Hybrid composite flexbeam for a helicopter bearingless main rotor assembly
First Claim
1. A hybrid composite flexbeam for a bearingless main rotor assembly, comprising:
- a pitch region formed by a plurality of unidirectional fiberglass plies, a plurality of unidirectional fiberglass and graphite plies in interleaved combination, and a plurality of unidirectional graphite plies, said plurality of unidirectional graphite plies defining a cruciform configuration in cross section for said pitch region, and wherein said plurality of unidirectional fiberglass plies, said plurality of unidirectional fiberglass and graphite plies, and said plurality of unidirectional graphite plies extend from root to tip of said hybrid composite flexbeam;
an inboard transition region comprised of unidirectional fiberglass plies in abutting relation with edges of said plurality of unidirectional graphite plies defining said cruciform configuration, said abutting unidirectional fiberglass plies extending inboardly to said root of said hybrid flexbeam;
a second inboard tapered region formed by a plurality of unidirectional fiberglass and graphite plies of varying lengths internally interleaved in combination with said plurality of unidirectional fiberglass plies, said plurality of unidirectional fiberglass and graphite plies, said plurality of unidirectional graphite plies, and said plurality of abutting unidirectional fiberglass plies extending inboardly from said inboard transition region, said plurality of internally interleaved unidirectional fiberglass and graphite plies of varying lengths extending inboardly to said root of said hybrid composite flexbeam;
a first inboard tapered region formed by a plurality of fiberglass and graphite cross plies of varying lengths internally interleaved in combination with said plurality of unidirectional fiberglass plies, said plurality of unidirectional fiberglass and graphite plies, said plurality of unidirectional graphite plies, said plurality of internally interleaved unidirectional fiberglass and graphite plies of varying lengths, and said plurality of abutting unidirectional fiberglass plies extending inboardly from said second inboard tapered region, said plurality of internally interleaved fiberglass and graphite cross plies of varying lengths extending inboardly to said root of said hybrid composite flexbeam;
a hub attachment region formed by said plurality of unidirectional fiberglass plies, said plurality of unidirectional fiberglass and graphite plies, said plurality of unidirectional graphite plies, said plurality of internally interleaved unidirectional fiberglass and graphite plies of varying lengths, said plurality of internally interleaved fiberglass and graphite cross plies of varying lengths, and said plurality of abutting unidirectional fiberglass plies extending inboardly from said first inboard tapered region;
an outboard transition region comprised of unidirectional fiberglass plies in abutting relation with edges of said plurality of unidirectional graphite plies defining said cruciform configuration, said abutting unidirectional fiberglass plies extending outboardly to said tip of said hybrid flexbeam;
an outboard tapered region formed by a plurality of fiberglass and graphite cross plies and a plurality of unidirectional fiberglass plies of varying lengths interleaved in combination with said plurality of unidirectional fiberglass plies, said plurality of unidirectional fiberglass and graphite plies, said plurality of unidirectional graphite plies, and said plurality of abutting unidirectional fiberglass plies extending outboardly from said outboard transition region, said plurality of internally interleaved fiberglass and graphite cross plies and said plurality of internally interleaved unidirectional fiberglass plies of varying lengths extending outboardly to said tip of said hybrid composite flexbeam; and
a torque tube, main rotor blade attachment region formed by said plurality of unidirectional fiberglass plies, said plurality of unidirectional fiberglass and graphite plies, said plurality of unidirectional graphite plies, said plurality of internally interleaved fiberglass and graphite cross plies and said plurality of internally interleaved unidirectional fiberglass plies of varying lengths, and said plurality of abutting unidirectional fiberglass plies extending outboardly from said outboard tapered region.
