Note: Descriptions are shown in the official language in which they were submitted.
13DV11094 CA 02569179 2006-11-29
VECTORABLE NOZZLE WITH PIVOTABLE TRIANGULAR PANELS
BACKGROUND OF THE INVENTION
FIELD OF THE INVENTION
The invention relates to aircraft gas turbine engine two-dimensional vectoring
nozzles
and, more particularly, for such nozzles designed to shift center of nozzle
exhaust
Aircraft designers and particularly those designing high speed highly
maneuverable
military aircraft are constantly seeking better ways for controlling the
aircraft and
increasing its maneuverability in flight. These are needed for anti-aircraft
missile
avoidance and other combat maneuvers. Additionally, aircraft designers are
trying to
improve short take off and landing capabilities of aircraft. Exhaust systems,
particularly for modem, high speed, military aircraft, have been adapted to
provide a
high degree of maneuverability over a wide variety of flight conditions
including
altitude, speed, and Mach number while maintaining cruise efficiency.
Aircraft maneuverability may be provided by aircraft control surfaces such as
wing
flaps or ailerons or vertical fins or rudders. Aircraft control surfaces,
however, are
somewhat limited in their effectiveness because of large differences in
operational
flight conditions such as air speed. Aircraft control surfaces also increase
an aircraft's
radar signature making it more vulnerable to anti-aircraft fire and missile.
These
control surfaces are attached to the airframe with hinges. The hinges and
resulting
hinge lines reflect enemy radar. During use, these control surfaces interrupt
the
aerodynamic shape of the airframe further amplifying the return of enemy
radar.
It is, thus, highly desirable to provide an aircraft gas turbine engine with a
thrust
vectoring and low radar observability. It is also desirable to provide such a
nozzle
with a variable throat area (A8) and afterburning thrust augmentation
(desirable for
loaded takeoff and evasive maneuvers). It is also desirable to provide such a
nozzle
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13DV11094 CA 02569179 2006-11-29
with the ability to vary the nozzle exit area (A9) as well to provide for
A9/A8
variation to optimize performance over an aircraft's mission.
SUMMARY OF THE INVENTION
A vectorable nozzle includes convergent and divergent sections in serial
downstream
flow relationship with a throat therebetween and extending aftwardly from a
two-
dimensional flow nozzle inlet to a nozzle outlet. Triangular left and right
side
convergent upper panels are pivotably mounted to a triangular convergent upper
ramp
in the convergent section along left and right side convergent angled hinge
lines,
respectively. Triangular left and right side divergent upper panels are
pivotably
attached to a triangular divergent upper ramp in the divergent section along
left and
right side divergent angled hinge lines, respectively. The left and right side
convergent upper panels are in sealing engagement with the left and right side
divergent upper panels along left and right side upper interfaces,
respectively.
In an exemplary embodiment of the nozzle, the left and right side divergent
upper
panels and the left and right side convergent upper panels outwardly bound a
portion
of a nozzle flowpath of the nozzle, the left side convergent and divergent
upper panels
are operable to pivot inwardly into the nozzle flowpath while the right side
convergent
and divergent upper panels pivot outwardly from the nozzle flowpath, and the
left side
convergent and divergent upper panels are operable to pivot outwardly from the
nozzle flowpath while the right side convergent and divergent upper panels
pivot
inwardly into the nozzle flowpath. The convergent section may have a constant
width
and the divergent section may have an aftwardly diverging width. The left and
right
side convergent upper panels may have convergent trailing edges overlapping
curved
surfaces of divergent leading edges of the left and right side divergent upper
panels,
respectively.
A nozzle casing having left and right sidewalls may surround convergent and
divergent sections and side edges of the left and right side convergent upper
panels
and the left and right side divergent upper panels may be in sealing
engagement with
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convergent and divergent conically contoured portions of the left and right
sidewalls
in the convergent and divergent sections, respectively.
Another embodiment of the vectorable nozzle the nozzle center plane extending
aftwardly from the nozzle inlet to the nozzle outlet and an unvectored throat
plane
normal to the nozzle center plane. Height-wise spaced apart upper and lower
walls
outwardly bound a nozzle flowpath of the nozzle and extend aftwardly through
the
convergent and divergent sections from the nozzle inlet to the nozzle outlet.
