Have not posted progress in a while, other projects in the works. Wanted to show my detail on the hot tube burner. Rather than trying to drill a very small gas jet hole, I use a piece of 1/16" OD hobby brass tube which projects into the fuel/air tube. This has the effect of drawing in air via a Venturi effect and is less prone to breeze effects. The tube is progressively crimped down at the gas pressure being used to adjust the fuel air mix. If you go too far, simply uncrimp it a bit. This is from my other working model of the same engine and so appears used. From light off, this heats the tube to red heat in 2-3 mins. My hot tubes on the models are 1/4" SS tube with TIG welded ends. I also use this on all my larger full sized engines. For the purists, this may be out of bounds, but for having a reliable draft insensitive burner, I'm happy with it.