Sinclair, The chuffs change by applying slight throttle and go in and out of sync due to the closeness of the magnets. I am going to add 2 more magnets. It is almost spot on with the various recordings I've heard. ERR does make a recording with the air pumps currently and I did not care for the articulated sound chip, no horn.
Brandy this has two seuthe units which I'm going to modify with my own fan unit and injection tubes. Seuthe units work completely different than fan smoke units.
I appreciate the kind comments, I'm about 40% done. Lots more detail to come. My production type solder gun shorted out and blew up in my hand a day ago and I'm trying to find another one.
It may be time to buy an induction unit.