The left
and right side upper interfaces are aligned in the unvectored throat plane
when the
throat is in an unvectored position. A pitch vectoring flap may be pivotably
attached
to the nozzle outlet at an aft end of the lower wall. One embodiment of the
lower wall
is fixed with respect to the nozzle inlet and, includes in serial downstream
relationship, a fixed rectangular convergent lower ramp attached to a fixed
divergent
lower ramp.
Another embodiment of the lower wall is variable and includes a pivotable
rectangular
convergent lower ramp pivotably mounted with respect to the nozzle inlet along
a
linear convergent ramp hinge line. A pitch vectoring flap is pivotably
attached to the
nozzle outlet at an aft end of the lower wall. The vectoring flap
substantially defines
an equilateral triangle having a base pivotably attached to the nozzle outlet
at the aft
end of the lower wall and the vectoring flap extending aftwardly from the base
to an
apex.
Yet another embodiment of the variable lower wall includes a pivotable
rectangular
convergent lower ramp pivotably mounted, with respect to the nozzle inlet,
along a
linear convergent ramp forward hinge line. Triangular left and right side
divergent
lower panels located in the divergent section are pivotably mounted to the
pivotable
convergent lower ramp along a linear convergent ramp aft hinge line. Pivotable
parallelogram shaped left and right side aftwardly swept lower panels are
pivotably
attached to left and right side aftwardly swept leading edges along left and
right side
divergent angled hinge lines of a fixed divergent lower ramp in the divergent
section,
respectively. The left and right side divergent lower panels are in sealing
engagement
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with the left and right side aftwardly swept lower panels along left and right
side
lower interfaces, respectively. The left side aftwardly swept lower panel is
in sealing
engagement with the right side aftwardly swept lower panel along a center
interface.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematical cross-sectional view illustration of a vectorable
nozzle for a
gas turbine engine installed in an aircraft.
FIG. 2 is a partially cut-away perspective view illustration of the vectorable
nozzle
illustrated in FIG. 1.
FIG. 3 is a upwardly looking perspective view illustration of an upper wall
through
convergent and divergent sections of the vectorable nozzle illustrated in FIG.
2.
FIG. 4 is an upwardly looking planform view illustration of the upper wall
illustrated
in FIG. 3.
FIG. 5 is a perspective view illustration of the vectorable nozzle illustrated
in FIG. 1.
FIG. 6 is aft looking forward view illustration of the vectorable nozzle in
FIG. 1
illustrating a throat of the nozzle in an unvectored position.
FIG. 7 is aft looking forward view illustration of the vectorable nozzle in
FIG. 1
illustrating a throat of the nozzle in a vectored position.
FIG. 8 is a schematical cross-sectional view illustration taken through the
vectorable
nozzle along 8-8 in FIG. 5.
FIG. 9 is a perspective view illustration of a fixed embodiment of a lower
wall of the
vectorable nozzle illustrated in FIG. 5.
FIG. 10 is a perspective view illustration of a variable embodiment of a lower
wall of
the vectorable nozzle illustrated in FIG. 5.
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FIG. 11 is a perspective view illustration of a second variable embodiment of
a lower
wall of the vectorable nozzle illustrated in FIG. 5.
FIG. 12 is an upwardly looking planform view illustration of the lower wall
illustrated
in FIG. 11.
FIG. 13 is a schematical aft looking forward view illustration of a right side
area of
the skewed throat taken normal to the right side area of the skewed throat of
the
vectorable nozzle illustrated in FIG. 11.
FIG. 14 is a schematical aft looking forward view illustration of a left side
area of the
throat taken normal to the left side area of the throat of the vectorable
nozzle
illustrated in FIG. 11.
FIG. 15 is an upwardly looking planform view illustration of a third variable
embodiment of the lower wall of the vectorable nozzle illustrated in FIG. 5.
FIG. 16 is a schematical cross-sectional view illustration of the third
variable
embodiment of the lower wall illustrated in FIG. 15 taken through the
vectorable
nozzle along 8-8 in FIG. 5.
