Cartridge help.

Harness the power of precision mixtures of pressurized flammable vapor. Safety first! These are advanced potato guns - not for the beginner.
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Fnord
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Thu Oct 20, 2011 7:42 pm

Sorry, a half mile is not happening. Not even 1,000 feet.
Paintballs have a huge amount of drag vs. density, and that means they loose velocity quickly.
If it's even possible it'll be incredibly unsafe, because over such distances you'll have a very narrow 'Goldilocks zone';
By that I mean the distance where a paintball is traveling fast enough to break on impact, yet still slow enough to avoid causing injury.
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warhead052
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Thu Oct 20, 2011 7:46 pm

Fnord, I am going to machine sabots that fit in the barrel perfectly and break away about 3/4 of the way through the flight.
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Thu Oct 20, 2011 7:52 pm

evanmcorleytv wrote:
warhead052 wrote:Evan, I have already made a hybrid cartridge (yeah I know its made out of pvc and not the safest, but I still did it...) and I have a pretty big knowledge of pneumatic's now as well. Put it this way, this sort of stuff comes as second nature to me even though no one in the family 'cept my grandfather is really into mechanical things and the like.
Same with me.. I'm the only one who knows how to repair small engines, and even large engines, and I build advanced RC planes from SCRATCH, and I have had some machining experience, not much though, and I also have MULTIPLE designs for that semi automatic airsoft sniper rifle that shoots (around) 500 FPS which I hope to finish soon.. just saying, you're not the only young inventor around..
With all the info on this site, I think with the right resources warhead can pull this off. Age has nothing to do with this hobby, so stop making it an issue.

Now, warhead... I think a good design for the cartridges would be to use a co-axial piston on each. Instead of the complicated newer hybrid valve designs, you should just get a hefty spring to keep the piston seated
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Thu Oct 20, 2011 7:57 pm

Ramses, that was what I'd suggested. Warhead, not to burst your bubble, but designing sabots like that isn't an easy task. There would have to be a timed release, and that would increase the cost per shot dramatically.

If you wanted airburst I'd suggest some <b>very</b> reliable fuse, and a [the rules] burst charge, akin to a fireworks shell and stars. But the danger of a misfire and having it go off near players is too great in my opinion.
/sarcasm, /hyperbole
warhead052
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Thu Oct 20, 2011 8:30 pm

Locked, that's exactly what my initial plan was. I may have to experiment with some 2x mix's and some pipe that I have around my house.

Zeus, I think that I need to get the initial firing mechanism done before I think about ammo, so its not a huge deal right now.
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Thu Oct 20, 2011 8:48 pm

warhead052 wrote:Zeus, I think that I need to get the initial firing mechanism done before I think about ammo, so its not a huge deal right now.
Well it is a big deal if you're not going to be able to meet the performance requirements :wink:

Personally, I don't see paintballs being launched a mile in a sabot that discards 3/4 way through the flight. Even if it were possible, it would probably be a bit dangerous as the sabot would have to be quite dense and reasonably aerodynamic to travel that distance.

Good to see you taking on the challenge though, especially since it's a hybrid. Would be awesome if you managed to get the shell cartridges working, perhaps your friends will forget about how far it needs to shoot when they see it in action.
warhead052
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Thu Oct 20, 2011 8:58 pm

Yeah, well another reason is my paycheck at the end of it. 14 and getting close to $800 for a working product. :D I am so pumped up!
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Thu Oct 20, 2011 9:40 pm

evanmcorleytv wrote:Hey, I thought I would draw you a picture of the diagram.. It's done now, just let me upload it..

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DONE!! Hope this helps with the loading system!!
How exactly does it work? Yeah, sorry for double post...
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Thu Oct 20, 2011 11:04 pm

Cartridge hybrid, sure. Half a mile with paintballs, incredbly unlikely. As others have stated paintballs have a large amount of drag, and even if you do manage to get that distance, i highly doubt youd hit anything but ground, if any of the paintballs even made it that distance. I see that you want realism, but in turn your not being realistic with this project.
Yeah, it's that important.
warhead052
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Fri Oct 21, 2011 10:35 am

What about some sort of paint grenade? I think I should focus more on the mechanics of this first though, and then figure out the ammo.
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Fri Oct 21, 2011 10:53 am

warhead052 wrote:Yeah, well another reason is my paycheck at the end of it. 14 and getting close to $800 for a working product. :D I am so pumped up!
Damn kid, 800 bucks is a hefty profit! I hope you pull it off, 800 bucks for a 14 year old to go have fun with is some serious motivation!! Good luck pal!! 8) 8)
Go Bruins!!!!
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DYI
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Fri Oct 21, 2011 11:46 am

Warhead, as much as I hate to sound like I actually gained anything from my design courses last year, your employers really need to give you VASTLY more information on what exactly they're trying to achieve with this before you can even start considering a design. It's clear that this project is currently all over the place, and projects like that never get off the ground.

