Abstract:
A nacelle structure for a gas turbine engine includes an outer nacelle surrounding a fan section and defining an outer boundary of a bypass flow passage and an inner nacelle surrounding a core engine section and defining an inner boundary of the bypass flow passage. A panel of the inner nacelle is moveable between an open position providing access to the core engine section and a closed position. A lock is supported within the inner nacelle proximate the panel. The lock includes an electric actuator for moving a locking pin between a locked position and an unlocked position. The lock prevents opening and limits deflection of the panel when in the locked position.

Description:
BACKGROUND 
       [0001]    A gas turbine engine typically includes a fan section, and a core engine including a compressor section, a combustor section and a turbine section. Air entering the compressor section is compressed and delivered into the combustion section where it is mixed with fuel and ignited to generate a high-speed exhaust gas flow. The high-speed exhaust gas flow expands through the turbine section to drive the compressor and the fan section. 
         [0002]    A nacelle structure is provided about the fan section and core engine section. The core engine section of the nacelle includes a forward edge exposed to bypass air flow. Increased pressures within the core engine nacelle can deflect openable panels outward such that bypass airflow is drawn under gaps in the panels. Bypass airflow on core nacelle panels exert loads potentially beyond those contemplated by the latching system. 
         [0003]    Furthermore, large bypass engines can have relatively low pressure in the bypass duct, which in turn reduces forces pushing the core engine nacelle towards the engine. The reduced pressure differentials between the core engine compartment and the bypass duct can contribute to a larger outward deflection or formation of gaps in the core engine nacelle. Large fan bypass ratios may reduce pressure in the bypass duct that in turn reduces the pressure aiding in holding the core engine nacelle in place. The reduced differential pressures across the core engine nacelle can generate a bias toward outward deflections of core engine nacelle panels compared with previous gas turbine engine configurations. 
         [0004]    Additional mechanically actuated locks can be utilized to prevent the formation of gaps. Mechanically actuated locking devices use mechanical linkages that run from the core engine to the outer fan case and nacelle structure. Mechanical linkages extending between the core engine and the fan case add weight and complexity. 
         [0005]    Accordingly, it is desirable to design and develop locking devices for the core engine nacelle section that reduce complexity while maintaining panel position during engine operation. 
       SUMMARY 
       [0006]    A nacelle structure for a gas turbine engine according to an exemplary embodiment of this disclosure, among other possible things includes an outer nacelle surrounding a fan section and defining an outer boundary of a bypass flow passage, an inner nacelle surrounding a core engine section and defining an inner boundary of the bypass flow passage, a panel of the inner nacelle moveable between an open position providing access to the core engine section and a closed position, and a lock supported within the inner nacelle proximate the panel, the lock including an electric actuator for moving a locking pin between a locked position preventing opening of the panel and an unlocked position. 
         [0007]    In a further embodiment of the foregoing nacelle structure, includes a blocker mounted to a fixed structure of the core engine section blocking movement of the pin when the lock is in the locked position. 
         [0008]    In a further embodiment of any of the foregoing nacelle structures, the electric actuator comprises a solenoid for moving the pin between the locked and unlocked positions. 
         [0009]    In a further embodiment of any of the foregoing nacelle structures, the electric actuator comprises an electric motor for moving the pin between the locked and unlocked positions. 
         [0010]    In a further embodiment of any of the foregoing nacelle structures, includes a wire harness for communicating control signals to the lock. The wire harness extends through a structure extending radially between the inner nacelle and the outer nacelle. 
         [0011]    In a further embodiment of any of the foregoing nacelle structures, includes a switch mounted remote of the lock within the outer nacelle. 
         [0012]    In a further embodiment of any of the foregoing nacelle structures, the switch prevents closure of a cowling when in an unlocked position. 
         [0013]    In a further embodiment of any of the foregoing nacelle structures, includes a manual override for moving the locking pin from a locked position to an unlocked position without operating the electric actuator. 
