U.S. patent application number 14/837079 was filed with the patent office on 2017-03-02 for integrated aircraft propulsion system.
The applicant listed for this patent is William B. Bryan, Richard K. Keller, Edward C. Rice. Invention is credited to William B. Bryan, Richard K. Keller, Edward C. Rice.
Application Number | 20170057649 14/837079 |
Document ID | / |
Family ID | 58103718 |
Filed Date | 2017-03-02 |
United States Patent
Application |
20170057649 |
Kind Code |
A1 |
Rice; Edward C. ; et
al. |
March 2, 2017 |
INTEGRATED AIRCRAFT PROPULSION SYSTEM
Abstract
An integrated propulsion system comprising at least two gas
turbine engines, at least one fan, and a transmission assembly
coupling the at least two gas turbine engines to the at least one
fan wherein the at least two gas turbine engines are disposed
within a main body of an airframe comprising the main body and a
pair of wings, and wherein the number of gas turbine engines is
greater than the number of fans.
Inventors: |
Rice; Edward C.;
(Indianapolis, IN) ; Keller; Richard K.;
(Indianapolis, IN) ; Bryan; William B.;
(Indianapolis, IN) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Rice; Edward C.
Keller; Richard K.
Bryan; William B. |
Indianapolis
Indianapolis
Indianapolis |
IN
IN
IN |
US
US
US |
|
|
Family ID: |
58103718 |
Appl. No.: |
14/837079 |
Filed: |
August 27, 2015 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F02K 3/12 20130101; Y02T
50/44 20130101; Y02T 50/40 20130101; B64D 27/20 20130101 |
International
Class: |
B64D 27/20 20060101
B64D027/20; B64D 33/04 20060101 B64D033/04; B64D 33/02 20060101
B64D033/02 |
Claims
1. An integrated propulsion system comprising: at least two gas
turbine engines; at least one fan; and a transmission assembly
coupling said at least two gas turbine engines to said at least one
fan; wherein said at least two gas turbine engines are disposed
within a main body of an airframe comprising said main body and a
pair of wings, and wherein the number of gas turbine engines is
greater than the number of fans.
2. The system of claim 1, each of said gas turbine engines having
an exclusive engine air flow duct comprising an engine inlet and an
engine exhaust.
3. The system of claim 2, said fan having an exclusive fan air flow
duct comprising a fan inlet and a fan exhaust.
4. The system of claim 3, wherein said fan exhaust comprises a fan
exhaust duct and a thrust vectoring mechanism.
5. The system of claim 4, wherein each of said engine inlet and
said fan inlet comprise an inlet duct extending radially outward
from said main body of the airframe.
6. The system of claim 5, wherein said at least one fan is mounted
within the main body of the airframe.
7. The system of claim 1, wherein said transmission assembly
comprises a clutch mechanism.
8. The system of claim 7, wherein output power of said at least two
gas turbine engines is distributed to said at least one fan when
said clutch mechanism is engaged.
9. The system of claim 1, said fan having a fan exhaust duct and
each of said gas turbine engines having an engine inlet duct
connected to said fan exhaust duct.
10. An integrated propulsion system consisting of: a first gas
turbine engine and a second gas turbine engine; a fan; and wherein
a transmission assembly couples said first gas turbine engine and
said second gas turbine engine to said fan.
11. The system of claim 10 wherein said first gas turbine engine,
said second gas turbine engine, and said fan each have an exclusive
air flow duct.
12. The system of claim 11 wherein the air flow duct of said fan
comprises an inlet duct, exhaust duct, and thrust vectoring
mechanism.
13. The system of claim 10 wherein each of said first gas turbine
engine, said second gas turbine engine, and said fan have an axis
of rotation which is parallel to a central axis of a main body of
an airframe.
14. The system of claim 10 wherein said first gas turbine engine
and said second gas turbine engine an axis of rotation which is
disposed at an angle to a central axis of a main body of an
airframe.
15. The system of claim 10 wherein said fan has an axis of rotation
normal to a central axis of a main body of an airframe.
16. The system of claim 10 wherein said transmission assembly
comprises a gearbox.
17. The system of claim 10 wherein said transmission assembly
comprises a clutch.
