AIR TO AIR ACTIVE REFUELING SYSTEM AND METHOD FOR GENERATING AERODYNAMIC RADIAL LOADS AT A HOSE-END

Abstract

A method for compensating for aerodynamic radial loads applied to a drogue coupling of a hose and drogue air to air active refueling system including: deploying a refueling hose from a tanker aircraft, wherein the drogue coupling is at a distal end of the hose and the drogue coupling is connected to a hose end control unit which includes at least three fins extending outward into air flowing over the hose end control unit; sensing acceleration of the hose end control unit and/or the drogue coupling, generating an acceleration signal with data representing the sensed acceleration; determining at least one deflection angle for at least one of the three fins based on the acceleration signal, and rotating at least one of the three fins by the at least one deflection angle.

Claims

1. A method for compensating for aerodynamic radial loads applied to a drogue coupling of a hose and drogue air to air active refueling system, the method comprising: deploying a refueling hose from a tanker aircraft, wherein the drogue coupling is at a distal end of the hose and the drogue coupling is connected to a hose end control unit which includes at least three fins extending outward into air flowing over the hose end control unit; sensing acceleration of the hose end control unit and/or the drogue coupling, generating an acceleration signal with data representing the sensed acceleration; determining, based on the acceleration signal, at least one deflection angle for at least one of the three fins to reduce an aerodynamic load applied to the drogue coupling and/or the hose end control unit, and rotating at least one of the three fins by the at least one deflection angle.

2. The method of claim 1, further comprising determining, based on the acceleration signal, the aerodynamic radial force applied to the hose end control unit and/or the drogue coupling, wherein the step of rotating the at least one of the three fins reduces the radial aerodynamic load.

3. The method of claim 1, wherein the rotating of the at least one of the three fins is performed by the hose end control unit.

4. The method according to claim 1, further comprising: sensing a position of a receiver probe relative to the drogue coupling, and the step of determining the at least one deflection angle includes determining the at least one deflection angle based on the sensed position and the sensed acceleration.

5. The method according to claim 1, wherein the steps of sensing of the acceleration, generating the acceleration signal, determining the at least one deflection angle and the rotation of the at least one of three fins are performed in real time and repeatedly.

6. The method according to claim 1, wherein the step of determining the at least one deflection angle includes determining a deflection angle to counteract the sensed acceleration.

7. The method according to claim 1, wherein the step of determining the at least one deflection angle includes determining the deflection angle to reduce the sensed acceleration.

8. The method according to claim 1, further comprising: determining a radial load on the drogue due to the acceleration, and the determining of the at least one deflection angle includes determining the deflection angle to reduce the radial load.

9. A method for air-to-air refueling comprising: deploying a refueling hose from a tanker aircraft, wherein the refueling hose includes at distal portion including a hose end and hose control unit, and the hose control unit includes a moveable aerodynamic surface extending into an airflow over the hose control unit; sensing an acceleration associated with the distal portion; determining an aerodynamic force applied to the distal portion based on the sensed acceleration, determining a movement to be applied to the aerodynamic surface to reduce the aerodynamic force, and moving the aerodynamic surfaces in accordance with the determine movement.

10. The method for air-to-air refueling of claim 9, further comprising connecting the hose end to a receiver probe of a receiver aircraft during the step of moving the aerodynamic surface.

11. The method for air-to-air refueling of claim 10, wherein the aerodynamic surface includes a rotatable fin extending outward from the hose control unit, and the movement is a rotation of the fin.

12. The method for air-to-air refueling of claim 9, further comprising: sensing a relative position of a receiver probe of a receiver aircraft relative to the hose end unit and/or hose end, and the step of determining the movement includes determining the movement based on the relative position and to reduce the aerodynamic force.

13. The method for air-to-air refueling according to claim 9, wherein the steps of sensing of the acceleration, determining the aerodynamic force, determining the movement, and the moving the aerodynamic surface are performed in real time and repeatedly.

14. The method for air-to-air refueling according to claim 9, wherein the step of determining the movement includes determining the movement to counteract the sensed acceleration.

15. The method for air-to-air refueling according to claim 9, wherein the determination of the aerodynamic force is a determination of a radial aerodynamic force applied to the hose end and/or hose end control unit due to the sensed acceleration, and the determining of the movement includes determining the movement to reduce the radial aerodynamic force.