         [0014]    A gas turbine engine according to an exemplary embodiment of this disclosure, among other possible things includes a fan including a plurality of fan blades rotatable about an axis. A core engine section includes a compressor section, a combustor in fluid communication with the compressor section, and a turbine section in fluid communication with the combustor. A geared architecture is driven by the turbine section for rotating the fan about the axis. An outer nacelle surrounds a fan section and defines an outer boundary of a bypass flow passage. An inner nacelle surrounds a core engine section and defines an inner boundary of the bypass flow passage. A panel of the inner nacelle moveable between an open position provides access to the core engine section and a closed position. A lock is supported within the inner nacelle proximate the panel. The lock includes an electric actuator for moving a locking pin between a locked position preventing opening of the panel and an unlocked position. 
         [0015]    In a further embodiment of the foregoing gas turbine engine, includes a blocker mounted to a fixed structure of the engine core blocking movement of the pin in a radial direction when the lock is in the locked position. 
         [0016]    In a further embodiment of any of the foregoing gas turbine engines, the electric actuator comprises a solenoid for moving the pin between the locked and unlocked positions. 
         [0017]    In a further embodiment of any of the foregoing gas turbine engines, the electric actuator comprises an electric motor for moving the pin between the locked and unlocked positions. 
         [0018]    In a further embodiment of any of the foregoing gas turbine engines, includes a wire harness for communicating control signals to the lock. The wire harness extends through a structure extending radially between the inner nacelle and the outer nacelle. 
         [0019]    In a further embodiment of any of the foregoing gas turbine engines, includes a switch mounted remote of the lock within the outer nacelle. 
         [0020]    In a further embodiment of any of the foregoing gas turbine engines, the switch prevents closure of a cowling when in an unlocked position. 
         [0021]    In a further embodiment of any of the foregoing gas turbine engines, includes a manual override for moving the locking pin from a locked position to an unlocked position without operating the electric actuator. 
         [0022]    A method of latching a panel of a nacelle according to an exemplary embodiment of this disclosure, among other possible things includes mounting a lock within a nacelle proximate an openable panel. The lock includes an electric actuator for moving a locking pin between a locked position preventing opening of a panel and an unlocked position, routing a wire harness to the lock for supplying electrical energy for the electric actuator and for controlling operation of the electric actuator and actuating the lock for moving the locking pin to the unlocked position and allow opening of the panel. 
         [0023]    In a further embodiment of the foregoing method, includes limiting movement of the openable panel relative to the nacelle with the locking pin in the locked position. 
         [0024]    In a further embodiment of any of the foregoing methods, includes operating a manual override for moving the locking pin from the locked position to the unlocked position without operating the electric actuator. 
         [0025]    Although the different examples have the specific components shown in the illustrations, embodiments of this disclosure are not limited to those particular combinations. It is possible to use some of the components or features from one of the examples in combination with features or components from another one of the examples. 
         [0026]    These and other features disclosed herein can be best understood from the following specification and drawings, the following of which is a brief description. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0027]      FIG. 1  is a schematic view of an example gas turbine engine. 
           [0028]      FIG. 2  is a schematic view of a forward portion of the example gas turbine engine. 
           [0029]      FIG. 3  is a schematic view of an example locking system. 
           [0030]      FIG. 4  is a schematic view of a fan cowl and actuation switch. 
           [0031]      FIG. 5  is an enlarged view of an example actuation switch. 
           [0032]      FIG. 6  is a schematic view of the example locking mechanism in an opened position. 
       
    
    
     DETAILED DESCRIPTION 
       [0033]      FIG. 1  schematically illustrates an example gas turbine engine  20  that includes a fan section  22 , and an engine core  25  including a compressor section  24 , a combustor section  26  and a turbine section  28 . Alternative engines might include an augmenter section (not shown) among other systems or features. The fan section  22  drives air along a bypass flow path B while the compressor section  24  draws air in along a core flow path C where air is compressed and communicated to a combustor section  26 . In the combustor section  26 , air is mixed with fuel and ignited to generate a high pressure exhaust gas stream that expands through the turbine section  28  where energy is extracted and utilized to drive the fan section  22  and the compressor section  24 . 
