensive fast, it's like $10 a roll here :shock:


Is it made from real ducks?

As an almost unrelated footnote regarding cutting aerosol cans in half, some people see sabots, others see stoves, what a lovely world we live in :)
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Unread postAuthor: MrCrowley » Sat Nov 27, 2010 7:51 pm

Hahahaha I know exactly what you mean, unfortunately even girl deodorant cans aren't great to use. They look about 32mm in diameter, I think that would leave too much duct tape exposed to the muzzle blast and it wouldn't be long before it is deformed severely.

Guess I'll have to bring a ruler next time i'm at the supermarket :)
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Unread postAuthor: jackssmirkingrevenge » Sat Nov 27, 2010 7:53 pm

MrCrowley wrote:Guess I'll have to bring a ruler next time i'm at the supermarket :)


HAHAHAHA!

"Sir, may I ask why you are taking the most phallus shaped cans from the ladies' aisle and measuring them?"

:D
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Unread postAuthor: MrCrowley » Sat Nov 27, 2010 8:17 pm

Think I won the dispute claim with YouTube, the video doesn't say it is blocked in Germany anymore.

Hopefully MRR can check that it's working.
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Unread postAuthor: Moonbogg » Sun Nov 28, 2010 12:01 am

Crowley, that cannon is impressive despite a smaller chamber volume. The beauty of the hybrid is appearant here. Does it make you nervous to fire it? Also, why would you think that firing a heavy round would damage the gun? Could the recoil bend the piping or something?
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Unread postAuthor: MrCrowley » Sun Nov 28, 2010 12:20 am

Does it make you nervous to fire it?

Most of the time, yes. It has got better since I've added the barrel support and 1" pipe on the chamber which makes handling recoil easier. If i'm shooting in a potentially dangerous situtation where there is a possibility of ricochets or I expect the shot to be louder than usual than I am quite nervous. In the video of the shots out at the holiday house I had no problem firing the cannon since the sound was minimal and there was little to go wrong.

Also, why would you think that firing a heavy round would damage the gun? Could the recoil bend the piping or something?

With the new barrel support i'm pretty confident the barrel will take projectiles as heavy as 300g in terms of the pipe flexing, my main concern would be with pressure build up and recoil.

Thanks for the compliments. If I get a chance I'll try extend the chamber with 2" pipe by another 40cm. Little worried about DDT though. :P
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Unread postAuthor: Moonbogg » Sun Nov 28, 2010 2:15 am

If the pressure is directing force straight back, what would cause pipe flexing? Hope i'm not getting too inquisitive here.

EDIT: Regarding the concern of pressure buildup. Would you expect the cannon to withstand the maximum potential pressure of the fuel load? Or do you consider it more like a firearm, where the pressure is manageable only if the projectile actually exits?
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Unread postAuthor: MrCrowley » Sun Nov 28, 2010 2:27 am

If the pressure is directing force straight back, what would cause pipe flexing? Hope i'm not getting too inquisitive here.

Nothing, now that I have a good barrel support but before the days of my barrel support the end of the barrel was flexing about 6-8". Enough that the tip of the barrel could almost touch the ground when the cannon was laying on the ground.

Now, I don't consider barrel flexing to be an issue.

Would you expect the cannon to withstand the maximum potential pressure of the fuel load? Or do you consider it more like a firearm, where the pressure is manageable only if the projectile actually exits?

Having a projectile certainly helps the piston refrain from bouncing back, which is a good thing. My concern was that with such a heavy projectile the peak pressure in the barrel would be the same but just last longer compared to if I fired the cannon without a projectile.

If I had the cannon ball I wouldn't be too concerned about firing it remotely. I can always buy another barrel. I don't think I would be able to handle ~9000J handheld though, perhaps I could, who knows :P
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