GB2396387A

GB2396387A - Air intake closure mechanism with lever and spring mechanism

Info

Publication number: GB2396387A
Application number: GB0326401A
Authority: GB
Inventors: Herbert Engel
Original assignee: EADS Astrium GmbH; EADS Space Transportation GmbH
Current assignee: EADS Space Transportation GmbH
Priority date: 2002-11-15
Filing date: 2003-11-12
Publication date: 2004-06-23
Anticipated expiration: 2023-11-12
Also published as: GB2396387B; FR2847306A1; DE10253579A1; GB0326401D0

Abstract

An air intake arrangement 1 for an air duct 20 of air-breathing engines, in particular ram jet and ram jet rocket engines. A closure shutter 10 acts to seal the opening of air duct 20, and has front region 11, and rear region 12. The front region 11 is attached to articulation point 25 of air duct 20 via spring 30, and rear region 12 is connected to air duct 20 by pivoting and displacing means 31, 32, 33. The rear region 12 is preferably guided by means 15 abutting member 34. Articulation point 31 is preferably displaceable via sliding carriage 50, whose position is fixedly releaseable by blocking device 80. Movement of the sliding carriage 50 to open the closure 10 simultaneously releases sal element 70 and hence opening duct 60 for directing away the boundary layer. A method is also claimed for assembling the air intake 1 outside of the air duct 20, prior to insertion therein.

Description

( I I 1 2396387

Air Intake for Engines and Manufacture Thereof The invention relates to an air intake for an air duct of air-breathing engines, in particular ram jet engines or ram jet rocket engines of flying objects for supersonic 5 flight speed, having an intake contour, an inner closure shutter which covers the intake contour and which, when viewed in the direction of flow, comprises a front region and a rear region, and having an actuation mechanism for opening the closure shutter.

Ram jet engines or ram jet rocket engines are used, inter alla, for flying objects which 10 can be carried and launched by carrier aircraft. The closure shutter in front of the air intake prevents the diffuser boom during supersonic carrier and booster flight and the introduction of foreign bodies. The closure shutter further protects the scarfed and

sensitive front intake edges of the air intake to the greatest possible extent from erosion during carrier flight and against being dented owing to improper handling, for example, 15 during transport. Furthermore, the covering by the closure shutter allows for low flow resistance during carrier and booster flight.

DE 196 51 491 A 1 discloses an air intake for an air duct having an inner closure shutter which covers the intake contour of the air duct wherein the one-piece closure shutter is 20 conformed so that it covers the front edges in the closed position and is opened by means of an actuation mechanism.

This actuation mechanism comprises a guiding ramp, along which the rear region of the closure shutter, when viewed in the direction of flow, slides into the open position 25 owing to the aerodynamic forces which occur. The front region of the closure shutter, when viewed in the direction of flow, is at the same time pulled towards the rear by means of a sliding carriage which is fitted to the upper side of the air intake. The movement of the rear region can be supported and damped by means of tension springs and damping piston systems.

l Such a closure system for an air intake has the disadvantage that the closure shutter can become wedged during opening owing to the imprecise guiding using the proposed actuation mechanism and a rapid and complete opening of the closure shutter within a few milliseconds when the operating Mach number is reached cannot be ensured.

The object of the invention is therefore to further develop an air intake for an air duct of air-breathing engines having a closure shutter so that the closure shutter can be opened in a defined manner within a few milliseconds with no danger of the closure shutter becoming wedged or jammed at given wind loads. However, the closure shutter should 10 also continue to prevent the introduction of foreign bodies into the air intake during

supersonic flight and booster flight, protect the scarfed and sensitive front edges of the air intake against erosion and denting and further have low flow resistance during carrier and booster flight. Furthermore, a method of manufacturing an air intake of this type having a closure shutter is to be set out.

In order to achieve the object relating to the air intake having a closure shutter, an air intake of the type described in the introduction is characterized according to the

invention in that the actuation mechanism comprises a spring device which is articulated between the front region of the closure shutter and the air duct and means 20 articulated to the rear region of the closure shutter for pivoting and displacing the rear region of the closure shutter.