16. A method for air-to-air refueling comprising: deploying a refueling hose from a tanker aircraft, wherein the refueling hose includes at distal portion including a hose end and hose control unit, and the hose control unit includes a moveable aerodynamic surface extending into an airflow over the hose control unit; sensing a radial aerodynamic force applied radially to the distal portion of the deployed refueling hose; determining a movement for the aerodynamic surface to reduce the radial aerodynamic force; moving the aerodynamic surface relative to the airflow based on the determined movement; connecting the hose end to a receiver probe of a receiver aircraft, and delivering fuel to the receiver aircraft from the refueling hose, through the hose end and into the receiver probe.

17. The method for air-to-air refueling of claim 16, wherein the aerodynamic surface is a rotatable fin extending outward from the hose control unit, and the movement is a rotation of the fin.

18. The method for air-to-air refueling of claim 16, further comprising: sensing a relative position of the receiver probe of the receiver aircraft relative to the hose end unit and/or hose end, and the step of determining the movement includes determining the movement based on the relative position and to reduce the radial aerodynamic force.

19. The method for air-to-air refueling according to claim 16, wherein the steps of sensing of the acceleration, determining the movement, and the moving the aerodynamic surface are performed in real time and repeatedly.

20. The method for air-to-air refueling according to claim 16, wherein the step of determining the movement includes determining the movement to counteract the force.

Description

SUMMARY OF FIGURES

[0071] These and other characteristics and advantages of the invention will become clearly understood in view of the detailed description of the invention which becomes apparent from a preferred embodiment of the invention, given just as an example and not being limited thereto, with reference to the drawings.

[0072] FIG. 1 is a side view of an air to air active refueling system of a tanker aircraft approaching to a receiver aircraft according to an embodiment of the present invention.

[0073] FIG. 2 is a top-down view of the embodiment shown in FIG. 1.

[0074] FIG. 3 is a side view of a hose of an air to air active refueling system according to an embodiment of the present invention.

[0075] FIG. 4 is a perspective view of a hose-end of an air to air active refueling system according to an embodiment of the present invention.

[0076] FIG. 5 is a side view of the hose-end of an air to air active refueling system according to an embodiment of the present invention.

[0077] FIG. 6 is an end view of a hose control unit (HCU) having four grid fins of an air to air active refueling system according to an embodiment of the present invention.

[0078] FIG. 7 is a schematic diagram of components of an air to air active refueling system according to an embodiment of the present invention.

DETAILED DESCRIPTION

[0079] FIGS. 1 and 2 show a side and an upper view respectively of an air to air active refueling system (1) in a refueling operation between a tanker aircraft (2) and a receiver aircraft (3). In particular, these figures show the hose (4) of the air to air active refueling system (1) is in an extended position out of a tanker aircraft (2) and the receiver aircraft approaching to this hose (4). The air to air active refueling system (1) comprises a hose (4) for driving fuel from a tanker aircraft (2) to a receiver aircraft (3) in a refueling operation. Said hose (4) presents a drogue (5) located at a hose-end (4.1) suitable for being coupled with a probe (13) of the receiver aircraft (3). The hose (4) also comprises another end (4.2) opposite to the already mentioned hose-end (4.1) where the hose (4) is fixed to the tanker aircraft (2). In a refueling operation, the refueling system (1) installed on the tanker aircraft (2) extends the hose (4) in order to couple the drogue (5) of the hose-end (4.1) to the probe (13) of the receiver aircraft (3) that is flying closer to the tanker aircraft (2) for allowing the approaching of the drogue (5) towards the probe (13). Once the coupling is achieved, then the fuel starts being driven through the hose (4) from the tanker aircraft (2) towards the receiver aircraft (3).

[0080] FIG. 3 shows a schematic side view of a portion of a hose (4) of an air to air active refueling system (1). The hose (4) comprising a hose-end (4.1) suitable for coupling the air to air active refueling system (1) to a probe (13) of the receiver aircraft (3) (as shown in FIGS. 1 and 2) by monitoring and generating aerodynamic radial loads at the hose-end (4.1) in order to adapt the movement at the end of the hose (4) while approaching the probe (13) of the receiver aircraft (3). The hose-end (4.1) comprises a drogue (5) and a coupling (8), the drogue (5) is arranged through the coupling (8) and is the component of the refueling system (1) that is directly coupled to a probe (13) of a receiver aircraft (3) in refueling operations, as shown in FIGS. 1 and 2.

[0081] According to FIG. 3, the hose-end (4.1) also comprises a Hose Control Unit (HCU) (6) configured to reduce aerodynamic radial loads at the end of the hose (4) due to flight conditions of the refueling system (1) in a refueling operation. The HCU (6) is located between the hose (4) and the coupling (8). Said HCU (6) shows three grid fins (7) in a deployed state. These grid fins (7) can be folded or deployed following the need of adapting the movement of the hose-end (4.1) in a refueling operation. The grid fins (7) are deployed from the HCU (6) towards outside this HCU (6).

