FAA Aviation Mechanic Powerplant (AMP)Turbine EnginesEasy
Which type of gas turbine engine uses a large-diameter fan at the front of the engine to bypass a large portion of incoming air around the engine core, with most of the thrust produced by the bypassed air rather than the core exhaust gases?
- ATurboprop
- BTurbojet
- CTurboshaft
- DTurbofan
Show answer & explanationAnswer & explanation
Correct answer: D. Turbofan
A turbofan engine uses a large front fan to accelerate a large mass of bypass air, which produces most of the thrust, improving fuel efficiency and reducing noise compared to a pure turbojet.
Why the other options are wrong
- A. A turboprop uses a reduction-geared propeller for thrust, not a ducted fan.
- B. A turbojet uses only core exhaust gases for thrust, with no bypass fan.
- C. A turboshaft delivers power through a shaft, not thrust from a fan or jet exhaust.
Turbofan Engine
A gas turbine engine with a large front fan that bypasses a portion of intake air around the engine core, generating most thrust from the bypass airflow.
- Improves fuel efficiency over turbojets
- Bypass ratio compares bypass air to core air
- Common on commercial airliners
Memory trick: 'Jets Fan Props Shafts' - Turbojet, Turbofan, Turboprop, Turboshaft