A jet engine which includes: a fan with a plurality of stages of rotor blades; a compressor compressing air sent from the fan; a combustor generating combustion gas by using compressed air generated by the compressor; a turbine generating a driving force from the combustion gas; a nozzle discharging the combustion gas; a variable guide vane disposed upstream of the rotor blades of a second and later stage of the rotor blades of the fan and adjusts an inlet angle of air flow against the second and later stage of the rotor blades; a fluid resistance adjusting device adjusting a fluid resistance at the nozzle; and a controller which controlling the variable guide vane such that the inlet angle at the time of cruise flight is smaller than the inlet angle at the time of acceleration.

The present disclosure relates to a method of operating a supersonic aircraft comprising the steps of: at takeoff, positioning a slidable plug-cowl assembly disposed within a nozzle and behind an engine in an aft position such that a front surface of a plug is aft of an exit plane of a cowl, to thereby reduce noise during takeoff and maintain engine efficiency; and after takeoff, re-positioning the slidable plug-cowl assembly to a forward position such that the front surface of the plug is not disposed aft the exit plane of the cowl.

The present disclosure relates to a method of operating a supersonic aircraft comprising the steps of: at takeoff, positioning a slidable plug-cowl assembly disposed within a nozzle and behind an engine in an aft position such that a front surface of a plug is aft of an exit plane of a cowl, to thereby reduce noise during takeoff and maintain engine efficiency; and after takeoff, re-positioning the slidable plug-cowl assembly to a forward position such that the front surface of the plug is not disposed aft the exit plane of the cowl.

In accordance with one aspect of the disclosure, a gas turbine engine, method of using and designing such is disclosed. The gas turbine engine may comprise a fan including a plurality of blades, and a variable area fan nozzle. The fan may be configured to have a design point fan tip leading edge relative flow angle .sub.ADP, and may be further configured to have an off-design point fan tip leading edge relative flow angle at an off-design fan operating point. The variable area fan nozzle may be configured to manipulate the amount of air flowing through the fan so that the absolute value of a difference between the design point fan tip leading edge relative flow angle .sub.ADP and the off-design point fan tip leading edge relative flow angle is in a specified range.

In accordance with one aspect of the disclosure, a gas turbine engine, method of using and designing such is disclosed. The gas turbine engine may comprise a fan including a plurality of blades, and a variable area fan nozzle. The fan may be configured to have a design point fan tip leading edge relative flow angle .sub.ADP, and may be further configured to have an off-design point fan tip leading edge relative flow angle at an off-design fan operating point. The variable area fan nozzle may be configured to manipulate the amount of air flowing through the fan so that the absolute value of a difference between the design point fan tip leading edge relative flow angle .sub.ADP and the off-design point fan tip leading edge relative flow angle is in a specified range.

An aspect includes a variable cycle system of a gas turbine engine. The variable cycle system includes an actuation system, an electric component, and a controller. The actuation system is configured to adjust a variable cycle of turbomachinery of the gas turbine engine. The electric component is operable to provide a shaft power supply or a load corresponding respectively to an adjustment of the turbomachinery. The controller is operable to adjust an output of either or both of the actuation system and the electric component for separate control of thrust and cycle responses.

A jet vectoring apparatus has a nozzle (1) which comprises a throat aperture (8) and an exit aperture (9), the apparatus also having a post exit surface (10). Variation of at least one of the throat aperture (8), exit aperture (9) and post exit surface causes a pressure differential upon the post exit surface which permits the direction of propulsive jet flow (3) (also known as jet thrust) to be varied relative to the longitudinal axis (2) of the apparatus.

An aircraft includes a jet engine and a telescopic tube assembly positioned on the jet engine. The telescopic tube assembly includes one end portion of the telescopic tube assembly which is associated with a thrust reverser translating sleeve of the jet engine and an opposing end portion of the telescopic tube assembly which is associated with a fixed portion of the of the jet engine. A jet engine includes a telescopic tube assembly positioned on the jet engine. The telescopic tube assembly includes one end portion of the telescopic tube assembly which is associated with a thrust reverser translating sleeve of a jet engine and an opposing end portion of the telescopic tube assembly which is associated with a fixed portion of the of the jet engine.

An aircraft includes a jet engine and a telescopic tube assembly positioned on the jet engine. The telescopic tube assembly includes one end portion of the telescopic tube assembly which is associated with a thrust reverser translating sleeve of the jet engine and an opposing end portion of the telescopic tube assembly which is associated with a fixed portion of the of the jet engine. A jet engine includes a telescopic tube assembly positioned on the jet engine. The telescopic tube assembly includes one end portion of the telescopic tube assembly which is associated with a thrust reverser translating sleeve of a jet engine and an opposing end portion of the telescopic tube assembly which is associated with a fixed portion of the of the jet engine.

An exhaust gas diffuser for a gas turbine engine whose inlet geometry can be selectively controlled to change the angular orientation of the diffuser at the location where the exhaust gas exits the last stage row of blades of the turbine section of the gas turbine engine. An end portion of the gas diffuser proximate the last stage row of blades can include one or more actuated sections that are independently controlled to change the angular orientation of the inlet geometry of the diffuser. In one embodiment, the angular orientation of the actuated sections is set at the manufacturing level for the service location of the engine. In another embodiment, the angular orientation of the actuated sections is selectively controlled based on the operating conditions of the engine. In another embodiment, the angular orientation of the actuated sections is controlled by pneumatic pressure from a compressor section of the engine.