DEVICE FOR PNEUMATIC LAUNCHING OF A DRONE

Description

[0001] The technical field of the invention is that of pneumatic launching devices, and more specifically, that of pneumatic launching devices for drones.

[0002] Drones can carry payloads for civilian or military missions, including surveillance, intelligence gathering, combat, and transport. Smaller in size, less expensive, and simpler to operate than a manned aircraft, drones are experiencing significant growth.

[0003] Several methods of launching drones are known, including pneumatic launching devices.

[0004] A pneumatic launch device is a device that uses compressed air, or any other type of pressurized gas, to cause the drone to launch.

[0005] Typically, a pneumatic launch device consists of a pressurization chamber that is pressurized by a compressed gas. The release of the pressure contained in the chamber generates energy, which in turn propels the drone.

[0006] There are many types of pneumatic launching devices. In particular, pressure can be released in various ways.

[0007] One known type of pneumatic launching device is a pneumatic catapult drone launcher, such as the one disclosed, for example, in French patent application FR2297770 A1. The operating principle of this pneumatic catapult is the release of a pressurized gas in a telescopic assembly of two concentric cylindrical tubes so as to cause the rectilinear movement of one relative to the other.

[0008] Another known type of pneumatic launch device is a launch tube device, such as those disclosed in U.S. patent US7584925 B2 and in international patent applications WO2015 / 127178, WO2013 / 011412 and WO2014 / 035518.

[0009] The purpose of these launch tube devices is to propel the drone a few meters above the vehicle carrying the launch tube for the deployment of this drone, in order to avoid any contact of the drone with the antennas mounted on the vehicle and to deploy the drone quickly.

[0010] In the launch device according to US patent 7584925 B2, at launch a launch gas contained in a launch gas tank is released into a launch tube after the opening of a valve system, a first part of this launch gas forces a free sliding piston mounted inside the launch tube to move towards the open front end of the launch tube, and a second part of the launch gas exits the launch tube through its open front end.

[0011] In the launch device according to patent application WO2015 / 127178, during launch a compressed gas contained in a chamber is released into a launch tube containing the drone after the opening of a discharge valve.

[0012] In the launch device described in patent application WO2014 / 035518, during launch, a gas generated by a gas generator located inside a launch tube is introduced into a high-pressure volume defined between a skirt of a skid and an enclosure containing the gas generator. The skirt is detachably coupled to the enclosure by means of an adhesive coupling. The resulting gas pressure exerts pressure against the skirt until the adhesive coupling ruptures, once a certain rupture pressure is reached in the high-pressure volume. Then, the continued gas generation pushes the released skirt against the wall of the launch tube, propelling the skid along the tube until the drone is ejected from the launch tube.The launch tube devices described above have the disadvantage of not allowing sufficient control of the value of the gas pressure by which the drone is ejected, and therefore not allowing control of the speed and height of the drone ejection, so it is necessary to provide a safety margin before the deployment of the drone in order to prevent it from coming into contact with, for example, the antennas of the vehicle.

[0013] The present invention aims to provide a pneumatic launching device that allows control of the launch pressure by which the drone is ejected, thus capable of reliably and reproducibly ejecting a drone and through which an effectively rapid deployment of the drone can be implemented.

[0014] The solution according to the present invention is based on the use of means allowing the drone to be instantly ejected by the pressure by which it is desired that the drone be ejected, and not a progressive, or even partial, release of gas pressure behind the drone as in prior art devices.

[0015] Patent application WO2013 / 011412 describes a device according to the preamble of claim 1.

[0016] The present invention therefore relates to a pneumatic launching device for a drone, a device comprising: a longitudinal launch tube having a first, rear end, which is closed, and a second, front end, which is open, and whose interior defines a launch chamber intended to receive a drone and in which is located a seat against which the drone is positioned before its launch; a pressurization chamber located at the rear end of the launch tube and capable of being pressurized by a pressure source, the pressurization chamber having a first, front end, in which is provided a passage opening leading into the launch chamber and, in use, behind the drone placed against the seat; and means for temporarily closing the passage opening capable of instantaneously changing from a closed configuration, in which the passage opening is hermetically sealed, to an open configuration in which the passage opening is completely open,

