Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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AR I ULATINU SLIT) F,R TRACK
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This Application claims priority and benefit of U.S. Provisional Patent
Application Serial No. 61/304,741 filed February 15, 2.010, entitled
"Articulating Slider
Track," which is herein ifncorporated by reference in its entirety.
BACKGROUND OF TI-IE INVENTION
[0002] Embodiments disclosed herein relate generally to an articulating slider
track for a
cowl member to provide a variable area fan nozzle for a gas turbine engine,
[0003] Conventional gas turbine engines include a fan section and a core
engine with the
fan section having a larger outer diameter than that of the core engine The
fan section
and the core engine are disposed sequentially about a longitudinal axis and
are enclosed
in a nacelle. An annular path of primary airflow passes through the fan
section and the
core engine to generate primary thrust, An annular path of duct or fan flow
(bypass air),
disposed radially outward of the primary airflow path, passes through the fan
section and
exits through a fan nozzle to generate fan thrust. In general terms, the
bypass air flows
through a region defined between an outer surface of an engine core cowl and
an inner
surface of the nacelle, Such an arrangement is well known to those with skill
in the art,
[0004] The fan nozzles of certain conventional gas turbine engines have fixed
geometry.
The fixed geometry fan nozzles must be suitable for take-off and landing
conditions, as
well as for cruise conditions, However, the requirements for takeoff and
landing
conditions are different from requirements for the cruise condition, For
cruise conditions,
it is desirable to have a smaller area or smaller diameter fan nozzle for
increasing cruise
performance and for maximizing fuel efficiency, whereas, for take-oft and
landing
conditions, smaller diameter fan nozzles will create more noise and may cause
an engine
stall. Therefore, in many conventional engines the cruise performance and fuel
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efficiency are often compromised to ensure safety of the gas turbine engine at
take-off
and landing,
[0005] Some gas turbine engines have implemented variable area nozzles. The
variable
area nozzles have the ability of having a smaller fan exit nozzle diameter
during cruise
conditions and a larger fan exit nozzle diameter during take-off and landing
conditions.
l .nown existing variable area nozzles may employ complex mechanisms that
require
extensive maintenance, which is desirably avoided for commercial aircraft.
Further,
known variable area nozzle mechanisms may add significant weight to the
engine, which
adversely affects performance.
[0006] Thus, although variable area nozzles have been introduced into some gas
turbine
engines, there remains a need for a, variable area nozzle that does not
require extensive
maintenance, and does not add significant weight to the gas turbine engine.
[0007] Certain known gas turbine engine designs include thrust reverser
assemblies. For
example, known cascade type thrust reverser assemblies employ an aft
translatable cowl
(transcowl) that engages with a stationary cowl member in a nacelle assembly.
The
transcowl cooperates with a core engine cowl to define at least a. portion of
the annular
bypass duct that terminates at the exit nozzle.
[0008] Movement of the translatable cowl (transcowl) away from the stationary
cowl
member opens a passageway through which fan by-pass air may flow. A cascade
structure disposed in the passageway is selectively covered and uncovered by
movement
of the transcowl. The cascade structure includes flow directing louvers to
redirect by-
pass air outward and forward to provide reverse thrust. A plurality of
actuators may be
utilized to effect movement of the transcowl.
[0009] The thrust reverser assembly may include blocker doors that move into
the bypass
duct to inhibit passage of the bypass air through the exit nozzle.
Alternately, some thrust
reversers are known as "blacker-door-less" types in which the translatable
cowl
cooperates with the engine core cowl to inhibit passage of the bypass air
without
employing blocker doors.
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[00101 The thrust reverser assembly may include two half cowls, sometimes
referred to
as C-ducts or ducts that include upper (hinge) and lower (latch) beams, The
transcowl(s) may be mounted on rails or slider tracks fixed to upper and lower
beams.
The upper beam is the main lhinge beam that allows the thrust reverser
assembly to open
for engine access and removal, The lower beam provides a means for locking
together
the two half cowls.
[00111 It would be advantageous to utilize certain structures associated with
a translating
cowl thrust reverser assembly to provide a desired variable area fan nozzle.
