Semi- or Full-Automatic Water Balloon Launcher

[Silence]

In planning for a tentative Star Wars Battlefront II mod involving soaker battles, I reminded myself of wetmonkey442's concept sponge bullet rifle. However, I think such a design would be more practical with small water balloons (perhaps 1" or whatever is the smallest possible) as opposed to sponge bullets. Water balloons have been proved to be functional when shot from water balloon launchers, as opposed to sponges which could "leak" water, possibly not be as aerodynamic, and which would not carry as much water or release it quickly enough upon impact. Of course, the sponge bullet idea is still excellent--it's just that water balloons have been reliably tested.

I've discovered that those black canisters that held now-outdated camera film rolls would be ideal sabots for 1.25" barrels (but with ~1" balloons inside to prevent them from sticking)--with the caps removed, of course. If a cartridge-style system is used, many of these shells could be prepared in advance, with the caps on top to keep the balloons inside. Also, the fairly cylindrical shape (except for the rim when the cap goes) keeps the shell stable. Such a design would be fairly simple and hopefully effective too.

I am leaning from the plunger-type style used in many Nerf homemades, as that just involves excessive complexity--although there wouldn't be a need for more sabots which would be flying everywhere, and also because it would waste as much air. While the Nerf designs out there can be easily modified to fire small water balloons, this method will have to wait even longer than the sabot method.

While heavy, an air tank and a regulator on the gun would be convenient, as you would be able to reduce the pressure to make the ordnance "safe" from direct hits at closer range--and as with pretty much any relatively light thing, at maximum range, air resistance will make them safe.

EDIT @ 7:39: For some reason, I can't get the title to read "WBL" instead of "water balloon launcher." Is this some type of filter?

[DX]

The filter will automatically spit out water balloon launcher. I don't complain about the word filter as much anymore since it is mainly used for turning useless acronyms into useful SEO keywords. Usually.

I like the idea of using some kind of semi-auto system to shoot small balloons or something that can deliver water in a more bullet-like way. However, I hate shells, since then you are not just shooting water at someone. With sabots fired at safe range, the sabot falls before it reaches anyone.

While it might take a while to build a semi/full auto gun in this manner, the idea could be tested immediately. Take a water cannon or water balloon launcher, unscrew the current barrel, and screw on the appropriate-sized new barrel.

[Silence]

Actually, I just remembered that the actual IDs of PVC are a bit larger than what the name implies. So in others words, what I thought would have been a great sabot actually would have a bit of extra space between its rim and the bore. Of course, it would still be relatively effective; and the caps to these containers might make perfect seals after all. Perhaps you could cut off the bottom and glue the cap on top...

I suppose I just made yet another of my terminology errors; I said "shell" instead of "sabot." You're right, the idea of shooting solid objects at somebody in a water war probably wouldn't seem very appreciated. I just can't think of the right word, though (perhaps it is "round")...

Originally Posted by Duxburian

While it might take a while to build a semi/full auto gun in this manner, the idea could be tested immediately. Take a water cannon or water balloon launcher, unscrew the current barrel, and screw on the appropriate-sized new barrel.

I like the way you phrase it. Because pretty much all of the technology used in such a design will have been tested to death before, it's fairly reliable. The main difference involves the way you'd use such a weapon; instead of having a long-range and more artillery-like weapon, you have something that would be used more like a rifle. I suppose it would pretty much be used as a sort of sniper rifle, as its primary purpose would be to get an edge in range over conventional soakers. Of course, a bit of splash damage is never bad.

The sabot version I spoke of above is actually incredibly simple. It's pretty much just a small-bore WBL but with a hole cut out of part of the back of the barrel. Either a bottom-mounted spring-fed magazine or a top-mounted gravity-fed magazine would feed the sabots/cartridges into the barrel, with a slight incline so that the one inside the barrel is in front of the ones in the magazines to prevent it being caught. However, the performance problem with the design is that it would be inefficient, mainly for full-automatic fire; an incredible amount of air would escape in between water balloons, unless the barrel was long enough and/or the magazine spring was strong enough to push in the next round right after the previous one was fired.

As I said above, the other problems would include the need of a ton of film containers (that you can't really get anymore) and hopefully for a regulator for the small on-board air tank.

