United Technologies Corporation

John M Graff

Leon Stoltze

Blair A Smith

John A Violette

Harry A Nutter, Jr

An electroformed sheath is disclosed for protecting composite components of a part, such as a fan blade of a modern gas turbine engine. The electroformed sheath includes a sheath body having a leading edge; a pressure side and an opposed suction side of the body that meet at the leading edge and extend away from the leading edge to define a sheath cavity therebetween; a head section of the body between the leading edge and the sheath cavity; and an electrically conductive mandrel insert positioned between the pressure and suction sides of the body. In manufacture of the electroformed sheath, the mandrel insert is secured in an appropriate mandrel having an exterior surface approximating the blade's airfoil configuration. The leading edge, head section and pressure and suction sides are electroplated around the mandrel insert so that the insert remains in the sheath body after removal of the mandrel. The position occupied by the mandrel defines the sheath cavity, and the component parts of the blade are secured within the cavity. The mandrel insert enhances electroformation of material from the electroplate bath around the mandrel insert so that the resulting electroformed sheath has a thickness range ratio (being a ratio of the thickness of a thickest part of the sheath (e.g., its leading edge) to the thickness of a thinnest part of the sheath (e.g., trailing edges of the pressure or suction sides)) in excess of 30:1.

Electroformed sheath

A sheath for covering and protecting a component leading edge of an airfoiled component is disclosed. The sheath includes a sheath leading edge, and a first protective side and a second protective side, wherein the first and second protective sides are merged at the sheath leading edge. A cavity is formed between the first and second protective sides, wherein the cavity is adapted to have the airfoiled component positioned therein and engage an inside surface of each of the first and second protective sides. The sheath is formed from a material including cobalt, and preferably a nickel-cobalt composition. Preferred embodiments include cobalt in the nickel-cobalt composition present between 8-32 wt. % and 30-54 wt. %, based on the weight of the sheath. An airfoiled component construction is also disclosed. This construction includes a main structural component formed in the shape of an airfoil, wherein the main structural component has a leading edge, and a sheath covering and protecting the leading edge, wherein the sheath is formed from a material including cobalt such as a nickel-cobalt composition. Preferred embodiments include cobalt in the nickel-cobalt composition present between 8-32 wt. % and 30-54 wt. %, based on the weight of the sheath.

Electroformed sheath and airfoiled component construction

In an apparatus and method for resin transfer molding, a mold including at least two cooperating mold sections is placed in a vacuum chamber. A reinforcing material is positioned between the mold sections, which are separated from one another during evacuation of the chamber, thus maintaining the reinforcing material in a substantially uncompressed condition, to ensure that all gasses and/or liquids are evacuated from the reinforcing material and the mold prior to resin injection. After evacuation, the mold sections are brought almost into engagement to substantially define a mold cavity, and resin is injected into the mold cavity. Prior to terminating the resin injection, the mold sections are brought into engagement, and final resin injection is performed. The injected resin is then cured in accordance with the particular type of resin injected.

Apparatus for resin transfer molding

A method of manufacturing a lightweight composite propulsor blade of spar and shell construction comprises forming a composite spar (30) having an elongated foam body (20) bonded to a short metal retention tulip (10) and overlayed with a dry braided wrap of angular structural fibers and substantially unidirectional spanwisely aligned structural fiber plies disposed between the braided layers; adding a leading edge foam body (42) and a trailing edge foam body (44) to the spar assembly to form a blade subassembly (50); providing a dry braided fabric wrap over the blade assembly; disposing the fabric covered blade subassembly into a shell molding die and simultaneously impregnating the dry spar fabric wrap and the dry shell fabric wrap with a curable resin material; and curing the impregnated blade subassembly.

Composite blade manufacture

Bonding pressure is uniformly applied to the lay-up (70) of a bonded product (10) by the disposition of flexible, compressible, perforated sheet material (85) within the lay-up during the manufacture of the product by diffusion bonding.

Manufacture of bonded structures

Bonding pressure is uniformly applied to the lay-up (70) of a bonded product (10) by the disposition of flexible, compressible, perforated sheet material (85) between the lay-up and a pair of molds (75 and 80) during the manufacture of the product by diffusion bonding.

Fabrication of bonded structures

A partially compacted fiber-reinforced metallic tape has a layer of collimated fibers between two layers of metal foil, the foil being partially compacted around the fibers, somewhat deforming the foil around the fibers and, in selected areas only, the foil being fully compacted around the fibers forming complete bonds between the metal foil layers and the fibers in these areas.

Growing community of inventors

West Suffield, CT, United States of America

John M Graff