You need to know what they're trying to do. What range are they looking for? What terminal effects? Are they shooting line-of-sight, over obstacles, in through the tops of bunkers? What are the rules of the fields they'll be using this design at? If the players aren't wearing PPE considerably more extensive than traditional paintball or airsoft gear, don't even think about those timed release rounds you mentioned above - people don't generally like having large chunks of sabot or casing dropped on their heads / flying at their faces.

If you're trying to deliver a payload 1.5 miles out, it will be difficult to come up with a design which will not drop relatively heavy fragments on the field. The best I can think of is a very thin walled plastic tube which is loaded to about 1g/cc with payload (and liquid to fill the gaps, if the payload is airsoft rounds). This way it's essentially all payload, and the skin doesn't have enough momentum to injure anyone after it's pealed open to release the payload (likely using [magic] to achieve the skin separation). For example, a 1.5" round 24" long (I'm assuming fins for stabilization here, so the bore of the launcher would be something like 3") would mass around 700g and at 200m/s muzzle speed, have a maximum range of ~1.5 miles.

I achieved performance very similar to that with the SCTBDC running 400psi and a 3" bore. This particular launcher had an overall length of 17', although that could be shortened to about 13' with some extra money. If your clients don't want a tremendously unwieldy launcher, I'd suggest a hybrid.

Also note that if one of these fails to burst as planned and manages to hit someone in the general torso or head region, he is quite likely going to end up dead. Even if that was a typo and you only need a half mile range, an unseparated projectile hitting someone could still be lethal, regardless of the projectile's low structural integrity.

In response to your latest post: you can't responsibly design a launcher platform for someone without knowing what needs to be fired. Figure out your projectile first, build a gun around that.
Last edited by DYI on Fri Oct 21, 2011 4:46 pm, edited 2 times in total.
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warhead052
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Fri Oct 21, 2011 12:30 pm

Well then, what would be the furthest distances for a toilet paper sabot of paintballs or bb's be?
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Fri Oct 21, 2011 2:12 pm

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evanmcorleytv
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Fri Oct 21, 2011 4:07 pm

DYI wrote:Warhead, as much as I hate to sound like I actually gained anything from my design courses last year, your employers really need to give you VASTLY more information on what exactly they're trying to achieve with this before you can even start considering a design. It's clear that this project is currently all over the place, and projects like that never get off the ground.

You need to know what they're trying to do. What range are they looking for? What terminal effects? Are they shooting line-of-sight, over obstacles, in through the tops of bunkers? What are the rules of the fields they'll be using this design at? If the players aren't wearing PPE considerably more extensive than traditional paintball or airsoft gear, don't even think about those timed release rounds you mentioned above - people don't generally like having large chunks of sabot or casing dropped on their heads / flying at their faces.

If you're trying to deliver a payload 1.5 miles out, it will be difficult to come up with a design which will not drop relatively heavy fragments on the field. The best I can think of is a very thin walled plastic tube which is loaded to about 1g/cc with payload (and liquid to fill the gaps, if the payload is airsoft rounds). This way it's essentially all payload, and the skin doesn't have enough momentum to injure anyone after it's pealed open to release the payload (likely using [magic] to achieve the skin separation). For example, a 1.5" round 24" long (I'm assuming fins for stabilization here, so the bore of the launcher would be something like 3") would mass around 700g and at 200m/s muzzle speed, and have a maximum range of ~1.5 miles.

I achieved performance very similar to that with the SCTBDC running 400psi and a 3" bore. This particular launcher had an overall length of 17', although that could be shortened to about 13' with some extra money. If your clients don't want a tremendously unwieldy launcher, I'd suggest a hybrid.

Also note that if one of these fails to burst as planned and manages to hit something in the general torso or head region, he is quite likely going to end up dead. Even if that was a typo and you only need a half mile range, an unseparated projectile hitting someone could still be lethal, regardless of the projectile's low structural integrity.

In response to your latest post: you can't responsibly design a launcher platform for someone without knowing what needs to be fired. Figure out your projectile first, build a gun around that.
That's exactly what I was thinking.. I have played airsoft with a bazooka that I made, and running at 50 PSI, it gave me a deep purple bruise about 5-6 inches in diameter, and I almost had to go to the hospital.. That thing already had a range of about 300 yards at 150 PSI.. So, I would find out what they want/need, and then you MUST tell them the risks, because then you wouldn't be held legally accountable..
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