Office of Steam Forum for Model & Toy Steam Gas & Hot Air Engines

Jim, 14.7 psi is standard atmospheric pressure at sea level where you're at. The flame lickers work by creating a partial vacuum via the rapid cooling of thin hot air (hot air is much thinner, less dense, than cool or cold air), thus creating a partial vacuum, and do note that "partial", in that it is essentially impossible to create a true "total" vacuum here on earth, though space is extremely close and so qualifies in that regard ... but I digress. It is unlikely that a flame licker is producing even a half of a true vacuum, probably more like 1/3 or 1/4 would be doing good, so you are actually operating at less than 7 psi and more probably something like 3-4 psi. Thus very little actual power available with this type of atmospheric engine.

Hope that helps.