2 Assignments
0 Petitions
Accused Products
Abstract
A hybrid composite flexbeam for a soft inplane bearingless main rotor assembly has eight spanwise regions: a hub attachment region; a first tapered region; a second tapered region; an inboard transition region; a pitch region having a cruciform configuration; an outboard transition region; a tapered outboard transition region; and a main rotor blade, torque tube attachment region. The pitch region is formed from unidirectional fiberglass plies, a 50/50 admixture of unidirectional fiberglass and graphite plies, and unidirectional graphite plies, all of which extend from root to tip of the hybrid flexbeam. Unidirectional fiberglass and graphite plies of varying lengths are interleaved in the second inboard tapered region. Fiberglass and graphite cross plies of varying lengths are interleaved in the first inboard tapered region. Fiberglass and graphite cross plies and unidirectional fiberglass plies of varying length are interleaved in the outboard tapered region. The ends of the plies of varying length form distributed ply drop-off arrangements in the first and second inboard tapered regions and the outboard tapered regions. The distributed arrangement of ply endings cause kick loads in the hybrid flexbeam to be distributed across the ply buildups. Fiberglass edge caps having a U-shaped configuration may be disposed in combination with the leading and trailing edges of the hybrid flexbeam, starting at the limits of the pitch region and extending inboardly and outboardly therefrom, respectively.
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Citations
24 Claims
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1. A hybrid composite flexbeam for a bearingless main rotor assembly, comprising:
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a pitch region formed by a plurality of unidirectional fiberglass plies, a plurality of unidirectional fiberglass and graphite plies in interleaved combination, and a plurality of unidirectional graphite plies, said plurality of unidirectional graphite plies defining a cruciform configuration in cross section for said pitch region, and wherein said plurality of unidirectional fiberglass plies, said plurality of unidirectional fiberglass and graphite plies, and said plurality of unidirectional graphite plies extend from root to tip of said hybrid composite flexbeam; an inboard transition region comprised of unidirectional fiberglass plies in abutting relation with edges of said plurality of unidirectional graphite plies defining said cruciform configuration, said abutting unidirectional fiberglass plies extending inboardly to said root of said hybrid flexbeam; a second inboard tapered region formed by a plurality of unidirectional fiberglass and graphite plies of varying lengths internally interleaved in combination with said plurality of unidirectional fiberglass plies, said plurality of unidirectional fiberglass and graphite plies, said plurality of unidirectional graphite plies, and said plurality of abutting unidirectional fiberglass plies extending inboardly from said inboard transition region, said plurality of internally interleaved unidirectional fiberglass and graphite plies of varying lengths extending inboardly to said root of said hybrid composite flexbeam; a first inboard tapered region formed by a plurality of fiberglass and graphite cross plies of varying lengths internally interleaved in combination with said plurality of unidirectional fiberglass plies, said plurality of unidirectional fiberglass and graphite plies, said plurality of unidirectional graphite plies, said plurality of internally interleaved unidirectional fiberglass and graphite plies of varying lengths, and said plurality of abutting unidirectional fiberglass plies extending inboardly from said second inboard tapered region, said plurality of internally interleaved fiberglass and graphite cross plies of varying lengths extending inboardly to said root of said hybrid composite flexbeam; a hub attachment region formed by said plurality of unidirectional fiberglass plies, said plurality of unidirectional fiberglass and graphite plies, said plurality of unidirectional graphite plies, said plurality of internally interleaved unidirectional fiberglass and graphite plies of varying lengths, said plurality of internally interleaved fiberglass and graphite cross plies of varying lengths, and said plurality of abutting unidirectional fiberglass plies extending inboardly from said first inboard tapered region; an outboard transition region comprised of unidirectional fiberglass plies in abutting relation with edges of said plurality of unidirectional graphite plies defining said cruciform configuration, said abutting unidirectional fiberglass plies extending outboardly to said tip of said hybrid flexbeam; an outboard tapered region formed by a plurality of fiberglass and graphite cross plies and a plurality of unidirectional fiberglass plies of varying lengths interleaved in combination with said plurality of unidirectional fiberglass plies, said plurality of unidirectional fiberglass and graphite plies, said plurality of unidirectional graphite plies, and said plurality of abutting unidirectional fiberglass plies extending outboardly from said outboard transition region, said plurality of internally interleaved fiberglass and graphite cross plies and said plurality of internally interleaved unidirectional fiberglass plies of varying lengths extending outboardly to said tip of said hybrid composite flexbeam; and a torque tube, main rotor blade attachment region formed by said plurality of unidirectional fiberglass plies, said plurality of unidirectional fiberglass and graphite plies, said plurality of unidirectional graphite plies, said plurality of internally interleaved fiberglass and graphite cross plies and said plurality of internally interleaved unidirectional fiberglass plies of varying lengths, and said plurality of abutting unidirectional fiberglass plies extending outboardly from said outboard tapered region. - View Dependent Claims (22, 23, 24)
