Hidden thrust reverser blocker door link arm fitting

A linkage system for a nacelle may comprise a pivot configured to extend through a second aperture disposed in a link arm, a base member, and a retaining member at least partially defining a first aperture and a cavity. The pivot is configured to extend at least partially into the first aperture. The cavity is configured to accommodate a portion of the link arm.

FIELD

This disclosure relates generally to gas turbine engines, and more particularly to thrust reverser assemblies for gas turbine engines.

BACKGROUND

Generally, a thrust reverser blocker door link arm attaches to a fan duct inner fixed structure (IFS) via a fitting attached to the surface of the IFS. The thrust reverser blocker door may rotate about the fitting to a deployed position, blocking fan duct air and causing reverse thrust. These features (i.e., the fitting and the link arm) may cause duct losses and may reduce thrust specific fuel consumption (TSFC).

SUMMARY

A linkage system for a nacelle may comprise a pivot configured to extend through a second aperture disposed in a link arm, a base member, and a retaining member at least partially defining a first aperture and a cavity, wherein the pivot is configured to extend at least partially into the first aperture, and wherein the cavity is configured to accommodate a portion of the link arm.

In various embodiments, the base member may be configured to be attached to an inner fixed structure (IFS) of the nacelle. The link arm may comprise a thrust reverser link arm. The first aperture may extend in a direction substantially orthogonal to the cavity. The retaining member may be configured to retain the link arm to the base member. The retaining member may define a first portion of the first aperture and the base member may define a second portion of the first aperture, wherein the pivot is retained within the first aperture in response to the retaining member being fastened to the base member. The retaining member may comprise an attachment aperture extending substantially orthogonal to the first aperture, the attachment aperture configured to accommodate a fastener for fastening the base member to the retaining member. The first portion may comprise a first half and the second portion comprises a second half. The cavity may comprise a high aspect ratio aperture.

A nacelle for a gas turbine engine may comprise an inner fixed structure (IFS) comprising a proximal layer and a distal layer, a link arm having a first end and a second end, wherein a second aperture is disposed in the link arm at the first end, the link arm configured to rotate about the second aperture, and a fitting arrangement for the link arm comprising a pivot extending through the second aperture, a base member attached to the proximal layer, and a retaining member at least partially defining a first aperture and a cavity, wherein the pivot is located at least partially within the first aperture, at least a portion of the pivot extends through the second aperture of the link arm, wherein the first end of the link arm is located at least partially within the cavity, and wherein the retaining member is substantially flush with the distal layer.

In various embodiments, the link arm may comprise a thrust reverser link arm. The first aperture may extend in a direction substantially orthogonal to the cavity. The retaining member may retain the link arm to the base member. A distal surface of the distal layer may at least partially define a bypass flow path. The base member may be attached to the proximal layer of the IFS via an adhesive. The retaining member may define a first portion of the first aperture and the base member may define a second portion of the first aperture, wherein the pivot is retained within the first aperture in response to the retaining member being fastened to the base member. The retaining member may comprise an attachment aperture extending substantially orthogonal to the first aperture, the attachment aperture configured to accommodate a fastener for fastening the base member to the retaining member. The base member may comprise a slot, at least a portion of the first end extending into the slot.

A method of installing a linkage system to a nacelle may comprise attaching a base member to an inner fixed structure (IFS), placing a pivot at least partially into a second aperture disposed in a link arm, placing the pivot at least partially into a first aperture disposed in a fitting arrangement, positioning the second aperture and the first aperture in concentric alignment, and attaching a retaining member to the base member, the retaining member defining at least a portion of the first aperture and defining at least a portion of a cavity, at least a portion of the link arm being located within the cavity.

In various embodiments, the method may be performed from a bypass flow path of the nacelle.

DETAILED DESCRIPTION

As used herein, “distal” refers to the direction radially outward, or generally, away from the axis of rotation of a turbine engine. As used herein, “proximal” refers to a direction radially inward, or generally, towards the axis of rotation of a turbine engine.

FIG. 1illustrates a schematic view of a gas turbine engine, in accordance with various embodiments. An xyz-axis is provided for ease of illustration. Gas turbine engine110may include core engine120. Core air flow C flows through core engine120and is expelled through exhaust outlet118surrounding tail cone122.

Core engine120drives a fan114arranged in a bypass flow path B. Air in bypass flow-path B flows in the aft direction (z-direction) along bypass flow-path B. At least a portion of bypass flow path B may be defined by nacelle112and inner fixed structure (IFS)126. Fan case132may surround fan114. Fan case132may be housed within fan nacelle112.

Nacelle112typically comprises two halves which are typically mounted to a pylon. According to various embodiments, multiple guide vanes116may extend radially between core engine120and fan case132. Upper bifurcation144and lower bifurcation142may extend radially between the nacelle112and IFS126in locations opposite one another to accommodate engine components such as wires and fluids, for example.