DETAILED DESCRIPTION OF THE INVENTION
Schematically illustrated in cross-section in FIG. 1 is an exemplary
embodiment of an
aircraft 124 having a flush mounted engine air intake 127 connected to and in
fluid
communication with an aircraft thrust vectoring aircraft gas turbine engine 1
mounted
within the aircraft's fuselage 113. An annular fan inlet 11 of the engine 1 is
connected
to the air intake 127 by an engine fixed inlet duct 126. An inlet duct passage
111 of
the engine fixed inlet duct 126 may be two-dimensional terminating in
transition
section 119 between the inlet duct passage 111 and the axisymmetric annular
fan inlet
11. A vectorable nozzle 12 located downstream of the engine 1 is operable to
receive
an exhaust flow 15 produced by the engine 1 and vector the exhaust flow 15
sideways.
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13DV11094 CA 02569179 2006-11-29
Illustrated in FIGS. 1 and 2 is an exemplary embodiment of the vectorable
nozzle 12
fixedly connected to an aft end 6 of an engine casing 9 of the engine 1 by a
transition
duct 13. The transition duct 13 converts the exhaust flow 15 from one with a
circular
cross-section or axisymmetric exhaust flow 15 to one having a rectangular
cross-
section or two-dimensional (2D) exhaust flow 15. The nozzle 12 includes
convergent
and divergent sections 14 and 16 in serial flow relationship downstream of a
two-
dimensional flow nozzle inlet 19 at which the transition duct 13 terminates. A
throat
18 is defined between the convergent and divergent sections 14 and 16 and the
divergent section 16 terminates at a nozzle outlet 20.
Conventions used herein to describe the directions and frame of references for
the
flow and the movement of various nozzle elements include forward and aft
directions
F and A illustrated in FIGS. 1 and 2 by respective arrows. Sideway left and
right L
and R directions are illustrated by respective arrows from a frame of
reference forward
looking aft. Up and down directions U and D are illustrated in FIG. 2 by
respective
arrows. Upper and lower elements and right and left elements are used only for
describing the nozzle within the illustrated reference frame and they may be
reversed.
Referring to FIGS. 2-5, the vectorable nozzle 12 includes convergent and
divergent
sections 14 and 16 in serial downstream flow relationship with a throat 18
therebetween. The convergent section 14 of the exemplary embodiment of the
vectorable nozzle 12 illustrated herein has a constant width 70 normal to the
nozzle
center plane 22 and the divergent section 16 has an aftwardly diverging width
72. The
vectorable nozzle 12 extends aftwardly from a two-dimensional flow nozzle
inlet 19
to a nozzle outlet 20. Heightwise spaced apart flowpath bounding upper and
lower
walls 30 and 32 outwardly bound a nozzle flowpath 40 of the nozzle 12 and
extend
aftwardly through the convergent and divergent sections 14 and 16 from the
nozzle
inlet 19 to the nozzle outlet 20.
The upper wall 30 includes triangular left and right side convergent upper
panels 26
and 28 pivotably mounted to a triangular convergent upper ramp 23 in the
convergent
section 14 along left and right side convergent angled hinge lines 27 and 29,
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13DV11094 CA 02569179 2006-11-29
respectively. The upper wall 30 also has pivotable triangular left and right
side
divergent upper panels 36 and 38 pivotably attached to a chevron shaped
divergent
upper ramp 35 in the divergent section 16 along left and right side divergent
angled
hinge lines 37 and 39, respectively. The divergent section 16 includes a
triangular
trailing edge 76 defined in part by the chevron shaped divergent upper ramp 35
and
defining at least in part the nozzle outlet 20.
The left side convergent upper panel 26 is in sealing engagement with the left
side
divergent upper panel 36 along a left side interface 60. The right side
convergent
upper panel 28 is in sealing engagement with the right side divergent upper
panel 38
along a right side interface 62. The left and right side convergent upper
panels 26 and
28 have convergent trailing edges 106 overlapping curved surfaces 109 of
divergent
leading edges 110 of the left and right side divergent upper panels 36 and 38,
respectively, as illustrated more particularly in FIGS. 2, 3, and 8.
During engine operation, higher pressure in the convergent section 14 than in
the
divergent section 16 keeps the convergent trailing edges 106 of the left and
right side
convergent upper panels 26 and 28 sealed against the divergent leading edges
110 of
the left and right side divergent upper panels 36 and 38. The curved surfaces
109 of
divergent leading edges 110 provides sealing engagement of the left and right
side
convergent upper panels 26 and 28 with the left and right side divergent upper
panels
36 and 38 along the left and right side interfaces 60 and 62, respectively,
through the
full range of allowable pivoting motion of the left and right side convergent
upper
panels 26 and 28 and the left and right side divergent upper panels 36 and 38.