18. A method of reducing drag in a turbofan aircraft comprising:
reducing the required cross-sectional area of an aircraft body and
reducing the total weight of the aircraft propulsion system by:
disposing a first gas turbine engine on a first side of said
aircraft body and a second gas turbine engine on a second side of
said aircraft body; disposing a fan unit on said aircraft body,
said fan unit coupled to said first gas turbine engine and said
second gas turbine engine by a transmission assembly comprising a
clutch and more than one rotating linkages; venting each of said
first gas turbine engine and said second gas turbine engine via a
respective exclusive engine duct comprising an engine inlet duct
and an engine exhaust duct; and venting said fan unit via an
exclusive fan duct comprising a fan inlet duct and a fan exhaust
duct.
19. The method of claim 18 wherein said fan exhaust duct includes a
thrust vectoring mechanism.
20. The method of claim 19 wherein each of said first gas turbine
engine, said second gas turbine engine, and said fan unit have an
axis of rotation which is parallel to a central axis of a main body
of an airframe.
Description
RELATED APPLICATIONS
[0001] This application is related to concurrently filed and
co-pending applications U.S. patent application Ser. No. ______
entitled "Splayed Inlet Guide Vanes"; U.S. patent application Ser.
No. ______ entitled "Morphing Vane"; U.S. patent application Ser.
No. ______ entitled "Propulsive Force Vectoring"; U.S. patent
application Ser. No. ______ entitled "A System and Method for a
Fluidic Barrier on the Low Pressure Side of a Fan Blade"; U.S.
patent application Ser. No. ______ entitled "A System and Method
for a Fluidic Barrier from the Upstream Splitter"; U.S. patent
application Ser. No. ______ entitled "Gas Turbine Engine Having
Radially-Split Inlet Guide Vanes"; U.S. patent application Ser. No.
______ entitled "A System and Method for a Fluidic Barrier with
Vortices from the Upstream Splitter"; U.S. patent application Ser.
No. ______ entitled "A System and Method for a Fluidic Barrier from
the Leading Edge of a Fan Blade." The entirety of these
applications are incorporated herein by reference.
FIELD OF THE DISCLOSURE
[0002] The present disclosure relates generally to aircraft
propulsion, and more specifically to integrated propulsion systems
for aircraft comprising gas turbine engines and fans.
BACKGROUND
[0003] Turbofan engines provide propulsion to a wide range of
aircraft. A typical turbofan engine comprises an inlet fan, a
compressor fan, a combustor, a high-pressure turbine, and a
low-pressure turbine. Some air which passes through the inlet fan
bypasses the compressor fan, combustor, and high- and low-pressure
turbines.
[0004] In some applications, conventional turbofan engines are too
costly in terms of volume, weight, and packaging or placement
within an airframe. Due to the numerous performance requirements
and applications of modern aircraft, more efficient propulsion
systems are in demand which require less volume, weigh less, and/or
provide greater packaging and placement options within an
airframe.
[0005] The present application discloses one or more of the
features recited in the appended claims and/or the following
features which, alone or in any combination, may comprise
patentable subject matter.
[0006] According to an aspect of the present disclosure, an
integrated propulsion system comprises at least two gas turbine
engines, at least one fan, and a transmission assembly coupling the
at least two gas turbine engines to the at least one fan wherein
the at least two gas turbine engines are disposed within a main
body of an airframe comprising the main body and a pair of wings,
and wherein the number of gas turbine engines is greater than the
number of fans. In some embodiments each of the gas turbine engines
having an exclusive engine air flow duct comprising an engine inlet
and an engine exhaust. In some embodiments the fan has an exclusive
fan air flow duct comprising a fan inlet and a fan exhaust. In some
embodiments the fan exhaust comprises a fan exhaust duct and a
thrust vectoring mechanism. In some embodiments each of the engine
inlet and the fan inlet comprise an inlet duct extending radially
outward from the main body of the airframe. In some embodiments the
at least one fan is mounted within the main body of the airframe.
In some embodiments the transmission assembly comprises a clutch
mechanism. In some embodiments the output power of the at least two
gas turbine engines is distributed to the at least one fan when the
clutch mechanism is engaged. In some embodiments the fan has a fan
exhaust duct and each of the gas turbine engines having an engine
inlet duct connected to the fan exhaust duct.
