Coaxial Piston Cannon
Posted: Wed Sep 05, 2007 12:56 am
I made this cannon recently, as more of a prototype for a larger version.
The chamber is about 75mm diameter(internal) and the barrel is 25mm.
Chamber length is about 800mm and the barrel 1300mm.
I take it up to 110psi usually.
Constructed mainly out of pressure rated PVC pipe, and black "Hanson" pipe fittings for the exhaust and filling area.
I made some darts to shoot out of it, these consisted of a short length of wooden dowel with a bolt in one end for weight, then a smaller diameter length attached to the other end for stability, they work extremely well, flying nice and straight.
Checking with google earth flight distance is round 270m.
Did make one cock-up though. While assembling the reducer fittings, one of them glued in at an angle, meaning the barrel points at an angle now, oh well still works. My mistake, will take more care next time huh.
Keep reading about "bumpers" behind the piston on many posts, this has no such thing, it just slams into the edge of the reducer fitting that screws into the back. The compressed air coming in when filling it up then pushes it back up against the barrel. Hasn't suffed any damage at all, is this normal?
First Post.
The chamber is about 75mm diameter(internal) and the barrel is 25mm.
Chamber length is about 800mm and the barrel 1300mm.
I take it up to 110psi usually.
Constructed mainly out of pressure rated PVC pipe, and black "Hanson" pipe fittings for the exhaust and filling area.
I made some darts to shoot out of it, these consisted of a short length of wooden dowel with a bolt in one end for weight, then a smaller diameter length attached to the other end for stability, they work extremely well, flying nice and straight.
Checking with google earth flight distance is round 270m.
Did make one cock-up though. While assembling the reducer fittings, one of them glued in at an angle, meaning the barrel points at an angle now, oh well still works. My mistake, will take more care next time huh.
Keep reading about "bumpers" behind the piston on many posts, this has no such thing, it just slams into the edge of the reducer fitting that screws into the back. The compressed air coming in when filling it up then pushes it back up against the barrel. Hasn't suffed any damage at all, is this normal?
First Post.
Shame about the bent barrel but the damage shots speak for themselves, if it works it works 
).