Simple: The term 'engine' is used when English units are used. The term 'motor' is used when Metric units are used. Unfortunatly, we commonly use mm when talking about the diameter of the device and inches when refering to the length. Furthermore we use pounds to describe the thrust but N-sec for the total impulse. Therefore both 'engine' and 'motor' are incorrect as we use them. The more accurate word to descride the devices is 'Whoooosh generator'. All set?Ooooh Ed,
We've had long (and sometimes sort of heated) discussions about motors vs. engines for a long time. Go ahead and search here and in the archive if you're really interested but basically while there is some disagreement as to what's "proper" most os us use the two terms pretty interchangeably (proper or not).