SpudFiles

I had a few air cylinders lying around the basement from my dads business and i thought that i could incorporate it into a cannon design. I picked up an air cylinder that had a large bore (alot of power) but small throw and i thought i could use it to open and close a valve and i came up with this design

the air cylinder pushes the diaphragm against the barrel sealing the chamber off and pulls away releasing all of the air. I modified the air cylinder so that it moves in and out very fast. Im building it currently and will have pictures posted within the next few days.

too small mahe it bigger

how did you get the seal between the air cylinder's ram and the cleanout cap or have you not got to that part yet?

Well i cut off the square end of the cleanout cap and had to dremel out a little bit of the square hole to fit the cylinder in because theres a circular disk that is on the end of the cylinder. For now i just put alot of pressure rated silicone in between the cylinder and cleanout cap. also, the diaphragm in the pictures is just a mock up. I still need to make a real one, however, i have no experience with these types of cannons so i dont know what material i will use for the diaphragm...any recomendations?

Do you have a chronometer? I'd be interested in calculating the opening time of this device, by assuming a certain CV and adjusting the opening time of a generic valve in the GGDT.