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US20130136616A1 - Propeller blade having a honeycomb spar core - Google Patents

Propeller blade having a honeycomb spar core Download PDF

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Publication number
US20130136616A1
US20130136616A1 US13/690,212 US201213690212A US2013136616A1 US 20130136616 A1 US20130136616 A1 US 20130136616A1 US 201213690212 A US201213690212 A US 201213690212A US 2013136616 A1 US2013136616 A1 US 2013136616A1
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US
United States
Prior art keywords
spar
core
propeller blade
structural layer
honeycomb core
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Abandoned
Application number
US13/690,212
Inventor
Ludovic Prunet
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Ratier Figeac SAS
Original Assignee
Ratier Figeac SAS
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Ratier Figeac SAS filed Critical Ratier Figeac SAS
Assigned to RATIER-FIGEAC SAS reassignment RATIER-FIGEAC SAS ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: Prunet, Ludovic
Publication of US20130136616A1 publication Critical patent/US20130136616A1/en
Abandoned legal-status Critical Current

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01D—NON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES
    • F01D5/00—Blades; Blade-carrying members; Heating, heat-insulating, cooling or antivibration means on the blades or the members
    • F01D5/12—Blades
    • F01D5/14—Form or construction
    • F01D5/141—Shape, i.e. outer, aerodynamic form
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B64—AIRCRAFT; AVIATION; COSMONAUTICS
    • B64C—AEROPLANES; HELICOPTERS
    • B64C11/00—Propellers, e.g. of ducted type; Features common to propellers and rotors for rotorcraft
    • B64C11/16—Blades
    • B64C11/20—Constructional features
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B64—AIRCRAFT; AVIATION; COSMONAUTICS
    • B64C—AEROPLANES; HELICOPTERS
    • B64C11/00—Propellers, e.g. of ducted type; Features common to propellers and rotors for rotorcraft
    • B64C11/16—Blades
    • B64C11/20—Constructional features
    • B64C11/22—Solid blades
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B64—AIRCRAFT; AVIATION; COSMONAUTICS
    • B64D—EQUIPMENT FOR FITTING IN OR TO AIRCRAFT; FLIGHT SUITS; PARACHUTES; ARRANGEMENT OR MOUNTING OF POWER PLANTS OR PROPULSION TRANSMISSIONS IN AIRCRAFT
    • B64D27/00—Arrangement or mounting of power plants in aircraft; Aircraft characterised by the type or position of power plants
    • B64D2027/005—Aircraft with an unducted turbofan comprising contra-rotating rotors, e.g. contra-rotating open rotors [CROR]
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B64—AIRCRAFT; AVIATION; COSMONAUTICS
    • B64D—EQUIPMENT FOR FITTING IN OR TO AIRCRAFT; FLIGHT SUITS; PARACHUTES; ARRANGEMENT OR MOUNTING OF POWER PLANTS OR PROPULSION TRANSMISSIONS IN AIRCRAFT
    • B64D27/00—Arrangement or mounting of power plants in aircraft; Aircraft characterised by the type or position of power plants
    • B64D27/02—Aircraft characterised by the type or position of power plants
    • B64D27/026—Aircraft characterised by the type or position of power plants comprising different types of power plants, e.g. combination of a piston engine and a gas-turbine
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T50/00—Aeronautics or air transport
    • Y02T50/60—Efficient propulsion technologies, e.g. for aircraft
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T29/00—Metal working
    • Y10T29/49—Method of mechanical manufacture
    • Y10T29/49316—Impeller making
    • Y10T29/49332—Propeller making

