CA2348677A1 - Rotor for rotary wing aircraft - Google Patents
Rotor for rotary wing aircraft Download PDFInfo
- Publication number
- CA2348677A1 CA2348677A1 CA 2348677 CA2348677A CA2348677A1 CA 2348677 A1 CA2348677 A1 CA 2348677A1 CA 2348677 CA2348677 CA 2348677 CA 2348677 A CA2348677 A CA 2348677A CA 2348677 A1 CA2348677 A1 CA 2348677A1
- Authority
- CA
- Canada
- Prior art keywords
- rotor
- spar
- blade
- blade housing
- tip
- 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
Links
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
Abstract
A rotor for rotary wing aircraft includes a number of features that reduce the collective forces required to control the pitch of the rotor. The spar caps of the spar become joined to one another at the same point where bonding begins between the blade and the spar. The tendency of blade to want to flatten out is minimized since the centrifugal force acting on the spar is located at or near the pitch change axis. Tip weights are located at or near the pitch change axis as well. In a preferred embodiment, the tip weights are located evenly in front of and behind the structural center of the inboard section of the spar. The blade of the rotor and the tip are not swept back.
Description
2 Cross-Reference to Related Applications 3 [0001] This application claims the priority of U.S. Provisional patent application serial 4 no. 60/206,661 filed May 24, 2000.
BACKGROUND OF THE INVENTION
6 Field of the Invention 7 [0002] The present invention relates generally to rotors for rotary wing aircraft.
8 Description of the Related Art 9 [0003] One type of rotor used for rotary wing aircraft is a single structural blade assembly made up of outer blades and internal spar caps. The rotor has a tip at either 11 extreme end. Each side of the blade of the rotor has a leading edge, that is moved into 12 the wind during rotation of the rotor and a trailing edge that lies opposite the leading 13 edge. Prior rotors, such as the one shown in U.S. Patent No. 6,024,325 encase two flex-14 beam spars within the rotor. Manipulation of the location and orientation of the spars alters the pitch of the rotor, thus permitting control of the aircraft's lift.
16 [0004] Centrifugal force tends to move all rotating masses toward the plane of rotation 17 because the plane of rotation represents the maximum distance that a mass can attain 18 from the axis of rotation. When a symmetrical rotor blade is at zero pitch relative to the 19 plane of rotation, every mass above the plane of rotation is matched by an equal mass on the lower side, so no pitch control forces are applied. However, when the rotor blade is 21 pitched up, such as when the pilot pulls up on the collective, masses near the leading edge 22 are moved above the plane of rotation and masses near the trailing edge are moved below 23 the plane of rotation. Centrifugal force tends to urge both masses toward the plane of 24 rotation, causing the blade to want to move toward zero pitch. Therefore, to minimize pitch control forces, all masses should be as close to the pitch change axis as possible.
26 (0005] U.S. Patent No. 6,024,325 describes a rotor for rotary wing aircraft. That patent 27 is incorporated herein by reference. The rotor described in the '325 patent provides a 1 tremendous improvement over prior ant rotors. However, some improvements are 2 desirable.
3 [0006] A prototype constructed in accordance with the '325 patent flew well, but the 4 collective forces were high. The large separation of the spar caps at the point of attachment to the blade increased collective control forces because centrifugal force 6 urged the spar caps toward the plane of rotation. Also, the rotor blade of the rotor 7 described in the '325 patent is swept back moving the outboard tip weights rearward to 8 eliminate compressive stresses in the trailing edge, thus, moving the center of gravity of 9 the tip weights toward the structural axis of the rotor. This sweep increases collective control forces because it increases the average distance of the tip weights away from the 11 pitch change axis as centrifugal force tends to push the weights toward the plane of 12 rotation. The sweep results in an aerodynamic "arrow" effect wherein the airstream on 13 the swept tip tends to force the blade toward zero pitch.
14 [0007] The present invention provides improvements over the prior art.
SUMMARY OF THE INVENTION
16 [0008] An object of the invention is to provide an improved rotor having lower 17 collective control forces while maintaining the advantages provided by prior art rotors.
