A tale of two valves

Show us your pneumatic spud gun! Discuss pneumatic (compressed gas) powered potato guns and related accessories. Valve types, actuation, pipe, materials, fittings, compressors, safety, gas choices, and more.
iknowmy3tables
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Thu Sep 09, 2021 8:03 am

I'll cut to the chase, if you or a friend still use sprinkler valves show them this, I'll try to get a video to prove it if necessary.
I built these two cannons with a friend who wanted to make an air Cannon.
The small one was made for ping pong balls but my friend really wanted to try shooting tennis balls from it so we attached a stubby barrel.
The larger one is a cannon we made to fit in a golf ball

There's no comparison the smaller cannon shoots with way more force

IMG_20210909_085230.jpg
Here's a link to the QEV I used currently selling for $38 for 5 valves
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farcticox1
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Fri Sep 10, 2021 3:32 pm

QEV for the win
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Anatine Duo
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Sun Sep 12, 2021 7:40 am

That stubby made me smile! Wild proportions!
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jackssmirkingrevenge
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Thu Sep 16, 2021 2:53 am

iknowmy3tables wrote:
Thu Sep 09, 2021 8:03 am
There's no comparison the smaller cannon shoots with way more force
Have you quantified that force? Are you running the same pressure in both launchers?

Seems a little counter-intuitive that a valve with what I presume is faster opening time but lower flow would perform better in these circumstances.
hectmarr wrote:You have to make many weapons, because this field is long and short life
iknowmy3tables
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Thu Sep 16, 2021 6:47 am

Lol, I see what you're saying a lot more energy in the larger one used inefficiently. I'll make a video next time I visit my friend. Not a strictly controlled test but the large cannon was filled to something like 80psi the small cannon filled to a fraction of that shooting the same tennis ball we shot both vertically and got way more time in the air with the smaller cannon
iknowmy3tables
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Wed Oct 13, 2021 10:00 pm

I stopped by my friend's place made a simple test shooting shuttlecocks made from bottles at 60psi vertically
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jackssmirkingrevenge
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Thu Nov 25, 2021 9:32 am

That's pretty impressive, especially for such a short barrel and small chamber, although I wouldn't tale a shuttlecock as a representative projectile really. As it's not airtight it's basically being propelled by the air impulse and a fast-opening valve would have the advantage here irrespective of barrel length.
hectmarr wrote:You have to make many weapons, because this field is long and short life
getgray
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Wed Sep 07, 2022 8:36 pm

Anyone know how to mode a QEV in GGDT?
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