US3824037A - Suspension of rotor blades on the rotor head of a rotorcraft without the use of flapping or drag hinges - Google Patents

Suspension of rotor blades on the rotor head of a rotorcraft without the use of flapping or drag hinges Download PDF

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Publication number
US3824037A
US3824037A US00295730A US29573072A US3824037A US 3824037 A US3824037 A US 3824037A US 00295730 A US00295730 A US 00295730A US 29573072 A US29573072 A US 29573072A US 3824037 A US3824037 A US 3824037A
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US
United States
Prior art keywords
rotor
elastic band
rotor blades
breakage
blades
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.)
Expired - Lifetime
Application number
US00295730A
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English (en)
Inventor
A Schwarz
K Mautz
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.)
Airbus Defence and Space GmbH
Original Assignee
Messerschmitt Bolkow Blohm AG
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 Messerschmitt Bolkow Blohm AG filed Critical Messerschmitt Bolkow Blohm AG
Application granted granted Critical
Publication of US3824037A publication Critical patent/US3824037A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B64—AIRCRAFT; AVIATION; COSMONAUTICS
    • B64C—AEROPLANES; HELICOPTERS
    • B64C27/00—Rotorcraft; Rotors peculiar thereto
    • B64C27/32—Rotors
    • B64C27/37—Rotors having articulated joints
    • B64C27/45—Rotors having articulated joints with a feathering hinge only
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B64—AIRCRAFT; AVIATION; COSMONAUTICS
    • B64C—AEROPLANES; HELICOPTERS
    • B64C27/00—Rotorcraft; Rotors peculiar thereto
    • B64C27/32—Rotors
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B64—AIRCRAFT; AVIATION; COSMONAUTICS
    • B64C—AEROPLANES; HELICOPTERS
    • B64C27/00—Rotorcraft; Rotors peculiar thereto
    • B64C27/32—Rotors
    • B64C27/327—Retention means relieving the stress from the arm, e.g. tie-bars

