Super Soaker Central

I never intended to show this gun to the community, as I don't think it really counts as a WBL. Yes, it can launch them however I designed this thing to have maximum power, not to shoot water balloons. I first built this thing about half a year ago with some extra money that I wanted to burn.

First off, it uses the Mauler Valve. For those who don't know, this is basically the most powerful spud gun valve money can buy. Compared to a modded sprinkler valve, it opens faster and has about 10 times as much flow. This is because in addition to having a 2" opening, the flow is completely unrestricted unlike sprinkler valves. The cost for the whole gun all up was around $300. This may seem ridiculous, and I suppose it is. However when you consider the cost of a paint ball gun, and to me this is way cooler than a paint ball gun, I think it's justified.

Here's a pic of it. Chamber is 3"x24", and the barrel is 2.5"x30". If anyone wants any videos, give me some ideas and I'll see what I can do.



Anyway, I was outside shooting water bombs, and noticed something. I was keeping the pressure low to prevent popping the balloon, yet however no matter what I tried, I couldn't shoot a water bomb anywhere close to the same distance that my ball valve pneumatic could without popping them. This got me thinking. Despite being far more powerful, couldn't you just lower the pressure and get the same performance? Why were they breaking anyway? I had often thought how neat it would be to make a tiny, but high performance WBL with a Mauler Valve. Then I finally realized why this wouldn't work. I'll explain this below.

Let's assume that you have 2 different WBL's. Gun A and Gun B. For the purpose of the explanation, both guns have the same muzzle velocity which should translate into both having the same range.
Gun A is a regular ball valve pneumatic, like the Douchenator.
Gun B is a Mauler Valve pneumatic, a much smaller high efficiency design like what I have described above.

Automatically, you'd think "The Mauler Valve gun is better". It'd be far faster to pressurize, and have a smaller barrel so it would be much easier to carry, yet wouldn't sacrifice any performance. I was reading some of last year's discussions about "battle practical WBL's" from the Water Warfare Forums a few days ago, and this was one of the points brought up. A higher efficiency valve would make a better WBL. However, there is one problem that I believe no-one has factored in: Acceleration.

Now looking back at Gun A and Gun B, we can easily see that Gun B is going to subject the balloon to a lot more acceleration than Gun A. This is how it achieves the same muzzle velocity despite the smaller barrel and chamber. Now what is the one thing that kills water balloons shot from a WBL? Force from acceleration.

As you can see, Gun A has a relatively gentle acceleration spike because the valve opens slowly. Peak acceleration is around 200G's.



Because the Mauler Valve opens so fast and puts through so much air, there is a huge acceleration spike at the beginning of the shot which pops the balloon. Note in the picture below, that the peak acceleration for Gun B is over 10 times as much as Gun A! Yet, the muzzle velocity is identical. This is what destroys the balloons.



So unfortunately from this we can see that WBL's not only have limits in power, but they also have limits in efficiency as well. The super compact, high efficiency WBL is simply not possible. Anything more efficient than a sprinkler valve probably wouldn't work. Thoughts?

Edit: Clarified last paragraph
Edit 2: Added GGDT outputs

Wow, I understand completely. A better valve would subject the projectile--a water balloon in this case--to greater forces or accelerations. But water balloons pop when subjected to high forces and what not; so there must be a threshold force that would pop the balloon, and a better valve would in fact be more able to do that. It makes perfect sense now that I think about it. Good finding.

You make a good point that no one has considered before. There will be some limit to performance, and I suppose you've passed it in your super-efficient launcher. I always recommended lower pressures anyway for WBLs because the range is so high anyway that you don't need to shoot even farther. This seems to be another reason to limit pressure, as well as to use cheaper valves.

I think I should clarify some more. My point was not about high-performance launchers, but high efficiency launchers. Basically you can't have a super compact high efficiency launcher. Because of the acceleration problem, they're not possible. You're right that lower pressure would be the only solution, however having low pressure in a super compact design is going to have bad performance anyway. You'd be better off with a Douchenator.

How long is the barrel of your water balloon launcher? Low pressure in a long barrel could get high velocities with less force.

And perhaps a top-quality sabot would be able to help keep the water balloon intact. However, I haven't experimented like that, so I wouldn't know.

You've provided an insightful article that has certainly changed my ideals for WBLs. Would you mind if we put it on the site?

