DE102021113196A1 - Reversible air intake device for engine air - Google Patents

Abstract

An air intake device (100) for an air intake of an aircraft is specified. The air intake device (100) has several air guiding arrangements (130). An air guide arrangement (130) has an inlet plate (131), an outlet plate (139) and a plurality of pivot plates (133, 135, 137) arranged therebetween. The outlet plate and pivot plates can be rotated about a central axis of the air intake device by means of adjustment rings so that the air guide assembly (130) can be moved from a straight condition to a curved condition and vice versa. The air intake device allows an engine to be selectively switched between a low radar signature condition and a high power condition.

Description

technical field

The description relates to an air intake device for use in an air intake for an engine, as can be advantageously used, for example, in jet aircraft and in particular in supersonic aircraft such as military combat aircraft.

Technical background

Engines, such as jet engines, are supplied with air and a fuel in order to generate propulsion energy for an aircraft. The air is taken from the environment of the aircraft and is supplied to the engine via an intake port.

For high performance or high drive power of the engine, it is advantageous if the inlet flow, i.e. the air taken into the inlet opening, has high energy. For this purpose, it is fundamentally advisable for the air taken into the intake opening to be guided in a straight line onto the engine. However, such an architecture can have the disadvantage that the engine itself and engine-related components are "visible" to radar systems through the engine air inlet opening, i.e. the engine has a significant radar signature and is therefore detrimental to the radar signature of the aircraft.

In order to reduce the radar signature and thus improve camouflage against radar reconnaissance, the air intake (i.e. the air duct which extends from the intake opening to the engine and leads the air from the environment to the engine) can have a curved course, so that the engine cannot be seen in a straight line through the air intake. Such a curved path of the air intake improves the radar signature of the aircraft, but can negatively affect the performance of the engine because the curved path has adverse effects on the air flow in the air intake.

Another possibility to reduce the radar signature of the engine is, for example, the use of a coating for the inner surface in the air intake, which at least absorbs electromagnetic waves in the wavelength range of a radar system. The disadvantage of such a coating is the high weight and the high maintenance costs, because the coating has to be refreshed regularly because it is gradually being removed by the high speed of the inflowing air.

Description of the invention

It can be considered a task to design an air intake for an engine in such a way that the radar signature of an aircraft is low and the performance of the engine is as high as possible.

This object is solved with the subject matter of the independent claim. Further developments result from the dependent claims and the following description.

According to one aspect, an air intake device for an air intake duct to an engine of an aircraft is specified. The air intake device includes a frame, a center tube extending along an air flow direction, and a plurality of air guide assemblies extending between the frame and the center tube. An airfoil assembly includes an inlet panel, a first pivot panel, a second pivot panel, a third pivot panel, and an outlet panel. The inlet plate and the first pivot plate are pivotally connected to each other via a first pivot axis. The first pivot plate and the second pivot plate are pivotally connected to each other via a second pivot axis. The second pivot plate and the third pivot plate are pivotally connected to each other via a third pivot axis. The third pivot plate and the outlet plate are pivotally connected to each other via a fourth pivot axis. The first pivot axis, the second pivot axis, the third pivot axis, and the fourth pivot axis run in such a way that they intersect at a common point of intersection, which lies on a central axis of the air inlet device.

The air intake device is particularly suitable for use in a jet aircraft. Such an air inlet device can be used to be arranged in an air duct or an air inlet between an inlet opening in the outer wall of the aircraft and the engine or a compression stage of the engine. The air inlet is designed to take in air from the environment and to feed it to an engine, in particular a jet engine, and to generate drive energy for the aircraft in combination with a fuel or propellant. The air is guided from the air inlet to the engine via suitable mechanisms that are known in principle.

The air intake device allows switching between two states: a state with a rectilinear course of the air guiding arrangements and a state with a curved course of the air guide arrangements. In the state where the air-guiding arrangements run in a straight line, the power of the engine is higher, but the radar signature of the aircraft is also higher because the engine, in particular its first compressor stage, has a high radar signature. In the swept path condition of the airfoils, the radar signature is significantly reduced, but engine performance may be reduced due to the turning of the air. Depending on the requirements of the aircraft's mission profile, one or the other state of the air intake arrangement can be selected. In other words, the air intake device allows the engine to be selectively switched between a low radar signature condition and a high power condition of the engine.

