# US 10,865,649 B2 · Gas turbine engine > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,865,649 B2 - Document ID: US10865649B2 - Status: Granted - Kind: B2 - Application number: 15/467,328 - Filed: 2017-03-23 - Published: 2017-10-26 - Granted: 2020-12-15 - Earliest claimed: 2016-04-20 - Assignees: ROLLS-ROYCE plc - Applicants: ROLLS-ROYCE plc - Inventors: Matthew Thomas - Web page: https://patentgrep.com/patent/US10865649B2 ## CPC - F01D 5/282: {Selecting composite materials, e.g. blades with reinforcing filaments} - F01D 5/34: Rotor-blade aggregates of unitary construction {, e.g. formed of sheet laminae; (discs formed of sheet laminae F01D5/028; ceramic materials F01D5/284, composite materials F01D5/282)} - F04D 29/324: {Blades} - F04D 29/325: {for axial flow fans (blade mountings F04D29/34, blades F04D29/38)} - F04D 29/388: {characterised by construction} - F02K 3/06: with front fan - F05D 2220/32: in gas turbines - F05D 2220/36: specially adapted for the fan of turbofan engines - F05D 2230/31: Layer deposition - F05D 2300/603: Composites; e.g. fibre-reinforced - F05D 2300/6034: Orientation of fibres, weaving, ply angle - F05D 2300/614: Fibres or filaments - Y02T 50/60: Efficient propulsion technologies, e.g. for aircraft - F01D: NON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES (machines or engines for liquids F03; non-positive displacement pumps F04D) - F04D: NON-POSITIVE-DISPLACEMENT PUMPS (engine fuel-injection pumps F02M; ion pumps H01J41/12; electrodynamic pumps H02K44/02) - F02K: JET-PROPULSION PLANTS (features of jet-propulsion plants common to gas-turbine plants, air intakes or fuel supply control of air-breathing jet-propulsion plants F02C7/00, F02C9/00) - F05D: INDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS - Y02T: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION ## Abstract A gas turbine engine that includes a fan blade having a tip, a root, a pressure side, a suction side, a trailing edge and a leading edge, the fan blade including a laminate body defined by a plurality of plies comprising reinforcement fibres, wherein an angle of the fibres in the plies from the trailing edge to the leading edge at the suction side and/or the pressure side of the blade are arranged such that the laminate body is unbalanced so that, during rotation of the fan blade, the fan blade deforms such that a centre of mass of the blade rotates about a centre of rotation of the fan so as to move the centre of mass towards a balanced position. ## Claims ### Claim 1 A gas turbine engine comprising a fan blade having a tip, a root, a pressure side, a suction side, a trailing edge and a leading edge, the fan blade comprising: a laminate body defined by a plurality of plies comprising reinforcement fibres, wherein: an angle of the fibres in the plies from the trailing edge to the leading edge at the suction side and the pressure side of the fan blade are arranged such that the laminate body is unbalanced from the trailing edge to the leading edge so that, during rotation of the fan blade, the fan blade deforms such that a centre of mass of the fan blade rotates about a centre of rotation of the fan blade so as to move the centre of mass towards a balanced position, the fan blade comprises an inner region defined by a plurality of plies between the plies at the suction side and at the pressure side, and when at a state of rest, the angle of the fibres of the plies at the pressure side and the suction side continuously varies from the root to the tip of the fan blade and the plurality of plies of the inner region are arranged to be balanced and symmetric and a direction of the fibres of the plies of the inner region is substantially 0 degrees relative to a radial axis of the fan blade from the root to the tip of the fan blade. ### Claim 2 (depends on 1) The gas turbine engine according to claim 1, wherein the fibres in the plies at the pressure side and/or the suction side are arranged so as to define a non-symmetric laminate. ### Claim 3 (depends on 2) The gas turbine engine according to claim 2, wherein the fibres in the plies at the pressure side and/or the suction side are arranged to be anti-symmetric. ### Claim 4 (depends on 1) The gas turbine engine according to claim 1, wherein the plies at the pressure side and/or the suction side are arranged such that the fan blade is symmetric in a region proximal to the root and non-symmetric in a region proximal to the tip. ### Claim 5 (depends on 1) The gas turbine engine according to claim 1, wherein a fibre direction of the plies on the pressure side and/or the suction side of the fan blade have a positive or a negative angle in a region near the root of the fan blade. ### Claim 6 (depends on 1) The gas turbine engine according to claim 1, wherein a fibre direction of the plies at the suction side has a negative angle and/or a fibre direction of the plies on the pressure side of the fan blade has a positive angle proximal to the tip of the fan blade. ### Claim 7 (depends on 1) The gas turbine engine according to claim 1, wherein the inner region has a thickness between 30% and 70% of an overall blade thickness. ### Claim 8 (depends on 1) A method of manufacturing a fan blade of the gas turbine engine according to claim 1, the method comprising laying up a plurality of plies so as to define a laminate, and varying the fibre direction within the laminate such that the laminate is unbalanced. ### Claim 9 (depends on 8) The method according to claim 8, comprising defining the plies and the fibre direction of the plies using a pre-preg tape. ### Claim 10 (depends on 9) The method according to claim 9, wherein the plies are laid up using automated fibre placement. ### Claim 11 A gas turbine engine comprising a fan blade comprising a tip, a root, a pressure side, a suction side, a trailing edge and a leading edge, the fan blade comprising: a laminate body defined by a plurality of plies comprising reinforcement fibres, wherein: an angle of the fibres in the plies from the trailing edge to the leading edge at the pressure side and the suction side are arranged such that the laminate body is non-symmetric from the trailing edge to the leading edge, the fan blade comprises an inner region defined by a plurality of plies between the plies at the suction side and at the pressure side, and when at a state of rest, a direction of the reinforcement fibres in the plies at the pressure side and the suction side continuously varies from the root to the tip of the fan blade and the plurality of plies of the inner region are arranged to be balanced and symmetric and a direction of the fibres of the plies of the inner region is substantially 0 degrees relative to a radial axis of the fan blade from the root to the tip of the fan blade. ### Claim 12 A method of manufacturing a composite fan blade for a gas turbine engine, the composite fan blade including a laminate having a plurality of stacked plies, and the fan blade including a tip, a root, a pressure side, a suction side, a trailing edge and a leading edge, the method comprising: designing the plies of the laminate such that the laminate is unbalanced from the trailing edge to the leading edge so as to promote deformation of the fan blade when used under take off conditions compared to when used under cruise conditions, wherein, when at a state of rest, an angle of fibres of the plies at the pressure side and the suction side continuously varies from the root to the tip of the fan blade and a plurality of plies of an inner region between the plies at the suction side and at the pressure side are arranged to be balanced and symmetric and a direction of the fibres of the plies of the inner region is substantially 0 degrees relative to a radial axis of the fan blade from the root to the tip of the fan blade. ### Claim 13 (depends on 12) The method according to claim 12, comprising designing the plies of the laminate such that the laminate is non-symmetric, and selecting the angle of the fibres of the plies and the extent of non-symmetry to achieve a first configuration of fan blade under take off conditions and a second configuration of the fan blade under cruise conditions. ### Claim 14 (depends on 13) The method according to claim 13, wherein the angle of the fibres and the extent of non-symmetry of the plies is selected so as to utilise change in temperature between take off and cruise, and/or the difference in forces acting on the fan blade.