// PROPULSION SYSTEMS AND ENGINE TECHNOLOGY TERM
Geared Turbofan
A geared turbofan is a type of modern jet engine that uses a gearbox to allow the large fan at the front to spin slower than the turbine inside. This makes the engine significantly more fuel-efficient and quieter than conventional turbofans.
TECHNICAL DEFINITION
A geared turbofan (GTF) is a high-bypass ratio aircraft engine architecture that incorporates a fan drive gear system (FDGS) to decouple the rotational speed of the fan from the low-pressure spool (compressor and turbine). This allows the large-diameter fan to rotate at a slower, optimal speed while the low-pressure turbine rotates much faster, maximizing propulsive efficiency, reducing fuel burn, and lowering acoustic signatures.
BACKGROUND
A turbofan or fanjet is a type of airbreathing jet engine that is widely used in aircraft propulsion. The word "turbofan" is a combination of references to the preceding generation engine technology of the turbojet and the additional fan stage. It consists of a gas turbine engine which adds kinetic energy to the air passing through it by burning fuel, and a ducted fan powered by energy from the gas turbine to force air rearwards. Whereas all the air taken in by a turbojet passes through the combustion chamber and turbines, in a turbofan some of the air entering the nacelle bypasses these components. A turbofan can be thought of as a turbojet being used to drive a ducted fan, with both of these contributing to the thrust.
READ MORE ON WIKIPEDIASYNONYMS & ALIASES
- GTF
- fan drive gear system
- geared-fan engine
- reduction-gear turbofan
- variable-speed fan drive
USAGE NOTE
This term is central to discussions on next-generation commercial airliners, highlighting the trade-off between the gearbox's mechanical complexity and its significant performance benefits.
DEVELOPERS
Organizations developing technology related to Geared Turbofan.
A subsidiary of RTX Corporation, Pratt & Whitney is the pioneer and leading manufacturer of geared turbofan engines with its PW1000G family, marketed as the PurePower engine. These engines power aircraft like the Airbus A320neo family, Airbus A220, and Embraer E-Jets E2.
A major aerospace engine manufacturer developing the next generation of geared turbofan technology through its UltraFan demonstrator engine, which features a power gearbox and is designed to be the world's largest and most efficient aero-engine.
A key German aerospace manufacturer and a major partner in Pratt & Whitney's Geared Turbofan (GTF) program. MTU develops, manufactures, and maintains critical components for the PW1000G engine family, including the high-speed low-pressure turbine.
While its joint venture CFM International's LEAP engine is not geared, Safran has independently researched geared architectures for future engines. Their work on demonstrators like U-DIEM and the new RISE program with GE explores technologies enabled by gearing.
A GE Aerospace business based in Italy, specializing in aviation propulsion components and systems. Avio Aero is a key developer and manufacturer of power transmission systems and gearboxes, including the main power gearbox for the Rolls-Royce UltraFan engine demonstrator.
As part of its Advanced Air Vehicles Program, NASA conducts foundational research and testing on advanced engine concepts to improve efficiency and reduce noise. The center has been instrumental in testing components and validating concepts related to geared turbofan technology.
Another subsidiary of RTX Corporation, Collins Aerospace develops and supplies critical systems for GTF engines, most notably the entire nacelle system for the Pratt & Whitney PW1000G engines used on the A320neo.