U.S. patent application number 10/868238 was filed with the patent office on 2005-12-15 for methods and apparatuses for controlling airflow proximate to engine/airfoil systems.
Invention is credited to Dun, Roy.
Application Number | 20050274846 10/868238 |
Document ID | / |
Family ID | 35459510 |
Filed Date | 2005-12-15 |
United States Patent
Application |
20050274846 |
Kind Code |
A1 |
Dun, Roy |
December 15, 2005 |
METHODS AND APPARATUSES FOR CONTROLLING AIRFLOW PROXIMATE TO
ENGINE/AIRFOIL SYSTEMS
Abstract
Methods and apparatuses for controlling airflow proximate to
engine/airfoil systems are disclosed. In one embodiment, an
aircraft system includes an airfoil and an engine unit at least
proximate to the airfoil with a gap between a portion of the
airfoil and a portion of the engine unit. The system can further
include a flow control device proximate to the gap and positionable
among at least three stationary positions, including a retracted
position in which the gap has a first area through which fluid can
flow, a first extended position in which the gap is at least
approximately aerodynamically sealed, and a second extended
position in which the gap has a second smaller area through which
fluid can flow. A control system can be coupled to the flow control
device to move the flow control device among these positions.
Inventors: |
Dun, Roy; (Seattle,
WA) |
Correspondence
Address: |
PERKINS COIE LLP
PATENT-SEA
P.O. BOX 1247
SEATTLE
WA
98111-1247
US
|
Family ID: |
35459510 |
Appl. No.: |
10/868238 |
Filed: |
June 15, 2004 |
Current U.S.
Class: |
244/55 ;
244/130 |
Current CPC
Class: |
B64D 27/18 20130101;
B64C 9/24 20130101; Y02T 50/32 20130101; Y02T 50/30 20130101; B64C
7/02 20130101 |
Class at
Publication: |
244/055 ;
244/130 |
International
Class: |
B64C 029/00 |
Claims
1. An aircraft system comprising: an airfoil; an engine unit having
a housing at least proximate to the airfoil with a gap extending
between a portion of the airfoil and a portion of the housing of
the engine unit; and a flow control device proximate to the gap and
positionable among at least three stationary positions, including:
a retracted position in which the gap has a first area through
which fluid flows during flight, a first extended position in which
the gap is at least approximately aerodynamically sealed during
flight; and a second extended position in which the gap has a
second area through which fluid flows during flight, the second
area being smaller than the first area.
2. The system of claim 1 wherein the flow control device includes
multiple flow surface sections movable relative to each other.
3. The system of claim 1 wherein the engine unit includes a pylon,
the engine unit being coupled to the airfoil via the pylon, the
engine unit being positioned under the airfoil with a portion of
the engine unit extending forward of a leading edge of the
airfoil.
4. The system of claim 1 wherein the flow control device is coupled
to the airfoil.
5. The system of claim 1 wherein the engine unit includes a pylon
and the flow control device is coupled to the pylon.
6. The system of claim 1 wherein the flow control device is coupled
to the housing.
7. The system of claim 1 wherein the engine unit includes a thrust
reverser, at least a portion of the engine housing being coupled to
the thrust reverser to move when the thrust reverser is deployed,
and wherein at least a portion of the flow control device moves
with the engine housing when the flow control device is in the
first extended position.
8. The system of claim 1, further comprising a control system
coupled to the flow control device to position the flow control
device among the retracted, first extended, and second extended
positions.
9. The system of claim 1, further comprising a control system
coupled to the flow control device to position the flow control
device among the retracted, first extended, and second extended
positions, the control system having at least one actuator, the at
least one actuator including at least one hydraulic actuator.
10. The system of claim 1, further comprising a control system
coupled to the flow control device to position the flow control
device among the retracted, first extended, and second extended
positions, the control system having at least one actuator, the at
least one actuator including at least one electric actuator.
11. The system of claim 1, further comprising a control system
coupled to the flow control device to position the flow control
device among the retracted, first extended, and second extended
positions, at least a portion of the control system including a
computer.
12. The system of claim 1, further comprising a control system
coupled to the flow control device to position the flow control
device among the retracted, first extended, and second extended
positions, the control system including: a first actuator coupled
to the flow control device to position the flow control device
between the retracted and first extended positions; and a second
actuator coupled to the flow control device to position the flow
control device between the first and second extended positions.
13. The system of claim 1, further comprising a control system
coupled to the flow control device to position the flow control
device among the retracted, first extended, and second extended
positions, wherein the flow control device includes a first portion
and a second portion and wherein only the second portion of the
flow control device moves when the flow control device is
positioned between the first extended position and the second
extended position.
14. The system of claim 1 wherein the airfoil includes at least one
leading edge device laterally disposed from the flow control device
and wherein the flow control device is at least approximately
aerodynamically sealed against a portion of a lateral edge of the
leading edge device when the flow control device is in at least one
of the first and second extended positions.
