I really enjoyed your thrifty approach to making the burner, especially how you used the knot in the wood to help form the cone. Your set up is very basic but you made a great burner.

Normally the mixing tube's diameter expands as the gas/air mixes and exits a larger bell. I have never seen a return on the bell creating a chamber. This chamber must choke the gas and air to thoroughly mix them. I'm inspired to build one to try out and compare with my existing burners!