Water cannon numbers

Guides and discussions about building water blasters and other water warfare devices such as water balloon launchers.
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the oncoming storm
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Water cannon numbers

Postby the oncoming storm » Tue Jan 20, 2015 9:54 pm

As water Cannons get bigger they begin to become unwieldy, Here I will discuss some of the recoil forces involved in Super Cannon class weapons. For those who may not know, this can be calculated using velocity and projectile mass, velocity can be calculated using the output of a water gun if the nozzle size is also known. all theoretical blasters or unknown numbers are based on SC II's results are merely scaled. I will state that real world numbers will be slightly higher due to relativity lower friction impact as size increases from SC II.

To start the with Lets look at some numbers from the legendary Super Cannon II. Surprisingly my calculations put muzzle velocity on SC II at a mere 18 FPS on riot blast. What kind of force does that generate however ? Well using velocity and output I can estimate recoil before blaster weight (which is estimated at 20 - 25 LBS loaded) at a whopping 48lbs on Super Cannon 2's riot blast. If placed vertically and fired straight down the force would launch Super Cannon II up to a height of at least 12 feet before coming back down. No wonder Ben almost dropped it during the first riot blast test!


At current extreme a Super Cannon III was built by a fan of Super Cannon II. This beast was, 10' long, used 6" PVC tubing and needed 2 adults to hold and fire it's 2" valve riot blast nozzle, I estimate water weight alone at 200lbs. Sadly the builder sold it on ebay and never gave much in the way of numbers to SSC, but it was a beast. I estimate an effective output of 1,444 oz (11.3 gallons) per second at 100 psi (Assuming efficiency is equal). Scaling it up gives us a recoil of 85lbs. Scarier had it used a 2.5 inch valve as in Ben's CONCEPT for Super Cannon 3 it could have pushed a staggering 2,257 oz (17.6 gallons) per second at 100 psi and generate 133 lbs of recoil.

As you can see it really isn't practical to build larger cannons than Super Cannon 2 due to the shear manpower required to manhandle them during test shots.
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Re: Water cannon numbers

Postby marauder » Wed Feb 11, 2015 3:23 pm

This is a good topic. I was just thinking about how we need to really revamp homemades this year. There's so much progress being made with nerf homemade guns and in other DIY communities that should prove as inspirational to us. There's a lot of ground left to be covered in my opinion.

There will be some limitations, however, when it comes to combining power and performance. I've spent a bit of time on campus observing the giant sprinklers on the sports fields. They have insane range, probably close to 100 feet, but they also have insane output. I'm just not sure if we can push range much further than 50 feet without taking output to a level that would require much more weight. I could be wrong about this however, and it's definitely worth looking into.

FWIW, old heavy k modded CPS could definitely hit 60 feet. It was the stress and likelyhood of breaking the blasters that led people to stop doing that. So, maybe if we designed something along those lines with stronger internals we could get something really special. However, stream lamination (or turbulence rather) was definitely a concern with the old k modded guns. In community warfare we've tended to find that less turbulent streams are more effective. That might have something to do with our more open environment though. Perhaps stream turbulence wouldn't be as much of a concern if we fought in dense forest environments where wind played no factor. We only had a few k modded guns though, so I'm not the best to speculate on this issue. It's probably something Rob would have to comment on, but either way, it could lead us in the right direction with home mades.
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Re: Water cannon numbers

Postby the oncoming storm » Thu Feb 12, 2015 2:12 pm

Welcome to a nerdy thread M4 :goofy:

Anyone here got a working 60' CPS? I believe that XNeverfacedefeat's CPS 1000 Heavy K, and DX's 2100 Heavy K were the only one to ever see major use and both failed.

You have some excellent points about what we should be able to do with homemade, if I had disposable income I would be working on a modern one based on Drenchinator's Cloudbuster DR5.
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Re: Water cannon numbers

Postby DX » Fri Feb 13, 2015 1:47 am

I still have the PC from the 95 balloon 21K, but have no plans on remaking it. In all honesty, something like the 1021 is a better soaker and will last a hell of a lot longer. A heavily K-modded soaker is only viable if you can get the stream turbulence down to near-stock levels. Else, it may hit 60', but you won't be hitting anything at 60'. A soaker that can throw a laminar stream out to its max range (the way a 1021 does) enjoys more success in the type of wars we've been fighting. Despite all kinds of nozzles and experiments tried, these heavy Ks were unable to attain any kind of acceptably decent lamination.

The heavy 21Ks were good against Waterbridge because they were mainly used in ambushes and in reeds fighting. The known long range served an intimidation purpose in open shootouts, but Waterbridge tried to avoid those. You guys got a (very brief) taste of reeds fighting at Pandemonium. The faster stream velocity allows the 21K to punch through those reeds at closer ranges and hit people whose mobility is limited by the vegetation. I think I said it as early as 2004: Heavy Ks excel at close range play, not long range.