Having a long barrel won't help. It's the initial acceleration that does the damage. Coupling that with low pressure, you'd be lucky for the wadding and projectile to even leave the barrel. As for a sabot, I use a good-fitting lid with a piece of foam in the bottom. My foam is actually just a slice of a pool noodle.

Interesting test note: 15psi broke a 2" filled water balloon. The initial acceleration would have been quite a lot, popping the balloon. Even if it had survived, by the time it gets to the end of the barrel friction and lack of pressure has slowed it right down, which is a waste. No matter what, using a piston valve is impractical for a WBL.

As for putting it on the site, that's fine. However, I'll rewrite some bits to be more appropriate for use on the site and send it to you.

Okay, thanks.

Speaking of which, that's a rather impressive spud gun. Many spud guns don't even make use of powerful valves - they use long, unnecessary barrels or don't even pilot the valves properly. Good job!

Still, if you're interested in using water balloons with your launcher, I would try using one of WaterWolf's sabots. While the sabot obviously isn't going to make a huge difference, it could help.

You might even have luck with a custom sabot. A bowl-shaped, concave interior might do the trick by helping to spread out the force applied to the water balloon. Less pressure means a reduced chance of puncture and rupture.

Article sent.

Thanks SilentGuy. I used the GGDT a fair bit, and found that having a chamber and barrel twice as large would only give me about 20% extra performance. Considering I didn't have an air compressor at the time of building (I do now) efficiency was important. Still, it theoretically shoots golf balls at around 500fps so I'm not complaining. I say theoretically because I can't actually shoot golf balls at anything more than 50psi, as my wadding explodes if I do. According to the GGDT the golf ball is subjected to a peak acceleration of nearly 4000g's at 100psi!

As for water bombs, I have no need to shoot them apart from entertainment. I have seen WaterWolf's sabots before, and they are a very good design but I'm happy with my current setup.

Edit: Don't know why I didn't think of this before. Regular helium balloons are far more suited to this...job. I just bought a pack of 10" ones for firing and they hold up very well. A couple of videos of a balloon vs. some old plywood:
Video 1
Video 2

Please excuse the bad picture and sound quality. The "hiss-bang" noise is normal. The hiss is the pilot valve, and the bang is actual gun firing. It does sounds much better in real life, trust me.

Damage pic. As you can see the plywood is crappy and well used.

Those videos were awesome! And "well used" describes the look of the wood perfectly. The gun looked really powerful; the balloon just flew across my screen. I guess the valve really does matter that much for overall performance and efficiency.

sbell send me a revised copy of this thread for an article: http://www.sscentral.org/homemade/efficient_wbls.html

I wasn't quite sure where to put it, but it should help people looking for improved WBLs. Perhaps we should make a WBL sub-section like we have on the forum? That might be a good idea.

Thanks for the article!

Would you mind if I added the pictures you had in this thread and perhaps a couple stills from the videos? Speaking of which, vimeo really does offer top-notch video service. Congrats on the find.

I've encountered this problem as well when I was working with a modified sprinkler valve.
Good article and certainly something to consider when building my next WBL.

WaterWolf, have you tried a cup-shaped sabot? You said you've used around ten different versions, so I presume at least one of them has a cup-shape to contour to the water balloon.

Of course, that could create a suction that would effectively glue the balloon to the sabot, which is bad. And holes in the shell would let air rupture the balloon, unless the balloon is smaller than the bore and there's a rim on the sabot with air ducts in it.

Actually, I designed the Snake-Eye V7 shells, works very well.

The problem is, (as Sbell said) an issue of too much acceleration.
I have tried cup-shaped sabots in these launchers as-well and the problems you described were some of the reasons why I moved away from them.

Perhaps a shell that somehow cushioned the balloon would work in these circumstances.
I might play around with a variation of that in my Snake-Eye sabot rounds.

That's quite interesting. I would've thought that a modified 1" sprinkler valve would work, but I guess not. Didn't Falcon's latest WBL use a modded sprinkler valve? Maybe yours is more powerful than his.

I was actually planning on making a compact WBL with a modded sprinkler valve, but thanks to your findings WaterWolf, I can save myself the trouble. Considering that it'd be hard to improve on the V7 sabot, I don't see much point in trying to build one.

Looks like the best option is still the good ol' ball valve. Perhaps 3/4" sprinkler valves are a better option. I'd rather have the trigger actuation of a sprinkler valve instead of flipping a ball valve.