The subject matter of the present disclosure relates to jet engines generally,
and more particularly to certain new and useful advances in the manufacture,
maintenance and/or operation of a segmented, deployable fan nozzle to reduce jet
engine noise and fuel consumption.
Description of Related Art
Large turbofan engines with variable flow-path geometry afford attractive
economic incentives because they reduce fuel consumption and engine noise.
However, such engines require use of variable area fan nozzles (VAFNs) to keep
critical fan parameters, such as pressure, speed and flow, within acceptable limits.
Conventional VAFN's typically employ structure known by the aircraft industry as
"chevrons" to attenuate engine noise. Triangular in shape and fixed in place, such
chevrons are typically positioned along an aft edge of a secondary exhaust nozzle of
the jet engine so that the chevrons project into the gas flow stream. Although this
arrangement has been proven to reduce jet engine noise, the chevrons cause drag and
loss of thrust because they dip into the fan stream. Accordingly, this loss of thrust
must be balanced with the need to reduce noise.
At least two types of VAFN's have been developed. VAFNs with
hydraulically-actuated chevrons are well-known, but are heavy and expensive to
maintain. VAFN's using chevrons actuated by shape memory alloys (SMA's), such
as the SMA chevrons designed and tested for the Quiet Technology Demonstrator
(QTD) I and I1 programs, offer improved noise reduction, but their high-performance
alloys, such as Nickel Titanium (NiTinol), are expensive. In the QTD I1 test, each
chevron had a laminate construction. Three SMA strips of NiTinol were positioned
on a base chevron formed of a composite laminate - two along the chevron's angled
edges, and one extending from the chevron's tip to its center - and then covered with
a cover plate. The SMA strips, which deformed in response to heat, bent each
chevron inward during takeoff to reduce community noise and cabin noise. During
cruise, the SMA strips straightened each chevron to reduce fuel consumption. In both
applications, the base of the chevrons containing the SMA strips were immovable -
e.g., did not translate forward or aft.
U.S. Patent No. 6,718,752 to Nesbitt et al. illustrates an example of such
chevrons in FIG. 21. This illustration identifies a known variable area fan nozzle
(VAFN) 2100 having flow altering components 2102 that are bent and straightened by
6
shape memory alloy (SMA) actuators.
Thus, nozzle chevrons that bend or "rotate" into and out of the stream offer
some improvement over the fixed chevrons, but are still a compromise relative to
aerodynamic performance of the nozzle. Accordingly, further improvements are
desired that allow the geometry of the nozzle and exit area to be optimized, while
providing improved acoustic attenuation, thrust and/or fuel efficiency.
BRIEF DESCRIPTION OF THE INVENTION
Described herein are embodiments of new and useful apparatus and
methods for linear actuation of flow altering components (also "chevrons") of a jet
engine variable area fan nozzle (VAFN).
Each chevron is movable, either alone or in groups of chevrons, by one or
more linear actuators forward or aft to change a diameter of a gas flow path formed in
the jet engine. In a first position, the chevrons are disposed substantially parallel the
gas flow path to attenuate drag and/or loss of engine thrust. In a second position, the
chevrons are moved aft to project, or further project, into the gas flow path. For each
linear actuator, a first component of the linear actuator is coupled with the airfoil; and
a second component of the linear actuator is coupled with the corresponding chevron.
When installed on an aircraft, each linear actuator is coupled with a controller and
with an electrical power source. A position sensor coupled with the controller is
configured to output data to the controller indicative of a position of the linear
actuator andlor a position of the chevron.
