US3754840A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Composite helicopter rotor and blade
Assignee: RTX Corp
•
Filing: 1972-05-31
•
Granted: 1973-08-28
•
Expires: 1992-05-31
Abstract
Abstract A composite helicopter rotor and balde is produced by building the blade around a selectively fabricated structural spar which includes a central filler member and a plurality of fiber members commencing at the blade tip, extending substantially for its full length to the blade root, extending therebeyond and then folding back upon itself to form a loop, and then extending along the other side of the filler member to substantially the tip of the blade again and being bonded to the opposite sides of the filler member. The spar is then bonded on both upper and lower spar surfaces to the blade cuff attachment member, which includes a pin about which the loop is formed. Redundant retention therefore occurs through either of the bond areas between the cuff attachment member and the fiber members, and by means of the pintype member. Preferably the fiber members are unidirectional. Additional layers of fiber members are wrapped around the spar at its root end and extend in various directions on opposite sides of the blade so as to form a cylindrical or oval shaped boot to carry blade torsional loads.
Inventors
- 👤 R Zincone
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 00:24
CPC Classifications
B; B64; B64C; B64C27/00; B64C27/32; B64C27/46; B64C27/473; B64C2027/4733; B64C2027/4736; Y; Y10; Y10T; Y10T428/00; Y10T428/24; Y10T428/24149
Claims Analysis
Total Claims: 151
Claim 1
Independent Claim
187 words
A composite helicopter blade having: A. a structural spar including: 1. a central lightweight filler member extending along the blade span between substantially the blade root and the blade tip, 2. a plurality of high strength fiber members extending between the blade tip on one side of said filler member to the blade root and therebeyond and then doubling back so as to form a loop and then extending from the blade root to the blade tip on the opposite side of said filler member and being bonded to said filler member on both sides thereof throughout substantially the full span dimension of the filler member, B. means adapted to connect said structural spar to a rotor including: 1. a first member bonded to the exterior of said fiber members on one side of said filler member, 2. a second member bonded to the exterior of said fiber members on the opposite side of said filler member, 3. a pin member extending through said loop in said fiber members, and 4. means adapted to connect said first and second members and said pin member to the rotor.
Claim 2
Dependent Claim
187 words
A composite helicopter blade having: A. a structural spar including: 1. a central lightweight filler member extending along the blade span between substantially the blade root and the blade tip, 2. a plurality of high strength fiber members extending between the blade tip on one side of said filler member to the blade root and therebeyond and then doubling back so as to form a loop and then extending from the blade root to the blade tip on the opposite side of said filler member and being bonded to said filler member on both sides thereof throughout substantially the full span dimension of the filler member, B. means adapted to connect said structural spar to a rotor including: 1. a first member bonded to the exterior of said fiber members on one side of said filler member, 2. a second member bonded to the exterior of said fiber members on the opposite side of said filler member, 3. a pin member extending through said loop in said fiber members, and 4. means adapted to connect said first and second members and said pin member to the rotor.
Claim 3
Dependent Claim
87 words
a plurality of high strength fiber members extending between the blade tip on one side of said filler member to the blade root and therebeyond and then doubling back so as to form a loop and then extending from the blade root to the blade tip on the opposite side of said filler member and being bonded to said filler member on both sides thereof throughout substantially the full span dimension of the filler member, B. means adapted to connect said structural spar to a rotor including:
Claim 4
Dependent Claim
87 words
a plurality of high strength fiber members extending between the blade tip on one side of said filler member to the blade root and therebeyond and then doubling back so as to form a loop and then extending from the blade root to the blade tip on the opposite side of said filler member and being bonded to said filler member on both sides thereof throughout substantially the full span dimension of the filler member, B. means adapted to connect said structural spar to a rotor including:
Claim 5
Dependent Claim
19 words
a second member bonded to the exterior of said fiber members on the opposite side of said filler member,
Claim 6
Dependent Claim
19 words
a second member bonded to the exterior of said fiber members on the opposite side of said filler member,
Claim 7
Dependent Claim
48 words
A blade according to claim 1 and including: A. additional filler material of selected shape and connected to said spar to cooperate therewith in forming the blade cross-sectional shape, and B. a skin member enveloping said spar and said additional filler material to produce a smooth blade surface.