The pivot axes intersect in both states at said common point of intersection, ie both in the straight and in the curved state of the spoilers and in each state between these two states when the spoilers from the straight course to the curved course state rotated (or vice versa).

Preferably, the frame is cylindrical and the air guide assemblies extend in the radial direction of the frame between the frame and the center tube, with the inlet plate, the pivot plates and the outlet plate not touching the center tube and being slightly spaced therefrom, e.g. by a few tenths of a millimeter to a few millimeters.

The plates of the air guiding arrangement are arranged sequentially one behind the other in the stated order along the direction of flow. Incoming air first hits the inlet plate and then flows past the first, second, third pivot plates and finally the outlet plate.

The pivoting plates can perform a pivoting movement about the respective connected pivoting axes and thus deflect the air flow, because the angular position of the pivoting plates in relation to the air flow direction can be changed by the pivoting movement. However, the inlet plate and the outlet plate do not change their angular position to the air flow. Preferably, the inlet panel and the outlet panel extend along the air flow direction.

Preferably, all air guiding arrangements of the plurality of air guiding arrangements are structurally and functionally identical or at least similar.

Each pivot axis provides a hinge between the connected elements and allows the connected elements to be at variable angles with respect to each other. For example, the joint can be designed as a hinge and has a pin or a shaft, via which the respective connected elements are pivotally connected to one another.

The structure described here enables the outlet plate to be rotated in the circumferential direction of the frame with respect to the inlet plate to such an extent that the air guide arrangement has a double curvature. The outlet panel may be rotated circumferentially sufficiently to occlude or disrupt a straight line of sight between adjacent louver assemblies when the outlet panel is rotated past the inlet panel of the adjacent louver assembly. Thus, a direct line of sight to an engine behind the airfoil assembly is closed and the aircraft's radar signature is reduced.

The air intake device can be switched between two states. In one state, the air guide arrangements have a curved course. Also in this condition, the spaces between adjacent airfoil assemblies have a curved course, i.e. the direct view of the engine through the air intake is blocked, the aircraft has a low radar signature. However, due to the curved course of the air guide arrangements, the performance of the engine can be slightly lower. In the other state, the air guiding arrangements have a rectilinear course. The gaps between adjacent air guide arrangements also run in a straight line, i.e. there is a direct view of the engine. In this condition, air flows almost unimpeded and in a straight line onto the engine, the engine performance is higher than with the curved path of the spoilers, but the radar signature is also higher in this condition than in the curved path of the spoilers. This switching process is made possible by the construction of the air guide arrangements from the individual panels and the orientation of the pivot axes.

The air intake device described here makes it possible to switch between the states mentioned during the operating time (during flight or during the mission) of an aircraft, for example when the conditions require switching (high engine power required as opposed to low radar signature required).

An air guide assembly can also be constructed from more than three pivot panels located between the inlet panel and the outlet panel. In order to enable a longitudinally concurrent curvature on the inlet side and on the outlet side of the air intake device, an odd number of swivel plates is used, with the first and last swivel plate (numbering based on the order in the air flow direction) being mirror-symmetrical, as are the second and penultimate swivel plate are mirror-symmetrical, the third and the third to last pivoting plate are also mirror-symmetrical, etc. The use of an odd number of pivoting plates makes it possible for the air guide arrangement to be doubly curved, i.e. first execute a right-hand curve, which then turns into a left-hand curve at a turning point , or the other way around. The air flows straight into the air intake and thus passes between the inlet plates of adjacent spoilers, then the air is redirected by the pivot plates and the outlet plates of adjacent spoilers again direct the air straight out of the air intake and onto the engine.

According to one embodiment, the frame and the center tube have a circular cross-section.

This construction promotes the above-mentioned switching process between the two states of the air-guiding arrangement. In particular, the center tube has a diameter which is small in relation to the length of the center tube (for example less than a third of the length or even less than 10% of the length). With this configuration, there is a direct line-of-sight area to the engine regardless of the condition of the airfoil assemblies, but the direct line-of-sight area has a very small aperture angle and the impact on the radar signature is therefore small.