BR I EF DESCRfPTION OF THE MENTION
[0012] The above-mentioned needs may be met by exemplary embodiments that
provide
an assembly comprising a first slider track able to support a first cowl
member; a support.
member; and a mechanism in supported connection with the first slider track
and the
support member; wherein the mechanism is operable to mount the first slider
track in.
articulatable relationship relative to the support member,
[00131 Another exemplary embodiment includes an assembly comprising a first
cowl
member; and a fan nozzle at least partially defined by a surface of the first
cowl member,
wherein the fan nozzle is associated with a fan nozzle exit area; and a
mechanism in
operable connection with the first cowl member being operable to slightly
modify a,
position of the first cowl member between a nominal stowed position and a
modified
stowed position. such. that the tan nozzle exit area is variable with the
position ofth e f irst.
cowl member,
[0014] Another exemplary embodiment provides a method fi r varying a fan
nozzle exit
area. The method comprises mounting a first slider track in articualtable
relationship
with a support member; mounting a first cowl member in supported slidable
relationship
with a first slider track such that a fan nozzle is at least partially defined
by a surface of
the first cowl member; varying an operational position of the first cowl
member by
articulating the first slider track without sliding the first cowl member
with. respect to the
first slider track such that the first cowl. member moves between a stowed
position and a
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modified stowed position, wherein a first nozzle exit area is associated with
the stowed
position of the first cowl member and a, second, different nozzle exit area is
associated
with the modified stowed position of the first cowl member.
BRIEF DESCRIPTION OF THE. DRAWINGS
[00151 The subject matter which is regarded as the invention is particularly
pointed out
and distinctly claimed in the concluding part of the specification. The
invention,
however, may be best understood by reference to the following description
taken in
conjunction with the accompanying drawing figures in which:
[0016] FIG. I is a schematic representation of a gas turbine engine,
[001 1 FIG. 2 is a side view of a gas turbine engine with a transcowl not
shown for
simplicity.
[0018] FIG. 3 is a schematic representation of a portion of a, thrust reverser
assembly.
[0019] FIG. 4 is a schematic top view of a hinge beam and a slider track
showing a
plurality of 4-bar linkages.
[0020] FIG. 5 is a schematic side view showing a slider track and a 4-bar
linkage.
DETAILED DESCRIPTION OF T1-11? INVIi7` TIO1
[0021] Exemplary embodiments disclosed herein provide thrust reverser
assemblies that
may be utilized to provide the desired variable area of fan exit nozzles.
[0022] FIGi. I illustrates a schematic view of selected portion of an
exernplary gas turbine
engine 10 suspended from an engine pylon 12 of an associated aircraft. The gas
turbine
engine 10 is circumferentially disposed about an engine centerline, or axial
centerline
axis A, The gas turbine engine 10 includes a. fan 14 and a core engine 16, An
outer
housing, nacelle 28 (or fan nacelle) extends circumferentially about the fan
14, A fail
bypass passage 32 extends between the nacelle 28 and an inner housing, engine
cowl 34,
which generally surrounds a low pressure compressor, a high pressure
compressor, a low
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pressure turbine, and a high pressure turbine (all not illustrated here for
simplicity, but
well known in the art).
[0023] In operation, the fan 14 draws air into the gas turbine engine 10 as a
core flow, C,
and into the bypass passage 32 as a bypass air flow, D. The bypass air flow D
is
discharged as a discharge flow through a fan nozzle 4Ã0 defined at the rear of
the nacelle
28. The fan nozzle exit area is thus defined by the position of the rear of
the nacelle in
relationship to the engine cowl 34. Exemplary embodiments disclosed herein are
operable to change the position of the rear of the nacelle relative to the
engine cowl 34,
and thus affect the i=an nozzle exit area.