Definitions

  • bands of stiffly resilient material encircling the central member and further similar bands are arranged around the holding sleeve.
  • the rotor blade will not only be temporarily held in operational position but will be permitted to move radially outwardly sufficiently to slightly unbalance the rotor and thereby give the pilot warning of the occurrence of damage.
  • the resilient bands will in the event of breakage hold the parts in operating relationship for a sufficient period of time to maintain the rotor operational until the break is presumably discovered on a routine inspection.
  • the purpose of the invention is to provide simple means by which the central member and the blade-base sleeves can be made operatively redundant in case of a breakdown resulting from a break in the zone of the fastening means thereof.
  • torsion-elastic, unitary, combined tension lamellae which are arranged parallel to the rotating plane of the rotor and are secured on a central member which is arranged coaxially to the rotor axis on the rotor head, it is provided by the invention that the central member be enclosed on its periphery at least by one bandage winding", as a band.
  • each one blade-base sleeve which is associated with each rotor blade and is fixedly connected to same by at least one pin is rotatably connected to each one blade-anglebearing sleeve which is provided on the rotor head, it is additionally provided that the pin be supported in openings in the blade-base sleeves which are each peripherally enclosed by at least one bandage winding, as a band.
  • the centrifugal forces which originate in the rotor blades are received by the bands and if necessary are transmitted thereby.
  • the bands consist of a fiber-reinforced, particularly glassfiber-reinforced plastic.
  • an unbalance is created by a radially outward movement of the fastening means for the ten- LII sion lamellae or the pin for the blade-base sleeves at the rotor hub.
  • Such unbalance cannot be withstood for any extended period of operation and thus is an indication to the pilot that a break has occurred in the central member and/or one, or possibly more, of the bladebase sleeves. The pilot will then land immediately.
  • the bands may also consist of steel wire or boron fibers.
  • the unbalance at the rotor hub may be so small that it is not noticed by the pilot. Therefore one can so design such bands that they can be loaded over a longer period of time and damage thereto is perhaps recognized only during an inspection'of the aircraft.
  • FIG. 1 is a side view of the central portion of a rotor, wherein one rotor arm is illustrated in a cross-sectional view and another in a longitudinal sectional view;
  • FIG. 2 illustrates a detail of FIG. 1 on an enlarged scale
  • FIG. 3 is a sectional view along the line III-III of FIG. 2 and FIG. 4 is an also enlarged sectional view along the line IVIV of FIG. 1.
  • a rotor head 1 of a four-blade rotor is fixedly connected to a rotor shaft 3 by screws 2.
  • the rotor head 1 consists substantially of four radially outwardly extending rotor arms which comprise housings 4 for the blade-angle-bearings.
  • a blade-base sleeve 7 is rotatably supported in each of the blade-angle-bearing housings 4 through roller bearings 5 and 6, said bladebase sleeve 7 serving at the same time as a mounting for the associated rotor blade 8.
  • the pivotal and bending moments which act on the rotor blades 8 are conducted to the rotor head 1 through the blade-base sleeves and the roller bearings 5 and 6.
  • sleeve holding devices 9 arranged in the blade-base sleeves.
  • Said sleeve holding devices are each supported on their sides toward'the rotor axis against a shoulder 10 and are each connected to a pin 12 through package-like, combined, continuous tension or nonextensible, torsionally and elastically deformable lamellae 11 in the form of a continuous lamellae strip.
  • Said pin 12 is supported in the rotor housing 1 coaxially with the rotor axis.
  • the connection between the tension lamellae 11 and the associated sleeve holding devices 9 is provided by a connecting pin 13 which is guided through an opening 14 in the tension lamellae and is supported in the sleeve holding device.
  • both of the cen- I tral members 15 are provided each with one band 20 endless turns or bands (FIG. 3) and are each embedded in a groove 21 on the periphery of the associated central member part (FIG. 2 illustrates the lower one of the two central member parts). They are made of any appropriate material, such as a glass-fiber-reinforced plastic.
  • bands 20 will stretch upon a breakage of the central member in the zone of one or more of its openings. 17 under the effect of the centrifugal forces caused by the respective rotor blades 8. A slight radially outward movement of the connecting pin 16 then takes place at the breakage point in question and results in an unbalance at the rotorhub. This gives the pilot an immediate indication of damage.
  • each central member part is provided on its periphery near each opening 17 with two concave recesses 22 which extend approximately parallel to the rotor axis (FIG. 3).
  • FIG. 3 the opening zone as a practical matter only such breaks will occur as are illustrated by lines 23 extending from the respective opening 17 to the nearest recess 22. Since the bands 20 will not touch these break points, damage to the bands by the broken edges is impossible.
  • bands 20 of fiber-reinforced plastic bands made of steel wire or boron fibers can also be used which can be secured against mechanical damage or splitting by a further band or an elastomer on a silicone or polyurethane base.
  • the use of such bands has the advantage that the individual strands of the bands which secure the central member (which bands are steel wire or boron fiber bands) can move with respect to one another when under load.
  • the safety of the central member 15 against breakdown is enhanced in a simple manner by the bands 20.
  • the blade-base sleeves 7 with which each associated rotor blade 8 is connected through a pin 24 As is illustrated in FIG. 1, said bolt 24 is supported in the associated blade-base sleeve 7 in openings 25 provided therein and further supported by bands 26 of glass-fiber-reinforced plastic.
  • the bands 26 are secured in placeby suitable collars on sleeves 27.
  • Each of openings 25 is further provided with two concave recesses 28 (FIG. 4).
  • a coating which resists mechanical abrasion may be made of lacquer or a plastic, as polytetrafluoroethylene or the like.
  • same can also be constructed as a single piece. Further a rectangular form of the central member is not essential for, for example, by utilizing an uneven number of lamellae bands it can also be constructed triangularly or in other polygonal shapes.
  • a suspension device for a plurality of rotor blades on rotor head means of a rotorcraft which is devoid or flapping and drag hinges in the connection between said rotor blades and said rotor head means
  • said suspension device having a rotatable rotor shaft supporting said rotor head means for rotation therewith, said plurality of elongated blades being mounted on said rotor head means and extending radially outwardly therefrom, support means for supporting eachof said plurality of elongated rotor blades for rotational movement about an axis parallel to the longitudinal axis of said rotor blades and a plurality of nonextensible, torsionally and elastically deformable members for secur ing said rotor head means to each of said rotor blades, the improvement comprising:
  • At least one central dislike member mounted on said rotor head means coaxial with the axis of rotation thereof and being rotatable therewith, said central member including means for permitting a connection to each of said nonextensible, torsionally and elastically deformable members; and elastic band means encircling said central dislike member to retain said central dislike member in an operating condition if said central dislike member should break during usage thereof, said broken central dislike member, and said elastic band means, during a rotation thereof, imparting one of a purposeful imbalance to said suspension device to thereby warn a pilot of the occurrence of a broken component in said suspension device and an insignificant amount of imbalance so that said breakage will be detected during inspection of said rotorcraft.
  • said support means for each of said elongated rotor blades includes means defining an opening therein spaced radially outwardly from said rotor head means, said rotor blade having a pin thereon adapted to be received in said opening and further elastic band means encircling said means defining said opening to retain said means in an operating condition if said means should break during usage thereof, said means, when broken, and said further elastic band means imparting one of a purposeful imbalance to said suspension device to thereby warn a pilot of the occurrence of a broken component in said suspension device and an insignificant amount of imbalance so that said breakage will bedetected during inspection of said rotorcraft.
  • said means defining said opening has a plurality of recesses in the periphery thereof to encourage breakage to occur at the location of said recesses to isolate the breakage from said further elastic band means.
  • each of said elastic bands is secured by a further band of an elastomer on a silicone or polyurethane base.
  • central disklike member has a plurality of recesses in the periphery thereof to encourage breakage to occur at the location of said recesses to isolate the breakage from said elastic band means.
  • said further elastic band means consists of a fiberreinforced plastic.
  • said further elastic band means consist of steel wire or boron fibers.
  • suspension device for a plurality of rotor blades on rotor head means of a rotorcraft which is devoid of flapping and drag hinges in the connection between said rotor blades and said rotor head means, said suspension device having a rotatable rotor shaft supporting said rotor head means for rotation therewith, said plurality of elongated blades being mounted on said rotor head means and extending radially outwardly therefrom, support means for supporting each of said plurality of elongated rotor blades for rotational movement about an axis parallel to the longitudinal axis of said rotor blades and a plurality of nonextensible, torsionally and elastically deformable members for securing said rotor head means to each of said rotor blades,

