A gas turbine engine defining a centerline and a circumferential direction, the gas turbine engine including: a turbomachine comprising a compressor section, a combustion section, and a turbine section arranged in serial flow order, the turbomachine defining a working gas flowpath and a fan duct flowpath; a primary fan driven by the turbomachine defining a primary fan tip radius R.sub.1 and a primary fan hub radius R.sub.2; a secondary fan located downstream of the primary fan and driven by the turbomachine, at least a portion of an airflow from the primary fan configured to bypass the secondary fan, the secondary fan defining a secondary fan tip radius R.sub.3 and a secondary fan hub radius R.sub.4, wherein the secondary fan is configured to provide a fan duct airflow through the fan duct flowpath during operation to generate a fan duct thrust, wherein the fan duct thrust is equal to % Fn.sub.3S of a total engine thrust during operation of the gas turbine engine at a rated speed during standard day operating conditions; wherein a ratio of R.sub.1 to R.sub.3 equals

[00001]$\sqrt{\left(EFP\right)\frac{\left(1-{{\mathrm{RqR}}_{\mathrm{Sec}.-\mathrm{Fan}}}^2\right)}{\left(1-{{\mathrm{RqR}}_{\mathrm{Prim}.-\mathrm{Fan}}}^2\right)}\left(\frac{1}{\%{\mathrm{Fn}}_{3s}}-1\right)};$ wherein EFP is between 1.5 and 11, wherein RqR.sub.Prim.-Fan is a ratio of R.sub.1 to R.sub.2, and wherein RqR.sub.Sec.-Fan is a ratio of R.sub.3 to R.sub.4.

A propulsion system is provided including an unducted rotating fan defining a fan axis; and a turbomachine disposed downstream from the unducted rotating fan, wherein the turbomachine defines a working gas flowpath flowing therethrough; wherein the propulsion system defines a third stream flowpath and an inlet passage having an inlet that is offset from the fan axis, wherein the inlet passage is configured to provide an inlet airflow to the working gas flowpath, and wherein the third stream flowpath bypasses at least a portion of the turbomachine.

A fluid machine has: first and second walls; a gaspath defined between the first wall and the second wall; a rotor having blades rotatable about the central axis; and a stator having: a row of vanes having airfoils including leading edges, trailing edges, pressure sides and suction sides opposed the pressure sides, and depressions defined in the first wall, the depressions extending from a baseline surface of the first wall away from the second wall, a depression of the depressions located circumferentially between a pressure side of the pressure sides and a suction side of the suction sides, the depression axially overlapping the airfoils and extending in a downstream direction from an upstream end to a downstream end, the downstream end located closer to a trailing edge of the trailing edges than to a leading edge of the leading edges.

A gear assembly for use with a turbomachine comprises a sun gear, a plurality of planet gears, and a ring gear. The gear assembly is connected to an input shaft and an output shaft. The sun gear is configured to rotate about a longitudinal centerline of the gear assembly, and is driven by the input shaft. A component of the gear assembly drives the output shaft. The gear assembly further comprises an output shaft reversal mechanism configured to reverse the rotational direction of the output shaft.

A turboprop gas turbine engine mountable to an aircraft has an engine core and a gearbox driving a propeller, the engine core and the gearbox being enclosed within a nacelle. The propeller is located rearward of the gearbox and the engine core relative to a direction of travel of the aircraft. An air intake is disposed within the nacelle and formed to direct ambient air into the engine core. The air intake includes an air inlet duct, having a forward-facing intake inlet receiving the ambient air, with an upstream section and a downstream section. The upstream section is in fluid communication with the intake inlet and extends downstream from the intake inlet. The downstream section fluidly connects to and directs air from the upstream section into the engine air inlet. A second air outlet duct is located within the nacelle and directs air into an air-cooled-oil-cooler (ACOC).

The gas turbine engine for an aircraft includes at least a low pressure spool with a low pressure turbine shaft operatively connected to at least one turbine, the low pressure turbine shaft rotatable about an engine axis, and a low pressure compressor operatively connected to a low pressure compressor shaft that is independently rotatable relative to the low pressure turbine shaft. A differential gearbox has an input operatively connected to the low pressure turbine shaft, a first output and a second output, the first output of the differential gearbox operatively connected to the low pressure compressor shaft and the second output of the differential gearbox operatively connected to an output shaft of the gas turbine engine. The differential gearbox permits the output shaft, the low pressure compressor shaft and the low pressure turbine shaft to rotate at different speeds.

A gas turbine engine may include a high speed spool, a low speed spool, a first epicyclic gear system, and a second epicyclic gear system. Generally, the high speed spool mechanically connects a high pressure turbine to a high pressure compressor, and the low speed spool mechanically connects a low pressure turbine to at least one of a fan and a prop via the first epicyclic gear system and to a low pressure compressor via the second epicyclic gear system, according to various embodiments. The first epicyclic gear system and the second epicyclic gear system may include a common sun gear shaft.

A gas turbine engine has a housing exposed to a high temperature environment. The housing has a circumferential wall extending around the engine centerline and circumscribing an oil cavity. The wall has a sealing interface at an inner diameter thereof, the sealing interface having a central axis offset from the engine centerline. A boss is formed on the wall on the offset side relative to the engine centerline and a probe is mounted to the boss. The probe projects into the oil cavity. The oil in the oil cavity thermally shields the probe from the high temperature environment.

The main purpose of the invention is an air circulation device (1) for a turbomachine (10), comprising an air conveyance circuit (2, 4b, 9, 4a, 3) adapted to bring hot bleed air (A1) from the turbomachine (10) to a part to be heated (38), comprising a first segment fixed in rotation to a rotating part (31, 24) and comprising at least one hot air (A2) conveyance conduit (3, 9), and a hot air passage device (4a, 4b), comprising an annular compartment fixed in rotation to the first segment, characterise in that the annular compartment comprises a heat exchanger in contact with external air, and in that the hot air passage device (4a, 4b) comprises a hot air bypass system to deviate air entering into the device and to make it circulate along the heat exchanger when the temperature of this intake air is above a predetermined threshold.

An oil transfer unit has a rotating part extending along an axis, a stationary part provided with an oil mouth, and a floating part having a cylindrical surface fitted onto an outer cylindrical surface of the rotating part in a non-contact configuration; an annular groove is provided between the floating part and the rotating part to put the oil mouth into communication with an inner chamber of the rotating part; both sides of the groove are sealed by a hydrostatic seal defined by a radial gap between the cylindrical surfaces; the unit has at least one oil transfer tube, coupled to the stationary part and the floating part in a fluid-tight manner and with freedom of movement, and a connecting rod to prevent rotation of the floating part; the opposite ends of the connecting rod are coupled to the stationary part and floating part by respective spherical joints.