According to a further embodiment, the first pivoting plate, the second pivoting plate and the third pivoting plate have a variable extension along the air flow direction.

Preferably, the inlet panels of the airfoil assemblies remain in the same position and maintain their orientation in all conditions. The outlet plates are preferably only moved in the circumferential direction of the frame, but do not move along the air flow direction, nor do they change their orientation. In order to then achieve a curved profile of the surface of the air guiding arrangement, the pivoting plates have a variable length.

In principle, it is conceivable that the pivoting plates are constructed from an elastically deformable material, so that their length can be adapted to the position of the pivoting axes. Usually, however, the swivel plates are made of a metallic material that is hardly deformable in the elastic range.

However, in order to allow a change in length, the swivel plates can consist of two elements, for example, and can be constructed according to the telescopic principle. One element can be slid into a cavity of the other element to effect the change in length of the pivot plate. The pivot plates may be constructed such that relative displacement of the elements of the plates to each other varies depending on the distance from the center tube. In particular, the course of the curvature of the air guiding arrangement is more pronounced as the distance from the center tube increases than at a smaller distance from the center tube. The greater the distance from the central tube, the clearer the relative movement of the two elements to one another.

According to a further embodiment, the air intake device also has a plurality of adjustment rings. A first adjustment ring is connected to the first pivot plate and the second pivot plate at the second pivot axis. A second adjustment ring is connected to the second pivot plate and the third pivot plate at the third pivot axis. A third adjustment ring is connected to the third pivot plate and the outlet plate at the fourth pivot axis.

The shape of the air guiding arrangement can be varied by means of the adjusting rings by rotating the adjusting rings about the central axis of the frame and by entraining the swivel plates and the outlet plate during this movement.

No adjustment ring is arranged on the first pivot axis between the inlet plate and the first pivot axis because the first pivot axis is not moved in the circumferential direction about the central axis. The inlet plate does not change its position or its orientation. The first pivot plate changes its angular position with respect to the inlet plate when the second pivot axis is moved circumferentially.

The air intake device can have a plurality of air guiding arrangements in the form of radially extending air guiding plates. These airfoil assemblies extend from the center tube to the frame. The frame has the adjustment rings. All airfoil assemblies are attached to adjustment rings as indicated, so all pivot plates of all air guide assemblies are carried along when the adjustment rings are rotated about the central axis.

According to a further embodiment, each adjustment ring is connected to the respective associated pivot plates such that the pivot plates perform a rotational or pivotal movement relative to the adjustment ring when the adjustment ring is rotated about the central axis of the frame.

An adjustment ring forms part of the jacket of the frame and the central axis of the air intake device also forms the central axis or a center point of the adjustment ring and runs perpendicular to the plane of rotation of the adjustment ring. When the adjustment ring is rotated about the central axis, it carries the pivot plates and the outlet plate with it, with different pivot plates being carried by different adjustment rings to different extents in the circumferential direction, so that these movements of the adjustment rings cause a curved course of the louver assemblies.

According to a further embodiment, the plurality of adjustment rings forms a section of the frame and the adjustment rings are arranged one behind the other along the air flow direction.

According to another embodiment, the air intake device further includes an actuator connected to each of the plurality of adjustment rings such that movement of the actuator is transmitted to the adjustment rings to rotate the adjustment rings about the central axis.

The actuator may also function to hold the adjustment rings in an assumed condition so that air flow does not inadvertently push the louver assemblies back to the straight condition.

According to a further embodiment, the actuator is connected to each adjustment ring via a gear and the actuator is connected to each adjustment ring via a different gear ratio.

The actuator is, for example, an electric motor, an electro-hydraulic drive or another source of mechanical energy that is provided as movement. For example, a rotational movement is provided via a drive shaft. Various gears are arranged on the drive shaft, one of which is connected to an adjustment ring, so that a rotation of the gear is transmitted to the adjustment ring. For example, a rack is arranged on an outer surface of the adjustment ring. If the actuator rotates the drive shaft, and thus the gear wheel, this rotary movement is transmitted to the toothed rack and the adjusting ring rotates accordingly about the central axis, carrying the pivot plates or the outlet plate with it in order to change the air guiding arrangement from one state to another . Depending on the direction of rotation, the air guiding arrangements are moved from the state in which the air guiding arrangements run in a straight line to the state in which the air guiding arrangements run in a curved manner, or vice versa.