Other features and advantages of the disclosure will become apparent by
reference to the following description taken in connection with the accompanying
drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
Reference is now made briefly to the accompanying drawings, in which:
FIG. 1 is a perspective view of a jet engine;
FIG. 2 is an exploded, perspective view of an embodiment of an apparatus
configured to move a chevron forward or aft to alter a gas flow path of an airfoil for a
jet engine;
FIG. 3 is a perspective view of the embodiment of the apparatus of FIG. 2;
FIG. 4 is a perspective view of the embodiment of the apparatus of FIG. 2,
showing the apparatus in a first (default) position and positioned relative to a core
cowling of a jet engine;
FIG. 5 is a perspective view of the embodiment of the apparatus of FIG. 2,
showing the apparatus in a second (forward) position and positioned relative to the
core cowling of the jet engine;
Fig. 6 is a perspective view of the embodiment of the apparatus of FIG. 2,
showing the apparatus in a third (aft) position and positioned relative to the core
cowling of the jet engine;
FIG. 7 is a cut-away, perspective view of a second embodiment of an
apparatus configured to move a chevron forward or aft to alter a gas flow path of an
airfoil for a jet engine;
FIG. 8 is a perspective view of the second embodiment of the apparatus of
FIG. 7, showing the apparatus in a first (default) position;
FIG. 9 is a perspective view of the second embodiment of the apparatus of
FIG. 7, showing the apparatus in a second (aft) position;
FIG. 10 is a perspective view of the second embodiment of the apparatus
of FIG. 7, showing the apparatus in the first (default) position and positioned relative
to the core cowling of the jet engine;
FIG. 11 is a free-body diagram of a third embodiment of an apparatus
configured to move a chevron forward or aft to alter a gas flow path of an airfoil for a
jet engine;
FIG. 12 is a flowchart illustrating an embodiment of a method for
manufacturing embodiments of the apparatus of FIGS. 2,3,4, 5,6,7, 8,9, 10, and 11;
FIG. 13 is a flowchart illustrating an embodiment of a method for
maintaining or servicing embodiments of the apparatus of FIGS. 2, 3, 4, 5, 6, 7, 8, 9,
10, and 11;
FIG. 14 is a flowchart illustrating an embodiment of a method for
installing embodiments of the apparatus of FIGS. 2, 3, 4, 5, 6, 7, 8, 9, 10, and 11 on
an aircraft;
FIG. 15 is a flowchart illustrating an embodiment of a method for
maintaining or servicing embodiments of the apparatus of FIGS. 2, 3,4, 5, 6, 7, 8, 9,
10, and 1 1 that have been installed on an aircraft;
FIG. 16 is a high-level wiring schematic showing how embodiments of the
apparatus of FIGS. 2, 3, 4, 5, 6, 7, 8, 9, 10, and 11 are coupled with one or more
aircraft
Where applicable like reference characters designate identical or
corresponding components and units throughout the several views, which are not to
scale unless otherwise indicated.
DETAILED DESCRIPTION OF THE WENTION
As used herein, an element or function recited in the singular and
proceeded with the word "a" or "an" should be understood as not excluding plural
said elements or functions, unless such exclusion is explicitly recited. Furthermore,
references to "one embodiment" of the claimed invention should not be interpreted as
excluding the existence of additional embodiments that also incorporate the recited
features.
In brief, the present disclosure describes various embodiments of a
chevron installation that can improve operating characteristics of a jet engine, when
the jet engine is positioned within a cowl that comprises one or more linear actuators
coupled with one or more chevrons. The chevron installation includes flow altering
components, hereinafter "chevrons," and one or more linear actuators, which
translate the chevrons forward (i.e., towards the inlet end of the jet engine cowl) and
aft (i.e., towards the exhaust end of the jet engine cowl) to alter a fan nozzle exit area
to reduce noise, improve acoustic performance, and to achieve optimal fan duct
pressures at various points in the flight envelope. In one example, translating the
chevrons changes dimensions of the fan nozzle exit area and, more particularly,
positions the chevrons into the flow path of gases exiting the jet engine. For jet
engines such as high bypass turbofan engines, use of the translating chevrons can
optimize the bypass flow path nozzle size and promote acoustic attenuation.
The chevrons can translate individually or, in other examples, as groups or
sections (e.g., quadrants) comprising two or more of the chevrons. Varying the
location of the chevrons forward and aft individually or locally during flight (or
during other inherent operations of the jet engine) can optimize the engine cycleifan
duct performance and acoustic performance. In one example, the chevron(s) can be
treated andlor constructed (i.e. in one embodiment as Helmholtz resonators) to
improve the acoustic properties, e.g., the overall effective acoustic area of the fan
duct.
