Fan

1. A fan for a gas turbine engine, the fan comprising:

a first set of fan blades and a second set of fan blades arranged circumferentially around a hub,

each of the fan blades of the first and second set comprises an organic matrix composite body and a leading edge member connected to the body,

wherein the leading edge member of the first set of fan blades has a mass less than the leading edge member of the second set of fan blades,

wherein a leading edge region of the first set of fan blades and a leading edge region of the second set of fan blades have a same exterior shape,

wherein the mass of a radially inner portion of the leading edge member of the blades of the first set of blades is less than the mass of a radially inner portion of the leading edge member of the blades of the second set of blades, wherein the radially inner portion extends from a mid-spanwise location to a root of the blade, and

wherein the mass of the leading edge member of the second set of fan blades is increased by providing a leading edge member with a greater volume in the region of greater mass than the fan blades of the first set.

2. The fan according to claim 1 , wherein the blades of the first set and of the second set have the same gas washed surface area, shape and profile.

3. The fan according to claim 1 , wherein the volume of the leading edge member of the first set of fan blades is smaller than the volume of the leading edge member of the second set of fan blades.

4. The fan according to claim 1 , wherein the mass of a radially outer portion of the leading edge member of the first set is the same as the mass of a radially outer portion of the leading edge member of the second set, the radially outer portion of the leading edge member extends from a mid-spanwise location of the blade to a tip of the blade.

5. The fan according to claim 1 , wherein the mass of a root portion of the leading edge member of the first set is less than the mass of a root portion of the leading edge member of the blades of the second set, the root portion extending from a spanwise location that is 30% of the total span of the blade to a root of the blade.

6. The fan according to claim 1 , wherein the leading edge member of the first set and the second set comprises a forward portion that defines a leading edge of the blade, a wing that extends from the forward portion along a suction side of the blade and a wing that extends from the forward portion along a pressure side of the blade, and wherein the forward portion of the first set of blades has a lower mass or volume than the forward portion of the second set of blades.

7. The fan according to claim 1 , wherein the leading edge member of the first set and the second set comprises a forward portion that defines a leading edge of the blade, a wing that extends from the forward portion along a suction side of the blade and a wing that extends from the forward portion along a pressure side of the blade, and wherein the wings of the first set of blades have a lower mass or volume than the wings of the second set of blades.

8. The fan according to claim 1 , wherein the leading edge member is made from a metallic material.

9. The fan according to claim 8 , wherein the leading edge member is made from steel, titanium or a titanium alloy.

10. The fan according to claim 1 , wherein the body is made from a carbon reinforced resin matrix material.

11. The fan according to claim 1 , wherein the blades of the first set and of the second set have the same gas washed surface area, shape and profile and wherein the volume of the leading edge member of the first set of fan blades is smaller than the volume of the leading edge member of the second set of fan blades.

12. A gas turbine engine comprising the fan according to claim 1 .