In principle, it is also conceivable that the air guiding arrangements are brought into an intermediate state and remain in this intermediate state for a predetermined period of time. The intermediate state is a state of the air guiding arrangements in which the air guiding arrangements are between the state with a rectilinear course and the state with a maximally curved course.

The translation between the drive shaft and the adjusting ring can be varied, for example by using a gear with a different translation. The differential translation is used because the sequentially arranged pivot plates must be rotated about the central axis by increasing deflection amounts in order for the airfoil assembly to assume a curved course.

According to a further embodiment, the inlet plate and the outlet plate are always aligned along the air flow direction, regardless of a rotational position of the adjustment rings.

The air can thus flow straight against each air-guiding arrangement and, on the outlet side, is guided in a straight line by the outlet plates onto the engine or a first compressor stage of the engine.

The inlet plate does not change position or orientation when the adjustment rings are turned. The outlet plate, on the other hand, is carried along in the circumferential direction by the adjustment ring connected to it, but retains its orientation in relation to the air flow or the air flow direction. In other words, both the inlet plate and the outlet plate run along the central axis of the frame. In contrast to the inlet panel and the outlet panel, the pivoting panels at least change their orientation with respect to the air flow direction. The first pivot plate is pivotally connected at its leading edge to the inlet plate. When the adjustment rings rotate, the first pivot plate only pivots with respect to the inlet plate. However, the trailing edge of the first pivot plate is of the first adjustment ring is carried around the central axis in the circumferential direction when the first adjustment ring is rotated. This movement results in the front edge of the second pivot plate also being carried along in the circumferential direction. In order to achieve the curved course of the air guiding arrangement, the rear edge of the second pivoting plate is guided even further in the circumferential direction by the second adjusting ring than the front edge of the second pivoting plate. The second swivel plate changes its position and its orientation during the rotary movement of the adjustment rings. The trailing edge of the second pivot plate and the leading edge of the third pivot plate are connected to each other and to the second adjustment ring at the third pivot axis. The second adjustment ring thus moves both the rear edge of the second pivot plate and the front edge of the third pivot plate. The third pivot plate and the outlet plate are connected to each other and to the third adjustment ring at the fourth pivot axis. If the third adjustment ring is moved, it moves the third swivel plate and the outlet plate with it. The third adjustment ring moves the trailing edge of the third pivot plate further circumferentially than the leading edge of the third pivot plate was moved by the second adjustment ring. The third adjustment ring thus changes both its position and its orientation. The third adjustment ring guides the outlet plate during rotation so that the outlet plate maintains its orientation. In other words, the outlet plate is non-rotatably movable with respect to the third adjustment ring and is carried along with the third adjustment ring as it rotates.

The structure of an air intake device with three swivel plates and three adjustment rings was described here as an example. Other embodiments are possible, with more than three pivot plates and a correspondingly adjusted number of adjustment rings.

According to a further embodiment, the frame has a cross-sectional widening in the air flow direction in front of the air guiding arrangements and has a cross-sectional constriction in the air flow direction behind the air guiding arrangements.

The widening of the cross section widens the cross section of the air inlet device by the amount by which the air guiding device reduces the cross section. Thus, an effective flow cross-section available for the engine air remains essentially the same along the air inlet from the inlet opening to the engine. The widening of the cross section and the constriction of the cross section can be designed, for example, as conical areas in which the diameter or the cross section changes along the air flow direction.

character list

• 1 zeigt eine schematische Darstellung eines Luftfahrzeugs.
• 2 zeigt eine schematische Darstellung einer Lufteinlassvorrichtung.
• 3 zeigt eine schematische Darstellung der Lufteinlassvorrichtung aus 2 in einer Schnittdarstellung.
• 4 zeigt eine schematische Querschnittsdarstellung einer Lufteinlassvorrichtung mit dem Aufbau einer Luftleitanordnung.
• 5 zeigt eine schematische Darstellung eines Einstellrings der Lufteinlassvorrichtung.
• 6 zeigt eine schematische Darstellung einer Luftleitanordnung mit Einlassplatte, Schwenkplatten und Auslassplatte in einem geradlinigen Zustand.
• 7 zeigt eine schematische Darstellung einer Schwenkplatte.
• 8 zeigt eine schematische Darstellung einer Luftleitanordnung mit Einlassplatte, Schwenkplatten und Auslassplatte in einem gekrümmten Zustand.
• 9 zeigt eine schematische Darstellung der Lufteinlassvorrichtung mit den Luftanordnungen in einem gekrümmten Zustand.
• 10 zeigt eine schematische Darstellung der Lufteinlassvorrichtung mit den Luftanordnungen in einem geradlinigen Zustand.