Examples of the actuator include linear actuators, although the chevron
installation may incorporate other types as desired. The low-profile of the linear
actuators minimizes the cross-section impact of the chevron installation on the overall
aerodynamic envelope of the jet engine. Moreover, the accuracy of linear actuators
allows precise positioning of the chevrons absent problems associated with other
types of actuators, e.g., backlash issues common to rotary actuators and mechanical
screws. One or more embodiments may also incorporate position sensing features
(e.g., as part of the linear actuator) andlor an encoder mechanism to aid in the precise
location of the chevron with respect to, e.g., the center line of the nozzle. Encoders
are useful to provide relative position feedback. For example, encoders can be
incorporated as part of linear actuators to identify relative positions of the rotor and
stator.
While this disclosure contemplates a variety of constructions, in one
example one or more of the chevrons may incorporate parts of the linear actuator as
an integral part of the chevron. This configuration can help to eliminate redundancies
in structure and assembly components. This feature can simplify the design and
implementation and, in some aspects, permit jet engines to be outfit with the
chevron(s) as part of servicing, maintenance, refurbishing or upgrading processes.
Some other features and advantages include one or more of the following
and/or combinations thereof:
(1) The chevrons can be actuated in a manner that adjusts the fan duct
nozzle cross-section area without inducing high torsional loads in a
trailing edge of the thrust reverser translating cowl;
(2) Linear actuators are inherently stiff, and may be part of the
structural load path of the translating chevron, resulting in weight
efficiencies in the design;
(3) The use of actuators on individual chevrons permits tailoring of
acoustic signature for specific conditions within a flight profile, (i.e.
take-off, cruise or approach) providing improved acoustic attenuation;
(4) Use of linear actuators allows a simple design, free from .
mechanical linkages, bell cranks, etc. that tend to degrade with age,
induce large chevron positioning tolerances and drive clearance and
positioning issues within the translating cowl assembly;
(5) Use of linear actuators allows rapid and precise positioning of one
or more chevrons; and
(6) Some capability for thrust vectoring is achieved by controlling
chevrons individually, or as selected groups.
Still other advantages and features will become apparent in connection
with the various embodiments that the disclosure presents in the discussion that
follows below.
Turning now to the figures, FIG. 1 depicts a schematic of a wing portion
100 of an aircraft that includes a jet engine 102, a pylon 104, and a wing 106. The jet
engine 102 includes a nacelle 108, which functions as an outer casing for a turbine
engine (not shown). The jet engine 102 has a forward end 110, at which air enters the
turbine engine, and an aft end 112 from which the turbine engine expels combustion
gases via, e.g., an exhaust nozzle. Near the aft end 112, the jet engine 102 comprises
an inner cowl 116 (or "core cowl 116") and an outer cowl 118 (or "thrust reverser
translating cowl 1 18"). Together the inner cowl 1 16 and the outer cowl 1 18 define a
fan nozzle exit area. The outer cowl 11 8 can comprise a plurality of chevrons 122,
which the present disclosure describes in connection with a flow nozzle/chevron
installation (or "chevron installation").
FIGS. 2, 3,4, 5, and 6 depict in various forms one exemplary embodiment
of an apparatus 200, which can be used as the chevron installation 124 (FIG. 1). FIG.
2 illustrates an exploded, perspective view of the apparatus 200, which is part of the
jet engine 102, shown in FIG. 1 but much of which has been removed for clarity. For
the present discussion, FIG. 2 identifies a forward end 210, an aft end 212, an inner
cowl 216, an outer cowl 218, and a fan nozzle exit area 220. The chevron installation
200 includes a chevron 222 and an actuator assembly 226 that moves the chevron 222
forward and aft to alter, e.g., the size and dimensions of the fan nozzle exit area 220.
FIG. 3 is a perspective view of the embodiment of the apparatus 200 of FIG. 2. Only
a portion of the outer cowl 218 is shown in FIGS. 1 and 2, so that embodiments of the
apparatus 200 may be more easily drawn, described and understood.
FIG. 4 is a perspective view of the embodiment of the apparatus 200 of
FIG. 2, showing the apparatus 200 in a first (or "default") position and positioned
relative to the inner cowl 216. FIG. 5 is a perspective view of the embodiment of the
apparatus 200 of FIG. 2, showing the apparatus 200 in a second (or "forward")
position that results after the actuator assembly 226 moves chevron 222 toward the
forward end 210. FIG. 6 is a perspective view of the embodiment of the apparatus
200 of FIG. 2, showing the apparatus in a third (or "aft") position. The aft position
occurs after the actuator assembly 226 moves the chevron 222 toward the aft end 21 2
and, in on example, closer to the inner cowl 216.
