초록 ▼

A helicopter rotor blade includes a structural composite skin defining a cavity therein; a composite spar disposed within the cavity and adhesively bonded to the skin, a portion of the spar exhibiting a C-shape in cross section; and a foam core disposed within the cavity and adhesively bonded to the

A helicopter rotor blade includes a structural composite skin defining a cavity therein; a composite spar disposed within the cavity and adhesively bonded to the skin, a portion of the spar exhibiting a C-shape in cross section; and a foam core disposed within the cavity and adhesively bonded to the skin. The structural composite skin forms an external, closed box structure configured to transmit mechanical loads encountered by the rotor blade.

대표청구항 ▼

1. A helicopter rotor blade, comprising: a structural composite skin defining a cavity therein;a composite spar disposed within the cavity and adhesively bonded to the skin, a portion of the spar exhibiting a C-shape in cross section; anda foam core disposed within the cavity and adhesively bonded t

1. A helicopter rotor blade, comprising: a structural composite skin defining a cavity therein;a composite spar disposed within the cavity and adhesively bonded to the skin, a portion of the spar exhibiting a C-shape in cross section; anda foam core disposed within the cavity and adhesively bonded to the skin;a composite tube disposed within the cavity and formed from a plurality of plies urged against and adhesively bonded to the composite spar, the foam core, and the skin, so as to provide a compaction pressure internal to the blade during curing of the blade, the composite tube and extending between the composite spar and the foam core, the composite tube being formed from the expansion of a mandrel;wherein the structural composite skin forms an external, closed box structure configured to transmit mechanical loads encountered by the rotor blade; andwherein the structural composite skin is configured for providing significant stiffness and mechanical strength to the rotor blade. 2. The helicopter rotor blade, according to claim 1, wherein at least a portion of the spar is fabricated using an automated fiber placement process. 3. The helicopter rotor blade, according to claim 1, wherein the skin comprises: an upper skin and a lower skin. 4. The helicopter rotor blade, according to claim 1, wherein the spar comprises: an upper portion and a lower portion. 5. The helicopter rotor blade, according to claim 1, wherein the foam core comprises: a closed-cell foam material. 6. The helicopter rotor blade, according to claim 1, having a root and a longitudinal axis, the root defining openings that are generally aligned with the longitudinal axis for connecting the helicopter rotor blade to a helicopter rotor. 7. The helicopter rotor blade, according to claim 1, wherein the structural composite skin comprises a structural, fiber-reinforced, composite material, such as a carbon-reinforced epoxy material. 8. A method for making a helicopter rotor blade, comprising: providing a closed mold having an internal surface defining an outer surface of the helicopter rotor blade;providing a foam core;providing a cured composite upper skin;providing a cured composite lower skin;laying up an uncured upper portion of a spar onto an inner surface of the upper skin;laying up an uncured lower portion of the spar onto an inner surface of the lower skin;providing an elastomeric bladder and a mandrel disposed within the bladder;laying up a plurality of uncured composite plies about the elastomeric bladder;assembling the upper skin, the lower skin, the uncured upper portion of the spar, the uncured lower portion of the spar, the elastomeric bladder with the mandrel disposed therein and the plurality of uncured composite plies laid up on the elastomeric bladder, the foam core, and adhesive into the closed mold; andheating the assembled upper skin, the lower skin, the uncured upper portion of the spar, the uncured lower portion of the spar, the elastomeric bladder with the mandrel disposed therein and the plurality of uncured composite plies laid up on the elastomeric bladder, the foam core, and adhesive;inflating the elastomeric bladder during heating to provide compaction pressure internal to the blade, thereby causing a tight fit between the plurality of uncured composite plies, the uncured upper portion of the spar, the uncured lower portion of the spar, the cured upper skin, the cured lower skin, and the core; andcuring the plurality of uncured composite plies, the uncured upper portion of the spar, and the uncured lower portion of the spar. 9. The method, according to claim 8, wherein laying up the upper portion of the spar onto the inner surface of the upper skin is accomplished, at least in part, by an automated fiber placement process. 10. The method, according to claim 9, wherein laying up the upper portion of the spar onto the inner surface of the upper skin is accomplished by laying up part of the upper portion of the spar onto the inner surface of the upper skin using a manual method. 11. The method, according to claim 8, wherein laying up the lower portion of the spar onto the inner surface of the lower skin is accomplished, at least in part, by an automated fiber placement process. 12. The method, according to claim 11, wherein laying up the lower portion of the spar onto the inner surface of the lower skin is accomplished by laying up part of the lower portion of the spar onto the inner surface of the lower skin using a manual method. 13. The method, according to claim 8, further comprising: generating openings in a root of the helicopter rotor blade generally aligned along a longitudinal axis of the helicopter rotor blade for attaching the helicopter rotor blade to a helicopter rotor.