A gas turbine engine 10 is provided in a fan root to tip pressure ratio, defined as the ratio of the mean total pressure of the flow at the fan exit that subsequently flows through the engine core (P.sub.102) to the mean total pressure of the flow at the fan exit that subsequently flows through the bypass duct (P.sub.104), is no greater than a certain value. The gas turbine engine 10 may provide improved efficiency when compared with conventional engines, whilst retaining an acceptable flutter margin.

A thrust reverser assembly for a gas turbine engine including a core engine, a nacelle surrounding at least a portion of the core engine defining a bypass duct between the nacelle and the core engine where an outer door movable between a stowed position and a deployed position extends outwards from the nacelle and a blocker door movable between a stowed position and a deployed position extends into an airflow conduit defined by the bypass duct to deflect air outwards.

A gas turbine engine according to an exemplary aspect of the present disclosure includes, among other things, a turbine section including a fan drive turbine, a geared architecture driven by the fan drive turbine, and a fan driven by the fan drive turbine via the geared architecture. At least one stage of the turbine section includes an array of rotatable blades and an array of vanes. A ratio of the number of vanes to the number blades is greater than or equal to about 1.55. A mechanical tip rotational Mach number of the blades is configured to be greater than or equal to about 0.5 at an approach speed.

A turbofan gas turbine engine includes a core engine within a core nacelle, a fan nacelle at least partially surrounding the core nacelle to define a bypass flow path and a variable fan nozzle exit area for bypass flow, and a pylon variable area flow system which operates to effect the bypass flow. A method of operating a turbofan gas turbine engine is also disclosed.

A gas turbine engine turbine has a high pressure turbine configured to rotate with a high pressure compressor as a high pressure spool in a first direction about a central axis and a low pressure turbine configured to rotate with a low pressure compressor as a low pressure spool in the first direction about the central axis. A power density is greater than or equal to about 1.5 and less than or equal to about 5.5 lbf/cubic inches. A fan is connected to the low pressure spool via a speed changing mechanism and rotates in the first direction.

A gas turbine engine includes a gear assembly, a bypass flow passage, a fan located upstream of the bypass flow passage, a first shaft and a second shaft, a first turbine coupled through the gear assembly to the fan, a first compressor coupled with the first shaft, and a second turbine coupled with the second shaft. The fan includes a hub and a row of fan blades that extend from the hub. The row includes a number (N) of the fan blades that is from 16 to 20, a solidity value (R) at tips of the fan blades, and a ratio of N/R that is from 12.3 to 20.

A gas turbine engine 10 is provided in which a fan having fan blades in which the camber distribution along the span allows the gas turbine engine to operate with improved efficiency when compared with conventional engines, whilst retaining an acceptable flutter margin.

The fan case can be used around a rotary fan of a turbofan engine, the rotary fan including a plurality of circumferentially interspaced blades protruding radially from a rotor, the fan blade case including a first annular wall providing a radially outward delimitation to a gas path around the blades, the first wall being configured to allow blade penetration therethrough while absorbing at least 30% of the kinetic energy in the event of detachment of one of said blades, and a second annular wall surrounding the first annular wall, the second annular wall configured to cooperate with the first annular wall for containing the detachment of the fan blade.

A turbofan engine including: a turbine shaft; a fan shaft; and a reduction mechanism coupling the turbine shaft and the fan shaft, is provided. The turbofan engine has a bypass ratio greater than or equal to 10, and the turbine shaft is supported by four bearings such that the flexural deformation modes of the turbine shaft are positioned in transient phase or outside the operating range of the turbofan engine.

A thrust reverser pivot door may comprise a support structure configured to pivot between a stowed position and a deployed position, and a pivot door outer skin coupled to the support structure, wherein a forward lip of the pivot door outer skin is configured to extend forward of a torque box and overlap the fan case to advantageously increase the overall size or area of the pivot door.