Referring to FIG. 5, a nozzle center plane 22 extends aftwardly from the
nozzle inlet
19 to the nozzle outlet 20 and an unvectored throat plane 24 normal to the
nozzle
center plane 22. The left and right side interfaces 60 and 62 are aligned in
the
unvectored throat plane 24 when the throat 18 is in an unvectored position. A
cross-
section of the throat 18 in the unvectored position is illustrated in FIG. 6.
The throat
18 is co-planar with the unvectored throat plane 24 and is symmetrical about
the
nozzle center plane 22.
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The vectorable nozzle 12 vectors thrust in the yaw direction (right and left)
by
pivoting the upper panels inwardly and outwardly thus pivoting the left and
right side
interfaces 60 and 62 which define a shape of the throat 18. The left side
convergent
and divergent upper panels 26 and 36 and the left side interface 60 are
operable to
pivot inwardly into the nozzle flowpath 40 while the right side convergent and
divergent upper panels 28 and 38 and the right side interface 62 pivot
outwardly from
the nozzle flowpath 40 as illustrated in FIG. 7. The left side convergent and
divergent
upper panels 26 and 36 and the left side interface 60 are also operable to
pivot
outwardly from the nozzle flowpath 40 while the right side convergent and
divergent
upper panels 28 and 38 and the right side interface 62 pivot inwardly into the
nozzle
flowpath 40.
Pivoting the upper panels inwardly and outwardly provides sonic line yaw
vectoring
by skewing or relocating the nozzle throat position and obtain a favorable
pressure
distribution to provide yaw vectoring. Pivoting the left side convergent and
divergent
upper panels 26 and 36 inwardly while pivoting the right side convergent and
divergent upper panels 28 and 38 outwardly simultaneously increases a right
side area
AR, illustrated in FIG. 13, of the throat 18 while simultaneously decreasing a
left side
area AL, illustrated in FIG. 14, of the throat an equal amount. Pivoting the
left side
convergent and divergent upper panels 26 and 36 outwardly while pivoting the
right
side convergent and divergent upper panels 28 and 38 inwardly simultaneously
decreases the right side area AR of the throat 18 while simultaneously
increasing the
left side area AL of the throat an equal amount. During vectoring a total
throat area
A8, the sum of the right side area AR and the left side area AL of the throat
18,
remains constant. The amount of vectoring increases as the side to side area
(or mass
flow) ratio AR/AL increases. During maximum vectoring the sonic line on the
right
side area AR moves aft to the right side divergent angled hinge line 39 as
illustrated in
FIG. 11
Referring to FIGS. 1, 2, 5, and 9, the exemplary embodiment of the vectorable
nozzle
12 illustrated herein includes a pitch vectoring flap 63 pivotably attached to
the nozzle
outlet 20 at an aft end 34 of the lower wall 32. The vectoring flap 63 is
operable to
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13DV11094 CA 02569179 2006-11-29
vector thrust in the pitch direction (up and down) when it is pivoted up or
down. The
vectoring flap 63 has a shape of a substantially equilateral triangle 59 with
a base 64
pivotably attached to the nozzle outlet 20 at the aft end 34 of the lower wall
32 and
extending aftwardly from the base 64 to an apex 66.
Referring to FIGS. 5, 6, and 7, the vectorable nozzle 12 includes a nozzle
casing 10
surrounding the convergent and divergent sections 14 and 16 and having left
and right
sidewalls 80 and 82. Side edges 78 of the left and right side convergent upper
panels
26 and 28 and the left and right side divergent upper panels 36 and 38 are in
sealing
engagement with convergent and divergent conically contoured portions 84 and
86 of
the left and right sidewalls 80 and 82 in the convergent and divergent
sections 14 and
16, respectively. The convergent and divergent conically contoured portions 84
and
86 are shaped or contoured to provide the sealing engagement with the left and
right
side convergent upper panels 26 and 28 and the left and right side divergent
upper
panels 36 and 38 as they pivot about the left and right side convergent angled
hinge
lines 27 and 29 and the left and right side divergent angled hinge lines 37
and 39,
respectively.
