GB2519151A

GB2519151A - Mounting assembly

Info

Publication number: GB2519151A
Application number: GB1318105.2A
Authority: GB
Inventors: Alan Bond; Richard Varvill
Original assignee: Reaction Engines Ltd
Current assignee: Reaction Engines Ltd
Priority date: 2013-10-11
Filing date: 2013-10-11
Publication date: 2015-04-15
Also published as: GB201318105D0

Abstract

A mounting assembly for mounting a rocket nozzle 17 to allow the nozzle to pivot about a pivot or gimbal point 55. The assembly comprises a fluid duct 58 for supply of fluid to the nozzle. The duct comprises two or more flexible fluid couplings 59a, 59b which intersect a common plane 36 on which the pivot is arranged. The fluid ducts may be formed by rigid materials. A consecutive pair of flexible fluid couplings of the fluid duct may be arranged orthogonal to one another about a central axis passing through the pivot point. Additional ducts may also be provided with two or three more flexible couplings, the ducts being offset from the common plane. The flexible couplings may be configured as bellow like couplings. The flexible couplings may comprise an external, or internal, gimbal arrangement. The flexible coupling additionally comprises a plurality of spaced annular elements (70, fig. 9) connected by a partial toroid element (43).

Description

MOUNTING ASSEMBLY

The present disclosure relates to a mounting assembly for a rocket nozzle for facilitating the control of a rocket trajectory for example in a single stage to orbit (SSTO) vehicle.

The present disclosure also relates to a flexible coupling for use in such a mounting assembly. The disclosure also relates to an aircraft or aerospace vehicle including such a mounting assembly.

BACKGROUND

Typically in a rocket engine, a plurality of fluid ducts or pipes are provided in order to supply fuel and air or other oxidant to the rocket combustion chamber. However, with a large number of ducts or connections, the manoeuvràbility of a rocket nozzle associated with the rocket combustion chamber can be hindered.

The present disclosure seeks to alleviate, at least to a certain degree, the problems and/or address at least to a certain extent, the difficulties associated with the prior ad.

SUMMARY

According to a first aspect of the disclosure, there is provided a mounting assembly for mounting a rocket nozzle to allow the nozzle to pivot about a pivot or gimbal point, the assembly comprising a fluid duct for supply of fluid to said nozzle, the duct comprising two or more flexible fluid couplings which substantially intersect a common plane on which said pivot point is arranged.

Such a mounting can advantageously provide a compact fluid coupling arrangement. The fluid ducts may be formed of substantially rigid ducts to withstand high pressure gases flowing within the ducts. The flexible couplings can be relatively short in length compared with the length of the ducts, minimising sections of reduced rigidity. The arrangement of the flexible couplings intersecting a common plane can facilitate movement relative to the plane in a direction traverse to the plane, parallel to the plane or in rotation about the gimbal or pivot point in the plane. The flexible fluid couplings may be used to couple consecutive sections of the fluid duct to supply fluids, for example to a combustion chamber attached to or associated with said nozzle.

I

S

The flexible couplings may intersect the common plane by being arranged substantially on or orientated in line with or crossing or traversing the common plane. The flexible couplings may traverse the common plane orthogonally to the surface of the common plane.

Optionally,the mounting assembly is configured as a rocket nozzle mounting assembly.

Optionally, the mounting assembly may be used for non-rocket applications, where fluid couplings are provided to a pivoting body or element.

The arrangement of the flexible couplings relative to the common plane herein described are generally when the nozzles are at rest, i.e. the longitudinal and/or rotational axis of the nozzle is aligned with a gimbal axis which is perpendicular to the gimbal plane and passes through the gimbal point.

In this description, reference to a flexible coupling is also intended to cover reference to a portion of a flexible coupling.

The fluid ducts may be formed of substantially rigid materials. The ducts may be formed as pipes or channels of generally circular cross-section. The ducts may be formed of metals, for example nickel, titanium or alloys, composite materials or any other suitable material.

Optionally, the fluid duct includes portions on either side of the gimbal point on the common plane.

The flexible couplings may be formed with a generally circular cross-section. The flexible couplings may be coupled to fluid ducts using welding or other joining techniques.

