BE1025446B1 - AERONEF BOMBARDIER OF WATER - Google Patents

Abstract

The invention relates to an airborne fire-fighting tank called hydrone, towed by a cargo plane, capable of bailing on a relatively agitated body of water at the speed required by the tractor. A module overflowing with traction and control is loaded in the cargo hold of the cargo plane. The pull cable is pull down to allow more precise approach to fire. The hydrone is composed of a fuselage fuselage allowing to penetrate by "slice" the plan of water. The scoop holes are located in the bottom of the slice. Curvature piping accelerates the water and discharges it into the tanks in the most laminar way possible.

Description

WATER BOMBARDIER AIRCRAFT

Technical Field [0001] The present invention essentially relates to the fight against wildfires by dropping water, by air.

State of the art [0002]

Airborne firefighting means mainly include helicopters and airplanes, including conventional airplanes and seaplanes.

Helicopters carry limited amounts of load and the release is done at low speeds, which is not optimal.

The seaplane is the most suitable aeronautical architecture since the reloading is done very quickly, by dynamic scooping, on a water surface, not dependent on the conditions of an airport. Unfortunately, the seaplane architecture is today abandoned by the aeronautical industry. Consequently, the search for specific solutions against fires is not a profitable priority for manufacturers. Unsuccessful concepts exist for towed aircraft [Haas J. T., DE 40 32 672 A 1, 1992]

BE2017 / 5540 [0005] Conventional aircraft can be transformed into a water bomber or other liquid, from the single-engine single-engine aircraft to the four-jet engine [B-747 Evergreen].

Most often these are adaptations made on old aircraft whose operational efficiency is discussed [Evaluation of the effectiveness of the 10 tanker air carrier DC-10 Air Tanker, Victoria 2010, MP Plucinski, Bushfire Dynamics and Applications , CSIRO, Canberra, Australia]. The major defect remains the duration of the recharging procedure which prevents the high rotations required by serious situations. However, studies relating to climate change would tend to show that the intensity of fires could increase in the future. Urbanization in risk areas also increases the economic impact of this risk.

The pair flight combining a tractor plane and a towed plane, in addition to the leisure flight of light gliders, was widely developed during the Second World War. The most widespread architecture during airborne military operations during this period included a twin or four-engine bomber in the function of tractor aircraft and a transport glider generally designed as a consumable for a single mission. Traction and flight technologies remained rudimentary. The maneuvers were not much more complex than those practiced when towing recreational gliders. The relevance and efficiency of towing was nevertheless demonstrated on a large scale for critical operations.

BE2017 / 5540

Disclosure of the invention The object of the present invention is to provide a new tool for fighting fires, based on conventional aeronautical solutions, but with the advantages of the seaplane.

The invention can however be applied for other purposes, for example the spreading of liquid products, generally water-based, on crops or wooded surfaces. Products in the form of powders can also be envisaged.

The present invention consists of a flying tank provided with a dedicated scooping system, all of which can be towed by a conventional aircraft and, if necessary, operated from it.

Towing rather than motorization of the flying tank makes it possible to limit operational costs as well as the financial risk in the event of loss of the tank in an operating situation.

In a towed architecture, the tractor aircraft will preferably be an aircraft having a free interior volume as well as a rear exit ramp proportional to the volume. Military propeller transport aircraft constitute the type of aircraft most suited to the towing function relating to the present invention.

In a towed architecture, a removable device ready for use for towing and

BE2017 / 5540 remote control of the flying tank will be placed and fixed in the hold of the towing aircraft.

In a towed architecture, the flying tank becomes a glider connected to the tractor during the entire operation. The glider is only released in the final landing phase, after contact with the ground is assured.

The flying tank is the main element of the present invention. It will be called HYDRONE, whatever the architecture: motorized or towed, with or without an on-board pilot. The unmanned option on board is nevertheless preferable given the usual dangerousness of any firefighting operation, as well as the scooping operation.

The hydrone is provided with a member allowing scooping without the maneuver related to a ditching. Scooping is only a drawing in the case of the present invention. The shape of the scooping member is the "slice", allowing vertical and progressive penetration into the water. The hydrone will only be able to land in the event of a major emergency, involving the break in connection with the towing aircraft.

The following description of the present invention relates to the towed architecture. The motorized hydrone is a simplified case of the present invention.

This description is provided only by way of nonlimiting example of an embodiment of the invention.