Definitions

  • the present invention relates to propellers and, in particular, to propeller blades formed having a honeycomb spar core.
  • Modern propeller blades typically include root portions which extend into the hub arm of the hub of the propeller system and which are secured to and rotatable relative to the hub arm via a retention assembly.
  • the retention assembly includes one or a plurality of ball bearing assemblies which permit the rotation of the blade in the hub arm for accomplishing pitch change of the blade for altering the speed of the propeller and accordingly, the aircraft.
  • the blades are typically formed by surrounding a foam spar core with a resin impregnated fabric. Leading and trailing edges of the blade are then formed over the fabric and surrounded by, for example, a Kevlar sock. Such blades are light and effective for their intended purposes.
  • a propeller blade that includes a honeycomb core and a structural layer that surrounds at least a portion of the honeycomb core is disclosed.
  • a method of forming a propeller blade that includes forming a honeycomb core and disposing a structural layer over at least a portion of the honeycomb core is disclosed.
  • FIG. 1 is a plan-view of a prior art propeller blade
  • FIG. 2 is a cross-section of the propeller blade shown in FIG. 1 ;
  • FIG. 3 is cross-section of a propeller blade according to one embodiment of the present invention.
  • FIG. 1 a plan view of a conventional propeller blade 100 is illustrated and will be used to define certain terms, explain how a propeller blade is generally made, and to illustrate the differences between embodiments of the present invention and the prior art.
  • FIG. 2 is a cross-section of the propeller blade 100 of FIG. 1 taken along line A-A, for these purposes.
  • the blade 100 is formed by first forming a spar 102 .
  • the spar 102 includes a spar foam core 104 surrounded by a structural layer 106 .
  • the core 104 is typically formed of a foam material that is injected into a mold.
  • the mold can include a layer of fiberglass on the walls thereof to which the foam of the core 104 adheres.
  • the core 104 can be surrounded by a layer of fiberglass (not shown) but this can be omitted.
  • the structural layer 106 is typically formed of a fabric material (e.g. resin impregnated braided carbon fiber material) and disposed such that it surrounds the core 104 (and the fiberglass layer if it is included). In some cases, the spar 102 is heated to set the resin in the structural layer 106 . It has been discovered that, in some instances, considerable thermal stresses can occur in the core 104 as the spar 102 is cooled due to the differences in the coefficients of thermal expansion (CTE) of the core 104 and the structural layer 106 .
  • CTE coefficients of thermal expansion
  • the spar 102 is formed such that a portion of it is surrounded by a root portion 108 that allows the blade 100 to be connected to a hub (not shown). Rotation of the hub causes the blade 100 to rotate and, consequently, causes the generation of thrust to propel an aircraft. In the following discussion, it shall be assumed that the blade 100 rotates in the clockwise direction.
  • the root portion 108 is sometimes referred to as a “tulip” in the industry and is typically formed of a metal.
  • leading edge foam 110 and trailing edge foam 112 are formed on the leading and trailing edges 114 , 116 , respectively of the spar 102 .
  • the leading edge foam 110 , trailing edge foam 112 and the spar 102 can then be encased in an outer layer 118 .
  • the outer layer 118 can be formed of Kevlar and be in the form of a sock that is pulled over the assembly that includes the leading edge foam 110 , trailing edge foam 112 and the spar 102 .
  • the outer layer 118 could be formed in other manners as well.
  • thermal stresses can occur in the core 104 as the spar 102 is cooled due to the differences in the coefficients of thermal expansion (CTE) of the core 104 and the structural layer 106 . These stresses can lead to the cracking of the core 104 and debonding of it from the structural layer 106 .
  • thermal stresses can be created between the core 104 and the structural layer 106 due to the wide range of temperatures experienced by the propeller blade 100 in normal operation.
  • FIG. 3 illustrates a cut-away side view of a propeller blade 200 according to one embodiment of the present invention.
  • the blade 200 is formed by first forming a spar 202 .
  • the spar 202 includes a spar core 204 .
  • the spar core is not formed of a foam material.
  • the spar core 204 is formed of a material arranged in a honeycomb configuration 205 .
  • the honeycomb configuration 205 arranges the material in a plurality of substantially geometrically shaped interconnected cells.
  • the honeycomb configuration 205 may extend structural support members in polygon shapes, for example hexagonal shapes, forming an array of cells in the spar core 204 .
  • the exact shape and orientation of each cell can vary and not every cell has to have cells of the same geometric shape.
  • the spar core 204 can be formed either in a mold or can be shaped from a larger piece of honeycomb material.
  • the spar core 204 can be formed of carbon, fiberglass or any other suitable composite or non-composite material.
  • a structural layer 206 can then be formed around the spar core 204 .
  • the structural layer 206 is formed of a resin-impregnated fiber material, such as a resin-impregnated braided carbon sheet, and disposed such that it surrounds spar core 204 (and the fiberglass layer if present).
  • the spar 202 is heated to set the resin in the structural layer 206 .
  • the resin can penetrate the spar core 204 and more tightly bond it to the structural layer 206 .
  • the material of the spar core 204 can be selected such that it more closely matches the CTE of the structural layer 206 to reduce stresses that can be experienced during cooling as describe above. Such a reduction in thermal stresses can prevent or reduce cracking of the core 204 and, thereby, reduce the possibility of the core 204 and the structural layer 206 becoming debonded from one another.
  • the spar 202 can be formed such that a portion of it is surrounded by a root portion that allows the blade 200 to be connected to a hub (not shown). Rotation of the hub causes the blade 200 to rotate and, consequently, causes the generation of thrust to propel an aircraft.
  • leading edge foam 210 and trailing edge foam 212 are formed on the leading and trailing edges 214 , 216 , respectively of the spar 202 .
  • the leading edge foam 210 , trailing edge foam 212 and the spar 202 can then be encased in an outer layer 218 .
  • the outer layer 218 can be formed of Kevlar and in the form of a sock that is pulled over the assembly that includes the leading edge foam 212 , trailing edge foam 214 and the spar 202 .
  • the outer layer 218 could be formed in other manners as well.
  • Replacing the spar foam core 104 with the spar core 204 having the honeycomb configuration 205 can prevent debonding which may otherwise occur between the spar foam core 104 and structural layer 106 . This may be achieved because the honeycomb material can be selected to be more thermally compatible with the structural layer 206 , and has a higher strength than foam.