[0007] According to another aspect of the present disclosure, an
integrated propulsion system consists of a first gas turbine engine
and a second gas turbine engine, a fan, and a transmission assembly
coupling the first gas turbine engine and the second gas turbine
engine to the fan. In some embodiments the first gas turbine
engine, the second gas turbine engine, and the fan each have an
exclusive air flow duct. In some embodiments the air flow duct of
the fan comprises an inlet duct, exhaust duct, and thrust vectoring
mechanism. In some embodiments of the first gas turbine engine, the
second gas turbine engine, and the fan have an axis of rotation
which is parallel to a central axis of a main body of an airframe.
In some embodiments the first gas turbine engine and the second gas
turbine engine an axis of rotation which is disposed at an angle to
a central axis of a main body of an airframe. In some embodiments
the fan has an axis of rotation normal to a central axis of a main
body of an airframe. In some embodiments the transmission assembly
comprises a gearbox. In some embodiments the transmission assembly
comprises a clutch.
[0008] According to another aspect of the present disclosure, an
integrated propulsion system comprises a first gas turbine engine
and a second gas turbine engine, each of the first gas turbine
engine and the second gas turbine engine mounted within an airframe
and having an exclusive air flow duct comprising an engine inlet
duct and an engine exhaust duct; a fan mounted to the airframe and
having an exclusive air flow duct comprising a fan inlet duct and a
fan exhaust duct; and a transmission assembly coupling the first
gas turbine engine and the second gas turbine engine to the fan;
wherein the airframe comprises a main body and a pair of laminar
flow wings and wherein the transmission assembly distributes power
from the first gas turbine engine and the second gas turbine engine
to the fan and a second load. In some embodiments the second load
is one of a lift rotor, a propeller, or a generator. In some
embodiments the fan exhaust duct comprises a thrust vectoring
mechanism.
[0009] According to yet another aspect of the present disclosure, a
method is provided of reducing drag in a turbofan aircraft. The
method comprises reducing the required cross-sectional area of an
aircraft body and reducing the total weight of the aircraft
propulsion system by: disposing a first gas turbine engine on a
first side of the aircraft body and a second gas turbine engine on
a second side of the aircraft body; disposing a fan unit on the
aircraft body, the fan unit coupled to the first gas turbine engine
and the second gas turbine engine by a transmission assembly
comprising a clutch and more than one rotating linkages; venting
each of the first gas turbine engine and the second gas turbine
engine via a respective exclusive engine duct comprising an engine
inlet duct and an engine exhaust duct; and venting the fan unit via
an exclusive fan duct comprising a fan inlet duct and a fan exhaust
duct. In some embodiments the fan exhaust duct includes a thrust
vectoring mechanism. In some embodiments each of the first gas
turbine engine, the second gas turbine engine, and the fan unit
have an axis of rotation which is parallel to a central axis of a
main body of an airframe.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] The following will be apparent from elements of the figures,
which are provided for illustrative purposes and are not
necessarily to scale.
[0011] FIG. 1 is a block schematic diagram of a typical turbofan
engine.
[0012] FIG. 2 is a block schematic diagram of a turbofan engine in
which a fan is physically separated from the engine core and linked
via transmission mechanism in accordance with some embodiments of
the present disclosure.
[0013] FIG. 3A is a block diagram of an integrated propulsion
system in accordance with some embodiments of the present
disclosure.
[0014] FIG. 3B is a detailed block diagram of the integrated
propulsion system in FIG. 3A, in accordance with some embodiments
of the present disclosure.
[0015] FIG. 4 is an isometric view of an aircraft having integrated
propulsion system in accordance with some embodiments of the
present disclosure.
[0016] FIG. 5 is a side profile view of the main body of an
aircraft in accordance with some embodiments of the present
disclosure.
[0017] FIG. 6A is a radial cross-sectional view of the main body at
the inlet ducts in accordance with some embodiments of the present
disclosure.
[0018] FIG. 6B is a radial cross-sectional view of the main body at
the engines in accordance with some embodiments of the present
disclosure.
[0019] FIG. 7A is a top cross-sectional view of the main body in
accordance with some embodiments of the present disclosure.
