Abstract:
A system for a thrust reverser of an aircraft includes a primary sleeve and a secondary sleeve having cascades. The secondary sleeve is coupled to a set of blocker doors. The sliding motions of the primary sleeve and the secondary sleeve are not directly coupled when each moves between its stowed and deployed positions. The sliding motion of the primary sleeve may begin at a different time and continue at a different rate from the sliding motion of the secondary sleeve.

Description:
BACKGROUND 
       [0001]    Within a turbo fan engine that utilizes a cascade type thrust reverser, there are typically a plurality of blocker doors that deploy in order to redirect engine bypass air thru a set of cascades that turn the airflow out and forward in order to reverse the direction of the thrust of the engine. This may be done to slow an aircraft after landing. Referring to  FIG. 1A , a system  100  is shown. The system  100  includes a sleeve  102  that is translated or moved in, e.g., an aft direction in order to expose cascades  104  as part of the deployment of the thrust reverser. Similarly, in order to place the thrust reverser in a stowed state (e.g., during flight) the sleeve  102  is translated or moved in, e.g., a forward (FWD) direction, such that the sleeve  102  may contact or abut a thrust reverser fixed structure  106 . When in the stowed state, the cascades  104  are not exposed.  FIG. 3  illustrates the system  100  in the stowed state. An entirety of a nacelle is shown in  FIG. 3 , whereas a portion (e.g., a half) of the nacelle is shown in  FIG. 1A . 
         [0002]    The blocker doors described above are typically pivotally attached to the sleeve  102  within the thrust reverser.  FIG. 1B  illustrates a blocker door  108  of the system  100  hinged to the sleeve  102  near a point  110 . Additionally, the door  108  is attached to the inner fixed structure  114  of the thrust reverser via a drag link  112  that retains the door  108  in position during normal flight as well as aids in the deployment of the door  108  during thrust reverse mode. During flight, the door  108  forms, in part, the outer surface of a bypass duct. The drag link  112  crosses this bypass duct in attaching to the inner fixed structure. 
         [0003]    The drag link  112  lies within the engine airflow and generates drag losses on the engine, resulting in degraded efficiencies. Any steps and gaps around the blocker door  108  generate aerodynamic disturbances that reduce overall efficiency. 
         [0004]    Moreover, in conventional thrust reverser systems the actuation mechanism used to drive the sleeve  102  is the same mechanism that is used to drive the blocker door  108 . Accordingly, the sleeve  102  and blocker door  108  are operated at the same speed and over commonly-defined distances (also referred to as strokes). 
       BRIEF SUMMARY 
       [0005]    The following presents a simplified summary in order to provide a basic understanding of some aspects of the disclosure. The summary is not an extensive overview of the disclosure. It is neither intended to identify key or critical elements of the disclosure nor to delineate the scope of the disclosure. The following summary merely presents some concepts of the disclosure in a simplified form as a prelude to the description below. 
         [0006]    Aspects of the disclosure are directed to a thrust reverser of an aircraft comprising: a primary sleeve, and a secondary sleeve coupled to a blocker door, wherein a stroke associated with the primary sleeve is different from a stroke associated with the secondary sleeve. In some embodiments, the secondary sleeve is coupled to a first link, and the first link is coupled to a crank, and the crank is coupled to a second link, and the second link is coupled to the blocker door. In some embodiments, the first link is configured to be oriented in a substantially axial direction relative to an axis of the thrust reverser when the thrust reverser is fully deployed. In some embodiments, the blocker door is configured to provide load from the blocker door through the second link and the crank to a fixed structure of the aircraft. In some embodiments, the thrust reverser further comprises a ring configured to couple to the blocker door. In some embodiments, the blocker door is configured to be stowed above a skin associated with at least one of the primary sleeve and a duct when the thrust reverser is stowed. In some embodiments, the primary sleeve and the secondary sleeve are configured to be driven via independent actuation mechanisms. 
