CA2522553C - Aircraft wing, method for operating an aircraft wing, and use of a pivotable trailing edge on a main wing of an aircraft, for adjusting the shape and the width of an air gap - Google Patents
Aircraft wing, method for operating an aircraft wing, and use of a pivotable trailing edge on a main wing of an aircraft, for adjusting the shape and the width of an air gap Download PDFInfo
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- CA2522553C CA2522553C CA2522553A CA2522553A CA2522553C CA 2522553 C CA2522553 C CA 2522553C CA 2522553 A CA2522553 A CA 2522553A CA 2522553 A CA2522553 A CA 2522553A CA 2522553 C CA2522553 C CA 2522553C
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B64—AIRCRAFT; AVIATION; COSMONAUTICS
- B64C—AEROPLANES; HELICOPTERS
- B64C9/00—Adjustable control surfaces or members, e.g. rudders
- B64C9/14—Adjustable control surfaces or members, e.g. rudders forming slots
- B64C9/16—Adjustable control surfaces or members, e.g. rudders forming slots at the rear of the wing
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
- Y02T50/00—Aeronautics or air transport
- Y02T50/40—Weight reduction
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Abstract
An aircraft wing comprises a main wing (301) with a pivotable trailing edge (304) and a lift-assisting flap (302) on the rear of the wing, wherein the lift-assisting flap (302) is coupled to the main wing (301) and is designed in such a way that in its retracted state (300) it rests against the main wing (301) and in an extended state (310) it forms an air gap (311) with the main wing (301). The pivotable trailing edge (304) is pivotable in such a way that by using pivoting the pivotable trailing edge (304) the shape and the width of the air gap (311) are adjustable.
Description
Aircraft Wing, Method for Operating_an Aircraft Wind, and Use of a Pivotable Trailing Edge on a Main Wing of an Aircraft, for Adiustingthe Shape and the Width of an Air Gan Field of the invention The invention relates to an aircraft wing, a method for operating an aircraft wing, and the use of a pivotable trailing edge on a main wing of an aircraft, for adjusting the shape and the width of an air gap.
Technological Background An aircraft is kept airborne by the aerodynamic lift of its wings.
An aircraft wing comprises a main wing, and in many cases also lift-assisting devices fixed to said wing. A lift-assisting device is a device on a wing of an aircraft, which device positively changes the lift coefficient at least in a range of the flight spectrum.
Lift assisting devices are in particular used during landing and during takeoff of an aircraft.
The aim is, as a result of the increased lift, to reduce the take-off speed or landing speed and thus reduce the distance required for take-off or landing.
Lift-assisting devices can be affixed to the leading edge or the trailing edge of an aircraft wing. The so-called Fowler flap is an important example of a lift-assisting device affixed to the trailing edge of a wing. A Fowler flap is a control surface which is moved to the rear below the trailing edge of the wing and is set at an angle. In this way an air gap can be formed between the top and the bottom of the wing, as a result of which the airfoil curvature is increased. At the same time the wing surface is also increased.
Technological Background An aircraft is kept airborne by the aerodynamic lift of its wings.
An aircraft wing comprises a main wing, and in many cases also lift-assisting devices fixed to said wing. A lift-assisting device is a device on a wing of an aircraft, which device positively changes the lift coefficient at least in a range of the flight spectrum.
Lift assisting devices are in particular used during landing and during takeoff of an aircraft.
The aim is, as a result of the increased lift, to reduce the take-off speed or landing speed and thus reduce the distance required for take-off or landing.
Lift-assisting devices can be affixed to the leading edge or the trailing edge of an aircraft wing. The so-called Fowler flap is an important example of a lift-assisting device affixed to the trailing edge of a wing. A Fowler flap is a control surface which is moved to the rear below the trailing edge of the wing and is set at an angle. In this way an air gap can be formed between the top and the bottom of the wing, as a result of which the airfoil curvature is increased. At the same time the wing surface is also increased.
Fig. 1 shows a retracted state 100 and an extended state 110 of a Fowler flap 102 affixed to the trailing edge of a main wing 101. In the retracted state 100 the Fowler flzp 102 rests against the main wing 101. In order to move the Fowler flap 102 from the retracted state 100 to an extended state 110, the Fowler flap 102 is first moved to the rear and then folded downward. In this way an air gap 111 is created between the main wing 101 and the extended Fowler flap 102. As shown in Fig. 1, the Fowler flap 102 is attached to the trailing edge 103 of the main wing 101.
A Fowler flap which can be extended to form an air gap jointly with a main wing is known from the state of the art, see Rudolph, P "High-Lift Systems on Commercial Subsonic Airliners", NASA Contractor Report 4746, section 1.1.2. To achieve good flow characteristics with a Fowler flap it is important that the size of the air gap created when the flap is extended be well defined, and that a divergent air gap over the entire region of the Fowler flap be prevented.
This requirement can be met by various kinematic solutions, wherein according to the state of the art the so-called track and rear-link solution (for example implemented in the Airbus A340) or the 4-bar linkage solution (for example implemented in the Boeing 777) is used, see Rudolph, P "High-Lift Systems on Commercial Subsonic Airliners", NASA
Contractor Report 4746, section I .2.2.
Pivot point kinematics (pivot point or dropped hinge), according to which the flap is extended along a circular path, are also used according to the state of the art, for example in the Boeing C 17. Such a Fowler flap 200 according to the state of the art is shown in Fig. 2. The Fowler flap 200 is brought along a circular direction of extension 201, starting from a retracted state 100 to an extended state 110.
Track and rear link kinematics shows good performance in relation to aerodynamic characteristics. Pivot point kinematics provide advantages in relation to the complexity of the system, which also results in reduced weight.