The internal flow passages or longitudinal axes of the flexible couplings, optionally when unflexed, may optionally be aligned in or with the common plane, or perpendicular thereto or at least in sections or parts of the flexible couplings which traverse the common plane.

The duct between a consecutive pair or pairs of flexible couplings is optionally rigid or substantially rigid, at least relative to the flexible coupling. The ducts may comprise straight sections and/or curved sections.

Optionally, a consecutive pair or pairs of said flexible fluid couplings of a fluid duct or sections of the flexible couplings which traverse the common plane, are arranged generally orthogonal to one another about a central axis passing through said pivot point.

The duct between a consecutive pair of flexible couplings may be aligned in or parallel to the common plane.

The flexible couplings may comprise of or be formed as relatively short sections relative to the duct lengths. The flexible couplings may be arranged or configured to prevent strain being imparted by the pivoting to fluid ducts coupled to said flexible couplings.

The flexible couplings may be aligned with their flow passages in line or in plane with the common plane or perpendicular to or traversing the common plane. The flexible couplings may be configured such that they are unflexed or undeformed when the thrust trajectory of the nozzle is perpendicular to the common plane.

Additional ducts may also be provided with two or three or more flexible couplings. The flexible couplings of the additional ducts may be spaced or offset from the common plane.

Optionally, said mounting assembly comprises a further fluid duct comprising a flexible fluid coupling arranged on or traversing said common plane and in line with said pivot point or in line with a gimbal axis which passes through said pivot point and relative to which the rocket nozzle may be angled.

Optionally, said flexible couplings are configured as bellow-like couplings. The flexible couplings may be provided with an external or internal gimbal arrangement. The internal gimbal arrangement may be coupled to the flexible coupling via internal vanes.

Optionally, said mounting assembly further comprises a mounting for a rocket nozzle, the mounting being gimballed or pivotally coupled to allow rotation of the mounting about orthogonal axes on said common plane.

The mounting may comprise pairs of rotational pivots arranged as a gimbal for multi-directional movement of the nozzle about the gimbal point.

The mounting may be configured to permit angular adjustment of the nozzle by up to -It 5 degrees or up to +1-3 degrees.

Optionally, said mounting assembly further comprises one or more actuators for effecting rotation of the mounting about said orthogonal axes. The actuators may comprise hydraulic, electric or electrohydraulic actuators.

Optionally, said mounting assembly further comprises a rocket nozzle supported on said mounting, the rocket nozzle having its central longitudinal axis substantially concentric with said pivot point. At rest, the longitudinal axis of the nozzle may be aligned with the gimbal axis which passes through said gimbal point. The rocket nozzle may be sUpported along with an associated rocket combustion chamber or combustion chamber arrangement.

According to a second aspect of the disclosure, there is provided a rocket engine module comprising a plurality of mounting assemblies according to the first aspect of the disclosure with or without any optional feature thereof.

The mounting assemblies may be symmetrically arranged. Four mounting assemblies may be provided. The rocket engine module may comprise an air breathing rocket and/or a hybrid air-breathing, liquid oxygen rocket.

The rocket engine module may comprise a turbo-compressor for the compression of air and a heat exchanger for cooling said compressed air.

According to a third aspect of the disclosure, there is provided a flexible coupling, comprising a plurality of spaced annular elements, wherein connecting consecutive pairs of annular elements, a partial toroid element is provided.

Optionally, the annular elements are formed as annular rings. Optionally, the annular elements are formed of round or rounded section wire, for example wire with a substantially square cross-section with rounded corners/edges, or a wire with an oval cross section.

Optionally, the annular elements are provided as a spiral wall element.

Optionally, each partial toroid element is part of a single sheet of material.

Optionally, the wall thickness of said annular elements is greater than the wall thickness of said partial toroid element.

Optionally, the coupling is formed of a metallic material. The coupling may be formed of nickel, titanium or any suitable alloy.

Optionally, the coupling comprises fibre reinforcement.