[0020] FIG. 7B is a top cross-sectional view of the main body in
accordance with some embodiments of the present disclosure.
[0021] FIG. 8A is a side cross-sectional view of the main body in
accordance with some embodiments of the present disclosure.
[0022] FIG. 8B is a side cross-sectional view of the main body in
accordance with some embodiments of the present disclosure.
[0023] FIG. 9A is a detailed block diagram of an integrated
propulsion system in accordance with some embodiments of the
present disclosure.
[0024] FIG. 9B is a side profile view of the main body of an
aircraft having the integrated propulsion system of FIG. 9A, in
accordance with some embodiments of the present disclosure.
[0025] While the present disclosure is susceptible to various
modifications and alternative forms, specific embodiments have been
shown by way of example in the drawings and will be described in
detail herein. It should be understood, however, that the present
disclosure is not intended to be limited to the particular forms
disclosed. Rather, the present disclosure is to cover all
modifications, equivalents, and alternatives falling within the
spirit and scope of the disclosure as defined by the appended
claims.
DETAILED DESCRIPTION
[0026] For the purposes of promoting an understanding of the
principles of the disclosure, reference will now be made to a
number of illustrative embodiments illustrated in the drawings and
specific language will be used to describe the same.
[0027] This disclosure presents embodiments to overcome the
aforementioned deficiencies of conventional turbofan engines. More
specifically, this disclosure is directed to an integrated
propulsion system having a smaller volume, lighter weight, and
greater range of placement options within an airframe when compared
to conventional turbofan engines. The integrated propulsion system
comprises gas turbine engines and at least one fan linked by a
transmission assembly.
[0028] FIG. 1 is a block schematic diagram of a typical turbofan
engine 100. The turbofan engine 100 comprises an inlet fan 101, a
compressor 103, a combustor 105, a high-pressure turbine 107, a
low-pressure turbine 109, a bypass region 111, and an exhaust
mixing region 113. The inlet fan 101 is mounted to the front of the
compressor 103. The engine core 115 is defined as the compressor
103, combustor 105, high-pressure turbine 107, and low-pressure
turbine 109.
[0029] Air enters the turbofan engine 100 via inlet fan 101. A
first portion of the air flows through the bypass region 111 and
into the exhaust mixing region 113. A second portion of the air
flows into the compressor 103 where it is pressurized, then into
the combustor where it is mixed with fuel and ignited. The ratio of
the first portion of air flowing through the bypass region 111 to
the second portion of air flowing through the engine core 115 is
referred to as the bypass ratio.
[0030] The hot, high-pressure combustion gasses are directed
sequentially into the high-pressure turbine 107 and low-pressure
turbine 109, causing each turbine 107, 109 to rotate about a shaft
which is connected to and drives the compressor 103 and the inlet
fan 101. In multiple-spool designs, more than one concentric shafts
are used to separately rotate various components. For example, in a
standard two-spool turbofan engine the high-pressure turbine 107
and compressor 103 are connected using a first common shaft while
the low-pressure turbine 109 and inlet fan 101 are connected using
a second common shaft.
[0031] In the turbofan engine 100 presented in FIG. 1, a first
portion of thrust is created by the engine 100 is created by the
inlet fan 101 sending airflow through the bypass region 111, while
a second portion of thrust is created by the exhaust of the engine
core 115.
[0032] FIG. 2 is a block schematic diagram of a turbofan engine 200
in which a fan 209 is physically separated from the engine core 115
yet linked via transmission mechanism 205. An engine inlet duct 201
and engine exhaust duct 203 are connected on either side of the
engine core 115. In some embodiments, fan 209 receives inlet
airflow with the engine inlet duct 201. In some embodiments, fan
209 sends exhaust airflow to the engine exhaust duct 203. However,
in other embodiments such as illustrated in FIGS. 4, 5, and 6 and
described below, fan 209 is connected to a fan inlet duct 405 and
fan exhaust duct 409 which are distinct from the engine inlet duct
201 and engine exhaust duct 203.