15. The system of claim 1 wherein the engine unit includes a pylon
and wherein the flow control device is at least approximately
aerodynamically sealed against at least a portion of the pylon.
16. The system of claim 1 wherein the engine unit includes a pylon,
the engine unit being coupled to the airfoil via the pylon, the
engine unit being positioned under the airfoil with a portion of
the engine unit extending forward of the leading edge of the
airfoil, a portion of the pylon being positioned behind the
gap.
17. The system of claim 1 wherein the airfoil, engine unit, and
flow control device are installed on an aircraft.
18. The system of claim 1 wherein the flow control device includes
a Krueger flap.
19. The system of claim 1 wherein the flow control device includes
a slat.
20. The system of claim 1 wherein the flow control device includes
a variable camber leading edge device.
21. The system of claim 1, further comprising a control system
coupled to the flow control device to position the flow control
device among the retracted, first extended, and second extended
positions, the control system including: a first actuator coupled
to the flow control device to position the flow control device
between the retracted and first extended positions; and a second
actuator coupled to the flow control device to position the flow
control device between the first and second extended positions; and
wherein: the engine unit includes a pylon, the engine unit being
coupled to the airfoil via the pylon, the engine unit being
positioned under the airfoil with a portion of the engine unit
extending forward of a leading edge of the airfoil; and the flow
control device depends from the airfoil and includes multiple flow
surface sections movable relative to each other.
22. An aircraft system comprising: an airfoil; an engine unit at
least proximate to the airfoil, the engine unit including a pylon
and a housing, the engine unit being coupled to the airfoil via the
pylon, the engine unit being positioned under the airfoil with a
portion of the engine unit extending forward of a leading edge of
the airfoil, a gap extending between a portion of the housing and a
portion of the leading edge of the airfoil; a flow control device
coupled to the airfoil and having multiple flow surface sections
movable relative to each other, the flow control device being
positionable among at least three stationary positions, including:
a retracted position in which the gap has a first area through
which fluid can flow; a first extended position in which the gap is
at least approximately aerodynamically sealed; and a second
extended position in which the gap has a second area through which
fluid can flow, the second area being smaller than the first area;
and a control system coupled to the flow control device to position
the flow control device among the retracted, first extended, and
second extended positions, the control system including: a first
actuator coupled to the flow control device to position the flow
control device between the retracted and first extended positions;
and a second actuator coupled to the flow control device to
position the flow control device between the first and second
extended positions.
23. The system of claim 22 wherein the airfoil, engine unit, and
flow control device are installed on an aircraft.
24. An aircraft system comprising: an airfoil; an engine unit at
least proximate to the airfoil with a gap between a portion of the
airfoil and a portion of the engine unit; and a flow control means
for controlling the flow of fluid through the gap, the flow control
means having at least three stationary positions, including: a
retracted position in which the gap has a first area through which
fluid can flow; a first extended position in which the gap is at
least approximately aerodynamically sealed; and a second extended
position in which the gap has a second area through which fluid can
flow, the second area being smaller than the first area.
25. The system of claim 24 wherein the airfoil, engine unit, and
flow control means are installed on an aircraft.
26. A method for making an aircraft system comprising: installing a
flow control device at least proximate to an airfoil and an engine
unit having a housing; coupling a control system to the flow
control device; and configuring the control system to position the
flow control device among at least three stationary positions,
including: a retracted position in which a gap extending between a
portion of the airfoil and a portion of the housing of the engine
unit has a first area through which fluid flows during flight; a
first extended position in which the gap is at least approximately
aerodynamically sealed during flight; and a second extended
position in which the gap has a second area through which fluid
flows during flight, the second area being smaller than the first
area.
27. The method of claim 26 wherein installing a flow control device
includes installing a flow control device having multiple flow
surface sections that are movable relative to each other.
28. The method of claim 26 wherein installing a flow control device
at least proximate to an airfoil and an engine unit includes
installing a flow control device proximate to an airfoil and an
engine unit on an aircraft, the engine unit having a pylon, the
engine unit being coupled to the airfoil via the pylon, the engine
unit being positioned under the airfoil with a portion of the
engine unit extending forward of a leading edge of the airfoil.
29. The method of claim 26 wherein installing a flow control device
includes coupling a flow control device to the airfoil.
30. The method of claim 26 wherein installing a flow control device
includes coupling a flow control device to a portion of the engine
unit.
31. The method of claim 26 wherein configuring a control system
includes configuring a computer.
32. The method of claim 26 wherein configuring the control system
to position the flow control device includes configuring the
control system to position the flow control device in the second
extended position to increase at least one of a maximum lift
coefficient or a lift to drag ratio of a portion of the
airfoil.