According to a fourth aspect of the disclosure, there is provided a mounting assembly for mounting a rocket nozzle to allow the nozzle to pivot about a pivot or gimbal point, the assembly comprising a fluid duct for supply of fluid to said nozzle, the duct comprising a flexible fluid coupling arranged on the pivot point and/or traversing a common plane in line with said pivot point. Optionally, the flexible coupling is in line with a gimbal axis which passes through said gimbal point and relative to which the rocket nozzle can be angled.

According to a fifth aspect of the disclosure, there is provided a vehicle, an aircraft or aerospace vehicle comprising a mounting assembly according to the first or fourth aspect, and/or a rocket engine module according to the second aspect and/or a flexible coupling according to the third aspect with or without any optional feature thereof.

BRIEF DESCRIPTION OF THE DRAWINGS

The present disclosure may be carried out in various ways and embodiments of the disclosure will now be described by way of example with reference to the accompanying drawings, in which: Figures IA, lB and IC show side, plan and rear elevations respectively of a single stage to orbit (SSTO) aircraft; Figure 2 shows a cross-section through a nacelle containing a rocket engine Figure 3a shows a schematic side view of a ràèket nozzle with a flexible coupling provided concentric with the axis of the nozzle; Figure 3b shows an end on view of the arrangement shown in Figure 3a; Figure 4a shows a schematic side view of a rocket nozzle with a fluid conduit provided with two flexible couplings; Figure 4b shows an end on view of the arrangement shown in Figure 4a; Figure 5a shows a schematic side view of a rocket nozzle with a fluid conduit with three flexible couplings; Figure Sb shows an end on view of the arrangement shown in Figure 5a; Figure 6a shows a schematic end of a rocket nozzle with a fluid conduit with two flexible couplings; Figure 6b shows a side view of the arrangement as shown in Figure 6a; Figure 7a shows a schematic end of a rocket nozzle with a fluid conduit with two flexible couplings; Figure 7b shows a side view of the arrangement as shown in Figure 7a; Figure 8 shows a cross-section through a flexible fluid coupling; Figure 9 shows a partial cross-section through an alternative flexible fluid coupling; Figure ba shows a schematic view an actuator arrangement for controlling the angle of a rocket nozzle; and Figure lOb shows a plan view in the direction of the nozzle outlet of Figure ba.

DETAILED DESCIPTION

Figures 1A, IB, and IC show a single stage to orbit (SSTO) aircraft 1 with a retractable undercarriage 2, 3, 4, having a fuselage 5 with fuel and oxidant stores 6, 7 and a payload region 8. A tail fin arrangement 9 and canard arrangement 10 are attached to the fuselage 5. Main wings 13 with ailerons 14 are attached to either side of the fuselage 5 and each wing 13 has an engine module 15 attached to a wing tip 16 thereof. As shown in Figures IC and 2, the rear of each engine module 15 is provided with four rocket nozzles 17 surrounded by various bypass burners 18.

Figure 2 shows an engine module contained within a nacelle 20, which may be attached to an aircraft wing, such as an aircraft wing 13 of an aircraft 1 as shown in Figures 1A, lB andiC.

The engine module 15 includes air inlet 19, heat exchanger 21, turbo-compressor 22 and a plurality of fluid flow conduits or channels 23 for the supply of fluid, such as fuel/oxidant to combustion chambers associated with rocket nozzles 17a, 17b.

During operation of the engine module 15, part of the incoming air passing through the air inlet 19 passes through the heat exchanger 21 to the turbo compressor 22 and another part is bypassed along bypass duct 19a to the bypass burners 18. These bypass burners 18 can provide additional thrust to the thrust provided through the main rocket nozzles 17.

The rocket nozzles 17a, 17b may provide thrust through the combustion of fuel with an oxidant in a rocket combustion chamber 52a, 52b associated with each nozzle 17a, 17b.

The fuel may, for example, be hydrogen fuel. The oxidant may comprise air which has passed through the turbo-compressor 22 and/or may comprise liquid oxygen from an on-board liquid oxygen store.

It will be understood that the engine module may be replaced with other types of engine module and that the mounting arrangement described in this disclosure may be equally applied to different engine configurations.