However, both the track and linkage technology and the pivot point technology are associated with disadvantages.
Due to its limitation to a circular extension path, pivot kinematics only allow the setting of a desired target state when the flap is in position. The width and the form of the gap for the intermediate states during extension result automatically and cannot themselves be set. As a rule, the settable target setting is set such that in the fully extended state 110 it produces a predefinable result. In relation to intermediary extension states the width of the air gap often takes on a value that is below the optimum value, as a result of which the quality of the functionality of the flap can be reduced, and in particular the flow characteristics of the flap can be impeded (risk of confluent boundary layer flow). Due to the circular movement the shape of the gap in an intermediate state is partly divergent. Due to local deceleration of the flow speed this leads to separation of the boundary layer flow at the flap, with subsequent deterioration of lift performance, which in addition can also lead to the occurrence of vibration and noise. In a worst-case scenario this effect can lead to a range of intermediary flap positions not being useable at all.
Furthermore, in an advanced (high) degree of extension of the flap, irrespective of the kinematics used, boundary layer separation at the flap element can occur. This effect limits the efficiency of the flap, defines the maximum usable flap angle and causes vibration of the flap elements at high angles of extension.
Summary of the Invention Thus, there may be a need to provide an aircraft wing in which the lift performance of the wing is improved, and undesirable vibration and noise are prevented.
This need may be met by an aircraft wing, by a method for operating an aircraft wing, and by the use of a pivotable trailing edge on a main wing of an aircraft, for adjusting the shape and the width of an air gap, with the characteristics according to the independent claims.
The aircraft wing according to the invention comprises a main wing with a, pivotable trailing edge and a lift-assisting flap on the rear of the wing, wherein the lift-assisting flap is coupled to the main wing and is designed in such a way that in its retracted state it rests against the main wing and in an extended state it forms an air gap with the main wing. The pivotable trailing edge is pivotable in such a way that by pivoting the pivotable trailing edge the shape and the width of the air gap are adjustable.
Furthermore, according to the invention a method for operating an aircraft wing is created in which method a lift-assisting flap that is arranged on the rear of the wing and that is coupled to the main wing is moved from a retracted state, in which the lift-assisting flap rests against the main wing, to an extended state, in which the lift-assisting flap forms an air gap to the main wing. Furthermore, a pivotable trailing edge of the main wing is hinged in such a way that by pivoting the pivotable trailing edge the shape and width of the air gap is adjusted.
Moreover, the invention provides for the use of a pivotable trailing edge on the main wing of an aircraft, for adjusting the shape and the width of an air gap between the main wing and an extended lift-assisting flap on the rear of the wing by pivoting the pivotable trailing edge.
A fundamental idea of the invention may be found in providing a pivotable trailing edge of the main wing, i.e. a pivotable element, may be provided on the rear end section of a main wing (i.e. of a wing carrier body affixed to a fuselage), and that the width and shape of an air gap between a lift-assisting flap (for example a Fowler flap) on the rear of the wing and the main wing is set to a desired value by means of rotating the pivotable trailing edge. If the width of the air gap is set so as to be constant and free of any divergence, separation of the boundary layer flow at the flap may be suppressed, and any resulting undesirable vibration and undesirable noise may be considerably reduced or entirely avoided. The high sensitivity of the air gap adjustment according to the invention may be due to the fact that only an end tip, in other words a small end region, of the main wing, namely the pivotable trailing edge of said main wing, may be set in relation to its positioning or angular position.
In this way the width of the air gap may be controlled very sensitively. Thus according to the invention only a finely adjustable end tip is swivelled.
Controlled pivoting of the end tip may make it possible to set the air gap width by means of targeted pivoting to and fro of the pivotable trailing edge throughout, in particular during the entire process of extending the lift-assisting flap (in particular a Fowler flap) on the rear of the wing, from the retracted state to the extended state.
Thus according to the invention the aerodynamics of an aircraft are improved by moving a fine end tip on a trailing edge of a wing; in the example shown a movable shroud trailing edge. This makes it possible to optimise the aerodynamic design of high-lift systems, in particular also for optimising flaps with (circular arc) pivot-kinematics.
Numeric calculations and wind channel experiments have shown that the aerodynamics of a wing comprising the pivotable trailing edge according to the invention are significantly improved compared to conventional methods.
The movable trailing edge of the wing according to the invention can extend across the entire span of the lift-assisting flap and/or of the aircraft wing, or only across part of the width. The pivotable trailing edge can be provided on an upper housing surface of the aircraft wing or can be attached to another movable component on the aircraft wing. For example a spoiler can comprise a movable trailing edge.
The trailing edge part of the wing according to the invention can be a flexible part that can be swivelled with the use of spring tension or can be operated with the use of an actuator.
When spring tension is used, for example the extendable device pushes against the movable trailing edge part of the wing, subsequently extends it from a retracted state to an extended state and leaves it in the extended state in a predefined position. A sprung plate or memory material could be an example of such a device.
'The active movement of a movable trailing edge part of the wing according to the invention can be brought about in various ways, for example by using of mechanical or hydraulic actuation or by other means, for example the use of a bimetal strip that can be electrically activated.
When the flap on the kinematic extension path moves towards the rear, starting from the retracted position, and the air gap between the shroud and the upper surface of the flap opens, the movable trailing edge part of the wing can be extended downward thus changing the shape of the air gap in a predefmable way.
The invention can be used either in the design of a new aircraft or it can be retrofitted to an already existing aircraft or aircraft model.
According to the invention the angular position of an end tip of the main wing, i.e. of a pivotable trailing edge, is set for controlling the gap width or the gap shape. It is important that the pivotable trailing edge is provided as a relatively small part of a larger component because only in that way will it be possible to achieve particularly fine control of the gap geometry, in particular in a simple extension mechanism. Preferably the length of the movable trailing edge is at most 10% of the depth of the wing element to which said trailing edge is attached.