Further details are described with reference to the figures. The figures are schematic and not drawn to scale.

• 1 shows a schematic representation of an aircraft.
• 2 shows a schematic representation of an air intake device.
• 3 FIG. 12 shows a schematic representation of the air intake device from FIG 2 in a sectional view.
• 4 shows a schematic cross-sectional view of an air intake device with the structure of an air guiding arrangement.
• 5 shows a schematic representation of an adjustment ring of the air intake device.
• 6 Figure 12 shows a schematic representation of an air guide assembly with inlet panel, pivot panels and outlet panel in a straight state.
• 7 shows a schematic representation of a swivel plate.
• 8th FIG. 12 shows a schematic representation of an air guide assembly with inlet panel, pivoting panels and outlet panel in a curved state.
• 9 Figure 12 shows a schematic representation of the air intake device with the air arrangements in a curved state.
• 10 Figure 12 shows a schematic representation of the air intake device with the air arrangements in a straight state.

Detailed Description of Embodiments

1 shows an aircraft 1. The aircraft 1 has a fuselage 3 with wings 5 arranged laterally thereon. In addition, the aircraft 1 also has control surfaces (elevator, rudder, landing flaps, etc.) which are arranged on the fuselage or the wings, with the control surfaces not being separately identified by reference symbols in the present case and only being mentioned here for the sake of completeness.

Air inlet openings 7 are arranged on the fuselage, typically laterally on the fuselage and below the wings 5. However, it should be understood that the positioning of the air inlet openings is shown here purely by way of example and is not decisive for the design of the air intake device described.

The air inlet openings 7 take in air from the environment and pass it on to the engine 10 or engines 10, among other things. The air is guided from the air inlet opening 7 via a duct to the engine 10 or its first compressor stage.

Various measures are sometimes taken to keep the radar signature of an aircraft low. One is to avoid a direct line of sight from the front of the engine and its compressor first stage, because the engine or its compressor first stage is a very strong reflector of radar signals. The direct line of sight can be avoided by curving the duct between the air intake port and the engine. However, this has the disadvantage that the air has to follow the curvature and the air flow can be influenced as a result, which is disadvantageous for the engine.

An alternative to curved air inlets or air ducts is the use of an air inlet device which is arranged in the air duct between the air inlet opening and the engine. The air intake device makes it possible for the engine to have a straight flow and for the air to have little or no turbulence.

The air intake device described here combines several properties: a direct line of sight to the engine can optionally be avoided; the air continues to flow straight against the engine; the air intake device can be switched to a state in which it passes the air straight through to the engine. The air intake device thus combines properties that are advantageous for camouflage from radar reconnaissance with properties that do not restrict engine performance, so that the desired setting of the air intake device can be selected depending on a mission profile.

2 12 shows a schematic representation of an air intake device 100. The air intake device 100 has a frame 110, a central pipe 120, and a plurality of air guiding arrangements 130. FIG. The shroud assemblies 130 extend radially from the center tube to the frame 130. The shroud assemblies 130 may also be referred to as shrouds. The air guide assemblies 130 are arranged in the circumferential direction around the central tube 120 such that a gap is formed between adjacent air guide assemblies 130 through which air can flow from an inlet side to an opposite outlet side.

3 FIG. 12 shows the representation of the air intake device 100. FIG 2 with a section to show the curved course of the air guide assemblies 130 from the inlet side to the outlet side (in the illustration of FIGS 2 and 3 from left to right) to follow. The air flows in a straight line against the front edge of the air guiding arrangements 130 . The air guide assembly 130 then transitions into a right-hand curve, which transitions into a left-hand curve before the rear edge of the air guide assembly guides the air out of the air intake device 100 again along the central axis of the frame. In the curved state of the spoiler assemblies 130 shown, there is no direct line of sight from the intake side to the exhaust side because the trailing edge of the spoiler assembly is twisted in the circumferential direction relative to the leading edge of the spoiler assembly to such an extent that each gap between adjacent spoiler assemblies is curved toward a direct line of sight is blocked.

