Definition
A turbofan engine in which the fan is mounted at the front of the engine, ahead of the compressor and combustion sections. The fan accelerates a large mass of air around the outside of the engine core (bypass air), producing most of the engine's thrust, while a smaller portion of air passes through the core to drive the turbines that turn the fan.
Plain English
A jet engine with a large fan at the front. The fan pushes most of the air around the outside of the engine to produce thrust, while only some of the air goes through the hot inner part of the engine.
Context Anchor
Seen in turbine engine and aircraft powerplant discussions, especially when identifying different turbofan engine layouts.
Derivation
Forward' indicates the fan's position at the front of the engine, distinguishing it from an aft-fan engine where the fan sits at the rear. The naming exists specifically to separate these two turbofan layouts.
Why Pilots Care
Forward-fan engines are the dominant design in modern aviation. Understanding that most thrust comes from the bypass air (not the hot exhaust) helps explain why these engines are quieter, more fuel-efficient, and more responsive than older pure turbojets.
Grounding Statement
If you look into the front of this type of engine, the large visible blades are the forward fan that pulls air into the engine.
Intuition Check
Forward-Fan Engine does not mean the engine only produces forward thrust. It means the fan is physically located at the front of the engine.
Example Sentence 1
The 737's CFM56 is a forward-fan engine, with the large fan visible at the front of each nacelle.
Example Sentence 2
Mechanics replaced a worn bearing in the forward-fan engine before the next scheduled flight.