BE2017 / 5540

Brief description of the drawings [0016] Figure 1: assembly on board in the hold of the tractor aircraft.

Figure 2, 3 and 4: towed glider called hydrone.

Figure 5: Scooping device and tanks.

Figure 6: scooping head.

Figure 7, 8 and 9: arming the towing aircraft.

Figure 10 and 11: takeoff phases.

figure 12: cruise flight figure 13: scooping. figure 14: landing. figure 15: flight procedure figure 16: instruments of

or aligned.

ledge.

flight specific to pair flight.

Implementation of the invention

A. On-board system (2) in the tractor airplane [0017] A self-supporting metallic structure (trellis) (2a) constitutes the main support of the on-board elements (2) allowing the cargo airplane (1) to be adapted to use for towing the hydrone (3).

This removable structure (2) is brought then fixed "plug and play" on the existing attachment systems, or possibly reinforced, in the hold of the tractor aircraft (1). It is removed at the end of the mission, in a completely reversible manner.

BE2017 / 5540 This structure (2a) transfers, in overhang, the large tensile forces exerted at the rear towards the center of gravity of the tractor.

It is designed to tow heavier loads than those of the state of the art and to allow aerial maneuvers required in dropping operations.

In the front part of the structure is fixed a cable reel capacity adapted to the length of the chosen cable.

The winding device (2b) is provided with a speed sensor (winding, unwinding) as well as a winding state counter, a winding motor, a unwinding brake , an emergency cable release system (disconnector or other).

The traction cable (2g) runs through the structure towards the rear, guided by a guide rail, in a protective chute.

The cable (2g) leaves the structure at the rear end (2f), under the cockpit, and passes through a winding stop device, operating when the cable must be completely brought back into the tractor, for example after landing of the hydrone, as well as a crutch capable of supporting the assembly (2h) of damping, rigid linearly, and of attachment to the end of said cable.

BE2017 / 5540 The hydrone cockpit (2c), equipped for two pilots (2d), is placed at the rear end of the supporting structure, and thanks to a bay window (2e) a wide field of vision on the operating frames for scooping and for bombing.

The hydrone is controlled in a conventional manner by telecommunication means.

A tailor-made wall of the tractor aircraft, flexible or semi-rigid, confines the cockpit and closes the rear gap in the hold of the tractor aircraft by marrying the edges of the open tailgate.

B. Traction cable and attachment of the hydrone The hydrone traction point (3e) will be located above the fuselage, substantially in the direction of the center of gravity and the scooping piping curve (3d , 3k), for the nominal traction angle used in the scooping phase, in order to create a lifting effect by the cable (2g) itself. An increase in the attachment point by a pylon (3d) makes it possible to prevent friction of the cable on the nose of the aircraft.

The traction cable (2g) can be provided with a light signaling system to increase the operational safety of the flight in pairs.

At the end of the traction cable, but before the hook, can be arranged a damping system (2h) dimensioned to reduce

BE2017 / 5540 loading shocks or vibrations during the scooping phase or any other critical phase of operation.

The cable release device (3e) is integrated in the hydrone.

C. Hydrone The hydrone (3) is designed exclusively as a flying tank capable of scooping at higher speeds than existing seaplanes, and in difficult marine conditions. Unlike existing water bomber seaplanes, the hydrone is not based on a multi-role seaplane design with conventional fuselage. No part of the fuselage is provided as a passenger or pilot cabin.

The fuselage of the hydrone is composed horizontally of three parts (3a), (3b), (3c).

(Starting from the bottom) Firstly the slice (3c) making it possible to split the body of water and to draw water thanks to the scoop (3f) at a safety height relative to the main fuselage body, without disturbing the attitude of the aircraft.

Secondly the float (3b) making it possible to split the top of the waves of a rough sea with the minimum possible friction thanks to its hydrodynamic slenderness, comparable to the hulls of floats of racing trimaran sailboats. This float can be equipped with foils or bequets allowing to ensure a

BE2017 / 5540 hydrodynamic lift when loading

1'écopage.

Thirdly the main body of the fuselage (3a) in which the conventional equipment is arranged (tank (3h), landing gear, controls, ...) and whose streamlined shape also makes it possible to split the residues of the heads of waves or to land exceptionally in the event of a breach of the flight protocol.

The slice part of the fuselage is profiled to scoop the water in the most laminar way possible, thanks to a drawing loop which will cross the three horizontal parts of the fuselage in order to convey the water to the tanks.

