US3750982A - Rotary wing aircraft - Google Patents

Rotary wing aircraft Download PDF

Info

Publication number
US3750982A
US3750982A US00221610A US3750982DA US3750982A US 3750982 A US3750982 A US 3750982A US 00221610 A US00221610 A US 00221610A US 3750982D A US3750982D A US 3750982DA US 3750982 A US3750982 A US 3750982A
Authority
US
United States
Prior art keywords
rotor
hinge
blade
helicopter
central section
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
US00221610A
Other languages
English (en)
Inventor
J Gear
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.)
Individual
Original Assignee
Individual
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 Individual filed Critical Individual
Application granted granted Critical
Publication of US3750982A publication Critical patent/US3750982A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B64—AIRCRAFT; AVIATION; COSMONAUTICS
    • B64C—AEROPLANES; HELICOPTERS
    • B64C27/00—Rotorcraft; Rotors peculiar thereto
    • B64C27/32—Rotors
    • B64C27/46—Blades
    • B64C27/473—Constructional features
    • B64C27/50—Blades foldable to facilitate stowage of aircraft
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B64—AIRCRAFT; AVIATION; COSMONAUTICS
    • B64C—AEROPLANES; HELICOPTERS
    • B64C27/00—Rotorcraft; Rotors peculiar thereto
    • B64C27/54—Mechanisms for controlling blade adjustment or movement relative to rotor head, e.g. lag-lead movement