As FIG. 2 illustrates, the outer cowl 218 (or "thrust reverser translating
cowl 218") comprises a first member 228, a second member 230, and a third member
232 disposed therebetween. Near the aft end 212, the outer cowl 218 has a channel
234 that forms a gap or slot between the first member 228 and the second member
230. The outer cowl 218 also comprises a guide feature 236 proximate the channel
234. The guide feature 236 can comprise one or more guide members 238 disposed
within the channel 234 and extending longitudinally from the third member 232
toward the aft end 212. The chevron 222 has a base end 240 and a featured end 242
which tapers towards the aft end 212. In one example, the featured end 242 may have
a substantially triangular shape when viewed from the top-down or from the bottom-
UPThe
apparatus 200 also includes a cover assembly to enclose the actuator
assembly 226. The cover assembly has a first cover 246 (or "first blister 246") and a
second cover 248 (or "second blister 248") affixed to, respectively, the outer cowl 21 8
and the chevron 222. The cover assembly is generally arranged to minimize
disruptions in the air flow through the turbine engine. The shape, size, and other
features of the cover assembly prevent damage and wear to the actuator assembly 226,
while also taking into consideration fluid dynamics and aerodynamics necessary to
promote effective functioning of, e.g., jet engines. In one embodiment, both the first
cover 246 and the second cover 248 have longitudinal center axes that substantially
align with the longitudinal center axes of the outer cowl 218 and the chevron 222. To
permit movement of the actuator assembly 226 and the chevrons 222, the first cover
246 and the second cover 248 can slidably fit together, wherein one the covers (e.g.,
the first cover 246 and the second cover 248) has an opening that is large enough for
the other cover to slidably fit therein.
The base end 240 can comprise one or more receiving features (not shown)
such as slots or holes that can receive the guide members 238. The base end 240
likewise can fit into the channel 234 so that the chevron 222 can slidably engage the
outer cowl 218. The guide members 238 are useful to prevent radial motion of the
chevron 222, either inward towards the engine centerline or outward. These elements
also guide the chevron 222 forward and aft, and provide a wear surface that can
prevent vibration, air gaps, etc. In other examples, the guide members can also serve
other functions including as a mechanism that permits the chevron to return to a
position (e.g., the default position) in the event of power low to the linear actuator.
FIG. 2 shows that the second member 230 may extend farther towards the
aft end 212 than the first member 228. In one example, the second member 230 may
taper in thickness toward the aft end 212. These features can smooth the transition
from the second member 230 to the chevron 222 to provide better aerodynamics and
related fluid dynamic properties between the outer cowl 21 8 and the chevron 222. In
one embodiment, the outer cowl 218 andlor the base end 240 can comprise
interlocking features, in lieu of the individually formed guide members 238, that
permit movement of the chevron 222 relative to the outer cowl 21 8 but also stabilize
the chevron 222.
As best shown in FIG. 3, an embodiment of the actuator assembly 226
includes a linear actuator 250, which is preferably an electromagnetic linear motor
with a rotor 252 that is slidably coupled with a stator 254. One or more fasteners 256
secure the stator 254 to the outer cowl 218. Suitable linear motors for use as the
linear actuator 250 are known and readily available, and thus do not warrant a detailed
discussion herein of how they are constructed and function. The actuator assembly
226 also comprises a support structure 258 that secures the linear actuator 250 to the
chevron 222.
In one embodiment, the support structure 258 comprises a tang 260, which
is affixed proximate the base end 240 of the chevron 222, and a pair of opposing
support members 262 secured to the linear actuator 250. The support members 262
form a clevis fitting that can integrate with the tang 260. In one example, a pin 264
couples the support members 262 to the tang 260 such as through openings (e.g.,
holes, bores, apertures, etc.) present in each of the tang 260 and the support members
262.