Inner fixed structure126surrounds core engine120and provides core compartments128. Various components may be provided in core compartment128such as fluid conduits and/or compressed air ducts, for example.

With reference toFIG. 2A, a side view of gas turbine engine110is illustrated, in accordance with various embodiments. Gas turbine engine110may comprise a turbofan engine. Gas turbine engine110may be mounted onto an aircraft by pylon212. Gas turbine engine110may include segmented cowl213which includes nacelle body214and translating cowl216and IFS126(seeFIG. 1). Translating cowl216is split from nacelle body214and translates aft to produce reverse thrust.

A plurality of cascade vane sets222may be uncovered in response to translating cowl216being translated aft as seen inFIG. 2A. Each of cascade vane sets222may include a plurality of conventional transverse, curved, turning vanes which turn airflow passing out from bypass flow path B (seeFIG. 1) through the cascade sets in an outwardly and forwardly direction relative to gas turbine engine110. Islands224are provided between cascade vane sets222to support the translation of translating cowl216and support the sides of cascade vane sets222. In the stowed position, translating cowl216is translated forwardly to cover cascade vane sets222and provide a smooth, streamlined surface for air flow during normal flight operations.

With reference toFIG. 2B, a cross-section view of gas turbine engine110with blocker door228in a stowed position is illustrated, in accordance with various embodiments. Cascade230shown inFIG. 2Bis just one of many cascade vane sets222disposed circumferentially around gas turbine engine110as shown inFIG. 2A. An actuator268may be disposed between these sets of cascades in order to drive translating cowl216in the aft direction. After a thrust reversing operation is completed, actuators268may return blocker door228to the stowed position. Actuator268can be a ball-screw actuator, hydraulic actuator, or any other actuator known in the art. In various embodiments, multiple actuators268are spaced around gas turbine engine110in between cascade vane sets222. Although illustrated inFIG. 2BandFIG. 2Cas being radially in-line with cascade230, actuator268may be located radially inward, radially outward, or in any location relative to cascade230.

Blocker door (also referred to herein as thrust reverser blocker door)228may be engaged with translating cowl216. In various embodiments, blocker door228may be engaged with translating cowl216through bracket270. In various embodiments, bracket270and translating cowl216may comprise a single, unitary member. Pivot272may be a hinge attachment between blocker door228and bracket270. In various embodiments, blocker door228may be engaged directly to translating cowl216through a hinge attachment. Pivot272may allow blocker door228to rotate as translating cowl216moves from a stowed position to a deployed position.

With combined reference toFIG. 2BandFIG. 2C, a linkage system232may be coupled between IFS126and blocker door228. Linkage system232may include fitting arrangement (also referred to herein as fitting)200and link arm (also referred to herein as a thrust reverser link arm)256. Fitting200may be coupled to IFS126. Link arm256may be configured to pivot about fitting200. Stated another way, first end252of link arm256may be rotatably coupled to fitting200. Second end254of link arm256may be rotatably coupled to blocker door228.

Fitting200may extend through an aperture disposed in IFS126such that fitting200does not extend into bypass flow-path B, allowing a more efficient flow of bypass air in bypass flow-path B. Stated another way, fitting200may be located such that fitting200does not extend radially outward of distal surface (also referred to herein as flow surface)204of IFS126. Distal surface204may partially define bypass flow-path B. In this manner, the thrust specific fuel consumption (TSFC) of the gas turbine engine onto which fitting200is installed may be increased, in accordance with various embodiments.

With respect toFIG. 2C, elements with like element numbering, as depicted inFIG. 2B, are intended to be the same and will not necessarily be repeated for the sake of clarity.

With reference toFIG. 2C, a cross-section view of gas turbine engine110with blocker door228in a deployed position is illustrated, in accordance with various embodiments. Thus,FIG. 2Cshows gas turbine engine110in a reverse thrust mode. Blocker door228and its associated linkage system232are responsive to translation of translating cowl216during a thrust reversing sequence. As noted above and with momentary additional reference toFIG. 1,FIG. 2Bshows a normal or cruise mode where fan air is directed through bypass flow path B. When in a deployed position, shown inFIG. 2C, bypass flow path B is blocked by one or more circumferentially disposed blocker doors228, interposed within bypass flow path B and collectively having a complementary geometric configuration with respect thereto, for diversion of fan air into bypass duct246. The reverse thrust mode is achieved by aftward movement of translating cowl216, thereby exposing outlet port274for airflow to escape through after the air passes into bypass duct246.

With respect toFIG. 2D, elements with like element numbering, as depicted inFIG. 2BandFIG. 2C, are intended to be the same and will not necessarily be repeated for the sake of clarity.