         [0007]    Aspects of the disclosure are directed to a thrust reverser of an aircraft comprising: a movable primary sleeve with an exterior surface exposed to the exterior free air stream around the thrust reverser during flight, the primary sleeve movable between a stowed position and a deployed position corresponding to reverse thrust operation, a movable secondary sleeve that includes a cascade for redirecting air from a fan duct during reverse thrust operation, the secondary sleeve movable between a stowed position and a deployed position corresponding to reverse thrust operation, and wherein the primary sleeve covers the cascade when the primary sleeve is in its stowed position, and the cascade is exposed to the exterior free air stream when the primary sleeve is in its deployed position. In some embodiments, the thrust reverser further comprises: a blocker door coupled to the secondary sleeve, the blocker door movable between a stowed position and a deployed position corresponding to reverse thrust operation, and wherein the blocker door is driven from its stowed position to its deployed position when the secondary sleeve moves from its stowed position to its deployed position. In some embodiments, the primary sleeve further comprises an interior skin and an exterior skin, the blocker door being fully positioned between the interior skin and the exterior skin when the blocker door is in its stowed position. In some embodiments, the thrust reverser further comprises: a first sliding mechanism coupled with the primary sleeve such that the primary sleeve is movable by sliding relating to a fixed structure of the thrust reverser along a sliding axis defined by the first sliding mechanism, and a second sliding mechanism coupled with the secondary sleeve such that the secondary sleeve is movable by sliding relating to a fixed structure of the thrust reverser along a sliding axis defined by the second sliding mechanism. 
         [0008]    Aspects of the disclosure are directed to a thrust reverser of an aircraft comprising: a movable primary sleeve with an exterior surface exposed to the exterior free air stream around the thrust reverser during flight, the primary sleeve movable between a stowed position and a deployed position corresponding to reverse thrust operation, a movable secondary sleeve, the secondary sleeve movable between a stowed position and a deployed position corresponding to reverse thrust operation, a blocker door coupled to the secondary sleeve and movable between a stowed position and a deployed position corresponding to reverse thrust operation wherein the blocker door redirects air through a cascade, wherein when the secondary sleeve moved from its stowed position to its deployed position it drives the blocker door from its stowed position to its deployed position. In some embodiments, the cascade is mounted on and moves with the secondary sleeve. In some embodiments, at least a portion of the cascade radially overlaps a fan case of a turbofan engine, such as when the secondary sleeve is in a stowed position. In some embodiments, the blocker door is hidden from exposure to the air stream in a fan duct when the blocker door is in its stowed position. 
         [0009]    Aspects of the disclosure are directed to a system for a thrust reverser of an aircraft comprising: fixed structure of the aircraft, and a blocker door pivotally supported by the fixed structure. In some embodiments, the system further comprises a primary sleeve, and a secondary sleeve coupled to the blocker door, wherein a stroke associated with the primary sleeve is different from a stroke associated with the secondary sleeve. In some embodiments, the primary sleeve and the secondary sleeve are configured to be driven via independent actuation mechanisms. In some embodiments, the system further comprises: a first link coupled to the secondary sleeve, a crank coupled to the first link, and a second link coupled to the crank, wherein the second link is coupled to the blocker door. In some embodiments, the first link is configured to be oriented in a substantially axial direction relative to an axis of the thrust reverser when the thrust reverser is fully deployed. In some embodiments, the blocker door is configured to provide load from the blocker door through the second link and the crank to the fixed structure. In some embodiments, the system further comprises a ring located aft of the fixed structure coupled to the blocker door. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0010]    The present disclosure is illustrated by way of example and not limited in the accompanying figures in which like reference numerals indicate similar elements. 
           [0011]      FIG. 1A  schematically illustrates a thrust reverser system incorporating a translating sleeve in accordance with the prior art. 
           [0012]      FIG. 1B  schematically illustrates a drag link of the system of  FIG. 1A  in accordance with the prior art. 
           [0013]      FIGS. 2A-2C  schematically illustrate a thrust reverser system in accordance with aspects of the disclosure. 
           [0014]      FIG. 3  illustrates a nacelle incorporating a thrust reverser. 
           [0015]      FIGS. 4A-4B  illustrate the thrust reverser of  FIGS. 2A-2C  in a deployed condition. 