33. The method of claim 26 wherein configuring the control system
to position the flow control device includes configuring the
control system to position the flow control device in the first
extended position to increase at least one of a maximum lift
coefficient or a lift to drag ratio of a portion of the
airfoil.
34. The method of claim 26 wherein configuring the control system
to position the flow control device includes configuring the
control system to position the flow control device in the first
extended position to decrease the drag coefficient of a portion of
the airfoil.
35. The method of claim 26 wherein configuring the control system
to position the flow control device includes configuring the
control system to position the flow control device in the second
extended position to decrease the drag coefficient of a portion of
the airfoil.
36. The method of claim 26 wherein installing a flow control device
at least proximate to an airfoil and an engine unit includes
coupling a flow control device to an airfoil on an aircraft, the
flow control device having multiple flow surface sections that are
movable relative to each other, the engine unit having a pylon, the
engine unit being coupled to the airfoil via the pylon, the engine
unit being positioned under the airfoil with a portion of the
engine unit extending forward of a leading edge of the airfoil.
37. A method for operating an aircraft comprising: positioning a
flow control device of the aircraft in a first extended position in
which a gap extending between a portion of an airfoil and a portion
of a housing of an engine unit is at least approximately
aerodynamically sealed during flight; flying the aircraft with the
flow control device in the first extended position; positioning the
flow control device of the aircraft in a retracted position in
which the gap has a first area through which air flows during
flight; flying the aircraft with the flow control device in the
retracted position; positioning the flow control device of the
aircraft in a second extended position in which the gap has a
second area through which air flows during flight, the second area
being smaller than the first area; and flying the aircraft with the
flow control device in the second extended position.
38. The method of claim 37 wherein flying the aircraft with the
flow control device in the retracted position includes flying the
aircraft during a cruise phase of flight with the flow control
device in the retracted position.
39. The method of claim 37 wherein flying the aircraft with the
flow control device in the first extended position includes flying
the aircraft during a takeoff phase of flight with the flow control
device in the first extended position.
40. The method of claim 37 wherein flying the aircraft with the
flow control device in the second extended position includes flying
the aircraft during a landing phase of flight with the flow control
device in the second extended position.
Description
TECHNICAL FIELD
[0001] Embodiments of the present invention relate to methods and
apparatuses for controlling airflow proximate to engine/airfoil
systems, for example, on aircraft with wing-mounted engine
units.
BACKGROUND
[0002] Many modern-day aircraft include leading edge high lift
devices (e.g., slats and Krueger flaps) to improve performance
during certain phases of flight (e.g., takeoff and landing). Many
of these aircraft also have wing-mounted propulsion units that are
carried under the wing of the aircraft. The wing-mounted propulsion
units can interfere with flow over the wing and detract from
aircraft performance.
[0003] FIG. 1A is a partially schematic top plan view and FIG. 1B
is a partially schematic front elevation view of an aircraft wing
10 having a wing-mounted propulsion unit 20 in accordance with the
prior art. The wing 10 can include an inboard high lift leading
edge device 12a and an outboard high lift leading edge device 12b.
The propulsion unit 20 can include an engine 26, positioned within
a housing 22, which is supported by a pylon 21. The propulsion unit
20 can be coupled to the wing 10 via the pylon 21 so that at least
a portion of the propulsion unit 20, including the pylon 21,
extends forward from the leading edge 11 of the wing 10.
Accordingly, there can be a gap 5 between a portion of the housing
22 and a portion of the wing 10. This gap 5 can be a major
contributor to the flow interference created by the wing-mounted
propulsion unit arrangement.
[0004] The local flow pattern around and through the gap 5 can be
quite complex, especially when the aircraft is operated at higher
angles of attack and/or when the high lift leading edge devices
12a, 12b are deployed. The interface between the wing 10 and
propulsion unit 20, including the gap 5, is often optimized for the
cruise condition when the high lift leading edge devices 12a, 12b
are stowed. As angle of attack is increased above cruise values,
the air flow through the gap 5 can often cause the performance
(e.g., local drag coefficient and/or local lift coefficient) of the
local wing section proximate to the gap 5 to degrade as compared to
similar wing sections located away from the gap 5. Additionally,
because the propulsion unit 20 interferes with the installation
and/or deployment of high lift leading edge devices, the high lift
leading edge devices 12a, 12b often do not extend laterally across
the wing 10 in the area where the gap 5 is located. Accordingly,
the local wing section proximate to the gap 5 does not get the
performance benefits provided by the high lift leading edge devices
12a, 12b. Even if the high lift leading edge devices 12a, 12b
extend laterally across the gap 5, the flow interference created by
the wing 10 and the propulsion unit 20 can reduce the performance
of the local wing section proximate to the gap 5.