With reference toFIG. 2D, a perspective view of link arm256in the stowed position (also referred to as a normal cruise mode)292and the deployed position (also referred to as a reverse thrust mode)294is illustrated, in accordance with various embodiments. Stated another way, a perspective view of blocker door228in the stowed position292and the deployed position294is illustrated, in accordance with various embodiments. In various embodiments, fitting200may be flush with distal surface204when fitting200is in the installed position as illustrated inFIG. 2D. In various embodiments, fitting200may be disposed radially inward of distal surface204when fitting200is in the installed position as illustrated inFIG. 2D.

With respect toFIG. 3AandFIG. 3B, elements with like element numbering, as depicted inFIG. 2BandFIG. 2C, are intended to be the same and will not necessarily be repeated for the sake of clarity.

With reference toFIG. 3A, a close-up, cross-sectional view of linkage system232in a deployed position294as well as in a stowed position292is illustrated, in accordance with various embodiments. A yz-axes is provided for ease of illustration. Fitting200may be coupled to IFS126. IFS126may comprise a distal layer380and a proximal layer390. In various embodiments, distal layer380may comprise a composite sheet or may comprise a metallic sheet. In various embodiments, proximal layer390may comprise a composite sheet or may comprise a metallic sheet. Distal layer380may comprise a distal surface204and a proximal surface382. Proximal layer390may comprise a distal surface394and a proximal surface392.

In various embodiments, fitting200may include pivot330, base member310, and retaining member320. Fitting200may include first end326and second end328. Fitting200may include fastener314. In various embodiments, fastener314may fasten retaining member320to base member310. In various embodiments, base member310may be coupled to IFS126via an adhesive. In various embodiments, base member310may be coupled to IFS126via a fastener. In various embodiments, base member310may be integrally formed with IFS126such as during a composite co-curing process. Base member310may prevent retaining member320from moving relative to IFS126.

With reference toFIG. 3B, a perspective, cross-section view of linkage system232in a deployed position294(also referred to as a reverse thrust mode) as well as in a stowed position292(also referred to as a forward thrust mode) is illustrated, in accordance with various embodiments. An xyz-axes is provided for ease of illustration. First end252of link arm256may comprise an aperture (also referred to herein as a second aperture)304. With momentary reference toFIG. 4A, retaining member320may define an aperture (also referred to herein as a first aperture)402. Pivot330may extend through aperture402. Pivot330may be coupled to retaining member320via aperture402. Pivot330may extend through aperture304of link arm256. Link arm256may be pivotally coupled to retaining member320via pivot330. In this regard, retaining member320may retain link arm256to base member310. In this regard, fitting200may retain link arm256to IFS126.

Retaining member320may define a cavity342. In various embodiments, cavity342may comprise a high aspect ratio aperture. A high aspect ratio aperture may comprise an aperture having an aspect ratio greater than 1.5, and in various embodiments, an aspect ratio greater than 2, and in various embodiments, an aspect ratio greater than 3, wherein aspect ratio, in this regard, refers to the ratio of the width of cavity342(measured along the z-direction in the xz-plane) and the height of cavity342(measured along the x-direction in the xz-plane). First end252of link arm256may be located within cavity342. In various embodiments, base member310may define a portion of cavity342. In various embodiments, the aspect ratio of cavity342may be sized to accommodate rotation of link arm256.

In various embodiments, fitting200may comprise a metal such as a steel alloy, stainless steel, titanium, aluminum, or any other metal. In various embodiments, fitting200may comprise a composite material. Pivot330may comprise steel or stainless steel. In various embodiments, pivot330may comprise aluminum. Pivot330may include a steel sleeve in response to pivot330comprising aluminum.

With reference toFIG. 3B, base member310may comprise a slot308. A portion of first end252of link arm256may extend into slot308. In various embodiments, slot308may comprise a high aspect ratio aperture. Slot308may accommodate the rotation of link arm256. In various embodiments, slot308may extend entirely through base member310. In various embodiments, slot308may extend through only a portion of base member310.

With respect toFIG. 4AthroughFIG. 5B, elements with like element numbering, as depicted inFIG. 3AandFIG. 3B, are intended to be the same and will not necessarily be repeated for the sake of clarity.

With combined reference toFIG. 4AandFIG. 4B, linkage system432is illustrated, in accordance with various embodiments. In various embodiments, linkage system432may be similar to linkage system232(seeFIG. 3A). Linkage system432may include fitting400split at location492. Fitting400may include retaining member420, base member410, and pivot430. Base member410may comprise a raised portion412. The geometry of raised portion412may be complementary to the geometry of retaining member420. Base member410may further comprise a plate414. Raised portion412may extend from plate414. In various embodiments, raised portion412may orthogonally extend from plate414.

Pivot430may comprise a first portion436and a second portion438. The first portion436may be threadingly coupled to the second portion438. In various embodiments, pivot430may be a bearing. In various embodiments, pivot430may comprise a rod, pin, or the like. Although illustrated as comprising two separate pieces, it is contemplated that pivot430may comprise a single unitary member.

