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quiteness

A place to ask general spud cannon related questions.
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quiteness

Unread postAuthor: jon_89 » Thu Apr 03, 2008 1:09 am

What makes a cannon quite? I ask because there have been alot of topics about silencers and since they are illegal you cant quite down your gun. So what makes a pneumatic and combustion quite? Is it the ratio maybe the ammo?
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Unread postAuthor: jackssmirkingrevenge » Thu Apr 03, 2008 1:45 am

There's nothing we can do about the noise of projectile impact (though of course shooting at metal plates or sheets of glass will make things louder), what we can influence is the muzzle blast

What makes this noise is high pressure gas exiting the muzzle. The lower the pressure, the less noise it makes. This is why for a given chamber, a longer barrel will be quieter. It gives the air more space to expand in (and therefore reduce in pressure) before it exits to the atmosphere. This is essentially the principle behind silencers.

With combustions, you have the added element of hot gasses that also applies to firearms, so anything you can do to cool them (using wire mesh, liquid etc.) will cut down the pressure and therefore the noise.
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Unread postAuthor: Carlman » Thu Apr 03, 2008 2:56 am

scince i am interested aswell in making a quiet launcher, how low is too low for a ratio in terms of power loss? Like would a C:B ratio of 0.6:1 be a good trade off?

and to OP, you can use them just dont get caught :wink:
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Unread postAuthor: jackssmirkingrevenge » Thu Apr 03, 2008 3:09 am

Carlman wrote:since I am interested as well in making a quiet launcher, how low is too low for a ratio in terms of power loss? Like would a C:B ratio of 0.6:1 be a good trade off?


It depends on many things. I would suggest modelling your launcher in GGDT. Use the maximum barrel length you're willing to live with, then progressively make the chamber volume smaller and smaller until the power reaches the limit of your expectations.
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Unread postAuthor: Carlman » Thu Apr 03, 2008 3:14 am

yea thats what ive been doing thanks jack
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