I know there are programs out there for the calculations, but I need the actual data and each step in the calculations for a physics project. Does anyone know how this would work with a pneumatic cannon using a piston valve, in terms of figuring out the distance it can fire with given angles and ...

How exactly could I modify that to handle such a large cannon though? Are there any guides?

I'm looking to build a stand for my cannon, but only have like an hour or two of time to put it together. My cannon is like 6.5 feet long and quite powerful with a 3' long chamber, with a coaxial design using a piston valve.

Can I build some type of stand that can adjust the angle easily?

Thanks

Ok so now that issue might be fixed, but another has arisen.

When the cannon was tested, the potato simply slowly went though the barrel and dropped on the floor. Water vapour could be seen coming out of the barrel, but it didn't seem like there was much pressure based on the movement of the ...

Would you mind me asking if you have a home depot link for those rubber sheets? I can't seem to find them online, and when I asked in store they told me there was pretty much no rubber I could use.

As for the washers, would you put those on top of the rubber, or below usually? My piston center and ...

Ok so now everything is solved, except for some leaking through the barrel still. I guess the piston isn't getting a proper seal. The face of the piston is a metal plate, with a piece of rubber (cheap stuff tho) bolted on top. The barrel was never cut, but maybe when it was glued it wasn't 100 ...

Is there any way I can get 4" neoprene from any of those big stores? I realized with the coax design, I have nothing holding the barrel in the center of the chamber properly...should I maybe put screws in to hold it down and make sure it doesn't move? I'm curious what people normally do.

But yea ...

I finished this cannon, but there was one issue. Since I did a coax design, I sanded out my 4" to 2" reducer coupling so the barrel could go straight through. I sanded it a bit too much though, and the fit was loose. When I filled it up with air, there was space between the barrel and the coupling ...

Yea we'll get the piston thing figured out this weekend, but one more question, when my piston is touching the back of the chamber, how much space should be between it and the barrel? Since that's a stationary length, I don't want to mess it up.

At the back of the chamber I have a coupling and male ...

lol I'm confusing myself, and everyone else a bit too much it seems. I'm back to the coax design, and have all the parts ready to build it other than the piston. I picked up a 3inch coupling, but it doesn't fit within the 4in barrel (using abs pipe) so it seems that idea for a piston won't work ...

I'm going more for precision than anything. But I'll look into that still.

Also, thinking about the coaxial one a bit more, would 3' of a 4in pipe be good enough for the chamber, or does the barrel need something a bit longer at still at least?

In the chamber construction section of the following ...

Alright thanks for the help guys! After looking up some costs though, doesn't look like the coaxial version is my best bet if I want to build a piston valve cannon, as the 4" pipe is $50 alone for a 6 foot length and I'm trying to keep the whole thing around $50-60 lol.

I'm thinking of doing a ...

So it should be able to move an inch backwards / forwards with a 4in barrel, in a coaxial design cannon? Also, what stops the potato from going to far into the barrel? Since it's loaded before filling the cannon with air for safety, couldn't it get pushed down to far and have pieces go into the ...

I'd like to make it 4" since I'll be putting the 2" barrel into the chamber already.

Basically, I'm aiming to make something like this - http://www.xinventions.com/main/spud/pac5.htm

Should I make the piston out of wood as in that video above, or is there a better option? And yea, how does the ...

It's for a grade 11 physics ISU. And I don't want to restrict the budget too much, having to modify the cannon (even slightly) for every single shot would probably make it considered a lower end compared to the rest. If anything, I would just use a valve in between chamber and barrel but would ...