Fan cowl latch concept for fuselage mounted power plant

An aircraft cowl arrangement may comprise a first half, and a second half rotatable between an open position and a closed position, a first seal coupled to the first half, a second seal coupled to the second half, and a latch arrangement for preventing relative movement between the first half and the second half. The latch arrangement may comprise a tie rod comprising a first end coupled to the first half, a second end, and a frame having an opening for receiving the second end of the tie rod, a latch handle rotatably mounted to the frame, and a hook operably coupled to the latch handle, wherein the latch handle is configured to move between a first position wherein the hook is engaged with the second end of the tie rod and a second position wherein the hook is disengaged from the second end of the tie rod.

FIELD

The disclosure generally relates to gas turbine propulsion systems for aircraft, and more particularly to the design of a fan cowl latch for fuselage mounted gas turbine propulsion systems.

BACKGROUND

Modern aircraft may utilize one or more gas turbine engines. A gas turbine engine may be housed in a nacelle. Often, the nacelle includes a fan cowl. The fan cowl may include two doors. Typically, fan cowl door latches join two adjacent fan cowl doors. A fuselage mounted design may have a large gap between the fan cowl doors caused by the pylon structure that has to be bridged by a latching device. The large gap may compromise control of fire seal compression of the nacelle. In addition, the latching device may experience tension and compression due to the latching device bridging the pylon structure.

SUMMARY

A latch arrangement is disclosed, comprising a tie rod comprising a first end and a second end, a frame having an opening for receiving the second end of the tie rod, a latch handle rotatably mounted to the frame, and a hook in operably coupled to the latch handle, wherein the latch handle is configured to move between a first position wherein the hook is engaged with the second end of the tie rod and a second position wherein the hook is disengaged from the second end of the tie rod.

In various embodiments, the opening is at least partially defined by a first contacting surface.

In various embodiments, the second end comprises a second contacting surface having a geometry which is complementary to the first contacting surface.

In various embodiments, the latch arrangement may further comprise a bumper extending from the frame at the opening, wherein the bumper is at least partially defined by the first contacting surface.

In various embodiments, the latch arrangement may further comprise a flange disposed on the tie rod, wherein the flange is at least partially defined by the second contacting surface.

In various embodiments, the bumper and the flange provide a first load path for compressive loads between the tie rod and the frame.

In various embodiments, the latch arrangement may further comprise a pin extending from the second end, wherein the pin and the hook provide a second load path for tensile loads between the tie rod and the hook.

In various embodiments, the latch arrangement may further comprise a plurality of shims disposed between the bumper and the frame.

In various embodiments, the tie rod comprises a first rod, a second rod, and a rotatable member whereby the first rod is coupled to the second rod and wherein rotation of the rotatable member with respect to at least one of the first rod and the second rod at least one of increases and decreases a length of the tie rod.

An aircraft cowl arrangement is disclosed, comprising a first half, and a second half, wherein the first half and the second half are rotatable between an open position and a closed position, a first seal coupled to the first half, a second seal coupled to the second half, and a latch arrangement for preventing relative movement between the first half and the second half, comprising a tie rod comprising a first end and a second end, wherein the first end is coupled to the first half, and a frame having an opening for receiving the second end of the tie rod, a latch handle rotatably mounted to the frame, and a hook operably coupled to the latch handle, wherein the latch handle is configured to move between a first position wherein the hook is engaged with the second end of the tie rod and a second position wherein the hook is disengaged from the second end of the tie rod.

In various embodiments, the opening is at least partially defined by a first contacting surface, wherein the second end comprises a second contacting surface having a geometry which is complementary to the first contacting surface.

In various embodiments, the tie rod extends across a pylon in response to the first half and the second half being in the closed position.

In various embodiments, the first seal and the second seal contact the pylon in response to the first half and the second half being closed.

In various embodiments, the aircraft cowl arrangement may further comprise a bumper extending from the frame at the opening, wherein the bumper is at least partially defined by the first contacting surface.

In various embodiments, the aircraft cowl arrangement may further comprise a flange disposed on the tie rod, wherein the flange is at least partially defined by the second contacting surface, wherein the bumper and the flange provide a first load path for compressive loads between the tie rod and the frame.

In various embodiments, the aircraft cowl arrangement may further comprise a pin extending from the second end, wherein the pin and the hook provide a second load path for tensile loads between the tie rod and the hook.

In various embodiments, the aircraft cowl arrangement may further comprise a plurality of shims disposed between the bumper and the frame.

In various embodiments, the tie rod comprises a first rod, a second rod, and a rotatable member whereby the first rod is coupled to the second rod and wherein rotation of the rotatable member with respect to at least one of the first rod and the second rod at least one of increases and decreases a length of the tie rod.

