Sound suppressing nacelle arrangement

Claim 2

A sound suppressing nacelle arrangement housing a gas turbine engine for propulsion of a winged aircraft comprises: a nacelle mounted over the wing of the aircraft with an opening at the upstream end thereof for receipt of an inlet airflow to the gas turbine engine, said wing including a trough-like surface; an exhaust duct translatably disposed in serial flow relation downstream of the nacelle for telescoping engagement within the nacelle, and means for translating the exhaust duct forwardly over the wing to expose rearwardly of the exhaust duct a portion of the nacelle overlying said trough-like surface of the wing, said trough-like surface operating as a sound reflecting shield when said exhaust duct is in its forward position.

Claim 3

The sound suppressing nacelle arrangement of claim 1 wherein the downstream end of the translating exhaust duct terminates in a variable exhaust nozzle comprising: a plurality of circumferentially spaced apart flaps rotatably hinged to the downstream edge of the exhaust duct; a plurality of circumferentially spaced apart actuators each one of which interconnects between the exhaust duct and a respective rotatable flap; a flexible circumferential drive shaft extending around the exhaust duct into driving engagement with all the actuators; a pinion gear in fixed connection to the drive shaft, and a rack maintained in fixed relation relative to the nacelle such that upstream translation of the exhaust duct results in the teeth of the pinion gear engaging the teeth of the rack so as to rotate the pinion gear and its associated drive shaft and simultaneously actuate the actuators which pivot the flaps radially outward increasing the exit area of the variable exhaust nozzle.

Claim 4

The sound suppressing nacelle arrangement of claim 2 wherein each actuator is of the screw type housed within an outer fairing so as to minimize the disturbance of the aerodynamic flow around the actuators.

Claim 5

The sound suppressing nacelle arrangement of claim 1 wherein the trailing edge of the nacelle gradually tapers rearwardly so as to define an elongated trough-like surface over the wing, said surface functioning as a concave sound reflecting shield during upstream translation of the exhaust duct into telescoping engagement within the nacelle.

Claim 6

The sound suppressing nacelle arrangement of claim 1 and further including: a pair of elongated dovetail channels, extending generally axially in the nacelle in the portion overlying the wing; a pair of elongated dovetail rails, extending generally axially along the exhaust duct, each of said rails slidably engaging a corresponding dovetail channel for translation of the exhaust duct with respect to the nacelle; roller bearinGs, disposed in sets at axially spaced locations along the length of the channels to facilitate sliding engagement between the rails and the channels; an actuator for controlling translation of the exhaust duct, one end of said actuator being maintained in fixed connection relative to the nacelle and the other end thereof being connected to the exhaust duct.

Claim 7

A sound suppressing nacelle arrangement housing a gas turbine engine for propulsion of a winged aircraft comprises: a nacelle mounted over the wing of the aircraft having an opening at the upstream end thereof for receipt of an inlet airflow to the gas turbine engine with the downstream edge thereof tapering rearwardly so as to define an elongated trough-like surface over the wing, said surface functioning as a concave sound reflecting shield; an exhaust duct translatably disposed in serial flow relation downstream of the nacelle whereby the exhaust duct may be translated forwardly over the wing exposing the concave sound reflecting shield, and a variable exhaust nozzle at the downstream end of the translating exhaust duct comprising: a plurality of circumferentially spaced apart flaps rotatably hinged to the downstream edge of the exhaust duct, a plurality of circumferentially spaced apart actuators each one of which interconnects between the exhaust duct and a respective rotatable flap, a flexible circumferential drive shaft extending around the exhaust duct into driving engagement with all the actuators, a pinion gear in fixed connection to the drive shaft, and a rack maintained in fixed relation relative to the nacelle such that upstream translation of the exhaust duct results in the teeth of the pinion gear engaging the teeth of the rack so as to rotate the pinion gear and its associated drive shaft and simultaneously actuate the actuators which pivot the flaps radially outward increasing the exit area of the variable exhaust nozzle.

Claim 8

A sound suppressing nacelle arrangement housing a gas turbine engine for propulsion of a winged aircraft comprises: a nacelle mounted over the wing of the aircraft having an opening at the upstream end thereof for receipt of an inlet airflow to the gas turbine engine with the downstream edge thereof tapering rearwardly so as to define an elongated trough-like surface over the wing, said surface functioning as a concave sound reflecting shield; an exhaust duct translatably disposed in serial flow relation downstream of the nacelle whereby the exhaust duct may be translated forwardly over the wing exposing the concave sound reflecting shield, and a variable exhaust nozzle at the downstream end of the translating exhaust duct comprising: a plurality of circumferentially spaced apart flaps rotatably hinged to the downstream edge of the exhaust duct, a plurality of circumferentially spaced apart actuators each one of which interconnects between the exhaust duct and a respective rotatable flap, a flexible circumferential drive shaft extending around the exhaust duct into driving engagement with all the actuators, a pinion gear in fixed connection to the drive shaft, and a rack maintained in fixed relation relative to the nacelle such that upstream translation of the exhaust duct results in the teeth of the pinion gear engaging the teeth of the rack so as to rotate the pinion gear and its associated drive shaft and simultaneously actuate the actuators which pivot the flaps radially outward increasing the exit area of the variable exhaust nozzle.

Claim 9

The sound suppressing nacelle arrangement of claim 6 wherein: the exhaust duct is maintained for translation with respect to the nacelle by a pair of elongated, generally axially extending rails from the exhaust duct which respectively engage elongated, generally axially extending dovetail channels in the nacelle with sliding engagement between the dovetail rails and dovetail channels facilitated by roller bearings disposed in sets at axially spaced apart locations along the longitudinal length of the dovetail channels and translation of the exhaust duct is controlled by an actuator, one end of which is maintained in fixed connection relative to the nacelle with the other end thereof connecting to the exhaust duct.