[0005] One approach to addressing this problem is to provide the
aircraft with a small flap-type device 30 that seals the gap when
the high lift devices 12a, 12b are deployed. In FIG. 1, the
flap-type device 30 is shown in the sealed position by dashed
lines. In the sealed position, the flap-type device 30 extends from
the bottom portion of the wing 10 and seals against a portion of
the engine housing 22. Additionally, if the housing 22 moves with
the deployment of a thrust reverser, the flap-type device 30 or a
portion of the flap-type device 30 can be configured to move with
the housing 22 to maintain the sealed position. The flap-type
device 30 can also have a retracted position in which it is
positioned proximate to the bottom of the wing 10 during cruise
when the high lift leading edge devices 12a, 12b are retracted. In
the sealed position, the flap-type device prevents air from flowing
through the gap 5, reducing drag and/or increasing a lift/drag
ratio during certain phases of flight (e.g., during takeoff). A
drawback of this arrangement is that the drag and/or lift profile
of the local portion of the wing 10 proximate to the gap 5 can
still be less than desirable for selected phases of flight
conducted with the high lift leading edge devices 12a, 12b
deployed. For example, during a landing phase of flight it can be
more desirable to increase a maximum lift coefficient than to
minimize drag, requiring a different configuration than is provided
by the flap-type device 30 in either the retracted position or the
sealed position.
SUMMARY
[0006] The present invention is directed generally toward methods
and apparatuses for controlling airflow proximate to engine
unit/airfoil systems. One aspect of the invention is directed
toward an aircraft system having an airfoil and an engine unit. The
engine unit can be at least proximate to the airfoil with a gap
between a portion of the airfoil and a portion of the engine unit.
The system can further include a flow control device proximate to
the gap and positionable among at least three stationary positions.
The three stationary positions can include a retracted position in
which the gap has a first area through which fluid can flow, a
first extended position in which the gap is at least approximately
aerodynamically sealed, and a second extended position in which the
gap has a second area through which fluid can flow. The second area
can be smaller than the first area. In further aspects of the
invention, the aircraft system can include a flow control device
having multiple flow surface sections movable relative to each
other.
[0007] Another aspect of the invention is directed toward a method
for making an aircraft system that includes installing a flow
control device at least proximate to an airfoil and an engine unit.
The method can further include coupling a control system (e.g., an
actuator and/or a computer) to the flow control device and
configuring the control system to position the flow control device
among at least three stationary positions. The three stationary
positions can include a retracted position in which a gap between a
portion of the airfoil and a portion of the engine unit has a first
area through which fluid can flow, a first extended position in
which the gap is at least approximately aerodynamically sealed, and
a second extended position in which the gap has a second area
through which fluid can flow, with the second area being smaller
than the first area.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] FIG. 1A is a partially schematic top plan view of a wing and
an engine in accordance with the prior art.
[0009] FIG. 1B is a partially schematic front elevation view of the
wing and engine shown in FIG. 1B.
[0010] FIG. 2 is a partially schematic illustration of an aircraft
system having an airfoil, an engine unit, and a flow control device
that includes a Krueger flap type device in accordance with an
embodiment of the invention.
[0011] FIG. 3A is a partially schematic top plan view of the
aircraft system shown in FIG. 2.
[0012] FIG. 3B is a partially schematic front elevation view of the
aircraft system shown in FIG. 2.
[0013] FIG. 4 is a partially schematic illustration of an aircraft
system having a flow control device that includes a variable camber
leading edge device in accordance with another embodiment of the
invention.
[0014] FIG. 5 is a partially schematic illustration of an aircraft
system having a flow control device that includes a slat in
accordance with still another embodiment of the invention.
[0015] FIG. 6 is a partially schematic illustration of a portion of
an aircraft system having a flow control device coupled to a pylon
of an engine unit in accordance with yet another embodiment of the
invention.
[0016] FIG. 7A is a partially schematic side elevation view of an
aircraft system having a flow control device coupled to a housing
of an engine unit in accordance with still another embodiment of
the invention.
[0017] FIG. 7B is a partially schematic front elevation view of the
aircraft system shown in FIG. 7A.
[0018] FIG. 8 is a partially schematic illustration of an aircraft
having an aircraft system in accordance with an embodiment of the
invention.
DETAILED DESCRIPTION
[0019] The present disclosure describes methods and apparatuses for
controlling airflow proximate to engine/airfoil systems, for
example, on aircraft having wing-mounted engine units. Several
specific details of the invention are set forth in the following
description and in FIGS. 2-8 to provide a thorough understanding of
certain embodiments of the invention. One skilled in the art,
however, will understand that the present invention may have
additional embodiments, and that other embodiments of the invention
may be practiced without several of the specific features described
below.