In the engine module as shown in schematic cross-section in Figure 2, air passes from the turbo compressor 22 through a central main air flow duct 27 which splits into divergent ducts 24a, 24b to deliver air to combustion chambers 52a, 52b associated with each of the rocket nozzles 17a, 17b. Although only two rocket nozzles 17a, 17b are shown in Figure 2, it should be understood that any number of rocket nozzles may be chosen depending on the thrust required and the packaging constraints of the vehicle.

Each of the divergent air ducts 24a, 24b diverge at an angle to a centre line passing through the main inlet air duct 27. The ducts 24a, 24b extend partially radially and partially axially with the distal end of each duct (i.e. the end furthest from the main air flow duct 27) in alignment with the central rotational axis of a respective rocket nozzle I 7a, I 7b.

The air ducts 24a, 24b are coupled to the combustion chamber 52a, 52b of the respective rocket nozzle 17a, 17b.

Fuel is delivered to the rocket chambers 52a, 52b of tile nozzles I 7a, I 7b via ducts 29a, 29b using pump 26.

The ducts shown in Figure 2 may be coupled to the rocket combustion chambers or nozzles using one or more of the coupling arrangements shown in Figures 3a to 7b and described below.

Figure 3a shows a side view of a rocket nozzle 17, which is gimballed about a pivot or gimbal point 55. The pivot or gimbal 55 may permit pivoting, or rotation of the nozzle about one or more axes. In the embodiment, the nozzle may pivot about two orthogonal axes z, y.

The degree of movement permitted will depend on application. In the embodiment, the degree of movement or pivoting angle, e, may be of the order +1-3 degrees relative to the gimbal axis x. Each nozzle'may be provided on a mounting which allows for the pivoting or gimballing of each nozzle.

The orientation of each nozzle may be adjusted in order to control the trajectory of the aircraft to'which the engine module is attached. Actuators (not shown) may be provided in order to control the degree of movement of the nozzles.

In the embodiment, the rocket combustion chamber/nozzle 17 is supplied with air or other fluid via duct 56. A flexible coupling 57 is provided to couple the duct 56 to the combustion chamber/nozzle arrangement 17. The flexible coupling 57 intersects a common or gimbal plane 36, by crossing or traversing said gimbal plane 36, which is a plane passing through the pivot or gimbal point 55 and perpendicular to gimbal axis x relative to which the nozzle can beangled.

The flexible coupling 57 is arranged concentric on the gimbal axis x at the point the coupling traverses the gimbal plane. The gimbal axis is an axis passing through the gimbal point and perpendicular to the gimbal plane 36.

The flexible coupling 57 provides a compliant coupling to permit pivoting of the nozzle/combustion chamber assembly 17 about the pivot point 55. With such an arrangement with the coupling 57 on the gimbal axis, x, only a single flexible coupling 57 is required. The flexible coupling may be a bellow type connection.

The arrangement as shown in Figure 3a, 3b has the.plvantage that the axial thrust load on the gimbal 55 is reduced as it is offset by the axial air or fluid pressure load in the flexible coupling 57. In addition, the arrangement is also more compact than the arrangements shown in 4a, 4b, 5a, 5b and is therefore most suited to the largest diameter pipe crossing the gimbal plane.

Figure 4a shows a side view of a rocket combustion chamber/nozzle assembly 17 which is supplied with fluid from duct 58. The duct 58 may, for example, supply cooling medium to the rocket nozzle skirt. The duct 58 may be provided in additional to the duct 56 shown in Figure 3a for example where multiple fluid connections to the rocket nozzle/chamber are required.

As shown in Figure 4b, the dud 58 is provided with two flexible couplings 59a, 59b which intersect the gimbal plane by being aligned in the gimbal plane 36. The two flexible couplings 59a, 59b or at least a portion thereof are positioned or arranged orthogonal to one another about the gimbal point 55.

The flexible couplings 59a, 59b are arranged substantially in alignment on the common plane 36, which, when the nozzles 17 are at rest, i.e. with no pivoting, is perpendicular to the gimbal axis, x. In the embodiment, the gimbal axis, x, is also the longitudinal rotational axis of the rocket nozzle 17, when the nozzle is at rest.

