SpudFiles

the cannon i'm building has a female endcap and a male bushing on the back of the chamber. i would like to mount the fan in the male bushing but i'd be a little worried about the combustion forcing it backwards and breaking it when it hits the end cap. i also want the fan to be able to be removed without too much trouble for cleaning and maintainance inside the chamber. i could machine something special to hold it there, but before i bother with that, i was wondering if anyone might have a simpler solution. being a machinist i can design and make nearly anything i put my mind to but sometimes there is an easy answer right in front of my face that i don't see.

umm if you want it to be able to be removed i would go with screws just make sure it does not move and it should not break the pressure will not last long anough

I just used a couple dabs of glue to hold mine in place, and its used in a 2x hybrid with no problems. However, in another experiment i used a fan with a pure O2 and propane mix and the fan shattered every single time, first shot. So if you are using air and fuel, the fan should be fine with a few dabs of a good rubber cement glue.

if you are doing an over under design id put a tee where the elbow of the combustion chamber slap on a female adapter and put a check valve

kind of off topic, but on the site that you just provided a link to, has anyone looked at the rifled barrels page?
where it says
"The only pic of the hallowed rifling machine"
doesn't look so special to me. just looks like an old toolroom lathe with the pipe clamped to the cross-slide and boring tool held in the chuck. just saying, they talk it up like it is something special. i have 2 lathes that are probably just like it, in addition to my 5 CNC lathes (looking to buy a slightly bigger CNC soon too).