Definitions

  • ABSTRACT A means for folding a helicopter rotor blade includes a generally chordwise hinge located intermediate the root and tip ends of the blade, the outboard portion of the blade being rotatable about the hinge to a folded position in which it overlaps the inboard portion of the blade along at least part of its length.
  • the hinge is formed in a generally cylindrical hollow member of aerofoil shape having leading and trailing sections and a rotatable central section. The inboard portion is secured to the leading and trailing sections, and the outboard portion is secured to the rotatable central section.
  • An arm formed integral with the central section abuts a surface formed in the inboard portion of the rotor blade adjacent the hinge when the outboard portion of the rotor blade is in its fully extended position.
  • the hinge is locked and unlocked by a ram which, when extended, locates through mating holes in the arm and the abutting surface.
  • Existing power folding arrangements usually comprise hinges mounted adjacent the rotor head about which all blades are folded in a generally rearward direction to lie either above or adjacent the fuselage and tail cone, the folded length being further reduced by folding the rearmost extremity of the tail cone forwardly.
  • This means that the folded length must be at least the sum of a blade length plus the length of the fuselage forward of the rotor head, and has resulted in severe limitations in the size of helicopters designed for operation and storage in confined spaces such as encountered in shipborne operations.
  • Designers have been forced to limit the size of rotor blades to that capable of being folded into an available space and have not been free to design a rotor system whose diameter is determined solely by an optimisation based on flight considerations. This type of folding arrangement results frequently in a reduction in length between the flying length and the folded length of approximately 30 per cent.
  • a further disadvantage with known systems is that the operating mechanisms are very complicated and heavy and have an unclean aerodynamic shape which results in reliability and maintenance problems and imposes serious operational limitations, due to the weight penalty and high drag characteristics.
  • a rotor blade having a root end and a tip end, the root end being adapted for connection to a rotor head, and a generally chordwise extending hinge located intermediate the root and tip ends thereof to separate the blade into inboard and outboard portions, the outboard portion being foldable about the hinge to a position in which it overlaps the inboard portion along at least part of its length, wherein the hinge is formed in a generally cylindrical hollow member of aerofoil shape having leading and trailing sections and a rotatable central section.
  • FIG. I is a plan view of a helicopter with its rotor blades extended
  • FIG. 2 is a plan view of the same helicopter with its rotorblades and fuselage folded
  • FIG. 3 is a side view of FIG. 2, in which two of the rotor blades have been omitted for clarity,
  • FIG. 4 is a plan view of one suitable mechanism .for folding the blades in which parts are broken away to show more detail
  • FIG. 5 is a sectional view on line A-A of FIG. 4, and
  • FIG. 6 is a view on arrow B of FIG. 4.
  • a helicopter has a fuselage 11 and an aerofoil member in the form of a stub wing 12 extending from each side of the fuselage.
  • the wing 12 houses two engines 13 connected through a suitable transmission system 14 to drive a rotor system which includes a rotor head 15 and four rotor blades 16, marked C, D, E and F.
  • the root end 17 of each blade is secured to the rotor head 15 by any of a number of suitable methods well known to persons skilled in the art, and extends radially outwardly from the root end to terminate at the tip end 18.
  • a conventional tail rotor assembly 20 is located at the rear of the fuselage 11.
  • a hollow bullet-shaped member 19 is located chordwise of the blade intermediate the :root and tip ends and includes a hinge about which the tip end can fold and also a housing for an operating mechanism for mechanically completing the folding operation.
  • the member 19 is approximately 9 inches in diameter and is located at approximately one third of the blade radius. Details of the member 19 and the operating mechanism are shown in FIGS. 4, 5 and 6, and will be described later in the specification.
  • the members 19 are located at an angle other than normal to the longitudi nal axis of their respective blades, the angle being shown as approximately 7 in FIG. 4. This ensures that when the tip end 18 is folded to the position shown in FIG. 2 it does not foul the rotor head 15 but does in fact lie tangential to it.
  • the member I9 comprises a leading section 21, a trailing section 22 and a central section 23 which is rotatable relative to the leading and trailing sections 21 and 22 about a hinge centreline 41.
  • Flanges 24 formed on the inboard portion 25 of the rotor blade are secured by two bolts 26 to a flange 27 which is secured to the leading and trailing sections 21 and 22 of the member 19.
  • Flanges 28 formed on the outboard portion 29 of the rotor blade are secured by bolts 30 to a flange 31 formed integral with the central rotatable portion 23 of the member 19. In thisway the member 19 provides a hinge about-which the outboard portion 29 of the rotor blade can rotate with respect to the inboard portion 25.
  • a moulding 32 of aerofoil shape corresponding to the rotor blade is located between the inboard portion 25 of the rotor blade and the member 19, and is bonded to the leading and trailing sections 21 and 22.
  • a moulding 33 of similar aerofoil shape is located between the outboard portion 29 of the rotor blade and the member 19, and is bonded to the outboard portion 29 of the blade.
  • An electric motor 37 is secured within the central area of the member 19 and is arranged to rotate the central section 23 through a high ratio reduction gearing 38 arranged concentricallyabout the motor 37 and the hinge centreline 41 and splines 39 formed on the inner diameter of the central section 23. It will be clear, therefore, that energisation of the motor 37 causes rotation of the central section 23, which in turn rotates the outboard portion 29 of the rotor blade about the hinge centreline 41.
  • the reduction ratio between the motor and the blade drive is over 6,000 to 1; however, it is to be understood that this ratio can be varied within wide limits to suit other designs.
  • Reduction ratios of this order mean that a small lightweight .motor can be used, a two horsepower unit being chosen for the particular embodiment described.
  • An arm 34 (FIG. 5) formed integral with the central rotatable section 23 is arranged so that when the rotor blade is in the extended position (FIGS. 3, 4 and 5), the
  • a blade lock actuator 35 is housed in the inboard portion 25 of the rotor blade and arranged so that when a ram 36 is extended from the actuator 35 it locates in mating holes formed in the arm 34 and the flange 24 to effectively lock the blade in the extended position.
  • the blade lock actuator 35 may be either electrically, pneumatically, or hydraulically operated; however, it is obviously convenient to operate the motor 37 and the actuator 35 by the same medium.
  • the rotor head When it is required to fold the rotor blades according to the present invention, the rotor head is positioned so that each of the four rotor blades 16 extends at an angle of approximately 45 to the longitudinal centreline of the fuselage.
  • the ram 36 is retracted by the actuator 35 to unlock the outer portion 29 from the inner portion 25.
  • the electric motor 37 is energised and acts through the reduction gearing 38 to rotate the outer portion 29 about the hinge in a direction initially upwardly and through an arc of approximately 180 to the overlapping folded position shown in FIGS. 2 and 3.
  • the pair of blades E and F only are shown to more clearly illustrate the folded overlapping configuration of the blades on one side of the helicopter, the other pair of blades C and D moving to a similar configuration on the other side, as shown in plan in FIG. 2.
  • the blades are moved in pairs through their up and down" movement, commencing with pair C and E followed by pair D and F, blades C and F moving in a generally rearward direction and blades D and E moving in a generally forward direction.
  • the order of folding can be automatic by arranging sequential operation of the blade lock actuators 35 and the motors 37, and limit switches are incorporated to de-energise the motor when the blade reaches its extended and folded positions.
  • the folding arrangement disclosed eliminates the need to lock the blade in pitch during the folding operation, which avoids the excessive loads placed on the flight controls during folding by conventional methods.
  • a rotor blade having a root end and a tip end, the root end being adapted for connection to a rotor head, and a generally chordwise extending hinge located intermediate the root and tip ends thereof to separate the blade into inboard and outboard portions, the outboard portion being foldable about the hinge to a position in which it overlaps the inboard portion along at least part of its length, wherein the hinge is formed in a generally cylindrical hollow member of aerofoil shape having leading and trailing sections and a rotatable central section.
  • a rotor blade as claimed in claim 2 wherein an arm formed integral with the central section is arranged so that, when the outboard portion of the rotor blade is in its fully extended position, the arm extends inwardly to abut a surface formed in the inboard portion of the rotor blade adjacent the hinge.
  • a helicopter having a fuselage and at least one power source arranged to drive a main rotor system, the rotor system including a rotor head and a plurality of rotor blades as claimed in claim 4.
  • a rotor blade as claimed in claim 2 wherein a motor is located in the hollow hinge member to drive a high ratio reduction unit arranged coincidental with the hinge centreline, the output of the reduction unit mating with splines on the internal diameter of the central rotatable section to rotate the central section relative the leading and trailing sections.
  • a helicopter having a fuselage and at least one power source arranged to drive a main rotor system, the rotor system including a rotor head and a plurality or rotor blades as claimed in claim 6.
  • a helicopter having a fuselage and at least one power source arranged to drive a main rotor system, the rotor system including a rotor head and a plurality of rotor blades as claimed in claim 2.

