Flexible aft cowls for aircraft

Patent metadata

Field	Value
Publication number	US-11492998-B2
Application number	US-201916721157-A
Country	US
Kind code	B2
Filing date	Dec 19, 2019
Priority date	Dec 19, 2019
Publication date	Nov 8, 2022
Grant date	Nov 8, 2022

Abstract

Flexible aft cowls are disclosed. In some examples, an aircraft engine having a flexible aft cowl is disclosed. In some examples, the aircraft engine comprises an aft cowl having a flexible portion defining a throat area adjacent an engine core nozzle of the aircraft engine. In some examples, the flexible portion to move radially between a first radial position in response to pressure within a nacelle not exceeding a pressure threshold and a second radial position in response to pressure within the nacelle exceeding the pressure threshold. In some examples, the throat area defined by the flexible portion is greater when the flexible portion is in the second radial position than when the flexible portion is in the first radial position.

First claim

What is claimed is:

1. An aft cowl for an aircraft engine, the aft cowl comprising:
a flexible portion defining a throat area adjacent a discharge nozzle of an engine core of the aircraft engine, the flexible portion to move radially between a first radial position in response to pressure within a core compartment of the aircraft engine not exceeding a pressure threshold and a second radial position in response to pressure within the core compartment exceeding the pressure threshold, the throat area defined by the flexible portion being greater when the flexible portion is in the second radial position than when the flexible portion is in the first radial position, the flexible portion including:
a first skin segment;
a second skin segment;
a slot located between the first skin segment and the second skin segment; and
an axial hat stiffener having a first flange coupled to an inner surface of the first skin segment, a second flange spaced apart from the first flange and coupled to an inner surface of the second skin segment, and a body spanning across the slot and coupling the first flange and the second flange, the body extending in a radially inward direction away from the slot and toward the engine core.

2. The aft cowl of claim 1 , wherein the flexible portion moves in a radial direction away from the engine core as the flexible portion moves from the first radial position toward the second radial position.

3. The aft cowl of claim 1 , wherein the flexible portion moves in a radial direction toward the engine core as the flexible portion moves from the second radial position toward the first radial position.

4. The aft cowl of claim 1 , wherein the slot extends in an aft-fore direction a first distance from an aft edge of the aft cowl.

5. The aft cowl of claim 1 , wherein the flexible portion is supported by a radial standoff when the flexible portion is in the first radial position, wherein the radial standoff is supported by and extends radially outward from the engine core.

6. The aft cowl of claim 1 , wherein the flexible portion is composed of at least one of aluminum or titanium.

7. The aft cowl of claim 1 , wherein the pressure threshold is a burst duct pressure threshold of the core compartment.

8. The aft cowl of claim 1 , wherein the body has a first radius of curvature when the flexible portion is in the first radial position and a second radius of curvature greater than the first radius of curvature when the flexible portion is in the second radial position.

9. The aft cowl of claim 1 , further comprising a non-flexible portion having a first end and a second end located opposite the first end, the first end coupled to the flexible portion, the second end coupled to a pylon that supports the aircraft engine.

10. An aft cowl for an aircraft engine, the aft cowl comprising:
a flexible skin located radially outward from a discharge nozzle of an engine core of the aircraft engine, the flexible skin including:
a first skin segment;
a second skin segment; and
a slot located between the first skin segment and the second skin segment; and
an axial hat stiffener having a first flange coupled to an inner surface of the first skin segment, a second flange coupled to an inner surface of the second skin segment, and a body spanning across the slot and coupling the first flange and the second flange, the body extending in a radially inward direction away from the slot and toward the engine core;
wherein the axial hat stiffener enables radial movement of the flexible skin away from a first radial position and toward a second radial position when a pressure within a core compartment of the aircraft engine exceeds a pressure threshold and enables radial movement of the flexible skin away from the second radial position and toward the first radial position when the pressure within the core compartment does not exceed the pressure threshold.

11. The aft cowl of claim 10 , wherein the body has a first radius of curvature when the flexible skin is in the first radial position and a second radius of curvature greater than the first radius of curvature when the flexible skin is in the second radial position.

12. The aft cowl of claim 10 , further comprising a non-flexible skin having a first end and a second end located opposite the first end, the first end coupled to the flexible skin, the second end coupled to a pylon that supports the aircraft engine.

13. The aft cowl of claim 10 , wherein the flexible skin moves in a radial direction away from the engine core as the flexible skin moves from the first radial position toward the second radial position, and the flexible skin moves in a radial direction toward the engine core as the flexible skin moves from the second radial position toward the first radial position.

14. The aft cowl of claim 10 , wherein the flexible skin defines a throat area adjacent a discharge nozzle of the engine core, the throat area being greater when the flexible portion is in the second radial position than when the flexible portion is in the first radial position.

15. The aft cowl of claim 10 , wherein the flexible skin is supported by a radial standoff when the flexible skin is in the first radial position, wherein the radial standoff is supported by and extends radially outward from the engine core.

16. An aircraft engine, comprising:
an engine core having an outer surface;
an inner wall located radially outward from the outer surface of the engine core, the inner wall having an inner surface;
a core compartment defined by the outer surface of the engine core and the inner surface of the inner wall;
a fluid device configured to extract bleed air from an engine compressor of the aircraft engine;
a conduit in fluid communication with the fluid device, the conduit configured to route extracted bleed air from the fluid device to an aircraft system to be powered by the aircraft engine, the conduit including a portion located within the core compartment, wherein the extracted bleed air is to enter the core compartment in response to a burst event associated with the portion of the conduit; and
an aft cowl located adjacent the inner wall, the aft cowl including a flexible portion defining a throat area adjacent a discharge nozzle of the engine core, the flexible portion to move radially between a first radial position in response to pressure within the core compartment not exceeding a burst pressure threshold and a second radial position in response to pressure within the core compartment exceeding the burst pressure threshold, the throat area being greater when the flexible portion is in the second radial position than when the flexible portion is in the first radial position, the burst pressure threshold corresponding to an increase in pressure that occurs within the core compartment in response to the burst event;
wherein the flexible portion includes:
a first skin segment;
a second skin segment;
a slot located between the first skin segment and the second skin segment; and an axial hat stiffener having a first flange coupled to an inner surface of the first skin segment, a second flange spaced apart from the first flange and coupled to an inner surface of the second skin segment, and a body coupling the first flange and the second flange, the body spanning across the slot, the body extending in a radially inward direction away from the slot and toward the engine core.

17. The aircraft engine of claim 16 , wherein the flexible portion is supported by a radial standoff when the flexible portion is in the first radial position, wherein the radia

Assignees

• Boeing Co

Inventors

• Torjesen Luke D

Classifications

• F02K1/82

  Jet pipe walls, e.g. liners · CPC title

• F02K1/10 Primary

  by distorting the jet pipe or nozzle · CPC title

• F01D25/30

  Exhaust heads, chambers, or the like · CPC title

• F05D2260/38

  by a spring, i.e. spring loaded or biased towards a certain position · CPC title

• F02K3/06

  with front fan · CPC title