[00241 In an exemplary embodiment, nacelle 28 includes a thrust reverser
assembly 50,
illustrated without the translatable cowl member in FIG, 2. In an exemplary
embodinment,
upper hinge beam 53 and lower latch beans 54 include slider tracks 58 or rails
to support
the translation of the translatable cowl member. In an c xc mplar ,T
embodiment, thrust
reverser assembly 50 is a cascade type reverser employing a cascade structure
64, as is
known in the art., In an exemplary embodiment, aft movement of the
translatable cowl
member along the slider tracks or rails uncovers the cascades 66 and opens a
passage
through which fan air is discharged in forward and outward directions. One or
more
transcowl actuators (not shown in this view) are utilized to translate the
translatable cowl
member between the stowed position and the deployed position.
[0025] With respect to FIGS. 3 and 4, translatable cowl member 52 is supported
in a
nominal stowed position during flight, and may be translated aft into one or
more
deployed positions after landing to allow fan air to be utilized for reverse
thrust as
discussed in the background section, Thrust reverser assembly 50 may include
any
configuration which utilizes one or more translatable cowl members 52 able to
translate
forward and aft in a direction generally parallel to axis A.
[0026] In exemplary embodiments, translatable cowl member 52 may be supported
in
one or more "m-rmodified" stowed positions as discussed in greater detail
below in order to
provide variation in the fan nozzle area. In an exemplary embodiment, the
slider tracks
or rails 5 are mounted in movable relationship relative to its respective
hinge or latch
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beam (hinge beam 53, shown). In an exemplary embodiment, a plurality of 4 -bar
linkages b() is utilized with each slider track such that each of the slider
tracks articulate
responsive to a track actuator 62. The 4 -bar linkages may be arranged and
coordinated
such that activation of the track actuator causes articulation of the slider
tracks and
produces slight outward motion at the rear of the translatable cowl member,
while
minimizing movement of the forward region of the translatable cowl member.
Thus the
translatable cowl member remains in a stowed position relative to the slider
tracks, but its
position is slightly modified with respect to the core cowl 34. The modified
position of
the translatable cowl member provides an opportunity for variation in the,
area of the fall
nozzle 40 as illustrated in FIG. 3. In an exemplary embodiment, in a modified
position,
the fan nozzle area may be increased as compared to the tar nozzle area when
the
translatable cowl member is in the nominal stowed position. Movement of the
track
actuator(s) 62 may be modified to provide various modified positions of the
translatable
cowl member.
[()()',)7] As illustrated in FIG. 4, in an exemplary embodiment, up to five 4-
bar linkages
maybe used for each slider track 58. In other embodiments, any, suitable
number of 4-
bar linkages may be utilized for each slider track. It is envisioned that
other mechanisms
may be utilized to provide movement of the slider track 5$ relative to its
respective
support member (upper or lower beam). Thus for a split transcowl that is
supported on
its upper and lower ends, four track actuators i ). having synchronized
motion could be
employed.
[00281 With reference to FIG. 3, a transcowl actuator 70 is illustrated.
(Although shown
as appearing to be floating, it is understood that the illustration shows an
exemplary
position of a transcowl actuator 70 understood to be coupled to the body of
revolution of
the transcowl), Those having skill in the ail will appreciate that the
transcowl actuator(s)
70 should accommodate the movement of the transcowl into the modified
position(s) due
to articulation of the slider tracks. It is envisioned that, for example,
transcowl actuators
0 may include a gimbal joint 2. Those having skill in the art will also
appreciate that
certain seals may be required. to avoid overboard leakage at the slider
tracks,
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[00291 FiG. 5 provides a side view of a slider track and one of the 4-liar
linkages.
[00301 Thus, the benefits of a variable fan nozzle area such as increased
climb thrust,
reduced noise, and improved fuel burn may be realized without complicated or
heavy
mechanisms. Because the translatable cowl member remains in a stowed position
relative to the slider tracks, safety issues associated with inadvertent
deployment of the
thrust reverser is avoided. It is envisioned that those having skill in the
art nay envision
certain modifications to the specific embodiments disclosed herein without
departing
from the general principles set forth herein,
[0031] This written description uses examples to disclose the invention,
including the
best mode, and also to enable any person skilled in the art to make and use
the invention.
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 from the
literal language of the claims, or if they include equivalent structural
elements with
insubstantial differences from the literal languages of the claims.
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