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Aviation & Aerospace Engineering (AREA)
  • Structures Of Non-Positive Displacement Pumps (AREA)
  • Transmission Devices (AREA)
  • Pivots And Pivotal Connections (AREA)
  • Toys (AREA)
US00221610A 1971-02-05 1972-01-28 Rotary wing aircraft Expired - Lifetime US3750982A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB401171 1971-02-05

Publications (1)

Publication Number Publication Date
US3750982A true US3750982A (en) 1973-08-07

Family

ID=9769083

Family Applications (1)

Application Number Title Priority Date Filing Date
US00221610A Expired - Lifetime US3750982A (en) 1971-02-05 1972-01-28 Rotary wing aircraft

Country Status (4)

Country Link
US (1) US3750982A (en:Method)
CA (1) CA975341A (en:Method)
FR (1) FR2124474B1 (en:Method)
GB (1) GB1333852A (en:Method)

Cited By (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3802798A (en) * 1973-01-30 1974-04-09 Us Air Force Rotor blade capturing assembly
US3921938A (en) * 1973-08-28 1975-11-25 Westland Aircraft Ltd Helicopters
US4071206A (en) * 1976-09-20 1978-01-31 Aerospace General Co. Portable helicopter
US4466775A (en) * 1981-11-19 1984-08-21 Westland Plc Helicopter rotors
US5915649A (en) * 1996-08-23 1999-06-29 Mcdonnell Douglas Helicopter Company Roadable helicopter
US20060157614A1 (en) * 2003-01-22 2006-07-20 John Simpson Wing for a compound helicopter
US20090081043A1 (en) * 2007-09-25 2009-03-26 The Boeing Company Folding rotor for an autogyro device
KR101083731B1 (ko) 2004-09-20 2011-11-16 한국항공우주산업 주식회사 헬리콥터
US20130175386A1 (en) * 2012-01-06 2013-07-11 Deutsches Zentrum Fur Luft- Und Raumfahrt E.V. Helicopter configuration
US9475578B2 (en) 2013-12-10 2016-10-25 Airbus Helicopters Deutschland GmbH Rotary wing aircraft with a tail shroud
US9592910B1 (en) * 2015-12-18 2017-03-14 Amazon Technologies, Inc. Geometrically reconfigurable propellers
US10287006B1 (en) 2015-12-18 2019-05-14 Amazon Technologies, Inc. Adjustable propeller blades for sound control
US10370098B1 (en) 2015-12-18 2019-08-06 Amazon Technologies, Inc. Adjustable propeller blade with sound flaps
WO2020190126A1 (en) * 2019-03-18 2020-09-24 Pal-V Ip B.V. Rotor blades of a lift rotor

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
ZA201305905B (en) * 2012-08-07 2014-04-30 Epsilon Eng Services (Pty) Ltd A hinge arrangement

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2815820A (en) * 1955-04-19 1957-12-10 Gyrodyne Company Of America In Power folding rotor blade system for rotary wing aircraft
US2941604A (en) * 1956-11-05 1960-06-21 Ira J Marriage Blade structure for airplane propellers

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2815820A (en) * 1955-04-19 1957-12-10 Gyrodyne Company Of America In Power folding rotor blade system for rotary wing aircraft
US2941604A (en) * 1956-11-05 1960-06-21 Ira J Marriage Blade structure for airplane propellers