[0033] Transmission mechanism 205 transferred shaft power from
engine core 115 to fan 209. In some embodiments, transmission
mechanism 205 includes a clutch mechanism, a gearbox, a beveled
gear, and/or an angled gearbox. In those embodiments in which
transmission mechanism 205 comprises a clutch mechanism, output
power of the first engine core 115A and second engine core 115B is
distributed to the fan when the clutch mechanism is engaged.
[0034] FIG. 3A is a block diagram of an integrated propulsion
system 300 comprising a fan 209 connected to a first engine core
115A and second engine core 115B via at least one transmission
shaft 303 and a gearbox 301. In some embodiments, an additional
transmission shaft 305 is output from gearbox 301 to drive an
alternative means of propulsion.
[0035] FIG. 3B provides a more detailed block schematic diagram of
the integrated propulsion system 300. A first engine core 115A
comprises a first compressor 103A, first combustor 105A, first
high-pressure turbine 107A, and first low-pressure turbine 109A.
First engine core 115A is connected to a first engine inlet duct
201A and first engine exhaust duct 203A. A second engine core 115B
comprises a second compressor 103B, second combustor 105B, second
high-pressure turbine 107B, and second low-pressure turbine 109B.
Second engine core 115B is connected to a second engine inlet duct
201B and second engine exhaust duct 203B.
[0036] In some embodiments, as illustrated in FIG. 3B, each of
first engine core 115A and second engine core 115B have an
exclusive engine inlet duct (201A, 201B) and engine exhaust duct
(203A, 203B). In other embodiments, one or both of the engine inlet
ducts and engine exhaust ducts can be combined as a non-exclusive,
shared duct. For example first engine core 115A and second engine
core 115B will in some embodiments share a common nonexclusive
engine inlet duct while retaining separate engine exhaust ducts.
Similarly, first engine core 115A and second engine core 115B will
in some embodiments share a common nonexclusive engine inlet duct
and share a common nonexclusive engine exhaust duct. Finally, in
some embodiments first engine core 115A and second engine core 115B
will share a common nonexclusive engine exhaust duct while
retaining separate engine inlet ducts.
[0037] Fan 209 is supplied with shaft power from first engine core
115A and second engine core 115B via transmission shafts 303A,
303B, and 303C. In some embodiments, transmission shafts 303 pass
through a gearbox 301. In some embodiments, gearbox 301 further
comprises a clutch mechanism for selectively engaging transmission
shaft 303A from first engine core 115A, transmission shaft 303B
from second engine core 115B, or both. Transmission shaft 303C
couples gearbox 301 to fan 209. In some embodiments an additional
transmission shaft 305 is output from gearbox 301 to drive an
alternative load, such as an alternative means of propulsion, a
lift rotor, a propeller, or a generator.
[0038] As with the embodiment of FIG. 2 described above, in some
embodiments, fan 209 receives inlet airflow from the first engine
inlet duct 201A or second engine inlet duct 201B or a combination
of the two. In some embodiments, fan 209 sends exhaust airflow to
the first engine exhaust duct 203A or second engine exhaust duct
203B or a combination of the two. However, in other embodiments
such as illustrated in FIGS. 4, 5, and 6 and described below, fan
209 is connected to a fan inlet duct 405 which is distinct from the
first engine inlet duct 201A and second engine inlet duct 201B. Fan
209 is also connected to fan exhaust duct 409 which is distinct
from first engine exhaust duct 203A and second engine exhaust duct
203B.
[0039] The integrated propulsion system 300 illustrated in FIGS. 3A
and 3B is an improvement over a two turbofan engine configuration
because using a single fan 209 requires less volume than using two
fans, reduces overall system weight and drag, and tends to be more
fuel efficient. In some embodiments, the single fan 209 is larger
than a fan 101 mounted to a compressor 103 in a standard turbofan
engine 100.
[0040] FIG. 4 is an isometric view of an aircraft 400 having
integrated propulsion system 300. FIG. 4 illustrates a possible
placement of the integrated propulsion system 300 on a conventional
body aircraft 400. Specifically, aircraft 400 comprises a main body
401 of the airframe and a pair of laminar flow wings 403 extending
from the main body 401. This conventional body aircraft 400
contrasts with alternative aircraft bodies such as a blended wing
body or flying wing. The reduced volume of the integrated
propulsion system 300 lends itself to smaller packaging and easier
placement on a conventional body aircraft 400.