The position of the downward pivotable trailing edge sensitively affects fine adjustment of the gap width between the flap and the main wing, and thus has an advantageous influence on the quality of the flow characteristics at the flap in an intermediate position between a retracted state and a fully extended state. According to the invention, the divergence in the gap is reduced or even completely compensated for even in a circular extension path, due to the spatially adjustable movable trailing edge. Deceleration of the airflow in the surroundings of the flap is prevented so that undesirable boundary layer separation is suppressed and vibrations and reductions in performance are prevented.
Furthermore, commencement of boundary layer separation at the flap, which separation is an issue in particular in large extension angles of a flap, can be delayed. The useful extension range of the flap can be expanded towards larger angles, and the flap performance is improved. The risk of vibration occurring at a high angle is reduced.
Preferred embodiments of the invention result from the dependent claims.
Below, preferred embodiments of the aircraft wing according to the invention are described.
They also apply to the method for operating an aircraft wing and to the use of the invention.
In the case of aircraft wing the pivotable trailing edge can be designed in such a way that by pivoting the pivotable trailing edge the width of the air gap is kept constant or convergent.
With constant width of the air gap, boundary layer separation and other causes of undesirable vibration or noise may be prevented.
The pivotable trailing edge can be designed in such a way that by means of pivoting the pivotable trailing edge the width of the air gap during extension of the lift-assisting flap from the retracted state to the extended state is at least at times kept constant or convergent. For example a control unit can be provided which during extension of the Fowler flap measures the corresponding gap and/or the width of the air gap and readjusts a drive for the pivotable trailing edge in such a way that the width of the air gap is kept constant or convergent.
The pivotable trailing edge can extend along the entire span width of the Fowler flap. As an alterative, the pivotable trailing edge can extend along only part of the span width of the Fowler flap.
The pivotable trailing edge can be attached to a housing of the main wing. In particular, the pivotable trailing edge can be attached to an upper section of the housing of the main wing.
The pivotable trailing edge can be attached to a moveable element which is attached to a housing of the main wing. In particular, the pivotable trailing edge can be attached to a spoiler which itself is attached to a housing of the main wing. Apart from the normal spoiler function, for which the spoiler is extended and thus moved, the spoiler can be operated in the retracted state in such a way that at an end section of the spoiler, which end section is on the rear of the wing, the pivotable trailing edge is formed which can be hinged across a predefinable angular range, so that a predefinable air gap width can be set precisely.
The pivotable trailing edge can be hinged by using a spring element.
As an alternative, the pivotable trailing edge can be swivelled by using a drive device which can, for example, be an electrical drive device or a hydraulic drive device.
Moreover, a vane (slat) can be provided on the aircraft wing, wherein in the extended state of the lift-assisting flap said vane is arranged between the main wing and the lift-assisting flap.
By using such a vane, an aircraft wing with a plurality of air gaps, in particular with two or three air gaps, can be formed.
In the extended state of the lift-assisting flap, several air gaps can be formed between the main wing and the lift-assisting flap.
The pivotable trailing edge is preferably designed in such a way that it is attached to the main wmg.
In the case of the aircraft wing the lift-assisting flap on the rear of the wing is preferably a Fowler flap. A Fowler flap is an element which can be moved to the rear below the trailing edge and which can be set at an angle. In this way an air gap (or several air gaps) can be formed between the topside and the buttomside of the wing, as a result of which the airfoil curvature is increased. At the same time the effective wing surface can also be increased.
According to the invention the width of the air gap is adjusted in that the pivotable trailing edge is hinged accordingly.
As an alternative, in the aircraft wing according to the invention the lift-assisting flap on the rear of the wing can be a slotted flap. In a slotted flap a control surface is tilted downward for extension. This movement simultaneously provides an air gap (or several air gaps), which admits (admit) air to the topside of the flap, thus preventing stalling. In a slotted flap the airfoil curvature is changed. According to the invention the width of the air gap is adjusted in that the pivotable trailing edge is swivelled accordingly.
l~
The invention can be applied not only to a Fowler flap or a slotted flap but to any lift-assisting flap in which in the extended state an air gap is created whose dimensions are to be controlled.
Embodiments of the invention are shown in the figures and are described in more detail below.
The following are shown:
Fig. 1 a main wing with a Fowler flap according to the state of the art;
Fig. 2 another Fowler flap on a main wing according to the state of the art;
Fig. 3 an aircraft wing according to a first embodiment of the invention;
Fig. 4 an aircraft wing according to a second embodiment of the invention;
Fig. S an aircraft wing according to a third embodiment of the invention;
Fig. 6 an aircraft wing according to a fourth embodiment of the invention; and Fig. 7A to Fig. 8B numeric flow simulations which show improved flow characteristics of the aircraft wing according to the invention.
Detailed Description of Exemplary Embodiments The drawings in the figures are diagrammatic and not to scale.
Identical or similar components in different figures have the same reference characters.
Below, with reference to Fig. 3, an aircraft wing according to a first embodiment of the invention is described.
Fig. 3 shows the aircraft wing according to the first embodiment of the invention in a retracted state 300 in which a Fowler flap 302 rests against the main wing 301, and in an extended state 310 in which the Fowler flap 302 forms an air gap 311 with the main wing 301.
