{{Short description|Turbofan engine component}} {{About|part of a turbofan jet engine|the video game–related package of additional content|fan disc}} {{More citations needed|date=December 2009}} {{Use dmy dates|date=May 2014}} {{Use American English|date=May 2014}} thumb|Diagram of a fan disk thumb|Fan disk assembly diagram, showing one blade and attachment hardware thumb|left|Cross section of fan disk thumb|Failed fan disk recovered from the center engine of UAL 232.
A '''fan disk''' is the central hub of a fan in a turbofan engine. Fan blades are attached to the fan disk, which is rotated by a shaft driven by a gas turbine.<ref>{{cite book | last = Khurana | first = K. C. | title = Aviation management : global perspectives |page=60 | publisher = Global India Publications | location = New Delhi | year = 2009 | isbn = 9789380228396 }}</ref> In modern passenger aircraft, most of the propulsive thrust comes from fans, which are driven by gas turbines. A single stage fan was developed to produce high thrust and act as a multi-bladed propeller. Fan disks are attached to a shaft that is driven by a multistage Low Pressure Turbine (LPT) to reduce mechanical stress.<ref>{{Cite book|title=The Development of Jet and Turbine Aero Engines|last=Gunston|first=Bill|publisher=PSL|year=2006|isbn=0-7509-4477-3}}</ref>
Air enters the front of an engine, where a fan increases the pressure by rotating within a duct. Most of the pressurized air is exhausted through the rear of the engine, where it expands and its velocity increases.
Fan disks are large and heavy. The one shown in the photo is over 31 inches (1.2 m) in diameter, and rotates up to 3800 rotations per minute (RPM).<ref>{{cite web |title=General Electric CF6-6 Turbofan Engine, Cutaway |publisher=Smithsonian Institution |url=https://airandspace.si.edu/collection-objects/general-electric-cf6-6-turbofan-engine-cutaway |access-date=October 28, 2018 |archive-date=29 October 2018 |archive-url=https://web.archive.org/web/20181029071548/https://airandspace.si.edu/collection-objects/general-electric-cf6-6-turbofan-engine-cutaway |url-status=dead }}</ref> Fan disks must withstand the centrifugal force of the attached fan blades. Because of their size and weight, a failed fan disk can severely damage an aircraft, as happened with United Airlines Flight 232 in 1989.<ref>{{cite web |title=AAR-90-06, Aircraft Accident Report, United Airlines Flight 232 McDonnell Douglas DC-10 Sioux Gateway Airport, Sioux City, Iowa |date=July 19, 1989 |publisher=National Transportation Safety Board |url=https://www.ntsb.gov/investigations/AccidentReports/Reports/AAR-90-06.pdf |access-date=October 28, 2018}}</ref> While operating there is increased aerodynamic loading on the fan disk while the fan blade tips are traveling faster than sound.<ref>{{Cite book|title=The Design of High-Efficiency Turbomachinery and Gas Turbines|last=Wilson|first=David|publisher=The MIT Press|year=2014|isbn=9780262526685}}</ref> A fan blade weighing 15-lbs can experience upwards of 60 tons of centrifugal force.<ref>{{Cite book|title=Mechanics and Thermodynamics of Propulsion|last=Hill|first=Phillip|publisher=Addison-Wesley Publishing Company, Inc|year=1992|isbn=0201146592}}</ref>
Fan disks are usually made of a titanium alloy, which is strong, light weight, and resistant to corrosion.
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==See also== * United Airlines Flight 232, which crashed after the fan disc in its number two engine shattered and damaged all hydraulic systems
==References== {{reflist}} Muhammad Adnan, Liu Shujiel; FEA Analysis and Fatigue Life Prediction of Aircraft Turbine Disk; North American Academic Research, 4(4) 10-19, Apr 2021, https://doi.org/10.5281/zenodo.4670446
<ref>Muhammad Adnan, Liu Shujiel; FEA Analysis and Fatigue Life Prediction of Aircraft Turbine Disk; North American Academic Research, 4(4) 10-19, Apr 2021, https://doi.org/10.5281/zenodo.4670446</ref>
{{DEFAULTSORT:Fan Disk}} Category:Aircraft propulsion components
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