A fixed embodiment of the lower wall 32 is fixed from the nozzle inlet 19 to
the
nozzle outlet 20 as illustrated in FIG. 9. The fixed embodiment of the lower
wall 32
includes in serial downstream relationship a fixed rectangular convergent
lower ramp
90 attached to a fixed divergent lower ramp 92. The fixed nozzle inlet 19 and
the
fixed convergent and divergent lower ramps 90 and 92 are fixed with respect to
the
inlet 19 and the left and right sidewalls 80 and 82 of the nozzle 12. The
convergent
lower ramp 90 has the constant width 70 and the divergent lower ramp 92 has
the
aftwardly diverging width 72. This provides a fixed throat to exit area ratio
A9/A8
defined as an exit area A9, illustrated in FIGS. 5 and 9, divided by the
throat area A8
of the nozzle 12 illustrated in FIGS. 2 and 5.
This embodiment of the nozzle 12 can maintain a fixed throat to exit area
ratio A9/A8
even during vectored operation because the left side convergent and divergent
upper
panels 26 and 36 and the left side interface 60 are operable to pivot inwardly
into the
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13DV11094 CA 02569179 2006-11-29
nozzle flowpath 40 while the right side convergent and divergent upper panels
28 and
38 and the right side interface 62 pivot outwardly from the nozzle flowpath
40.
Furthermore, the left side convergent and divergent upper panels 26 and 36 and
the
left side interface 60 are also operable to pivot outwardly from the nozzle
flowpath 40
while the right side convergent and divergent upper panels 28 and 38 and the
right
side interface 62 pivot inwardly into the nozzle flowpath 40. Thus, by
controlling the
amount of pivot of the panels, this embodiment of the nozzle 12 can maintain
the
fixed exit to throat area ratio A9/A8 even during vectoring of the nozzles
thrust.
A first variable embodiment of the lower wall 32 extends from the nozzle inlet
19 to
the nozzle outlet 20 as illustrated in FIG. 10. This variable embodiment of
the lower
wall 32 includes a pivotable rectangular convergent lower ramp 190 pivotably
mounted, with respect to the nozzle inlet 19, along a linear convergent ramp
hinge line
130. The variable embodiment of the lower wall 32 extends from the nozzle
inlet 19
through the convergent section 14 to the throat 18 which is a variable area
throat. The
divergent lower ramp 92 is also variable having a pivotable forward section
140
pivotably connected to a fixed aft section 142. This provides a variable area
throat to
exit area ratio A8/A9. This embodiment of the nozzle 12 allows the throat area
and
thus the exit area ratio A8/A9 to be varied during vectored and unvectored
operation.
The convergent lower ramp 190 has the constant width 70 and the divergent
lower
ramp 92 has the aftwardly diverging width 72.
Referring to FIG. 10, the pivotable rectangular convergent lower ramp 190 has
a lower
convergent trailing edge 196 overlapping a lower curved surface 198 of a lower
divergent leading edge 200 of the pivotable forward section 140 of the
divergent
lower ramp 92. During engine operation, higher pressure in the convergent
section 14
than in the divergent section 16 keeps the lower convergent trailing edge 196
sealed
against the lower curved surface 198 of a divergent leading edge 200 of the
pivotable
forward section 140 of the divergent lower ramp 92. The lower curved surface
198 of
the lower divergent leading edge 200 of the pivotable forward section 140 of
the
divergent lower ramp 92 provides sealing engagement of the pivotable
rectangular
convergent lower ramp 190 with the pivotable forward section 140 of the
divergent
13DV11094 CA 02569179 2006-11-29
lower ramp 92 along a convergent divergent slidable interface 210 over the
full range
of allowable pivoting motion of the pivotable rectangular convergent lower
ramp 190
and the pivotable forward section 140 of the divergent lower ramp 92.