18 A number of features are used to achieve this. First, the spar caps of the spar become 19 joined to one another at the same point where bonding begins between the blade and the spar. The tendency of blade to want to flatten out is minimized since centrifugal force 21 acting on the spar caps tries to force the caps to stay in the plane of rotation and by 22 placing the caps as close to the pitch axis as possible, reduces the moment arm and the 23 moment resisting the spar from twisting. Tip weights are located at or near the pitch 24 change axis as well. In a preferred embodiment, the tip weights are located evenly in front of and behind the structural center of the inboard section of the spar.
The blade of 26 the rotor and the tip are not swept back.
28 (0009] Figure 1 is a plan view of a portion of a prior art rotor. Figure 1 A (inset) is a 29 detail view of tip weights 16.
[0010] Figure 2 is a plan view of an exemplary rotor constructed in accordance with the 31 present invention. Figure 2A (inset) is a detail view of tip weights 80.
32 [0011] Figure 3 is a partial cut-away isometric view of the rotor shown in Figure 2.
1 [0012] Figure 4 is a cross-sectional view taken along lines 4-4 in Figure 3.
2 [0013] Figure 5 is a cross-sectional view taken along lines 5-5 in Figure 3.
3 [0014) Figure 6 is a cross-sectional view taken along lines 6-6 in Figure 3.
4 [0015) Figure 7 is a cross-sectional view taken along lines 7-7 in Figure 3.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
6 [0016) Referring first to Figure 1, half of prior art rotor 10 is shown of the type 7 described in U.S. Patent No. 6,024,325. The rotor 10 has an outer blade 12 with a spar 8 14 disposed therein. The blade 12 forms the aerodynamic housing of the rotor 10. Tip 9 weights 16 are located along the forward edge of a portion of the rotor I 0.
The spar 14 comprises two spar caps 18, 20 that are separated from one another proximate the root 11 of the rotor 10 and become joined to one another at approximately station 136. However, 12 bonding of the spar caps 18, 20 to the blade 12 occurs at station 84.5 and continues 13 outboard of that point. Therefore, the bonding occurs inboard of the point where the spar 14 caps 18, 20 become joined to one another. In addition, a structural rib 22 is disposed within the blades 12 at the point where bonding begins to further stiffen the rotor 10.
16 The rotor 10 may be considered to have an inboard portion 24 that lies radially inward 17 of the point where bonding begins. There is also an outboard portion 26. In the inboard 18 portion, the spar caps 14 are readily moveable upwardly and downwardly within the 19 blade 12 to one another in order to alter the pitch of the blade 12. In the outboard portion 26, the blade 12 is bonded to the spar caps 14. As a result, the spar caps 14 do not move 21 with respect to one another within the housing of the blade 12 in the outboard portion 26.
22 It should be appreciated that forces affecting pitch of the blade 12 are largely imparted 23 to the blade 12 at the point 28 where the outboard section 24 and inboard section 26 meet.
24 As can be seen, the spar caps 14 are widely separated from one another at point 28. Also, the tip of the blade 12 and spar are swept back.
26 [0017] The pitch change axis 30 for rotor 10 is shown on Figure 1. The pitch change 27 axis 30 is the axis around which the blade 12 will rotate when the pitch is changed by 28 movement of the spars 14. As can be seen, the majority of the tip weights 16, particularly 29 those proximate station 192, lie some distance behind the pitch change axis 30. Further, the nearer one gets to the blade tip 32, the further behind the axis 30 the weights 16 are 31 located. During rotation of the rotor 10, centrifugal forces acting on the mass of the I weights 16 will cause the weights 16 to want to move into the plane of rotation, thereby 2 increasing the collective forces necessary to increase the pitch of the blade 10.
3 [0018] Turning now to Figures 2, 3, 4, 5, 6 and 7 there is shown an exemplary rotor 50 4 that is constructed in accordance with the present invention. The pitch change axis 52 for rotor 50 is shown in Figure 2. The rotor 50 has two blade assemblies 54 and 56 that 6 extend outwardly from spinner 58. Because construction of the two blade assemblies 54, 7 56 is identical, only the construction of blade assembly 54 will be described in detail.
