US 11,725,591 B2
High power epicyclic gearbox and operation thereof
Mark Spruce, Derby (GB)
Assigned to ROLLS-ROYCE plc, London (GB)
Filed by ROLLS-ROYCE plc, London (GB)
Filed on Jan. 14, 2022, as Appl. No. 17/576,218.
Application 17/576,218 is a continuation of application No. 17/066,713, filed on Oct. 9, 2020, granted, now 11,268,452.
Application 17/066,713 is a continuation of application No. 16/821,227, filed on Mar. 17, 2020, granted, now 10,851,715, issued on Dec. 1, 2020.
Claims priority of application No. 1917773 (GB), filed on Dec. 5, 2019.
Prior Publication US 2022/0307426 A1, Sep. 29, 2022
This patent is subject to a terminal disclaimer.
Int. Cl. F02K 3/06 (2006.01); F02C 7/36 (2006.01)
CPC F02C 7/36 (2013.01) [F02K 3/06 (2013.01); F05D 2200/14 (2013.01); F05D 2220/323 (2013.01); F05D 2220/36 (2013.01); F05D 2260/40311 (2013.01)] 18 Claims
OG exemplary drawing
 
1. A gas turbine engine for an aircraft comprising:
an engine core comprising a turbine, a compressor, and a core shaft connecting the turbine to the compressor;
a fan located upstream of the engine core, the fan comprising a plurality of fan blades, the fan having a fan axial centreline;
a gearbox that is configured to:
receive an input from the core shaft, and
output drive to a fan shaft via an output of the gearbox so as to drive the fan at a lower rotational speed than the core shaft; and
a fan shaft mounting structure arranged to mount the fan shaft within the engine, the fan shaft mounting structure comprising at least two supporting bearings connected to the fan shaft, wherein:
the fan comprises 22, 24 or 26 fan blades;
a system radial bending stiffness is defined as:

OG Complex Work Unit Math
a system tilt stiffness is defined as:

OG Complex Work Unit Math
and
either: (i) the system radial bending stiffness is greater than or equal to 3.90×106 N/m; or (ii) the system tilt stiffness is greater than or equal to 1.10×105 Nm/rad.