An aircraft engine comprising a fan, the fan having a diameter D and including a plurality of fan blades, the fan blades having a sweep metric S.sub.tip, each fan blade having a leading edge, and a forward-most portion on the leading edge of each fan blade being in a first reference plane. The aircraft engine further comprises a nacelle, comprising an intake portion forward of the fan, a forward edge on the intake portion being in a second reference plane, wherein the intake portion has a length L measured along an axis of the aircraft engine between the first reference plane and the second reference plane, the aircraft engine having a cruise design point condition M.sub.rel, wherein M.sub.rel is between 0.4 and 0.93, L/D is between 0.2 and 0.45 and S.sub.tip is from −1 to 0.1.

This invention relates to a multi-stage rotor (10). More specifically, the invention relates to a multistage rotor (10) for the compressor stage of a machine that, through a concentric configuration of its innermost (12), outermost (24) and intermediary (16) blade sets co-operative with a reverse flow convoluting ducting arrangement, provides an axially compact, lighter and more easily maintainable compressor rotor for such machine. The multi-stage rotor (10) includes innermost (30), outermost (34) and intermediary (32) duct ports comprising a radial duct spans, as measured between respective diametrically inner and outer duct walls of the duct port, being greater than respective innermost (48), outermost (54) and intermediary (50, 52) radial blade spans of the respective blade sets rotatable at least partially within such duct port. In this manner, a gap is defined between: (i) the at least one diametrical ends of the radial rotating blades ending radially short of the respective radial duct span to form free ends of the blades; and (ii) a stationary part of the respective duct the free ends of the blades sweep neared to; for generating a friction wash between such free ends of the blades and the stationary part of the respective duct.

The invention relates to a jet engine with a fixed housing in which a primary flow is formed in which incoming air is burned in at least one combustion chamber, in said housing a secondary flow being formed in which incoming air is accelerated by a fan and, said secondary flow being expelled at the outlet cone of the housing together with the exhaust gas from the combustion chamber, said fan being mounted on a main shaft rotatably about an axis and having a plurality of substantially radially-extending fan blades. According to the invention, it is proposed that at least one fan blade or a plurality of the fan blades or all fan blades have at least one air inlet channel for the primary flow which directs the air of the primary flow through the fan blade to the combustion chamber, and that at least one fan blade or a plurality of the fan blades or all fan blades each have an outlet channel with an at least partially axially- and at least partially tangentially-oriented outlet opening in order to supply the exhaust gas of the combustion chambers to the accelerated air of the secondary flow, said air-exhaust gas mixture emerging at the outlet cone of the jet engine housing, producing the thrust.

The invention relates to a jet engine with a fixed housing in which a primary flow is formed in which incoming air is burned in at least one combustion chamber, in said housing a secondary flow being formed in which incoming air is accelerated by a fan and, said secondary flow being expelled at the outlet cone of the housing together with the exhaust gas from the combustion chamber, said fan being mounted on a main shaft rotatably about an axis and having a plurality of substantially radially-extending fan blades. According to the invention, it is proposed that at least one fan blade or a plurality of the fan blades or all fan blades have at least one air inlet channel for the primary flow which directs the air of the primary flow through the fan blade to the combustion chamber, and that at least one fan blade or a plurality of the fan blades or all fan blades each have an outlet channel with an at least partially axially- and at least partially tangentially-oriented outlet opening in order to supply the exhaust gas of the combustion chambers to the accelerated air of the secondary flow, said air-exhaust gas mixture emerging at the outlet cone of the jet engine housing, producing the thrust.

A gas turbine engine has a compression system radius ratio defined as the ratio of the radius of the tip of a fan blade to the radius of the tip of the most downstream compressor blade in the range of from 5 to 9. This results in an optimum balance between installation benefits, operability, maintenance requirements and engine efficiency when the gas turbine engine is installed on an aircraft.

A gas turbine engine has a compression system radius ratio defined as the ratio of the radius of the tip of a fan blade to the radius of the tip of the most downstream compressor blade in the range of from 5 to 9. This results in an optimum balance between installation benefits, operability, maintenance requirements and engine efficiency when the gas turbine engine is installed on an aircraft.

A gas turbine engine has a compression system radius ratio defined as the ratio of the radius of the tip of a fan blade to the radius of the tip of the most downstream compressor blade in the range of from 5 to 9. This results in an optimum balance between installation benefits, operability, maintenance requirements and engine efficiency when the gas turbine engine is installed on an aircraft.

A gas turbine engine has a compression system radius ratio defined as the ratio of the radius of the tip of a fan blade to the radius of the tip of the most downstream compressor blade in the range of from 5 to 9. This results in an optimum balance between installation benefits, operability, maintenance requirements and engine efficiency when the gas turbine engine is installed on an aircraft.

A nacelle for a gas turbine engine having a longitudinal centre line. The nacelle includes an air intake disposed at an upstream end of the nacelle. The air intake includes, in flow series, an intake lip, a throat and a diffuser. The diffuser further includes a diffuser angle (θ.sub.diff), indicating a degree of divergence of the diffuser relative to the longitudinal centre line. The diffuser angle (θ.sub.diff) is from about 0 degrees to about 12 degrees.

A nacelle for a gas turbine engine having a longitudinal centre line. The nacelle includes an air intake disposed at an upstream end of the nacelle. The air intake includes, in flow series, an intake lip, a throat and a diffuser. The nacelle further includes a protrusion extending radially inward from the air intake downstream of the intake lip. The protrusion extends circumferentially by a protrusion angle (θ.sub.p) with respect to the longitudinal centre line of the gas turbine engine.