[0020] FIG. 2 is a partially schematic illustration of an aircraft
system 200 having an airfoil 210, an engine unit 220, and a flow
control device 230 that includes a Krueger flap type device in
accordance with an embodiment of the invention. The engine unit 220
can be located proximate to the airfoil 210 and can include an
engine 226, positioned within a housing 222, and a pylon 221. The
engine unit 220 can be coupled to the airfoil 210 via the pylon 221
and can be positioned under the airfoil 210 with a portion of the
engine unit 220 extending forward of a leading edge 211 of the
airfoil 210. This arrangement can form a gap 205 extending between
a portion of the housing 222 and a portion of the leading edge 211
of the airfoil 210. The flow control device 230 can be used to
control the fluid flow through the gap 205 to yield selected
performance characteristics from the section of the airfoil 210
proximate to the gap 205.
[0021] The flow control device 230 can be coupled to the airfoil
210 and can be positioned proximate to the gap 205. The flow
control device 230 can include multiple flow surface sections
(shown in FIG. 2 as a first section 230a and a second section 230b)
that are movable relative to each other. In other embodiments, the
flow control device 230 can have more or fewer sections, including
a single section. The flow control device 230 can also be
positionable among at least three stationary positions (e.g., the
flow control device 230 can be stopped and held in each position),
including a retracted position, a first extended position, and a
second extended position.
[0022] In FIG. 2, the flow control device 230 is shown (in solid
lines) in the first extended position so that the gap 5 between a
portion of the engine unit 220 (e.g., the housing 222) and the
airfoil 210 is at least approximately aerodynamically sealed.
Accordingly, the flow control device 230 can generally prevent
fluid flow or allow only a nominal amount of fluid flow (e.g., air)
through the gap 205. In the first extended position, the fluid flow
proximate to the flow control device 230 is forced generally upward
from the engine unit 220 and over the airfoil 210, as shown by
arrows F1 (although the fluid flow can also form vortices, as shown
by arrow F3). During certain operating conditions and/or phase(s)
of flight (e.g., takeoff), this configuration can improve the
performance characteristics (e.g., decrease the drag and/or
increase the lift/drag ratio) of the section of the airfoil
proximate to the gap 205, as compared with a system lacking the
flow control device 230.
[0023] During other operating conditions (e.g., cruise conditions),
the flow control device 230 can be positioned in the retracted
position (shown by the dashed lines in FIG. 2) in which the gap 205
has a first area through which fluid can flow. In the retracted
position, the flow control device 230 can be positioned proximate
to the lower surface of the airfoil 210 behind the leading edge 211
of the airfoil 210 to allow fluid to flow through the gap 205, as
shown by arrows F2 and F4. The fluid flow through the gap 205 can
provide a flow pattern, different from the flow pattern associated
with the first extended position, that provides a distinct set of
desired performance characteristics at selected operating
conditions and/or phase(s) of flight. For example, the retracted
position can provide a smooth flow pattern that results in low drag
during low angle of attack operations and/or high speed cruise.
[0024] The dotted lines show the flow control device 230 in a
second extended position that can provide selected performance
characteristics (e.g., an increase in maximum lift coefficient)
during other operating conditions and/or phase(s) of flights (e.g.,
landing). In the second extended position, the flow control device
230 is positioned to provide a second area through which fluid can
flow, with the second area smaller than the first area associated
with the retracted position described above. For example, the flow
control device 230 can be placed in the first extended position,
discussed above, and the second portion 230b of the flow control
device 230 can be pivoted upwardly from the housing 222 to allow
fluid flow through a portion of the gap 205. Accordingly, as fluid
approaches the gap 205, a portion of the fluid can pass through the
gap (shown by arrow F2) and a portion of the fluid can be forced
generally up and over the airfoil 210 (shown by arrow F1). The
fluid flow proximate to the gap 205 can provide a fluid flow
pattern, different from those associated with the retracted and
first extended positions, that provides a distinct set of desired
performance characteristics at selected operating conditions and/or
phase(s) of flight. For example, the second extended position can
provide a flow pattern that increases the maximum lift coefficient
of a section of the airfoil 210 proximate to the gap 205 during the
landing phase of flight.
[0025] The aircraft system 200 shown in FIG. 2 can also include a
control system 240 to position the flow control device 230 among
the at least three stationary positions. The control system 240 can
include actuators 241, signal paths 243, and a computer 245. In
FIG. 2, two actuators are shown as a first actuator 241a and a
second actuator 241b. Control systems in other embodiments can have
more or fewer actuators 241.
[0026] The first actuator 241a can include a hydraulic actuator
coupled between the airfoil 210 and the first section 230a of the
flow control device 230 and can be configured to move the flow
control device 230 between the retracted and the first extended
position. The second actuator 241b can include an electric actuator
and can be coupled between the first and second sections 230a, 230b
of the flow control device 230 to move the flow control device 230
between the first extended position and the second extended
position. For example, the second actuator 241b can move the flow
control device 230 between the first extended position and the
second extended position by moving the second section 230b of the
flow control device 230, while the first section 230a of the flow
control device 230 is held stationary by the first actuator 241a.