Owing to the spring device, which is articulated between the front region and the air duct and which can, in the simplest case, be a helical spring or another spring 25 arrangement which is provided with energy in the tensioned state, and the force which is applied thereby, the front region of the closure shutter is pulled in the direction of force when the opening operation is activated and carries out a defined movement in the direction of force. Furthermore, the rear region of the closure shutter is pivoted and displaced in a defined manner from the closed position into the open position using 30 appropriate means. Both regions of the closure shutter are thus guided from one position to the other and are not permitted to move freely, thus rendering wedging or jamming impossible. Owing to the system of the internal closure shutter having a spring

device at the front region of the shutter and the means for displacing and pivoting the rear region of the closure shutter, however, it is also possible to prevent foreign bodies from being introduced into the air duct during supersonic flight and booster flight and to protect the scarfed and sensitive front edges of the air intake against erosion and 5 denting. Furthermore, the arrangement according to the invention offers low air-flow resistance during carrier and booster flight.

In order to move the closure shutter from the closed position into the open position, it is possible to use driving means of any type, such as motors, additional springs or the like, 10 from the prior art relating to drives, but the spring device is advantageously fitted

between the front region of the closure shutter and the air duct in such a manner that the energy stored therein serves to displace the closure shutter when the opening operation is activated. Alternatively or additionally, it is also possible for the aerodynamic forces acting on the closure shutter during flight to be used to produce a force necessary for 15 the displacement. It is thereby possible to carry out the movement of the closure shutter with no additional constructional complexity and using only the means available, which leads to a saving in terms of components and manufacturing costs.

The means for displacing and pivoting the rear region of the closure shutter are 20 preferably in the form of levers which can be displaced in a linear manner in the direction of flow. The rear region of the closure shutter is in particular preferably operatively connected to the air duct at a displaceable articulation point by means of a lever which is rotatably articulated to the closure shutter and which is in turn rotatably articulated to an extension arm. Constructions of this type are simple to manufacture 25 and handle and carry out the required movement sequences in an extremely precise manner. The rear region of the closure shutter is advantageously guided by means of a formed member of the air intake, which member is in the form of a control cam. To this end, 30 the closure shutter has a control region which is fixedly connected thereto and which travels over the formed member during the movement of the rear region of the closure

shutter. In a particularly advantageous manner, the control region is a simple extension arm which is articulated to the closure shutter in a rigid manner.

Owing to the control region which abuts the formed member and which travels over the 5 control cam, the movement of the rear region of the closure shutter is further fixed and specified, with the result that any incorrect movements, which might still possibly occur via the spring device or the pivoting and displacing means, are completely eliminated by the additional guiding action.

10 There are many different methods of bringing about the release of the linear movement during the movement sequence of the rear region of the closure shutter. For instance, it is possible for locking arrangements to be released, but a sliding carriage, which is fixed by a blocking device during supersonic carrier and booster flight, preferably allows the rear region of the closure shutter to be displaced and consequently the 15 closure shutter to be opened when the blocking device is released.

This is a very simple procedure, in particular when the spring device and/or the aerodynamic forces cause a constant force to act on the closure shutter and a defined and precise starting point can thus be provided for the opening operation. However, 20 even when the opening of the closure shutter is to be carried out in a different manner, a definite activation is thereby ensured. Furthermore, owing to the low constructional height, a closure using a sliding carriage can be readily fitted and introduced anywhere without the function of the components present being impaired. Furthermore, the blocking or activation device can be fitted remote from the operational region, where 25 the constructional height or space is available therefor.

The blocking device can be constructed in many different manners according to known possibilities from the prior art, but it is preferably a dual-security system which

particularly preferably comprises a locking bolt which directly releases the sliding 30 carriage and which can be moved by means of a lifting piston. To this end, the lifting piston is located in a pressure cylinder and is fixed there relative to the working stroke thereof by means of a securing bolt. When pressure is applied by the pressure cylinder,

the securing bolt moves backwards and releases the lifting piston which then carries out its working stroke and moves the locking bolt, which results in the sliding carriage being displaceable. This blocking device has the advantage that the dual-security means having the secured lifting piston are secured against inadvertent release but can be 5 safely and quickly released with the application of pressure.

