Great to see responses from so many of you. I would say it this way, "I have installed a Leitinger Nozzle in the Gilmore Simple Fire. As has already been mentioned, I too think that the mass of metal absorbing and radiating the heat away from the holes as well as the velocity pushing the glowing charcoal away from the pipe are what makes this work so well.
I have had more heat being pushed into the top of the gasifier wtih this nozzle. I’m thinking that is partly due to the increased velocity. Koen calculated that I needed a 1 inch nozzle, which divided by four became about 1/2 inch each. Due to the suggestion that the hole sizes should be stepped up in size, with the smallest being at the stopped end of the pipe, my sizes started at 3/8 inch and went up to 1/2. So, I actually had less area than calculated.
I may have made a mistake, but while the nozzle was out, I decided to drill the holes larger in the hopes of keeping the reaction zone lower in the barrel allowing me to run longer before overheating. That may result in deterioration of the nozzle pipe—we shall see. The new holes sizes are 7/16, 1/2, 9/16, and 5/8 inch. I wish I had just made them all 1/2 inch, but it is done now. That 5/8 inch hole looks BIG–maybe too big.
In my next “long distance run” with the modified nozzle I will be using premium fuel in the car for the first time (oak charcoal)–also with the hope of extending the run time and distance.
My son and I demonstrated charcoal lawn mower at a local tractor and engine show last weekend. Before the end of the day we started up the Corolla and drove it around the grounds on charcoal for a while. I took my camera, but forgot to take pictures–sorry. One guy looked at me like, “You expect me to believe that you are running an engine on charcoal?” I think everyone enjoyed the show. SWEM.