WaeV's APH

Homemade water gun threads that are notable.
User avatar
WaeV
Posts: 29
Joined: Sun Mar 29, 2009 4:01 am

WaeV's APH

Post by WaeV » Sat Apr 04, 2009 10:41 pm

Hey guys! I just built my first APH, but the results aren't very spectacular. Perhaps you can help me figure out what's wrong?

I'm getting about 20 ft range no matter which nozzle I use; 1/8, 3/16, 1/4, or the 3/4 pipe with no nozzle.

here's a schematic. I had to use so many adapters on the pressure tanks because Home Depot had a lousy selection of pieces in stock. I ended up having to drive 45 minutes to a Lowe's anyways, because HD didn't have any check valves. >_<

Image
Image

User avatar
Goldfish4209
Posts: 88
Joined: Thu Jun 05, 2008 12:45 am

Re: WaeV's APH

Post by Goldfish4209 » Sun Apr 05, 2009 12:39 pm

Your water gun has three pressure chambers. That means more power, but also much more pumps to fully pressurize it. Maybe you aren't pumping enough. For my APH, which only has 2 pressure chambers, I need to pump 70 to 100 times.
Current Arsenal: Liquidator, MI Flash Flood x2, APH x2, CPS 1200

User avatar
WaeV
Posts: 29
Joined: Sun Mar 29, 2009 4:01 am

Re: WaeV's APH

Post by WaeV » Sun Apr 05, 2009 2:45 pm

It gets really hard to pump after about 10-20 pumps, I wasn't really counting. Even then, it just seems to break up at those pressures. I get 20 feet for the first 8 seconds or so when I use the 1/8" nozzle. Could turbulence be a problem? When I look down the tube I can see some PVC cement along the walls (my first time cementing PVC).

Here's a video: http://www.youtube.com/watch?v=aicfg2qoCv4
Last edited by WaeV on Sun Apr 05, 2009 4:07 pm, edited 1 time in total.
Image

User avatar
Silence
Posts: 3825
Joined: Sun Apr 09, 2006 9:01 pm

Re: WaeV's APH

Post by Silence » Sun Apr 05, 2009 5:14 pm

Wow, that's a cool video.

It looks like your pump is narrow enough, so I think you're reaching suitable pressures. Also, the number of pressure chambers really shouldn't matter.

The problem probably lies with the nozzle. It looks like your stream is 1/4" or so in diameter; try 3/8" or larger.

I've never been able to drill a smooth nozzle, which is necessary for a clear stream at high pressures. If that's also a problem for you, consider using a metal pipe nipple. You'll need some type of threaded reducer to hook it up, though.

User avatar
WaeV
Posts: 29
Joined: Sun Mar 29, 2009 4:01 am

Re: WaeV's APH

Post by WaeV » Sun Apr 05, 2009 5:36 pm

yeah, looking at the video at 1:20 I can see some odd things going on with the spray; it doesn't look right until the pressures drop. I'll see about getting a better nozzle, and try to smooth out the current one until then.

I like the small nozzle because I can keep up with the pressure by pumping. Would a bigger nozzle achieve more range?
Image

User avatar
Goldfish4209
Posts: 88
Joined: Thu Jun 05, 2008 12:45 am

Re: WaeV's APH

Post by Goldfish4209 » Sun Apr 05, 2009 7:17 pm

^ Sometimes. If the nozzle is too big, range will go down. Of course, if the nozzle is too small, you can't soak anyone. My favorite size is 3/8 inch.
Current Arsenal: Liquidator, MI Flash Flood x2, APH x2, CPS 1200

User avatar
WaeV
Posts: 29
Joined: Sun Mar 29, 2009 4:01 am

Re: WaeV's APH

Post by WaeV » Sun Apr 05, 2009 9:02 pm

The biggest I used was 1/4, and i was using 1/8 for the shot.
Image

User avatar
Silence
Posts: 3825
Joined: Sun Apr 09, 2006 9:01 pm

Re: WaeV's APH

Post by Silence » Sun Apr 05, 2009 10:54 pm

See our page on physics and water gun nozzles if you're interested.

A rough explanation: the ratio of momentum (from the stream's volume) to air drag (from the stream's surface area) increases with the diameter. In practice, all streams break up easily at high pressure; but in a sense a larger stream can "expend" the water on its edges.

As Goldfish mentioned and as you may have noticed from the riot blast, massive apertures aren't good either. If there's any limit on the flow, it should be at the nozzle, not a narrow barrel or trigger valve. That's why Supercannon II and firehoses perform well with 1" streams, while Flash Floods and riot blasts simply peter out.