[0017] the temporary sealing means being arranged to switch from the closed configuration to the open configuration instantaneously under the action of the gas pressure inside the pressurization chamber, after the latter has reached a predetermined pressure, called the trigger pressure, and by the fact that the cross-section of the passage opening is large enough that instantaneously, upon the passage of the temporary sealing means from the closed configuration to the open configuration, the gas pressure prevailing in the pressurization chamber and the space behind the drone, then in communication with each other, is the desired launch pressure for the drone,

[0018] characterized by the fact that the device includes said pressure source, which is formed by an internal gas source disposed inside the pressurization chamber, said pressure source includes, placed in the pressurization chamber, a diffuser, delimiting a reservoir of a first reactant, and a second reactant, the first and second reactants, when brought into contact with each other, reacting by generating a pressurization gas for the pressurization chamber, a solenoid valve being disposed so as to selectively allow the fluidic communication of the reservoir and the pressurization chamber.

[0019] The expression "completely open" means that the means of temporary closure are clear of the passage opening.

[0020] Advantageously, the cross-section of the passage opening represents between 30% and 50% of the cross-section of the launch chamber.

[0021] It is possible to design the temporary closing means to transition from a closed to an open configuration by actuating a mechanically operated release mechanism. For example, the temporary closing means could include a freely pivoting flap at the exit of the passage opening, or two freely pivoting flaps about axes located on either side of the passage opening, held in a closed position by a mechanical latch that can be moved between a latch position where the flap is locked in the closed position and a release position where it is disengaged. The flap is then instantly pivoted and opens the passage opening by gas pressure. The latch movement can be controlled by any suitable means, such as an electromagnet. In this way, the drone launch command is executed by controlling the latch.

[0022] According to a preferred embodiment, the temporary closing means are arranged to automatically switch from the closed configuration to the open configuration as soon as the gas pressure inside the pressurization chamber reaches the trigger pressure.

[0023] The means of temporary closure may then advantageously include a rupture disc assembly which is disposed at the passage opening and includes a calibrated membrane extending across the passage opening so as to close it, the membrane being sized to rupture at the trigger pressure.

[0024] The calibration membrane can, for example, be made of stainless steel, plastic, or graphite. Of course, it can be made of any other suitable material.

[0025] The calibrated diaphragm can be designed to break all around its periphery, at which point it is made integral with the pressurization chamber, or to break from its center, or according to any other mode of rupture allowing the passage opening to be completely opened.

[0026] The rupture disc assembly can be removably attached to the pressurization chamber. Preferably, the rupture disc assembly comprises a support ring and a fixing ring of the same dimensions, fixed to each other by fixing elements passing through holes provided for this purpose in the rings, with the periphery of the calibrated diaphragm sandwiched between the rings, the rupture disc assembly being removably fixed to the front end of the pressurization chamber also by said fixing elements.

[0027] Such a rupture disc assembly offers the advantage of both low cost and rapid opening. During maintenance and refurbishment of a new drone, it is simply a matter of replacing the ruptured membrane with a new one, which is more economical than replacing, for example, a pyrotechnic initiator and a gas-generating charge.

[0028] The rear end of the launch tube can be formed by a base removably attached to an internal shoulder of the launch tube. From this base extends a tubular section whose longitudinal axis is coaxial with the longitudinal axis of the launch tube and which, together with the base, defines the pressurization chamber. A sealing gasket is interposed between the tubular section and the inner annular edge of the inner shoulder. The device is then simple in structure to manufacture and assemble.

[0029] The front end of the launch tube can be closed with a watertight cap.

[0030] Preferably the first reactant is hydrogen peroxide (H2O2) under pressure and the second reactant is a solid catalyst based on potassium permanganate (KmnO4).

[0031] The device according to the present invention may further include a launch shoe adapted to be received in the launch chamber and brought into contact with the seat, the launch shoe being configured to contain and surround the drone before launch and during its movement along the launch tube during ejection. The shoe provides protection and guidance for the drone within the launch tube during the launch phase, and it also guides, pressurizes, and distributes the energy developed by the gas pressure.

[0032] It is therefore appropriate to specify here that according to the present invention the drone can be in direct contact against the seat of the launch tube, or in indirect contact with it, via the shoe.

[0033] Advantageously, the launching shoe is formed of several separable segments, preferably four segments.

