SpudFiles

Hi everybody, I am going to do a school project related to air cannons and a have a noob question that i didn't found with the search function. I want to do a cannon but it has to shoot only air (projectiles are not allowed) and it has to throw some aluminum cans at different distances, my question is that if I do a pneumatic air cannon but i don't put any projectiles inside, will it shoot enough air to throw the cans?
and how far have to be the cans to throw they, ie around 20 feet between the cannon and the cans, do you think the cannon will be able to throw the cans?, or 50 feet maybe
I want to do a simple pneumatic cannon, something a noob at this can do, it has not to be very powerful.
Thanks for your answers.

can you get a barrel to fit the can in it ans have the can as your projectile. Thats what i would do.

-_- wrote:can you get a barrel to fit the can in it ans have the can as your projectile. Thats what i would do.

That seems to go against the concept...

To throw a can from 20 feet (empty, I presume), you might want a somewhat large chamber, decent pressure (100+ psi), and a long, thin barrel to concentrate the pressure. A piston valve would probably work best, but if you don't want to mess with those, I would go with a modified sprinkler valve.

i dont think he wants a projectile, he wants to blow high pressure air at a can sounds like fun,lol

i bet if you built this you would get a A for sure.

jarm0591 wrote:Hi everybody, I am going to do a school project related to air cannons and a have a noob question that i didn't found with the search function. I want to do a cannon but it has to shoot only air (projectiles are not allowed) and it has to throw some aluminum cans at different distances, my question is that if I do a pneumatic air cannon but i don't put any projectiles inside, will it shoot enough air to throw the cans?
and how far have to be the cans to throw they, ie around 20 feet between the cannon and the cans, do you think the cannon will be able to throw the cans?, or 50 feet maybe
I want to do a simple pneumatic cannon, something a noob at this can do, it has not to be very powerful.
Thanks for your answers.

A well built air cannon has a very strong air blast. My 2 inch was able to toss an air impact wrench down a concrete floor from 3 feet away. I have a video online of my 1 inch tossing a plastic bucket from 3 feet away. A few empty tin cans would be no problem.

Do you have regulations limiting the air pressure tank size or other safety consideration you must comply with?

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Edit, I am considering building a vortex barrel for this cannon specificaly to do vortex rings and knock things over at a distance.

I now have a new project.. See how far away I can knock over pop cans in the driveway with a blast of air.

I know that my 1/2"x6' cannon was able to throw 4 cans 20', when they were right in front of the barrel, but it definitely wouldn't knock anything over more than a few feet away.

You could add the principle of an airzooka to it.
An airzooka is basically a drum with a hole in one end and a flexible sheet on the other.Pull back the sheet and the air comes ot the hole in a circle, wich keeps spinning.
It forms a stable blast of air than can travel quite a distance.
A good ( and visible example of a homemade version is the first vid here:



Some more:





Combine this idea with a pneumatic cannon and it might be even better!

suburban spudgunner wrote:To throw a can from 20 feet (empty, I presume), you might want a somewhat large chamber, decent pressure (100+ psi), and a long, thin barrel to concentrate the pressure.

Concentrate the pressure on what? A very small point of the can?

If you have 100psi coming out of a 20mm valve port into a long 5mm barrel you don't increase the pressure but what you have done is decrease the force as the air blast is now a thin 5mm jet instead of the larger blast from the 20mm opening and thus transfers a lot less energy to the can.

If the cannon cannot fire a projectile then you do not want to use a barrel. You may want to use a nozzle of some kind to manipulate the blast but a barrel is for acceleration of a projectile and since you can't have it in the barrel... forget the barrel.

If this is to have repeatable results you may also want some kind of holder in front of the valve port/nozzle for the can, perhaps a trough made of half a pipe or something.

Biggest chamber you can build, biggest fastest valve you can get your hands on or manufacture, and no barrel whatsoever.

obviously, he is looking for a vortex gun.. the only question is 'could it be operated pneumatically'? or in other words - does it really need a flexible sheet ??

Thanks for your answers.
I saw a video on youtube, do you think this is strong enough? or a pneumatic cannon is more powerful?

jarm0591 wrote:Thanks for your answers.
I saw a video on youtube, do you think this is strong enough? or a pneumatic cannon is more powerful?

To answer that compare the impact of that one with the muzzle blast shown above. Those blow out candles. You want to toss cans.

I think he should incorperate the vortex into a pneumatic cannon. So he can use a vortex cannon with a monstrouse piston valved cannon replacing the sheet of strechy material in the back of the gun.

@dudeman508

yeah either that or fill rapidly the other side of the flexible sheet with a piston valve... it would be good to put some vent holes there and add rubber bands that would return it back to the original position after a few seconds... who said it can't be a semi



I've seen one that used acetone to achieve the same effect.. so maybe it's not the sheet but the hole cut at the muzzle of the gun.. (uhmm you know what I am talking about right??)