Nacelle inner flow structure leading edge latching system

A latch assembly for securing a nacelle portion of a gas turbine engine includes an engine case structure that includes a core compartment. An inner flow structure has closed and opened positions with respect to the engine case structure. The inner flow structure encloses the core compartment in the closed position and provides access to the core compartment in the opened position. A bypass flowpath is provided by a portion of the engine case structure and the inner flow structure. A seal is engaged with the engine case structure and the inner flow structure in the closed position. A latch has a latched position in which radial movement of the inner flow structure relative to the engine case structure is impeded and maintained in the closed position and an unlatched position in which the inner flow structure is permitted to move radially outward to the opened position.

BACKGROUND

This disclosure relates to a nacelle for a gas turbine engine. More particularly, the disclosure relates to a latching system configured to ensure that the latch is able to disengage and release a portion of a nacelle.

One type of gas turbine engine includes a core engine that drives a fan arranged in a bypass flowpath. The bypass flowpath is provided between core and fan nacelles, the core nacelle surrounds the core engine. One example gas turbine engine includes a flow structure that provides inner and outer flow structures that define the bypass flowpath. The flow structure provides portions of the fan and core nacelles along one axial portion of the engine.

The core nacelle encloses a core compartment that houses pressurized conduits, such as compressed air ducts. While the bypass flow pressure in the bypass flowpath aids in maintaining the inner flow structure in a closed and sealed position around the core flowpath, if a high pressure conduit bursts, the pressure within the core compartment may increase and separate a leading edge of the inner flow structure from its mating structure. In this condition, bypass flow may leak past the inner flow structure into the core compartment, which may destroy and dislodge portions of the core and fan nacelles.

To this end, latching assemblies have been proposed, which maintain the leading edge of the inner flow structure in a fully closed position. The latching assembly may be rather complex and may be susceptible to becoming stuck, which requires surrounding structure to be disassembled and removed to gain access to the stuck latch.

SUMMARY

In one exemplary embodiment, a latch assembly for securing a nacelle portion of a gas turbine engine includes an engine case structure that includes a core compartment. An inner flow structure has closed and opened positions with respect to the engine case structure. The inner flow structure encloses the core compartment in the closed position and provides access to the core compartment in the opened position. A bypass flowpath is provided by a portion of the engine case structure and the inner flow structure. A seal is engaged with the engine case structure and the inner flow structure in the closed position. A latch has a latched position in which radial movement of the inner flow structure relative to the engine case structure is impeded and maintained in the closed position and an unlatched position in which the inner flow structure is permitted to move radially outward to the opened position.

In a further embodiment of the above, first and second reaction load brackets are affixed relative to the engine case structure and the inner flow structure. One of the first and second reaction load brackets pivotally supports the latch and the other of the first and second reaction load brackets includes a tab that cooperates with the latch in the latched position.

In a further embodiment of any of the above, a cable is operatively connected to the latch and is configured to rotate the latch about the pivot.

In a further embodiment of any of the above, a bifurcation is arranged in the bypass flowpath. The cable passes through the bifurcation.

In a further embodiment of any of the above, first and second drive elements are respectively connected to the latch and cable and configured to transmit input from the cable to the latch.

In a further embodiment of any of the above, the first and second drive elements are gears.

In a further embodiment of any of the above, a handle is connected to the cable. The handle is configured to actuate the latch through the cable.

In a further embodiment of any of the above, a coupling operatively connects the handle to a pair of cables. Each cable unlatching a side that has the first and second nacelle flow structures.

In a further embodiment of any of the above, the inner flow structure is movable relative to the engine case structure about a hinge. The inner flow structure provides radially inner and outer flow path surfaces defining the bypass flowpath.

In a further embodiment of any of the above, the inner flow structure provides a portion of a core nacelle that encloses the core compartment about a core engine and comprises a compressed air duct arranged in the core compartment.

In a further embodiment of any of the above, a fan case and flow exit guide vanes are interconnected between the fan case and the engine case structure. The latch is arranged aft of the flow exit guide vanes. The seal is arranged at a leading edge of the inner flow structure.

In a further embodiment of any of the above, a release member is operatively coupled to the latch to override a conventional latch releasing device.

In a further embodiment of any of the above, a tool is removably received by the release member during an emergency latch releasing procedure.

In a further embodiment of any of the above, there is a thrust reverser. The thrust reverser is in an open position to receive the tool in the bypass flowpath.

In another exemplary embodiment, a method of opening a nacelle flow structure includes the steps of moving a latch from a latched position to an unlatched position and latching an inner flow structure relative to an engine case structure in response to the latch moving step.

In a further embodiment of any of the above, the method includes the step of operating a handle operatively connected to the latch. The latch moving step is performed in response to the handle operating step.

In a further embodiment of any of the above, the method includes the step of operating a release member with a tool subsequent to a failed attempt of a conventional latch releasing procedure.

In a further embodiment of any of the above, the conventional latch releasing procedure includes operating a handle operatively connected to the latch. The latch moving step is performed in response to the handle operating step.

In a further embodiment of any of the above, the method includes the step of actuating a thrust reverser to expose a bypass flowpath and inserting the tool into the bypass flowpath to engage the release member.