[0041] As illustrated in FIG. 4, fan 209 is contained within a fan
shroud 407 and connected to a fan inlet duct 405 and fan exhaust
duct 409 which are distinct from any engine ducting. A first engine
inlet duct 201A is shown on the side of aircraft 400.
[0042] In the illustrated embodiment, the fan inlet duct 405, fan
209, and fan exhaust duct 409 are positioned on the main body 401
above the wings 403. In some embodiments, the fan inlet duct 405,
fan 209, and fan exhaust duct 409 are positioned further forward or
further aft than the illustrated position. In some embodiments, the
fan inlet duct 405, fan 209, and fan exhaust duct 409 are more
elongated than illustrated, resulting in fan ducting which covers a
longer portion of aircraft 400. Finally, in some embodiments the
fan inlet duct 405, fan 209, and fan exhaust duct 409 are
positioned on the underside of main body 401.
[0043] Similarly, in the illustrated embodiment the first engine
inlet duct 201A is positioned on the main body 401 beneath a wing
403. In some embodiments, the first engine inlet duct 201A and
second engine inlet duct 201B (not shown in FIG. 4) are positioned
further forward or further aft than the illustrated position. In
some embodiments, engine inlet ducts 201A, 201B and engine exhaust
ducts 203A, 203B are more elongated than illustrated, resulting in
engine ducting which covers a longer portion of aircraft 400.
[0044] FIG. 5 is a side profile view of the main body 401 of the
aircraft 400, illustrating the layout of a portion of the
integrated propulsion system 300. As illustrated in FIG. 5, fan 209
is mounted within fan shroud 407 at the top of the main body 401
and connected to the fan inlet duct 405 and fan exhaust duct 409.
In some embodiments fan 209 is disposed in a recess 411 in main
body 401 to reduce aerodynamic drag. First engine core 115A is
disposed inside main body 401 and connected to first engine inlet
duct 201A and first engine exhaust duct 203A.
[0045] In some embodiments a thrust vectoring mechanism 501 is
attached to the aft portion of fan exhaust duct 409. Thrust
vectoring mechanism 501 can comprise articulating nozzles, vanes,
or paddles.
[0046] As illustrated in FIG. 5, in some embodiments fan 209 is
mounted above first engine core 115A. In some embodiments, fan 209
is mounted further forward or further aft relative to first engine
core 115A. Similarly, in some embodiments first engine core 115A is
mounted further forward or further aft relative to fan 209.
[0047] FIG. 6A is a cross-sectional view of the main body 401 at
the inlet ducts. A first engine inlet duct 201A, second engine
inlet duct 201B, and fan inlet duct 405 are each mounted radially
outward on the external main body 401 of an aircraft 400. As
discussed above, in some embodiments fan inlet duct 405 is disposed
at the top of main body 401; however, in other embodiments fan
inlet duct 405 is disposed at the bottom of main body 401.
[0048] FIG. 6B is a cross-sectional view of the main body 401 at
the engines and fan. FIG. 6B illustrates the first engine core 115A
and second engine core 115B are disposed within main body 401 of
aircraft 400. Fan 209 is disposed at the top of main body 401. In
some embodiments, fan 209 is disposed in a recess 411 in main body
401 to reduce aerodynamic drag. As discussed above, in some
embodiments fan 209 is disposed at the bottom of main body 401.
[0049] FIGS. 7A and 7B illustrate various embodiments regarding the
placement of first engine core 115A and second engine core 115B. An
airframe axis A1 extends through the center of main body 401,
parallel with the length of the exterior of main body 401. In a
first configuration 700, first engine core 115A and second engine
core 115B are disposed within main body 401 such that a first
engine core axis A2 and second engine core axis A3 are parallel to
airframe axis A1. In a second configuration 750, first engine core
115A and second engine core 115B are disposed within main body 401
such that first engine core axis A2 and second engine core axis A3
are disposed at an angle .theta.1 to airframe axis A1.
[0050] In some embodiments first engine core axis A2 and second
engine core axis A3 are defined as the axes of rotation for the
respective gas turbine engine cores.
[0051] In some embodiments, first engine core 115A and second
engine core 115B are disposed along a radial edge of main body 401.
