Slight mod to existing diaphragm cannons

[Big GEOFF]

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.

[SpudStuff]

too small mahe it bigger

[sergeantspud2]

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?

[Big GEOFF]

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?

[boilingleadbath]

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.