WO2021008900A1

WO2021008900A1 - Gas turbine engine

Info

Publication number: WO2021008900A1
Application number: PCT/EP2020/068818
Authority: WO
Inventors: Konstantinos Emmanouil; Robert Goulds; Vladimir Shirokov
Original assignee: Rolls-Royce Deutschland Ltd & Co Kg; Rolls-Royce Plc
Priority date: 2019-07-15
Filing date: 2020-07-03
Publication date: 2021-01-21

Abstract

The invention regards a gas turbine engine for an aircraft that comprises a nacelle (112), a fan (102), an engine core located downstream of the fan, the engine core comprising a turbine and a core shaft (111) coupling the turbine to the fan (102), an intake (101) located upstream of the fan (102), an intake centerbody (3) located upstream of the fan (102), and an accessory gearbox (4). It is provided that the accessory gearbox (4) is integrated into the intake centerbody (3).

Description

Gas turbine engine

DESCRIPTION

The present disclosure relates to a gas turbine engine.

The accessory gearbox of a gas turbine engine for an aircraft serves to drive accessories such as fuel pumps and oil pumps that are essential for the operation of the gas turbine engine. It is typically mounted as an external gearbox at the outer circumference of the engine, whereby it is coupled to a shaft such as the high-speed shaft of the turbofan engine by a separate shaft.

Document US 2010/0242496 A1 discloses a turbofan engine in which an accessory gearbox is coupled to the intermediate case of the engine.

The problem underlying the present invention is to provide for a gas turbine engine in which the accessory gearbox is arranged in an efficient manner.

This problem is solved by a gas turbine engine with the features of claim 1. Embodiments of the invention are identified in the dependent claims. According to an aspect of the invention, a gas turbine engine for an aircraft is provided that comprises a nacelle, a fan and an engine core located downstream of the fan, wherein the engine core comprises a turbine and a core shaft coupling the turbine to the fan. The gas turbine engine further comprises an intake located upstream of the fan, an intake centerbody located upstream of the fan, and an accessory gearbox.

It is provided that the accessory gearbox is integrated into the intake centerbody.

Accordingly, aspects of the present invention are based on the idea to locate the engine accessory gearbox in the intake centerbody. The intake centerbody, also referred to as intake cone or intake spike, in case of a supersonic engine serves to control the airflow into the gas turbine engine by introducing oblique and normal shock waves that slow the air down to a speed that is compatible with the gas turbine engine. The intake centerbody is a static, i.e., non-rotating element. Integrating the accessory gearbox into the intake centerbody is associated with the advantage of locating the accessory gearbox in an environment which is naturally a cool environment as it is located at the forward end of the gas turbine engine and is constantly cooled by the incoming air. Integrating the accessory gearbox into the intake centerbody is associated with the further advantage of using a volume defined by the intake centerbody that is unused in the state of the art. By integrating the accessory gearbox into the intake centerbody space is saved in another area of the gas turbine engine. Further, a radial drive shaft connecting the turbine shaft and the accessory gearbox and associated oversized bypass vanes as known in the state of the art are avoided.

A further advantage associated with the present invention lies in that it allows to locate the accessory gearbox in a position that does not affect the aero lines of the nacelle.

The intake centerbody typically comprises a wall that forms a centerbody casing and that surrounds an interior volume of the intake centerbody. According to an embodiment, the accessory gearbox is located in the interior volume of the intake centerbody. While the interior volume of the intake centerbody is typically hollow, there may be embodiments in which the interior of the intake centerbody is solid or partly solid.

According to an embodiment of the invention, the intake centerbody wall comprises vent holes configured to guide air into the interior volume, the air cooling components of the accessory gearbox. By the provision of vent holes in the wall of the intake centerbody, additional cooling can be provided for by the air extracted from the wall. Such extraction of air from the wall of the centerbody conventionally allows to control the angle of shock waves. Aspects of the present invention use such extracted air to provide for the additional function of further cooling and zone purging of the accessory gearbox.

In an embodiment of the invention, the intake centerbody is attached to a front mounting frame located upstream of the fan, the front mounting frame comprising struts connecting the frame with the nacelle. Such front mounting frame is a fixed structure located upstream of the fan.