The scooping holes, forming the scooping head (3f) or scoop, are arranged vertically at the bottom of the slice (3c). The loading is therefore a function of the gradual penetration into the water body (Fig 13), which makes it possible to minimize the shock effect generated by this loading.

The scooping orifices can be arranged in pairs, staggered vertically (3f).

Each scooping orifice (3f) can correspond to a single pipe (3k, 3d) supplying a single tank (3h).

BE2017 / 5540 The pipes form the drawing loop: after the substantially horizontal scooping head follows a 'separation' zone which initiates the curve and the acceleration of the load (3d). At the end of the slice part of the fuselage, the float part of the fuselage allows the enlargement of the section of the pipes and therefore the reduction of the local speed of the water. The loop ends in the conventional part of the fuselage, the pipes (3k) are distributed horizontally in order to be able to reach each of the tanks (3h) in their upper part.

The pipes can be fitted with non-return valves.

The tanks (3h) are contiguous and generally independent.

The tanks (3h) are nevertheless connected to each other by safety valves arranged in the lower part. This device must intervene in the event of accidental or abnormal differential unloading of one or more tanks. It allows the overall load of on-board liquid to be distributed uniformly over all of the tanks in order to ensure the aerial stability of the towed aircraft.

A directional fin may be installed at the base of the slice (3c) in order to gradually adapt the lace of the hydrone to the orientation of the slice in the water, in the same way as an airplane which lands by lateral wind aligns with the movement relative to the ground as soon as it touches it.

BE2017 / 5540 A small rudder can be installed at the rear of the slice (3c) in order to obtain a certain freedom of marine movement in yaw during scooping (Fig 13).

The tanks (3h) comprising the charge of liquid to be dropped are advantageously concentrated as close as possible to the center of gravity in order to optimize the workability and safety of the hydrone (3).

The overflows (31) of the tanks (3h) may be arranged directly above them and discharge the water over the fuselage.

Avionics The avionics of the hydrone will include, in addition to conventional equipment, a dashboard managing the traction system (braking and motorization of the coil) and communicating to pilots flight measurements in pairs (Fig 16). The main measurements of the tractor / cable / hydrone assembly are:

- horizontal angle of incidence of the upstream end traction cable (11) (22)

- horizontal angle of incidence of the downstream end traction cable (14)

- vertical angle of incidence of the traction cable (upstream at least) (10) (13)

-difference in altitude between aircraft (12)

- speed difference between aircraft (15)

-difference in heading or yaw between aircraft (16)

BE2017 / 5540

-difference in pitch between aircraft

-difference in roll between aircraft

- estimated traction force (brake and winding motorization) (19)

- unwinding of the traction cable (18) (21)

- unwinding / winding speed of the traction cable (20)

- hydrone energy reserve (17)

- tank filling status

Analysis of the state of the scooping plan A device (3g) for vertical distance measurements between the hydrone (3) and the body of water makes it possible to know the state of the latter as well as the altitude very precise of the device. This device can be coupled to the altimeter and the conventional gyroscope.

Laser rangefinders (3g), suspended without shock to the vertical (gravity) take the vertical measurement of altitude continuously, at the cardinal points of the plane (forward / aft / port / starboard) as well as in sound center (below the center of gravity) The analysis of these measurements makes it possible to deduce the state of the water body (wave trough, wave frequency, swell trough, swell wave, direction of swell, ...) and indicate the most appropriate slice height.

Other equipment

BE2017 / 5540 The hydrone can be provided with a current generator independent of the tractor, of the APU (auxiliary power unit) or other type (batteries, etc.).

So that the hydrone can move in a 'taxi', in particular after stopping on the landing strip in order to clear it, a small engine of the front or rear landing gear could be provided.

This function can be controlled from the ground.

Operational procedures and flight plan The pair of aircraft (1 and 3) relating to the present invention is under the command of the crew of the tractor aircraft (1)

The hydrone (3) is piloted by a dedicated crew which performs all operational maneuvers with precision, the flight of which is coordinated by the two crews. The hydrone crew communicates all necessary information to the tractor crew and vice versa. The commander of the pair has final authority to unhook the towed aircraft in the event of any problem or emergency that jeopardizes the towing aircraft and the crews on board.