Fig. 3 shows an aircraft wing with the main wing 301, the Fowler flap 302 and a pivotable trailing edge 304 of the main wing 301. The Fowler flap 302 is extendably attached to the main wing 301 (the corresponding coupling element is not shown in Fig. 3) and is equipped in such a way that in a retracted state 300 it rests against the main wing 301, and in an extended state 310 it forms an air gap 311 with the main wing 301. The pivotable trailing edge 304 is attached to an end section, more precisely to an end section on the rear of the main wing 301, and is pivotable in such a way that by pivoting the pivotable trailing edge 304 the width of the air gap 311 is adjustable.
Fig. 3 shows the pivotable trailing edge 304 in a first pivoted state 304a, in a second pivoted state 304b and in a third pivoted state 304c. The second hinged state 304b shows the end tip in its rest position. The first hinged state 304a shows an excursion of the end tip towards the top when compared to the rest position of the end tip. The third pivoted state 304c shows an excursion of the end tip towards the bottom compared to the rest position of the end tip.
Depending on the set pivoted state 304a to 304c, the width of the air gap 311 can be fine-adjusted, as a result of which undesirable airflow separations, vibration and noise in the aircraft interior are prevented. Furthermore, during the entire process of extension, i.e. during the transition from the state 300 to the state 310, the width of the air gap 311 can be directed or controlled.
The pivotable trailing edge 304 is pivotable in such a way that by pivoting the pivotable trailing edge 304 the width of the air gap 311 is held constant, namely during the transition of the Fowler flap 302 from the retracted state 300 to the extended state 310.
The pivotable trailing edge 304 extends in a direction perpendicular to the drawing plane in Fig. 3 along the entire span width of the Fowler flap 302. The pivotable trailing edge 304 is attached to an upper housing end section of the main wing 301 and is pivotable by a hydraulic drive unit (not shown).
Below, with reference to Fig. 4, an aircraft wing 400 according to a second embodiment of the invention is described.
The aircraft wing 400 shows a so-called "slotted flap", in other words a Fowler flap 302, which at a transition from the retracted state 300 to the extended state 310 only generates a single air gap. By using of a pivotable arm 401 the Fowler flap 302, by retraction and subsequent pivoting, is brought from state 300 to state 310. In order to make possible a constant width or convergence of the air gap between the Fowler flap 302 and the main wing 301 during this transition, a pivotable trailing edge 304 of the main wing 301 according to Fig. 4 is slightly moved from the top towards the bottom, e.g. using an electronic motor control system.
Below, with reference to Fig. 5, an aircraft wing 500 according to a third embodiment of the invention is described.
In the case of the aircraft wing S00 a spoiler 501 is provided on the topside of an end section on the rear of the main wing 301. If required, the spoiler 501 can be extended to influence the aerodynamic properties of the aircraft wing 500. Attached to an end section of the spoiler 501 is a pivotable trailing edge 304, which in Fig. 5 is shown in two different operating positions.
Fig. 5 shows a configuration with a "double slotted flap" so that two air gaps can be created.
To this effect a vane 502 is formed between the Fowler flap 302 and the main wing 301.
Below, with reference to Fig. 6, an aircraft wing 600 according to a fourth embodiment of the invention is described.
In a way similar to that of the aircraft wing 500, the aircraft wing 600 comprises a "double slotted flap" and has a configuration in which a main wing 301, a vane 302 and a Fowler flap 302 form a first air gap 601 and a second air gap 602, respectively. An end section of the main wing 301 again comprises a pivotable trailing edge 304, which when the Fowler flap 302 makes the transition from the retracted state to an extended state is moved from state 300 to state 310. In other words, state 300 depicts a baseline state of the pivotable trailing edge 304, while state 310 shows an end state of the pivotable trailing edge 304 in a position of maximum excursion.
Below, with reference to Figs 7A to 8B it is illustrated that with the use of the aircraft wing 600 the aerodynamic characteristics are significantly improved. Figs 7A to 8B
show computational fluid dynamics (CFD) simulations, i.e. numeric flow simulations, in which the eddy viscosity in a region surrounding an aircraft wing is graphically shown.
The CFD
simulations of Figs 7A to 8B have been calculated with an (unstructured) process using Navier-Stokes equations.
Figs 7A and 8A show the flow characteristics of an aircraft wing without the pivotable trailing edge according to the invention. Figs 7B and 8B show the improved flow characteristics when providing a pivotable trailing edge 304.
Figs 7A, 7B show that according to the invention, flow separation at medium angles of extension of the Fowler flap 302 (for example 35°) is strongly suppressed. Furthermore, Figs 8A and 8B show the improvement according to the invention of the flow characteristics in a region surrounding the flap 302 at a large angle of extension (for example 50°).
It should be noted that the term "comprising" does not exclude other elements or steps and the "a" or "an" does not exclude a plurality. Also elements described in association with different embodiments may be combined. It should also be noted that reference signs in the claims shall not be construed as limiting the scope of the claims.
A Fowler flap which can be extended to form an air gap jointly with a main wing is known from the state of the art, see Rudolph, P "High-Lift Systems on Commercial Subsonic Airliners", NASA Contractor Report 4746, section 1.1.2. To achieve good flow characteristics with a Fowler flap it is important that the size of the air gap created when the flap is extended be well defined, and that a divergent air gap over the entire region of the Fowler flap be prevented.
This requirement can be met by various kinematic solutions, wherein according to the state of the art the so-called track and rear-link solution (for example implemented in the Airbus A340) or the 4-bar linkage solution (for example implemented in the Boeing 777) is used, see Rudolph, P "High-Lift Systems on Commercial Subsonic Airliners", NASA
Contractor Report 4746, section I .2.2.
Pivot point kinematics (pivot point or dropped hinge), according to which the flap is extended along a circular path, are also used according to the state of the art, for example in the Boeing C 17. Such a Fowler flap 200 according to the state of the art is shown in Fig. 2. The Fowler flap 200 is brought along a circular direction of extension 201, starting from a retracted state 100 to an extended state 110.
