Flame Eater Engine: also called a vacuum engine- operates by opening a valve during the piston intake stroke to pull in a bit of burning gas from the flame- the valve closes and the trapped hot gas expands pushing the piston. The exhaust stroke then has the gas cool, contract, and get pushed out the same valve right before the process repeats. Slow motion captures the intake of the flame through the valve/mouth at the cylinder head which gives the appearance that flame is being chewed- hence the