           [0016]      FIGS. 5A-5B  illustrate a thrust reverser in accordance with aspects of the disclosure. 
       
    
    
     DETAILED DESCRIPTION 
       [0017]    It is noted that various connections are set forth between elements in the following description and in the drawings (the contents of which are included in this disclosure by way of reference). It is noted that these connections are general and, unless specified otherwise, may be direct or indirect and that this specification is not intended to be limiting in this respect. A coupling between two or more entities may refer to a direct connection or an indirect connection. An indirect connection may incorporate one or more intervening entities. 
         [0018]    In accordance with various aspects of the disclosure, apparatuses, systems and methods are described for making and using a translating cascade thrust reverser. In some embodiments, a translating cascade/secondary sleeve and a blocker door/primary sleeve can be operated via separate actuation or drive mechanisms, potentially in accordance with timing criteria (e.g., mechanically-based timing criteria). 
         [0019]    Referring to  FIGS. 2A-2C , a system  200  is shown. The system  200  includes a number of components/devices that are described further below. The views shown in  FIGS. 2A-2C  may represent a cross-section of a thrust reverser or nacelle, such as about the line A-A′ of  FIG. 1A . 
         [0020]    The system  200  includes a crank  222 , which may be referred to as (or correspond to) a main crank. The crank  222  is coupled to a driver link  224 . The driver link  224  is coupled to a translating cascade  226 , where the translating cascade  226  may be referred to as (or correspond to) a secondary sleeve. The translating cascade  226  may be coupled to one or more sliders (not shown) to support movement or translation of the translating cascade  226 . 
         [0021]    The crank  222  is coupled to a blocker link  228 . The blocker link  228  is coupled to a blocker door  208 . The blocker door  208  is coupled to a ring  230 , which may be referred to as (or correspond to) an aft ring. 
         [0022]    The blocker door  208  is similar to the blocker door  108  of the system  100 . The blocker door  208  may be hidden in the sense that the majority or the entirety of its structure is not exposed to any fan bypass air flow in the fan duct during normal operation. By hiding the door  208 , thrust reverser performance may be maximized/enhanced by allowing for a very smooth duct surface (free from or with significantly reduced steps and gaps) on skin  236 , reducing the drag. In addition, because the blocker door geometry is no longer constrained or driven by the need to create an aerodynamically smooth surface when the door is stowed, the shape, geometry, or configuration of the door  208  may be selected to obtain improved or optimal thrust reverser performance. 
         [0023]    The crank  222  is coupled to a structure  232  of the aircraft at a (pivot) point  233 . The structure  232  may represent fixed structure of an aircraft and a direct load path into a torque box (not shown). 
         [0024]    As shown in  FIG. 2A , a sleeve  202  (which is similar to the sleeve  102  of the system  100 ) and a duct  234  are included as part of the system  200 . The sleeve  202  may be referred to as a primary sleeve herein. The door  208  may reside above a skin  236  of the sleeve  202  and/or duct  234  when the thrust reverser is operated in the stowed state. 
         [0025]    The system  200  may include a number of four-bar mechanisms. A first four-bar mechanism may include the crank  222 , the driver link  224 , the translating cascade  226 , and the structure  232 . A second four-bar mechanism may include the crank  222 , the blocker link  228 , the blocker door  208 , and the structure  232 . 
         [0026]    Superimposed in  FIG. 2A  is an illustration of a first stroke  202 ′ associated with the sleeve  202  relative to a second stroke  226 ′ associated with the translating cascade  226 . As used herein a stroke refers to the potential distance that a respective element may traverse. As shown in  FIG. 2A , the first stroke  202 ′ is different from the second stroke  226 ′. 
         [0027]    In the progression from  FIG. 2A  to  FIG. 2B  and from  FIG. 2B  to  FIG. 2C , the blocker door  208  transitions from a stowed state ( FIG. 2A ), to a state between stowed and deployed (e.g., 50% deployed) ( FIG. 2B ), to a deployed state ( FIG. 2C ).  FIG. 2B  may represent. 