According to an aspect of the invention, the intake is configured to extract air from the intake to the nacelle and the nacelle is configured to pass the air as tertiary flow through the nacelle, wherein air is extracted from the intake in the form of air received through the vent holes of the intake centerbody. Such air, after having cooled the accessory gearbox, is directed through the front mounting frame to the nacelle.

The struts of the front mounting frame can be further used to guide power cables, oil pipes, fuel pipes and/or other conductors to and from the accessory gearbox.

According to a further aspect of the invention, the accessory gearbox is driven directly by a fan shaft, i.e., the shaft that drives the fan. The drive is direct in that there is no reduction gearbox between the fan shaft and the accessory gearbox.

The fan shaft may be the turbine shaft of the engine core (or one of the turbine shafts of the engine core if the engine core has several turbine shafts, which is typically the case) if the turbine shaft directly drives the fan. The fan shaft may be a separate shaft if the fan is driven by the turbine shaft through a reduction gearbox, which may be the case in embodiments of the present invention.

Even though the accessory gearbox is driven directly by the fan shaft, embodiments of the invention provide for a coupling between the fan shaft and in input shaft of the accessory gearbox. In particular, according to an embodiment of the invention, the accessory gearbox input shaft is coupled to the fan shaft by at least one misalignment drive coupling, the misalignment drive coupling being configured to accommodate tolerances on the center alignment of the accessory gearbox and the engine core. Such misalignment drive coupling may be provided for, e.g., by universal joints or other flexible couplings. According to an embodiment, all units of the accessory gearbox are located in the intake centerbody. Alternatively, one or several of the units of the accessory gearbox may be located remote from the intake centerbody, such as in the nacelle. In such case, there must be provided a driving connection from the driving gear of the accessory gearbox to the units not located in the intake centerbody.

According to an embodiment, the intake centerbody comprises a forward cone that is removable to provide access to the accessory gearbox. This provides for an easy access to the accessory gearbox and allows to facilitate the replacement of accessory units or other components of the accessory gearbox. Such accessory units may include line replaceable units that are designed to be replaced quickly at an operating location.

In embodiments, the accessory gearbox is a direct drive train gearbox or epicyclic gearbox or a hypocyclic gearbox. The accessory gearbox may be of any format that suits a circular packaging envelope.

In an example embodiment, the accessory gearbox comprises a ring gear driven by the accessory gearbox input shaft, wherein the ring gear drives a plurality of accessory gears, each of the accessory gears driving an accessory unit of the accessory gearbox.

In another example embodiment, the accessory gearbox comprises a center gear driven by the accessory gearbox input shaft, wherein the center gear drives a plurality of accessory gears, each of the accessory gears driving an accessory unit of the accessory gearbox. The center gear may drive the accessory gears directly or, alternatively, with the interconnection of idler gears.

In all cases (accessory gearbox with ring gear or center gear) the rotational speed of the accessory gear depends on the transmission ratio between the different gears. By choosing an appropriate number of teeth, the rotational speed of the respective accessory gear can be adjusted in the desired manner.

According to an embodiment, the accessory units of the accessory gearbox are all located to one side of a mounting plate of the accessory gearbox. This embodiment, accordingly, provides for a single-sided mounting concept. The accessory units of the accessory gearbox may be arranged towards the upstream end of the centerbody such that they can experience efficient cooling.

According to another embodiment, the accessory gearbox comprises two mounting plates at a distance to each other, wherein some of the units of the accessory gearbox are located to one side of one of the mounting plates and the other of the units of the accessory gearbox are located to the other side of the other mounting plate. This embodiment provides for a double-sided mounting concept. It allows to mount a higher number of accessory units in the accessory gearbox.

In the embodiment in which the accessory gearbox comprises two mounting plates, the assessor gearbox may comprise a double sided ring gear driven by the accessory gearbox input shaft, wherein the double sided ring gear drives accessory gears of units of the accessory gearbox located at the two mounting plates. This provides for an effective and compact mechanism to drive accessory units of both mounting plates.