By providing each of the fluid ducts with a flexible coupling substantially intersecting, in the embodiment, by being aligned on or traversing the common plane 36, any possible strain imparted on the fluid supply ducts 24a, 24b, 28a, 28b as the nozzles pivot can be better controlled or reduced.

Fig 5a shows how ducts can be coupled to the combustion chamber/rocket nozzle assembly 17 if the flexible couplings cannot be provided on the gimbal plane 36. Here, the duct 60 comprises three flexible couplings 63a, 63b, 63c as shown in Figure Sb. The flexible couplings 63a, 63b, 63c are offset from the gimbal plane 36. The duct 60 can cope with fore/aft movement, b, of the duct pipe work. The ghost line 64 shows the movement of the duct 60, such that flexible coupling 63c is offset to position 62b at a distance, b, from its Original position 62a, while flexible coupling 63a remains substantially in its original position 61a.

Figure 6a shows an end view of a rocket combustion.;chamber/nozzle assembly 17 which is supplied with fluid from a propellant source represented by cylinder 71.

The fluid is supplied via a duct comprising three sections 72a, 72b, 72c. Between the first section 72a and the second section 72b of the duct, a flexible coupling 73a is provided.

Between the second section 72b and the third section 72c of the duct, a further flexible coupling 73b is provided. The duct sections are substantially rigid.

As shown in Figure 6a, the flexible couplings or at least a portion thereof are arranged or positioned orthogonal to one another about a gimbal point 55 which is in alignment with the central longitudinal axis X of the rocket nozzle. The second section 72b of duct follows a curve with its centre of curvature on the gimbal point 55. In the embodiment, the flexible couplings 73a, 73b are arranged offset and substantially equidistant from the gimbal axis x in directions perpendicular therefrom.

As shown in Figure 6b, the first and the second flexible couplings 73a, 73b are aligned so as to intersect the plane 36 by crossing or traversing the gimbal plane 36. The propellant source, in the embodiment, is arranged offset from the gimbal plane 36 in the direction of the open end of the nozzle 17.

The flexible couplings 73a, 73b are arranged crossing or traversing the common plane 36, which, when the nozzle 17 is at rest, i.e. with no pivoting, is perpendicular to the gimbal axis, x. In the embodiment, the gimbal axis, x, is also the tongitudinal rotational axis of the rocket nozzle 17.

By providing the fluid duct with flexible couplings substantially aligned on or traversing the common plane 36, any possible strain imparted on the fluid supply ducts 72a, 72b, 72c as the nozzles pivot can be better controlled or reduced.

Figure 7a shows an end view of a rocket combustion chamber/nozzle assembly 17 which is supplied with fluid from a propellant source represented by cylinder 71.

The fluid is supplied via a duct comprising three sections 74a, 74b, 74c. Between the first section 74a and the second section 74b of the duct, a flexible coupling 75a is provided.

Between the second section 74b and the third section 74c of the duct, a further flexible coupling 75b is provided.

As shown in Figure 7a, the flexible couplings or at laat a portion thereof are arranged or positioned orthogonal to one another about a gimbal point 55 which is in alignment with the central longitudinal axis X of the rocket nozzle. The second section 74b of the duct has a main straight section arranged substantially parallel to the gimbal plane 36 and slopes or leans towards the gimbal axis X away from the propellant source 71. The first and second flexible couplings are thus arranged at different distances from the gimbal point 55 or axis X. As shown in Figure 7b, the first and the second flexible couplings 75a, 75b are aligned so as to cross or traverse the gimbal plane 36. The propellant source, in the embodiment, is arranged offset from the gimbal plane 36 in the direction of the open end of the nozzle 17.

The flexible couplings 75a, 75b are arranged substantially to cross or traverse the gimbal plane 36, which, when the nozzle 17 is at rest, i.e. with no pivoting, is perpendicular to the gimbal axis, x. In the embodiment, the gimbal axis, x, is also the longitudinal rotational axis of the rocket nozzle 17.

