Aerodynamic rotor blade of composite material fabricated in one cure cycle

A method of fabricating a rotor blade from fiber reinforced resin composite material in a molding tool having complementary portions, the inner surface of said tool in assembled combination having the shape of the outer surface of the rotor blade, an upper tool portion corresponding to the upper surface of the rotor blade, a lower tool portion corresponding to the lower surface of the rotor blade, comprising the steps of:

• fabricating from uncured composite material upper blade components to be located above a plane located substantially midway between the upper and lower surfaces of the blade and lower blade components to be located below said plane, said upper and lower blade components including upper and lower spar packs, respectively;
• forming from structural honeycomb a fairing core having the shape of a portion of an airfoil located behind the spar packs;
• forming a precompacted noseblock and a precompacted trailing edge block of uncured composite material;
• disposing the upper tool portion with its inner surface facing upward;
• placing in the upper tool portion the noseblock, and upper blade components;
• placing a stiffened, pneumatically sealed flexible bag adapted to be pressurized in the upper tool portion over the upper spar pack of the upper blade components;
• placing in the upper tool portion the fairing core, trailing edge block and lower blade components, the lower spar pack of the lower blade components being placed over the bag;
• closing the tool by forcing the lower tool portion against the contents of the upper tool portion to a predetermined position relative to the upper tool portion and sealing the ends of the tool;
• pressurizing the bag;
• and
• heating the tool and its contents in accordance with a temperature cure cycle that polymerizes the resin of the composite material and bonds the members of the blade mutually.

An aerodynamic rotor blade assembly fabricated of fiber-reinforced resin composite material, having outer surfaces in the form of an airfoil having a leading edge, a trailing edge, radial length and depth, comprising:

• a spar member extending chordwise along the upper and lower surfaces of the airfoil from a noseblock engaging portion to a trailing edge portion, including a first spar pack located on a first side of a plane located substantially midway between the upper and lower surfaces of the airfoil and a second spar pack located on a second side of said plane;
• a noseblock located at the leading edge surface of the airfoil, a portion of said spar packs overlapping the noseblock;
• an upper spar wrap member covering the upper surface of the noseblock and the upper spar pack, extending from the airfoil leading edge to a first edge located at the midplane;
• a lower spar wrap member covering the lower surface of the noseblock and the lower spar pack, extending from the airfoil leading edge to a second edge located at the midplane;
• a fairing core having the shape of a portion of an airfoil located behind the spar packs, extending the depth of the airfoil contour;
• a trailing edge block located behind the fairing core, extending radially the length of the airfoil, chordwise from the fairing core to the trailing edge of the airfoil, and the depth of the airfoil;
• an upper fairing skin extending radially the length of the airfoil and chordwise from the leading edge to the trailing edge, covering the outer surface of the upper spar wrap, the upper surface of the fairing core and the trailing edge block;
• and
• a lower fairing skin extending radially the length of the rotor blade and chordwise from the leading edge to the trailing edge, covering the outer surface of the lower spar wrap, the lower surface of the fairing core and the trailing edge block.