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  • Engineering & Computer Science (AREA)
  • Aviation & Aerospace Engineering (AREA)
  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Laminated Bodies (AREA)

Abstract

A propeller blade includes a honeycomb core and a structural layer that surrounds at least a portion of the honeycomb core.

Description

    PRIORITY CLAIM
  • This application claims priority to European Patent Application No. 11306585.8, filed Nov. 30, 2011, and all the benefits accruing therefrom under 35 U.S.C. §119, the contents of which in its entirety are herein incorporated by reference.
    • BACKGROUND OF THE INVENTION
  • The present invention relates to propellers and, in particular, to propeller blades formed having a honeycomb spar core.
  • Modern propeller blades typically include root portions which extend into the hub arm of the hub of the propeller system and which are secured to and rotatable relative to the hub arm via a retention assembly. Typically the retention assembly includes one or a plurality of ball bearing assemblies which permit the rotation of the blade in the hub arm for accomplishing pitch change of the blade for altering the speed of the propeller and accordingly, the aircraft.
  • The blades are typically formed by surrounding a foam spar core with a resin impregnated fabric. Leading and trailing edges of the blade are then formed over the fabric and surrounded by, for example, a Kevlar sock. Such blades are light and effective for their intended purposes.
    • BRIEF DESCRIPTION OF THE INVENTION
  • According to one embodiment, a propeller blade that includes a honeycomb core and a structural layer that surrounds at least a portion of the honeycomb core is disclosed.
  • According to another embodiment, a method of forming a propeller blade that includes forming a honeycomb core and disposing a structural layer over at least a portion of the honeycomb core is disclosed.
    • BRIEF DESCRIPTION OF THE DRAWINGS
  • The subject matter which is regarded as the invention is particularly pointed out and distinctly claimed in the claims at the conclusion of the specification. The foregoing and other features, and advantages of the invention are apparent from the following detailed description taken in conjunction with the accompanying drawings in which:
  • FIG. 1 is a plan-view of a prior art propeller blade;
  • FIG. 2 is a cross-section of the propeller blade shown in FIG. 1; and
  • FIG. 3 is cross-section of a propeller blade according to one embodiment of the present invention.
    •  DETAILED DESCRIPTION OF THE INVENTION
  • Referring now to FIG. 1, a plan view of a conventional propeller blade 100 is illustrated and will be used to define certain terms, explain how a propeller blade is generally made, and to illustrate the differences between embodiments of the present invention and the prior art. Reference will also be made to FIG. 2, which is a cross-section of the propeller blade 100 of FIG. 1 taken along line A-A, for these purposes.
  • The blade 100 is formed by first forming a spar 102. The spar 102 includes a spar foam core 104 surrounded by a structural layer 106. The core 104 is typically formed of a foam material that is injected into a mold. The mold can include a layer of fiberglass on the walls thereof to which the foam of the core 104 adheres. As such, the core 104 can be surrounded by a layer of fiberglass (not shown) but this can be omitted.
  • The structural layer 106 is typically formed of a fabric material (e.g. resin impregnated braided carbon fiber material) and disposed such that it surrounds the core 104 (and the fiberglass layer if it is included). In some cases, the spar 102 is heated to set the resin in the structural layer 106. It has been discovered that, in some instances, considerable thermal stresses can occur in the core 104 as the spar 102 is cooled due to the differences in the coefficients of thermal expansion (CTE) of the core 104 and the structural layer 106.
  • In some instances, the spar 102 is formed such that a portion of it is surrounded by a root portion 108 that allows the blade 100 to be connected to a hub (not shown). Rotation of the hub causes the blade 100 to rotate and, consequently, causes the generation of thrust to propel an aircraft. In the following discussion, it shall be assumed that the blade 100 rotates in the clockwise direction. The root portion 108 is sometimes referred to as a “tulip” in the industry and is typically formed of a metal.