4 12 shows a cross-sectional view of the air intake device 100 with an air guide assembly on both sides of the center tube 120, each air guide assembly being divided into inlet plate 131, pivot plates 133, and outlet plate 139. FIG. In 4 the air flow direction 11 is drawn in from left to right. The air moves towards the inlet side, through the air inlet device 100, and then flows from the outlet side to the engine (not shown). The air intake device 100 has a central axis 122 which runs essentially parallel to the air flow direction 11 (apart from the air flow direction in the curved areas of the air guide arrangements).

In 4 it can be seen that the cross section of the air inlet device 100 widens in front of the air guiding arrangements (left) and reduces or narrows behind the air guiding arrangements (right). The air inlet duct 9 accordingly has a cross-sectional widening on the inlet side and a cross-sectional constriction on the outlet side, so that the frame 110 has a conical area at the corresponding points.

An air guide assembly can be seen above and below the center tube 120, respectively. The two air guiding arrangements are symmetrical to one another with respect to the central axis 122. Each air guiding arrangement has another axis of symmetry, namely a vertical axis of symmetry in FIG 4 , which runs centrally through the second pivot plate 135. However, it is pointed out that there may be embodiments that do not have this vertical axis of symmetry.

The structure of an airfoil arrangement will now be described from left to right (from the inlet side to the outlet side). The inlet plate 131 is located first in the air flow at the front. The inlet plate 131 is connected to the first pivot plate 133 along the first pivot axis 132 . The first pivot plate 133 is connected to the second pivot plate 135 along the second pivot axis 134 . The second pivot plate 135 is connected to the third pivot plate 137 along the third pivot axis 136 . The third pivot plate 137 is connected to the outlet plate 139 along the fourth pivot axis 138 . All of the pivot axes allow the respective connected elements to be pivoted about the pivot axis with respect to each other to change a relative angular position, as will be described in more detail below.

The inlet plate 131 is immovably connected to the frame 110 . A first adjustment ring is connected to the first pivot plate 133 and the second pivot plate 135 in the region of the second pivot axis 134 so that the first and second pivot plates can be rotated in the circumferential direction about the central axis 122 with the aid of the first adjustment ring. When the first adjustment ring is moved, i.e. rotated circumferentially about the central axis 122, the second pivot axis 134 follows this movement and the first pivot plate 133 pivots with respect to the inlet plate 131 and the second pivot plate 135 pivots with respect to of the third pivot plate 137. A second adjustment ring is connected to the second pivot plate 135 and the third pivot plate 137 in the region of the third pivot axis 136, the second adjustment ring moving the second and third pivot plates according to the same mechanism as the first adjustment ring the first and second pivot plates. A third adjustment ring is connected to the third pivot plate 137 and the outlet plate 139 in the area of the fourth pivot axis 138 . As the third adjustment ring is rotated about the central axis 122, the outlet plate is carried along with this movement while maintaining the orientation of the outlet plate.

The swing plates 133, 135, 137 are designed in the shape of a regular or irregular trapezium. The pivot axes 132 , 134 , 136 , 138 extend in such a way that they intersect at the common point of intersection 140 , the common point of intersection 140 lying on the central axis 122 .

5 12 shows a front view of the air intake device 100. It can be seen that the frame 110 is circular and the center tube 120 is in the center thereof. Air guide assemblies 130 extend from the center tube 120 to the frame.

It applies to all embodiments and examples that an opening angle between adjacent air guiding arrangements 130 can be the same, so that the gaps are equal and the air guiding arrangements 130 are evenly distributed around the central pipe.

