A gas turbine engine comprising: a combustor configured to initiate combustion; and a turbine comprising a stator vane ring defining a plurality of passageways between adjacent vanes; wherein at least one of the passageways is provided with a restrictor which defines a temporary gas washed surface for the stator vane ring and is configured to be ablated upon initiation of combustion to reveal an operational gas washed surface of the stator vane ring. A method of starting a gas turbine engine is also described.

A rotor blade of a gas turbine engine includes a pressure side, and a suction side opposite the pressure side and defining a rotor blade profile therebetween, the pressure side and the suction side each extending from a blade root to a blade tip. The rotor blade defines a cross-sectional median line midway between the pressure side and the suction side. The cross-sectional median line extends in a generally radial direction from the blade root to a lean point between the blade root and the blade tip. The cross-sectional median line extends off of radial from the lean point to the blade tip, defining a lean of the rotor blade between the lean point and the blade tip.

Airfoil assemblies for gas turbine engines are provided. For example, an airfoil assembly comprises an airfoil, an inner band defining an inner opening shaped complementary to an inner end of the airfoil, and an outer band defining an outer opening shaped complementary to an outer end of the airfoil. The airfoil inner end is received with the inner opening, and the airfoil outer end is received within the outer opening. A strut extends radially through an airfoil cavity. A first pad is defined at a first radial location within the cavity. A second pad is defined within the cavity at a second, different radial location. In some embodiments, the airfoil assembly inner band includes a first inner flange, through which the inner band is secured to a support structure, and the outer band includes a first outer flange, through which the outer band is secured to a support structure.

A compressor vane is provided. The compressor vane may include a first surface directed toward air introduced into a compressor, a second surface directed in a direction opposite to the first surface, and two tangent lines in which the first and second surfaces meet, wherein a rate of change, with respect to a height of the compressor vane, of a maximum separation distance, between the first surface and the second surface, divided by a distance from one to the other of the two tangent lines in a cross-section at one position of the height of the compressor vane in a direction starting from a portion of the compressor vane closest to a center tie rod and toward a compressor housing varies with the height of the compressor vane away from the portion of the compressor vane closest to the center tie rod.

A gas turbine engine comprises a fan mounted to rotate about a main longitudinal axis; an engine core, comprising in axial flow series a compressor, a combustor, and a turbine coupled to the compressor through a shaft; a reduction gearbox that receives an input from the shaft and outputs drive to the fan so as to drive the fan at a lower rotational speed than the shaft; wherein the compressor comprises a first stage at an inlet and a second stage, downstream of the first stage, comprising respectively a first rotor with a row of first blades and a second rotor with a row of second blades, the first and second blades comprising respective leading edges, trailing edges and tips, and wherein the ratio of a maximum leading edge radius of the first blades to a maximum leading edge radius of the second blades is greater than 2.8.

A turbine engine includes a first compression section includes a last blade trailing edge radial tip length that is greater than about 67% of the radial tip length of a leading edge of a first stage of the first compression section. A second compression section includes a last blade trailing edge radial tip length that is greater than about 57% of a radial tip length of a leading edge of a first stage of the first compression section.

In an axial compressor including a row of rotor blades (70) provided on a rotational shaft (20) around a central axial line of the rotational shaft at a prescribed pitch, and a row of stator vanes (40) provided on a casing around the central axial line at a prescribed pitch so as to adjoin the row of rotor blades on an upstream or downstream side thereof, the rotor blades each extend along a radial line (R) emanating from the central axial line, and the stator vanes each extend along a slanted line (I) that is slanted with respect to a corresponding radial line in a circumferential direction.

A turbofan engine includes a fan section including a fan blade having a leading edge and hub to tip ratio of less than about 0.34 and greater than about 0.020 measured at the leading edge and a speed change mechanism with gear ratio greater than about 2.6 to 1. A first compression section includes a last blade trailing edge radial tip length that is greater than about 67% of the radial tip length of a leading edge of a first stage of the first compression section. A second compression section includes a last blade trailing edge radial tip length that is greater than about 57% of a radial tip length of a leading edge of a first stage of the first compression section.

A compressor includes impellers each having its chord angle less than its stall angle. The impellers can be used in a contra-rotating impeller arrangement without static diffusers. The contra-rotating impeller arrangement provides for much larger nominal flow rates than conventional single rotating impeller arrangements with the same chord angles. Accordingly, a surge free design is provided without excessively compromising the nominal flow rate. Techniques for enhancing stall characteristics of the impellers are also described.

A tandem rotor disk apparatus may include a rotor disk body concentric about an axis. The tandem rotor disk apparatus may also include a first blade extending radially outward of the rotor disk body and a second blade extending radially outward of the rotor disk body. The first blade may be offset from the second blade in a direction parallel to the axis. The tandem rotor disk apparatus may be implemented in a gas turbine engine with no intervening stator vane stages disposed between the first blade and the second blade. The tandem rotor disk apparatus may include two separate rotor disk bodies.