In a further embodiment, the accessory units of the accessory gearbox and/or an outer casing that may surround the accessory gearbox incorporate cooling fins to improve heat transfer. Further, the intake centerbody wall itself may incorporate cooling fins. Such cooling fins may be located at the inside of the centerbody wall in case air is extracted from the centerbody wall for additional cooling and control of shock initiation.

The accessory gearbox may include as one accessory unit a starter motor for starting the engine, wherein the starter motor drives the input shaft of the accessory gearbox. As the input shaft is coupled to the fan shaft, the starter motor can transmit a torque on the fan. The starter motor may be an air turbine starter or an electric starter/generator configured to start the engine.

The accessory units that the accessory gearbox comprises may include a fuel pump, an oil pump, a hydraulic pump and a breather. The accessory gearbox may comprise further components of an assessory gearbox. Any accessory unit that state of the art accessory gearboxes comprise may be included in the accessory gearbox integrated in the intake centerbody.

As already discussed, the gas turbine engine may be a supersonic engine, wherein the intake is a supersonic intake and the intake centerbody is an intake spike. However, in principle the invention can be implemented in any gas turbine engine in which a static (non-rotating) centerbody is provided in the engine intake.

The gas turbine engine may comprise a bypass duct located downstream of the fan, the bypass duct extending between the engine core and the nacelle and guiding a bypass airflow through the bypass duct. It should be noted that the present invention is described in terms of a cylindrical coordinate system having the coordinates x, r and cp. Here x indicates the axial direction, r the radial direction and f the angle in the circumferential direction. The axial direction is defined by the machine axis of the gas turbine engine in which the present invention is implemented, with the axial direction pointing from the engine inlet to the engine outlet. Starting from the x-axis, the radial direction points radially outwards. Terms such as "in front of" and "behind" refer to the axial direction or flow direction in the engine. Terms such as "outer" or "inner" refer to the radial direction.

The invention will be explained in more detail on the basis of exemplary embodiments with reference to the accompanying drawings in which:

Fig. 1 is a schematic sectional side view of a supersonic gas turbine engine;

Fig. 2 is a schematic sectional side view of a gas turbine engine intake that comprises a centerbody into which an accessory gearbox is integrated;

Fig. 3 the centerbody and accessory gearbox of Fig. 2, wherein a forward cone of the centerbody is removed;

Fig. 4 is a front view on the accessory gearbox of Fig. 2;

Fig. 5 shows schematically a first concept for implementing an accessory gearbox in an intake centerbody, wherein an input shaft of the accessory gearbox drives a ring gear which drives a plurality of accessory gears;

Fig. 6 shows schematically at a second concept for implementing an accessory gearbox in an intake centerbody, wherein an input shaft of the accessory gearbox drives a center gear which directly drives a plurality of accessory gears;

Fig. 7 shows schematically a third concept for implementing an accessory gearbox in an intake centerbody, wherein an input shaft of the accessory gearbox drives a center gear which, through idler gears, drives a plurality of accessory gears; Fig. 8 is a first mounting concept of an accessory gearbox integrated in an intake centerbody, wherein the accessory units of the accessory gearbox are arranged on one side of a mounting plate; and

Fig. 9 is a second mounting concept for an accessory gearbox integrated in an intake centerbody, wherein the accessory units of the accessory gearbox are arranged on opposing sides of two mounting plates.

Fig. 1 shows a turbofan engine which is intended and suitable for use in a civil or military supersonic aircraft and, accordingly, is designed for operating conditions in the subsonic, transonic and supersonic ranges.

The turbofan engine 100 comprises an engine intake 101 , a fan 102 which may be a multi-stage fan, a primary flow channel 103 which passes through a core engine, a secondary flow channel 104 which bypasses the core engine, a mixer 105 and a convergent-divergent nozzle 2 in which a thrust reverser 8 can be integrated.

The turbofan engine 100 has a machine axis or engine centerline 10. The machine axis 10 defines an axial direction of the turbofan engine. A radial direction of the turbofan engine is perpendicular to the axial direction.