DETAILED DESCRIPTION

An example gas turbine engine10is schematically illustrated inFIG. 1. The engine10includes a core engine12receiving a core flow C at an inlet14. The core flow C flows through the core engine12and is expelled through an exhaust outlet16surrounding a tail cone20.

The core engine12drives a fan18arranged in a bypass flowpath23. A fan case22surrounds the fan18and provides structure for securing the engine10to a pylon38(FIG. 2). The fan case22is housed within a fan nacelle19. Multiple circumferentially spaced flow exit guide vanes24may extend radially between the fan case22and the core engine12aft of the fan18. In one example, the flow exit guide vanes24are hollow and may accommodate wires or fluid conduits.

A core nacelle21surrounds the core engine12and provides a core compartment30. Various components may be provided in the core compartment30, such as fluid conduits, for example, a compressed air duct32. The compressed air duct32is under high pressure and may supply compressed air from a low or high pressure compressor stage to a high pressure turbine stage for cooling, for example.

Upper and lower bifurcations26,27may extend radially between the fan and core nacelles19,21in locations opposite one another to accommodate wires, fluid conduit or other components.

The bypass flowpath23is provided by inner and outer flow structures50,51, which provide portions of the fan and core nacelles19,21along an axial portion of the engine10. A thrust reverser28is arranged outwardly of the outer flow structures51in the fan nacelle19. The inner flow structure50is secured about the core compartment30with a latch assembly36, which may be actuated by a handle34mounted outside the fan nacelle19, for example. A cable70(FIGS. 6 and 7) may be routed from the handle34through one of the upper and lower bifurcations26,27to the latch assembly36, for example. Additionally, latches may also be used and located as desired. The handle34provides a conventional latch releasing device for a conventional latch releasing procedure.

Referring toFIG. 2, the inner and outer flow structures50,51, which are integral with one another, are supported relative to the pylon38by hinges40. Upper and lower bumpers42,44support the inner flow structure50relative to the upper and lower bifurcations26,27in a desired position. During normal operation, as illustrated inFIG. 2, bypass pressure BP within the bypass flowpath23exerts a force on the inner flow structure50that maintains desired engagement with the upper and lower bumpers42,44. Referring toFIG. 3, an undesirably high core pressure CP may result from a ruptured pressurized fluid conduit, such as the compressed air duct32. As a result of such a high pressure core compartment event, the inner flow structure50may become deformed, as illustrated on the left half ofFIG. 3. During the event, either or both left and right side flow structures may deflect without the disclosed latch.

Referring toFIGS. 4A and 4B, the inner flow structure50supports a seal54at a leading edge52. The seal54engages a flange48of an engine case structure46with the inner flow structure50being flush with the structure46during normal operation such that the structure46and inner flow structure50provide uninterrupted first and second nacelle flow structures. During an event in which an undesired core pressure CP is generated within the core compartment30, the inner flow structure50and seal54may be forced radially outward and out of engagement with the flange48, which permits bypass flow B in a bypass flowpath23to enter the core compartment30. Such a condition may result in damage to the core nacelle21.

Referring toFIGS. 5A and 5B, the latch assembly36is arranged near the leading edge52prevent deflection of the inner flow structure50and maintain the seal54in engagement with the flange48even if undesired core pressure CP exists. In one example, a first load reaction bracket56is supported by the structure46. A second load reaction bracket58is mounted to the inner flow structure50. The first load reaction bracket56includes a tab60that cooperates with a latch62pivotally mounted to the second load reaction bracket58to maintain the position of the inner flow structure50when latched, shown inFIG. 5A. In one example, a first drive element64is connected to the latch62. A second drive element66cooperates with the first drive element64and is operably connected to the handle34(FIG. 1) for actuation of the latch assembly36. In one example, the first and second drive elements66,68are gears that transmit input to the latch62.FIG. 5Billustrates the latch62in an open position in which the latch62is disengaged from the tab60. Latch assembly36may use a different configuration of drive elements, if desired.

FIGS. 6 and 7illustrate one example routing of cables70interconnecting the handle34to the latch assembly36. The cable70rotates the latch62about its pivot. One cable70may be provided for each half of the inner flow structure50provided on either side of the engine10, illustrated inFIG. 2. The handle34may be positioned at the lower bifurcation27. A coupling68mechanically interconnects the handle34to cables70, which are arranged within a cavity72of the lower bifurcation27.

Alternatively or additionally, the latch36may be located in the aft section of the core nacelle21. The latches136A-C may also be used to secure the left and right halves of the flow structures to one another, as best shown inFIGS. 1 and 2.

In the event that the latch assembly36becomes stuck or a cable70breaks, a release member80may cooperate with the latch assembly36to release the latch62and override the conventional latch releasing procedure and provide an emergency release of the latch62. In one example, the thrust reverser28is actuated to expose the bypass flowpath23and the release member80. With the thrust reverser28actuated, the blocker doors76are disposed within the bypass flowpath23and the cascade assembly74is exposed. A tool78may be passed through the cascade assembly74into the bypass flowpath23to engage the release member80. As illustrated inFIG. 8B, an end84of the tool78may be received in a head82of the release member80. The release member80may cooperate with one or more of the first and second drive elements64,66to rotate the latch62out of engagement with the tab60. The illustration of the release member80is schematic.