Track and rear link kinematics shows good performance in relation to aerodynamic characteristics. Pivot point kinematics provide advantages in relation to the complexity of the system, which also results in reduced weight.
However, both the track and linkage technology and the pivot point technology are associated with disadvantages.
Due to its limitation to a circular extension path, pivot kinematics only allow the setting of a desired target state when the flap is in position. The width and the form of the gap for the intermediate states during extension result automatically and cannot themselves be set. As a rule, the settable target setting is set such that in the fully extended state 110 it produces a predefinable result. In relation to intermediary extension states the width of the air gap often takes on a value that is below the optimum value, as a result of which the quality of the functionality of the flap can be reduced, and in particular the flow characteristics of the flap can be impeded (risk of confluent boundary layer flow). Due to the circular movement the shape of the gap in an intermediate state is partly divergent. Due to local deceleration of the flow speed this leads to separation of the boundary layer flow at the flap, with subsequent deterioration of lift performance, which in addition can also lead to the occurrence of vibration and noise. In a worst-case scenario this effect can lead to a range of intermediary flap positions not being useable at all.
Furthermore, in an advanced (high) degree of extension of the flap, irrespective of the kinematics used, boundary layer separation at the flap element can occur. This effect limits the efficiency of the flap, defines the maximum usable flap angle and causes vibration of the flap elements at high angles of extension.
Summary of the Invention Thus, there may be a need to provide an aircraft wing in which the lift performance of the wing is improved, and undesirable vibration and noise are prevented.
This need may be met by an aircraft wing, by a method for operating an aircraft wing, and by the use of a pivotable trailing edge on a main wing of an aircraft, for adjusting the shape and the width of an air gap, with the characteristics according to the independent claims.
The aircraft wing according to the invention comprises a main wing with a, pivotable trailing edge and a lift-assisting flap on the rear of the wing, wherein the lift-assisting flap is coupled to the main wing and is designed in such a way that in its retracted state it rests against the main wing and in an extended state it forms an air gap with the main wing. The pivotable trailing edge is pivotable in such a way that by pivoting the pivotable trailing edge the shape and the width of the air gap are adjustable.
Furthermore, according to the invention a method for operating an aircraft wing is created in which method a lift-assisting flap that is arranged on the rear of the wing and that is coupled to the main wing is moved from a retracted state, in which the lift-assisting flap rests against the main wing, to an extended state, in which the lift-assisting flap forms an air gap to the main wing. Furthermore, a pivotable trailing edge of the main wing is hinged in such a way that by pivoting the pivotable trailing edge the shape and width of the air gap is adjusted.
Moreover, the invention provides for the use of a pivotable trailing edge on the main wing of an aircraft, for adjusting the shape and the width of an air gap between the main wing and an extended lift-assisting flap on the rear of the wing by pivoting the pivotable trailing edge.
A fundamental idea of the invention may be found in providing a pivotable trailing edge of the main wing, i.e. a pivotable element, may be provided on the rear end section of a main wing (i.e. of a wing carrier body affixed to a fuselage), and that the width and shape of an air gap between a lift-assisting flap (for example a Fowler flap) on the rear of the wing and the main wing is set to a desired value by means of rotating the pivotable trailing edge. If the width of the air gap is set so as to be constant and free of any divergence, separation of the boundary layer flow at the flap may be suppressed, and any resulting undesirable vibration and undesirable noise may be considerably reduced or entirely avoided. The high sensitivity of the air gap adjustment according to the invention may be due to the fact that only an end tip, in other words a small end region, of the main wing, namely the pivotable trailing edge of said main wing, may be set in relation to its positioning or angular position.
In this way the width of the air gap may be controlled very sensitively. Thus according to the invention only a finely adjustable end tip is swivelled.
Controlled pivoting of the end tip may make it possible to set the air gap width by means of targeted pivoting to and fro of the pivotable trailing edge throughout, in particular during the entire process of extending the lift-assisting flap (in particular a Fowler flap) on the rear of the wing, from the retracted state to the extended state.
Thus according to the invention the aerodynamics of an aircraft are improved by moving a fine end tip on a trailing edge of a wing; in the example shown a movable shroud trailing edge. This makes it possible to optimise the aerodynamic design of high-lift systems, in particular also for optimising flaps with (circular arc) pivot-kinematics.
Numeric calculations and wind channel experiments have shown that the aerodynamics of a wing comprising the pivotable trailing edge according to the invention are significantly improved compared to conventional methods.
The movable trailing edge of the wing according to the invention can extend across the entire span of the lift-assisting flap and/or of the aircraft wing, or only across part of the width. The pivotable trailing edge can be provided on an upper housing surface of the aircraft wing or can be attached to another movable component on the aircraft wing. For example a spoiler can comprise a movable trailing edge.
The trailing edge part of the wing according to the invention can be a flexible part that can be swivelled with the use of spring tension or can be operated with the use of an actuator.
When spring tension is used, for example the extendable device pushes against the movable trailing edge part of the wing, subsequently extends it from a retracted state to an extended state and leaves it in the extended state in a predefined position. A sprung plate or memory material could be an example of such a device.
'The active movement of a movable trailing edge part of the wing according to the invention can be brought about in various ways, for example by using of mechanical or hydraulic actuation or by other means, for example the use of a bimetal strip that can be electrically activated.
When the flap on the kinematic extension path moves towards the rear, starting from the retracted position, and the air gap between the shroud and the upper surface of the flap opens, the movable trailing edge part of the wing can be extended downward thus changing the shape of the air gap in a predefmable way.
The invention can be used either in the design of a new aircraft or it can be retrofitted to an already existing aircraft or aircraft model.
