Stream Speed Standard

[DX]

Originally posted at Soaker Media and iSCF:
[It's going to be a pain to track 3 topics, but I support all forums and I expect that this will get the most analysis at this forum]

I was thinking about creating a standard formula for stream speed, so we can base it off math, not eyeballing it. Stream Speed is such a crucial stat, yet you almost never hear about it.

I was thinking about having the time it takes a CPS 2100, 4100, or similar gun's stream to cross the 30ft. mark as 1x stream speed. The only major variable is the size of the stream, as a 20x can travel faster or slower than a 5x stream, for example. But now that I think about it, the difference is not that great because the stream is still coming out of the same pc which has a set amount of power. Maybe measure stream speed with the largest setting possible on each gun, or the smallest? Feed me some ideas...

Maybe use a smaller gun to set 1x? I really want to do this, to finally give us a way to rate this often unheard-of stat.

[ZOCCOZ]

I think I mentioned stream speed aswell a few months ago on isoaker.com in one of my rants about pressure power. FPS is already universal standard for measuring energy/muscle power in paintball, archery, airsoft and firearms. I suggested 1x as a universal comparison, since one could create a custum test nozzle that can be applied/adapted to most soakers. For comparison it has to be a unified nozzle size, since the heavier the projectile, the less the FPS will be.
At isoaker.com:

I would measure out 30ft and shoot at the barn wall, or the fence. I would run quite a few tests and average the times, so that the margin of error could be reduced.

Distance should have nothing to do with measuring it, since the FPS is measured directly infront of the nozzle.(If you decide you use a chrono).
In any case, getting the actual FPS would not be hard with all those chrographs out there. All one has to do is wanting to spend $60-$200 depending on the Chrono tool typ.
This chronograph will work definatly on a soaker:

This chronograph should work on a soaker:

[Ben]

I've measured stream speed before (incorrectly calling it velocity which actually is a vector, not a scalar). This statistic is fairly useful, but not very useful because the speed does decrease as the shot is carried down. A statistics like how long it takes to get to 30 feet will be more useful because it is almost like the 0 to 60 MPH statistic in cars. Stream speed will be most useful when someone can make a graph of the speed as it decreases. The easiest way I can think of doing that is to make a position function and taking the derivative of it (i.e. application of basic Calculus).

I do not believe that you should reduce nozzle sizes to get a more "comparable" speed. That would mean modifying most any water gun to be shot. Such a nozzle orifice size would be great for homemade water guns though. We should set the nozzle orifice size not to a drill bit size such as 1/8" though, because it is harder to get your water gun to shoot at a certain output. Remember too, that the area of the nozzle orifice increases with the square of the radius. If we make a graph of nozzle orifice sizes vs. stream distance now like I did in my old "Streams" article, it might be best to display nozzle orifice size as (d/2)^2 which would be more comparable to output.

I'll be looking into the position function for a water stream. This would explain much about how air drag affects the water stream.

[DX]

The maybe keeping the nozzle sizes as they are and testing them would be preferable to forcing a single size. I suggested 30ft because not all guns can make it out to 40, 50, or 60. Whatever is the shortest range that all tested guns can reach should be the standard displacement. Once the stream speed falls around the end of the range, it gets more mathematical and I'd rather not get involved with all that. That is necessary for the complete speed of the stream, but a 0-X ft is good if you want a simple, practical, usable stat.

[ZOCCOZ]

The decision is yours. The reason why i personaly would prefer measuring FPS from the front of the nozzle is becasue of a more accurate reading. Plus in order to call a stat officialy FPS, it has to be measured from the nozzle. The speed of a distance of 30 feet will already be affected by wind and even lamination. But I supose it should be enough for basic gaimg stats.

Posted on SMF:

Plus I think hat people should be allowed to say the fps on different nozzles. Like for modded guns if they shoot slower on 1x nozzles and you don't use them, why bother using that nozzle. As long as you specify the size it should be okay.

People can of course measure it from different nozzles. But lets say it that way, FPS is unfortunatly not always proportional when reducing or increasing size. A pure energy data comparison would no longer be possible. At least not for purely accurate stats(or as acurate as possible.)

Like I said, Chonos are only an option. I might buy one(prochrono) myself, since I have to use it sooner or later for my martial arts data.

[DX]

See other posts. I knew it was going to be a headache having 3 of the same yet different discussions going on at the same time.

[joannaardway]

Yes, this is an old topic, but I'm bringing new stuff to it so...

I present the easy way to calculate stream speed:

flow/nozzle area = stream speed at the nozzle.

All the units have to be the same (so you can't mix cubic inches and fluid oz) so I recommend metric units:

flow in cubic metres per second/nozzle area in square metres = stream speed in meters per second.

Just use any basic converter to find the right units (google is good)

Find your answer and convert that back to ft/sec or whatever you want.