[0034] To better illustrate the object of the present invention, a particular embodiment thereof will be described below, with reference to the accompanying drawings. These drawings show: [ Fig.1 ] is a side view, in longitudinal section, of the pneumatic launching device according to a particular embodiment not forming part of the claimed invention, with a pressure source according to a first embodiment; [ Fig.2 ] is a side view, following a first partial longitudinal section plane, of the pneumatic launching device of the [ Fig.1 ], with a pressure source according to the present invention; [ Fig.3 ] is a longitudinal cross-sectional view of the pressure source according to the present invention, along a cutting plane perpendicular to said first cutting plane; [ Fig.4 ] is an exploded perspective view of the device of the [ Fig.1 ], omitting the sabot and the drone; [ Fig.5 ] is an exploded perspective view of the skid and drone, in their pre-launch configuration; and [ Fig.6 ] is a perspective view of the boot and the drone, in their configuration after launch.

[0035] If we refer first to Figures 1 , 5 And 6 , we can see that the pneumatic launching device 1 according to the present invention is intended for launching a drone-type object 2.

[0036] Such a drone 2 typically comprises a basic body 20 containing a powertrain, a battery pack, and navigation electronics. The drone 2 shown in the Figures 5 And 6 includes two counter-rotating rotors 21a, 21b, namely two superimposed propellers. It should be noted that the drone 2 could include any number of rotors. The blades 22 of each rotor 21a, 21b are foldable and can therefore be moved from a folded position ([ Fig.5 ]) to a deployed position ( [ Fig.6 The drone 2 is equipped with a payload 23 removably mounted on the base body 20. This payload 23 can be lethal or non-lethal. For example, the drone 2 could be equipped with a lethal explosive charge, a non-lethal charge capable of releasing paint or smoke, or an optronic payload for observation and detection.

[0037] If we now refer to Figures 1 à 4 , we can see that the device 1 includes a launch tube 3 with longitudinal axis A1, intended to receive the object to be launched, namely the drone 2, before its launch, and ejection means 4 to eject the drone 2.

[0038] The launch tube 3 has a general cylindrical shape around its longitudinal axis A1, and it has a front end 3a forming the mouth for the exit of the drone 2 and a rear end 3b in the region of which the ejection means 4 are arranged.

[0039] It is emphasized here that the terms "front" and "back" are understood by reference to the predetermined direction of movement of the drone 2 relative to the launch tube 3 during launch.

[0040] The front end 3a is closed, before launch, by a circular sealing plug 30 whose diameter corresponds to the outside diameter of the launch tube 3. An O-ring 31 is interposed between the plug 30 and the inner wall of the launch tube 3, at the front end 3a.

[0041] The rear end 3b is formed by a base 32 which is in the form of a block of circular section, the diameter of which corresponds to the external diameter of the launch tube 3. The base 32 is fixed to an internal shoulder 33 of the launch tube 3, of annular shape, by fixing members 34, such as screws, passing through holes provided in the base 32 and holes provided in the internal shoulder 33 and situated opposite each other.

[0042] The launch tube 3 defines within it a cylindrical launch chamber 35 having, in the region of the rear end 3b, a seat 36, here formed by the inner shoulder 33, against which the drone 2 will be placed before ejection out of the launch tube 3 by the ejection means 4.

[0043] The ejection means 4 include a pressure source 5 or 5', a pressurization chamber 6 and temporary closure means 7.

[0044] The pressure source 5 or 5' is intended to allow the pressurization of the pressurization chamber 6 by compressed gas, which may be air, an inert gas, steam, etc., or any combination thereof.

[0045] It should therefore be emphasized that, although the term "pneumatic" is used to designate the launching device according to the present invention, it is not limited to the use of air as the launching gas for drone 2.

[0046] The pressure source can be any source of gas pressure.

[0047] In the embodiment illustrated on the [ Fig.1 ] and not being part of the claimed invention, for reasons of space, the pressure source 5 is an external pressure source, that is to say that it is disposed outside the launch tube 3 and is able to be put in communication with the pressurization chamber 6 by means of a pneumatic fitting 50. This pneumatic fitting 50 has an inlet orifice which opens into the base 32.

[0048] The pressurization chamber 6 is laterally delimited by a tubular part 60, with longitudinal axis A2, extending perpendicularly from the transverse wall of the base 32, in other words parallel to said longitudinal axis A1, in the direction of the front end 3a of the launch tube 3. Thus, the pressurization chamber 6 has a rear end 6b closed by said transverse wall and an open front end 6a, and is located inside the rear region of the launch tube 3. The tubular part 60 is here formed as a single unit with the base 32, but alternatively the pressurization chamber 6 can be fixed to it by any suitable means.