The core engine comprises a compressor 106, a combustion chamber 107 and a turbine 108, 109. In the example shown, the compressor comprises a high-pressure compressor 106. A low-pressure compressor is formed by the areas close to the hub of the multi stage fan 102. The turbine behind the combustion chamber 107 comprises a high- pressure turbine 108 and a low-pressure turbine 109. The high-pressure turbine 108 drives a high-pressure shaft 1 10 which connects the high-pressure turbine 108 with the high-pressure compressor 106. The low-pressure turbine 109 drives a low-pressure shaft 1 1 1 which connects the low-pressure turbine 109 with the multi-stage fan 102. According to an alternative design, the turbofan engine may also have a medium-pressure compressor, a medium-pressure turbine and a medium-pressure shaft. Furthermore, in an alternative design it can be provided that the fan 102 is coupled to the low-pressure shaft 1 1 1 via a reduction gearbox, e.g., a planetary gearbox.

The turbofan engine is arranged in an engine nacelle 1 12. The engine nacelle 1 12 may be connected to the aircraft fuselage via a pylon. The engine intake 101 forms a supersonic air intake and is, therefore, designed and suitable for decelerating the incoming air to velocities below Ma 1 .0 (Ma = Mach number). The engine inlet is beveled in Fig. 1 , with the lower edge protruding from the upper edge, but other kinds of supersonic intakes may be implemented instead.

The flow channel through the fan 102 is divided behind the fan 102 into the primary flow channel 103 and the secondary flow channel 104. The secondary flow channel 104 is also referred to as the bypass channel.

Behind the core engine, the primary flow in the primary flow channel 103 and the secondary flow in the secondary flow channel 104 are mixed by the mixer 105. Furthermore, an outlet cone 1 13 is mounted behind the turbine in order to achieve desired cross-sections of the flow channel.

The rear area of the turbofan engine is formed by an integral nozzle 2, where the primary and secondary flows are mixed in the mixer 105 before being fed into the integral nozzle 2. The engine behind mixer 105 forms a flow channel 25, which extends through nozzle 2. Alternatively, separate nozzles can be provided for the primary flow channel 103 and the secondary flow channel 104 meaning that the flow through the secondary flow channel 104 has its own nozzle that is separate to and radially outside the core engine nozzle. One or both nozzles (whether mixed or split flow) may have a fixed or variable area.

In the context of this invention, a centerbody located in the intake 101 is of relevance. The centerbody is also referred to as center spike or inlet cone. Such centerbody is designed to control the airflow into the engine by introducing oblique and normal shock waves that slow the air down to a speed that is compatible with the engine. This allows the intake to operate properly in supersonic flight.

Fig. 2 shows a supersonic intake 101 of a gas turbine engine such as, e.g., a gas turbine engine as shown in Fig. 1 . The intake 101 is formed by the upstream part of a nacelle 1 12. The supersonic intake 101 includes a centerbody 3. The centerbody 3 is arranged rotationally symmetric along the engine axis X. It is attached to and extends from a front mounting frame 6 that is located upstream of a fan 102. The front mounting frame 6 comprises struts 61 that connect the front mounting frame 6 with the nacelle 1 12. The centerbody 3 comprises a wall 31 that forms an outer casing of the centerbody 3. The wall 31 surrounds an interior volume 32 of the centerbody 3. Inside the interior volume 32, an accessory gearbox 4 is located. The accessory gearbox 4 comprises a plurality of accessory units 41 , 42, 43. The accessory gearbox 4 is driven by an input shaft 5 which is coupled through a misalignment drive coupling 7 with a fan shaft 1 1 1 , wherein the fan shaft 1 1 1 is a low-pressure shaft which connects a low-pressure turbine with the fan 102, such as discussed with respect to Fig. 1.

Both the centerbody 3 and the accessory gearbox 4 are stationary, i.e., non-rotating. The cross-section of the centerbody 3 may be circular.

The misalignment drive coupling 7 serves to accommodate tolerances on the central alignment of the accessory gearbox 4 and the core engine. It may be implemented by one or several universal joints or in any other manner that provides for a flexible coupling.

The centerbody wall 31 comprises vent holes 34 which are depicted only schematically in Fig. 2. The vent holes may be arranged around the circumference of the wall 31 . There may be provided additional vent holes and/or the vent holes 34 may be arranged at different locations than is shown in Fig. 2.