6 shows in a detailed representation the connection of an air guide arrangement 130 with the three adjustment rings 143, 145, 147. From left to right, the inlet plate 131 is shown first, which is connected to a first pivot axis 132 with a front edge of the first pivot plate 133. The rear edge of the first pivot plate 133 is connected to the front edge of the second pivot plate 135 at the second pivot axis 134 . The rear edge of the second pivot plate 135 is connected to the front edge of the third pivot plate 137 at the third pivot axis 136 . The rear edge of the third pivot plate 137 is connected to the front edge of the outlet plate 139 at the fourth pivot axis 138 .

A first adjustment ring 143 is connected to the second pivot axis 134 such that the first adjustment ring 143 entrains the second pivot axis 134 when it is rotated about the central axis 122 . A second adjustment ring 145 is connected to the third pivot axis 136 and a third adjustment ring 147 is connected to the fourth pivot axis 138 .

When the adjustment rings 143, 145, 147 are turned, the pivot plates and the outlet plate are removed from the in 6 state shown in a curved state. The curved state is in 8th shown. However, before moving on to the curved state in 8th is discussed, the construction of a swivel plate is shown.

7 shows the basic structure of a swivel plate, here using the example of the first swivel plate 133. The first swivel plate consists of a first section 133A and a second section 133B. the first section 133A is connected to the first pivot axis 132 , the second section 133B is connected to the second pivot axis 134 . The first section 133A has a U-shaped profile into which the second section 133B can be inserted or withdrawn. In both the stowed and extended states, the pivot panel (and also the other pivot panels) has a continuous surface capable of directing and directing airflow to the engine. The construction of the pivot plates allows the first section 133A and the second section 133B to be used individually or simultaneously tig can be moved relative to each other, as the arrows on the pivot axes 132, 134 show.

When the airfoil assembly 130 is moved from the straight state to the curved state (or vice versa), there is a change in length of the pivot plates. the inside 7 The structure shown enables this change in length.

8th 13 shows the airfoil assembly 130 in a flexed condition. Related to 6 the first adjustment ring 143 was rotated by a first angular amount in the circumferential direction about the central axis 122. At this time, the first pivot plate 133 has increased in length, the second member 133B has been pulled out from the first member 133B. The first pivot plate 133 has pivoted relative to the inlet plate 131 about the first pivot axis 132 . The second adjustment ring 145 has been rotated about the central axis by a second angular amount, which is greater than the first angular amount, and the second element 135B of the second pivot plate 135 and the first element 137A of the third pivot plate 137, which are connected to one another at the third pivot axis 136 , carried. The third adjustment ring 147 has been rotated about the central axis by a third angular amount, which is greater than the second angular amount, and the second element 137B of the third pivot plate 137 and the outlet plate 139, which are connected to one another at the third pivot axis 138, are carried along.

In order to achieve a uniform, doubly curved course of the air guiding arrangement, the first angular amount can correspond to the difference between the second angular amount and the third angular amount.

9 and 10 show an air intake device 100 with the air guide assemblies 130 in the curved state ( 9 ) and in the even state ( 10 ). In these illustrations, an actuator 150 in the form of an electric motor is shown, which is coupled to the adjustment rings 143, 145, 47 with a gearbox 152 and gear wheels. The actuator drive shaft is coupled to the adjustment rings at different gear ratios such that the same input movement of the actuator 152 causes rotations of the adjustment rings about the central axis of different angular amounts. That is, the same movement of the drive shaft causes the third adjustment ring 147 to rotate further than the second adjustment ring 145, and the second adjustment ring 145 to rotate further than the first adjustment ring 143, so that the in 8th shown state of the air guiding arrangements 130 is reached.

10 shows that an air stream flows in a straight line along the air flow direction 11 between the air guiding arrangements 130 . In contrast, shows 9 the curved course of the air flow 11 when the air guide assemblies 130 are in the curved state.

The adjustment rings can be constructed like a wheel with a hub and spokes. The outer ring of the adjustment ring forms the surface of the frame, as in 9 and 10 you can see. A plurality of spokes extend from the outer ring to an inner ring. The inner ring can be designed as a sliding bushing that is supported on the center tube and can rotate on the center tube. The spokes of the adjusting rings are used to adjust the swivel plates and the outlet plate as in 6 and 8th shown to attach. When an adjustment ring is rotated about the central axis, attachment of the pivot plates and outlet plate, respectively, to the spokes of the adjustment ring allows the pivot plates to perform the pivotal movement about the pivot axes necessary to convert the airfoil assembly 130 from the straight state to the curved state (or vice versa).