A. arming the system:

The traction structure is introduced into the hold thanks to rollers in the front part (2i) and a mobile booster frame in the rear part (2j). After precise positioning, the structure is fixed to conventional cargo anchors by suitable systems ((1) + (2)). The traction cable is fixed to the hydrone ((2) + (2g) + (3)). The tractor cockpit (3)

BE2017 / 5540 is coordinated at the hydrone (2c) cockpit by duplicating the cockpit equipment.

B. take-off:

Takeoff takes place at a reduced angle of incidence of the tractor, because of the tailgate in a horizontal position.

C. cruise flight:

An empirical optimum of relative position between the two devices (1 and 3) will be chosen in order to benefit from the best efficiency and avoid turbulence.

D. scooping:

In the scooping phase (Fig 16) a more marked angle of incidence will be adopted, as well as a cable unwinding, making it possible to move the tractor (1) to a safety altitude (MDA type, Minimum Descent Altitude) . An empirical optimum of relative position between the two devices as well as a good ratio between the 'drag' and the 'lift' will be chosen in order to secure the tractor as much as possible and to optimize the stability of the hydrone and therefore the efficiency of the process.

Aligned flight:

Aligned flight is the default flight for the tractor airplane (1) and glider (3) pair. In the present invention, the fixed cable length (2) known in aeronautics for gliders gives way to a nominal length serving as a guide. As knowledge of paired flight is limited, cruise aligned flight will be the only one that can be achieved by automatic pilot.

BE2017 / 5540 F. Definition of block flight:

When the two aircraft, tractor (1) and hydrone (3), maintain their relative position, we will speak of block flight. In this case, the horizontal and vertical angles of incidence of the traction cable will be constant and the unwinding or winding of the traction cable will be zero. Block flying is the norm in the conventional tractor / glider pair.

G. Definition of differential flight:

This is the flight phase during which the horizontal angle of incidence and / or the vertical angle of incidence and / or the unwinding of the traction cable (2) vary. In the case of differential flight, the relative position of the two aircraft varies.

H. approach for bombardment:

In order to obtain a precise and effective bombardment, an approach by a differential flight of the two aircraft (1 and 3) can be envisaged, for example to properly marry the site to be bombarded or to decrease the speed of the hydrone and concentrate the dropping .

I. maneuver with unwinding:

The hydrone can be slowed down and / or lower appreciably in altitude with respect to the tractor during a maneuver to move the two aircraft away (1 and 3) and therefore to unwind the traction cable (2).

A deceleration by unwinding, and at constant heading for the two aircraft, will be limited in time and in speed value by the available length of the cable. The total sequence will be the addition of the deceleration phase, the possible speed step

BE2017 / 5540 fixed differential, and the acceleration phase to catch up with the tractor speed.

J. cornice flight:

The hydrone (3) can also be slowed down relative to the tractor (1) during a cornice flight (Fig 15) of the two aircraft, without cable unwinding (2g). The cornice flight is characterized by a conical trajectory of the two aircraft. The tractor follows a wider circle (of radius Rt) than that followed by the hydrone (of radius Rh), at an altitude equal to or greater, in a cone shape. The difference in speed ((Vt) - (Vh or Vhb)) is kept stable between the two aircraft as long as this circular flight is maintained, in the form of a block flight.

The hydrone undergoes a progressive loss of speed during the passage from the linear trajectory to the conical trajectory. Conversely, it is accelerated during the recovery of the linear trajectory.

K. combined flight maneuver:

The course and the cornice flight can be combined to allow high bombardment precision, at low speed (Vhb). Before dropping, the unwinding maneuvers make it possible to reach the target without additional traction effort. After complete release, the release of the hydrone (3) takes place at zero payload. This makes the release maneuver easier and more secure, for a traction force kept constant.

L. landing:

BE2017 / 5540

The tractor (1) presents the hydrone (3) for landing according to the same procedures as a conventional aircraft. The tractor remains at 'MDA altitude'. When the hydrone has landed and a 'go around' is no longer envisaged, the traction cable (2) will be unhooked at its attachment to the right of the hydrone and as quickly as possible rewound. The tractor landing takes place in a second phase, like a normal landing.

The invention is summarized in the various characteristics and embodiments which follow, taken in isolation or in any combination. :

1. The invention discloses a bomber system of liquid, for example water, comprising a removable module to be carried in the hold in a towing cargo plane, a coiled traction cable, permanently towing a non-propelled aircraft called hydrone, provided a scooping device and a liquid bombardment device.