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Aviation & Aerospace Engineering (AREA)
  • Centrifugal Separators (AREA)
  • Moulding By Coating Moulds (AREA)
  • Structures Of Non-Positive Displacement Pumps (AREA)
  • Harvester Elements (AREA)
US00295730A 1971-10-12 1972-10-06 Suspension of rotor blades on the rotor head of a rotorcraft without the use of flapping or drag hinges Expired - Lifetime US3824037A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DE2150741A DE2150741C3 (de) 1971-10-12 1971-10-12 Schlag- und schwenkgelenklose Aufhaengung der Rotorblaetter eines Drehfluegelflugzeuges am Rotorkopf

Publications (1)

Publication Number Publication Date
US3824037A true US3824037A (en) 1974-07-16

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ID=5822102

Family Applications (1)

Application Number Title Priority Date Filing Date
US00295730A Expired - Lifetime US3824037A (en) 1971-10-12 1972-10-06 Suspension of rotor blades on the rotor head of a rotorcraft without the use of flapping or drag hinges

Country Status (5)

Country Link
US (1) US3824037A (enrdf_load_stackoverflow)
DE (1) DE2150741C3 (enrdf_load_stackoverflow)
FR (1) FR2156182B1 (enrdf_load_stackoverflow)
GB (1) GB1399704A (enrdf_load_stackoverflow)
IT (1) IT968834B (enrdf_load_stackoverflow)

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4183718A (en) * 1976-12-11 1980-01-15 Messerschmitt-Bolkow-Blohm Gmbh Rotor for a rotary wing aircraft
US4195967A (en) * 1976-10-26 1980-04-01 Messerschmitt-Boelkow-Blohm Gmbh Rotor free of flapping hinges and free of lead-lag hinges
US4264277A (en) * 1978-05-26 1981-04-28 The Boeing Company Redundant rotor blade retention system
US4516909A (en) * 1982-03-11 1985-05-14 Costruzioni Aeronautiche Giovanni Agusta S.P.A. Helicopter Rotor
US4521157A (en) * 1982-03-11 1985-06-04 Costruzioni Aeronautiche Giovanni Agusta S.P.A. Helicopter rotor hub
US4626173A (en) * 1983-03-18 1986-12-02 Societe Nationale Industrielle Et Aerospatiale Variable-pitch multi-blade propeller incorporating individually dismountable blades made of composite materials, process for manufacturing such blades and blades thus produced
US5340279A (en) * 1992-06-22 1994-08-23 United Technologies Corporation Snubber assembly for a rotor assembly having ducted, coaxial counter-rotating rotors
US20050079053A1 (en) * 2003-10-08 2005-04-14 Perkinson Robert H. Cyclic actuation system for a controllable pitch propeller and a method of providing aircraft control therewith
US20180002002A1 (en) * 2016-02-22 2018-01-04 Sikorsky Aircraft Corporation Rotor assembly including a one piece molding rotor hub