In other embodiments, first engine core 115A and second engine core
115B are disposed radially inward from the exterior skin of main
body 401. In some embodiments, angle .theta.1 is between 5 and 25
degrees.
[0052] Similarly, FIGS. 8A and 8B illustrate various embodiments
regarding the placement of fan 209. In a first configuration 800
illustrated in FIG. 8A, fan 209 has a fan axis A4 which is parallel
to airframe axis A1. In a second configuration 850 illustrated in
FIG. 8B, fan 209 has a fan axis A4 disposed at an angle .theta.2 to
airframe axis A1. In some embodiments, angle .theta.2 is between 5
and 30 degrees. In other embodiments, angle .theta.2 is between 45
and 90 degrees. In other embodiments, fan axis A4 is normal to
airframe axis A1. In still other embodiments, angle .theta.2 is
variable based on a control system for controlling fan 209
angle.
[0053] An additional embodiment of an integrated propulsion system
900 is presented in FIGS. 9A and 9B. FIG. 9A is a detailed block
diagram of an integrated propulsion system 900, while FIG. 9B is a
side profile view of the main body of an aircraft 401 having
integrated propulsion system 900.
[0054] Integrated propulsion system 900 comprises a fan 209, first
engine core 115A, and second engine core 115B. Fan 209 is contained
within a fan shroud 407 and is connected to a fan inlet duct 405
and fan exhaust duct 409. First engine core 115A is connected to a
first engine inlet duct 201A and first engine exhaust duct 203A,
while second engine core 115B is connected to a second engine inlet
duct 203A and second engine exhaust duct 203B. As in the embodiment
illustrated in FIGS. 3A and 3B, fan 209 is coupled to first engine
core 115A and second engine core 115B via transmission shafts 303A,
303B, and 303C, and a gearbox 301. In some embodiments, an
additional transmission shaft 305 is output from gearbox 301 to
drive an alternative means of propulsion. In some embodiments a
plurality of transmission shafts are referred to collectively as a
transmission assembly.
[0055] In integrated propulsion system 900 first engine inlet duct
201A and second engine inlet duct 201B draw air from fan exhaust
duct 409. Because only a portion of fan exhaust is needed to meet
the air intake requirements of first engine core 115A and second
engine core 115B, some fan exhaust is discharged from the fan
exhaust duct 409 into the surrounding atmosphere.
[0056] The illustrated embodiment of FIGS. 9A and 9B enables first
engine core 115A and second engine core 115B to draw inlet air at a
higher pressure than atmospheric pressure, this configuration
allows first engine core 115A and second engine core 115B to
produce a higher power output and operate more efficiently. Thus
this embodiment is more similar thermodynamically to a conventional
turbofan engine than the embodiments of FIGS. 3A and 3B.
Additionally, the integrated propulsion system 900 provides
advantageous packaging of the system 900 within the main body 401
in some applications.
[0057] The disclosed integrated propulsion systems provide numerous
advantages over the prior art. The disclosed system requires a
smaller volumetric footprint within the airframe because it uses a
single fan unit vice multiple fan units or multiple turbofans. In
previous configurations which required the use of multiple fan
units a significant amount of cargo space was used by the fan
units, leading to the use of blended wing body airframes to
accommodate the configuration. In contrast, the present disclosure
is capable of use with a conventional aircraft body comprising a
main body and laminar flow wings extending from the main body. The
smaller volumetric footprint also allows for easier packaging
within the aircraft, and as a result can lead to use in a smaller
cross-sectioned aircraft. The disclosed system additionally has
improved drag performance over prior configurations (i.e. reduced
aircraft aerodynamic drag) because a single fan unit, even when
relatively larger than a fan unit of multiple fan unit
configurations, weighs less than multiple fan units and their
associated ducting. A smaller cross-sectioned aircraft would also
display improved drag performance over prior configurations.
Finally, the use of a single, larger fan unit provides greater fuel
efficiency than multiple fan configurations.
[0058] Although examples are illustrated and described herein,
embodiments are nevertheless not limited to the details shown,
since various modifications and structural changes may be made
therein by those of ordinary skill within the scope and range of
equivalents of the claims.
* * * * *