Claim 8
Dependent Claim
68 words
a plurality of high strength fiber members of substantially U-shaped cross section with the two legs thereof extending substantially between the blade tip end and the blade root end and bonded to said filler member and with the curved portion of the U forming a loop extending beyond the blade root end of said filler member, B. means adapted to connect said structural spar to a rotor including:
Claim 9
Dependent Claim
68 words
a plurality of high strength fiber members of substantially U-shaped cross section with the two legs thereof extending substantially between the blade tip end and the blade root end and bonded to said filler member and with the curved portion of the U forming a loop extending beyond the blade root end of said filler member, B. means adapted to connect said structural spar to a rotor including:
Claim 10
Dependent Claim
12 words
a second means bonded to the other leg of said fiber members,
Claim 11
Dependent Claim
12 words
a second means bonded to the other leg of said fiber members,
Claim 12
Dependent Claim
63 words
a plurality of high strength fiber members of substantially U-shaped cross section with the two legs thereof extending substantially between the blade tip end and the blade root end and bonded to said filler member and with the curved portion of the U forming the loop extending beyond the blade root end of said filler member, B. a blade root cuff membering including:
Claim 13
Dependent Claim
63 words
a plurality of high strength fiber members of substantially U-shaped cross section with the two legs thereof extending substantially between the blade tip end and the blade root end and bonded to said filler member and with the curved portion of the U forming the loop extending beyond the blade root end of said filler member, B. a blade root cuff membering including:
Claim 14
Dependent Claim
12 words
a second means bonded to the other leg of saiD fiber members,
Claim 15
Dependent Claim
12 words
a second means bonded to the other leg of saiD fiber members,
Claim 16
Dependent Claim
15 words
a second means bonded to the other side of said loop in said fiber members,
Claim 17
Dependent Claim
15 words
a second means bonded to the other side of said loop in said fiber members,
Claim 18
Dependent Claim
60 words
a plurality of continuous, high strength fiber members extending substantially between the blade tip end of said filler member to the blade root end thereof and connected to said filler member throughout and shaped to form a loop extending beyond the blade root end of said filler member, B. means adapted to connect said structural spar to a rotor including:
Claim 19
Dependent Claim
60 words
a plurality of continuous, high strength fiber members extending substantially between the blade tip end of said filler member to the blade root end thereof and connected to said filler member throughout and shaped to form a loop extending beyond the blade root end of said filler member, B. means adapted to connect said structural spar to a rotor including:
Claim 20
Dependent Claim
19 words
a second member bonded to the exterior of said fiber members on the opposite side of said filler member,
Claim 21
Dependent Claim
19 words
a second member bonded to the exterior of said fiber members on the opposite side of said filler member,
Claim 22
Dependent Claim
99 words
a plurality of continuous, high strength fiber members extending between the blade tip on one side of said filler member to the blade root and therebeyond and then doubling back so as to form a loop and then extending from the blade root to the blade tip on the opposite side of said filler member and being bonded to said filler member on both sides thereof throughout substantially the full span dimension of the filler member, B. additional filler material of selected shape and connected to said spar to cooperate therewith in forming the blade cross-sectional shape and including:
Claim 23
Dependent Claim
99 words
a plurality of continuous, high strength fiber members extending between the blade tip on one side of said filler member to the blade root and therebeyond and then doubling back so as to form a loop and then extending from the blade root to the blade tip on the opposite side of said filler member and being bonded to said filler member on both sides thereof throughout substantially the full span dimension of the filler member, B. additional filler material of selected shape and connected to said spar to cooperate therewith in forming the blade cross-sectional shape and including:
Claim 24
Dependent Claim
16 words
a second member bonded to said fiber members on the opposite side of said filler member,
Claim 25
Dependent Claim
16 words
a second member bonded to said fiber members on the opposite side of said filler member,
Claim 26
Dependent Claim
82 words
a plurality of high strength fiber members extending between the blade tip on one side of said filler member to the blade root and therebeyond and then doubling back so as to form a loop and then extending from the blade root to the blade tip on the opposite side of said filler member and being bonded to said filler member on both sides thereof throughout substantially the full span dimension of the filler member, B. a blade root cuff member including:
Claim 27
Dependent Claim
82 words
a plurality of high strength fiber members extending between the blade tip on one side of said filler member to the blade root and therebeyond and then doubling back so as to form a loop and then extending from the blade root to the blade tip on the opposite side of said filler member and being bonded to said filler member on both sides thereof throughout substantially the full span dimension of the filler member, B. a blade root cuff member including:
Claim 28
Dependent Claim
24 words
a second blade cuff extension member overlapping the blade spar and bonded to said fiber members on the opposite side of said filler member,
Claim 29
Dependent Claim
24 words
a second blade cuff extension member overlapping the blade spar and bonded to said fiber members on the opposite side of said filler member,
Claim 30
Dependent Claim
68 words
a plurality of high strength fiber members of substantially U-shaped cross section with the two legs thereof extending substantially between the blade tip end and the blade root end and bonded to said filler member and with the curved portion of the U forming a loop extending beyond the blade root end of said filler member, B. means adapted to connect said structural spar to a rotor including:
Claim 31
Dependent Claim
68 words
a plurality of high strength fiber members of substantially U-shaped cross section with the two legs thereof extending substantially between the blade tip end and the blade root end and bonded to said filler member and with the curved portion of the U forming a loop extending beyond the blade root end of said filler member, B. means adapted to connect said structural spar to a rotor including:
Claim 32
Dependent Claim
8 words
a second means bonded to said fiber members,
Claim 33
Dependent Claim
8 words
a second means bonded to said fiber members,
Claim 34
Dependent Claim
14 words
a second member bonded to the other leg of the U of said member.