         [0034]    Although the disclosed non-limiting embodiment depicts a turbofan gas turbine engine, it should be understood that the concepts described herein are not limited to use with turbofans as the teachings may be applied to other types of turbine engines; for example a turbine engine including a three-spool architecture in which three spools concentrically rotate about a common axis and where a low spool enables a low pressure turbine to drive a fan via a gearbox, an intermediate spool that enables an intermediate pressure turbine to drive a first compressor of the compressor section, and a high spool that enables a high pressure turbine to drive a high pressure compressor of the compressor section. 
         [0035]    The example engine  20  generally includes a low speed spool  30  and a high speed spool  32  mounted for rotation about an engine central longitudinal axis A relative to an engine static structure  36  via several bearing systems  38 . It should be understood that various bearing systems  38  at various locations may alternatively or additionally be provided. 
         [0036]    The low speed spool  30  generally includes an inner shaft  40  that connects a fan  42  and a low pressure (or first) compressor section  44  to a low pressure (or first) turbine section  46 . The inner shaft  40  drives the fan  42  through a speed change device, such as a geared architecture  48 , to drive the fan  42  at a lower speed than the low speed spool  30 . The high-speed spool  32  includes an outer shaft  50  that interconnects a high pressure (or second) compressor section  52  and a high pressure (or second) turbine section  54 . The inner shaft  40  and the outer shaft  50  are concentric and rotate via the bearing systems  38  about the engine central longitudinal axis A. 
         [0037]    A combustor  56  is arranged between the high pressure compressor  52  and the high pressure turbine  54 . In one example, the high pressure turbine  54  includes at least two stages to provide a double stage high pressure turbine  54 . In another example, the high pressure turbine  54  includes only a single stage. As used herein, a “high pressure” compressor or turbine experiences a higher pressure than a corresponding “low pressure” compressor or turbine. 
         [0038]    The example low pressure turbine  46  has a pressure ratio that is greater than about 5. The pressure ratio of the example low pressure turbine  46  is measured prior to an inlet of the low pressure turbine  46  as related to the pressure measured at the outlet of the low pressure turbine  46  prior to an exhaust nozzle. 
         [0039]    A mid-turbine frame  58  of the engine static structure  36  is arranged generally between the high pressure turbine  54  and the low pressure turbine  46 . The mid-turbine frame  58  further supports bearing systems  38  in the turbine section  28  as well as setting airflow entering the low pressure turbine  46 . 
         [0040]    The core airflow C is compressed by the low pressure compressor  44  then by the high pressure compressor  52  mixed with fuel and ignited in the combustor  56  to produce high speed exhaust gases that are then expanded through the high pressure turbine  54  and low pressure turbine  46 . The mid-turbine frame  58  includes vanes  60 , which are in the core airflow path and function as an inlet guide vane for the low pressure turbine  46 . Utilizing the vane  60  of the mid-turbine frame  58  as the inlet guide vane for low pressure turbine  46  decreases the length of the low pressure turbine  46  without increasing the axial length of the mid-turbine frame  58 . Reducing or eliminating the number of vanes in the low pressure turbine  46  shortens the axial length of the turbine section  28 . Thus, the compactness of the gas turbine engine  20  is increased and a higher power density may be achieved. 
         [0041]    The disclosed gas turbine engine  20  in one example is a high-bypass geared aircraft engine. In a further example, the gas turbine engine  20  includes a bypass ratio greater than about six (6), with an example embodiment being greater than about ten (10). The example geared architecture  48  is an epicyclical gear train, such as a planetary gear system, star gear system or other known gear system, with a gear reduction ratio of greater than about 2.3. 
