inline vortex bbsmg

[Mr.michael.2468]

hello spudfiles, just happened upon these great little pieces of engineering wonder called "vortex blocks" i simply fell in love with the simplicity of the design and decieded to make this my next project after my rocket launcher which works wonderfully

but i have a couple questions about these inline vortex bbsmgs, i think its great that people have achieved such high rpm out of them but id really like to dial this back to like maybe a 1000rpm, that would save me big time on money for ammo,

also im wondering if the same block and set up with a different barrel will work like can i use the the same gun with a barrel for metal bbs then replace the barrel and shoot airtsoft bbs out of it?

and links to guys that have already done this would also be much appreciated, from the research i've done and with my handiness with pvc pipe and air pressure i'll be fine on the build,

also for air supplies, i was thinking a pvc backpack set up with a high pressure hose running through a blow valve would work fine, but im also wondering about co2 tanks as im a paintballer and have a few laying around im wondering which will work better and be better for the money, because i know that co2 regulators can get kinda pricey,

any input would be great, thanks again for putting up with the noob

[Mr.michael.2468]

the above pic is my first attempt to add a photo that went succesfully and also is my first idea to reduce the rpm of the gun, would this actually help? it seems to me that decreasing the volume of the loading chamber would decrease rpm, maybe lol

[Gun Freak]

I think that if making the chamber smaller would do anything it would be raise the rof because pressure would build up quicker between each shot...

[Mr.michael.2468]

hmmmm really? is there any design aspect other than this that'll slow down the rof? and are you talking about the hole in the vortex block specifically or the chamber as a whole? is it something that you've experimented with for optimization, and i could just do the opposite?

[3VIL G3NIUS]

I'd suggest a 3/4 to 1" hole for the vortex. You can try smaller if you want but I think a detent would slow the rate of fire much more efficiently, and give you more power.

[saefroch]

I think a detent will slow down ROF, especially if the popping pressure of the detent is close to the pressure of your air source. If you go that route, you could use a smaller valve orifice on the input to the vortex block. Those two changes would slow up ROF, but hopefully not just having you spraying air...

[Gun Freak]

If you go the detent route, I wouldn't use a vortex block, I would just do a cloud.

[Mr.michael.2468]

well i'd like to keep it a vortex, and what is the detent? im not familiar with the term, also some said something about restricting the air flow, thats seems the most simple to me, any other input?

[Mr.michael.2468]

and one other question, what's a good spring to use for the plunger? have left over airsoft springs but those seem to powerful compared to the ones i've seen use

[Gun Freak]

Try to find a weaker one... Too strong a spring will jam the vortex block.

A detent is something you put in or before the barrel that creates an airtight seal with the bb so that more pressure needs to build up to force it past the detent making a more powerful shot. A detent also lowers the rof because it takes longer in between shots to build up enough pressure. They aren't commonly used with vortexes though... A vortex I think would feed it too quickly.

[cammyd32]

A vortex I think would feed it too quickly.

and consequently jam the gun. the problem with vortexes is that there are not many mays to stem the rof from the naturally high one that they are built with.
Your idea of a small air inlet would work, but only with a detent in the barrel otherwise you will lose a lot of power in the lack of a decent air flow.
my other thoughts on your design are that the if the air inlet is small (depending completely on how big your inlet is) then it may not give the bbs enough inertia to cycle round the block, and as of that at the lower pressures you will get when you are running out of air the bbs will not fire and all you will get is a faint hissing sound.

If you decide to change to a cloud there is a person who did a very good job on reducing the rof using a detent see here: http://www.spudfiles.com/forums/viewtop ... 260#320260
hope this helps

[Mr.michael.2468]

hmmm well i think i'll just deal with the high rate of fire lol, but i made a super ghetto model with duct tape end caps and a wooden block with cardboard shield over the the hole, used a one inch hole and i just stuck a 3/8in brass nipple fitting into the bottom and drilled a hole just big enough for airsoft bbs which were the first things i saw laying around to shoot i got one good burst out of at 20psi with an ultra ghetto 2- 2liter bottle back pack air tank shot at least 100 bbs in like 4 seconds lol, couldnt get it to work after that, i think it blew to duct tape away from the vortex block and then the air just escaped out the hole in the duct tape, not through the vortex block, any way i'll try to post a pic above, but how do you post pics in like a comment?

[Gun Freak]

You can upload them to the site where it says add attachment or you can upload them to a website like photobucket or image shack.

[Mr.michael.2468]

hey alrite got parts to actually make the thing, didn't even need to glue it, im still using a wooden vortex block, i tried working with acrylic (now my least favorite stuff to work with) but gave up cuz it just cracks, i bought an air compressor too, finally

i've been having fun with that but i just put my little ghetto version together with a pen body as a barrel and the old spring that was too strong, it worked... well it just worked it would spray short bursts maybe 2 seconds long then i'd have to shake it too feed more, wondering what the problem is, is it a crappy vortex block? or is it just my spring that doesn't really work quite right?

im running the thing at 105psi for like 2 seconds because my compressor only has a 1 gal tank on it (getting 5 gal for it soon) but at that pressure with a pen body thats like 6inches long the bbs go pretty darn fast and at 75psi-ish it put some pretty nasty dents in a pop can from like 35ft away,

any help with little things you guys have figured out after working with these things would be great to know lol

[Gun Freak]

A weaker spring would probably help with the feeding. Also, typically, less ghetto=better working gun lol so yeah a good vortex block might also help.