First pneumatic (correct my spelling)

Just build a cannon and want to show it off? Post it in here.

Postby fullmetaljacket » Sun Feb 11, 2007 10:16 pm

When a cannon is loud, it's basically wasted air - compressed air which leaves the muzzle without having expended all its energy.

This is why, for example, a longer barrel is quieter - the air has more space to expand and use up its energy before being released into the atmosphere.

What I'm trying to convey is, the more efficient your launcher is, it will allow you to do more with less (or in this case, the same performance for a lower initial pressure) and will therefore make less noise.
fullmetaljacket
 
Posts: 1684
Joined: Mon Jun 14, 2004 1:33 pm
 

Postby gtfan6 » Sun Feb 11, 2007 10:20 pm

hey corey(garrett) just wanted to say hey and thx for building that potato gun 4 me today!!! p.s. nice gun
gtfan6
 
Posts: 2
Joined: Sun Feb 11, 2007 10:16 pm
Location: USA
 

Postby Arborman495 » Sun Feb 11, 2007 10:21 pm

O....
I will widen that hole and do whatever else I can. Thanks FMJ

Holy Crap! well done Garett. Was it LOUD??!!!????
Did you parents freak out? Sweet!!

We have got to paint it and put up some pictures on here. That is a BIG gun. Even by these people's standards(maybe). :D

Be careful with it. dont ever shoot it with the cap off.

You are on you way, Garret

Triple freakin sparks[:p] p.s. try to spell right and use caps or else the dog will come and bite you!!
Arborman495
 
Posts: 86
Joined: Sun Dec 10, 2006 6:39 pm
Location: USA
 

Postby gtfan6 » Mon Feb 12, 2007 8:28 am

Louder than anything that i ever heard!!! My mom said that the cops may get called. It blew that paper towel that we left in there to absolute bits!

Got the static guard and it works like a dream!!! Only thing is that we were having trouble getting the spark to ignite[:(!]. When it did we got great results8)We lost one of the little rubber balls and never heard it land. When Andrew finally got it straight it probably had a 7 to 8 second hang time. Well sorry that i was just estimating(just kidding) The wadding is pretty tight and let's just say that the wadding for the ball that dissapeared landed on the roof. Also muzzle flash was cool too and it wasn't as loud when we put everything in it.8)8)8)8)8)8)8) So will I see you tonight at church?
gtfan6
 
Posts: 2
Joined: Sun Feb 11, 2007 10:16 pm
Location: USA
 

Sponsored

Sponsor
 
 

Postby Arborman495 » Mon Feb 12, 2007 9:29 am

Sweet
Arborman495
 
Posts: 86
Joined: Sun Dec 10, 2006 6:39 pm
Location: USA
 

Postby brian the brain » Mon Feb 12, 2007 4:32 pm

I dissagree with the wasted power thing.A long barrel wich still makes a big bang is better powerwise.The projectile gets maximum push that way.

When it 's silent it uses up all the power .That way it is more energy efficient,but not more powerful.There is a difference.
brian the brain
 
Posts: 106
Joined: Thu Mar 23, 2006 5:31 am
 

Postby Arborman495 » Mon Feb 12, 2007 5:02 pm

Well, there always is projectile friction to take into account. The psi decreaces as the shot moves along the barrel. You have to have the projectile exit the barrel a bit before the friction equals the psi. Or you can do my method and make a gun that is loud and use a silencer.

The noise is (most of the time) half the fun
Arborman495
 
Posts: 86
Joined: Sun Dec 10, 2006 6:39 pm
Location: USA
 

Postby fullmetaljacket » Tue Feb 13, 2007 3:31 am

<blockquote id="quote"><font size="1" face="tahoma,verdana,arial" id="quote">quote:<hr height="1" noshade id="quote">Originally posted by brian the brain
[br]I dissagree with the wasted power thing.A long barrel wich still makes a big bang is better powerwise.The projectile gets maximum push that way.<hr height="1" noshade id="quote"></font id="quote"></blockquote id="quote">

If your long barrel is making a big bang that means you can increase the barrel length and it will be even more powerful.

Take firearms for example, the M4 carbine is louder and makes a bigger flash than its longer barreled M16 counterpart, but the latter has a higher muzzle velocity.
fullmetaljacket
 
Posts: 1684
Joined: Mon Jun 14, 2004 1:33 pm
 

Postby brian the brain » Tue Feb 13, 2007 4:09 pm

True.But imagine your increased barrel length WITH the loud bang and you'll see what I mean.
Just a matter of taste I guess.Think of this dilemma from the projectiles point of view.
With my way, the projectile will get maximum push.
brian the brain
 
Posts: 106
Joined: Thu Mar 23, 2006 5:31 am
 

Postby fullmetaljacket » Wed Feb 14, 2007 9:12 am

If you´re limited to a barrel of a certain length, then yes, louder bang = wasted air and therefore maximum power.

Once you´re reached a limit of chamber pressure and volume and valve efficiency however, the longer and therefore the quiter barrel will give you the greater power.
fullmetaljacket
 
Posts: 1684
Joined: Mon Jun 14, 2004 1:33 pm
 
 
Previous

Return to Finished Cannons

cron