         [0042]    In one disclosed embodiment, the gas turbine engine  20  includes a bypass ratio greater than about ten (10:1) and the fan diameter is significantly larger than an outer diameter of the low pressure compressor  44 . It should be understood, however, that the above parameters are only exemplary of one embodiment of a gas turbine engine including a geared architecture and that the present disclosure is applicable to other gas turbine engines. 
         [0043]    A significant amount of thrust is provided by the bypass flow B due to the high bypass ratio. The fan section  22  of the engine  20  is designed for a particular flight condition—typically cruise at about 0.8 Mach and about 35,000 feet. The flight condition of 0.8 Mach and 35,000 ft., with the engine at its best fuel consumption—also known as “bucket cruise Thrust Specific Fuel Consumption (‘TSFC’)”—is the industry standard parameter of pound-mass (lbm) of fuel per hour being burned divided by pound-force (lbf) of thrust the engine produces at that minimum point. 
         [0044]    “Low fan pressure ratio” is the pressure ratio across the fan blade alone, without a Fan Exit Guide Vane (“FEGV”) system. The low fan pressure ratio as disclosed herein according to one non-limiting embodiment is less than about 1.50. In another non-limiting embodiment the low fan pressure ratio is less than about 1.45. 
         [0045]    “Low corrected fan tip speed” is the actual fan tip speed in ft/sec divided by an industry standard temperature correction of [(Tram ° R)/518.7) 0.5 ]. The “Low corrected fan tip speed”, as disclosed herein according to one non-limiting embodiment, is less than about 1150 ft/second. 
         [0046]    The example gas turbine engine includes the fan  42  that comprises in one non-limiting embodiment less than about 26 fan blades. In another non-limiting embodiment, the fan section  22  includes less than about 20 fan blades. Moreover, in one disclosed embodiment the low pressure turbine  46  includes no more than about 6 turbine rotors schematically indicated at  34 . In another non-limiting example embodiment the low pressure turbine  46  includes about 3 turbine rotors. A ratio between the number of fan blades  42  and the number of low pressure turbine rotors is between about 3.3 and about 8.6. The example low pressure turbine  46  provides the driving power to rotate the fan section  22  and therefore the relationship between the number of turbine rotors  34  in the low pressure turbine  46  and the number of blades  42  in the fan section  22  disclose an example gas turbine engine  20  with increased power transfer efficiency. 
         [0047]    A nacelle  62  is disposed about the gas turbine engine  20  and includes an outer nacelle  64  and a core nacelle  66 . The core nacelle  66  is disposed about the core engine  25  and includes an inner fixed structure  70  that is openable to allow access to the components of the core engine  25 . The inner fixed structure  70  is held in a closed position by a series of latches  72  at the bottom of the nacelle (often referred to as the latch beam) where the two nacelle halves come together. The latches  72  are accessible by mechanics from the outside of the nacelle  62 . 
         [0048]    Air pressure within the core nacelle  66  can be greater than a surrounding pressure within the bypass passage  68  disposed about the core engine nacelle  66 . This difference in pressure can result in forward edge  75  of the inner fixed structure  70  being forced outward. This outward movement of the inter-fixed structure  70  can produce a gap or opening between the openable panel  70  and the fixed structures. High speed air through the bypass passage  68  may then enter the gap and further contribute to the increases in pressure within the core engine nacelle  66 . The high speed air interaction with the outwardly displaced inner fixed structure  70  can introduce greater than desired axial forces. Moreover, once the bypass air begins or is communicated under the inner fixed structure  70 , loads produced by the airflow and increased pressures could exert high loads on the latches  72  beyond the normal intended loads. 
         [0049]    Referring to  FIGS. 2 and 3 , the example core nacelle structure  66  includes a lock  86  that corresponds with a blocker  96  to prevent outward movement of the inner fixed structure  70 . As appreciated, the inner fixed structure  70  is a panel that is openable to allow access to the core engine  25  for maintenance purposes. In typical operation, the latches  72  are unlatched and the lock  86  is moved to an unlocked position ( FIG. 6 ) to allow opening of the inter-fixed structure  70 . 
