Hi Scott, you’re only going to be wasting your time if you think your little
rocket stove is going to be perfect on the first try. Of
course there are some basics to follow just to make it work but there’s always room for improvement through experimenting and finding out firsthand what works and what doesn’t. Playing with soft red clay bricks is a great way to try various configurations until you find one that works for you.
One of the basics to follow is to keep The cross-sectional area the same throughout the core. The
feed tube however can be made somewhat smaller if you prefer.
Hope this helps as a starting point.