Abstract: A rotor for a gas turbine engine includes a hub having an outer periphery, a first plurality of blades arranged on the outer periphery of the hub, and a second plurality of blades arranged on the outer periphery of the hub. The first plurality of blades is made of a first material and has a first elastic modulus over density ratio. The first plurality of blades has a first natural frequency. The second plurality of blades is made of a second material and has a second elastic modulus over density ratio. The second elastic modulus over density ratio is different from the first elastic modulus over density ratio. The second plurality of blades has a second natural frequency different from the first natural frequency. A method of fabricating a bladed rotor is also presented.

Abstract: A gas turbine having an annular casing with a series of circumferentially spaced openings defined therethrough; a plurality of vanes extending radially inwardly though respective casing openings, an outer end of the vanes projecting radially outwardly from the casing through the respective openings and located within the respective openings by grommets, and an inner end of the vanes being mounted to an inner portion of the casing; a flexible, segmented strap extending around the annular casing, surrounding the projecting outer ends of the vanes; and a spring radially loading the flexible strap configured to apply a tension force to the flexible strap.

Abstract: A rotor for a gas turbine engine includes a hub having an outer periphery, a first plurality of blades arranged on the outer periphery of the hub, and a second plurality of blades arranged on the outer periphery of the hub. The first plurality of blades is made of a first material and has a first elastic modulus over density ratio. The first plurality of blades has a first natural frequency. The second plurality of blades is made of a second material and has a second elastic modulus over density ratio. The second elastic modulus over density ratio is different from the first elastic modulus over density ratio. The second plurality of blades has a second natural frequency different from the first natural frequency. A method of fabricating a bladed rotor is also presented.

Abstract: A gas turbine engine has a spool including compressor and turbine rotors connected by a first shaft. The first shaft extends concentrically around a second shaft. The first shaft forward end has a portion with an inner diameter of close tolerance with the second shaft. The second shaft has a region of enlarged diameter located axially aft of the compressor rotor but axially forward of the forward end of the first shaft. The region of enlarged diameter has a diameter greater than the inner diameter of the forward end portion of the first shaft to cause the region of enlarged diameter of the second shaft to engage the first shaft in interference in the event that the second shaft is moved axially aft relative to the first shaft more than a pre-selected axial distance.

Abstract: A gas turbine having an annular casing with a series of circumferentially spaced openings defined therethrough; a plurality of vanes extending radially inwardly though respective casing openings, an outer end of the vanes projecting radially outwardly from the casing through the respective openings and located within the respective openings by grommets, and an inner end of the vanes being mounted to an inner portion of the casing; a flexible, segmented strap extending around the annular casing, surrounding the projecting outer ends of the vanes; and a spring radially loading the flexible strap configured to apply a tension force to the flexible strap.

Abstract: A gas turbine engine has a rear mounting assembly incorporating a mounting apparatus attached to a bypass duct wall with a link device for transferring core portion related inertia-induced loads, from an MTF of the core portion in a short circuit across an annular bypass air passage to the bypass duct wall.

Abstract: A gas turbine engine has a spool including compressor and turbine rotors connected by a first shaft. The first shaft extends concentrically around a second shaft. The first shaft forward end has a portion with an inner diameter of close tolerance with the second shaft. The second shaft has a region of enlarged diameter located axially aft of the compressor rotor but axially forward of the forward end of the first shaft. The region of enlarged diameter has a diameter greater than the inner diameter of the forward end portion of the first shaft to cause the region of enlarged diameter of the second shaft to engage the first shaft in interference in the event that the second shaft is moved axially aft relative to the first shaft more than a pre-selected axial distance.

Abstract: An internal heating arrangement for a centrifugal impeller for a gas turbine engine is provided having at least one heating passage extending through into the rotor for directing air bled from the rotor exit along the backface and forwardly through the impeller.

Abstract: A method of operating a gas turbine engine having a rotatable turbine shaft with an electric machine mounted to the shaft. The method includes providing supplemental acceleration and/or deceleration of the turbine shaft of the gas turbine engine through the use of the electric machine operated as an electric motor and/or an electric generator, in order to avoid an undesirable engine speed range during engine operation.

Abstract: A gas turbine engine has a rear mounting assembly incorporating a mounting apparatus attached to a bypass duct wall with a link device for transferring core portion related inertia-induced loads, from an MTF of the core portion in a short circuit across an annular bypass air passage to the bypass duct wall.

Abstract: An internal heating arrangement for a centrifugal impeller for a gas turbine engine is provided having at least one heating passage extending through into the rotor for directing air bled from the rotor exit along the backface and forwardly through the impeller.

Abstract: A vane assembly for a gas turbine engine including a shroud with openings defined about a circumference of the shroud and vanes extending radially from the shroud with a vane tip in each opening. Isolating apparatus are disposed in each opening to isolate the vane tip from the shroud ring. Each vane tip is engaged with the shroud by retaining apparatus for restricting movement of the vane tip in an axial direction relative to the shroud.

Abstract: A method of operating a gas turbine engine having a rotatable turbine shaft with an electric machine mounted to the shaft. The method includes providing supplemental acceleration and/or deceleration of the turbine shaft of the gas turbine engine through the use of the electric machine operated as an electric motor and/or an electric generator, in order to avoid an undesirable engine speed range during engine operation.

Abstract: A vane assembly for a gas turbine engine including a shroud with openings defined therein about a circumference thereof and vanes extending radially from the shroud with a vane tip in each opening. Isolating means are disposed in each opening to isolate the vane tip from the shroud ring. Each vane tip is engaged with the shroud by retaining means for restricting movement of the vane tip in an axial direction relative to said shroud.