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3942910A (en) * 1974-05-13 1976-03-09 Textron, Inc. Grip-yoke assembly with a redundant centrifugal load support
FR2442991A1 (fr) * 1978-11-30 1980-06-27 Vibrachoc Sa Isolateur de vibrations
IT1143358B (it) * 1981-02-05 1986-10-22 Agusta Aeronaut Costr Mozzo composito di un rotore di elicottero
US4545733A (en) * 1982-03-18 1985-10-08 Messerschmitt-Boelkow-Blohm Gesellschaft Mit Beschraenkter Haftung Apparatus for adjusting the tracking of the blades in a rotor, especially for a rotary wing aircraft
FR2529860B1 (fr) * 1982-07-08 1987-01-02 Aerospatiale Plateau de moyeu, procede de fabrication et moyeu de rotor de giravion equipe de tels plateaux

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1190259A (en) * 1967-07-01 1970-04-29 Bolkow Gmbh Improvements in Rotor Assemblies for a Rotor Craft
US3545880A (en) * 1967-07-31 1970-12-08 Sud Aviat Soc Nationale De Con Rotor for rotary-wing aircraft
US3591310A (en) * 1968-07-04 1971-07-06 Sud Aviat Soc Nationale De Con Articulated hub for helicopter rotor
US3610774A (en) * 1968-10-30 1971-10-05 Sud Aviat Soc Nationale De Con Rotors for rotary-wing aircraft
US3625634A (en) * 1969-12-10 1971-12-07 Gen Motors Corp Turbomachine rotor
US3679322A (en) * 1969-05-28 1972-07-25 Aerospatiale Rotor hubs on rotary wing aircraft

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1190259A (en) * 1967-07-01 1970-04-29 Bolkow Gmbh Improvements in Rotor Assemblies for a Rotor Craft
US3545880A (en) * 1967-07-31 1970-12-08 Sud Aviat Soc Nationale De Con Rotor for rotary-wing aircraft
US3591310A (en) * 1968-07-04 1971-07-06 Sud Aviat Soc Nationale De Con Articulated hub for helicopter rotor
US3610774A (en) * 1968-10-30 1971-10-05 Sud Aviat Soc Nationale De Con Rotors for rotary-wing aircraft
US3679322A (en) * 1969-05-28 1972-07-25 Aerospatiale Rotor hubs on rotary wing aircraft
US3625634A (en) * 1969-12-10 1971-12-07 Gen Motors Corp Turbomachine rotor

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4195967A (en) * 1976-10-26 1980-04-01 Messerschmitt-Boelkow-Blohm Gmbh Rotor free of flapping hinges and free of lead-lag hinges
US4183718A (en) * 1976-12-11 1980-01-15 Messerschmitt-Bolkow-Blohm Gmbh Rotor for a rotary wing aircraft
US4264277A (en) * 1978-05-26 1981-04-28 The Boeing Company Redundant rotor blade retention system
US4516909A (en) * 1982-03-11 1985-05-14 Costruzioni Aeronautiche Giovanni Agusta S.P.A. Helicopter Rotor
US4521157A (en) * 1982-03-11 1985-06-04 Costruzioni Aeronautiche Giovanni Agusta S.P.A. Helicopter rotor hub
US4626173A (en) * 1983-03-18 1986-12-02 Societe Nationale Industrielle Et Aerospatiale Variable-pitch multi-blade propeller incorporating individually dismountable blades made of composite materials, process for manufacturing such blades and blades thus produced
US5340279A (en) * 1992-06-22 1994-08-23 United Technologies Corporation Snubber assembly for a rotor assembly having ducted, coaxial counter-rotating rotors
US20050079053A1 (en) * 2003-10-08 2005-04-14 Perkinson Robert H. Cyclic actuation system for a controllable pitch propeller and a method of providing aircraft control therewith
US6981844B2 (en) * 2003-10-08 2006-01-03 Hamilton Sundstrand Cyclic actuation system for a controllable pitch propeller and a method of providing aircraft control therewith
US20180002002A1 (en) * 2016-02-22 2018-01-04 Sikorsky Aircraft Corporation Rotor assembly including a one piece molding rotor hub

Also Published As

Publication number Publication date
GB1399704A (en) 1975-07-02
FR2156182A1 (enrdf_load_stackoverflow) 1973-05-25
DE2150741C3 (de) 1973-11-22
FR2156182B1 (enrdf_load_stackoverflow) 1976-08-20
DE2150741A1 (de) 1973-05-30
DE2150741B2 (de) 1973-05-03
IT968834B (it) 1974-03-20

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