According to the invention the angular position of an end tip of the main wing, i.e. of a pivotable trailing edge, is set for controlling the gap width or the gap shape. It is important that the pivotable trailing edge is provided as a relatively small part of a larger component because only in that way will it be possible to achieve particularly fine control of the gap geometry, in particular in a simple extension mechanism. Preferably the length of the movable trailing edge is at most 10% of the depth of the wing element to which said trailing edge is attached.
The position of the downward pivotable trailing edge sensitively affects fine adjustment of the gap width between the flap and the main wing, and thus has an advantageous influence on the quality of the flow characteristics at the flap in an intermediate position between a retracted state and a fully extended state. According to the invention, the divergence in the gap is reduced or even completely compensated for even in a circular extension path, due to the spatially adjustable movable trailing edge. Deceleration of the airflow in the surroundings of the flap is prevented so that undesirable boundary layer separation is suppressed and vibrations and reductions in performance are prevented.
Furthermore, commencement of boundary layer separation at the flap, which separation is an issue in particular in large extension angles of a flap, can be delayed. The useful extension range of the flap can be expanded towards larger angles, and the flap performance is improved. The risk of vibration occurring at a high angle is reduced.
Preferred embodiments of the invention result from the dependent claims.
Below, preferred embodiments of the aircraft wing according to the invention are described.
They also apply to the method for operating an aircraft wing and to the use of the invention.
In the case of aircraft wing the pivotable trailing edge can be designed in such a way that by pivoting the pivotable trailing edge the width of the air gap is kept constant or convergent.
With constant width of the air gap, boundary layer separation and other causes of undesirable vibration or noise may be prevented.
The pivotable trailing edge can be designed in such a way that by means of pivoting the pivotable trailing edge the width of the air gap during extension of the lift-assisting flap from the retracted state to the extended state is at least at times kept constant or convergent. For example a control unit can be provided which during extension of the Fowler flap measures the corresponding gap and/or the width of the air gap and readjusts a drive for the pivotable trailing edge in such a way that the width of the air gap is kept constant or convergent.
The pivotable trailing edge can extend along the entire span width of the Fowler flap. As an alterative, the pivotable trailing edge can extend along only part of the span width of the Fowler flap.
The pivotable trailing edge can be attached to a housing of the main wing. In particular, the pivotable trailing edge can be attached to an upper section of the housing of the main wing.
The pivotable trailing edge can be attached to a moveable element which is attached to a housing of the main wing. In particular, the pivotable trailing edge can be attached to a spoiler which itself is attached to a housing of the main wing. Apart from the normal spoiler function, for which the spoiler is extended and thus moved, the spoiler can be operated in the retracted state in such a way that at an end section of the spoiler, which end section is on the rear of the wing, the pivotable trailing edge is formed which can be hinged across a predefinable angular range, so that a predefinable air gap width can be set precisely.
The pivotable trailing edge can be hinged by using a spring element.
As an alternative, the pivotable trailing edge can be swivelled by using a drive device which can, for example, be an electrical drive device or a hydraulic drive device.
Moreover, a vane (slat) can be provided on the aircraft wing, wherein in the extended state of the lift-assisting flap said vane is arranged between the main wing and the lift-assisting flap.
By using such a vane, an aircraft wing with a plurality of air gaps, in particular with two or three air gaps, can be formed.
In the extended state of the lift-assisting flap, several air gaps can be formed between the main wing and the lift-assisting flap.
The pivotable trailing edge is preferably designed in such a way that it is attached to the main wmg.
In the case of the aircraft wing the lift-assisting flap on the rear of the wing is preferably a Fowler flap. A Fowler flap is an element which can be moved to the rear below the trailing edge and which can be set at an angle. In this way an air gap (or several air gaps) can be formed between the topside and the buttomside of the wing, as a result of which the airfoil curvature is increased. At the same time the effective wing surface can also be increased.
According to the invention the width of the air gap is adjusted in that the pivotable trailing edge is hinged accordingly.
As an alternative, in the aircraft wing according to the invention the lift-assisting flap on the rear of the wing can be a slotted flap. In a slotted flap a control surface is tilted downward for extension. This movement simultaneously provides an air gap (or several air gaps), which admits (admit) air to the topside of the flap, thus preventing stalling. In a slotted flap the airfoil curvature is changed. According to the invention the width of the air gap is adjusted in that the pivotable trailing edge is swivelled accordingly.
l~
The invention can be applied not only to a Fowler flap or a slotted flap but to any lift-assisting flap in which in the extended state an air gap is created whose dimensions are to be controlled.
Embodiments of the invention are shown in the figures and are described in more detail below.
The following are shown:
Fig. 1 a main wing with a Fowler flap according to the state of the art;
Fig. 2 another Fowler flap on a main wing according to the state of the art;
Fig. 3 an aircraft wing according to a first embodiment of the invention;
Fig. 4 an aircraft wing according to a second embodiment of the invention;
Fig. S an aircraft wing according to a third embodiment of the invention;
Fig. 6 an aircraft wing according to a fourth embodiment of the invention; and Fig. 7A to Fig. 8B numeric flow simulations which show improved flow characteristics of the aircraft wing according to the invention.
Detailed Description of Exemplary Embodiments The drawings in the figures are diagrammatic and not to scale.
Identical or similar components in different figures have the same reference characters.
Below, with reference to Fig. 3, an aircraft wing according to a first embodiment of the invention is described.
Fig. 3 shows the aircraft wing according to the first embodiment of the invention in a retracted state 300 in which a Fowler flap 302 rests against the main wing 301, and in an extended state 310 in which the Fowler flap 302 forms an air gap 311 with the main wing 301.