The air flow close to the wall (boundary layer) is disturbed owing to the viscosity of the air, which leads to a reduction in the efficiency of the air guiding system. In order to compensate for this, the boundary layer can be directed outwardly away. When the air 10 intake has an air discharge duct for directing away the boundary layer, this should also be closed during supersonic carrier or booster flight in order to protect against contamination or mechanical damage. When the closure shutter is opened, this protection means should then also be opened as quickly as possible which can be carried out by means of a separate opening device but which is preferably brought about 15 by the sliding carriage releasing the air discharge duct at the same time when displaced.

In this manner, one component is used for several functions, which leads to savings and ensures precise simultaneity.

The air discharge duct in the closed state is in particular preferably closed by means of a 20 sealing element, which is held in the blocked state by the sliding carriage, is released by the sliding carriage being displaced and is expelled by the incoming flow of air. The advantage of such a form of closure for the air discharge duct lies in the fact that the sliding carriage has to carry out only a small positioning movement relative to the width of the air discharge duct and does not have to be moved over the entire width of the 25 opening. It is sufficient to travel only the positioning distance which corresponds to the tooth-like or undercut arrangement between the sliding carriage and the sealing element. This leads to the movements of the sliding carriage not having to be additionally synchronised in order to open the closure shutter and to expel the sealing element. When the closure shutter is in the open state, the rear region of the closure shutter is fixed by the resilient force of the spring device and/or by the aerodynamic forces which

act on the closure shutter. These forces can also fix the front region of the closure shutter in the open state. However, the front region of the closure shutter is preferably held by a fixing device which is fitted between the closure shutter and the air intake, the fixing device particularly preferably being a sliding bar which engages in a groove and 5 which is biased by a spring. This is advantageous above all when the geometry of the front region of the closure shutter is constructed in such a manner that the forces of the air flow can fall away or change direction.

The solution to the problem relating to the method of manufacture is characterized 10 according to the invention in that components which are located in the air duct are screwed to the sliding carriage by means of assembly screws, this assembly is introduced into the air duct from the front and the assembly screws are removed from outside after the components have been fixed.

15 In contrast to the individual components being assembled, this method of manufacture offers the possibility that the assembly comprising the internal components with the sliding carriage can be completely assembled outside the air duct which has a very low constructional height and the assembly is thereby considerably simplified.

20 The invention is described in greater detail with reference to one embodiment which is illustrated in the drawings and from which further details, features and preferred configurations will be appreciated: Figure 1 is a longitudinal section through an air intake according to the invention, 25 with the closure shutter in the closed position, Figure 2 is a section corresponding to Figure 1, with the closure shutter open, and Figure 3 is a cross-section through the air intake according to the invention along line 30 A-A, corresponding to Figure 1.

The air intake for an engine of a flying object is illustrated in the Figures, in which the same components are provided with the same reference numerals, which flying object serves, for example, to be carried by carrier aircraft and to be launched during flight.

The air intake is intended to be closed both during the handling thereof on the ground 5 and during flight until the launch operation in order to prevent the introduction of

foreign bodies, such as hail, stones, birds or water, and in order to strengthen the air intake, which has a rectangular cross-section in the embodiment illustrated, in such a manner that it cannot be distorted from the original shape and/or become locally dented.

At the same time, the scarfed peripheral edges of the intake contour of the air intake in to the flying direction are intended to be protected against erosion during the carrier flight in that they are not in an exposed position.