8 Stations along the blade assembly 54 are indicated by numerals in Figure 2.
As discussed 9 herein, stations refer to that position measured in inches from the axis of rotation 60 for the rotor 50. Dimensions given are for illustrative purposes only. The rotor 50 has a 11 unitary spar 62 that extends nearly tip-to-tip. The spar 62 is separated along its central 12 section into two spar caps 64, 66. The spar caps 64, 66 merge with one another to form 13 a single outboard spar portion 68. A blade cuff 69 is used to transfer pitch control forces 14 to the blade assembly 54 to twist the spar caps 64, 66. The blade assembly 54 has an outer blade housing 70 that is made up of an upper skin 72 and a lower skin 74 that, 16 collectively, form the airfoil surface for the rotor 50. The blade housing 70 is not swept 17 back, but the very outboard section is swept back like a shark fin to reduce noise. The 18 spar portion 68 is swept back a few degrees within the housing 70 proximate the tip 51.
19 (0019] Separation of the spar caps 64, 66 from one another is gradually reduced from the root, or axis of rotation 60 toward the station 114 of the rotor blade assembly 54. The 21 spar caps 64, 66 become joined to one another at approximately station 114.
A
22 reinforcing rib 76 is located at that station as well. Inboard of the rib 76, along inboard 23 portion 77, the spar caps 64, 66 are not bonded to the blade housing 70 so that they may 24 be moved upwardly and downwardly within the housing 70. Outboard of the rib 76, along outboard portion 79, the spar portion 68 is bonded to the blade housing 70 using 26 bonding material 78. As best shown in Figures 5, 6 and 7, bonding material 78 fills the 27 space between the spar portion 68 and the outer blade housing 70.
28 [0020] Tip weights 80 are disposed along the leading edge 82 of the blade assembly 54.
29 In the described embodiment, the tip weights 80 extend from station 184 outwardly to station 252. As can be seen with reference to Figure 2, the location of the tip weights 80 31 approximates the pitch change axis 52. In other words, the weights 80 are located to 32 minimize the average distance between the weights 80 and the pitch change axis 52. The 1 rearward sweep of the spar portion 68 proximate the tip 51 allows for this placement. The 2 rotor tip weights 80 are positioned near the leading edge 82 to keep the center of mass 3 ahead of the blade aerodynamic center. In a preferred embodiment, the tip weights 80 4 are located evenly in front of and behind the structural center of the inboard section of the spar 62.
6 [0021] In operation, the exemplary rotor 50 uses three primary features to reduce 7 collective control forces. First, separation of the spar caps 64, 66 gradually reduced from 8 the root 60 toward the tip 51 until the spar caps 64, 66 marry one another at the point 9 where the blade housing 70 is attached to the spar 62. Second, rotor tip weights 80 are attached to minimize the average distance between the weights 80 and the pitch change 11 axis 52 of the blade assembly 54. Third, the spar 62 is swept back proximate the tip 51 12 to follow the trailing edge of the tip weights 80. The aerodynamic shell of the blade 13 housing 70 is not swept.
14 [0022] While the invention has been described with reference to a preferred embodiment, it should be apparent to those skilled in the art that it is not so limited, but 16 is susceptible to various modifications and changes without departing from the scope of 17 the invention.
BACKGROUND OF THE INVENTION
6 Field of the Invention 7 [0002] The present invention relates generally to rotors for rotary wing aircraft.
8 Description of the Related Art 9 [0003] One type of rotor used for rotary wing aircraft is a single structural blade assembly made up of outer blades and internal spar caps. The rotor has a tip at either 11 extreme end. Each side of the blade of the rotor has a leading edge, that is moved into 12 the wind during rotation of the rotor and a trailing edge that lies opposite the leading 13 edge. Prior rotors, such as the one shown in U.S. Patent No. 6,024,325 encase two flex-14 beam spars within the rotor. Manipulation of the location and orientation of the spars alters the pitch of the rotor, thus permitting control of the aircraft's lift.