  • After the spar 102 is formed, leading edge foam 110 and trailing edge foam 112 are formed on the leading and trailing edges 114, 116, respectively of the spar 102. The leading edge foam 110, trailing edge foam 112 and the spar 102 can then be encased in an outer layer 118. The outer layer 118 can be formed of Kevlar and be in the form of a sock that is pulled over the assembly that includes the leading edge foam 110, trailing edge foam 112 and the spar 102. Of course, the outer layer 118 could be formed in other manners as well.
  • As described above, considerable thermal stresses can occur in the core 104 as the spar 102 is cooled due to the differences in the coefficients of thermal expansion (CTE) of the core 104 and the structural layer 106. These stresses can lead to the cracking of the core 104 and debonding of it from the structural layer 106. In addition, thermal stresses can be created between the core 104 and the structural layer 106 due to the wide range of temperatures experienced by the propeller blade 100 in normal operation.
  • FIG. 3 illustrates a cut-away side view of a propeller blade 200 according to one embodiment of the present invention. The blade 200 is formed by first forming a spar 202. The spar 202 includes a spar core 204. Unlike the prior art, the spar core is not formed of a foam material. Rather, according to one embodiment, the spar core 204 is formed of a material arranged in a honeycomb configuration 205. The honeycomb configuration 205 arranges the material in a plurality of substantially geometrically shaped interconnected cells. The honeycomb configuration 205 may extend structural support members in polygon shapes, for example hexagonal shapes, forming an array of cells in the spar core 204. Of course, the exact shape and orientation of each cell can vary and not every cell has to have cells of the same geometric shape.
  • The spar core 204 can be formed either in a mold or can be shaped from a larger piece of honeycomb material. The spar core 204 can be formed of carbon, fiberglass or any other suitable composite or non-composite material.
  • A structural layer 206 can then be formed around the spar core 204. In one embodiment, the structural layer 206 is formed of a resin-impregnated fiber material, such as a resin-impregnated braided carbon sheet, and disposed such that it surrounds spar core 204 (and the fiberglass layer if present). In some cases, the spar 202 is heated to set the resin in the structural layer 206. In contrast to the prior art, due to cells of the spar core, the resin can penetrate the spar core 204 and more tightly bond it to the structural layer 206. In addition, the material of the spar core 204 can be selected such that it more closely matches the CTE of the structural layer 206 to reduce stresses that can be experienced during cooling as describe above. Such a reduction in thermal stresses can prevent or reduce cracking of the core 204 and, thereby, reduce the possibility of the core 204 and the structural layer 206 becoming debonded from one another.
  • While not illustrated in FIG. 3, the spar 202 can be formed such that a portion of it is surrounded by a root portion that allows the blade 200 to be connected to a hub (not shown). Rotation of the hub causes the blade 200 to rotate and, consequently, causes the generation of thrust to propel an aircraft.
  • After the spar 202 is formed, leading edge foam 210 and trailing edge foam 212 are formed on the leading and trailing edges 214, 216, respectively of the spar 202. The leading edge foam 210, trailing edge foam 212 and the spar 202 can then be encased in an outer layer 218. The outer layer 218 can be formed of Kevlar and in the form of a sock that is pulled over the assembly that includes the leading edge foam 212, trailing edge foam 214 and the spar 202. Of course, the outer layer 218 could be formed in other manners as well.
  • Replacing the spar foam core 104 with the spar core 204 having the honeycomb configuration 205 (i.e., a honeycomb core), can prevent debonding which may otherwise occur between the spar foam core 104 and structural layer 106. This may be achieved because the honeycomb material can be selected to be more thermally compatible with the structural layer 206, and has a higher strength than foam.
  • While the invention has been described in detail in connection with only a limited number of embodiments, it should be readily understood that the invention is not limited to such disclosed embodiments. Rather, the invention can be modified to incorporate any number of variations, alterations, substitutions or equivalent arrangements not heretofore described, but which are commensurate with the spirit and scope of the invention. Additionally, while various embodiments of the invention have been described, it is to be understood that aspects of the invention may include only some of the described embodiments. Accordingly, the invention is not to be seen as limited by the foregoing description, but is only limited by the scope of the appended claims.