Fig. 3 shows an aircraft wing with the main wing 301, the Fowler flap 302 and a pivotable trailing edge 304 of the main wing 301. The Fowler flap 302 is extendably attached to the main wing 301 (the corresponding coupling element is not shown in Fig. 3) and is equipped in such a way that in a retracted state 300 it rests against the main wing 301, and in an extended state 310 it forms an air gap 311 with the main wing 301. The pivotable trailing edge 304 is attached to an end section, more precisely to an end section on the rear of the main wing 301, and is pivotable in such a way that by pivoting the pivotable trailing edge 304 the width of the air gap 311 is adjustable.
Fig. 3 shows the pivotable trailing edge 304 in a first pivoted state 304a, in a second pivoted state 304b and in a third pivoted state 304c. The second hinged state 304b shows the end tip in its rest position. The first hinged state 304a shows an excursion of the end tip towards the top when compared to the rest position of the end tip. The third pivoted state 304c shows an excursion of the end tip towards the bottom compared to the rest position of the end tip.
Depending on the set pivoted state 304a to 304c, the width of the air gap 311 can be fine-adjusted, as a result of which undesirable airflow separations, vibration and noise in the aircraft interior are prevented. Furthermore, during the entire process of extension, i.e. during the transition from the state 300 to the state 310, the width of the air gap 311 can be directed or controlled.
The pivotable trailing edge 304 is pivotable in such a way that by pivoting the pivotable trailing edge 304 the width of the air gap 311 is held constant, namely during the transition of the Fowler flap 302 from the retracted state 300 to the extended state 310.
The pivotable trailing edge 304 extends in a direction perpendicular to the drawing plane in Fig. 3 along the entire span width of the Fowler flap 302. The pivotable trailing edge 304 is attached to an upper housing end section of the main wing 301 and is pivotable by a hydraulic drive unit (not shown).
Below, with reference to Fig. 4, an aircraft wing 400 according to a second embodiment of the invention is described.
The aircraft wing 400 shows a so-called "slotted flap", in other words a Fowler flap 302, which at a transition from the retracted state 300 to the extended state 310 only generates a single air gap. By using of a pivotable arm 401 the Fowler flap 302, by retraction and subsequent pivoting, is brought from state 300 to state 310. In order to make possible a constant width or convergence of the air gap between the Fowler flap 302 and the main wing 301 during this transition, a pivotable trailing edge 304 of the main wing 301 according to Fig. 4 is slightly moved from the top towards the bottom, e.g. using an electronic motor control system.
Below, with reference to Fig. 5, an aircraft wing 500 according to a third embodiment of the invention is described.
In the case of the aircraft wing S00 a spoiler 501 is provided on the topside of an end section on the rear of the main wing 301. If required, the spoiler 501 can be extended to influence the aerodynamic properties of the aircraft wing 500. Attached to an end section of the spoiler 501 is a pivotable trailing edge 304, which in Fig. 5 is shown in two different operating positions.
Fig. 5 shows a configuration with a "double slotted flap" so that two air gaps can be created.
To this effect a vane 502 is formed between the Fowler flap 302 and the main wing 301.
Below, with reference to Fig. 6, an aircraft wing 600 according to a fourth embodiment of the invention is described.
In a way similar to that of the aircraft wing 500, the aircraft wing 600 comprises a "double slotted flap" and has a configuration in which a main wing 301, a vane 302 and a Fowler flap 302 form a first air gap 601 and a second air gap 602, respectively. An end section of the main wing 301 again comprises a pivotable trailing edge 304, which when the Fowler flap 302 makes the transition from the retracted state to an extended state is moved from state 300 to state 310. In other words, state 300 depicts a baseline state of the pivotable trailing edge 304, while state 310 shows an end state of the pivotable trailing edge 304 in a position of maximum excursion.
Below, with reference to Figs 7A to 8B it is illustrated that with the use of the aircraft wing 600 the aerodynamic characteristics are significantly improved. Figs 7A to 8B
show computational fluid dynamics (CFD) simulations, i.e. numeric flow simulations, in which the eddy viscosity in a region surrounding an aircraft wing is graphically shown.
The CFD
simulations of Figs 7A to 8B have been calculated with an (unstructured) process using Navier-Stokes equations.
Figs 7A and 8A show the flow characteristics of an aircraft wing without the pivotable trailing edge according to the invention. Figs 7B and 8B show the improved flow characteristics when providing a pivotable trailing edge 304.
Figs 7A, 7B show that according to the invention, flow separation at medium angles of extension of the Fowler flap 302 (for example 35°) is strongly suppressed. Furthermore, Figs 8A and 8B show the improvement according to the invention of the flow characteristics in a region surrounding the flap 302 at a large angle of extension (for example 50°).
It should be noted that the term "comprising" does not exclude other elements or steps and the "a" or "an" does not exclude a plurality. Also elements described in association with different embodiments may be combined. It should also be noted that reference signs in the claims shall not be construed as limiting the scope of the claims.
Claims (14)
1. An aircraft wing comprising: a main wing having a housing; a spoiler, wherein the spoiler is attached to the housing of the main wing; a pivotable trailing edge, wherein the pivotable trailing edge is pivotably attached to the spoiler; and a lift-assisting flap on the rear of the main wing;
wherein the lift-assisting flap is coupled to the main wing and is designed in such a way that in a retracted state, the lift-assisting flap abuts the main wing and in an extended state, the lift-assisting flap forms an air gap with the main wing; and the pivotable trailing edge is pivotable in such a way that by pivoting the pivotable trailing edge, a shape and a width of the air gap are adjustable.
wherein the lift-assisting flap is coupled to the main wing and is designed in such a way that in a retracted state, the lift-assisting flap abuts the main wing and in an extended state, the lift-assisting flap forms an air gap with the main wing; and the pivotable trailing edge is pivotable in such a way that by pivoting the pivotable trailing edge, a shape and a width of the air gap are adjustable.