By providing the fluid duct with flexible couplings substantially aligned on or traversing the common plane 36, any possible strain imparted on the fluid supply ducts 74a, 74b, 74c as the nozzles pivot can be better controlled or reduced.

Figure 8 shows a cross-section of a flexible coupling in the form of a bellows-like connection 42. The cross section comprises a plurality of spaced annular sections 51 or rings of radius R. Consecutive or successive pairs of annular sections 51 are joined via split or partial toroid sections 43 which extend radially from the edges of the annular sections 49, 51 with the toroid centre of each toroid section being spaced a distance, a, from the rotational centreline (CL) of the coupling. Each partial toroid 43 is formed of radius, b, about said toroid centre. The wall thickness, t of the spilt toroid parts is less than the wall thickness, t of the narrow annular sections.

The pipe pressure hoop loads are carried by the narrow annular sections 49, 51 in the flexible coupling 42. These annular sections are resistant to flex when the bellow connection is bent. Annular sections could be formed of a metal material, such as nickel or titanium or any suitable alloys, and could be additionally fibre reinforced or formed of composite materials. The flexible couplings can be configured to withstand the high fluid pressures being carried in the ducts to the rocket combustion chambers.

Bending of the flexible connection is enabled by the split toroids 43, which elastically deform. The split toroid sections 43 can be manufactured in extremely thin material due to their small internal radius. This construction means that the pressure load (pipe hoop) carrying material and the bending material have distinct separate roles, and can be formed of suitable, possibly distinct and different, materials accordingly.

The pipe axial loads are carried by an external or internal gimbal arrangement 65 coupled to the pipe walls via vanes 66a, 66b, See, 66d.

As an alternative to the annular rings 51, a thick walled spiral could be used instead. The spiral may carry the pipe hoop burst loads, but may have greater stiffness to carry its own weight and prevent flow induced vibrations. The partial toroids could be formed substantially the same as shown in Figure 8.

A further embodiment of a flexible coupling is shown in Figure 9. Instead of the annular rings, round section wire 70 may be used to reinforce the coupling. The partial toroids 43, which are thin walled, may be hydroformed from a single sheet of material. This can serve to reduce the difficulty in effecting a pressure-tight join with the annular rings as shown in Figure 8.

Figure ba shows a schematic representation of a rocket nozzle 17 and actuator 44 which includes actuator piston 45. The actuator may be provided as a hydraulic, electric or electro-hydraulic unit that can be used to vary the degree of movement of the rocket nozzle about the gimbal point 47, which lies on the gimbal plane 36 as shown in Figures 3a to Sb.

The gimbal point 47 is a point about which the rocket nozzle 17 may pivot. The actuator 44 is connected via the piston 45 to a mounting 46 which is used to support the nozzle 17.

In the example, each nozzle is provided with two actuators, acting parallel to the rocket chamber axis, but positioned orthogonally to one another. This gives rotation about both Y and Z axes as shown in Figure 11 b. As shown in Figure 1 Ob, a first actuator is shown in tine with axis ZZ and second actuator 48 is provided in line with axis YY.

The arrangement of ducts and flexible connections can provide for a compact design of the mounting assembly and can facilitate the movement of the rocket nozzles in order to control the trajectory of a rocket powered vehicle.

Various modifications may be made to the described embodiments without departing from the scope of the invention as defined in the accompanying claims.

