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a real automatic valve or system !

Post questions and info about pneumatic (compressed gas) powered cannons here. This includes discussion about valves, pipe types, compressors, alternate gas setups, and anything else relevant.
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a real automatic valve or system !

Unread postAuthor: chrissilvermancs » Mon Mar 16, 2009 10:54 pm

i am am here asking anyone for advice on making a real automatic valve or system. i understand a lot of air and tools...ect are needed but i have not yet seen a full auto design that if works can go lager than a BB. i have tried a blow forward system difficult and you need air pulsing so is not the same a a real full auto. if your going to tell me its hard or anything not related to the topic please don't. (personally i have always wanted a auto tennis ball gun and that what i am aiming for). right now i am looking at blow back designs but i need help. please if you have any ideas.

and yes i have seen the previous post but nothing is labeled on the diagram nor dose it move so i can not tell what are the moving parts and where the air goes ect.
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Unread postAuthor: grock » Mon Mar 16, 2009 11:21 pm

well, if you have the stuff to scale it up, you could shoot anything on automatic, but youd need one hell of a compressor to shoot anything bigger then bbs
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Unread postAuthor: i-will » Tue Mar 17, 2009 2:44 am

have u work on any semi-autos yet. if not then a full-auto's cycle will be a little more difficult to understand. also i kinda doubt that u know much about "air and tools" with that starting post and thae question it contains. but if u do understand and i'm just a jerk then try going they route i'm going. stacked tube.
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Unread postAuthor: jackssmirkingrevenge » Tue Mar 17, 2009 3:15 am

Unless you have a massive compressor, an auto tennis ball gun is going to be impractical.

I would look into the possibility of combustion cartridgesas suggested in the other thread.
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Unread postAuthor: psycix » Tue Mar 17, 2009 10:58 am

When scaling it up, you NEED a valve that will conserve air.
When the projectile leaves the barrel, usually there is still alot pressure left in the chamber. If you can get the valve to close at this time, you're all set.
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Unread postAuthor: Hubb » Tue Mar 17, 2009 11:04 am

What about clide's golf ball launcher, located on the front page?
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Unread postAuthor: POLAND_SPUD » Tue Mar 17, 2009 4:08 pm

the first question you have to ask yourself is whether you really want to spend some $$ on it or you've just asked this question out of curiosity... lol there is a topic like this every month so don't blame me for saying this

the biggest problem is air supply (and ammo supply)... either you need to have a good compressor or you have to build a gun with good performance that you could sacrifice by cut down chamber volume to reduce air consumption...

for me there are two ways of building a gun like this, which in turn have two variants as far as the bolt is concerned... first of all you can either

+use two solenoid sprinkler valves and a timing circut that would handle filling and firing sequence at adjustable intervals (this is probably the best option if you live in the US an you don't want to build a piston valve)

+use a piston valve combined with a solenoid 3 way valve... this still needs a timing circut but this time you have to control only one valve

now as far as bolts are concerned you can either use:
-a blowforward bolt (but that would lower performance quite a bit and requires some work)

-use an air ram connected to the chamber design (lol why no one has invented a name for it yet?? ok so from now on it's called an airram bolt :D) (search 'I has semi auto' or 'FANG' if you want to get the idea of what it is)

-find a different method
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Unread postAuthor: biged » Tue Mar 17, 2009 6:56 pm

You will need a high volume of air CFM (Cubic Feet Minute). I use a towed Diesel Atlas compressor which can supply 120-130 CFM at bar 10 (150 psi), via 1 inch hose and crows feet couplings. Relief valve is set to bar 12.

I have a dead 90 lbs jack hammer which is undergoing a transformation for a big auto-cannon. Also patiently waiting for a 10" barrel for a bowling ball cannon.

///ed///
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Unread postAuthor: chrissilvermancs » Tue Mar 17, 2009 9:25 pm

to be honest i was hoping for some designs i know i spent 2 mins writing the post and i thought some people here could use some common scense and realize that by "air and tools" i meant that i understand that it will use a lot of air pershot and needs a lot of air to keep it going. that everyone here thinks its almost impractical because no one has seen it done and the amount of air needed.

and by tools i know that lathes and some metal shop parts might be needed. but to be criticized on my post and told that i will need a high volume of cfm. which is kinda why i asked people not to post things like that but next time i will put "if your trying earn more spud bucks or get your name on every post don't post here".

and to the ligament question, yes i have built a semi auto i made a really small metal blow forward gun to test the principal.

i have been working on a modified blow back/forward disign if you want i can post it my drawing skills are pritty crude though and i don't know how to do the jif moving art thing.

but thank you Poland_spud for saying something related to the topic
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Last edited by chrissilvermancs on Tue Mar 17, 2009 10:33 pm, edited 1 time in total.
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Unread postAuthor: Ragnarok » Tue Mar 17, 2009 9:49 pm

POLAND_SPUD wrote:lol why no one has invented a name for it yet?? ok so from now on it's called an airram bolt

Actually, I put gave a name to the system almost a year ago, here - the Jackhammer system, as the idea reminded me of the operation of reciprocating pneumatic drills.
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Re: a real automatic valve or system !

