rocket cook stove fuel capacity

I've been playing around with a pile of bricks making a rocket type cook stove.  Just a little pile of bricks on the ground.  It works, but I'm getting much more smoke than I anticipated.  and I have a concern about the amount of fuel that can be fed into this without having to clean it out.  I put a cast iron pot of beans on and got it to boiling then let it die out.  But the firebox is full of ash.  If I had tried to cook those beans on a continuous fire, I would have had to clean it while it is in operation.   Any different experiences?   What to do?  Grin and bare it?

How tall is it? I think you'll get less smoke if it's at least a couple feet tall and fairly airtight, with convection driving stronger airflow.

The amount of ash might be due to the variety of wood, and fuel with a lower proportion of minerals will perform better. Or if there's charcoal left, faster airflow will again mean more-complete combustion.

About 12 inches or so.  Not airtight as this is just experimental.  I agree, I built it a little higher by stacking the top layer on edge, and then I extended the fire chamber the length of a brick.  I'll have to go try and salvage more brick.
I'm burning bois d'arc, hackberry and honey locust.  All are supposed to be good wood.  I started pulling some of the ash out and used larger wood and allowed coals to build up.  The coals cook as well as the fire.