In operation, the rotor 252 moves forward and aft in response to electrical
current applied to the linear actuator 250 andlor in response to magnetic fields
generated by the linear actuator 250. Movement of the rotor 252 directs force to the
chevron 222 via, e.g., the support structure 258, to move the chevron 222 forward and
aft as prescribed herein. Prior to installation, the linear actuator 250 should be tested
and certified for use onboard an jet engine. The linear actuator 250 should also be
capable of translating the chevron 222 towards the aft end 212 and into the flow path
of combustion gases that the jet engine expels, and capable of operating with high
translating forces so as to translate one or more of the chevrons into the gas flow path
when the jet engine is in operation.
FIGS. 4, 5, and 6 show the outer cowl 218 and the chevron 222 in relation
to the inner cowl 216 of the jet engine. This configuration forms the fan nozzle exit
area 220 through which the gases flow in a gas flow path 264. In FIG. 4, the linear
actuator 250 and the chevron 222 are in a first (default) position, where a gap distance
266 separates the base end 240 of the chevron 222 from the aft-facing end of the third
member 232. In FIG. 5, the linear actuator 250 and the chevron 222 are in a second
(also "forward" or "retracted") position, where the gap distance 266 is reduced. In
one example, the chevron 222 retracts so the base end 240 mates substantially with
the aft-facing surface of the third member 232, thereby forming a hard stop that

the rotor 352 to the flanges 380. In one example, the apparatus 300 may include
fasteners and suitable bracketry that secure the linear actuator 350 to each of the outer
cowl 318 and the chevron 322. In other examples, one or more components of the
linear actuator 350 may be integrally formed with the base end 340 of the chevron
322.
Referring to FIGS. 7, 8, and 9, the chevron 320 is installed within the area
372 so that the base end 340 fits within and can translate between the outer member
368 and the platform 374 in the outer cowl 3 18 (or "translating sleeve" as this element
may also be known). In the present example, the linear actuator 350 is also housed
within the chevron 322 and enclosed by, e.g., the outer member 368. In FIGS. 7 and
8, the chevron 320 is shown in a nominal position, forming the gap distance 366, and
from which the chevron 320 may be actuated either forward or aft to achieve different
nozzle throat and acoustic attenuation. For example, when the linear actuator 350 is
energized, the chevron 320 translates forward or aft as necessary, altering the
relationship of the outer cowl 318 to the inner cowl 316, and in turn altering the
diameter of the fan nozzle exit area 322. The degree of changes in this relationship
can be defined by the gap distance 366. In FIG. 9, the gap distance 366 increases as
the chevron 322 translates aft.
FIG. 10 is a perspective view of the apparatus 300 of FIG. 8, showing the
apparatus 300 in the first position in relation to the core cowl 3 16 of the jet engine.
FIG. 11 is a free-body diagram of a third embodiment of an apparatus 400
configured to move a chevron 422 forward or aft to alter a gas flow path in a jet
engine (e.g., the jet engine 102 of previous figures). In FIG. 11, the outer member
(e.g., the outer member 218, 318 in prior figures) and guide members (e.g., the guide
members 228, 382 in prior figures) of the outer cowl 418 have been omitted for
clarity.
More importantly, FIG. 11 illustrates an exemplary construction in which
the chevron 422 has a base end 440 that incorporates a component of the linear
actuator 450. For example, the apparatus 400 includes a bracket 490 that is housed
within the area 476 formed in the afi end of the outer cowl 418 and is attached to the
outer cowl 418. The stator 454 of the linear actuator 450 is attached to the support
bracket 490 and slidably fits within a channel 492 formed in the base end 440 of the
chevron 442. The rotor (not shown) of the linear actuator 450 is integrally formed
with the base end 440 of the chevron 442 and includes one or more magnets 494
housed therein. The chevron 422 is retained by a spring 496. One end of the spring
496 attached to the chevron 422; the other is attached to the bracket 490, the stator
454, andlor elsewhere in the area 476 formed in the outer cowl 418. The apparatus
400 may also include a position sensor 498, which is in one example integrally
formed in the chevron 422. The position sensor 498 may be coupled to a controller
(e.g., a controller 808 in FIG. 17) via a wired connection or wireless connection. In
use, the position sensor 490 senses the precise position of at least one of the linear
actuator 450 and the chevron 422. The sensor 490 can output data indicative of that
precise position to the controller (e.g., the controller 808 in FIG. 17).