[0082] FIGS. 4 and 5 show p examples of an air to air active refueling system (1). Particularly, FIG. 4 shows a perspective view of a hose-end (4.1) of the refueling system (1) in detail and FIG. 5 shows a side view of another hose-end (4.1) in detail of a refueling system (1).

[0083] Both refueling systems (1) of FIGS. 4 and 5 comprise a HCU (6) located at the hose-end (4.1) and comprising a fixed frame (6.1) and a rotary frame (6.2).

[0084] The fixed frame (6.1) is arranged along a longitudinal axis (X) around the hose (4) at the hose-end (4.1) and the rotatory frame (6.2) is rotationally connected to the fixed frame (6.1). Said rotary frame (6.2) is configured to rotate around the same longitudinal axis (X) and provide adaptation to in-flight conditions. In FIG. 4, the HCU (6) shows four grid fins (7) located on the rotatory frame (6.2) and in a deployed state. FIG. 5 shows a rotary frame (6.2) with three grid fins (7) in a deployed state and fin shafts (10) on which one grid fin (7) is respectively fixed on each fin shaft (10). Specifically, the rotation of the rotatory frame (6.2) around the longitudinal axis (X) allows the free rotation of the plurality of grid fins (7) given that the grid fins (7) are fixed to the rotatory frame and their respective fin shafts (10) (according to FIG. 5) are also mounted on said rotatory frame (6.2).

[0085] FIGS. 4 and 5 further shows a coupling (8) mechanically connected to the hose (4) through the fixed frame (6.1) along the longitudinal axis (X). Said coupling (8) is responsible for forwarding the hose (4) to the drogue (5) and ensure the fuel arrival at a drogue (5) also located at the hose-end (4.1) of the refueling system (1). Said drogue (5) is arranged for connecting the hose-end (4.1) to the probe (13) of a receiver aircraft (3) (shown in FIGS. 1 and 2) to confer autonomy and assistance to the receiver aircraft (3) for the approach maneuver in a refueling operation. Particularly, during the contact coupling is configured to support axial and radial loads transmitted by the receiver aircraft (3). The contact will be understood as the time in which the drogue (5) of the tanker aircraft (2) contacts with the probe (13) of the receiver aircraft (3) (after the moment shown in FIGS. 1 and 2). Therefore, during the contact in a refueling operation the HCU (6) performs an active control of the axial forces transmitted between the receiver probe (13) and the coupling (8) by generating additional drag force. This additional drag force (aerodynamic radial loads) is provided by the actuation of a deflection angle (a) (shown in FIG. 6) in each grid fin (7) independently and the rotation of these grid fins (7). Thus, these aerodynamic radial loads at the hose-end (4.1) help to keep the force balance in contact between the tanker aircraft (2) and the receiver aircraft (3), in addition to drogue tension control and coupling latching forces, in a refueling operation.

[0086] As it can be observed in FIG. 5, the rotatory frame (6.2) comprises gaps (6.2.1) which are suitable for housing the grid fins (7) inside said rotary frame (6.2) when these grid fins (7) are in a folded state.

[0087] FIG. 6 shows a schematic view of an example of a rotatory frame (6.2) of an HCU (6), this view corresponding to a cross-sectional view to longitudinal axis (X) or the hose (4) of an air to air active refueling system (1). Particularly, it is shown four grid fins (7) in a deployed state and mounted on the rotatory frame (6.2) of the HCU (6). Each grid fin (7) is respectively mechanically connected to this rotatory frame (6.2) by a fin shaft (10). In particular, the fin shafts (10) are separated by 90° from each other respecting the longitudinal axis (X).

[0088] Each grid fin (7) can be actioned by an actuator (not shown in figures) responsible for the deflection of each grid fin (7) independently of the others and with respect to their fin shaft (10) based on the processed information and required adaptation to in-flight conditions. The fin shaft (10) provides to each grid fin (7) the independent rotation that facilitate the adaptation of the desired aerodynamic radial loads at the hose-end (4.1) and ensure the connection of the drogue (5) with the probe (13) of the receiver aircraft (3) in a refueling operation. Particularly, the independent rotation of each grid fin (7) corresponds to adapting the deflection angle (a) of these grid fins (7).

