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Built a pneumatic 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: VH_man » Sat Dec 27, 2008 9:38 pm

who needs to synchronize them?]

Just record near the target the entire time, Then get a couple videos of dry fires! then string them together.

I use this technique ALL THE TIME for movies.

BTW, sweet gun. I like it.
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Unread postAuthor: MrCrowley » Sat Dec 27, 2008 10:36 pm

POLAND_SPUD wrote:well I must say I am quite surprised that there are hardly any replies

Ugh...fine...POLAND_SPUD you join the ranks of one of the few elite Spud-Gods. Happy? :D

I used to comment on cannons a lot more then I currently do, but like you said:
POLAND_SPUD wrote:I have my own life and things that I have to do


:)
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Unread postAuthor: jackssmirkingrevenge » Sun Dec 28, 2008 1:40 am

POLAND_SPUD wrote:well I must say I am quite surprised that there are hardly any replies... I thought a semi auto is something interesting... I knew that there were other guns using the same principle of operation before and this one is simple and very easy to copybut hey it's something quite new and original in a way... ok I'll stop complaining (I was expecitng soemthing like 'ohhh poland_spud kudosssss.... you are my god now' or something like that) :wink:


Presentation is important. A closeup video of a target being converted into a pasta strainer will work wonders, a thin metal or ply sheet for example. Remember, most of the people you're trying to impress are either de facto teenagers or are of an adolescent mindset ;)
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Unread postAuthor: ALIHISGREAT » Sun Dec 28, 2008 5:43 am

^^ he's right you know, a little damage can go along way :D
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Unread postAuthor: POLAND_SPUD » Sun Dec 28, 2008 4:34 pm

Ugh...fine...POLAND_SPUD you join the ranks of one of the few elite Spud-Gods. Happy?

@Mr Crowley hell yes!! :D

I am fully aware that this video doesn't prove that I am good at filming stuff :wink: nor that I am good at choosing a place for a shooting range... :wink: but never the less it's interesting in a way... you can see marbles in the air... and I promissed to post something today

http://www.youtube.com/watch?v=yynJmpUGYfw

plus it's the last video of the gun with such a smallish chamber - I realized that it was just way too small.. which I suppose was apparent to some of you.. the good thing was that it did well at silencing the gun so that I could fire it during christmas... now it has twice the chamber size (but still it's much less than half the barrel volume)

and lol sorry for complaining in my last post
I'll try to come up with something more spectacular than this
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Unread postAuthor: POLAND_SPUD » Thu Apr 23, 2009 1:45 pm

recently I've had some time to get back to this project...

so far I managed to replace the bolt with a better one (better flow) but there is still room for improvment - I think I can reduce the diameter of a nut that joins the bolt with the air cylinder by ~3mm - I hope that will give a noticable increase in power...


2 orings helped to eliminate double feds and prevent ammo from rolling down the barrel


I suppose that I'll replace the bolt with a fully restrictionless (does such a word exist? - uhmm now it does) one...

either my vertibolt (or some variation of it) or a rotating one (just like a ballvalve breech but air powered)


enjoy the vid
the distance was 15m
the target - 3/4 particle board
yeah quality ruins it - and I know I need to buy a real video camera

[youtube]http://www.youtube.com/watch?v=uU2XzddxWVY[/youtube]
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Unread postAuthor: Gippeto » Thu Apr 23, 2009 8:14 pm

More power is always a good thing. :D

I think it works pretty darn good. :salute: :)

Edited for shpellllingk :wink:
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Unread postAuthor: Mitchza89 » Thu Apr 23, 2009 8:16 pm

Very well done Poland. Very nice design. It looks like Frankenstein made himself a spud gun but no one in their right mind can bad mouth the performance and results.

Job well done. I can't wait to see the MkII version (There will ALWAYS be a MkII version :D)
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Unread postAuthor: jackssmirkingrevenge » Thu Apr 23, 2009 11:56 pm

Good stuff :)

Were you actually aiming though, shots seem to be going all over the place. And please, close-up target video!
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Unread postAuthor: POLAND_SPUD » Fri Apr 24, 2009 1:15 am

please, close-up target video
the camera was 4 meters from the target I'll try to get it closer but it won't help much - as I said I just have to buy a real camera as this one pretty much spoils everything..

I can't wait to see the MkII version
acctually that's (at least) version Mk XI :wink: - I''ll be satisfied when I build a restrictionless bolt/feeding mechanism

edit
I managed to cut a side hole in a 3/4" ball valve (most of them will fit a marble tightly -> ID = 16mm) it was easier than I thought...

