SpudFiles

I'm doing a science project for school using a pneumatic launcher. I will be using different length barrels to see what length effectively launches a tennis ball farther. My idea is to use 4' long 3" sch40 pvc for the air chamber, and reduce that to 2 1/2" and attach a ball valve on to that. To the ball valve, I will attach threads, and thread the barrels into that, so I can change the barrel length easy. I figure I'll charge it up to 100 psi, is that too much? My ideas for barrel lengths are a 3 foot barrel, and a 6 foot barrel. Any Ideas to make it better?

I would suggest not to use a ball valve, the opening time is too inconsistent to be used for a science project.
Instead you could use a sprinkler valve, or a piston valve if you have the skills to build one.

i would sugggest a coaxal marble gun for a science project it would be very consistant

dart guy wrote:i would sugggest a coaxal marble gun for a science project it would be very consistant

Why's that?

I would suggest a coaxial marble gun for a science project, it would be very consistent.

Maybe you should build one to demonstrate it

If you had read my other topic you would know I am gonna build one so you people will stop with the complaints.jrrwd i thought it would oppen at the same rate every time.also marbles are smaller than tenisballs, it could be fun later.

dart guy wrote:If you had read my other topic you would know I am gonna build one so you people will stop with the complaints.jrrwd i thought it would oppen at the same rate every time.also marbles are smaller than tenisballs, it could be fun later.

Nobody is complaining about you or my PM Inbox would be hearing about it! We are just wanting to see your build skills. :newb:

How would I modify a sprinkler valve? I've google'd it, and still don't really understand. And since I'm using a 3 inch tank, and a 2 1/2 inch barrel, and the sprinkler valve is 1 inch, would I just reduce it, put the valve in, and up it to 2 1/2 again?

micah16858 wrote:How would I modify a sprinkler valve?

http://www.spudfiles.com/pneumatic-cann ... 16786.html



And since I'm using a 3 inch tank, and a 2 1/2 inch barrel, and the sprinkler valve is 1 inch, would I just reduce it, put the valve in, and up it to 2 1/2 again?

Sounds crazy enough to work. Sometimes it actually IS "Just that easy".

jrrdw says to DG... wrote:Nobody is complaining about you ....

Does shaking my head and muttering to myself count?

Does shaking my head and muttering to myself count?

Only counts if it shows up in a mods inbox...

I made a piston valve design. It's a barrel sealing type, with the air tank under the barrel. The air tank is a 4 1/2' long 3" pvc, and the barrel is 2 1/2" pvc. I used a 2" Tee for the piston housing, with the air tank coming from the bottom. The piston is made up from a 1 1/2" plastic coupling, and a cap with a flat top inside of it. For the sealing face I used a rubber washer, with a smaller washer between the bolt head and it. I drilled a hole through the cap and bolted the sealing face and put a lock nut on the end of the bolt. I used a 2" cap for the back of the piston housing, and drilled 2 holes and put a 1/8" fill valve, like on a bicycle, and in the other hole I put a 1/8" needle valve that twists open. I'll try and upload some pics later.