Unread postAuthor: jackssmirkingrevenge » Wed Mar 18, 2009 12:55 am

chrissilvermancs wrote:i have not yet seen a full auto design that if works can go larger than a BB.


Scale this up then ;)

edit: html
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Last edited by jackssmirkingrevenge on Wed Mar 18, 2009 2:38 am, edited 1 time in total.
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Unread postAuthor: frankrede » Wed Mar 18, 2009 2:12 am

chrissilvermancs wrote:to be honest i was hoping for some designs i know i spent 2 mins writing the post and i thought some people here could use some common scense and realize that by "air and tools" i meant that i understand that it will use a lot of air pershot and needs a lot of air to keep it going. that everyone here thinks its almost impractical because no one has seen it done and the amount of air needed.

and by tools i know that lathes and some metal shop parts might be needed. but to be criticized on my post and told that i will need a high volume of cfm. which is kinda why i asked people not to post things like that but next time i will put "if your trying earn more spud bucks or get your name on every post don't post here".

and to the ligament question, yes i have built a semi auto i made a really small metal blow forward gun to test the principal.

i have been working on a modified blow back/forward disign if you want i can post it my drawing skills are pritty crude though and i don't know how to do the jif moving art thing.

but thank you Poland_spud for saying something related to the topic
Some of the more senior members of this website replied to your answer...and you accuse them of doing it to accrue spudbux?Wow...
If you are so much better than all of us who lack common sense then why do I see you BEGGING for plans? Call them designs, schematics or whatever, it's still a plan.
Go figure something out on your own, if you understand it so well then why don't go make your own.
These people are trying to help you by telling you why they don't work.
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Unread postAuthor: inonickname » Wed Mar 18, 2009 4:34 am

I'd drop this rubbish you've come up with, otherwise you'll end up even more boycotted than rastamuffin. Not a great place to be.

You state you need a "high volume of cfm". Unless I'm mistaken, CFM is an acronym for 'cubic feet/minute'. The most common place for this term would be for how much air a fan could me in a minute- unless you mean how many cubic feet your compressor can pump in a minute; but that would hardly make sense in the context.

For animating .Gif images I'd recommend downloading a free trial of something such as Ulead GIF animator 5. Just make your images (frames) in paint, then import and arrange them there. You can also find helpful guides on animation around the web.

In a full automatic (as tests have shown) a blow forward bolt should be used in conjunction with a valve that can supply a pulsed air source- without it the bolt will either not cycle at all or cycle so insanely fast that you will not be able to feed ammunition in fast enough.

As for valves- there are three very good sources here. For a start you could look over JSR's designs- if you were ambitious many of them could be upscaled. Other places to be looked in would be the showcase and the theories/accessories database.

You could adapt existing valves- like the examples of piloting a QEV with a pop-off, using a 555 circuit to pilot a solenoid..et cetera.

You've been given good help, pull your head in.
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Unread postAuthor: chrissilvermancs » Wed Mar 18, 2009 11:56 pm

first thanks for the info on the gif

and seconed im not saying im better than anyone here i just find it dumb that people are posting that i need a varry powerfull air compressor and i already mention that i understand this in the post.

third i did not say that i would need a high volume of cfm i simply quoted the person who said priviously, wich i mentioned.
but to be criticized on my post and told that i will need a high volume of cfm

from
biged wrote:You will need a high volume of air CFM (Cubic Feet Minute). I use a towed Diesel Atlas compressor which can supply 120-130 CFM at bar 10 (150 psi), via 1 inch hose and crows feet couplings. Relief valve is set to bar 12.

I have a dead 90 lbs jack hammer which is undergoing a transformation for a big auto-cannon. Also patiently waiting for a 10" barrel for a bowling ball cannon.

///ed///


but this really dose not matter

but yes i have been looking around and i was thinking of doing a strait vision of the GB semi but attaching a pole that would connect from the back piston to the blow foreword one. this way springs are not needed and everything operated of air. and changing the dimensions so this could work. but i didn't want to post an idea that that im not sure on but here it is
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Unread postAuthor: mark.f » Thu Mar 19, 2009 12:15 am

A better example than my work

The above example could be easily modified to full auto by using a pop-off valve for a pilot valve.

The cannon jack posted (images are dead) simply uses a Q.E.V. with a pop-off pilot, and an air source. I used a 90 PSI pop-off to reduce air consumption, but it really depends on what type of compressor you have.

The ROF is controlled most effectively with this design by the flow of air into the cannon, so your trigger valve (NOT pilot valve, the fill valve) should be chosen carefully. A flow regulator could be added as well.

As to the ammo feeding, the paddle system linked in this and jack's post or a simple blow-forward bolt will work. The reason you haven't seen "a single auto design shooting larger than a BB work" is simply because you haven't looked hard enough. GalFisk made one that shot airsoft pellets. :)

Also, if you're referring to BB machine guns in your first post, have a look in the wiki at "Vogt Pattern" guns. DR made one that shot tennis balls, and another one that shot golf balls.

EDIT: here's another example of the "paddle" system. This is the one built by DR (BewareOfDog) that shoots golfballs. Again, a simple sprinkler pilot will allow this cannon to fire full-auto, but in this case you'd be going for as much fill-flow as possible... air consumption is pretty heavy.

Video of DR's S.A. GB Gun
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