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2. A hybrid composite flexbeam for a bearingless main rotor assembly, comprising:
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a pitch region formed by a plurality of unidirectional fiberglass plies, a plurality of unidirectional fiberglass and graphite plies in interleaved combination, and a plurality of unidirectional graphite plies, said plurality of unidirectional graphite plies defining a cruciform configuration in cross section for said pitch region, and wherein said plurality of unidirectional fiberglass plies, said plurality of unidirectional fiberglass and graphite plies, and said plurality of unidirectional graphite plies extend from root to tip of said hybrid composite flexbeam; an inboard transition region comprised of unidirectional fiberglass plies in abutting relation with edges of said plurality of unidirectional graphite plies defining said cruciform configuration, said abutting unidirectional fiberglass plies extending inboardly to said root of said hybrid flexbeam; a second inboard tapered region formed by a plurality of unidirectional fiberglass and graphite plies of varying lengths internally interleaved in combination with said plurality of unidirectional fiberglass plies, said plurality of unidirectional fiberglass and graphite plies, said plurality of unidirectional graphite plies, and said plurality of abutting unidirectional fiberglass plies extending inboardly from said inboard transition region, said plurality of internally interleaved unidirectional fiberglass and graphite plies of varying lengths extending inboardly to said root of said hybrid composite flexbeam; a first inboard tapered region formed by a plurality of fiberglass and graphite cross plies of varying lengths internally interleaved in combination with said plurality of unidirectional fiberglass plies, said plurality of unidirectional fiberglass and graphite plies, said plurality of unidirectional graphite plies, said plurality of internally interleaved unidirectional fiberglass and graphite plies of varying lengths, and said plurality of abutting unidirectional fiberglass plies extending inboardly from said second inboard tapered region, said plurality of internally interleaved fiberglass and graphite cross plies of varying lengths extending inboardly to said root of said hybrid composite flexbeam; a hub attachment region formed by said plurality of unidirectional fiberglass plies, said plurality of unidirectional fiberglass and graphite plies, said plurality of unidirectional graphite plies, said plurality of internally interleaved unidirectional fiberglass and graphite plies of varying lengths, said plurality of internally interleaved fiberglass and graphite cross plies of varying lengths, and said plurality of abutting unidirectional fiberglass plies extending inboardly from said first inboard tapered region; an outboard transition region comprised of unidirectional fiberglass plies in abutting relation with edges of said plurality of unidirectional graphite plies defining said cruciform configuration, said abutting unidirectional fiberglass plies extending outboardly to said tip of said hybrid flexbeam; an outboard tapered region formed by a plurality of fiberglass and graphite cross plies and a plurality of unidirectional fiberglass plies of varying lengths interleaved in combination with said plurality of unidirectional fiberglass plies, said plurality of unidirectional fiberglass and graphite plies, said plurality of unidirectional graphite plies, and said plurality of abutting unidirectional fiberglass plies extending outboardly from said outboard transition region, said plurality of internally interleaved fiberglass and graphite cross plies and said plurality of internally interleaved unidirectional fiberglass plies of varying lengths extending outboardly to said tip of said hybrid composite flexbeam; a torque tube, main rotor blade attachment region formed by said plurality of unidirectional fiberglass plies, said plurality of unidirectional fiberglass and graphite plies, said plurality of unidirectional graphite plies, said plurality of internally interleaved fiberglass and graphite cross plies and said plurality of internally interleaved unidirectional fiberglass plies of varying lengths, and said plurality of abutting unidirectional fiberglass plies extending outboardly from said outboard tapered region; and a plurality of fiberglass edge caps having a U-shaped configuration disposed in combination the leading and trailing edges of said hybrid composite flexbeam, respectively, said plurality of fiberglass edge caps having fiber orientations of ±
45°
, and wherein said plurality of fiberglass edge caps includea first fiberglass edge cap disposed in combination with the leading edge of said hybrid composite flexbeam from the outboard limit of said inboard transition region into said first inboard tapered region, a second fiberglass edge cap disposed in combination with the trailing edge of said hybrid composite flexbeam from the outboard limit of said inboard transition region into said first inboard tapered region, a third fiberglass edge cap disposed in combination with the leading edge of said hybrid composite flexbeam from the inboard limit of said outboard transition region into said outboard tapered region, and a fourth fiberglass edge cap disposed in combination with the trailing edge of said hybrid composite flexbeam from the inboard limit of said outboard transition region into said outboard tapered region.
