"Suck, squeeze, bang, blow"
Rolls-Royce says its Trent XWB is one of the most fuel-efficient jet engines in the world. The "XWB" stands for "extra wide body," and you can see why. Up close, this thing is huge. The fan blades consist of titanium to improve weight specifications and "fuel burn performance." Engineers describe the way it works as "suck, squeeze, bang, and blow" - all technical terms of course.