User avatar
cantab
Posts: 1492
Joined: Fri Oct 19, 2007 1:35 pm

Re: WaeV's APH

Post by cantab » Mon Apr 06, 2009 4:29 pm

Your pump seal is dodgy. There's water spurting out the end! That may or may not be the cause of your range shortage, but it's still an issue.
I work on Windows. My toolbox is Linux.
Arsenal:
Super Soaker: XP215, 2xXP220, Liquidator, Aquashock Secret Strike M(odded), Arctic Blast M, CPS1200, CPS2100, SC Power Pak, 3l aquapack, 1.5l aquapack
Water Warriors: Jet, Sting Ray M, Shark, Argon M, Tiger Shark, PulseMaster
Others: Waterbolt, The Blaster, Storm 500, Shield Blaster 2000, generic PR gun, generic backpack piston pumper (broken), 3l garden sprayer M, 10l water carrier:

User avatar
WaeV
Posts: 29
Joined: Sun Mar 29, 2009 4:01 am

Re: WaeV's APH

Post by WaeV » Tue Apr 07, 2009 12:09 am

I tried it with a 3/8" nozzle today and the effect was essentially that of the riot blast - the stream could only be maintained for a second or so. i want a blast that can be sustained if not as fast as I pump than at least as long as five seconds.

i definitely need to fix the pump. I have two o-rings; the first one stays on the rod okay but leaks a bit, so i added a second which helps but is a pain to keep in the groove. Everytime it pops out it's a combination of the groove taking up too much space and not holding the ring tight enough. I've tried replacing the o-ring, maybe i'll try flipping the rod over and using the other end.

Also, while 3 PCs may seem like that much extra space, I don't think it really is. I decided on 3 PCs when Home Depot didn't have any 4" caps and i was forced to use 3". I imagine it comes out to approximately the same volume.
Image

User avatar
Silence
Posts: 3825
Joined: Sun Apr 09, 2006 9:01 pm

Re: WaeV's APH

Post by Silence » Tue Apr 07, 2009 12:53 am

You can't conserve water and get maximum range at the same time. Look at Supercannon II, which I linked to above: 73 feet of range, but the shot only lasts a fraction of a second.

User avatar
WaeV
Posts: 29
Joined: Sun Mar 29, 2009 4:01 am

Re: WaeV's APH

Post by WaeV » Tue Apr 07, 2009 12:56 am

Ah, ok. So which nozzle would you recommend for all-around use? 3/16 seems pretty good from what i've tested.
Image

User avatar
Silence
Posts: 3825
Joined: Sun Apr 09, 2006 9:01 pm

Re: WaeV's APH

Post by Silence » Tue Apr 07, 2009 6:48 pm

Yeah, if anything, shy a bit on the narrow side instead of aiming for maximum range. You'll get nearly the same range but you won't waste as much water.

As far as actual numbers go, I can't really offer much advice - predicting ranges gets really complex, so trial and error is the best option.

User avatar
cantab
Posts: 1492
Joined: Fri Oct 19, 2007 1:35 pm

Re: WaeV's APH

Post by cantab » Tue Apr 07, 2009 7:35 pm

Oh yeah, silly question, but are you measuring ranges with the gun angled or level? A level range of 20 feet isn't so bad.
I work on Windows. My toolbox is Linux.
Arsenal:
Super Soaker: XP215, 2xXP220, Liquidator, Aquashock Secret Strike M(odded), Arctic Blast M, CPS1200, CPS2100, SC Power Pak, 3l aquapack, 1.5l aquapack
Water Warriors: Jet, Sting Ray M, Shark, Argon M, Tiger Shark, PulseMaster
Others: Waterbolt, The Blaster, Storm 500, Shield Blaster 2000, generic PR gun, generic backpack piston pumper (broken), 3l garden sprayer M, 10l water carrier:

User avatar
WaeV
Posts: 29
Joined: Sun Mar 29, 2009 4:01 am

Re: WaeV's APH

Post by WaeV » Tue Apr 07, 2009 10:36 pm

I wasn't measuring, I just eyed it. It seemed to go a bit further than theXP 240 that I was using.

It's actually more like 30 feet, now that I think of it. A friend is getting some nozzles drill-pressed for me, then lined with copper for smoothness. I'll have him start with a 1/4" hole, but it will be smaller due to the copper.
Image

Post Reply