Summer 2009 Contest Discussion

[randompkguy]

ok, understood.

[Technician1002]

but I think that it is unfair to limit the building materials to pvc and abs.

As jrrdw mentioned.. It is fair if everyone has the same rules. You can build a better PVC cannon for power can't you?

I swim with my kids. We play by the same rules. It's fair. Disallowing my boat from the race is completely fair. It's a PVC contest. It should be fun. Can you beat the other contestants at the game using the fair rules?

How thick can you sleeve PVC for a 500 PSI barrel sealer? I expect to see some insane PVC creations.. I can't wait. If I were entering I would have a 500 PSI chamber with graduated sleeves with a 150 PSI pressure step between each layer.

6 inch outer would be 150 PSI, 4 inch would be 300, 3 inch would be 450, 2.5 inch, 500. The space between layers should keep the whole thing from exploding if one layer failed as the pressure redistributes into a combined space.

A 10 foot 2.5 inch barrel sealer at 500 PSI should pack a punch. A 3 inch piston with a 2.5 inch port into a 2 inch barrel 10 feet long has interesting possibilities. Plug it into GGDT You will want barrel supports and a sleeved barrel.


I do engineering for a living. Take up the challenge. I'm not entering this time due to schedule and budget. If I was entering, I would come to win if possible.

Get creative.. Come to win.. The power shoot off will require innovation to win.

[pat123]

6 inch outer would be 150 PSI, 4 inch would be 300, 3 inch would be 450, 2.5 inch, 500. The space between layers should keep the whole thing from exploding if one layer failed as the pressure redistributes into a combined space.

A 10 foot 2.5 inch barrel sealer at 500 PSI should pack a punch. A 3 inch piston with a 2.5 inch port into a 2 inch barrel 10 feet long has interesting possibilities.

yeah but a 10' long gun with a 6" outer diameter would not have a chance with the power vs size part of the competition.

[Technician1002]

6 inch outer would be 150 PSI, 4 inch would be 300, 3 inch would be 450, 2.5 inch, 500. The space between layers should keep the whole thing from exploding if one layer failed as the pressure redistributes into a combined space.

A 10 foot 2.5 inch barrel sealer at 500 PSI should pack a punch. A 3 inch piston with a 2.5 inch port into a 2 inch barrel 10 feet long has interesting possibilities.

yeah but a 10' long gun with a 6" outer diameter would not have a chance with the power vs size part of the competition.

True. This was given to inspire. There are ways to deal with limitations of PVC. I'm interested to see who has the biggest, highest pressure, and etc.

Remember doubling the absolute pressure in a given volume doubles it quantity of air stored. At 500 PSI, it may well store as much air as a larger tank at lower pressure. The high pressure has the pressure advantage. The same volume of air is delivered at a much higher average pressure.

The decimator is a prime example of this.

[PCGUY]

If you are SURE you are going to be entering, please PM me so I can get an idea of how big this is going to be.

Thanks!

[AtomicJew]

500 psi chamber to a 2 inch barrel
and only 10 feet of barrel?
are you designing a mortar? I can out penetrate that with 175 psi . . .
This config has supports but no need for sleeves to shoot a mile.


I have done years of shooting for penetration and distance with potatoes and other objects. The biggest factor in penetration is ammo design, not gun design.

Are any and all ammo groupped into a single category? I suggest splitting into two groups, "potato" and "other" or requiring that each gun submit a video of both types of ammo, or only allowing potato.

Also is there a set distance to fire from? 10 feet? 1 foot? twice the length of the ammo?

[Mr.Sandman]

So you are saying that you are using unsleeved pvc for 500 psi? Unless you are using like schedule 120 you have a tickng time bomb. And over penetrating the decimator at 175 psi? Im not one to put people down but im calling bs. Btw is that a pneumatic? if so is it a coaxial or what, i cant really tell from your blurry pics.

[inonickname]

I agree, I'm calling either BS or a misunderstanding somewhere along the line.

[spudtyrrant]

500 psi chamber to a 2 inch barrel
and only 10 feet of barrel?
are you designing a mortar? I can out penetrate that with 175 psi . . .
This config has supports but no need for sleeves to shoot a mile.


I have done years of shooting for penetration and distance with potatoes and other objects. The biggest factor in penetration is ammo design, not gun design.

Are any and all ammo groupped into a single category? I suggest splitting into two groups, "potato" and "other" or requiring that each gun submit a video of both types of ammo, or only allowing potato.

Also is there a set distance to fire from? 10 feet? 1 foot? twice the length of the ammo?

he has a 1 inch barrel 4 feet long actually and e is shooting at 1/4 inch steel his gun gets 900-1000fps with steel ball bearings i doubt that cannon could even come close to penetrating a piece of 1/4 plate steel even @ 175psi with the right ammo.

the force/area for the decimator is much higher than the force/area for the cannon pictured i guarantee it.

http://www.spudfiles.com/forums/the-beh ... ter,0.html
this cannon couldn't pierce the side of a compressor tank which is actually closer to 1/8inch steel

[jackssmirkingrevenge]

I doubt that cannon could even come close to penetrating a piece of 1/4 plate steel even @ 175psi with the right ammo.

That's the crux of the matter.

[WOW!!]

So then were do we submit the entries?

[AtomicJew]

Calling BS?!? This is a contest, of course I intend to back up what I say.

But no, I will not mention how.

0.015" Steel flashing. 140 psi. Target distance 80 feet.
Edited: I corrected the thickness of flashing, obviously its .015 not .15 inch (28 gauge)

[velocity3x]

Comparing the edge of the tear in the metal to the size of the screw head in the lower / right of the pic makes me think the metal is somewhere around 20-24 gauge. Apologies if I'm wrong.

[mobile chernobyl]

i would agree with that - from that angle it doesn't even look like 1/8" sheet.

A better angle of that shot is needed to truly get an idea of the penetration power.

[Hotwired]

Come on. Don't make any specific cannon claims in here, leave it for your entry.