In certain embodiments, the first and second actuators 241a, 241b
can operate simultaneously, for example, to move the flow control
device 230 between the retracted and the first extended positions.
In other embodiments, the first and second actuators 241a, 241b can
operate sequentially.
[0027] The computer 245 can be connected to the first and second
actuators 241a, 241b by the signal paths 243 and can be programmed
to control the movement of the flow control device 230 among the
retracted, first extended, and second extended positions. In other
embodiments, more or fewer actuators 241 can be used to position
the flow control device 230, and/or the actuators 241 can be
connected to the flow control device 230 in other arrangements
(e.g., connected to different sections of the flow control device
230). In still other embodiments, the control system 240 can have
different kinds of elements and/or can transmit different kinds of
signals. For example, in certain embodiments the control system 240
can be a purely mechanical system, a purely electrical system, a
hydraulic system, or any combination thereof. In other embodiments,
the signal paths 243 can include fiber optic pathways. In yet other
embodiments of the invention, the control system 240 can direct the
flow control device 230 to move to more than three stationary
positions, providing aircraft designers with an increased
capability to tailor fluid flow patterns proximate to the gap 205
for a variety of different operating conditions.
[0028] In certain embodiments, the engine unit 220 can include a
thrust reverser 225. At least a portion of the engine housing 222
can be coupled to the thrust reverser and can be configured to move
aft when the thrust reverser is deployed, as shown by arrows T in
FIG. 2. At least a portion of the flow control device 230 (e.g., a
piece, a section, or the entire flow control device 230) can be
configured to move with the portion of the engine housing 222 when
the flow control device 230 is in the first extended position so
that the gap 205 remains at least approximately aerodynamically
sealed and/or to allow the engine housing 222 to move. In other
embodiments, the thrust reverser 225 can cause at least a portion
of the engine housing 222 to move differently (e.g., in a different
direction) and at least a portion of the flow control device 230
can be configured to move with the portion of the engine housing
222. In still other embodiments, at least a portion of the flow
control device 230 can be configured to move with the portion of
the engine housing 222 when the flow control device 230 is in the
second extended position. This feature can allow the second area
associated with the flow control device 230 being in the second
extended position (discussed above) to be held at least
approximately constant as the thrust reverser 225 causes the
housing 222 to move.
[0029] FIG. 3A is a partially schematic top plan view and FIG. 3B
is a partially schematic front elevation view of the aircraft
system 200 shown in FIG. 2 with the flow control device 230 in the
first extended position. The airfoil 210 can include at least one
leading edge device 212 laterally disposed from the flow control
device 230. In FIGS. 3A and 3B, two leading edge devices 212 are
shown as an inboard leading edge device 212a and an outboard
leading edge device 212b. In other embodiments, the airfoil 210 can
have more or fewer leading edge devices 212, including no leading
edge devices 212. In FIGS. 3A and 3B, the flow control device is
shown at least approximately aerodynamically sealed against at
least a portion of the pylon 221 and at least a portion of a
lateral edge 214 of the inboard leading edge device 212a to control
the fluid flow proximate to the gap 205. In other embodiments, the
flow control device 230 is not aerodynamically sealed against the
pylon 221 and/or the inboard leading edge device 212a to control
the fluid flow proximate to the gap 205, producing different flow
patterns than those resulting from the arrangement shown in FIGS.
3A and 3B.
[0030] In further embodiments of the invention, the airfoil 210 and
the engine unit 220 can include other arrangements and/or
components, and the gap 205 can be formed between other portions of
the airfoil 210 and the engine unit 220. For example, in certain
embodiments the engine unit 220 is not directly coupled to the
airfoil 210 (e.g., the engine unit 220 can be located proximate to
the airfoil 210, but coupled to a fuselage of the aircraft) and/or
the engine unit 220 does not extend in front of the leading edge
211 of the airfoil 210. Additionally, in some embodiments
additional structural elements associated with the airfoil 210, the
engine unit 220, a portion of the flow control device 230 (even
when in the retracted position), and/or other aircraft components
can protrude into the gap 205, even when the flow control device
230 is in the retracted position. For example, in certain
embodiments the pylon 221 can be located behind the gap 205. In
still other embodiments, the airfoil 210 and engine unit 220 can
define multiple gaps 205 (e.g., multiple gaps of varying widths
located side by side or separated by aircraft components) and/or
the system can include multiple flow control devices 230. For
example, a gap 205 and a flow control device 230 can be located
outboard of the pylon 221.
[0031] A feature of foregoing embodiments described above with
reference to FIGS. 2-3B is that the fluid flow proximate to the gap
can be controlled to affect the local lift and/or drag
characteristics of the airfoil. An advantage of this feature is
that aircraft performance can be tailored for specific phases of
flight, providing an increase in aircraft performance over that
available from current aircraft systems. Additionally, increases in
aircraft performance can reduce overall operating costs, for
example, by allowing an aircraft to carry additional weight into
and/or out of selected airfields.