2. The pair of aircraft is under the command of

The crew of the tractor aircraft and the towed aircraft is piloted by a dedicated crew, from the tractor aircraft, which performs all the operational maneuvers with precision, the flight of which is coordinated by the two crews. The commander of the pair has the final authority to win

The towed aircraft putting the towing aircraft and the crews on board in the event of any problem or emergency.

BE2017 / 5540

3. The on-board module consists of a lattice structure capable of transferring the traction loads towards the center of the tractor hold.

4. This on-board module supports the winding assembly comprising the tractor cable reel, the unwinding braking system, the rewinding motorization, the cable condition measurement equipment, the emergency device, as well as the trunking assembly guiding the cable passage through the module.

5. The cable leaves the structure at the rear end, under the cockpit, and passes through a winding stop device, when the cable is fully brought back into the tractor, as well as a stand capable of supporting the damping assembly, more rigid linearly, and hooking at its end.

6. The module supports at the end back on position of piloting 1 'aircraft towed. 7. A wall suitable to the section tractor confined the hold of which the tailgate is maintained open.

8. The attachment device of the towed aircraft is fixed on a pylon allowing the traction force to be aligned as best as possible with the aircraft center of gravity and the scooping pipe curve, for the nominal angle of traction used in the scooping phase.

A system for absorbing tensile shocks or vibrations in the cable is placed at the end of the cable, before the fixing hook.

BE2017 / 5540

An aircraft fuselage system is proposed that is made up of three parts horizontally.

(Starting from the bottom) Firstly the slice allowing to split the body of water and to draw water at a safe height in relation to the main body of the fuselage, while maintaining the attitude of the aircraft.

Secondly, the slender float is capable of resisting penetration through the waves of the water at scooping speed and, exceptionally, ensuring a distress landing in the event of a break in traction.

Thirdly, the main body of the fuselage, also faired, comprises the load as well as the equipment of the aircraft.

11. The slice part of the fuselage is profiled to scoop the water in the most laminar way possible, thanks to a drawing loop which will cross the three horizontal parts of the fuselage and lead to the tanks.

12. The scooping head is formed by all of the scooping orifices, arranged vertically at the bottom of the slice.

13. For points [10] and [11] the drawing loop consists of rigid pipes with variable section and adequate curvature. In the slice part of the fuselage, the narrowness of the pipes is preferred. In the float part of the fuselage allows the widening of the section of the pipes is done gradually in order to obtain a significant reduction

BE2017 / 5540 of the local speed of the water. In the conventional part of the fuselage, the pipes are distributed horizontally and reach the assigned tanks in their upper part.

14. There is also proposed a system of tanks connected together by safety valves arranged in the lower part. This device must make it possible to distribute the overall load of liquid on board uniformly over all the tanks in order to ensure the aircraft's aerial stability.

15. A system is proposed according to point [10] in which a directional fin is installed at the base of the slice in order to gradually adapt the yaw of the aircraft to the orientation of the slice in the water, in the same way that a landing plane aligns with the movement relative to the ground. The tanks are arranged as high as possible in the fuselage, with the overflows crossing the ceiling of the fuselage.

16. A system is disclosed in which the avionics of the towed aircraft comprises a dashboard managing the traction system (braking and motorization of the coil) and communicating the flight measurements in pairs. The main measurements of the tractor, cable and towed aircraft assembly are:

- horizontal angle of incidence of the upstream end traction cable

- horizontal angle of incidence of the downstream end traction cable

- vertical angle of incidence of the traction cable - altitude difference between aircraft

BE2017 / 5540

- speed difference between aircraft

-difference in heading or yaw between aircraft -difference in pitch between aircraft

-difference in roll between aircraft

- estimated traction force (brake and winding motorization)

- unwinding of the traction cable

- unwinding / winding speed of the traction cable

- energy reserve for towed aircraft - tank filling status

17. There is also disclosed a system of instant metric measurements giving the precise altitude of the towed aircraft relative to the level 0.00 of the water body as well as the dynamic state of agitation of the water body. This system is coupled to the conventional altimeter and gyroscope.

This system is composed of laser rangefinders, suspended without shock to the vertical gravity) which take the vertical measurement of altitude continuously, at the cardinal points of the aircraft (forward / aft / port / starboard) as well as in its center ( directly above the center of gravity)

This system analyzes these measurements and deduces the condition of the water level and finally indicates the most appropriate slice height.