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3. A hybrid composite flexbeam for a bearingless main rotor assembly, comprising:
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a pitch region formed by a plurality of unidirectional fiberglass plies, a plurality of unidirectional fiberglass and graphite plies in interleaved combination, and a plurality of unidirectional graphite plies, said plurality of unidirectional graphite plies defining a cruciform configuration in cross section for said pitch region, and wherein said plurality of unidirectional fiberglass plies, said plurality of unidirectional fiberglass and graphite plies, and said plurality of unidirectional graphite plies extend from root to tip of said hybrid composite flexbeam; a second inboard tapered region formed by a plurality of unidirectional fiberglass and graphite plies of varying lengths internally interleaved in combination with said plurality of unidirectional fiberglass plies, said plurality of unidirectional fiberglass and graphite plies, and said plurality of unidirectional graphite plies extending inboardly from said pitch region, said plurality of internally interleaved unidirectional fiberglass and graphite plies of varying lengths extending inboardly to said root of said hybrid composite flexbeam; a first inboard tapered region formed by a plurality of fiberglass and graphite cross plies of varying lengths internally interleaved in combination with said plurality of unidirectional fiberglass plies, said plurality of unidirectional fiberglass and graphite plies, said plurality of unidirectional graphite plies, and said plurality of internally interleaved unidirectional fiberglass and graphite plies of varying lengths extending inboardly from said second inboard tapered region, said plurality of internally interleaved fiberglass and graphite cross plies of varying lengths extending inboardly to said root of said hybrid composite flexbeam; a hub attachment region formed by said plurality of unidirectional fiberglass plies, said plurality of unidirectional fiberglass and graphite plies, said plurality of unidirectional graphite plies, aid plurality of internally interleaved unidirectional fiberglass and graphite plies of varying lengths, and said plurality of internally interleaved fiberglass and graphite cross plies of varying lengths extending inboardly from said first inboard tapered region; an outboard tapered region formed by a plurality of fiberglass and graphite cross plies and a plurality of unidirectional fiberglass plies of varying lengths interleaved in combination with said plurality of unidirectional fiberglass plies, said plurality of unidirectional fiberglass and graphite plies, and said plurality of unidirectional graphite plies extending outboardly from said pitch region, said plurality of internally interleaved fiberglass and graphite cross plies and said plurality of internally interleaved unidirectional fiberglass plies of varying lengths extending outboardly to said tip of said hybrid composite flexbeam; and a torque tube, main rotor blade attachment region formed by said plurality of unidirectional fiberglass plies, said plurality of unidirectional fiberglass and graphite plies, said plurality of unidirectional graphite plies, and said plurality of internally interleaved fiberglass and graphite cross plies and said plurality of internally interleaved unidirectional fiberglass plies of varying lengths extending outboardly from said outboard tapered region. - View Dependent Claims (4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21)
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Specification