Heh, that word filter could actually come in handy...we currently resort to abbreviations in order to make sure we don't have to type out the entire term all the time, so why was I getting angry at it for messing up my title? All it's doing is saving me the same amount of hassle, but with more readability to people not familiar with the abbreviation. Indeed, it is quite a convenience!

[Drenchenator]

I can see a real way of building a semi-automatic or fully automatic water balloon launcher. To tell the truth, I have technically build half of the gun (though it would need to be made more powerful, the chamber size was chosen to shoot Nerf darts and not full water balloons). The second half would be a bolt-action barrel assembly.

The gun uses a homemade semi-automatic piston valve to allow only the air in pressure chamber to be released (keeping the air in the pressure "reservior"). All that it needs right now to become "semi-automatic" is a the right barrell assembly. For more information on how the valves and trigger system in my gun work, check out this post at NerfHaven on the subject.

The easiest buildable semi-automatic barrel assembly that I can see possible from piping would be a gas system. Excess air after the shot is channeled into a piston which pushes the bolt back and reloads the barrel. All that the piston would need to be is a "reverse" pump.

The main difference involves the way you'd use such a weapon; instead of having a long-range and more artillery-like weapon, you have something that would be used more like a rifle.

Actually, there should be no reason to sacrifice range for rate of fire. I build my Nerf homemade to have both of those qualities, so there is no reason that the same concepts can't be applied to water balloon launchers. The only redeeming quality I see in water balloon launchers are their range.

All of the technology is there, someone should just build a real "rapid-fire" water balloon launcher already.

[Silence]

Thanks for the reply. While I've read up quite a bit on your Nerf homemade, that trigger system diagram really helps--at least for semi-automatic fire.

Actually, I have seen and read that machine gun article at HowStuffWorks, and I was going to refer to the gas system of reloading. But the dilemma is that if one was to build an automatic plunger WBL, it would have to be very efficient (actually, that wouldn't be too hard at slow firing speeds relative to machine guns) both to conserve air and, more importantly, to enable the plunger to function properly. In machine guns, the piston doesn't really have to move that quickly because the firing force comes from combustion; but in a WBL, it must actually be moving fast enough to transfer sufficient force to the water balloon.

Perhaps I could do something radical here...given that smaller water balloons won't pop as easily, you could grease the bore and then stuff in a balloon to create a decent seal. Assuming the balloon won't pop and that it will be shot efficiently, I'm sure there would be more design flexibility.

I never said this will sacrifice range...I was just pointing out that one of the reasons some people like WBLs are because of their relatively incredible range. So as you say, the technology for something like this is out there, ready to be used. It's just that I don't like how you have to use standard WBLs as if they are artillery (and they are pretty ineffective since you don't have many [if any] targets actually suitable for artillery). I'd rather be able to use the range in a rifle-like weapon, and that's pretty much why I liked wetmonkey442's concept for a long range sponge bullet weapon.

Your Nerf homemade would be superb for shooting small water balloons, and I like the efficient PC system. While it wouldn't really work for automatic fire (at least, not with a bunch of major changes), pretty much everything is there for semi-auto, as you said. Some day, I'd like to try the inefficient system I suggested in which rounds are pretty much just jammed into a jet of air, and if others like the idea of a greased barrel for small water balloons without a sabot, I would also like to try a full-automatic system.

[Drenchenator]

While it wouldn't really work for automatic fire (at least, not with a bunch of major changes), pretty much everything is there for semi-auto, as you said.

To get fully automatic fire on my gun, only one change would be needed. Since the trigger system is independent of the proposed barrel assembly, all that you need to do is somehow make the piston reciprocate. This can be done by using a small electric motor, a push button, a small gear, a large gear, and a small wheel. Using this system, you can easily get fully automatic fire as long as compressed air can be supplied (as well as electricity for the motor).

I have been trying to think of a way to create fully automatic fire by only using air, but so far I have though of nothing. But semi-auto (if attainable) isn't bad at all.

Actually, I have seen and read that machine gun article at HowStuffWorks, and I was going to refer to the gas system of reloading. But the dilemma is that if one was to build an automatic plunger water balloon launcher, it would have to be very efficient (actually, that wouldn't be too hard at slow firing speeds relative to machine guns) both to conserve air and, more importantly, to enable the plunger to function properly. In machine guns, the piston doesn't really have to move that quickly because the firing force comes from combustion; but in a water balloon launcher, it must actually be moving fast enough to transfer sufficient force to the water balloon.