[0089] FIG. 7 shows an architecture model of some of the components that collaborate in the provision of aerodynamic radial load at the hose-end (4.1) of an air to air active refueling system (1). This refueling system (1) comprises at least an HCU (6) comprising a plurality of grid fins (7) for generating radial loads at the hose-end (4.1) by deploying the plurality of grid fins (7) and actuating on their deflection angle (a) and their rotation around a longitudinal axis (X) to adapt to the in-flight conditions. The HCU (6) further comprises and IMU (9) for measuring the acceleration at the hose-end (4.1). The refueling system (1) also comprises first sensing means (12) that can be located on the hose-end (4.1) or on the tanker aircraft (2) when the refueling system (1) in operative mode is installed on said tanker aircraft (2). The first sensing means (12) measures the relative position between the hose-end (4.1) and a receiver aircraft (3) or between the tanker aircraft (2) and the receiver aircraft (3) respectively. Additionally, the refueling system (1) comprises a processing unit (11) in data connection with the HCU (6) and the first sensing means (12). This processing unit (11) processes the measurements from the IMU (9) and the first sensing means (12), and according to the processed information about the measurements, the processing unit (11) is configured send comments, e.g., data, to the HCU (6) to enable the HCU to generate the aerodynamic radial loads predefined according to the refueling system (1) needed in a refueling operation. The processing unit (11) can be located on the hose-end (4.1) or on a tanker aircraft (2) when the refueling system (1), in an operative mode, is installed on the tanker aircraft (2).

[0090] The invention may be embodied as a method for generating aerodynamic radial loads at a hose-end (4.1) (shown in FIGS. 1-6) of an air to air active refueling system (1) and comprises at least the following steps: a) configuring the deflection angle (a) of each grid fin (7) located at the HCU (6), and b) rotating the plurality of fins (7) by means of the actuation of the HCU (6), wherein both the configuration of the deflection angles (a) and the rotation of the plurality of the grid fins (7) are based on measurements processed by the processing unit (11) of the system (1).

[0091] In a refueling operation, the IMU (9) located on the HCU (6) measures a linear acceleration and angular acceleration at one point of the hose-end (4.1) and send (step c) these measurements to the processing unit (11). In addition, the first sensing means (12) located, for example, on the hose-end (4.1) measure the relative position between the probe (13) of a receiver aircraft (3) and the location of the first sensing means (12) on the hose-end (4.1) of the tanker aircraft (2), and this relative position measurement is also sent (step d) to the processing unit (11). Both steps c) and d) are carried out before the mentioned steps a) and b).

[0092] Once the processing unit (11) received information at least from the IMU (9) and the first sensing means (12), the processing unit (11) processes this information and is able to determine the aerodynamic radial loads needed at the hose-end (4.1). Therefore, according to this predetermined needed, the processing unit (11) commands the HCU (6) to actuate, according to step a), the deflection angle (a) of each grid fin (7) and, according to step b), the rotation of all the grid fins (7) by means of the rotation of the rotatory frame (6.2) of this HCU (6). The processing unit (11) is further able to process the information coming from the IMU (9) and first sensing means (12) and to determine the deflection angle (a) configuration for each grid fin (7) and the velocity of rotation of the rotary frame (6.2) of the HCU (6) for generating the aerodynamic radial load needed at the hose-end (4.1) in the approach to the coupling between the drogue (5) of the tanker aircraft (2) and the probe (13) of the receiver aircraft (3).

[0093] The processing unit (11) is also able to provide folding/deploying actuation of said plurality of grid fins (7) by means of a folding mechanism (not shown in figures) located on the HCU (6). The deploying actuation is performed prior to configure the deflection angle (a) of each grid fin (7) and also prior to rotate these grid fins (7). However, the folding actuation is performed after the generation of aerodynamic radial loads by the actuation of the HCU (6).

[0094] Moreover, the processing unit (11) can be connected to an aircraft control equipment, such as a controller located on the aircraft, so that this control equipment determines the aerodynamic radial loads needed at the hose-end (4.1) instead of the processing unit (11) and sends to the HCU (6) instructions to configure the deflection angle (a) of each grid fin (7) and to rotate these grid fins (7)).

[0095] While at least one exemplary embodiment of the present invention(s) is disclosed herein, it should be understood that modifications, substitutions and alternatives may be apparent to one of ordinary skill in the art and can be made without departing from the scope of this disclosure. This disclosure is intended to cover any adaptations or variations of the exemplary embodiment(s). In addition, in this disclosure, the terms “comprise” or “comprising” do not exclude other elements or steps, the terms “a” or “one” do not exclude a plural number, and the term “or” means either or both. Furthermore, characteristics or steps which have been described may also be used in combination with other characteristics or steps and in any order unless the disclosure or context suggests otherwise. This disclosure hereby incorporates by reference the complete disclosure of any patent or application from which it claims benefit or priority.