FIG. 12 is a flowchart illustrating an embodiment of a method 500 for
manufacturing embodiments of the apparatus 200,300,400 of FIGS. 2,3,4,5,6,7, 8,
9, 10, and 11. The method 500 can include, at block 502, fastening a chevron to a
linear actuator and, at block 504, fastening the linear actuator to the cowl or other
portion of the jet engine.
Generally the method 500 can be used in the manufacture of jet engines at
the factory or, in other environments, as a way to equip existing jet engines with one
or more of the apparatus discussed above. For new builds, integration of any one of
the apparatus 200, 300, and 400 may be better suited. Designs that require integration
of specific components may be identified prior to finalization of the design and, thus,
one or more components of the jet engine can be specifically manufactured as per
specifications of the apparatus 200, 300 ,and 400. On the other hand, integration of
the chevron installation into existing jet engines may require more intensive
construction/rebuilding efforts to achieve successful integration. Additional steps
may require that the jet engine be taken apart, and that certain components be
modified (e.g., by machining, welding, boring, etc.) to accommodate one or more of
the components that the present disclosure contemplates herein.
In connection with servicing and refurbishing of existing jet engines, FIG.
13 is a flowchart that illustrates an embodiment of a method 600 for maintaining or
servicing embodiments of the apparatus 200, 300, 400 of FIGS. 2, 3, 4, 5, 6, 7, 8, 9,
10, and 11. The method 600 includes, at block 602, unfastening a chevron from the
jet engine from existing structure, at block 604, fastening the same chevron to a linear
actuator and, at block 606, fastening the linear actuator to the cowl or other portion of
the jet engine.
When dealing with existing engines, it may be likely to encounter
chevrons that are previously secured to other components for translation. Existing
configurations of the chevrons may, for example, translate and or actuate in different
manners and for reasons that are different than those contemplated herein. It may be
reasonable to consider the implementation of various other devices that may facilitate
the removal and reinsertion of the chevron including, for example, embodiments in
which positioning of stanchions and machining tools and equipment is necessary.
FIG. 14 is a flowchart illustrating an embodiment of a method 700 for
installing embodiments of the apparatus 200, 300, 400 of FIGS. 2, 3, 4, 5, 6, 7, 8, 9,
10, and 11 on an jet engine. The method 700 includes, at block 702, positioning a
position sensor to sense movement of a chevron. The method 700 also includes, at
block 704, coupling a controller to the positioning sensor and the linear actuator. The
method 700 fbrther includes, at block 706, coupling a power source (e.g., an electrical
power source) to the linear actuator.
The method 700 can also include other steps, including steps found in
embodiments of the method 500 and 600. At a high level, the positioning sensor is
useful to monitor the position of the chevron and, more importantly, to determine how
far the chevron extends into the flow path of combustion gases. The position sensor
can be, in one example, proximate the chevron and/or a portion of the linear actuator.
In other examples, the positioning sensor can be incorporated as part of the linear
actuator or other device (e.g., an encoder) that provides inputs suitable for monitoring
and determining the location of the chevron as contemplated herein.
FIG. 15 is a flowchart illustrating an embodiment of another method 800
for maintaining or servicing embodiments of the apparatus 100, 200, 300 of FIGS. 2,
3, 4, 5, 6, 7, 8, 9, 10, and 11 that have been installed on an aircraft. The method 800
can also be performed in conjunction with the other methods (e.g., the methods 500,
600, 700 or the previous figures) to outfit previously-built jet engines with equipment
necessary to provide adjustable chevrons as disclosed herein.
The method 800 includes, at block 802, de-coupling a power source from
an actuator and, at block 804, de-coupling a controller from the actuator. The method
800 also includes, at block 806, de-coupling a position sensor from one or more of the
controller, chevron, and actuator. The method 800 can further include, at block 808,
replacing one or more of the actuator, the controller, the position sensor, and the
chevron.
As discussed above, some embodiments of the apparatus 200, 300, 400
may be installed on jet engines with existing hardware for causing movement of the
chevrons disposed thereon. Some or all of this hardware may be replaced to facilitate
the use of the improved chevron installation of the present disclosure. For example,
the actuators may be replaced with linear actuators that provide better performance,
accuracy, and a lower profile. The chevrons may not be equipped to interface with
the linear actuators thus, in one example, replacement chevrons are provided and
installed as necessary. Still other examples of the present disclosure contemplate
upgrades to the controller, the power supply, or other elements of the control systems
to promote activation and implementation of the apparatuses described above.
