Interesting design, I like it. Lends to some good ideas. Let us know how it turns out.

All I'm saying is that there has to be a measurable/ noticeable difference in the performance of the cannon due to shape. Just like technician said smooth vs 90 degree angles. I think its at least worth exploring. I was thinking of the shape of a co2 cartridge, round on one end and gently tapered on...

No harm or foul just trying to get some new ideas for my first build and figured this would be an interesting topic to discuss considering we are striving for flow and power. My have to try a few things I have on my idea list.

So does the fan inside the chamber create an obstruction of flow? I understand the purpose of having one, just curious if it causes a disturbance or if it's not considered a factor. What about having a bowled endcap?

Ok, scratch the 83" barrel. Going with 62" x 2" on a 24" x 4" chamber. still end up with a 1.55 ratio, roughly.

Directing the charge is what I was going for in theory. In combustion engines the transition of combustion is a factor in making power ie how fast the exhaust gasses exit directly affects the speed and force of the piston in motion as well as the force of the explosion within the chamber......so in ...

So has anyone tried to make a chamber that, internally, helps direct the charge or explosion inside the chamber?

So chamber, short and fat over long skinny, got it. I thought that the magic number for cb ratio is 1:1.5? 60 inches seems short for that ratio. Not to change subject.

Well I'm going to go with a 4" x 24" chamber and a 2" x 83" barrel which gives me a ratio of 1:1.56 for my first cannon.

What about end cap and coupler shape? How about a way to internally direct the charge?

So I'm new to this site, and it kicks a**!!!!! Getting ready to build my first ever spud cannon and I was wondering if shape of the cb matters to combustion force. This is a sad side note....I'm 33 and have never built one.