For homemades in 2015, I would not worry about the power yet. Worry about making a reliable trigger system and leakless pumps using cheap, widely available parts. Ball valves have been proven to skirmish on par with a CPS 1500, but I still prefer a trigger and mass adoption really needs triggers. Ideally, we still use ball valves for their high flow and just rig something for a puller and run a rod to it. There is an article somewhere with such a system, but it requires being able to drill a hole the same shape as a standard 3/4" brass ball valve's 1/4 turner. I don't have a bit that will make such a shape with any kind of accuracy.
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Re: Water cannon numbers

Postby marauder » Fri Feb 13, 2015 10:42 am

Would some of these parts be able to be made with a 3D printer? If so perhaps we could do some kind of joint project. A lot of times they want you to order in bulk, so we could get, maybe 5 people, to chip in for some specific parts. If not, I'd really like to look into the possibility of using a machine shop to generate some parts. Doesn't SEAL's dad do something like this? I know it'd be expensive, but ultimately it'd be worth it.
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Re: Water cannon numbers

Postby SSCBen » Fri Feb 13, 2015 4:11 pm

the oncoming storm, I'm not sure your calculations are correct. I measured the output of SCII at about 500 oz/s on riotblast (1.5 inch diameter nozzle). There's are pretty big error bars around that because it was only like two or three frames, but that was the middle of it. That works out to about 38 ft/s.

So, I calculated the recoil based on the integral momentum equation (Look this up in a fluid mechanics textbook). The equation is Recoil = Beta * rho * V^2 * A where Beta is a coefficient to account for the velocity profile (around 1.05 for SCII, I'd guess), rho is the mass density (around 1000 kg/m^3), V is the average velocity (11.5 m/s = 38 ft/s), and A is the nozzle area. This works out to about 40 pounds of force.

marauder wrote:There will be some limitations, however, when it comes to combining power and performance. I've spent a bit of time on campus observing the giant sprinklers on the sports fields. They have insane range, probably close to 100 feet, but they also have insane output. I'm just not sure if we can push range much further than 50 feet without taking output to a level that would require much more weight. I could be wrong about this however, and it's definitely worth looking into.


I've looked directly into this. My SuperCPS design gets about 58 feet effective range with an output of only about 9X (6.4 ft/X). The only other Super Soaker with a range above 45 feet and a comparable range-to-output ratio is the SS 300 (about 47 feet with an output of about 7X, so 6.7 ft/X). The SS 300 is slightly better, but I should note that the range-to-output ratio decreases considerably with range (this is what you've noticed, e.g., the XP 150 is about 17.6 ft/X), so in my opinion the SuperCPS design is superior.

And there's nothing stopping us from making better water guns in this aspect. I've been basically inactive in the online community, but lately I've been spending a fair amount of time compiling data and reading papers on these subjects. The physics are complex, but there are a lot of things we can do. It goes well beyond eliminating turbulence. We need to look at modeling and optimizing water guns, flattening the velocity profiles, eliminating cavitation, cooling down the water, controlling turbulence, eliminating swirl, eliminating unsteadiness, and some other things that don't immediately come to mind.

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Re: Water cannon numbers

Postby HBWW » Sun Feb 15, 2015 11:10 am

When I'm not knee-deep in nerf projects, I'll look to some trigger solutions, but they likely won't happen with common parts. Triggers generally need shells and structure of some sort to function. I may end up with a custom built pull valve solution for that if it's easier to get it to work than a sprung ball valve, and that seems to be the case.

It's important to not forget what we're using these things for, lol. Unfortunately, battle-practical homemades also stray off-topic for this thread.

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Re: Water cannon numbers

Postby DX » Sun Feb 15, 2015 12:47 pm

Don't worry about shells and structure...a PVC pipe suffices, with a cutout for the trigger, sheathing the trigger rod. The return spring can be held in place by epoxy putty walls. Worry about the actual trigger mechanism, we need a GOOD working model with common parts, THEN worry about making the structure more ergonomical.
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Re: Water cannon numbers

Postby SSCBen » Sun Feb 15, 2015 1:41 pm

With respect to triggers, I've been thinking about using a pneumatically actuated ball valve. Based on what my brother has done, I think a pneumatically actuated ball valve would be relatively easy to implement, open much faster than any other alternative, make for a nice trigger. The disadvantages include that you are tied to some sort of air pressure system, the cost, and maybe safety (You can easily accidentally cut someone if you have pneumatically actuated pistons). I think this is a good option if you are planning to use some sort of air pressure system, which I think is the right way to go if you are willing to accept higher costs.

(I also have another idea where the trigger would be pneumatic, but it's based around a very non-standard setup and probably is not viable.)

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Re: Water cannon numbers

Postby the oncoming storm » Sun Feb 15, 2015 2:15 pm

As for blaster water usage/ range efficiency I think an LPD/ linear piston would be the absolute best. But the only working concept for a practical blaster using it was Ben's LPD prototype that CA99 owns and with no official stats given on SSC or WWN.