FIG. 16 is a high-level wiring schematic showing how embodiments of the
apparatus 200, 300,400 of FIGS. 2, 3,4, 5, 6,7, 8,9, 10, and 11 are coupled with one
or more aircraft components. Generally a variety of control configurations can be
used to implement the concepts of the present disclosure. Such control configurations
are, more typically, dictated by the control structure of the jet engine andlor the
aircraft on which the jet engine is assembled. The example of FIG. 16 provides a
schematic diagram of one structure 900 that includes an operator interface 902, a
power source 904, a linear actuator 906, and a controller 908. The configuration 900
also includes a position sensor 910, a thrust reverser position sensor 912, an actuator
9 14, and a thrust reverser 9 16.
The controller 908 may include various components such as a processor, a
memory, and control circuitry configured for general operation of the devices and
system on the aircraft, jet engine, and the like. Collectively the parts of the controller
908 execute high-level logic functions, algorithms, as well as fumware and software
instructions. In one example, the processor is a central processing unit (CPU) such as
an ASIC and/or an FPGA. The processor can also include state machine circuitry or
other suitable components capable of receiving inputs from the positioning sensor
910. The memory includes volatile and non-volatile memory and can be used for
storage of software (or firmware) instructions and configuration settings. In some
embodiments, the processor, the memory, and control circuitry can be contained in a
single integrated circuit (IC) or other component. As another example, the processor
can include internal program memory such as RAM andor ROM. Similarly, any one
or more of functions of these components can be distributed across additional
components (e.g., multiple processors or other components).
The operator interface 902 can be part of an display, such as would be
found in the cockpit of an aircraft. The operator interface 902 can provide a graphic
user interface ("GUI"). In one example, the GUI identifies the position of the chevron
relative to the inner cowl or, in one construction, relative to another fixed location on
the jet engine and/or wing. In another example, the configuration 900 may include a
flow meter, sensor, or other flow detection device that monitors parameters for the
combustion gas exiting the jet engine. This information can be used to determine the
correct position of the chevron, and prompt manual andor automated response to
activate the linear actuator and change the position as desired.
A small sample of exemplary embodiments follows below in which:
In one embodiment, a chevron comprising a featured end that tapers to a
pointed tip and a base end comprising a cavity, the cavity comprising a slot
configured to receive a component of a linear actuator therein.
In one embodiment, the chevron of paragraph [0068], wherein the chevron
is further configured to be secured to one or more linear slides.
In one embodiment, the chevron of claim [0068], wherein the base end
comprises a slot to receive a guide member therein.
In one embodiment, a thrust reverser translating cowl comprising an aft
end with a channel, wherein the channel is sized to receive a base end of a chevron
therein.
In one embodiment, the thrust reverser translating cowl of paragraph
[007 11, wherein the channel is formed between a first member and a second member.
In one embodiment, the thrust reverser translating cowl of paragraph
LO07 11, wherein the channel has an open top end forming an area of reduced diameter
at the aft end.
In one embodiment, a method to secure a chevron to a jet engine, said
method comprising fastening the chevron to a linear actuator and fastening the linear
actuator to an outer cowl of the jet engine, wherein the chevron is movable by the
linear actuator forward or aft to change the position of the chevron relative to a gas
flow path formed by the outer cowl and an inner cowl of the jet engine.
In one embodiment, the method of paragraph [0074], further comprising
unfastening the chevron from the jet engine and replacing an actuator with the linear
actuator.
In one embodiment, the method of paragraph [0074], wherein the linear
actuator is secured to each of the outer cowl and the inner cowl.
In one embodiment, the method of paragraph [0074], wherein the chevron
has a base end that fits within a channel of the outer cowl.
It is contemplated that, where applicable in the present disclosure,
numerical values, as well as other values that are recited herein are modified by the
term "about", whether expressly stated or inherently derived by the discussion of the
present disclosure. As used herein, the term "about" defines the numerical boundaries
of the modified values so as to include, but not be limited to, tolerances and values up
to, and including the numerical value so modified. That is, numerical values can
include the actual value that is expressly stated, as well as other values that are, or can
be, the decimal, fractional, or other multiple of the actual value indicated, andlor
described in the disclosure.
