Piece of @#$% Canteloupe Cannon!

Post questions and info about pneumatic (compressed gas) powered launchers here. This includes discussion about valves, ratios, compressors, and anything else relevant to launchers powered by compressed gas.

Postby draculon » Fri Jun 03, 2005 10:32 pm

<blockquote id="quote"><font size="1" face="tahoma,verdana,arial" id="quote">quote:<hr height="1" noshade id="quote">Originally posted by DR
The initial dry test-fire was at a mere 60psig, and wasn't as loud as I expected. The second dry test-fire (at 80psig) proved to be a little louder, and moved the entire assembly back about an inch, even though one leg bracing the table that it was sitting on. The third dry test-fire (at 100psig) ...was pretty damn loud. My dog pissed herself, and one of my neighbors came over to ask me what the hell I was doing, and if I was alright. Besides, my 2 gallon compressor will probably drop it's nuts if I attempted any more tests with it.
<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">

Dang, good to hear that it works well. What size are the chambers? I'm guessing that the barrel is in the 6 in region. Looking at the pictures it appears that the chambers are the same size as teh barrel.
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Postby BewareOfDog » Sat Jun 04, 2005 12:19 am

<blockquote id="quote"><font size="1" face="tahoma,verdana,arial" id="quote">quote:<hr height="1" noshade id="quote"><b><u> draculon</u></b>
...Dang, good to hear that it works well. What size are the chambers?
<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">Each chambers is 60" of 6" diameter SCH40 pipe. Both of these, along with an estimated 75 cu. in. of volume from each of the 3" diameter portion of the chamber leading to (and into) the valve give me an estimated 3,540-3,550 cu. in. of chamber volume.

The barrel is 75" total length, but only 66" of that is considered usable barrel volume because the pipe flares out at the end for about 9". So I would guess that the barrel is 1866 cu. in.?

That would give it a C:B ratio of approximately 1.9:1?
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Postby ybott » Sat Jun 04, 2005 2:21 pm

Wow, thats gona be LOUD !!, a true BEAST DR, well done !!

p.s. have you tested your mini hybrid yet (.233:1 CB ratio) ?
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Postby pbmann123 » Sat Jun 04, 2005 4:32 pm

wow dr you never cease to amaze me. god bless you and your very large cannons.
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Postby BewareOfDog » Sat Jun 04, 2005 5:27 pm

<blockquote id="quote"><font size="1" face="tahoma,verdana,arial" id="quote">quote:<hr height="1" noshade id="quote">Originally posted by ybott
[br]p.s. have you tested your mini hybrid yet (.233:1 CB ratio) ?
<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">Yes...and no. The 2" SCH80 Union is a total piece of [excrement]! The flange area is divided by a deep groove, unlike the larger unins which have a large flat edge. I cannot get it to hold enough pressure for even a 2x mix (15psig), as it leaks too rapidly.

I've never had a combustion launcher that I couldn't get to fire, except for this one. I'm going to scrap this one, but I may try another with a larger union though, soon.
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Postby draculon » Sat Jun 04, 2005 6:29 pm

<blockquote id="quote"><font size="1" face="tahoma,verdana,arial" id="quote">quote:<hr height="1" noshade id="quote">Originally posted by DR
[br]Each chambers is 60" of 6" diameter SCH40 pipe. Both of these, along with an estimated 75 cu. in. of volume from each of the 3" diameter portion of the chamber leading to (and into) the valve give me an estimated 3,540-3,550 cu. in. of chamber volume.

The barrel is 75" total length, but only 66" of that is considered usable barrel volume because the pipe flares out at the end for about 9". So I would guess that the barrel is 1866 cu. in.?

That would give it a C:B ratio of approximately 1.9:1?
<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">
DR, two questions:
1. Where do you get the money for all of those parts?
2. Where did you get the 3in valves?

That's a pretty big air volume. I ran the numbers through GGDT and it says that a 10 kilogram canteloupe (or other melon) will shoot at 111 FPS with a muzzle energy of 4203 ft*lbs. I'm assuming that that will decimate even the most fortified target. I also checked under projectile velocity, but it said that the projectile will start to decelerate dramatically after 10 milliseconds. If you want major devastation, you should probably shoot from a close range.
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Postby ybott » Sat Jun 04, 2005 6:52 pm

damn..that sucks about the hybrid DR! , well if it's any consulation(sp?) i'm gonna try it myself (almost identical spec...BUT BIGGER..hehe, i.e. a 26" chamber and 7ft barrel)

thanks for replying tho !
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Postby UnrealityisReal » Sun Jun 05, 2005 11:57 am

Thanks for answering my question Dr. That cannon is going to be friggin awesome when it's finished. I think that it's cannons like these that make this a great forum.
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Postby BewareOfDog » Sun Jun 05, 2005 1:34 pm

<blockquote id="quote"><font size="1" face="tahoma,verdana,arial" id="quote">quote:<hr height="1" noshade id="quote"><b><u>draculon</u></b>
DR, two questions:
1. Where do you get the money for all of those parts?
2. Where did you get the 3in valves?<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">
1. I work ;)
2. From an Irrigation Supply store in town. They were accidently shipped with no solenoids (or some BS like that) and were offered to me for $33 a piece. (Which is sad when you think about it, because most places want $120 - $140 a piece for 3" valves. Just goes to show you how much they mark a product up)

I ran numbers through GGDT also. The canteloupes average about 1900-1950 grams (1.9-1.95 kilograms), so I don't know where or why you came up with <b>10</b>[:0] kilograms. It says that my projectile velocity will be 375 fps, with a muzzle energy of 9,308 ft. lbs.

Using the Gun Optimizer and checking Fixed Chamber, I would need to increase my barrel length to a whopping 35+ feet.
The muzzle velocity would increase by 171 fps ( 546 fps ), and the muzzle energy would increase over 2 times to 19,710.8 ft.lbs.

I'm not sure if the Saturn destruction will be possible though. I planned on paying to have it towed away afterwards, but really don't want to pay to tow it <i><b>to</b></i> somewhere beforehand, just to destroy it. It's parked within the city limits, and I really don't feel like getting into trouble.
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Postby draculon » Sun Jun 05, 2005 3:15 pm

Oh, I guess I put in a bit too many zeros.
Of course, I know you work, i don't unfortunately, at least not untill another 7 months...
The weight issue was that I was thinking watermelons that weighed 10 kilograms. I must be having an off week or something.
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