One purpose of the vent holes 34 is to extract air from airflow A that flows into intake 101 to control the initiation of shock waves that serve to slow the air down to a speed compatible with the gas turbine engine. At the same time, the vent holes 34 serve to additionally cool the accessory gearbox 4 and its components 41 , 42, 43. Air that flows into the interior volume 32 of the intake centerbody 3 flows as airflow B through the struts 61 of front mounting frame 6 radially outward into nacelle 1 12. In nacelle 1 12, the air flows as tertiary flow C in the axial direction along the length of nacelle 1 12.

The struts 61 of the front mounting frame 6 may serve to guide power cables, oil pipes, fuel pipes, and/or other conductors to and from the accessory gearbox 4.

It is pointed out that the form of intake 101 is exemplary only and that other forms of supersonic intakes 101 may be implemented. Also, the centerbody 3 may have a different axial length and slope. Further, in embodiments, the centerbody 3 may be arranged to be movable in and against the axial direction. Fig. 3 illustrates that, in an embodiment, a forward cone 33 of the centerbody 3 is removable by movement, e.g., in the direction D (against the axial direction). By removing the forward cone 33, the accessory units 41 -43 of the accessory gearbox 4 become accessible for maintenance and possible replacement. In embodiments, some or all of the accessory units 41 -43 of the accessory gearbox 4 are modular line replaceable units and, accordingly, can be replaced quickly at an operating location. They may be sealed and contain control numbers.

Fig. 4 is a front view along the axial direction of the accessory gearbox 4. In the shown embodiment, the accessory gearbox 4 comprises five accessory units 41 -45, which are placed on a mounting plate 461 of the accessory gearbox and are oriented from the mounting plate 461 towards the upstream direction. Each of accessory units 41 , 43, 44, 45 is driven by an accessory gear that is driven by the input shaft 5, as will be explained with respect to the embodiments of Figs. 5 to 7. The accessory unit 42 located in the center of the mounting plate 461 is connected to the fan shaft 5. As will be explained with respect to Figs. 8 and 9, accessory unit 42 is a starter motor for starting the engine, the starter motor driving the input shaft 5 of the accessory gearbox 4 when in operation. Accessory units 41 , 43, 44, 45 may, e.g., be a fuel pump, an oil pump, a hydraulic pump and a breather.

Fig. 5 shows an embodiment of the accessory gearbox 4 in which the gearbox 4 comprises a ring gear 471 with internal teeth. The ring gear 471 is driven by the input shaft 5 and a rod assembly 51 connecting the input shaft 5 with the ring gear 471. Four accessory gears 481 , 483, 484, 485 are provided, each of which meshes with the internal teeth of the ring gear 471. The diameter and teeth number of the accessory gears 481 , 483, 484, 485 determines the rotational speed of the accessory gears. Each of the accessory gears 481 , 483, 484, 485 is associated with one of the accessory units 41 , 43, 44, 45 and drives the respective accessory unit.

In the embodiment of Fig. 6, the accessory gears 481 , 483, 484, 485 are driven directly by a center gear 50 connected to the input shaft 5. The center gear 50 meshes with four accessory gears 481 , 483, 484, 485 and, through the accessory gears 481 , 483, 484, 485, drives the accessory units 41 , 43, 44, 45.

Fig. 7 shows a further embodiment of the accessory gearbox 4. In the embodiment of Fig. 7, similar as in the embodiment of Fig. 6, a center gear 50 is provided which is connected to the input shaft. The center gear 50 meshes with four idler gears 49, each of which meshes with one accessory gear 481 , 483, 484, 485. This allows for a greater variation of the rotational speed of the accessory gears 481 , 483, 484, 485.

The gear trains of Figs. 5 to 7 are located inside the wall 31 of the centerbody.

Fig. 8 shows an example single-sided mounting concept of an accessory gearbox 4 integrated into an intake centerbody. The accessory gearbox 4 comprises a ring gear 471. The internal toothing of ring gear 471 meshes with the accessory gears of the accessory units, wherein the sectional view of Fig. 8 shows three accessory units 41 , 42, 43 and two accessory gears 481 , 483. Flowever, the accessory gearbox 4 may comprise further accessory units such as accessory units 44, 45 of Fig. 4. All accessory units 41 , 42, 43 are placed on a mounting plate 461 which represents a gearbox shell. The mounting plate 461 closes the cylindrical volume formed by ring gear 461 in which the accessory gears 481 , 483 are located. The accessory gears 481 , 483 are coupled to the accessory units 41 , 43 and, thereby, provide drive to the accessory units 41 , 43.