16 [0004] Centrifugal force tends to move all rotating masses toward the plane of rotation 17 because the plane of rotation represents the maximum distance that a mass can attain 18 from the axis of rotation. When a symmetrical rotor blade is at zero pitch relative to the 19 plane of rotation, every mass above the plane of rotation is matched by an equal mass on the lower side, so no pitch control forces are applied. However, when the rotor blade is 21 pitched up, such as when the pilot pulls up on the collective, masses near the leading edge 22 are moved above the plane of rotation and masses near the trailing edge are moved below 23 the plane of rotation. Centrifugal force tends to urge both masses toward the plane of 24 rotation, causing the blade to want to move toward zero pitch. Therefore, to minimize pitch control forces, all masses should be as close to the pitch change axis as possible.
26 (0005] U.S. Patent No. 6,024,325 describes a rotor for rotary wing aircraft. That patent 27 is incorporated herein by reference. The rotor described in the '325 patent provides a 1 tremendous improvement over prior ant rotors. However, some improvements are 2 desirable.
3 [0006] A prototype constructed in accordance with the '325 patent flew well, but the 4 collective forces were high. The large separation of the spar caps at the point of attachment to the blade increased collective control forces because centrifugal force 6 urged the spar caps toward the plane of rotation. Also, the rotor blade of the rotor 7 described in the '325 patent is swept back moving the outboard tip weights rearward to 8 eliminate compressive stresses in the trailing edge, thus, moving the center of gravity of 9 the tip weights toward the structural axis of the rotor. This sweep increases collective control forces because it increases the average distance of the tip weights away from the 11 pitch change axis as centrifugal force tends to push the weights toward the plane of 12 rotation. The sweep results in an aerodynamic "arrow" effect wherein the airstream on 13 the swept tip tends to force the blade toward zero pitch.
14 [0007] The present invention provides improvements over the prior art.
SUMMARY OF THE INVENTION
16 [0008] An object of the invention is to provide an improved rotor having lower 17 collective control forces while maintaining the advantages provided by prior art rotors.
18 A number of features are used to achieve this. First, the spar caps of the spar become 19 joined to one another at the same point where bonding begins between the blade and the spar. The tendency of blade to want to flatten out is minimized since centrifugal force 21 acting on the spar caps tries to force the caps to stay in the plane of rotation and by 22 placing the caps as close to the pitch axis as possible, reduces the moment arm and the 23 moment resisting the spar from twisting. Tip weights are located at or near the pitch 24 change axis as well. In a preferred embodiment, the tip weights are located evenly in front of and behind the structural center of the inboard section of the spar.
The blade of 26 the rotor and the tip are not swept back.
28 (0009] Figure 1 is a plan view of a portion of a prior art rotor. Figure 1 A (inset) is a 29 detail view of tip weights 16.
[0010] Figure 2 is a plan view of an exemplary rotor constructed in accordance with the 31 present invention. Figure 2A (inset) is a detail view of tip weights 80.
32 [0011] Figure 3 is a partial cut-away isometric view of the rotor shown in Figure 2.
1 [0012] Figure 4 is a cross-sectional view taken along lines 4-4 in Figure 3.
2 [0013] Figure 5 is a cross-sectional view taken along lines 5-5 in Figure 3.
3 [0014) Figure 6 is a cross-sectional view taken along lines 6-6 in Figure 3.
4 [0015) Figure 7 is a cross-sectional view taken along lines 7-7 in Figure 3.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
6 [0016) Referring first to Figure 1, half of prior art rotor 10 is shown of the type 7 described in U.S. Patent No. 6,024,325. The rotor 10 has an outer blade 12 with a spar 8 14 disposed therein. The blade 12 forms the aerodynamic housing of the rotor 10. Tip 9 weights 16 are located along the forward edge of a portion of the rotor I 0.
The spar 14 comprises two spar caps 18, 20 that are separated from one another proximate the root 11 of the rotor 10 and become joined to one another at approximately station 136. However, 12 bonding of the spar caps 18, 20 to the blade 12 occurs at station 84.5 and continues 13 outboard of that point. Therefore, the bonding occurs inboard of the point where the spar 14 caps 18, 20 become joined to one another. In addition, a structural rib 22 is disposed within the blades 12 at the point where bonding begins to further stiffen the rotor 10.
