Advanced technology engine
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Advanced technology engineis a turbine engine that allows different turbines to spin at different, individually optimum speeds, instead of at one speed for all. It became common in the 21st century.[1]It emerged on larger airplanes, before finding other applications.
Details
[edit]One version has three drive shafts instead of the usual one. This allows the three sets of blades to revolve at different speeds. An intermediate design is a twin-spool engine, allowing two different speeds. ATE advantages allow lower noise levels.
Examples
[edit]Rolls Royce Ultrafan
[edit]TheRolls Royce Ultrafanis the largest and most efficient engine to allow multiple turbine speeds. The turbines behind the main fan are small and allow more air to pass straight through, while a planetary gearbox "allows the main fan to spin slower and the compressors to spin faster, putting each in their optimal zones."[2]
Other geared turbofans
[edit]Geared turbofansare also used in the following engines, some still in development:Garrett TFE731,Lycoming ALF 502/LF 507,Pratt & Whitney PW1000G,Turbomeca Astafan,andTurbomeca Aspin,andAviadvigatelPD-18R.
Astro Mechanica
[edit]In 2024 this startup announced its TurboElectric Adaptive Engine. Instead of a fixed gearbox, it uses an electric motor to turn the turbine(s) behind the fan at an ideal speed for each phase of flight. The company claimed it would support efficient take-off, subsonic, supersonic, and hypersonic speeds. The electric motor is powered by a generator in turn powered by a turbine. The approach relies on the improvedpower densityof novel electric motors such as yokeless dual-rotoraxial flux motorsthat offer far more kw/kg than conventional designs that were too heavy for such an application.[3]
Air flows in through a turbogenerator to produce electric power to power an electric motor. The electric motor adaptively controls the propulsion unit, allowing it to behave like a turbofan, turbojet, or ramjet depending on airspeed. In effect the engine can operate at any point along the specific impulse (Isp) curve - high Isp at low speed or low Isp at high speed.[4][3][5]
It is in some respects similar toturbo-electric marine enginesthat allow propellers to turn at a different speed than the steam turbines that power them.
See also
[edit]References
[edit]- ^Wragg, David W. (1973).A Dictionary of Aviation(first ed.). Osprey. p. 4.ISBN9780850451634.
- ^"World's largest and most efficient aircraft engine aces first tests".New Atlas.2023-05-22.Retrieved2023-09-24.
- ^abKeil, Christian (February 28, 2024)."Interview with Ian Brooke".x.
- ^McCormick, Packy (April 1, 2024)."Astro Mechanica".notboring.co.Retrieved2024-04-02.
- ^Côté, Andrew (February 28, 2024)."Astro Mechanica".x.RetrievedApril 2,2024.