Figure 1 shows the air intake l for the air duct 20 of a ram jet engine having an air discharge duct 60 for directing away the boundary layer, in which air intake the closure 15 shutter 10, which completely closes the intake contour and which is conformed thereto and which, in the closed position thereof, covers the scarfed front edges 21, 22 with the side flanks 21a, 21b (see Figure 2), is constructed in one piece and is connected to an actuation mechanism. The actuation mechanism comprises a helical spring 30, which is articulated between the front region 11 of the closure shutter 10 and a spring 20 articulation point 25 on the air duct (in order to give an overview, the spring is not drawn continuously so that the lever mechanism 31, 32, 33 is not obscured). In the closed state, the closure shutter 10 is thereby pressed and fixed against the front intake edge 21. A rubber lip 18 seals the air intake between both components. The rear region 12 of the closure shutter 10 is connected to the air duct via a displaceable articulation 25 point 31 by means of a sliding carriage 50. A lever 33, which is rotatably articulated to the closure shutter 10, is rotatably connected to an extension arm 32 which is fitted to the articulation point 31. The sliding carriage 50 is secured against vertical displacement by means of a locking bolt 81. In the closed position of the closure shutter 10, the lever combination 31, 32, 33 presses the rear region 12 of the closure shutter 10 30 against the rear intake edge 22 and is sealed relative thereto by means of a sealing lip 19. At the same time, the rear region 12 of the closure shutter 10 is additionally guided via a control cam. To this end, a region of the closure shutter 10 which is in the form of

an extension arm 15 abuts a formed member 34 which is in the form of a control cam and which is fitted in a rigid manner to the wall of the air duct 20 and guides the rear region 12 of the closure shutter 10 from the start position (closed state) into the end position (open state) when the rear region 12 of the closure shutter 10 is moved. In the 5 closed state, the closing action of the spring 30 is mechanically supported by the projection on the formed member 34 relative to the extension arm 15. In the closed state in the present embodiment, the resilient force of the helical spring 30 and the aerodynamic forces which are applied from outside on the closure shutter 10 act thereon with a force which would support the opening operation and which would lead to the 10 opening of the closure shutter 10. Alternatively, however, it would also be possible to provide the force required to open the closure shutter 10 using other means, for example, by means of a drive.

Owing to the vertical fixing of the articulation point 31 via the sliding carriage 50 by 15 means of the locking bolt 81 and by the extension arm 15 which abuts the formed member 34, however, the closure shutter 10 undergoes no opening movement in spite of the forces being applied. Opening should be effected only when the engine is started up after the acceleration phase has ended, for example, at a speed greater than Mach 2, the closure shutter 10 then having to release the air intake within a few milliseconds. In 20 the embodiment illustrated, this occurs when the sliding carriage 50 is released towards the rear. The release of the sliding carriage 50 and consequently opening of the closure shutter 10 is controlled by the blocking device 80. To this end, a vertically moveable locking bolt 81 fixes the sliding carriage 50 in the start position thereof. The locking bolt 81 is moved by a lifting piston 82. To this end, the lifting piston 82 is located in a 25 pressure cylinder 83 which can be acted upon with gas. The lifting piston 82 is held by means of a securing bolt 84, which engages in a groove on the lifting piston 82 and which is in the form of a further lifting piston, in order to prevent the sliding carriage 50 from being inadvertently operated during flight. When pressure is applied by the pressure cylinder 83, the moveably and resiliently supported securing bolt 84 is pressed 30 out of the groove on the lifting piston 82 and the lifting piston 82 itself is then guided downwards, the locking bolt 81 then releasing the sliding carriage 50. Alternatively,

however, it would also be possible for the lifting piston 82 to eject the securing bolt 84 and cause the sliding carriage 50 to be released in this manner.

After the sliding carriage has been released, the articulation point 31 which is connected 5 to the sliding carriage guides the lever 33 to the rear and the extension arm 15 travels to the rear on the formed member 34. At the same time, the front region 11 of the closure shutter 10 is pulled inwards by the force of the helical spring 30. Furthermore, when the sliding carriage 50 moves to the rear, it also releases the sealing element 70, which protects the air discharge duct 60 against contamination in the closed state and which is 10 undercut by the sliding carriage 50 in the closed state and which, during release, is expelled by the pressure of air flowing out of the air discharge duct 60.

