Thanks for the info and quick reply!
I did mean rocket mass heater, dunno why I said rocket stove.
I'm checking out the site and have done much research already. From what I understand as long as the burn chamber and exhaust are roughly the same diameter with few interruptions in exhaust flow, it technically should work. Allowing for thermal expansion too of course.
I have a plan made to make it relatively inexpensive, lightweight, space saving and something that's beautiful.
I'm going to try the design a few times before I cement it all in and make sure its working, I will keep this updated with pics as I go and if it works I'll do up a plan to share.
I've been in the construction industry for almost 12 years now so I'm fairly confident I can build it, it's just making sure it will work is the issue.