(Ben, Your calculations on the 150 are wrong, range is 35' and output 3.5oz/s or 10 ft/X)

The current efficiency record in a pressurized blaster is the Super Soaker 20 at a whopping 73.3ft/X, and Super Cannon 2 the lowest at 0.6ft/X.
This demonstrates just how much drag forces are compound at longer distances.
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Re: Water cannon numbers

Postby SSCBen » Sun Feb 15, 2015 3:59 pm

the oncoming storm wrote:As for blaster water usage/ range efficiency I think an LPD/ linear piston would be the absolute best. But the only working concept for a practical blaster using it was Ben's LPD prototype that CA99 owns and with no official stats given on SSC or WWN.

(Ben, Your calculations on the 150 are wrong, range is 35' and output 3.5oz/s or 10 ft/X)

The current efficiency record in a pressurized blaster is the Super Soaker 20 at a whopping 73.3ft/X, and Super Cannon 2 the lowest at 0.6ft/X.
This demonstrates just how much drag forces are compound at longer distances.


That LPD blaster was much worse than I expected it to be. I don't think I did any tests with it beyond checking that it worked. For LPD to be even slightly practical, we're going to have do do something like make it out of aluminum to reduce weight. PVC just doesn't work with the idea.

Thanks for pointing out the XP 150's numbers seem off. I used numbers from iSoaker.com and a few I collected myself (e.g., the SS 300's range comes from tests I did). The output of SuperCPS was not measured and instead comes from an calculation I made based on my estimate of the pressure (so it could be wrong, but it seems at least roughly correct). Some of the outputs were adjusted because it was literally impossible to get the given range at that output. The reason I adjusted the numbers was because the pressure drops in air pressure blasters. The output is averaged over the entire shot, and it's going to be higher at the beginning of the shot when the pressure is higher. This explains why the range are "impossible": they can't be achieved with the average output, but the peak output will do it. So, I increased some of the outputs of air pressure blasters to account for this. It wasn't done in any scientific way, and it looks like the numbers I had for the XP 150 were taken straight from iSoaker.com. Yours seem more in line with experience. In a way, this is good news, as it shows efficiency drops off less than I thought. (Thinking about it, I can actually make an estimate for the peak pressure based on the average pressure. Let me do this and see if it helps get more accurate figures.)

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Re: Water cannon numbers

Postby HBWW » Sun Feb 15, 2015 4:41 pm

I made a test shot that went a few feet farther than my CPS 2000 (using a PVC 1/2" barb as a nozzle, not optimal but was the best I had), and even with the piston replacement I made, it still leaks. That's the only thing worth knowing at this point and I'm not going to waste additional time and money. I might be willing to test it using PVC with a smoother inner wall, but it's probably not worth the time, effort, and money at this point (if I can even find said PVC) since the original setup had a smoother PVC inner wall and still couldn't seal. I've dumped about $100+ worth of parts at this thing and it's going nowhere. Plus it's way too heavy and unwieldy to be of use on any field.

If you want it, let me know when you get to a community war. I'll figure out how much money it's worth in parts and sell it off.

The future of practical homemades goes more towards the CPS direction, IMO. It's just a much more efficient use of the space, and PVC is not optimal at all for holding any sort of air pressure. We need lighter and better plastic.

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Re: Water cannon numbers

Postby the oncoming storm » Mon Feb 16, 2015 12:14 am

CA99 I appreciate the offer to sell it but I am not in a position to buy it nor would I if I could. My thoughts on the concept and prototype are that it was let down by poor quality parts that we were stuck with thanks to limited time and a reasonable budget which kept us from getting quality ready made parts.

My plans for experimenting would be to get a Hydro Cannon and convert it to an LPD by cannibalizing a WW Argon for the piston and tube assembly and rigging up a 24oz bottle on the back for the air chamber, add a Schrader valve to the mix and presto! You have a well made proof of concept that doesn't weight 10+ lbs empty.

the sad thing is I need disposable income before I can afford even this low level of experimenting with it, and Argons are hard to come by (at least till they hit stores again later this year).
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Re: Water cannon numbers

Postby Cochise » Thu Apr 30, 2015 2:30 pm

I just want to know how efficient these are in actual combat. They look quite devastating, but I wouldn't want to carry one around.

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Re: Water cannon numbers

Postby SEAL » Thu Apr 30, 2015 4:04 pm

Well that depends on what kind of game you're playing. If you have a large team, then it would make sense to have one person (preferably the strongest on the team) carry a cannon and unleash water hell upon the enemy while being protected by regular troops. A water cannon is capable of taking out multiple people with one shot, so if you were playing 1HS you could use it to rack up a hit or two to gain the lead, then go on the defensive. In most cases though, it's not very practical to have one. You only get one shot, then you have to refill for several minutes. And prior to firing it, you have to lug around all that weight. You'd probably need to carry some kind of small blaster as backup too, which adds even more.

In community wars we've only used them in scenario-type rounds, like Hold the Line, or the naval battles we've done at Soakemore. They have made a few hits, but in those rounds you can just set it down and pick up something else after firing. You could do that in a regular battle too, but then the enemy could steal it.
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