Accessory unit 42 is a starter motor which is provided to start the gas turbine engine. The starter motor 42 may be implemented as an electric starter/generator. In operation of the electric starter/generator 42, the electric starter/generator 42 drives the input shaft 5 and, accordingly, applies a torque to the fan and compressor of the gas turbine engine. The electric starter/generator 42 is directly coupled to the input shaft 5 of the accessory gearbox. As discussed with respect to Figs. 1 and 2, the accessory gearbox input shaft 5 is coupled to a fan shaft.

Fig. 9 is an example of a double-sided mounting concept of an accessory gearbox 4 integrated into an intake centerbody. The ring gear 472 that is driven by the input shaft 5 is formed as a double-sided ring gear that comprises two internal toothings spaced from each other in the axial direction. The two internal toothings may or may not have a different number of teeth. Two parallel mounting plates 461 , 462 are provided, one mounting plate 461 closing the cylindrical volume defined by the upstream part of the double-sided ring gear 472 and the other mounting plate 462 closing the cylindrical volume defined by the downstream part of the double-sided ring gear 472. Some of the accessory units 41 , 42, 43 are mounted to the upstream side of mounting plate 461 and some of the accessory units 44’, 45’ are mounted to the downstream side of mounting plate 462. The accessory units 41 , 43 are driven through accessory gears 481 , 483. The accessory units 44’, 45’ are driven by accessory gears 484’, 485’. Accessory unit 42 also in this embodiment is a starter motor which, when in operation, drives input shaft 5. The present disclosure relates to the integration of the accessory gearbox into the intake centerbody. By placing the accessory gearbox in the coolest environment of the gas turbine engine, efficient cooling of the accessory gearbox and its accessory units is provided for. In this respect, embodiments provide for an efficient heat transfer between the accessory gearbox and the wall of the centerbody such that heat of the accessory gearbox is effectively transferred to the centerbody wall which is cooled by the incoming air. To this end, for example, it may be provided for an efficient heat transfer between the mounting plate 461 or mounting plates 461 , 462 of the accessory gearbox to which the assessor units are mounted and the centerbody wall 31.

The cooling can be further improved by providing vent holes in the centerbody wall that guide air into the interior of the centerbody. Also, cooling fins may be provided on the accessory units of the accessory gearbox.

It should be understood that the above description is intended for illustrative purposes only, and is not intended to limit the scope of the present disclosure in any way. Also, those skilled in the art will appreciate that other aspects of the disclosure can be obtained from a study of the drawings, the disclosure and the appended claims. All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. Various features of the various embodiments disclosed herein can be combined in different combinations to create new embodiments within the scope of the present disclosure. In particular, the disclosure extends to and includes all combinations and sub-combinations of one or more features described herein. Any ranges given herein include any and all specific values within the range and any and all sub-ranges within the given range.

Claims

1. A gas turbine engine for an aircraft comprising:

a nacelle (1 12),

a fan (102),

an engine core (106-109) located downstream of the fan (102), the engine core comprising a turbine (109) and a core shaft (1 1 1 ) coupling the turbine (109) to the fan (102);

an intake (101 ) located upstream of the fan (102),

an intake centerbody (3) located upstream of the fan (102), and

an accessory gearbox (4), characterized in that the accessory gearbox (4) is integrated into the intake centerbody (3).

2. The gas turbine engine of claim 1 , characterized in that the intake centerbody (3) comprises a wall (31 ) surrounding an intake centerbody interior volume (32), wherein the accessory gearbox (4) is located in the intake centerbody interior volume (32).

3. The gas turbine engine of claim 2, characterized in that the intake centerbody wall (31 ) comprises vent holes (34) configured to guide air into the interior volume (32), the air cooling assessory units (41 -45) of the accessory gearbox (4).