Claim 35
Dependent Claim
14 words
a second member bonded to the other leg of the U of said member.
Claim 36
Dependent Claim
15 words
a second member bonded to the other leg of thE U of said composite member.
Claim 37
Dependent Claim
15 words
a second member bonded to the other leg of thE U of said composite member.
Claim 38
Dependent Claim
13 words
a second means bonded to the other leg of said fiber composite members,
Claim 39
Dependent Claim
13 words
a second means bonded to the other leg of said fiber composite members,
Claim 40
Dependent Claim
15 words
a second means bonded to the other side of said loop in said fiber members,
Claim 41
Dependent Claim
15 words
a second means bonded to the other side of said loop in said fiber members,
Claim 42
Dependent Claim
19 words
a second member bonded to the exterior of said fiber members on the opposite side of said filler member,
Claim 43
Dependent Claim
19 words
a second member bonded to the exterior of said fiber members on the opposite side of said filler member,
Claim 44
Dependent Claim
94 words
a plurality of continuous, high strength fiber members extending between the blade tip on one of said sides of said filler member to the blade root and therebeyond and then doubling back so as to form a loop and then extending from the blade root to the blade tip on the opposite of said sides of said filler member and being bonded to said filler member on both of said sides thereof throughout substantially the full span dimension of the filler member, B. means adapted to connect said structural spar to a rotor including:
Claim 45
Dependent Claim
94 words
a plurality of continuous, high strength fiber members extending between the blade tip on one of said sides of said filler member to the blade root and therebeyond and then doubling back so as to form a loop and then extending from the blade root to the blade tip on the opposite of said sides of said filler member and being bonded to said filler member on both of said sides thereof throughout substantially the full span dimension of the filler member, B. means adapted to connect said structural spar to a rotor including:
Claim 46
Dependent Claim
19 words
a second member bonded to the exterior of said fiber members on the opposite side of said filler member,
Claim 47
Dependent Claim
19 words
a second member bonded to the exterior of said fiber members on the opposite side of said filler member,
Claim 48
Dependent Claim
27 words
a second blade cuff extension member overlapping the blade spar and bonded to the exterior of said fiber members on the opposite side of said filler member,
Claim 49
Dependent Claim
27 words
a second blade cuff extension member overlapping the blade spar and bonded to the exterior of said fiber members on the opposite side of said filler member,
Claim 50
Dependent Claim
82 words
a plurality of high strength fiber members extending between the blade tip on one side of said filler member to the blade root and therebeyond and then doubling bacK so as to form a loop and then extending from the blade root to the blade tip on the opposite side of said filler member and being bonded to said filler member on both sides thereof throughout substantially the full span dimension of the filler member, B. a blade root cuff member including:
Claim 51
Dependent Claim
82 words
a plurality of high strength fiber members extending between the blade tip on one side of said filler member to the blade root and therebeyond and then doubling bacK so as to form a loop and then extending from the blade root to the blade tip on the opposite side of said filler member and being bonded to said filler member on both sides thereof throughout substantially the full span dimension of the filler member, B. a blade root cuff member including:
Claim 52
Dependent Claim
72 words
a plurality of continuous, high strength fiber members extending substantially between the blade tip end of said filler member to the blade root end thereof and connected to said filler member throughout and shaped to form a loop extending beyond the blade root end of said filler member, B. additional filler material of selected shape and connected to said spar to cooperate therewith in forming the blade cross sectional shape and including:
Claim 53
Dependent Claim
72 words
a plurality of continuous, high strength fiber members extending substantially between the blade tip end of said filler member to the blade root end thereof and connected to said filler member throughout and shaped to form a loop extending beyond the blade root end of said filler member, B. additional filler material of selected shape and connected to said spar to cooperate therewith in forming the blade cross sectional shape and including:
Claim 54
Dependent Claim
15 words
a second means bonded to the other side of said loop in said fiber members,
Claim 55
Dependent Claim
15 words
a second means bonded to the other side of said loop in said fiber members,
Claim 56
Dependent Claim
87 words
a plurality of high strength fiber members extending beTween the blade tip on one side of said filler member to the blade root and therebeyond and then doubling back so as to form a loop and then extending from the blade root to the blade tip on the opposite side of said filler member and being bonded to said filler member on both sides thereof throughout substantially the full span dimension of the filler member, B. means adapted to connect said structural spar to a rotor including:
Claim 57
Dependent Claim
87 words
a plurality of high strength fiber members extending beTween the blade tip on one side of said filler member to the blade root and therebeyond and then doubling back so as to form a loop and then extending from the blade root to the blade tip on the opposite side of said filler member and being bonded to said filler member on both sides thereof throughout substantially the full span dimension of the filler member, B. means adapted to connect said structural spar to a rotor including:
Claim 58
Dependent Claim
24 words
aligned apertures in said cuff member, and C. a pin member extending through said aligned apertures and through said loop in said fiber members.
Claim 59
Dependent Claim
24 words
aligned apertures in said cuff member, and C. a pin member extending through said aligned apertures and through said loop in said fiber members.
Claim 60
Dependent Claim
12 words
a third means extending through said loop in said fiber members, and
Claim 61
Dependent Claim
12 words
a third means extending through said loop in said fiber members, and
Claim 62
Dependent Claim
12 words
a third means extending through said loop in said fiber members, and
Claim 63
Dependent Claim
12 words
a third means extending through said loop in said fiber members, and
Claim 64
Dependent Claim
12 words
a pin member extending through said loop in said fiber members, and
Claim 65
Dependent Claim
12 words
a pin member extending through said loop in said fiber members, and
Claim 66
Dependent Claim
12 words
a pin member extending through said loop in said fiber members, and
Claim 67
Dependent Claim
12 words
a pin member extending through said loop in said fiber members, and
Claim 68
Dependent Claim
13 words
a third means extending through said loop in said fiber composite members, and
Claim 69
Dependent Claim
13 words
a third means extending through said loop in said fiber composite members, and
Claim 70
Dependent Claim
12 words
a third means extending through said loop in said fiber members, and
Claim 71
Dependent Claim
12 words
a third means extending through said loop in said fiber members, and
Claim 72
Dependent Claim
24 words
aligned apertures in said cuff member, and C. a pin member extending through said aligned apertures and through said loop in said fiber members.
Claim 73
Dependent Claim
24 words
aligned apertures in said cuff member, and C. a pin member extending through said aligned apertures and through said loop in said fiber members.
Claim 74
Dependent Claim
12 words
a pin member extending through said loop in said fiber members, and
Claim 75
Dependent Claim
12 words
a pin member extending through said loop in said fiber members, and
Claim 76
Dependent Claim
12 words
a pin member extending through said loop in said fiber members, and
Claim 77
Dependent Claim
12 words
a pin member extending through said loop in said fiber members, and
Claim 78
Dependent Claim
12 words
a third means extending through said loop in said fiber members, and
Claim 79
Dependent Claim
12 words
a third means extending through said loop in said fiber members, and
Claim 80
Dependent Claim
12 words
a third means extending through said loop in said fiber members, and
Claim 81
Dependent Claim
12 words
a third means extending through said loop in said fiber members, and
Claim 82
Dependent Claim
12 words
a third means extending through said loop in said fiber members, and
Claim 83
Dependent Claim
12 words
a third means extending through said loop in said fiber members, and
Claim 84
Dependent Claim
14 words
A blade according to claim 1 wherein said fiber members are unidirectional glass fibers.