[0049] A gas inlet orifice 61 is provided in a region of the side wall of the pressurization chamber 6 which is located in the base 32, to allow gas entering through an inlet orifice of the base 32 to enter the pressurization chamber 6.

[0050] In the implementation of Figures 2 And 3 , the pressure source is an internal pressure source 5', that is to say disposed inside the launch tube 3, and more particularly, inside the pressurization chamber 6 which is here formed by a pressurization bell 60'.

[0051] The pressure source 5' is a chemical initiator, here based on the reaction between hydrogen peroxide (H2O2) and potassium permanganate (KMnO4).

[0052] The chemical initiator 5' includes a diffuser 51 delimiting a reservoir 52 of H 2 O 2, a solenoid valve 53, a solid catalyst 54 based on KMnO 4, a piston 55, a spring 56 and a reservoir cap 57.

[0053] The pressurization bell 60' is in the form of a tubular body intended to receive all the components of the chemical initiator 5' and fixed to the base 32 so as to delimit a chamber similar to that formed by the tubular part 60, namely located at the rear end 3b of the launch tube 3. The longitudinal axis of the bell 60' is thus also coaxial with the longitudinal axis A1 of the launch tube 3.

[0054] The diffuser 51 is formed by a generally cylindrical part, one end of which has an annular flange 51a on which the bell 60' is mounted, with a sealing gasket interposed between the two, and which is secured to the base 32, notably by screws, again with a sealing gasket interposed between the two. The generally cylindrical part comprises, starting from the flange 51a, a rear portion 51b in which a cavity is formed opening into the central opening of the flange 51a and receiving the solenoid valve 53, a tubular front portion 51c whose front end is closed by the reservoir cap 57, and an intermediate portion 51d separating the rear and front portions 51b, 51c.

[0055] The piston 55 is mounted inside the front part 51c, between the plug 57 and the intermediate part 51d. The spring 56 is a helical spring mounted between the piston 55 and the plug 57, the ends of the spring 56 bearing respectively against the piston 55 and the plug 57. The plug 57 and the piston 55 each have a cavity, said cavities being able to receive the spring 56 when the plug 57 and the piston 55 are in contact with each other. The region delimited laterally by the inner side wall of the front part 51c, at the rear by the intermediate part 51d and at the front by the piston 55 constitutes the H2O2 reservoir 52 which can be pressurized by the action of the piston 55 and the spring 56. The front end of the plug 57 is made integral with the front end of the bell 60', the latter being itself made integral, in particular by screwing, with the temporary closing means 7.

[0056] The KMnO4-based solid catalyst 54 is received in the space formed between the first part 51b of the diffuser 51 and the inner side wall of the bell 60'. This solid catalyst 54 is therefore in the form of an annular body having a rear wall in contact with the flange 51a.

[0057] As can be seen more clearly on the [ Fig.2 ], the first channels 51e are provided in the intermediate part 51d so as to establish fluidic communication between the reservoir 52 and a free space 51f in the cavity in which the solenoid valve 53 is housed. The first channels 51e are here parallel to the longitudinal axis of the diffuser 51. If we now refer to the [ Fig.3 [ ], we can see that second oblique channels 51g are also provided in the intermediate part 51d so as to put the pressurization chamber 6 into fluidic communication with an outlet passage 51h provided in the center of the intermediate part 51d and which can be put into fluidic communication with said free space 51f by actuation of the solenoid valve 53. It is therefore possible to control the solenoid valve 53 so as to bring the contents of the reservoir 52 into the pressurization chamber 6 where the solid catalyst 54 is located.

[0058] The exothermic chemical reaction between the solid catalyst 54 based on KMnO4 and the H2O2 contained in the reservoir 52 allows a very large quantity of oxygen and water vapor to be generated, allowing the pressurization chamber 6 to be pressurized up to the trigger pressure.

[0059] The longitudinal axis A2 of the pressurization chamber 6 is coaxial with the longitudinal axis A1 of the launch chamber 35. The outer diameter of the pressurization chamber 6 is less than the inner diameter of the launch tube 3, so that a free space is formed between the outer wall of the pressurization chamber 6 and the inner wall of the launch tube 3, allowing to receive there if necessary part of the object to be ejected.