16 The rotor 10 may be considered to have an inboard portion 24 that lies radially inward 17 of the point where bonding begins. There is also an outboard portion 26. In the inboard 18 portion, the spar caps 14 are readily moveable upwardly and downwardly within the 19 blade 12 to one another in order to alter the pitch of the blade 12. In the outboard portion 26, the blade 12 is bonded to the spar caps 14. As a result, the spar caps 14 do not move 21 with respect to one another within the housing of the blade 12 in the outboard portion 26.
22 It should be appreciated that forces affecting pitch of the blade 12 are largely imparted 23 to the blade 12 at the point 28 where the outboard section 24 and inboard section 26 meet.
24 As can be seen, the spar caps 14 are widely separated from one another at point 28. Also, the tip of the blade 12 and spar are swept back.
26 [0017] The pitch change axis 30 for rotor 10 is shown on Figure 1. The pitch change 27 axis 30 is the axis around which the blade 12 will rotate when the pitch is changed by 28 movement of the spars 14. As can be seen, the majority of the tip weights 16, particularly 29 those proximate station 192, lie some distance behind the pitch change axis 30. Further, the nearer one gets to the blade tip 32, the further behind the axis 30 the weights 16 are 31 located. During rotation of the rotor 10, centrifugal forces acting on the mass of the I weights 16 will cause the weights 16 to want to move into the plane of rotation, thereby 2 increasing the collective forces necessary to increase the pitch of the blade 10.
3 [0018] Turning now to Figures 2, 3, 4, 5, 6 and 7 there is shown an exemplary rotor 50 4 that is constructed in accordance with the present invention. The pitch change axis 52 for rotor 50 is shown in Figure 2. The rotor 50 has two blade assemblies 54 and 56 that 6 extend outwardly from spinner 58. Because construction of the two blade assemblies 54, 7 56 is identical, only the construction of blade assembly 54 will be described in detail.
8 Stations along the blade assembly 54 are indicated by numerals in Figure 2.
As discussed 9 herein, stations refer to that position measured in inches from the axis of rotation 60 for the rotor 50. Dimensions given are for illustrative purposes only. The rotor 50 has a 11 unitary spar 62 that extends nearly tip-to-tip. The spar 62 is separated along its central 12 section into two spar caps 64, 66. The spar caps 64, 66 merge with one another to form 13 a single outboard spar portion 68. A blade cuff 69 is used to transfer pitch control forces 14 to the blade assembly 54 to twist the spar caps 64, 66. The blade assembly 54 has an outer blade housing 70 that is made up of an upper skin 72 and a lower skin 74 that, 16 collectively, form the airfoil surface for the rotor 50. The blade housing 70 is not swept 17 back, but the very outboard section is swept back like a shark fin to reduce noise. The 18 spar portion 68 is swept back a few degrees within the housing 70 proximate the tip 51.
19 (0019] Separation of the spar caps 64, 66 from one another is gradually reduced from the root, or axis of rotation 60 toward the station 114 of the rotor blade assembly 54. The 21 spar caps 64, 66 become joined to one another at approximately station 114.
A
22 reinforcing rib 76 is located at that station as well. Inboard of the rib 76, along inboard 23 portion 77, the spar caps 64, 66 are not bonded to the blade housing 70 so that they may 24 be moved upwardly and downwardly within the housing 70. Outboard of the rib 76, along outboard portion 79, the spar portion 68 is bonded to the blade housing 70 using 26 bonding material 78. As best shown in Figures 5, 6 and 7, bonding material 78 fills the 27 space between the spar portion 68 and the outer blade housing 70.
28 [0020] Tip weights 80 are disposed along the leading edge 82 of the blade assembly 54.