18. The traction structure is introduced into the hold thanks to rollers in the front part and a mobile booster frame in the rear part. After precise positioning, the structure is fixed to conventional cargo anchors by suitable systems

BE2017 / 5540

19. Flight procedure adapted for the invention characterizing the scooping phase in which an angle of incidence more marked than the cruise flight will be adopted between the two aircraft, as well as a cable unwinding, making it possible to remove the tractor at a safe altitude (MDA, Minimum Descent Altitude) following an empirical optimum of relative position between the two devices.

20. This flight procedure is characterized by a controlled unwinding in flight of the traction cable in which the towed aircraft slows down and / or decreases appreciably in altitude with respect to the tractor during a maneuver for the mutual separation of the two aircraft. The total length of the cable unwinding of this procedure is the addition of the deceleration phase of the towed aircraft, any level of fixed differential speed between the two aircraft, and the acceleration phase of the towed aircraft for catch up with tractor speed.

21. We therefore disclose a pair flight procedure consisting of a towing aircraft and a towed aircraft characterized by the slowing down of the towed aircraft relative to the towing aircraft during a ledge flight. This flight is characterized by a conical trajectory of the pair in which the tractor follows and maintains a wider circle than the circle followed by the towed, at an altitude equal to or higher, in the shape of a cone pointing downwards. The difference in speed is kept stable between the two aircraft

BE2017 / 5540 as long as this generally circular flight is maintained, in the form of a block flight.

The tractor undergoes a progressive loss of speed during the transition from the linear trajectory to the trajectory

conical. Conversely he is accelerated then of the recovery of the trajectory linear, in end of procedure. 22. This procedure of theft can so be characterized by a combination of unfolded and the flight in cornice.

24. A landing procedure adapted to the aforementioned invention is also proposed, characterized by a conventional landing procedure for the towed aircraft while the tractor remains at the lowest altitude MDA and always maintains the traction tension necessary for the flight. of the pair. When the towed aircraft has landed and / or a 'go around' is no longer envisaged, the traction cable will be unhooked at its attachment to the right of the towed aircraft and as quickly as possible rewound. The tractor landing becomes independent of the towed vehicle.

Claims (11)

claims 1. Liquid bomber system comprising a cargo aircraft (1), a removable module ( 2) to be carried in the hold in said cargo aircraft, the module comprising a windable traction cable (2g), capable of permanently towing a second aircraft ( 3) non-powered which is provided with a scooping device (3c, 3f) and with a device for bombarding said liquid. 2. System according to claim 1 in whichone liquid is composed of at least 95 O. O water • 3. System according to claim 1 in which one position of 1 'piloting (2c, 2e) aircraft towed east located in the towing aircraft (1). 4. System according to the preceding claim wherein the cockpit (2c, 2e) is integral with the on-board module (2). 5. System according to claim 1 wherein the on-board module consists of a trellis structure (2a) capable of transferring the traction loads towards the center of the hold of the tractor aircraft. 6. System according to any one of the preceding claims, in which the on-board module (2) supports the winding assembly comprising at least one of the following elements: the cable reel 2017/5540 BE2017 / 5540 tractor (2b), the unwinding braking system, the rewinding motorization, the cable condition measuring equipment (2g), the emergency device, as well as the trunking assembly guiding the passage of cable through the module. 7. System according to any one of the preceding claims, in which the cable leaves the structure (2) at the rear end, under the cockpit (2c, 2e), and passes through a winding stop device. , when the cable is fully returned to the tractor (1), as well as a stand capable of supporting the damping assembly, more linearly rigid, and hooking at its end. 8. System according to any one of the preceding claims in which the module (2) supports or comprises at the rear end the cockpit of the towed aircraft (2). 9. System according to any one of the preceding claims, in which a wall adapted to the section of the tractor (1) confines the hold, the tailgate of which is kept open. 10. System according to any one of the preceding claims, in which the attachment device of the towed aircraft is fixed to a pylon (3d) making it possible to best align the traction force with the center of gravity of the aircraft and to the curve of 2017/5540 BE2017 / 5540 scooping piping, for the nominal traction angle used in the scooping phase. 11. System according to any one of the claims 5 previous in which a device depreciation (2h) shocks from traction or vibration in the cable is planned available 1'extrémité of this one before the hook fixation.