Claims (12)

1. A propeller blade comprising:
a honeycomb core; and
a structural layer that surrounds at least a portion of the honeycomb core.
2. The propeller blade of claim 1, further comprising:
a layer of fiberglass at least partially disposed between the honeycomb core and the structural layer.
3. The propeller blade of claim 1, further comprising:
a root disposed within the structural layer at an end of the propeller blade.
4. The propeller blade of claim 3, wherein the root surrounds a portion of the honeycomb core.
5. The propeller blade of claim 1, wherein the honeycomb core is formed of fiberglass, carbon, a composite material or any combination thereof.
6. The propeller blade of claim 1, wherein the structural layer is formed of a resin-impregnated fiber material.
7. The propeller blade of claim 1, wherein the structural layer is formed of a resin-impregnated braided carbon fiber sheet.
8. A method of forming a propeller blade comprising:
forming a honeycomb core; and
disposing a structural layer over at least a portion of the honeycomb core.
9. The method of claim 8, further comprising:
coupling a root to the honeycomb core;
wherein disposing includes disposing the structural layer over at least a portion of the root.
10. The method of claim 8, wherein the honeycomb core is formed of fiberglass, carbon, a composite material or any combination thereof.
11. The method of claim 8, wherein the structural layer is formed of a resin-impregnated fiber material.
12. The method of claim 8, wherein the structural layer is formed of a resin-impregnated braided carbon fiber sheet.
US13/690,212 2011-11-30 2012-11-30 Propeller blade having a honeycomb spar core Abandoned US20130136616A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
EP11306585.8A EP2599713A1 (en) 2011-11-30 2011-11-30 Propeller blade having a honeycomb spar core
EP11306585.8 2011-11-30

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Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20130343898A1 (en) * 2012-06-26 2013-12-26 Hamilton Sundstrand Corporation Propeller blade with carbon foam spar core
US11795827B1 (en) 2022-04-04 2023-10-24 General Electric Company Airfoil assembly with a structurally reinforced foam core
US12241386B2 (en) 2023-02-21 2025-03-04 General Electric Company Turbine engine airfoil with a woven core and woven layer

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR101617099B1 (en) 2014-11-05 2016-04-29 롯데케미칼 주식회사 Thermoplastic resin composition for 3d printer filaments
CN104608923B (en) * 2015-01-31 2016-05-11 中南大学 A kind of honeycomb fashion six rotor transporter aircrafts

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3754840A (en) * 1972-05-31 1973-08-28 United Aircraft Corp Composite helicopter rotor and blade
US5222297A (en) * 1991-10-18 1993-06-29 United Technologies Corporation Composite blade manufacture
FR2942278B1 (en) * 2009-02-17 2015-06-19 Airbus France DAWN FOR AIRCRAFT TURBOMACHINE RECEIVER, PROVIDED WITH TWO HOLLOW ACTS ALLOWED IN ONE ANOTHER
FR2954271B1 (en) * 2009-12-21 2012-02-17 Snecma AIRCRAFT PROPELLER BLADE

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20130343898A1 (en) * 2012-06-26 2013-12-26 Hamilton Sundstrand Corporation Propeller blade with carbon foam spar core
US9139287B2 (en) * 2012-06-26 2015-09-22 Hamilton Sundstrand Corporation Propeller blade with carbon foam spar core
US11795827B1 (en) 2022-04-04 2023-10-24 General Electric Company Airfoil assembly with a structurally reinforced foam core
US12241386B2 (en) 2023-02-21 2025-03-04 General Electric Company Turbine engine airfoil with a woven core and woven layer

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AS Assignment

Owner name: RATIER-FIGEAC SAS, FRANCE

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:PRUNET, LUDOVIC;REEL/FRAME:029381/0518

Effective date: 20111103

STCB Information on status: application discontinuation

Free format text: ABANDONED -- FAILURE TO RESPOND TO AN OFFICE ACTION

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