This written description uses examples to disclose embodiments of the
invention, including the best mode, and also to enable any person skilled in the art to
practice the invention, including making and using any devices or systems and
performing any incorporated methods. The patentable scope of the invention is
defined by the claims, and may include other examples that occur to those skilled in
the art. Such other examples are intended to be within the scope of the claims if they
have structural elements that do not differ fiom the literal language of the claims, or if
they include equivalent structural elements with insubstantial differences fiom the
literal language of the claims.

Claims
1. A trans cowl for use in a jet engine and forming a gas flow path with an
inner cowl through which gases can exit, said trans cowl comprising:
a chevron; and
a linear actuator coupled with the chevrons,
wherein the chevron is movable by the linear actuator forward or aft to change
the position of the chevron relative to the gas flow path.
2. The trans cowl of claim 1, wherein in a first position, the chevron is
disposed substantially parallel to the gas flow path to attenuate drag andlor loss of
engine thrust.
3. The trans cowl of claim 2, wherein in a second position, the chevron is
translated aft to project into the gas flow path.
4. The trans cowl of claim 1, wherein the linear actuator is coupled with an
outer member of the trans cowl.
5. The trans cowl of claim 4, wherein the chevron has a base end that is
disposed in a channel formed between the outer member and an inner member of the
trans cowl.
6. The trans cowl of claim 1, further comprising
a housing assembly coupled to the chevron, wherein the housing assembly is
configured to house the linear actuator, and wherein the housing assembly is
configured to permit translation of the linear actuator to extend and retract the
chevron relative to the gas flow path.
7. The trans cowl of claim 6, wherein the housing assembly comprises a first
housing coupled to an outer member of the trans cowl.
8. The trans cowl of claim 7, wherein the housing assembly comprises a
second housing that is coupled to the chevron, and wherein the second housing
slidably fits with the first housing.
9. The trans cowl of claim 1, further comprising a controller coupled with the
linear actuator.
10. The trans cowl of claim 9, further comprising:
a position sensor coupled with the controller and configured to output data to
the controller indicative of a position of the linear actuator and/or a position of the
chevron.
1 1. An apparatus for changing a gas flow path formed in a jet engine by an
inner cowl and an outer cowl, said apparatus comprising:
a chevron;
a linear actuator coupled to the chevron and to an outer cowl of the jet engine,
wherein the chevron is movable by the linear actuator forward or aft to change
the position of the chevron relative to the gas flow path
12. The apparatus of claim 1 1, further comprising:
a tang disposed on the chevron, wherein the tang forms a clevis fitting with
opposing structural members of the linear actuator.
13. The apparatus of claim 1 1, further comprising a housing assembly secured
to an outer member of the outer cowl and to the chevron.
14. The apparatus according to claim 11, wherein the chevron comprises a
slot that is sized and configured to receive a component of the linear actuator therein.
15. A apparatus for positioning a chevron, said apparatus comprising:
a linear actuator;
a chevron having a base end configured to fit within a corresponding channel
on a trans cowl;
a guide member secured to the trans cowl and the chevron,
wherein the chevron is movable by the linear actuator forward or aft to change
the position of the chevron relative to the gas flow path.
16. The apparatus of claim 15, wherein the guide members comprise a linear
slide.
17. The apparatus of claim 15, further comprising:
a housing assembly that can be secured to each of the outer cowl and the
chevron, wherein the housing assembly encloses the linear actuator therein.
18. The apparatus of claim 15, further comprising:
a position sensor coupled to a controller on an aircraft, the position sensor
configured to output data to the controller indicative of a position of the linear
actuator and/or a position of the chevron.
19. The apparatus of claim 15, fiuther comprising:
a support structure that forms a clevis fitting with the chevron.
20. The apparatus of claim 19, wherein the support structure comprises
opposing structural members and a pin that interfaces with a tang disposed on the
chevron.
Agent for the Applicant [IN/PA-7401
LEX ORBlS
Intellectual Property Practice
70917 10, Tolstoy House,
15- 17, Tolstoy Marg,
New Delhi-I I0001