Claims

CLAIMS1. A mounting assembly for mounting a rocket nozzle to allow the nozzle to pivot about a pivot or gimbal point, the assembly comprising a fluid duct for supply of fluid to said nozzle, the duct comprising two or more flexible fluid couplings which substantially intersect a common plane on which said pivot point is arranged.
2. A mounting assembly as claimed in claim 1, wherein the flexible couplings intersect the common plane by being arranged substantially on or orientated in line with or crossing or traversing the common plane.
3. A mounting assembly as claimed in claim I or 2, wherein the flexible couplings traverse the common plane orthogonally to theurface of the common plane.
4. A mounting assembly as claimed in any one of the preceding claims, wherein the mounting assembly is configured as a rocket nozzle mounting assembly.
5. A mounting assembly as claimed in any one of the preceding claims, wherein the fluid ducts are formed of substantially rigid materials.
6. A mounting assembly as claimed in any one of the preceding claims, wherein the internal flow passages or longitudinal axes of the flexible couplings, may be aligned in or with the common plane, or perpendicular thereto or at least in sections of the flexible couplings which intersect the common plane.
7. A mounting assembly as claimed in any one of the preceding claims, wherein a consecutive pair or pairs of said flexible fluid couplings of a fluid duct are arranged or positioned generally orthogonal to one another about a central axis passing through said pivot point..
8. A mounting assembly as claimed in any one of the preceding claims, wherein a duct between a consecutive pair of flexible couplings may be aligned in or parallel to the common plane.
9. A mounting assembly as claimed in any one of the preceding claims, wherein additional ducts may also be provided with two or three or more flexible couplings and arranged spaced or offset from the common plane.
10. A mounting assembly as claimed in any one of the preceding claims, wherein said mounting assembly comprises a further fluid duct comprising a flexible fluid coupling arranged on or traversing said common plane and in line with said pivot point.
11. A mounting assembly as claimed in any one of the preceding claims, wherein said flexible couplings are configured as bellow-like couplings.
12. A mounting assembly as claimed in any one of the preceding claims, wherein the flexible couplings may be provided with an external or internal gimbal arrangement.
13. A mounting assembly as claimed in any one of the preceding claims, wherein said mounting assembly further comprises a mounting for a rocket nozzle, the mounting being gimballed or pivotally coupled to allow rotation of the mounting about orthogonal axes on said common plane.
14. A mounting assembly as claimed in claim 13, wherein the mounting for the rocket nozzle may be configured to permit angular adjustment of the nozzle by up to -1+ 5 degrees or +1-3 degrees relative to a gimbal axis.
15. A mounting assembly as claimed in claim 13 or 14, wherein said mounting assembly further comprises one or more actuators for effecting rotation of the mounting about said orthogonal axes.
16. A mounting assembly as claimed in any one of the preceding claims, wherein said mounting assembly further comprises a rocket nozzle supported on said mounting, the rocket nozzle having its central longitudinal axis substantially concentric with said pivot point.
17. A rocket engine module comprising a plurality of mounting assemblies according to any one of claims Ito 16.
16. A flexible coupling, comprising a plurality of spaced annular elements, wherein connecting consecutive pairs of annular elements, a partial toroid element is provided. / /
19. A flexible coupling according to claim 18, wherein the annular elements are formed as annular rings.
20. A flexible coupling as claimed in claim 18, wherein the annular elements are formed of round or rounded section wire.
21. A flexible coupling as claimed in claim 18, wherein the annular elements are provided as a spiral wall element.
22. A flexible coupling as claimed in any one of claims 18 to 21, wherein each partial toroid element is part of a single sheet of material.
23. A flexible coupling as claimed in any one of claims 18 to 22, wherein the coupling is formed of a metallic material.
24. A flexible coupling as claimed in any one of claims l8to 23, wherein the coupling comprises fibre reinforcement.
25. A mounting assembly for mounting a rocket nozzle to allow the nozzle to pivot about a pivot or gimbal point, the assembly comprising a fluid duct for supply of fluid to said nozzle, the duct comprising a flexible fluid coupling arranged on the pivot point and/or traversing a common plane in line with said pivot point.
26. A mounting assembly as claimed in claim 25, wherein the flexible coupling is in line with a gimbal or pivot axis which passes through said gimbal point and relative to which the rocket nOzzle can be angled.
27. An aircraft, vehicle or aerospace vehicle comprising a mounting assembly as claimed in any one of claims ito 16 or 25 and 26 and/or a rocket engine module as claimed in claim 17 and/or a flexible coupling as claimed in any of claims 18 to 24.
26. A mounting assembly substantially as described herein with reference to the accompanying drawings.
29. A rocket engine module substantially as described herein with reference to the accompanying drawings. * 15
30. A flexible coupling substantially as described herewith with reference to the accompanying drawings.
31. A vehicle, aircraft or aerospace vehicle substantially as described herein with reference to the accompanying drawings.