# US 10,370,974 B2 · Gas turbine engine airfoil > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,370,974 B2 - Document ID: US10370974B2 - Status: Granted - Kind: B2 - Application number: 14/836,577 - Filed: 2015-08-26 - Published: 2016-02-04 - Granted: 2019-08-06 - Earliest claimed: 2014-02-19 - Assignees: United Technologies Corporation - Applicants: United Technologies Corporation - Inventors: Edward J. Gallagher; Byron R. Monzon; Ling Liu; Linda S. Li; Darryl Whitlow; Barry M. Ford - Web page: https://patentgrep.com/patent/US10370974B2 ## CPC - F01D 5/141: {Shape, i.e. outer, aerodynamic form (F01D5/148 - F01D5/20 take precedence; blade construction F01D5/147)} - F01D 5/02: Blade-carrying members, e.g. rotors (rotors of non-bladed type F01D1/34; stators F01D9/00 {; selecting particular materials F01D5/28}) - F02C 3/107: with two or more rotors connected by power transmission - F02K 3/00: Plants including a gas turbine driving a compressor or a ducted fan - F05D 2200/222: Cubic power - F05D 2220/32: in gas turbines - F05D 2220/323: for aircraft propulsion, e.g. jet engines - F05D 2220/36: specially adapted for the fan of turbofan engines - F05D 2240/30: Characteristics of rotor blades, i.e. of any element transforming dynamic fluid energy to or from rotational energy and being attached to a rotor - F05D 2240/301: Cross-sectional characteristics - F05D 2250/713: inflexed - F05D 2260/40311: of the epicyclical, planetary or differential type - 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) - F02C: GAS-TURBINE PLANTS; AIR INTAKES FOR JET-PROPULSION PLANTS; CONTROLLING FUEL SUPPLY IN AIR-BREATHING JET-PROPULSION PLANTS (construction of turbines F01D; jet-propulsion plants F02K; construction of compressors or fans F04; generating combustion products of high pressure or high velocity F23R; using gas turbines in compression refrigeration plants F25B11/00) - 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 An airfoil of a turbine engine includes pressure and suction sides that extend in a radial direction from a 0% span position at an inner flow path location to a 100% span position at an airfoil tip. The airfoil has a relationship between a tangential stacking offset and a span position that is at least a third order polynomial curve that includes at least one positive and negative slope. The positive slope leans toward the suction side and the negative slope leans toward the pressure side. An initial slope starts at the 0% span position is either zero or positive. The first critical point is less than 15% span. ## Claims ### Claim 1 An airfoil of a turbine engine comprising: pressure and suction sides extending in a radial direction from a 0% span position at an inner flow path location to a 100% span position at an airfoil tip, wherein the airfoil has a relationship between a tangential stacking offset and a span position that is at least a third order polynomial curve that includes at least one positive and negative slope, the positive slope leans toward the suction side and the negative slope leans toward the pressure side, wherein an initial slope starting at the 0% span position is either zero or positive, wherein the first critical point is less than 15% span. ### Claim 2 (depends on 1) The airfoil according to claim 1, wherein the curve has at least two critical points. ### Claim 3 (depends on 2) The airfoil according to claim 2, wherein the airfoil extends from a root, and a zero tangential stacking offset corresponds to tangential center of the root. ### Claim 4 (depends on 2) The airfoil according to claim 2, wherein the curve has an initial positive slope. ### Claim 5 (depends on 4) The airfoil according to claim 4, wherein the first critical point has an Rd/Yd ratio in a range of 195 to 205. ### Claim 6 (depends on 4) The airfoil according to claim 4, wherein the second critical point is in the range of 35-45% span. ### Claim 7 (depends on 6) The airfoil according to claim 6, wherein the second critical point has an Rd/Yd ratio in a range of 1950 to 2050. ### Claim 8 (depends on 4) The airfoil according to claim 4, wherein the curve does not cross the zero tangential stacking offset. ### Claim 9 (depends on 4) The airfoil according to claim 4, wherein the curve crosses the zero tangential stacking offset once. ### Claim 10 (depends on 9) The airfoil according to claim 9, wherein a critical point in a 35-45% span range has a Rd/Yd ratio in a range of −70 to −74. ### Claim 11 (depends on 2) The airfoil according to claim 2, wherein the curve has an initial zero slope. ### Claim 12 (depends on 11) The airfoil according to claim 11, wherein the first critical point is in the range of 35-45% span. ### Claim 13 (depends on 12) The airfoil according to claim 12, wherein the first critical point has an Rd/Yd ratio in a range of −108 to −116. ### Claim 14 (depends on 11) The airfoil according to claim 11, wherein the second critical point is in the range of 85-95% span. ### Claim 15 (depends on 14) The airfoil according to claim 14, wherein the second critical point has an Rd/Yd ratio in a range of 23 to 26. ### Claim 16 (depends on 11) The airfoil according to claim 11, wherein the curve crosses the zero tangential stacking offset twice. ### Claim 17 (depends on 1) The airfoil according to claim 1, wherein the airfoil is a fan blade for a gas turbine engine. ### Claim 18 (depends on 17) The airfoil according to claim 17, wherein the fan blade is a composite blade. ### Claim 19 (depends on 18) The airfoil according to claim 18, wherein the composite blade is a swept blade. ### Claim 20 A gas turbine engine comprising: a combustor section arranged between a compressor section and a turbine section; a fan section having an array of twenty-six or fewer fan blades, wherein the fan section has a low fan pressure ratio of less than or equal to about 1.7; a geared architecture coupling the fan section to the turbine section or the compressor section; and wherein the fan blades include a root, and an airfoil having pressure and suction sides extending from the root in a radial direction from a 0% span position at an inner flow path location to a 100% span position at an airfoil tip, wherein the airfoil has a relationship between a tangential stacking offset and a span position that is at least a third order polynomial curve that includes at least one positive and negative slope, the positive slope leans toward the suction side and the negative slope leans toward the pressure side, wherein a zero tangential stacking offset corresponds to tangential center of the root, and the 0% span position is offset from the zero tangential stacking offset, wherein the first critical point is less than 15% span.