An aircraft gas turbine engine includes a fan system having a reverse traveling wave first flap mode, Fan RTW, and including a fan upstream of the engine core; a fan shaft; and a front engine structure to support the shaft and having a front engine structure nodding mode FSN including two modes at similar, but unequal, natural frequencies in orthogonal directions; and a gearbox. The engine includes a gearbox, and a gearbox output shaft to couple output of the gearbox to the fan shaft. An LP rotor system including the fan system and the gearbox output shaft has a first reverse whirl rotor dynamic mode, Rotor RW. A frequency margin of:⁢the⁢⁢frequency⁢⁢difference⁢⁢between⁢⁢mode⁢⁢⁢⁢FSN⁢⁢and⁢⁢the⁢⁢highest⁢⁢frequency⁢⁢of⁢⁢either⁢⁢⁢⁢synchronous⁢⁢Fan⁢⁢RTW⁢⁢or⁢⁢synchronous⁢⁢Rotor⁢⁢RW⁢the⁢⁢lowest⁢⁢natural⁢⁢frequency⁢⁢of⁢⁢⁢⁢the⁢⁢front⁢⁢structure⁢⁢nodding⁢⁢pair⁢⁢of⁢⁢modesis in the range from 5 to 50%.


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    Title :

    Aircraft gas turbine engine with improved response to rotor unbalance


    Contributors:

    Publication date :

    2022-06-07


    Type of media :

    Patent


    Type of material :

    Electronic Resource


    Language :

    English


    Classification :

    IPC:    F02C Gasturbinenanlagen , GAS-TURBINE PLANTS / B64D Ausrüstung für Flugzeuge , EQUIPMENT FOR FITTING IN OR TO AIRCRAFT / F02K JET-PROPULSION PLANTS , Strahltriebwerke / F04D Strömungsarbeitsmaschinen , NON-POSITIVE-DISPLACEMENT PUMPS



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