Abstract: A thin film that forms an interface between metal surfaces and polymeric inserts of aircraft engine fan blades. The thin film is formed from a chemical comprised of carbon black, at least one evaporable solvent, a combination of phenolic-like resins dissolved in the solvent and the balance filler and inert ingredients. The thin film, upon drying of the evaporable solvent, forms a phenolic that bonds with the metallic portion of the fan blade. After the polymeric material is applied to recesses in the fan blade and cured, a chemical bond is formed between the thin film and the elastomeric inserts. The bonded structure has improved FWT peak stresses and improved fracture toughness.

Abstract: A formulation used in the construction of lightweight aircraft engine fan blades. The formulation comprises a polyurethane elastomer composition, which is formed from a prepolymer, a curative and an antioxidant and molded into the blades. Optionally, a hindered amine light stabilizer and/or an ultraviolet absorber may be added to the formulation. The aircraft engine fan blade is formed from a metal, such as titanium alloy. Pockets are machined into the fan blade, so as to lessen the amount of metal used to construct the blade, thereby lowering the total weight of the blade. The formulation of the present invention is positioned in the pockets of the fan blade, so as to maintain the structural integrity of the blade against bird strikes and the like, while at the same time providing a fan blade which is significantly lighter than all-metal fan blades.

Abstract: A hybrid gas turbine engine airfoil is made by forming a metal airfoil with a pocket in one side thereof. The pocket is covered by a caul. An elastomeric fluid is injected into the pocket and cured therein for bonding thereto. The caul is removed from the airfoil to expose the cured elastomer conforming to the aerodynamic profile thereof.