         [0050]    The example lock  86  includes an electric actuator  88  that is powered through a wiring harness  92 . The electric actuator  88  moves a pin  90  from a locked position illustrated in  FIG. 3  to an open position or unlocked position illustrated in  FIG. 6 . The pin  90  is spaced apart from the blocker  96  to define a gap  98 . A gap  98  provides for the assembly of the nacelle structure  66  and also provides tolerance for assembly maintenance. The lock  86  does not provide the latching function provided by the latches  72 . Instead, the lock  86  is a secondary feature that prevents opening of the inner fixed structure  70  in response to increased loads and pressure. 
         [0051]    The example lock  86  includes an electrical actuator  88 . In one example, the electrical actuator  88  comprises a solenoid  90  actuateable between the open and closed positions. In another disclosed embodiment, the actuator  88  comprises an electric motor to move the pin  90  between the open and closed position. As appreciated, any electrical actuator as is known may be utilized for the example lock  86  to move the pin  90  between the open and closed position. 
         [0052]    Electrical energy and control of the lock  86  is provided through the wiring harness  92 . The wiring harness  92  corresponds with a wire  84  that is threaded through the core nacelle  66  and out to the fan case  74 . In this example, a wire  84  is in communication with the wiring harness  96  and is threaded through a bifurcation  75 . As appreciated, although in the disclosed example embodiment, the wire  84  is threaded through the bifurcation  75 , the wire  84  could be threaded through other nacelle structures such as the fan exit guide vane  76  that extends between the fan case  74  and the core nacelle  66 . Use of an electrical actuator  88  for the lock  86  allows for alternate routings of the wire  84  and wire harness  92 . 
         [0053]    Referring to  FIGS. 4 and 5  with continued reference to  FIG. 3 , the example lock  86  is actuated by a switch  80  disposed on an outer surface of the fan case  74 . The fan case  74  is enclosed by a cowling  78  that is part of the outer nacelle  64 . The fan cowling  78  includes latches  82  that maintain the cowling  78  in a closed position. The switch  80  includes a lever  106  movable between a locked position indicated at  87 A and an unlocked position indicated at  87 B. The lever  106  extends from the switch  80  in the unlocked position  87   b  such that it does not allow closing of the cowling  78 . This feature provides a failsafe mechanism to ensure that the lock  86  is within a locked position when the fan cowling  78  and outer nacelle structure  62  is reinstalled to the gas turbine engine. 
         [0054]    Referring to  FIG. 6  with continued reference to  FIG. 3 , the lock  86  is shown in an open position to allow opening and maintenance of the inter-fixed structure  70 . In the open position, the pin  90  is moved away from the blocker  96  to allow movement past the blocker  96  and thereby opening of the inner fixed structure  70 . 
         [0055]    In this example the blocked  96  is attached through bracket  94  to a fixed structure about the case of the core engine  25 . The pin  90  could also interface with any fixed structure provided within the core nacelle  66  to provide the locking function that prevents opening of the inner fixed structure  70  during operation. 
         [0056]    The example lock  86  includes a manual override feature  100  that allows for opening of the pin  90  should electrical contact and control through the wire harnesses  92  and wire  84  fail. In this example, the override  100  comprises a rotatable member that engages the pin  90  to move the pin  90  to the closed position. In one example, the manual override  100  includes one portion of a worm gear assembly engaged with corresponding gear teeth on the pin  90 . A tool  104  engages a tool engagement surface  102  to facilitate rotation of the manual override  100  and thereby movement of the pin  90  to the unlocked position illustrated in  FIG. 6 . 
         [0057]    Although an example embodiment has been disclosed, a worker of ordinary skill in this art would recognize that certain modifications would come within the scope of this disclosure. For that reason, the following claims should be studied to determine the scope and content of this disclosure.