4. The gas turbine engine of any of the preceding claims, characterized in that the intake centerbody (3) is attached to a front mounting frame (6) located upstream of the fan (102), the front mounting frame (6) comprising struts (61 ) connecting the frame (6) with the nacelle (1 12).

5. The gas turbine engine of claims 3 and 4, characterized in that air received through the vent holes (34) of the intake centerbody wall (31 ) is directed through the front mounting frame (6) to the nacelle (1 12).

6. The gas turbine engine of any of the preceding claims, as far as referring to claim 4, characterized in that power cables, oil pipes and/or other conductors are guided to and from the accessory gearbox (4) through the struts (61 ) of the front mounting frame (6).

7. The gas turbine engine of any of the preceding claims, characterized in that the accessory gearbox (4) is driven directly by a fan shaft (1 1 1 ).

8. The gas turbine engine of claim 7, characterized in that an accessory gearbox input shaft (5) is coupled to the fan shaft (1 1 1 ) by at least one misalignment drive coupling (7), the misalignment drive coupling (7) being configured to accommodate tolerances on the center alignment of the accessory gearbox (4) and the engine core.

9. The gas turbine engine of any of the preceding claims, characterized in that the all units (41 -45) of the accessory gearbox (4) are located in the intake centerbody (3).

10. The gas turbine engine of any of the preceding claims, characterized in that the intake centerbody (3) comprises a forward cone (33) that is removable to provide access to the accessory gearbox (4).

1 1. The gas turbine engine of any of the preceding claims, characterized in that the accessory gearbox (4) is a direct drive train gearbox or epicyclic gearbox or a hypocyclic gearbox.

12. The gas turbine engine of any of the preceding claims, characterized in that the accessory gearbox (4) comprises a ring gear (471 , 472) driven by the accessory gearbox input shaft (5), wherein the ring gear (471 , 472) drives a plurality of accessory gears (481 , 482, 484, 485), each of the accessory gears (481 , 482, 484, 485) driving an accessory unit (41 , 43, 44, 45) of the accessory gearbox (4).

13. The gas turbine engine of any of claims 1 to 1 1 , characterized in that the accessory gearbox (4) comprises a center gear (50) driven by the accessory gearbox input shaft (5), wherein the center gear (50) drives directly or through the interconnection of idler gears (49) a plurality of accessory gears (481 , 482, 484, 485), each of the accessory gears (481 , 482, 484, 485) driving an accessory unit (41 , 43, 44, 45) of the accessory gearbox (4).

14. The gas turbine engine of any of the preceding claims, characterized in that the accessory units (41 -45) of the accessory gearbox (4) are all located to one side of a mounting plate (461 ) of the accessory gearbox (4).

15. The gas turbine engine of any of claims 1 to 13, characterized in that the accessory gearbox (4) comprises two mounting plates (461 , 462) at an axial distance to each other, wherein some of the accessory units (41 -43) of the accessory gearbox (4) are located at one side of one of the mounting plates (461 ) and the other of the accessory units (44’, 45’) of the accessory gearbox (4) are located at the other side of the other mounting plate (462).

16. The gas turbine engine of claim 15, as far as referring to claim 12, characterized in that the accessory gearbox (4) comprises a double sided ring gear (472) driven by the accessory gearbox input shaft (5), wherein the double sided ring gear drives accessory gears of accessory units of the accessory gearbox (4) located at the two mounting plates (461 , 462).

17. The gas turbine engine of any of the preceding claims, characterized in that accessory units (41 -45) of the accessory gearbox (4) and/or an outer casing of the accessory gearbox (4) incorporate cooling fins to improve heat transfer.

18. The gas turbine engine of any of the preceding claims, characterized in that the accessory gearbox (4) includes a starter motor (42) for starting the engine, the starter motor (42) in operation driving the input shaft (5) of the accessory gearbox (4).

19. The gas turbine engine of any of the preceding claims, characterized in that the accessory gearbox (4) includes as accessory units (41 -45) at least one of a fuel pump, and oil pump, a hydraulic pump and a breather.

20. The gas turbine engine of any of the preceding claims, characterized in that the gas turbine engine is a supersonic engine, wherein the intake (101 ) is a supersonic intake and the intake centerbody (3) is an intake spike.