Unshrouded blading for high bypass turbofan engines

Claim 2

A metal alloy fan blade for a gas turbine engine, the metal alloy fan blade comprising: a blade root; a blade tip oppositely disposed from the blade root; and a reinforcing material bonded to a surface of the metal alloy fan blade at the blade root so as to be remote from the blade tip, the reinforcing material being lo provided in a quantity and thickness so as to sufficiently stiffen the metal alloy fan blade and thereby provide frequency and stability control to the fan blade; whereby the reinforcing material sufficiently stiffens the metal alloy fan blade so as to make unnecessary the use of a part span shroud.

Claim 3

A metal alloy fan blade as recited in claim 1 wherein the reinforcing material is a metal matrix composite material.

Claim 4

A metal alloy fan blade as recited in claim 1 wherein the reinforcing material is a titanium-silicon carbide metal matrix composite material.

Claim 5

A metal alloy fan blade as recited in claim 1 wherein the reinforcing material is excluded from regions of the fan blade which are required to be resistant to foreign object damage.

Claim 6

A metal alloy fan blade as recited in claim 1 wherein the reinforcing material is limited to the lower third of the metal alloy fan blade adjacent to the blade root.

Claim 7

A metal alloy fan blade as recited in claim 1 wherein the thickness of the reinforcing material is about 10 to about 25 percent of the thickness of the metal alloy fan blade.

Claim 8

A metal alloy fan blade as recited in claim 1 wherein the metal alloy fan blade is formed from a titanium alloy.

Claim 9

A metal alloy fan blade as recited in claim 1 wherein the metal alloy fan blade is hollow.

Claim 10

A metal alloy fan blade as recited in claim 1 wherein the reinforcing material is diffusion bonded to the metal alloy fan blade.

Claim 11

A fan blade for a gas turbine engine, the fan blade comprising: a fan blade member having a blade root for securing the fan blade to a hub member and a blade tip oppositely disposed from the blade root, the fan blade member being formed from a titanium alloy; and a metal matrix composite material bonded to a surface of the fan blade member at the blade root so as to be remote from the blade tip, the metal matrix composite material being provided in a quantity and thickness so as to sufficiently stiffen the fan blade and thereby provide frequency and stability control to the fan blade; whereby the metal matrix composite material sufficiently stiffens the fan blade so as to increase the fan blade's flexural frequency, thereby making unnecessary the use of a part span shroud.

Claim 12

A fan blade for a gas turbine engine, the fan blade comprising: a fan blade member having a blade root for securing the fan blade to a hub member and a blade tip oppositely disposed from the blade root, the fan blade member being formed from a titanium alloy; and a metal matrix composite material bonded to a surface of the fan blade member at the blade root so as to be remote from the blade tip, the metal matrix composite material being provided in a quantity and thickness so as to sufficiently stiffen the fan blade and thereby provide frequency and stability control to the fan blade; whereby the metal matrix composite material sufficiently stiffens the fan blade so as to increase the fan blade's flexural frequency, thereby making unnecessary the use of a part span shroud.

Claim 13

A fan blade as recited in claim 10 wherein the metal matrix composite material is a titanium-silicon carbide metal matrix composite material.

Claim 14

A fan blade as recited in claim 10 wherein the metal matrix composite is excluded from regions of the fan blade which are required to be resistant to foreign object damage.

Claim 15

A fan blade assembly for a gas turbine engine, the fan blade assembly comprising: a hub member; a plurality of metal alloy fan blades secured to the hub member, each of the plurality of metal alloy fan blades having a blade root for securing each fan blade to the hub member and a blade tip oppositely disposed from the blade root; and a metal matrix composite material bonded to a surface of each fan blade at its corresponding blade root so as to be remote from its corresponding blade tip, the metal matrix composite material being provided in a quantity and thickness so as to sufficiently stiffen each fan blade and thereby provide frequency and stability control to each fan blade; whereby the metal matrix composite material sufficiently stiffens each fan blade so as to make unnecessary the use of a part span shroud.

Claim 16

A fan blade assembly for a gas turbine engine, the fan blade assembly comprising: a hub member; a plurality of metal alloy fan blades secured to the hub member, each of the plurality of metal alloy fan blades having a blade root for securing each fan blade to the hub member and a blade tip oppositely disposed from the blade root; and a metal matrix composite material bonded to a surface of each fan blade at its corresponding blade root so as to be remote from its corresponding blade tip, the metal matrix composite material being provided in a quantity and thickness so as to sufficiently stiffen each fan blade and thereby provide frequency and stability control to each fan blade; whereby the metal matrix composite material sufficiently stiffens each fan blade so as to make unnecessary the use of a part span shroud.

Claim 17

A fan blade assembly as recited in claim 13 wherein each fan blade is formed from a titanium alloy.

Claim 18

A fan blade assembly as recited in claim 13 wherein the metal matrix composite material is a titanium-silicon carbide metal matrix composite.

Claim 19

A fan blade assembly as recited in claim 13 wherein the metal matrix composite material is excluded from regions of each fan blade which are required to be resistant to foreign object damage.

Claim 20

A fan blade assembly as recited in claim 13 wherein the metal matrix composite material is diffusion bonded to the fan blades.

Claim 21

A fan blade assembly as recited in claim 13 wherein the metal matrix composite material is metallurgically compatible with titanium.

Claim 22

A fan blade assembly as recited in claim 13 wherein the fan blade assembly comprises at least twenty six of the fan blades.