2. The aircraft wing of claim 1, wherein the pivotable trailing edge is pivotable in such a way that by pivoting the pivotable trailing edge the width of the air gap is kept constant or convergent.
3. The aircraft wing of claim 1, wherein the pivotable trailing edge is pivotable in such a way that by pivoting the pivotable trailing edge the width of the air gap during extension of the lift-assisting flap from the retracted state to the extended state is at least at times kept constant or convergent.
4. The aircraft wing of claim 1, wherein the pivotable trailing edge extends along an entire span width of the lift-assisting flap.
5. The aircraft wing of claim 1, wherein the pivotable trailing edge extends along part of the span width of the lift-assisting flap.
6. The aircraft wing of claim 1, wherein the pivotable trailing edge is pivotable by using a spring element.
7. The aircraft wing of claim 1, wherein the pivotable trailing edge is pivotable by using a drive device.
8. The aircraft wing of claim 7, wherein the drive device is: an electrical drive device; or a hydraulic drive device.
9. The aircraft wing of claim 1, further comprising: a vane which in the extended state of the lift-assisting flap is arranged between the main wing and the lift-assisting flap.
10. The aircraft wing of claim 1, wherein in the extended state of the lift-assisting flap, several air gaps are formed between the main wing and the lift-assisting flap.
11. The aircraft wing of claim 1, wherein the lift-assisting flap on the rear of the wing is a Fowler flap.
12. The aircraft wing of claim 1, wherein the lift-assisting flap on the rear of the wing is a slotted flap.
13. A method for operating an aircraft main wing, the method comprising:
attaching a pivotable trailing edge to a spoiler; attaching the spoiler to a housing of the main wing, extendably;
moving a lift-assisting flap coupled to the main wing from a retracted state in which the lift-assisting flap abuts the main wing to an extended state in which the lift-assisting flap forms an air gap with the main wing; and swivelling the pivotable trailing edge such that pivoting the pivotable trailing edge adjusts a shape and a width of the air gap.
attaching a pivotable trailing edge to a spoiler; attaching the spoiler to a housing of the main wing, extendably;
moving a lift-assisting flap coupled to the main wing from a retracted state in which the lift-assisting flap abuts the main wing to an extended state in which the lift-assisting flap forms an air gap with the main wing; and swivelling the pivotable trailing edge such that pivoting the pivotable trailing edge adjusts a shape and a width of the air gap.
14. A method comprising: controlling the aircraft wing of claim 1, such that the pivotable trailing edge is pivoted and the shape and the width of the air gap between the main wing and the pivotable trailing edge is adjusted.
Applications Claiming Priority (4)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US61805104P | 2004-10-11 | 2004-10-11 | |
| DE102004049504.1 | 2004-10-11 | ||
| DE102004049504A DE102004049504A1 (en) | 2004-10-11 | 2004-10-11 | Wing for aircraft has a rear auxiliary lift flap coupled to main wing and able to lie against main wing in retracted position and form air gap with it when extended |
| US60/618,051 | 2004-10-11 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CA2522553A1 CA2522553A1 (en) | 2006-04-11 |
| CA2522553C true CA2522553C (en) | 2010-09-21 |
Family
ID=35447758
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA2522553A Expired - Fee Related CA2522553C (en) | 2004-10-11 | 2005-10-07 | Aircraft wing, method for operating an aircraft wing, and use of a pivotable trailing edge on a main wing of an aircraft, for adjusting the shape and the width of an air gap |
Country Status (4)
| Country | Link |
|---|---|
| EP (1) | EP1645503B9 (en) |
| AT (1) | ATE390348T1 (en) |
| CA (1) | CA2522553C (en) |
| DE (1) | DE502005003434D1 (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE102009057340A1 (en) | 2009-12-07 | 2011-06-09 | Airbus Operations Gmbh | High lift system for an aircraft, method of moving a lift flap, and aircraft with a high lift system |
Family Cites Families (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR728528A (en) * | 1931-02-28 | 1932-07-07 | Support surfaces of flying machines and the like | |
| US3767140A (en) * | 1971-11-03 | 1973-10-23 | Mc Donnell Douglas Corp | Airplane flaps |
| DE3621401C1 (en) * | 1986-06-26 | 1988-01-14 | Messerschmitt Boelkow Blohm | Flap arrangement for an aircraft mainplane (wing) |
| US4784355A (en) * | 1986-11-10 | 1988-11-15 | The United States Of America As Represented By The Secretary Of The Air Force | Flap system for short takeoff and landing aircraft |
| CN1184056A (en) * | 1996-11-29 | 1998-06-10 | 三星航空产业株式会社 | Airfoil of aircraft |
-
2005
- 2005-10-07 CA CA2522553A patent/CA2522553C/en not_active Expired - Fee Related
- 2005-10-11 AT AT05022131T patent/ATE390348T1/en not_active IP Right Cessation
- 2005-10-11 EP EP05022131A patent/EP1645503B9/en not_active Not-in-force
- 2005-10-11 DE DE502005003434T patent/DE502005003434D1/en active Active
Also Published As
| Publication number | Publication date |
|---|---|
| CA2522553A1 (en) | 2006-04-11 |
| EP1645503B1 (en) | 2008-03-26 |
| ATE390348T1 (en) | 2008-04-15 |
| EP1645503B9 (en) | 2008-09-24 |
| EP1645503A1 (en) | 2006-04-12 |
| DE502005003434D1 (en) | 2008-05-08 |
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