I'm going to conduct some tests on stream speed/stream deceleration/range sometime, so you'll get the results back from this then.

[Ben]

Flow would be output converted into a volume per second, correct? I see how that would work. I've used this equation in school before, but had forgotten about it now! Great idea.

I'm thinking this'll be used often.

[Silence]

Nice idea--it's simple and elegant, so I like it. Similarly, in standard units:

cubic feet per second / square feet = feet / second

And in more "common" units, that would be:

(gallons / second) / (19.25 * square inches) = feet / second = 0.68 * miles / hour

And the more "common" units in the metric/SI system would be:

(liters / second) / (10 * square centimeters) = meters / second = 3.6 * kilometers / hour

[joannaardway]

Of course, the same output through a smaller nozzle = more stream speed, thus more range

More output through the same nozzle = more stream speed and more range <- This is why the K-mod adds range.

Example:

My CPS 2700 when 20x power modded has a nozzle 9.5 mm across, and 600 ml output per second.

0.0006 m^3/sec /nozzle area (0.00007 m^2) = 8.6 m/s or 28 ft/s nozzle stream speed.

[isoaker_com]

joanna's simple and clear calculation works for estimating nozzle exit speed. The main sources of speed errors would be in output measurements and in nozzle-diameter measurements. It is also trickier to calculate for the more complex nozzles (i.e. shower head, fan, 'typhoon', etc.) Also, while exit velocity is nice to know, as noted above, different streams decellerate at different rates depends on their cohesion. Spreading, riot-blast type streams undoubtedly slow much more quickly than a solid, laminar stream. Though exit velocity is a nice stat to know, perhaps what would be good to also know if the approximate speed of a stream or how long it takes for a stream to reach a blaster's 'functional' range.

Functional range of a blaster is, of course, a little more subjective and depends on the blaster in question. I still also have some reservations about listing stream speeds since, IMO, it is already implied (well, the average speed) in level shot ranges. A given number for speeds in m/s or ft/s don't carry much practical meaning for me when I think of streams. Then again, in the typical battles I've been involved with, shot time and output tend to weigh more than stream speed as most stock soakers seem to fire at similar speeds.

[DX]

My CPS 2700 when 20x power modded has a nozzle 9.5 mm across, and 600 ml output per second.

0.0006 m^3/sec /nozzle area (0.00007 m^2) = 8.6 m/s or 28 ft/s nozzle stream speed.

So let me, representing the non-math people here, figure out how to use this:

When measuring the nozzle diameter in mm, you convert it to m, and when measuring in mL, convert that to kL? I don't understand why you would convert to kL other than to keep the unit sizes the same.

So, if you don't want to think about what's going on, you can do this:

[[x rating in mL/100,000] cubed]/[[nozzle area in mm/1,000,000] squared] = initial stream speed in m/s?

[Silence]

@ Duxburian: Umm...I'm slightly confused by that formula at this point. How did you arrive at those coefficients? Also, what output is one X?

Also, I don't see the "/ seconds" anywhere in there...I know where it should go, but others might not know. Overall, I am unsure of the accuracy of that formula since the numbers seem pretty random to me, no offense.

[DX]

[[x rating in mL/1,000,000] cubed]/[[nozzle area in mm/1,000,000] squared] = initial stream speed in m/s?

0.0006 m^3/sec /nozzle area (0.00007 m^2) = 8.6 m/s or 28 ft/s nozzle stream speed.

^What's in bold was me reasoning out the way you get Joanna's example. You don't understand it because it has the math whittled out of it. Basically, what I thought she did was take the nozzle area in mm and convert it to meters, which would be dividing it by 1000 and then dividing that by 1000, AKA dividing by a million. Then you square that answer and hold onto it.

Then I thought you take the x rating in mL and convert that to kL, since you had to convert mm to m. To do that, you would divide by 1000 and then another 1000, AKA dividing by a million. You cube that and hold on to it.

Then you take the answer you just got and divide it by the first answer. I got the same answer as Joanna using that reasoning. However I made a mistake in posting 100,000 instead of 1,000,000. So to fix it up:

[Output in mL/1 million] cubed divided by [nozzle area in mm/1 million] squared = stream speed in m/s

[Silence]

Ah, I see what you did now...so thanks for clearing that up. Earlier, I posted that another version of joannaardway's formula but with more common units was:

(liters / second) / (10 * square centimeters) = meters / second = 3.6 * kilometers / hour

And yours is still missing the seconds for the output--you have the volume, but not the time. Thus, it should be:

[Output in mL/ [1 million * seconds]] cubed divided by [nozzle area/1 million] squared = stream speed in m/s

At least, I think that's what it's supposed to be. Earlier, I had also assumed that the "x" in your formula (now changed to "output") was the actual X of the XP 70 that is used to measure the output of all other soakers these days.