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

Abstract

An air to air refueling system that monitors and adapts the movement at an end of an air to air refueling hose of a tanker aircraft to counteract undesirable movements at the end of the hose though generating aerodynamic loads in the end of the hose. The system includes grid fins at the end of the hose that are automatically rotated to counteract the undesirable movements.

Claims

1. An air to air active refueling system for a tanker aircraft, the system comprising: a hose configured to convey fuel from the tanker aircraft to a receiver aircraft and including a hose-end; a coupling at the hose-end and comprising a drogue, the coupling is configured to be coupled to a receiver probe of the receiver aircraft in an air-to air refueling operation, a hose-end control unit at the hose-end including: at least three grid fins each mounted to a respective fin shaft and configured to fold and deploy, wherein each of the grid fins are configured to rotate about an axis of the fin shaft; an inertial measurement unit configured to measure an acceleration of the hose-end; a first sensor configured to sense a relative position between the first sensor and the receiver probe of the receiver aircraft; and a processing unit configured to receive measurements of the acceleration of the hose-end made by the inertial measurement unit, receive the relative position sensed by the first sensor, determine one or more desired deflection angles for rotation of one or more of the grid fins based on the measurements of the acceleration and the relative position, and actuate the one or more grid fins to rotate the one or more desired deflection angles.

2. The air to air active refueling system according to claim 1, wherein the hose end control unit further comprises: a fix frame arranged along the longitudinal axis and mechanically connecting the hose to the coupling, and a rotary frame rotationally connected to the fix frame and comprising the fin shafts extending outward from the rotary frame, and wherein the rotary frame is rotatable about a longitudinal axis of the of the hose end control unit.

3. The air to air active refueling system according to claim 2, wherein the rotary frame is mounted over the fix frame, wherein bearings between the rotary frame and the fix frame allow the rotatory frame to rotate around the longitudinal axis.

4. The air to air active refueling system according to claim 1, wherein the grid fins are at least four grid fins, and each of the grid fins are arranged about the longitudinal axis at intervals of ninety degrees.

5. The air to air active refueling system according to claim 1, wherein the hose control unit further comprises at least one actuator configured to rotate one or more of the grid fins, wherein the at least one actuator is configured to rotate the grid fins by the desired deflection angle corresponding to the respective grid fin.

6. The air to air active refueling system according to claim 5, wherein each of the fin shafts are supported by fin shaft bearings and mechanically connected to the at least one actuator.

7. The air to air active refueling system according to claim 5, wherein the at least one actuator includes a second sensor configured to sense a deflection angle of the at least one grid fin associated with the at least one actuator.

8. The air to air active refueling system according to claim 1, wherein the hose control unit further comprises a folding mechanism configured to fold and deploy each of the at least three grid fins.

9. The air to air active refueling system according to claim 8, wherein the folding mechanism comprises a retraction mechanism for the at least three grid fins.

10. The air to air active refueling system according to claim 8, wherein the folding mechanism is independent of an actuator configured to rotate the at least three grid fins.

11. The air to air active refueling system according to claim 1, wherein the first sensor is located at the hose-end and is configured to measure a relative position between the hose-end and a receiver probe of the receiver aircraft.

12. The air to air active refueling system according to claim 1, wherein the first sensor includes a sensor located on the tanker aircraft and configured to measure a relative position between the tanker aircraft and the receiver probe of the receiver aircraft.

13. A tanker aircraft comprising the air to air active refueling system according to claim 1.

14. A hose and drogue air to air refueling system comprising: a hose configured to be mounted to a tanker aircraft and convey fuel from the tanker aircraft to a receiver aircraft; a drogue coupling attached to a distal end of the hose at the hose-end, wherein the drogue coupling is configured to connect to a receiver probe of the receiver aircraft; a hose-end control unit at the distal end of the hose wherein the hose-end control unit comprises: a frame having a longitudinal axis which extends through the drogue coupling, and at least three fins each mounted to the frame and extending outward from the frame, wherein each of the three fins is configured to by dynamically rotated by a respective deflection angle; an inertial measurement unit configured to measure an acceleration of at least one of the hose-end and drogue coupling; a first sensor configured to sense a relative position between the first sensor and the receiver probe of the receiver aircraft; and a processing unit configured to receive acceleration measurements from the inertial measurement unit, receive the relative position sensed by the first sensor, determine one or more desired deflection angles for rotation of one or more of the fins based on the measurements of the acceleration and the relative position, and actuate the one or more fins to rotate the one or more desired deflection angles.

15. A method for compensating for aerodynamic radial loads applied to a drogue of a hose and drogue air to air active refueling system, the method comprising: deploying a refueling hose from a tanker aircraft, wherein a 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; automatically sensing acceleration of the hose end control unit and/or the drogue coupling, and generating an acceleration signal with data indicating the sensed acceleration; automatically determining at least one deflection angle for at least one of the three fins based on the sensed acceleration, and automatically rotating at least one of the three fins by the at least one deflection angle.

16. The method according to claim 15, further comprising: sensing a position of a receiver probe approaching the drogue and the step of determining the at least one deflection angle includes determining the at least one deflection angle based on the position.

17. The method according to claim 15, wherein the sensing of the acceleration and determination of the at least one deflection angle are performed in real-time, and the step of automatically rotating the at least one of the three fins is performed repeatedly and in real time.

18. The method according to claim 15, wherein the step of automatically rotating the at least one of the three fins includes determining the at least one deflection angle to counteract accelerations at the distal end of the hose.

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 fix frame (6.1) and a rotary frame (6.2)

[0084] The fix 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 fix 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 fix 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 (α) (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 (α) 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 (α) 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 (α) 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 (α) 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 (α) 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 (α) 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 (α) 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 (α) 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.