It is pointed out that "comprising" or "comprising" does not exclude any other elements or steps, nor a higher number of elements and steps than explicitly stated, than stated in the claims and/or the description. "A" or "an" does not exclude a plurality. Features or steps that have been described with reference to one of the above exemplary embodiments can also be used in combination with other features or steps of other exemplary embodiments described above. Any reference signs in the claims should not be construed as limiting.

Reference List

1

aircraft

3

hull

5

wings, control surfaces

7

air intake opening

9

air intake duct

10

engine

11

air flow direction

100

air intake device

110

framework

120

center pipe

122

central axis

130

air guide arrangement

131

inlet plate

132

first pivot axis

133

first swivel plate

133A

first section

133B

second part

134

second pivot axis

135

second swivel plate

136

third pivot axis

137

third swivel plate

138

fourth pivot axis

139

outlet plate

140

intersection

141

space

143

first adjustment ring

145

second adjustment ring

147

third adjustment ring

150

actuator

152

drive, gearbox

Claims (10)

Air inlet device (100) for an air inlet duct (9) to an engine (10) of an aircraft, the air inlet device (100) having: a frame (110); a center tube (120) extending along an air flow direction (11); a plurality of airfoil assemblies (130) extending between the frame (110) and the center tube (120); an air guide assembly (130) having an inlet panel (131), a first pivot panel (133), a second pivot panel (135), a third pivot panel (137) and an outlet panel (139); the inlet panel (131) and the first pivot panel (133) being pivotally connected to each other via a first pivot axis (132); the first pivot plate (133) and the second pivot plate (135) being pivotally connected to each other via a second pivot axis (134); the second pivot plate (135) and the third pivot plate (137) being pivotally connected to each other via a third pivot axis (136); the third pivot plate (137) and the outlet plate (139) being pivotally connected to each other via a fourth pivot axis (138); wherein the first pivot axis (132), the second pivot axis (134), the third pivot axis (136) and the fourth pivot axis (138) extend in such a way that they meet at a common point of intersection (140) which is on a central axis (122) of the Cut the air inlet device (100). Air inlet device (100) after claim 1 wherein the frame (110) and the center tube (120) have a circular cross-section. Air inlet device (100) after claim 1 or 2 , wherein the first pivoting plate (133), the second pivoting plate (135) and the third pivoting plate (137) have a variable extension along the air flow direction (11). Air intake device (100) according to any one of the preceding claims, further comprising a plurality of adjustment rings (143, 145, 147); a first adjustment ring (143) at the second pivot axis (134) connected to the first pivot plate (133) and the second pivot plate (135); a second adjustment ring (145) connected to the second pivot plate (135) and the third pivot plate (137) at the third pivot axis (136); a third adjustment ring (147) being connected to the third pivot plate (137) and the outlet plate (139) at the fourth pivot axis (138). Air inlet device (100) after claim 4 wherein each adjustment ring is connected to the respective associated pivot plates such that the pivot plates perform rotational or pivotal movement relative to the adjustment ring when the adjustment ring is rotated about the central axis of the frame. Air inlet device (100) after claim 4 or 5 wherein the plurality of adjustment rings (143, 145, 147) forms a portion of the frame and the adjustment rings are arranged one behind the other along the air flow direction (11). Air inlet device (100) according to any one of Claims 4 until 6 , further comprising an actuator (150) connected to each of the plurality of adjustment rings (143, 145, 147) such that movement of the actuator is transmitted to the adjustment rings to rotate the adjustment rings about the central axis. Air inlet device (100) after claim 7 wherein the actuator (150) is connected to each adjustment ring via a gear (152); the actuator (150) being connected to each adjustment ring via a different ratio. Air inlet device (100) according to any one of Claims 4 until 8th , wherein the inlet plate (131) and the outlet plate (139) independently of a rotational position of the one collars are always aligned along the direction of air flow. Air intake device (100) according to any one of the preceding claims, wherein the frame (110) has a cross-sectional widening in front of the air guiding arrangements (130) in the air flow direction; wherein the frame (110) has a cross-sectional constriction behind the air guiding arrangements (130) in the air flow direction.

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