[0032] In other embodiments, the flow control devices can include
other types of control surfaces. For example, FIG. 4 is a partially
schematic illustration of an aircraft system 400 having an airfoil
410, an engine unit 420, and a flow control device 430 that
includes a variable camber leading edge device in accordance with
another embodiment of the invention. The engine unit 420 can be
located proximate to the airfoil 410 with a gap 405 between a
portion of the engine unit 420 and a portion of the airfoil 410.
The flow control device 430 can be coupled to the airfoil 410 and
can be located proximate to the gap 405. The flow control device
430 can be positionable among at least three stationary positions,
including a retracted position, a first extended position, and a
second extended position. In the retracted position, shown in
dashed lines, the gap 405 can have a first area through which fluid
can flow. In the first extended position, shown in solid lines, the
gap-405 can be at least approximately aerodynamically sealed. In
the second extended position (shown in dotted lines), the gap 405
can have a second area, smaller than the first area, through which
fluid can flow. The flow control device 430 can control the airflow
proximate to the gap 405 to provide selected performance
characteristics, as discussed above with reference to FIGS.
2-3B.
[0033] FIG. 5 is a partially schematic illustration of an aircraft
system 500 having an airfoil 510, an engine unit 520, and a flow
control device 530 that includes a slat in accordance with another
embodiment of the invention. The engine unit 520 can be located
proximate to the airfoil 510 with a gap 505 between a portion of
the engine unit 520 and a portion of the airfoil 510. The flow
control device 530 can be positionable among at least three
stationary positions, including a retracted position (shown in
dashed lines), a first extended position (shown in solid lines),
and a second extended position (shown in dotted lines). In the
retracted position, the gap 505 can have a first area through which
fluid can flow. In the first extended position, the gap 505 can be
at least approximately aerodynamically sealed. In the second
extended position, the gap 505 can have a second area, smaller than
the first area, through which fluid can flow. The flow control
device 530 can control the airflow proximate to the gap 505 to
provide selected performance characteristics, as discussed above
with reference to FIGS. 2-3B.
[0034] In other embodiments, the flow control device can be coupled
to aircraft components other than the airfoil. For example, FIG. 6
is a partially schematic illustration of a portion of an aircraft
system having an airfoil 610, an engine unit 620, and a flow
control device 630 coupled to the engine unit 620 in accordance
with another embodiment of the invention. The engine unit 620 can
include a pylon 621 that couples the engine unit 620 to the airfoil
610 with a gap 605 between a portion of the engine unit 620 and a
portion of the airfoil 610. The flow control device 630 can be
coupled to the pylon 621 and can be located proximate to the gap
605. The flow control device 630 can include multiple sections,
shown in FIG. 6 as an upper section 630a and a lower section 630b.
The upper and lower sections 630a, 630b can independently rotate
forward (away from the pylon 621) and aft (toward the pylon 621)
about point A, as shown by arrows R to affect fluid flow through
the gap 605.
[0035] The flow control device 630 can be positionable among at
least three stationary positions, including a retracted position, a
first extended position, and a second extended position. In the
retracted position, the upper and lower sections 630a, 630b of the
flow control device 630 can be rotated aft and positioned proximate
to the pylon 621 so that the gap 605 has a first area through which
fluid can flow. In the first extended position, the lower and upper
sections 630a, 630b of the flow control device 630 can be rotated
forward and positioned to at least approximately aerodynamically
seal the gap 605. In the second extended position, the upper
section 630a of the flow control device 630 can be rotated forward
and the lower section 630b can be rotated aft and positioned
proximate to the pylon 621 (similar to being in the retracted
position) so that the gap 605 can have a second area, smaller than
the first area, through which fluid can flow. The flow control
device 630 can control the airflow proximate to the gap 605 to
provide selected performance characteristics, as discussed above
with reference to FIGS. 2-3B.
[0036] In other embodiments, in the second extended position the
upper section 630a of the flow control device 630 can be rotated
aft and the lower section 630b can be rotated forward. In still
other embodiments, the flow control device 630 can include more or
fewer sections and/or other arrangements (e.g., the upper and lower
sections 630a, 630b can slide laterally into and out of the pylon
621). In certain embodiments, one or both of the upper and lower
sections 630a, 630b of the flow control device 630 can also seal
against a lateral edge of a leading edge device as discussed above
with reference to FIGS. 3A and 3B.