Claim 85
Dependent Claim
12 words
a pin member extending through said loop in said fiber members, and
Claim 86
Dependent Claim
12 words
a pin member extending through said loop in said fiber members, and
Claim 87
Dependent Claim
16 words
means adapted to connect said first and second members and said pin member to the rotor.
Claim 88
Dependent Claim
16 words
means adapted to connect said first and second members and said pin member to the rotor.
Claim 89
Dependent Claim
58 words
A blade according to claim 2 wherein said skin member includes a plurality of layers of fiber members each extending in a direction so as to form an angle with respect to the blade longitudinal axis and having layers forming angles on opposite sides of the blade longitudinal axis so as to form a torque load carrying boot.
Claim 90
Dependent Claim
13 words
means adapted to connect said first, second, and third means to the rotor.
Claim 91
Dependent Claim
13 words
means adapted to connect said first, second, and third means to the rotor.
Claim 92
Dependent Claim
13 words
means adapted to connected said first, second, and third means to the rotor.
Claim 93
Dependent Claim
13 words
means adapted to connected said first, second, and third means to the rotor.
Claim 94
Dependent Claim
13 words
means adapted to connect said first, second, and third means to a rotor.
Claim 95
Dependent Claim
13 words
means adapted to connect said first, second, and third means to a rotor.
Claim 96
Dependent Claim
16 words
means adapted to connect said first and second members and said pin member to the rotor.
Claim 97
Dependent Claim
16 words
means adapted to connect said first and second members and said pin member to the rotor.
Claim 98
Dependent Claim
16 words
means adapted to connect said first and second members and said pin member to the rotor.
Claim 99
Dependent Claim
16 words
means adapted to connect said first and second members and said pin member to the rotor.
Claim 100
Dependent Claim
16 words
means adapted to connect said first and second members and said pin member to the rotor.
Claim 101
Dependent Claim
16 words
means adapted to connect said first and second members and said pin member to the rotor.
Claim 102
Dependent Claim
13 words
means adapted to connect said first, second and third means to the rotor.
Claim 103
Dependent Claim
13 words
means adapted to connect said first, second and third means to the rotor.
Claim 104
Dependent Claim
13 words
means adapted to connect said first, second, and third means to the rotor.
Claim 105
Dependent Claim
13 words
means adapted to connect said first, second, and third means to the rotor.
Claim 106
Dependent Claim
16 words
means adapted to connect said first and second members and said pin member to the rotor.
Claim 107
Dependent Claim
16 words
means adapted to connect said first and second members and said pin member to the rotor.
Claim 108
Dependent Claim
13 words
means adapted to connect said first, second and third means to a rotor.
Claim 109
Dependent Claim
13 words
means adapted to connect said first, second and third means to a rotor.
Claim 110
Dependent Claim
13 words
means adapted to connect said first, second, and third means to a rotor.
Claim 111
Dependent Claim
13 words
means adapted to connect said first, second, and third means to a rotor.
Claim 112
Dependent Claim
18 words
A blade according to claim 4 wherein said torque boot is of substantially circular or oval cross section.
Claim 113
Dependent Claim
42 words
A blade according to claim 1 and including a torque boot made of composite material comprising a plurality of layers of fibrous material extending in different directions and enveloping the blade at the blade root so as to carry blade torsional loads.
Claim 114
Dependent Claim
10 words
A composite helicopter blade having: A. a structural spar including:
Claim 115
Dependent Claim
10 words
A composite helicopter blade having: A. a structural spar including:
Claim 116
Dependent Claim
38 words
A helicopter rotor including: A. a hub mounted for rotation about an axis of rotation, B. a plurality of blades connected to and extending from said hub for rotation therewith to generate lift, each of said blades including:
Claim 117
Dependent Claim
38 words
A helicopter rotor including: A. a hub mounted for rotation about an axis of rotation, B. a plurality of blades connected to and extending from said hub for rotation therewith to generate lift, each of said blades including:
Claim 118
Dependent Claim
48 words
A rotor according to claim 8 and including: A. additional filler material of selected shape and connected to said spar to cooperate therewith in forming the blade cross-sectional shape, and B. a skin member enveloping said spar and said additional filler material to produce a smooth blade surface.
Claim 119
Dependent Claim
58 words
A blade according to claim 8 wherein said skin member includes a plurality of layers of fiber members each extending in a direction so as to form an angle with respect to the blade longitudinal axis and having layers forming angles on opposite sides of the blade longitudinal axis so as to form a torque load carrying boot.