A method of installing a fan cowl arrangement is disclosed, comprising coupling a first end of a tie rod to a first half of the fan cowl, coupling a frame to a second half of the fan cowl, wherein the frame includes a latch handle rotatably coupled to the frame and a hook operably coupled to the latch handle, coupling a bumper to the frame, and positioning a second end of the tie rod to extend through the bumper.

In various embodiments, the method further comprises positioning one or more shims between the frame and the bumper to adjust a distance between the first half and the second half.

In various embodiments, the method further comprises moving a rotatable member with respect to the tie rod to adjust the distance between the first half and the second half.

The foregoing features, elements, steps, or methods may be combined in various combinations without exclusivity, unless expressly indicated herein otherwise. These features, elements, steps, or methods as well as the operation of the disclosed embodiments will become more apparent in light of the following description and accompanying drawings.

DETAILED DESCRIPTION

Modern aircraft may utilize one or more gas turbine engines. A gas turbine engine may be housed in a nacelle. Often, the nacelle includes a fan cowl. The fan cowl may include two doors. Typically, fan cowl door latches join two adjacent fan cowl doors. A fuselage mounted design may have a large gap between the fan cowl doors caused by the pylon structure that has to be bridged by a latching device. The large gap may compromise control of fire seal compression of the nacelle. In addition, the latching device may experience tension and compression due to the latching device bridging the pylon structure.

A latch arrangement, as disclosed herein, may include a tie rod extending between a first fan cowl half and a second fan cowl half. The fan cowl halves may comprise panels (such as carbon composite panels for example) formed to surround a core engine. The tie rod may operatively couple to a latch hook for securing the tie rod to the second fan cowl half, thereby securing the two fan cowl halves in a closed position and providing a load path for tensile forces between the two fan cowl halves. The tie rod may include a contacting surface for contacting a bumper of the latch housing, providing a load path for compressive load forces between the two fan cowl halves. The latch arrangement may further comprise members for adjusting the distance between the fan cowl halves as desired for properly positioning fire seals against a pylon.

With reference toFIG. 1, a gas turbine engine100of a mixed flow turbofan variety is schematically illustrated, in accordance with various embodiments. The gas turbine engine100generally includes a fan section102and a core engine section104, which includes a compressor section106, a combustor section108and a turbine section110. The fan section102drives air along a bypass flow path B in a bypass duct112defined within inner surface115and an outer casing116of the core engine section104, while the compressor section106drives air along a core flow path C of the core engine section104for compression and communication into the combustor section108and then expansion through the turbine section110. A nacelle114may surround core engine section104and provide a generally aerodynamic profile.

The core engine section104may generally include a low speed spool and a high speed spool mounted for rotation about a central longitudinal axis A. The low speed spool generally includes an inner shaft that interconnects a fan118within the fan section102, a low pressure compressor within the compressor section106and a low pressure turbine within the turbine section110. The inner shaft may be connected to the fan118through a speed change mechanism or gear box to drive the fan118at a lower rotational speed than the rotational speed of the low speed spool. The high speed spool generally includes an outer shaft that interconnects a high pressure compressor within the compressor section106and a high pressure turbine within the turbine section110. A combustor is arranged in the combustor section108between the high pressure compressor and the high pressure turbine. The air passing through the bypass flow path B mixes with the combustion gases exiting the core flow path C in a mixing section122positioned downstream of the core engine section104prior to discharge as a mixed exhaust stream120, which provides the thrust achieved by the gas turbine engine100.

A thrust reverser130is mounted to the aft end of the gas turbine engine100. The thrust reverser130includes a generally annular exhaust duct132, which defines an outer boundary for discharging the mixed exhaust stream120when the thrust reverser130assumes a stowed position (also referred to as a closed position or a retracted position), as illustrated inFIG. 1.

With combined reference toFIG. 2AandFIG. 2B, a fan cowl arrangement200for a gas turbine engine is illustrated according to various embodiments. Fan cowl arrangement200may include a fan cowl204. Fan cowl204may at least partially enclose a gas turbine engine. Fan cowl204may extend along a centerline axis290. In various embodiments, centerline axis290may be co-axial with centerline axis A ofFIG. 1. Fan cowl204may be coupled to a pylon240, which may mount fan cowl204to an aircraft body. Fan cowl204may further be split into a first half210and a second half220. The first half210and the second half220may hinge open at a first side271in order to provide access to an engine. The first half210and the second half220may each comprise a second side272which seal against pylon240. Stated differently, first half210and a second half220may be rotatable between a closed position201, as illustrated inFIG. 2A, and an open position202, as illustrated inFIG. 2B.