Are you talking about a spring plunger water balloon launcher? The gas system would work excellently with a pneumatic (air pressure) launcher. I would not be too worried about wasted air, either some air is wasted or the projectile does not leave the barrel. Efficiency would be more or less how well it can handle the drop in pressure from its operation. This can be fixed with a regulator though. You wouldn't need to worry about wasted air if the system can sustain itself well.

[Silence]

Well then, the design I suggested would work quite well. A long barrel and strong springs in the magazine would work well enough, and I was only worried about wasted air (so it's not actually inefficiency after all; thanks for excusing the poor terminology) because it's firing even when nothing is in the barrel. The long barrel and springs should make sure that all the air is used to propel the sabots as much as possible.

I'm sure I can find some new type of sabot that is much more plentiful, too. There's no need to worry about that until something like this actually gets built.

How large are the smallest regulators? I'm considering using a very small air tank and a small regulator so that they can be left on the actual gun itself, thus providing enough air to actually fire the many rounds that I'd imagine would be used. This WBL is incredibly simple, so if I ever decide to build WBLs in addition to homemades, I might try it.

[m15399]

I'm worried about the size of water balloon you intend to use. How are you going to get water balloons weak enough to break at such a small size? Perhaps you should just make a gigantic pneumatic clip fed 3" water balloon monstrosity...

[Silence]

Well, I don't really plan on using the large (4", I believe) water balloons unless I have to. I think I've seen small balloons around the house, but then again they weren't inflated so I don't know their exact size. At any rate, if it turns out that 4" water balloons are the only option, then I'll "weaken" the balloons in the method sometimes recommended to detonate in midair. However, I'm sure I can find smaller balloons eventually, though they probably won't be intended for water fights.

Good point, though.

[Lt.Winters]

Small water balloons? Casings? Sounds like something I thought of weeks ago. Hopefully yours will reach the building stage.

[13lack-ace]

Ok, this is my division!!!

But one small problem... Do you know what is would look like, i have shotty models, mortars, heavy arlilary, Manned machine gun, Mounted machine guns, etc

So simlpy tell me what model you want or what model you need and ill draw up some blue prints.




13lack-Ace

[Silence]

Somewhat what I'm thinking about.

rounded rectangle--short, rectangular metal PC for high pressures
vertical rectangle--large magazine, slightly pointed to one side for ease of reloading and for extra space
weird complex pieces--regulator, since you want all your shots to hit the same general area
circle--modified solenoid sprinkler valve, with a trigger that goes on the vertical handle part

[joannaardway]

A regulator doesn't have enough flow to use like that. (assuming I am correct in seeing it the way you think it should be)

You need to fill your chamber with the regulator, then fire through a high flow valve (which a sprinkler valve is fine for)

I think that that design might need some more work. I'll bring along some of my full auto/semi auto designs with pictures tommorrow.

[Silence]

So you're saying that there should be another chamber that the regulator fills? If so, then that would most likely be suitable for semi-automatic fire. I assumed a regulator would provide sufficient airflow, since it evidently worked on SuperCAP. Then again, this is just releasing the air into the open.

[joannaardway]

Your main "firing chamber" is filled via a regulator from a higher pressure larger tank (or CO2 bottle, etc.)

Your main valve then leads off this main chamber, and leads to the barrel.

Water has a much lower flow than air. A typical peak flow through a trigger sprinkler valve is in the region of 200 Normal (1 atm equivalent) litres per second. A powerful laucher could break the 350 Nl/s mark.

An average flow for a powerful launcher is in the region of 150 Nl/s, so your launcher might be in the 80-100 Nl/s range.

A regulator can normally only manage about 10-15 Nl/s - nowhere near the required figure (and it will slaughter performance) - More than enough to manage flow for a CAP though.

At 60 psi, 15 Nl/s could provide for an output of 3 or 4 litres of water a second - it would limit a muzzle velocity to only 20 or 30 m/s, on a good day with a 5 foot barrel or so.

If your chamber is filled to a certain pressure, then muzzle velocities will be consistent-ish. Water balloon weight variance will affect things more.

I'm sorry, I haven't got time to post any of the plans I've got, but I'll get them sorted soon.