Figure 2 shows the air intake I in the open state with the closure shutter 10 folded inwards and the air discharge duct 60 open.

The locking bolt 81 has released the sliding carriage 50, the resilient force of the helical spring 30 and that of the aerodynamic forces has resulted in the sliding carriage 50 and the articulation point 31 being pushed towards the rear and the closure shutter 10 being folded by the extension arms 32 and levers 33 in the rear region 12. In the end position, 20 that is to say, in the open state, the rear region 12 of the closure shutter 10 abuts the spring articulation point 25 or the extension arm 15 stabilises the system by abutting the upper wall. Consequently, the rear region 12 of the closure shutter 10 has been moved in a defined manner from the closed position into the open position and is located in a stable end position. The front region 11 of the closure shutter 10 has pivoted inwards, a 25 sliding bar 41, which is biased by a spring, engaging in the groove 12 in order to secure the open position.

The cross-section A-A through the air intake 1 illustrated in Figure 3 shows that the system of the actuation mechanism is constructed in a symmetrical manner relative to 30 the centre axis B-B. For instance, the sliding carriage 50 is constructed as a plate having two articulation points 31. The extension arms 32 are located at the articulation points 31 and the levers 33 are in turn rotatably articulated to the arms 32. The levers 33

finally carry the rear region 12 of the closure shutter 10. It can also be seen that the front region 1 1 of the closure shutter 10 is secured to the air duct by two helical springs 30.

Claims

Claims

1. Air intake for an air duct of an air-breathing engine, having an intake contour, an inner closure shutter which covers the intake contour and which, when viewed in the 5 direction of flow, comprises a front region and a rear region, and having an actuation mechanism for opening the closure shutter, wherein the actuation mechanism comprises a spring device which is articulated between the front region of the closure shutter and the air duct and means articulated to the rear region of the closure shutter for pivoting and displacing the closure shutter.

2. Air intake according to claim 1, wherein the spring device and/or aerodynamic forces on the closure shutter are arranged to produce a force which serves to displace and pivot the closure shutter.

15 3. Air intake according to claim 1 or 2, wherein the pivoting and displacing means comprise levers which can be displaced in a linear manner in the direction of flow.

4. Air intake according to any one of the preceding claims, wherein the rear region of the closure shutter is guided by means of a control region which abuts a member in 20 the form of a control cam.

5. Air intake according to claim 4, wherein the control region is in the form of an extension arm on the closure shutter.

25 6. Air intake according to any one of the preceding claims, wherein a sliding carriage, which is fixed by a blocking device, allows the closure shutter to be displaced and consequently opened when the blocking device is released.

7. Air intake according to claim 6, wherein the blocking device comprises a 30 locking bolt, which fixes the sliding carriage and which can be moved by means of a lifting piston which is fitted in a pressure cylinder and which is fixed relative to the

working stroke thereof by means of a securing bolt, and the securing bolt releases the lifting piston when pressure is applied by the pressure cylinder.

8. Air intake according to claim 6 or 7, wherein the sliding carriage, when 5 displaced, releases an air discharge duct for directing away a boundary layer.

9. Air intake according to claim 8, wherein the sliding carriage, when displaced, expels a sealing element which closes the air discharge duct.

10 10. Air intake according to any one of the preceding claims, wherein a fixing device fixes the front region of the closure shutter in the open state.

1 1. Air intake according to claim 10, wherein the fixing device comprises a sliding bar which engages in a groove and which is biased by a spring.

12. Air intake according to any one of the preceding claims, suitable for use with a ram jet engine or a ram jet rocket engine of an object capable of supersonic flight.

13. Air intake for an air duct of an air-breathing engine, substantially as 20 hereinbefore described with reference to the accompanying drawings.

] 4. Method of manufacturing an air intake according to any one of claims 6 to 11, wherein components which are located in the air duct are screwed to the sliding carriage by means of assembly screws, this assembly is introduced into the air duct from the 25 front, and the assembly screws are removed from outside after the components have been fixed.

15. Method of manufacturing an air intake, substantially as hereinbefore described with reference to the accompanying drawings.