ELI5: Explain Like I'm 5

Variable cycle engine

A variable cycle engine is a type of jet engine that can change the way it works depending on the situation. It works by using different parts of the engine to create thrust, or push the plane forward. By changing the way the engine works, it can be more efficient, meaning it uses less fuel in a flight and makes the plane quieter. It can change between different settings whenever the pilot needs more power or wants to save fuel.