Cited By (21)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3802798A (en) * 1973-01-30 1974-04-09 Us Air Force Rotor blade capturing assembly
US3921938A (en) * 1973-08-28 1975-11-25 Westland Aircraft Ltd Helicopters
US4071206A (en) * 1976-09-20 1978-01-31 Aerospace General Co. Portable helicopter
US4466775A (en) * 1981-11-19 1984-08-21 Westland Plc Helicopter rotors
US5915649A (en) * 1996-08-23 1999-06-29 Mcdonnell Douglas Helicopter Company Roadable helicopter
US20060157614A1 (en) * 2003-01-22 2006-07-20 John Simpson Wing for a compound helicopter
KR101083731B1 (ko) 2004-09-20 2011-11-16 한국항공우주산업 주식회사 헬리콥터
US20090081043A1 (en) * 2007-09-25 2009-03-26 The Boeing Company Folding rotor for an autogyro device
US7985048B2 (en) * 2007-09-25 2011-07-26 The Boeing Company Folding rotor for an autogyro device
US8807476B2 (en) * 2012-01-06 2014-08-19 Deutsches Zentrum Fur Luft-Und Raumfahrt E.V. Helicopter with oblique tail boom
US20130175386A1 (en) * 2012-01-06 2013-07-11 Deutsches Zentrum Fur Luft- Und Raumfahrt E.V. Helicopter configuration
US9475578B2 (en) 2013-12-10 2016-10-25 Airbus Helicopters Deutschland GmbH Rotary wing aircraft with a tail shroud
US9592910B1 (en) * 2015-12-18 2017-03-14 Amazon Technologies, Inc. Geometrically reconfigurable propellers
US10179646B1 (en) 2015-12-18 2019-01-15 Amazon Technologies, Inc. Reconfiguring propellers during aerial vehicle operation
US10287006B1 (en) 2015-12-18 2019-05-14 Amazon Technologies, Inc. Adjustable propeller blades for sound control
US10370098B1 (en) 2015-12-18 2019-08-06 Amazon Technologies, Inc. Adjustable propeller blade with sound flaps
US10822077B1 (en) 2015-12-18 2020-11-03 Amazon Technologies, Inc. Geometrically reconfigurable propellers
US11161604B1 (en) * 2015-12-18 2021-11-02 Amazon Technologies, Inc. Anti-sound production using adjustable propeller blades
WO2020190126A1 (en) * 2019-03-18 2020-09-24 Pal-V Ip B.V. Rotor blades of a lift rotor
CN113573979A (zh) * 2019-03-18 2021-10-29 帕尔夫知识产权私人有限公司 提升转子的转子叶片
CN113573979B (zh) * 2019-03-18 2025-07-25 帕尔夫知识产权私人有限公司 提升转子的转子叶片

Also Published As

Publication number Publication date
DE2204619B2 (de) 1977-04-07
FR2124474B1 (en:Method) 1977-11-10
DE2204619A1 (de) 1972-09-21
CA975341A (en) 1975-09-30
GB1333852A (en) 1973-10-17
FR2124474A1 (en:Method) 1972-09-22

Similar Documents

Publication Publication Date Title
US3750982A (en) Rotary wing aircraft
US4427168A (en) Variable camber leading edge mechanism with Krueger flap
US3797783A (en) Convertiplane
US8376264B1 (en) Rotor for a dual mode aircraft
JP6630286B2 (ja) 旋回する回転翼及び収容される回転翼羽根を有する空気力学的に効率の良い軽量の垂直離着陸航空機
US3592412A (en) Convertible aircraft
US4398688A (en) Leading edge flap for an airfoil
JP6584801B2 (ja) 折り畳み可能な翼型をラッチングする及びロックするためのシステム
US5743489A (en) Aircraft with two alternatingly operated propellers of different radius
EP3575203B1 (en) An aircraft wing and wing tip device
US6065933A (en) Folding rotor blade/propeller drive and pitch control actuator
US5992796A (en) Secondary wing system for use on an aircraft
US7137589B2 (en) Compound helicopter with combined wings and landing struts
US12234011B2 (en) Convertiplane with stopped rotors, and repositionable rotor blades
US3363859A (en) Aircraft
WO1990001002A1 (en) Helicopter rotor blades
US3484175A (en) Means and method of synchronously folding helicopter blades
US3121544A (en) Safety and high lift system and apparatus for aircraft
US3900176A (en) Aircraft
US3253805A (en) Aircraft having a substantially annular wing thereon
CN113518746B (zh) 用于飞行器的推进系统
US3744742A (en) Rotary wing aircraft with folding rotor blades
JPH03292294A (ja) 垂直離着陸航空機
US3438447A (en) Dual linear output and dual rotary output actuator with redundant drive
US3494707A (en) Convertiplane