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Posted: Sun Jul 30, 2006 2:46 pm
by SSCBen
Posted: Sun Jul 30, 2006 4:29 pm
by DX
Sweet, can't wait to see the gun in action! 
Also fudge, because I procrastinated gluing my own new water cannon for so long. In fact, I'll do that today, since that has a good shot at 70 and now I need some defense for the Regional War. At close range, I wouldn't trust the reeds to protect me from a large water cannon blast. 
Posted: Sun Jul 30, 2006 5:04 pm
by forestfighter7
What excactly is the Supercannon2? I take it that it is some kind of very powerful home-made but beyond that, I don't know anything about it. :laugh:
Posted: Sun Jul 30, 2006 5:07 pm
by SSCBen
Soon you will know what Supercannon II is. Until I post the pictures, all you need to know is that it's a water gun designed completely with efficiency and performance in mind. I say this because my normal computer is being used and I can't copy the images and videos from here.
You know I'm the king of procastination. The first Supercannon was completed last October and didn't work too reliably. I announced that the piston version was being worked on in January and never completed it until now. In honesty, I was waiting for someone else to do this for a while. A few days ago I decided to finish this up though. I'll also admit that I mistakenly thought that piston cups didn't fit correctly, when in fact they were the perfect size. That put me off for a few months.
The piston cups work better than expected. Buying piston seals from McMaster-Carr was a good idea. You get what you pay for here, and my $25 piston assembly is well work the price and was easy to build. Lubrication was also easy because I had plenty of petroleum jelly around. Remember too, that petroleum jelly is only a bad idea to use on natural rubber. The Buna-N rubber of my piston cups is synthetic. Always check chemical compatibility.
I haven't looked at the frames of the video yet to get exact shot times, but a regular shot with the 1/2 inch conical nozzle likely is 50X output judging by the shot time. We tested a regular threaded cap, but the stream was turbulent and only shot a lowly 55 feet. We also tested it without a nozzle and it shot the entire tank in about half a second. My rough mental calculation puts the output of that at 200X. ???
We can crank up the pressure and optimize the orifice diameter still. This was nowhere near this water gun's full potential. 80 feet is easily within reach with 20 PSI more pressure and an optimized nozzle orifice diameter. Not that it would be practical, just interesting.
I'm not going to bring this to the Regional War if I attend unless I upgrade it to a CAP system. So don't worry. While it is quite comfortable to use and will not be matched in performance, unless you have a reliable repressurization system, you wouldn't get far.
Edited By Ben_ on 1154297381
Posted: Sun Jul 30, 2006 5:23 pm
by DX
You just reminded me of something. I've never actually shot a water cannon with a normal nozzle. I've been reporting ranges with the 1" riot blast...now I'm curious what my leaky first one gets on a smaller nozzle. I just finished gluing that 2nd one finally, so I'll have to use the 1st for right now. It still has a darn air leak from that bad glue, and I'm not going to bother wasting more glue to fix that completely. The 2nd design is better, and my 3rd will be better yet.
I want to make my 3rd water cannon with a piston, however, I need to get McMaster-Carr access. It is a shame that they don't have a conventional store, for I probably could bike there if it were within 40 miles. I also don't fully understand how to make the piston assembly for a large 4" diameter, having never seen such a large one of course. My "Death Cannon" won't be the most powerful thing around, however it will have the same battle practicality of the 3rd generation Douchenator, being identical except for the piston and barrel. I have too many guns going at once... :laugh:
Posted: Sun Jul 30, 2006 5:45 pm
by SSCBen
A riot-blast at 70 PSI lasted approximately 4/15 of a second from a frame-by-frame analysis. With 3 liters in the pressure chamber (a conservative estimate), that'd be 375X. Okay, let's not talk about output anymore. Recoil-wise it wasn't as much as SuperCAP was, but that likely was due to the fact that SuperCAP's lasted for over two seconds and had a 1 inch diameter as opposed to a 1 1/2 inch diameter nozzle. That means more velocity, which translates into a bigger transfer of momentum.
I've edited in a few frames from a video and a short clip of one 70 foot shot.
Edited By Ben_ on 1154299716
Posted: Mon Jul 31, 2006 12:00 am
by sbell25
That thing is amazing. 375x output...that is so far above anything else it's ridiculous. Great job!
Posted: Mon Jul 31, 2006 6:27 am
by DX
iSoaker once mentioned something about output for shots under 1 second being cut. Like if it lasted half a second, the output would be divided by 2. But even 375/2 is still an impressive number.
Posted: Mon Jul 31, 2006 7:44 am
by SSCBen
Thanks for the praise everyone.
iSoaker does ones second burst output. I do average output over the entire shot interval, which in this case was a lowly 4/15 of as second (0.267 s). One second burst output is difficult to do and is deceiving many times (as this can be deceiving). I don't doubt that if I made a bigger version of this, it would get 375X burst output (it would be really long). Since there was only about 3 liters in the chamber, this would only be 100X output if we had to reduce to total water shot in one second. If I did one second burst output, my SuperCAP output would have been like 160X because I used the regulator bypass for more flow. So it goes both ways.
More coming soon...
Edited By Ben_ on 1154351424
Posted: Mon Jul 31, 2006 5:45 pm
by m15399
Could you please tell us the part numbers of the seals you used?
Earlier you said they were not what you were looking for... how did you fix the earlier problems?
Posted: Mon Jul 31, 2006 7:11 pm
by forestfighter7
Wow... Great Pics and great cannon. And now I DEFINETLY know what SupercannonII is :laugh: .
Posted: Mon Jul 31, 2006 7:22 pm
by SSCBen
I ordered two of part number 9411K28 according to the packing list I kept. At 9.24 each, these will set you back. They're well worth the price if you ask me. I do think that one is all that is necessary, but two would be more stable (I worried about rotation).
As for the problem, the problem was that I thought the seals would fit more loosely. These are tight fits. They should be tight fits. They're actually perfect for this. I used to think getting good seals from pistons was difficult, but this makes it easy. No leaking and less work.
Images of the construction of the piston will be made available tommorow. I did put a link to some big images at SoakerMedia, but that's not every picture of the construction and those images are very large.
Posted: Sun Aug 06, 2006 4:15 pm
by SSCBen
Just did some more testing. These two are separate shots. No glycerin was in the chamber when the output test was done. A video of the output test shot will be available. Videos would be great for measuring output of most water guns to get the exact duration, but when you're counting frames it gets real difficult.
These kids from across the street came over and talked to me for a minute too... they seem really interested.
95 PSI shot with 5% glycerin: 78 feet
Output at 100 PSI: 542 - 812X
The fact that the glycerin didn't add too many feet to the range was due to several reasons. There was a light wind from the side and against me. That however did not affect the distance too substantially. The real reason is probably because this water gun is extremely efficient to begin with, and while glycerin will help prevent the stream from breaking up, the water gun was so efficient that the stream did not break up much to begin with.
The output shot was incredibly powerful. If I didn't wear the strap I am sure I would have dropped it. This felt like a rocket was going off with me attached to it. That's probably because a water gun pretty much is a rocket.
I also measured the chamber size at the piston distance I had set earlier. The chamber hold approximately 3250 mL. That increases the 100 PSI output with the fire hose nozzle to 135X and my previous non-nozzled output to 406X.
Edit: Due to the low precision of the camera frames, I'm giving a range for the output. There's no way I really can determine exactly how long the shot lasted with only 15ths of a second precision. So I'm giving the shot time as 2/15 - 3/15 of second.
Edited By Ben_ on 1154900308