Claim 120
Dependent Claim
18 words
A blade according to claim 10 wherein said torque boot is of substantially circular or oval cross section.
Claim 121
Dependent Claim
43 words
A blade according to claim 8 and including a torque boot is made of composite material comprising a plurality of layers of fibrous material extending in differet directions and enveloping the blade at the blade root so as to carry blade torsional loads.
Claim 122
Dependent Claim
18 words
A composite helicopter blade having a span and a chord and also having: A. a structural spar including:
Claim 123
Dependent Claim
18 words
A composite helicopter blade having a span and a chord and also having: A. a structural spar including:
Claim 124
Dependent Claim
48 words
A blade according to claim 13 and including: A. additional filler material of selected shape and connected to said spar to cooperate therewith in forming the blade cross-sectional shape, and B. a skin member enveloping said spar and said additional filler material to produce a smooth blade surface.
Claim 125
Dependent Claim
10 words
A composite helicopter blade having: A. a structural spar including:
Claim 126
Dependent Claim
10 words
A composite helicopter blade having: A. a structural spar including:
Claim 127
Dependent Claim
10 words
A composite helicopter blade having: A. a structural spar including:
Claim 128
Dependent Claim
10 words
A composite helicopter blade having: A. a structural spar including:
Claim 129
Dependent Claim
10 words
A composite helicopter blade having: A. a structural spar including:
Claim 130
Dependent Claim
10 words
A composite helicopter blade having: A. a structural spar including:
Claim 131
Dependent Claim
38 words
A helicopter rotor including: A. a hub mounted for rotation about an axis of rotation, B. a plurality of blades connected to and extending from said hub for rotation therewith to generate lift, each of said blades including:
Claim 132
Dependent Claim
38 words
A helicopter rotor including: A. a hub mounted for rotation about an axis of rotation, B. a plurality of blades connected to and extending from said hub for rotation therewith to generate lift, each of said blades including:
Claim 133
Dependent Claim
18 words
A composite helicopter blade having a span and a chord and also having: A. a structural spar including:
Claim 134
Dependent Claim
18 words
A composite helicopter blade having a span and a chord and also having: A. a structural spar including:
Claim 135
Dependent Claim
10 words
A composite helicopter blade having: A. a structural spar including:
Claim 136
Dependent Claim
10 words
A composite helicopter blade having: A. a structural spar including:
Claim 137
Dependent Claim
10 words
A composite helicopter blade having: A. a structural spar including:
Claim 138
Dependent Claim
10 words
A composite helicopter blade having: A. a structural spar including:
Claim 139
Dependent Claim
10 words
A composite helicopter blade having: A. a structural spar including:
Claim 140
Dependent Claim
10 words
A composite helicopter blade having: A. a structural spar including:
Claim 141
Dependent Claim
10 words
A composite helicopter blade having: A. a structural spar including:
Claim 142
Dependent Claim
10 words
A composite helicopter blade having: A. a structural spar including:
Claim 143
Dependent Claim
10 words
A composite helicopter blade having: A. a structural spar including:
Claim 144
Dependent Claim
10 words
A composite helicopter blade having: A. a structural spar including:
Claim 145
Dependent Claim
45 words
A blade according to claim 24 wherein said fiber composite members of said skin member and said spar are fabricated in separate layers and wherein the layers of the spar fiber composite members are interleaved with the layers of the skin member fiber composite members.
Claim 146
Dependent Claim
10 words
A composite helicopter blade having: A. a structural spar including:
Claim 147
Dependent Claim
10 words
A composite helicopter blade having: A. a structural spar including:
Claim 148
Dependent Claim
35 words
A blade according to claim 26 wherein said members of said structural spar and said blade skin are fabricated of fiber composite, bonded metal wire or bonded plastic or metal sheets, or a combination thereof.
Claim 149
Dependent Claim
40 words
A blade according to claim 27 wherein said members of said spar and said skin member are fabricated to be a plurality of separate layers and with the layers of the spar interleaved with the layers of the skin member.
Claim 150
Dependent Claim
10 words
A composite helicopter blade having: A. a structual spar including:
Claim 151
Dependent Claim
10 words
A composite helicopter blade having: A. a structual spar including:
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-08-27 | 1977-02-26 | 1977-08-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-08-27 | 1981-02-26 | 1981-08-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-08-27 | 1985-02-26 | 1985-08-28 | $7700.00 | Window Closed / Lapsed |