In various embodiments, pivot430may be compressed between retaining member420and base member410. In this regard, retaining member may define a first portion481of aperture402and base member410may define a second portion482of aperture402. A plurality of fasteners484may couple retaining member420to base member410via attachment apertures486. Pivot430may be compressed between retaining member420and base member410in response to tightening fasteners484. Fasteners484may be counter-sunk into retaining member420such that fasteners484do not extend above distal surface496of retaining member420.

With combined reference toFIG. 5AandFIG. 5B, linkage system532is illustrated, in accordance with various embodiments. In various embodiments, linkage system532may be similar to linkage system232(seeFIG. 3A). Linkage system532may include fitting500split at location592. Fitting500may include retaining member520, base member510, and pivot530. Base member510may comprise a raised portion512. The geometry of raised portion512may be complementary to the geometry of retaining member520. Base member510may further comprise a plate514. Raised portion512may extend from plate514. In various embodiments, raised portion512may orthogonally extend from plate514. In various embodiments, retaining member520may define cavity542.

Pivot530may comprise a first portion536and a second portion538. The first portion536may be threadingly coupled to the second portion538. In various embodiments, pivot530may be a bearing. In various embodiments, pivot530may comprise a rod, pin, or the like.

With combined reference toFIGS. 6A and 6B, a linkage system632is illustrated, in accordance with various embodiments. Linkage system632may be similar to linkage system432(seeFIG. 4A). Linkage system632may include fitting600. Fitting600may include retaining member620and base member610. A plurality of rods684may extend through fitting600. Pockets688may be formed into fitting600on proximal surface691of fitting600. Pockets688may accommodate flanged portion685of rods684. Rods684may comprise threaded portions. Fasteners686may be coupled to rods684to couple retaining member620to base member610.

In various embodiments, fasteners686may be circumferentially offset (in the x-direction) from link arm256as illustrated inFIG. 6B. Linkage system632may comprise four fasteners as illustrated inFIG. 6B.

In various embodiments, with reference toFIG. 6C, fasteners686may be axially in line (along the z-direction) with link arm256as illustrated inFIG. 6C. In this regard, linkage system632may comprise two fasteners as illustrated inFIG. 6C. Aligning fasteners686with link arm256may provide a more streamline linkage system632.

With reference toFIG. 7, a method700of installing a linkage system to a nacelle is provided, in accordance with various embodiments. Method700includes attaching a base member to an inner fixed structure (IFS) (step710). Method700includes placing a pivot into a second aperture disposed in a thrust reverser link arm (step720). Method700includes placing the pivot into a first aperture disposed in a fitting arrangement (step730). Method700includes positioning the first aperture and a second aperture in concentric alignment (step740). Method700includes attaching a retaining member to the base member (see step550).

In various embodiments, method700may be performed without having to open the thrust reverser blocker door228(seeFIG. 2B). In various embodiments, method500may be performed without having to access the core compartment128(seeFIG. 1). In various embodiments, method500may be performed by accessing bypass flow path B (seeFIG. 1).

Benefits, other advantages, and solutions to problems have been described herein with regard to specific embodiments. Furthermore, the connecting lines shown in the various figures contained herein are intended to represent exemplary functional relationships and/or physical couplings between the various elements. It should be noted that many alternative or additional functional relationships or physical connections may be present in a practical system. However, the benefits, advantages, solutions to problems, and any elements that may cause any benefit, advantage, or solution to occur or become more pronounced are not to be construed as critical, required, or essential features or elements of the disclosure. The scope of the disclosure is accordingly to be limited by nothing other than the appended claims, in which reference to an element in the singular is not intended to mean “one and only one” unless explicitly so stated, but rather “one or more.” Moreover, where a phrase similar to “at least one of A, B, or C” is used in the claims, it is intended that the phrase be interpreted to mean that A alone may be present in an embodiment, B alone may be present in an embodiment, C alone may be present in an embodiment, or that any combination of the elements A, B and C may be present in a single embodiment; for example, A and B, A and C, B and C, or A and B and C. Systems, methods and apparatus are provided herein. In the detailed description herein, references to “one embodiment”, “an embodiment”, “various embodiments”, etc., indicate that the embodiment described may include a particular feature, structure, or characteristic, but every embodiment may not necessarily include the particular feature, structure, or characteristic. Moreover, such phrases are not necessarily referring to the same embodiment. Further, when a particular feature, structure, or characteristic is described in connection with an embodiment, it is submitted that it is within the knowledge of one skilled in the art to affect such feature, structure, or characteristic in connection with other embodiments whether or not explicitly described. After reading the description, it will be apparent to one skilled in the relevant art(s) how to implement the disclosure in alternative embodiments.