[0037] FIG. 7A is a partially schematic side elevation view and
FIG. 7B is a partially schematic front elevation view of an
aircraft system 700 having an airfoil 710, an engine unit 720, and
a flow control device 730 coupled to the engine unit 720 in
accordance with still another embodiment of the invention. The
engine unit 720 can include a housing 722 and can be located
proximate to the airfoil 710 with a gap 705 between a portion of
the engine unit 720 and a portion of the airfoil 710. The flow
control device 730 can be coupled to the housing 722 of the engine
unit 720 and can be located proximate to the gap 705. The flow
control device 730 can include multiple sections, shown in FIGS. 7A
and 7B as a main section 730a and a vent section 730b. The vent
section 730b can be coupled to the main section 730a, and can be
configured to have at least a sealed position and an open position.
In the sealed position, the main section 730a and the vent section
730b can form a generally continuous surface that at least
restricts (and can prevent) fluid flow through the main section
730a and a vent section 730b of the flow control device 730. In the
open position, the vent section 730a can be positioned so that a
vent area allows fluid to flow through a portion of the flow
control device 730. For example, the vent section 730b can be
configured to slide inside the main section 730a to open the vent
area.
[0038] The flow control device 730 can be positionable among at
least three stationary positions, including a retracted position, a
first extended position, and a second extended position. In the
retracted position, the main and vent sections 730a, 730b of the
flow control device 730 can be rotated down about point B, as shown
by arrow D, and positioned proximate to the housing 722 of the
engine unit 720 so that the gap 705 has a first area through which
fluid can flow. In the first extended position, the main and vent
sections 730a, 730b of the flow control device 730 can be rotated
up about point B and positioned so that the main section 730a can
be at least approximately aerodynamically sealed against the
airfoil 710. Additionally, the vent section 730b can be placed in
the sealed position so that the flow control device 730 at least
approximately aerodynamically seals the gap 705. In the second
extended position, the main section 730a can be at least
approximately aerodynamically sealed against the airfoil 710 and
the vent section 730b can be placed in the open position, opening
the vent area so that the gap 705 can have a second area, smaller
than the first area, through which fluid can flow. The flow control
device 730 can control the airflow proximate to the gap 705 to
provide selected performance characteristics, as discussed above
with reference to FIGS. 2-3B.
[0039] In other embodiments, the vent area or slot created by the
vent section 730b of the flow control device 730 can be located in
other parts of the main section 730a of the flow control device 730
(e.g., closer to the airfoil 710). In still other embodiments, the
flow control device 730 can have more or fewer sections and/or
different types of sections. For example, in other embodiments, the
flow control device 730 can include a single section with multiple
positions or a flap-type device with hinged segments.
[0040] A feature of foregoing embodiments discussed above with
reference to FIGS. 4-7B is that the fluid flow proximate to the gap
can be controlled to affect the local lift and/or drag
characteristics on the airfoil. Accordingly, embodiments of the
invention discussed above with reference to FIGS. 4-7B have similar
advantages to those discussed with reference to FIGS. 2-3B. Another
feature of the foregoing embodiments discussed with reference to
FIGS. 4-7B is that the flow control device can include a wide
variety of structures and/or can be coupled to a wide variety of
components. Accordingly, the flow control device can have the
flexibility to meet a wide variety of design constraints. An
advantage of this feature is that aircraft designers can use the
flow control device to tailor aerodynamic performance for a wide
variety of configurations and/or reduce production costs for these
configurations.
[0041] FIG. 8 is a partially schematic illustration of an aircraft
850 having two aircraft systems 800, each including an airfoil 810
(e.g., a wing), an engine unit 820, and a flow control device 830
in accordance with an embodiment of the invention. Other
embodiments can have more or fewer aircraft systems 800 and/or the
aircraft systems can share common components (e.g., a computer
portion of a control system). In each aircraft system 800, the
engine unit 820 is located proximate to the airfoil 810 with a gap
805 between a portion of the airfoil 810 and a portion of the
engine unit 820. The flow control device 830 is movable to at least
three stationary positions, including a retracted position, a first
extended position, and a second extended position, similar to those
discussed above with reference to FIGS. 2-7B. In other embodiments,
the aircraft 850 can have a different airfoil 810 and engine unit
820 arrangement (e.g., an engine unit 820 depending from another
portion of the aircraft 850). In still other embodiments, the flow
control device 830 can have a different location and/or a different
arrangement (e.g., a flow control device 830 that is similar to the
flow control device discussed above with reference to FIG. 6 can be
used).
[0042] From the foregoing, it will be appreciated that specific
embodiments of the invention have been described herein for
purposes of illustration, but that various modifications may be
made without deviating from the spirit and scope of the invention.
Additionally, features described in the context of particular
embodiments can be combined or eliminated in other embodiments. For
example, in another embodiment, a flow control device can include a
first section that depends from an airfoil, similar to embodiments
discussed with reference to FIGS. 2-5, and a second section that is
coupled to an engine unit, similar to embodiments discussed with
reference to FIGS. 6-7B. Accordingly, the invention is not limited
except as by the appended claims.
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