A second variable embodiment of the lower wall 32 extends from the nozzle
inlet 19
to the nozzle outlet 20 as illustrated in FIGS. 11 and 12. This variable
embodiment of
the lower wall 32 includes a pivotable rectangular convergent lower ramp 190
pivotably mounted, with respect to the nozzle inlet 19, along a linear
convergent ramp
forward hinge line 132. The variable lower wall 32 includes triangular left
and right
side divergent lower panels 226 and 228 in the divergent section 16. The
triangular
left and right side divergent lower panels 226 and 228 are pivotably mounted
to the
pivotable rectangular convergent lower ramp 190 along a linear convergent ramp
aft
hinge line 134. The linear convergent ramp aft hinge line 134 is normal to the
nozzle
center plane 22 and generally defines the throat 18 along the lower wall 32 in
an
unvectored position of the nozzle 12.
The variable lower wall 32 also has pivotable parallelogram shaped left and
right side
aftwardly swept lower panels 236 and 238 pivotably attached to left and right
side
aftwardly swept leading edges 246 and 248 and along left and right side
divergent
angled hinge lines 237 and 239 of a fixed divergent lower ramp 235 in the
divergent
section 16, respectively. The pitch vectoring flap 63 is pivotably attached to
the fixed
divergent lower ramp 235 at the aft end 34 of the lower wall 32.
The left side divergent lower panel 226 is in sealing engagement with the left
side
aftwardly swept lower panel 236 along a left side lower interface 160. The
right side
divergent lower panel 228 is in sealing engagement with the right side
aftwardly
swept lower panel 238 along a right side lower interface 162. The left and
right side
aftwardly swept lower panels 236 and 238 are in sealing engagement with each
other
along a center interface 240. This configuration allows the nozzle 12 to have
a bit
more vectoring as opposed to the nozzle 12 with the first two embodiments of
the
lower wall 32. Note the larger right side area AR of the throat 18 in FIG. 11.
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The amount of vectoring increases as the side to side area (or mass flow)
ratio AR/AL
increases. As the nozzle 12 is moved further toward maximum vectoring, the
sonic
line SL, illustrated in FIG. 3, on the increasing side moves farther aft or
downstream
towards the left side divergent angled hinge line 37 on the upper wall 30 and
the right
side lower interface 162. Even if the sonic line SL is skewed on only half of
the
nozzle, the larger percentage of mass flow passes over a skewed sonic line
SSL, as
illustrated in FIG. 13, since the opposite half flow area has been reduced.
The larger
mass flow on the skewed half, on the right side area AR, dominates the
direction of
exiting nozzle mass flow and provides yaw vectoring.
A third variable embodiment of the lower wall 32 extends from the nozzle inlet
19 to
the nozzle outlet 20 as illustrated in FIGS. 15 and 16. This variable
embodiment of
the lower wall 32 is similar to the one illustrated in FIGS. 11 and 12 but the
triangular
left and right side divergent lower panels 226 and 228 are pivotably mounted
to the
parallelogram shaped left and right side aftwardly swept lower panels 236 and
238 by
left and right side divergent angled first hinge lines 267 and 269 along left
and right
side aftwardly swept first leading edges 256 and 258 respectively. The left
and right
side divergent and convergent lower panels 226 and 236 are in sealing
engagement
with the pivotable rectangular convergent lower ramp 190 along a linear
convergent
ramp aft interface 244. The pivotable parallelogram shaped left and right side
aftwardly swept lower panels 236 and 238 are pivotably attached to left and
right side
aftwardly swept second leading edges 276 and 278 and along left and right side
divergent second angled hinge lines 277 and 279 of the fixed divergent lower
ramp
235 in the divergent section 16, respectively.
The pivotable panels between the sidewalls within the vectorable nozzle
provide an
aircraft gas turbine engine with a thrust vectoring and low radar
observability. The
nozzle disclosed herein also can have a variable throat area (A8) and
afterburning
thrust augmentation for loaded takeoff and evasive maneuvers. The nozzle also
has
the ability to vary the nozzle exit area (A9) as well to provide for A9/A8
variation to
optimize performance over an aircraft's mission.
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CA 02569179 2013-10-08
13DV11094
The present invention has been described in an illustrative manner. It is to
be
understood that the terminology which has been used is intended to be in the
nature of
words of description rather than of limitation. While there have been
described
herein, what are considered to be preferred and exemplary embodiments of the
present
invention, other modifications of the invention shall be apparent to those
skilled in the
art from the teachings herein and, it is, therefore, desired to be secured in
the
appended claims all such modifications as fall within the scope of the
invention.
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