First half210may include a seal (also referred to herein as a first seal)212coupled to first half210at second end272. Seal212may contact pylon240in response to first half210being in the closed position201. Second half220may include a seal (also referred to herein as a second seal)222coupled to second half220at second end272. Seal222may contact pylon240in response to second half220being in the closed position201. Seal212may be compressed between first half210and pylon240and seal222may be compressed between second half220and pylon240in response to fan cowl204being in the closed position201.

The distance between second end272of first half210and second end272of second half220may be adjustable via one or more latch arrangements250coupled between first half210and second half220.

With reference toFIG. 3A, a schematic view, looking axially, of a fan cowl arrangement300in a closed position is illustrated, in accordance with various embodiments. In various embodiments, fan cowl arrangement200ofFIG. 2AandFIG. 2Bmay be similar to fan cowl arrangement300. Fan cowl arrangement300may include a first half310and a second half320. Fan cowl arrangement300may include a latch arrangement350. Latch arrangement250may be similar to latch arrangement350, with momentary reference toFIG. 2A. Fan cowl arrangement300may include a first seal coupled to first half310, similar to first seal212ofFIG. 2A, and may include a second seal coupled to second half320, similar to second seal222ofFIG. 2A. However, these seals are omitted for clarity purposes inFIG. 3AandFIG. 3B.

Latch arrangement350may comprise a rod (also referred to herein as a tie rod)360comprising a first end362and a second end364. Latch arrangement350may include a frame370having an opening395for receiving the second end364of tie rod360. Latch arrangement350may include a latch handle376operably coupled to a hook375. Latch handle376may be rotatably mounted to the frame370and configured to move between a first position (also referred to herein as a closed position and as illustrated inFIG. 3A) wherein the hook375is engaged with the second end364of the tie rod360and a second position (also referred to herein as an open position and as illustrated inFIG. 3B) wherein the hook375is disengaged from the second end364of the tie rod360.

In various embodiments, a pin368may extend from second end364of tie rod360. In the first position, as illustrated inFIG. 3A, hook375may engage pin368, whereby tie rod360may be secured to second half320. In the second position, as illustrated inFIG. 3B, hook375may be disengaged from pin368, whereby tie rod360is decoupled from second half320. Hook375may be operatively coupled to latch handle376via any suitable means known by a person having ordinary skill in the art whereby hook375releases pin368in response to latch handle376being moved to the open position as illustrated inFIG. 3B.

In various embodiments, tie rod360may include a contacting surface (also referred to herein as a second contacting surface)366defined by a flange367projecting from the outer surface361of tie rod360. In various embodiments, tie rod360may comprise a cylindrical geometry, wherein the flange367comprises an annulus disposed on the outer surface361of tie rod360. In various embodiments, contacting surface366may comprise a conical geometry truncated by tie rod360, as illustrated inFIG. 4A. In various embodiments, contacting surface366′ may comprise a hemispherical geometry truncated by tie rod360′, as illustrated inFIG. 4B.

In various embodiments, frame370may include a bumper380extending from frame370at opening395. Bumper380may include a contacting surface (also referred to herein as a first contacting surface)382. In this regard, opening395may be at least partially defined by contacting surface382. The geometry of contacting surface382may be complementary to the geometry of contacting surface366. For example, if contacting surface366is a conical geometry, then contacting surface382may be a similar conical geometry against which contacting surface366may evenly contact. Bumper380may comprise an annulus configured to receive second end364of tie rod360. In this regard, contacting surface382may comprise an annulus.

In various embodiments, latch arrangement350may include a plurality of shims386disposed between frame370and bumper380. With combined reference toFIG. 3AandFIG. 2A, the number of shims386may be chosen such that seal212and seal222are properly seated against pylon240. For example, the number of shims386may be chosen such that, in closed position201, seal212and seal222are compressed against pylon240and contacting surface366is compressed against contacting surface382. In this manner, plurality of shims386may effectively adjust the distance between second ends272of first half210and second half220.

In various embodiments, the number of shims386may be chosen such that contacting surface366is in contact with contacting surface382in response to latch handle376being in the closed position. The number of shims386may be chosen such that contacting surface366is compressed against contacting surface382in response to latch handle376being in the closed position.

In various embodiments, latch arrangement350may be suitable for handling both compressive loads and tensile loads between first half310and second half320. Compressive loads may be transferred between bumper380and flange367. In this regard, a first load path may be formed between bumper380and flange367of tie rod360for transferring compressive loads. Tensile loads may be transferred between hook375and pin368. In this regard, a second load path may be formed between hook375and pin368for transferring tensile loads.