I think that the toughest part of building a restrictionless rotating bolt will be converting linear motion of an air cylinder into precise and consistent 90 deg rotations

marbles get stuck inside the ball valve if it's not completely open- but apart from that the idea seems quite good
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Unread postAuthor: Brian the brain » Fri Apr 24, 2009 12:01 pm

Were you actually aiming though


What? never seen " the A-team"??

ta-ta-da-dummm...ta-ta-dummm


He's kicking up dirt intentionally!

( wich looks nice btw)
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Oh my friggin god stop being so awesome, that thing is pure kick ass. Most innovative and creative pneumatic that the files have ever come by!

Can't ask for a better compliment!!
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Unread postAuthor: POLAND_SPUD » Fri Apr 24, 2009 2:24 pm

in fact quite a lot of shots were on target but after penetrating the board they deflected in random directions.... in the original video I can see as new holes in it are cut... however, I suspect it might be hard to notice since the quality deteriorated even more on uploading the vid to youtube


since I expect to get at least one responce that goes like -> 'dude, I can't even see one hit. WTF is wrong with you?' so I ZIPed the original vid for those who can't see it...


but yeah I do think that kicking up dirt looks cool... if it hadn't been for this I wouldn't have uploaded it as it wouldn't look good enough (meaning you couldn't see much)

in fact dirt is quite useful for long range shots, well at least that's the only way to see >150m shoots
as soon as my neighbor plows his field I am gonna try some long range shots... :wink:
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Unread postAuthor: POLAND_SPUD » Wed Jun 24, 2009 6:49 am

ok I know it's double posting but I though it's a better idea to post here than to start a new thread...

I want to improve the loading mech which IMO restricts the flow a little bit too much and is rather uncomfortable to work with (copper fittings suck!!)

well first I wanted to try a rotating bolt mechanism (basically a 3/4" Ball valve + a rotary air cylinder) but the mass (and cost) of most rotary air cylinders is too great...



so the idea is as follows:
the general design of the gun stays the same... it uses a reciprotating aircylinder and there is a 90 deg turn from the QEV to the barrel.... however, in order to avoid flow restrictions by having a flow-through bolt and to reduce deadspace I decided to use a solid bolt that slides inside the breech part of the barrel...

the barrel will have two ports cut in it: one for ammo and one for the main valve... when compared with the previous design ammo port will be closer to the shooter/behind the T and the bolt will push it past the 'QEV' port... and... that's it

I hope the pic will help to understand what I mean as it's rather simple (though I know that diagrams are very easy to understand by their authors but not necessarilly by others

any ideas?? comments, opinions ??
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Unread postAuthor: daccel » Wed Jun 24, 2009 9:25 am

I had also concluded that a solid bolt is about as good as it gets to minimize restrictions and dead space.. soo I like :).

Obviously, the qev port must be slightly smaller than the ammo. I thought about drilling two holes maybe 2/3 barrel diameter side by side with a thin strip left between them for the ammo to ride on to prevent it from getting stuck in the valve port and not pushed forward enough. Only works without creating a restriction if your valve is bigger than barrel though.
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Unread postAuthor: THUNDERLORD » Wed Jun 24, 2009 10:19 am

I'm wondering how the heck I missed this awesome post???
I saw it but was out at the time and didn't have time to figure it out.
(like yourself, I have a life outside spudding, unfortunately sometimes).
IIRC there was a lot going on with pop-off piloting around the same time too.

About the vids, I was watching a vid of an ak-47 with 75rd. drums and even THAT, didn't show anywhere near the carnage of actually being there...missed all the secondary debri kicked up, the BaDOOM sounded more like "bang-bangs" and it missed a lot compared to being there.

Also with the partical board I caught that it was kicking up dirt after passing through target. One time I was shooting a frying pan stuck in mud with a .357 mag, and adjusted aim, because I thought I missed.Thought I Missed again...went to see WTF,
It was blasting through the steel without moving it at all!

Yeah, eliminating flow restriction from a drawing to components gets tricky. I was aware of flow restriction on a design I've been getting together myself. But now, I keep imagining a feed ramp opening or having the entire barrel move. It gets more complicated trying to keep the bolt from turning out of line, etc.
Looks like a great design there, on the new one, the pointy bolt should help feeding(?)..
Thanks
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