29 In the described embodiment, the tip weights 80 extend from station 184 outwardly to station 252. As can be seen with reference to Figure 2, the location of the tip weights 80 31 approximates the pitch change axis 52. In other words, the weights 80 are located to 32 minimize the average distance between the weights 80 and the pitch change axis 52. The 1 rearward sweep of the spar portion 68 proximate the tip 51 allows for this placement. The 2 rotor tip weights 80 are positioned near the leading edge 82 to keep the center of mass 3 ahead of the blade aerodynamic center. In a preferred embodiment, the tip weights 80 4 are located evenly in front of and behind the structural center of the inboard section of the spar 62.
6 [0021] In operation, the exemplary rotor 50 uses three primary features to reduce 7 collective control forces. First, separation of the spar caps 64, 66 gradually reduced from 8 the root 60 toward the tip 51 until the spar caps 64, 66 marry one another at the point 9 where the blade housing 70 is attached to the spar 62. Second, rotor tip weights 80 are attached to minimize the average distance between the weights 80 and the pitch change 11 axis 52 of the blade assembly 54. Third, the spar 62 is swept back proximate the tip 51 12 to follow the trailing edge of the tip weights 80. The aerodynamic shell of the blade 13 housing 70 is not swept.
14 [0022] While the invention has been described with reference to a preferred embodiment, it should be apparent to those skilled in the art that it is not so limited, but 16 is susceptible to various modifications and changes without departing from the scope of 17 the invention.
Claims (17)
1. A rotor for rotary wing aircraft having a pair of blade assemblies that extend outwardly from a rotor axis of rotation, each blade assembly comprising:
an inboard portion located outboard of the rotor axis of rotation, the inboard portion having an outer blade housing and a pair of separate spar caps extending therethrough, the spar caps not being bonded to the blade housing along the length of the inboard portion;
an outboard portion located outboard of the inboard portion, the outboard portion having an outer blade housing and a single spar portion extending therethrough, the single spar portion being bonded to the blade housing along substantially all of the length of the single spar portion; and a plurality of tip weights within the outboard portion of the blade housing.
an inboard portion located outboard of the rotor axis of rotation, the inboard portion having an outer blade housing and a pair of separate spar caps extending therethrough, the spar caps not being bonded to the blade housing along the length of the inboard portion;
an outboard portion located outboard of the inboard portion, the outboard portion having an outer blade housing and a single spar portion extending therethrough, the single spar portion being bonded to the blade housing along substantially all of the length of the single spar portion; and a plurality of tip weights within the outboard portion of the blade housing.
2. The rotor of claim 1 further comprising a reinforcing rib within the blade housing between the inboard and outboard portions.
3. The rotor of claim 2 wherein the spar caps are joined to one another at approximately the same station where the reinforcing rib is located.
4. The rotor of claim 3 wherein the spar caps are joined to each other at approximately station 114.
5. The rotor of claim 1 wherein the outer blade housing is not swept back proximate its outboard tip.
6. The rotor of claim 1 wherein said plurality of tip weights are located to substantially approximate a pitch change axis for the blade assembly.
7. The rotor of claim 6 wherein the tip weights are located substantially evenly in front of and behind the single spar portion.
8. A rotor for rotary wing aircraft having a pair of blade assemblies that extend outwardly from a rotor axis of rotation, each blade assembly comprising:
a longitudinal spar extending from the rotor axis of rotation, the spar comprising a pair of separate spar caps and a single spar portion formed by the merged spar caps;
a blade housing enclosing the longitudinal spar, the blade housing providing an aerodynamic airfoil for the blade assembly;
an outboard portion of the blade assembly wherein the single spar portion is bonded to the blade housing along its entire length; and a tip weight disposed along a forward edge of the outboard portion.
a longitudinal spar extending from the rotor axis of rotation, the spar comprising a pair of separate spar caps and a single spar portion formed by the merged spar caps;
a blade housing enclosing the longitudinal spar, the blade housing providing an aerodynamic airfoil for the blade assembly;
an outboard portion of the blade assembly wherein the single spar portion is bonded to the blade housing along its entire length; and a tip weight disposed along a forward edge of the outboard portion.
9. The rotor of claim 8 further comprising an inboard portion of the blade assembly wherein the pair of separate spar caps are not bonded to the blade housing along their entire length.