         [0028]    The greatest loads are generally experienced by the system  200  when the thrust reverser is fully deployed (e.g.,  FIG. 2C ). In  FIG. 2C , the driver link  224  is oriented in a substantially axial direction relative to an axis or center-line of the thrust reverser. Accordingly, any bending in the translating cascade  226  is minimized/reduced because the load introduced by the driver link  224  to the cascade  226  is in line with the cascade axial direction and only slightly offset. In addition, load from the blocker door  208  is provided through the blocker link  228  and the crank  222  to the structure  232 , which is a structurally efficient load path and also minimizes bending because the blocker link  228  is in line and parallel with the load path through the crank  222 . 
         [0029]    As shown in  FIGS. 2A-2C , the door  208  is pivotally supported with respect to the fixed structure (e.g., structure  230  and  232 ), as opposed to being pivotally supported by the sleeve  202 . 
         [0030]      FIGS. 4A and 4B  illustrate the thrust reverser from  FIGS. 2A through 2C  in the deployed condition, and include a view of the sliding mechanisms for the sleeve  202  and the translating cascade/secondary sleeve  226 . Because they move at different rates, times and have different strokes, the sliding mechanisms for each are separate. A sliding mechanism  402  serves the sleeve  202 . Sliding mechanism  402  includes a portion that is mounted to sleeve  202  and a portion that is mounted to a hinge beam  404 , and the two portions are configured to slide relative to one another. Likewise, sliding mechanism  426  serves the secondary sleeve  226 , and includes a portion that is mounted to secondary sleeve  226  and a portion that is mounted to the hinge beam  404 , and the two portions are configured to slide relative to one another. This allows the primary sleeve  202  and the secondary sleeve  226  to move independently of one another. Those of ordinary skill in this art will also recognize that similar sliding mechanisms may be included at the six o&#39;clock position of the primary sleeve  202  and the secondary sleeve  226  in some embodiments. 
         [0031]      FIGS. 5A-5B  schematically illustrate cross-sectional views of a cascade and propulsion system  500  similar to the arrangements described above in connection with  FIGS. 2A-2C and 4A-4C . In particular,  FIGS. 5A-5B  illustrate that when a thrust reverser is in a stowed condition/state cascades  526  partially or completely overlap (in the radial direction of the system  500 ) the fan case, and in the deployed condition/state there is no overlap, the forward edge of the cascade assembly  526  is about in-line with the trailing edge of the fan case, and the cascades  526  are exposed. 
         [0032]    The primary sleeve  202  and the secondary sleeve  226  may be actuated in conventional and known manners, as will be recognized by those of ordinary skill in this art. A pneumatic, hydraulic or lead screw actuator may be positioned between each sleeve and any fixed structure of the thrust reverser in order to control the deployment of each sleeve. It may also be possible to use a single actuator to deploy both sleeves, with special arrangements made so that the sleeves can begin their deployment at different times and deploy at different rates and with different strokes. 
         [0033]    While some of the examples were described above in connection with a translating cascade reverser, one skilled in the art would appreciate that aspects of the disclosure may be applied in connection with any type of reverser, such as a secondary sleeve reverser and/or conventional reversers including those with fixed nozzles/trailing edges. Further, the mechanism can be tailored for transient and deployed area match as may be required for a particular application. 
         [0034]    Technical effects and benefits of the disclosure include obtaining a maximum/increased efficiency in terms of engine operation/output by minimizing/reducing drag losses. Additionally, the size/profile of one or more components/devices may be minimized/reduced, allowing for shorter lines of travel and better/different packaging options. Configuring the cascade so that it overlies the fan case when stowed should allow for the thrust reverser to be shorter than would otherwise be the case. Separating a translating cascade/secondary sleeve stroke from a primary sleeve stroke facilitates the design feature of positioning the cascade over the fan case in its stowed position. 
         [0035]    Aspects of the disclosure have been described in terms of illustrative embodiments thereof. Numerous other embodiments, modifications, and variations within the scope and spirit of the appended claims will occur to persons of ordinary skill in the art from a review of this disclosure. For example, one of ordinary skill in the art will appreciate that the steps described in conjunction with the illustrative figures may be performed in other than the recited order, and that one or more steps illustrated may be optional in accordance with aspects of the disclosure.