With reference toFIG. 5A, a cross-section view of latch arrangement350, looking in the radial direction, is illustrated, in accordance with various embodiments. Bumper380may be coupled to frame370via one or more fasteners502. Fastener502may be a bolt, for example. Shims386may be compressed between bumper380and frame370via fastener502. In this regard, fastener502may extend between bumper380and frame370.

In various embodiments, second end364of tie rod360may comprise a U-shaped end having pin368extending between the end. Stated differently, second end364may comprise a first lobe504and a second lobe506with pin368extending between first lobe504and second lobe506.

With reference toFIG. 5B, a cross-section view, perpendicular to the cross-section view ofFIG. 5A, of latch arrangement350is illustrated, in accordance with various embodiments. In various embodiments, second half320may comprise an outer surface522and an inner surface524. Outer surface522may be an aerodynamic surface. In various embodiments, latch handle376may be flush with outer surface522. Inner surface524may be a radially inner surface. Frame370may be coupled to inner surface524of second half220.

With reference toFIG. 6, a schematic view, looking axially, of a fan cowl arrangement600in a closed position is illustrated, in accordance with various embodiments. In various embodiments, fan cowl arrangement200ofFIG. 2Amay be similar to fan cowl arrangement600. Fan cowl arrangement600may be similar to fan cowl arrangement300ofFIG. 3A, except that, instead of having a plurality of shims, fan cowl arrangement600includes a turn-buckle style tie rod for adjusting the distance between a first half610of a fan cowl and a second half620of the fan cowl. In this regard, fan cowl arrangement600may include a latch arrangement650having a turn-buckle tie rod660. Tie rod660may include a first rod662and a second rod664. First rod662and/or second rod664may be threadingly coupled to a rotatable member666. Rotation of rotatable member666with respect to at least one of first rod662and a second rod664in a first direction may increase the length of tie rod660. Rotation of rotatable member666with respect to at least one of first rod662and a second rod664in a second direction may decrease the length of tie rod660. In this manner, tie rod660may be adjusted for proper fitment for fan cowl arrangement600. In this regard, bumper380may be attached directly to frame370. In various embodiments, bumper380and frame370may be two separate parts. In various embodiments, bumper380and frame370may be made from a single piece of material.

With reference toFIG. 7, a method700for installing a fan cowl arrangement is illustrated, in accordance with various embodiments. Method700includes coupling a first end of a tie rod to a first fan cowl half (step710). Method700includes coupling a latch frame to a second fan cowl half (step720). Method700includes coupling a bumper to the frame (step730). Method700includes positioning a second end of the tie rod to extend through the bumper (step740). Method700may include positioning one or more shims between the frame and the bumper (step750). Alternatively, method700may include moving a rotatable member with respect to the tie rod (step752).

With combined reference toFIG. 3AandFIG. 7, step710may include coupling first end362of tie rod360to first half310. First end362may be coupled to first half310via an attachment feature369. In various embodiments, attachment feature may comprise a spherical bearing. In this regard, first end362may comprise a spherical rod end, for example. In this regard, attachment feature may accommodate axial movement of first half310with respect to second half320via attachment feature369. Step720may include coupling frame370to second half320. Frame370may be coupled to second half320via one or more fasteners, such as a bolt or rivet, among others. Step730may include coupling bumper380to frame370. Step730may include inserting one or more fasteners502through bumper380and frame370to secure bumper380to frame370. Step740may include positioning second end364to extend through bumper380. Second end364may extend through bumper380to secure pin368of second end364to hook375. Latch handle376may be rotated to the closed position to secure pin368to hook375.

In various embodiments, step750may include positioning one or more shims386between frame370and bumper380to adjust a distance (e.g., the circumferential distance (i.e., the direction along the Y-axis ofFIG. 3A)) between second end372of first half310and second end373of second half320, with momentary reference toFIG. 3A. For example, adding less shims386will decrease the distance between second end372and second end373. In contrast, positioning more shims386will increase the distance between second end372and second end373. In this manner, the positioning of seal212and seal222with respect to pylon240may be adjusted, with momentary reference toFIG. 2A.

In various embodiments, with combined reference toFIG. 6andFIG. 7, step752may include moving rotatable member666with respect to tie rod660to adjust the distance between second end672of first half610and second end673of second half620. For example, decreasing the length of tie rod660will decrease the distance between second end672and second end673and increasing the length of tie rod660will increase the distance between second end672and second end673. In this manner, the positioning of seal212and seal222with respect to pylon240may be adjusted, with momentary reference toFIG. 2A.

In various embodiments, bumper380may be made from a metal, such as steel, among others. In various embodiments, shims386may be made from a metal, such as steel, among others. In various embodiments, tie rod360may be made from a metal, such as steel, among others.