10. The rotor of claim 8 further comprising a reinforcing rib located within the blade housing and dividing the inboard portion from the outboard portion.
11. The rotor of claim 8 wherein the housing of the blade assembly is not swept rearwardly.
12. The rotor of claim 8 wherein the pair of separate spar caps merge with one another to form the single spar portion, said merging occurring at the location at which bonding of the single spar portion to the blade housing begins.
13. The rotor of claim 8 wherein the rotor blade assembly has a pitch change axis, and said tip weight is located substantially upon the pitch change axis.
14. A rotor for rotary wing aircraft that provides a pair of blade assemblies that extend outwardly from a rotor axis of rotation, the rotor comprising:
a longitudinal spar having a central portion that is secured to a hub, the central portion of the spar comprising a pair of separated spar caps that can be moved to control the pitch of the blade assemblies;
the spar further comprising distal single spar portions;
a blade housing that encloses the spar to form an airfoil, the blade housing having a plurality of tip weights retained within; and the blade housing being bonded to the single spar portions but not to the separate spar caps.
a longitudinal spar having a central portion that is secured to a hub, the central portion of the spar comprising a pair of separated spar caps that can be moved to control the pitch of the blade assemblies;
the spar further comprising distal single spar portions;
a blade housing that encloses the spar to form an airfoil, the blade housing having a plurality of tip weights retained within; and the blade housing being bonded to the single spar portions but not to the separate spar caps.
15. The rotor of claim 14 wherein the blade assembly has a pitch change axis and the tip weights are disposed proximate the pitch change axis.
16. The rotor of claim 14 wherein the distal single spar portions each have a rearwardly swept portion.
17. The rotor of claim 14 wherein no portion of the blade housing is swept rearwardly.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US20666100P | 2000-05-24 | 2000-05-24 | |
| US60/206,661 | 2000-05-24 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2348677A1 true CA2348677A1 (en) | 2001-11-24 |
Family
ID=22767381
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 2348677 Abandoned CA2348677A1 (en) | 2000-05-24 | 2001-05-24 | Rotor for rotary wing aircraft |
Country Status (2)
| Country | Link |
|---|---|
| CA (1) | CA2348677A1 (en) |
| GB (1) | GB2362865B (en) |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2912990B1 (en) * | 2007-02-23 | 2009-04-24 | Eurocopter France | ROTATING BLADE WITH RADIAL STRING AND AT LEAST ONE FRONT AND / OR REAR ARROW STRING |
| US9068559B2 (en) | 2009-02-16 | 2015-06-30 | Vestas Wind Systems A/S | Rotor blade for a wind turbine and a method for making the same |
| US8167570B2 (en) * | 2009-12-14 | 2012-05-01 | General Electric Company | Fluid turbine blade and method of providing the same |
| ES2623044T3 (en) | 2012-11-22 | 2017-07-10 | Airbus Operations S.L. | Method of manufacturing a highly integrated structure including leading and trailing edge ribs for an aircraft lift surface |
| US11174016B2 (en) | 2018-05-03 | 2021-11-16 | Jaunt Air Mobility, Llc | Compound rotorcraft with propeller |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2430354A1 (en) * | 1978-07-07 | 1980-02-01 | Aerospatiale | MULTIPALE PROPELLER WITH VARIABLE STEP OF A SIMPLIFIED TYPE |
| US6024325A (en) * | 1997-01-09 | 2000-02-15 | Cartercopters, Llc | Rotor for rotary wing aircraft |
-
2001
- 2001-05-24 GB GB0112590A patent/GB2362865B/en not_active Expired - Lifetime
- 2001-05-24 CA CA 2348677 patent/CA2348677A1/en not_active Abandoned
Also Published As
| Publication number | Publication date |
|---|---|
| GB2362865B (en) | 2004-11-10 |
| GB2362865A (en) | 2001-12-05 |
| GB0112590D0 (en) | 2001-07-18 |
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| Date | Code | Title | Description |
|---|---|---|---|
| EEER | Examination request | ||
| FZDE | Dead |