Today, the newly completed Supercannon II achieved a range of about 73 feet.

Videos, pictures, and more information to come soon...

WOW! That's incredible...can't wait for more info. I bet that thing is amazing to shoot. Great job!

I was meaning to post this at the other forums, but decided SM didn't have that much activity.

Congratulations! I've seen the pictures and that thing is a beast! I know it uses a piston system, one quick question: Was the piston located behind the water in a seperate chamber from the air, seperated by a ball valve, or was the air filled directly behind the piston. If the latter was the case, then good job on the piston seal! I heard you ordered it from McMaster which is probably a good thing until we get good enough at crafting our own pistons.

Soak On

The piston and water were in the same chamber.

I wouldn't even bother trying to build your own piston. These ones you can order simply will be better, cheaper, and less work. I ordered two, but I'm thinking I should have ordered one.

Here's some more images: http://www.sscentral.org/images/supercannon/

I apologize in advance for the size of the files. Not much time was available to resize and recompress. When I post that link at the other forums, I'll definitely resize and recompress the images.

You should get a good idea what the piston is made from in the pictures. How it was assembled into the pipe however is more tedious than you would believe. I'll explain in a later reply.

Yes, I knew that the piston sat directly behind the water, my question (could have been worded better), was where the air sat. Was it filled directly behind the piston, or did it reside in a second chamber seperated by a ball ball valve? I'm guessing you used the first method because you bought a piston instead of making your own.

Nice pics, by the way, very impressive. I'm just glad you aren't bringing it to the regional war. :unsure:

Soak On

The air sat directly behind the piston. I didn't even consider the other design you mentioned. Before I feared seal problems to the point where I avoided pistons even though I knew they were better (Supercannon I). I think that just made me waste 9 months and a lot of money. Luckily no one else will have that problem from now on.

If you want to make something similar, I ordered two of part number 9411K28 from McMaster-Carr. They have these seals in a variety of different sizes. I'm considering buying some for some other projects of mine, but first I'll need to get some money. ;)