Stream Lamination in homemades

Build a homemade water gun or water balloon launcher and tell us about it.
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StormGlorious
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Stream Lamination in homemades

Post by StormGlorious » Thu Feb 21, 2008 7:57 am

When building my latest homemade the APH 1000, I discovered........
That if a length of tubing is inserted into the ball vavle with the endcap on the end then your gun will achieve much larger ranges than if on were to put the endcap straight into the ball valve.
Now I'm not sure if this is a common fact or if it is a new concept but if it is a new idea then I suggest you all incorporate it into designs from now on.

sbell25
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Re: Stream Lamination in homemades

Post by sbell25 » Thu Feb 21, 2008 8:24 am

I've noticed that Ben also uses a pipe nipple or a length of pipe between the valve and nozzle on his homemades, although I never did on my APH. Perhaps that's why I had poor stream lamination with endcap nozzles on it. I'll have to give that a try next time I build one.

Interesting bit of info, thanks for sharing!

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Drenchenator
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Re: Stream Lamination in homemades

Post by Drenchenator » Thu Feb 21, 2008 1:40 pm

Technically, all the CPS guns have a short piece of pipe after the nozzle. Laminar flow can be increased with a long straight section of pipe; the problem is that this can also slow down the flow by friction. But it looks like a short length might do something. I don't really see how much it would do though: The ball valve has the same inner diameter as the pipes that enter and leave it, so when open it should act as the exact same thing.

Ben uses pipe nipples because they're threaded on both ends, not to increase laminar flow. A conical nozzle would do a much better job at this because it decreases the inner diameter gradually over a length of pipe, which improves laminar flow at the orifice much more than this would--the sudden change from one diameter to a far smaller one creates a lot of turbulence.
The Drenchenator, also known as Lt. Col. Drench.

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Silence
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Re: Stream Lamination in homemades

Post by Silence » Thu Feb 21, 2008 9:42 pm

Like sbell25, I use male-threaded plugs instead of female-threaded end caps. I've never bothered doing it the other way, although I want to since it's hard to screw and unscrew the plugs because you have to grip a very thin rim.

I'm not sure how much of a difference it'll make, but I'll give a try sometime. I guess I just need that extra motivation to get a pipe nipple and endcaps. Thanks! :)

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SSCBen
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Re: Stream Lamination in homemades

Post by SSCBen » Fri Feb 22, 2008 4:12 am

Generally, you should see slightly improved range from using a pipe between the valve and the nozzle. The longer piece of straight flow does seem to help make the flow more laminar. I didn't do that as a design choice, rather, just because it was what I did when I put the thing together.

The thing to remember is that longer lengths do help, but you get diminishing returns in improved laminar flow because eventually it just straightens out. You also have to factor in friction and size, as Drenchenator said, so there's no real point to having a piece of pipe from the valve to the nozzle longer than 3 inches, though that value depends greatly on the size of the water gun. 3 inches would be more like 6 on Supercannon II...

Though, when making the original APH, I put straws in the nozzles to help lamination, but I didn't put them in permanent enough for them to keep. I think WaterWolf reported increased range from them, though I could be mistaken. I didn't think it made much of a difference, but I didn't measure either.

What matters for performance, more than anything, is having the right idea of what can help and then testing those things out. Varying nozzle diameters, and a bunch of other small things can make a big difference in range.

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StormGlorious
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Re: Stream Lamination in homemades

Post by StormGlorious » Fri Feb 22, 2008 7:33 am

After writing about this I came to the conclusion that a word which better describes this idea is more along the lines of "Stream Concentration".
I believe that the reason that this idea works, is in fact that pipe refocuses the stream after the turbulence created by the ball valve.

sbell25
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Re: Stream Lamination in homemades

Post by sbell25 » Fri Feb 22, 2008 7:50 am

I believe that the reason that this idea works, is in fact that pipe refocuses the stream after the turbulence created by the ball valve.
Yup, that's what Ben was talking about in his post.

Stream concentration and stream lamination are different terms for the same thing. Having a laminar stream means that it is as 'focused' as possible, giving you maximum range before it turns into a diffused spray.

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Silence
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Re: Stream Lamination in homemades

Post by Silence » Fri Feb 22, 2008 9:47 pm

The problem is that the nozzle is going to disrupt the stream all over again. You should try using small pipe nipples or lengths of tubing as the nozzles themselves, as I think was mentioned at the Downpour website (perhaps by sbell...), if you really want to reduce turbulence. I suppose I should try that too.

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Drenchenator
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Re: Stream Lamination in homemades

Post by Drenchenator » Fri Feb 22, 2008 10:08 pm

in fact that pipe refocuses the stream after the turbulence created by the ball valve.
The point of using a ball valve is that they don't produce turbulence at all--they don't restrict flow in any way and allow a straight path through. As long as the ball valve has the same size hole as the threads or sockets, it won't restrict create turbulence. It's as simple as that.

If the pipe does in fact decrease turbulence as suggested, it would make more sense for it to decrease the turbulence where the majority of it would be aside from the joint connecting the chamber to ball valve, at the nozzle.
The Drenchenator, also known as Lt. Col. Drench.

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StormGlorious
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Re: Stream Lamination in homemades

Post by StormGlorious » Fri Feb 22, 2008 11:44 pm

I actually originally used pipe nipples on the homemade however they just produced a riot blast effect. So I tried a smaller nozzle, an endcap, same result less output.
However when I put the length of tubing on I was amazed to see that it acheived a perfectly laminated super long range stream.

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MarsGlorious
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Re: Stream Lamination in homemades

Post by MarsGlorious » Sat Feb 23, 2008 12:10 am

Does it also help to try and make your gun as stream lined as possible?
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Drenchenator
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Re: Stream Lamination in homemades

Post by Drenchenator » Sat Feb 23, 2008 1:56 am

Yes, a linear design is the best. Nothing should obstruct the path of the water from the chamber to the nozzle; in fact you know the design will perform well if you can look through the nozzle and see the chamber when the valve is open! For further reading on this, I suggest Ben's Water nozzles and efficiency article.
I actually originally used pipe nipples on the homemade however they just produced a riot blast effect.
Did you put an end cap nozzle on it? Ben and I have both used pipe nipples to connect the valve to the nozzle with success. It should work just as well as a length of tubing because it is a length of tubing.
The Drenchenator, also known as Lt. Col. Drench.

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Silence
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Re: Stream Lamination in homemades

Post by Silence » Sat Feb 23, 2008 4:18 pm

StormGlorious, you may want to try new nozzles for both methods. I've got a feeling that, since you're using two different nozzles, the endcap one has a cleaner aperture than the plug one does.

If you're using pipe nipples for nozzles, make sure you get 1/4" or 3/8" ones - not full size, 1/2" ones. The point is to get a long, smooth bore for the nozzle itself, in the correct size.

sbell25
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Re: Stream Lamination in homemades

Post by sbell25 » Sat Feb 23, 2008 10:25 pm

I'm getting a little confused here. When people say 'pipe nipples', are they referring to a length of pipe with male threads on either end, or a hose barb/tail? The word seems to be getting interchanged in this discussion.
Like sbell25, I use male-threaded plugs instead of female-threaded end caps.
My method is a hose tail/barb. I've never used a plug as a nozzle before. Hose tails gave me a 10-15 foot increase in range on my APH compared to endcap nozzles, although my endcap nozzles were performing below average. I was probably drilling them wrong or something.

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StormGlorious
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Re: Stream Lamination in homemades

Post by StormGlorious » Sun Feb 24, 2008 12:00 am

By pipe nipples I was refering to Hose barbs, just clearing up confusion. (My mistake)

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