[0060] The pressurization chamber 6, whether defined by the tubular part 60 or the pressurization bell 60', has, at its open front end 6a, an internal annular rim 62 which delimits a circular passage opening 63 leading into the launching chamber 35.

[0061] The temporary closing means 7 are arranged at the passage opening 63 and serve to selectively close it. More specifically, the temporary closing means 7 are capable of closing the passage opening 63 before launch and leaving it open at the moment of launch.

[0062] In other words, the temporary sealing means 7 are capable of instantaneously switching from a closed to an open configuration. In the closed configuration, the forward end 6a is closed, so that the pressurization chamber 6 is hermetically sealed and no gas exchange is possible between the pressurization chamber 6 and the launch chamber 35, which are not connected. In the open configuration, the passage opening 63 is not sealed, the forward end 6a is open, the pressurization chamber 6 and the launch chamber 35 are connected, and the gas contained in the pressurization chamber 6 enters the launch chamber 35 to eject the drone 2.

[0063] In preferred embodiments of the present invention ( Figures 1 à 4 ), the temporary closure means 7 include a rupture disc assembly 70 comprising a calibrated membrane 71.

[0064] The rupture disc 70 includes a support ring 72 fixed to the front end 6a of the pressurization chamber 6 and carrying the calibrated diaphragm 71.

[0065] The support ring 72 has a first side, a second side, an outer peripheral edge, and an annular inner peripheral edge, the latter defining a central opening 72a whose diameter, i.e., the inner diameter of the support ring 72, is equal to the diameter of the passage opening 63. The outer diameter of the support ring 72 is equal to the outer diameter of the tubular section 60, or, where applicable, to the outer diameter of the bell 60'. The first side of the support ring 72 is applied against the inner rim 62, and the second side of the support ring 72 is therefore oriented towards the forward end 3a of the launch tube 3. In other words, the support ring 72 is interposed between the forward end 6a of the pressurization chamber 6 and the launch chamber 35.

[0066] The calibrated membrane 71 extends across the central opening 72a of the support ring 72. Thus, in the closed configuration, the calibrated membrane 71 completely closes the passage opening 63.

[0067] Regarding the mode of rupture of the membrane 71, different variants may be suitable, provided that the rupture of the membrane 71 exposes the entire cross-section of the passage opening 63. For example, the membrane 71 could rupture at its periphery, namely its junction area with the support ring 72, or at its center.

[0068] The rupture disc assembly 70 is fixed to the pressurization chamber 6 by a retaining ring 73. The retaining ring 73 is a part similar to the support ring 72 and is in the form of a flat annular section with the same dimensions as the support ring 72. One side of the retaining ring 73 is pressed against the other side of the support ring 72. Holes, suitable for receiving fasteners 74, are provided in the retaining ring 73, so as to align with corresponding holes provided in the support ring 72 and in the inner rim 62. Thus, the rupture disc assembly 70 is fixed to the open end 6a of the pressurization chamber 6 by fasteners 74 passing through the retaining ring 73, the diaphragm 71, the support ring 72, and the inner rim 62, and whose heads are located on the side of the launching chamber 35.In the assembled state of the rupture disc assembly 70, it is therefore interposed between the inner rim 62 and the fixing ring 73. Such an assembly is easy and allows the rupture disc assembly 70 and the membrane 71 to be easily and quickly disassembled after rupture, in order to replace it with another rupture disc carrying an unbroken membrane, or to replace only the membrane.

[0069] If we refer again to Figures 1, 2 , 5 And 6 , we can see that device 1 also includes a launching shoe 8 intended to receive drone 2.

[0070] The launch pad 8 is sized and configured to fit into the launch chamber 35 to guide the drone 2 through the launch tube 3 during the launch phase, and to surround the drone 2 to protect it during launch. It should be noted that a different pad 8 is defined depending on the profile of the drone 2 and its payload 23.

[0071] In the particular embodiment shown, the shoe 8 is formed of several separable segments 80, in particular four segments 80. These segments 80 delimit between themselves a drone reception space 81 having an opening intended to be located opposite the front end 3a of the launch tube 3. These segments 80 also delimit between themselves a reception space 82 for the pressurization chamber 6, having an opening intended to allow the passage of the pressurization chamber 6 when the shoe 8 is introduced into the launch chamber 35.

[0072] The 80 segments can be identical.

[0073] Alternatively, the skid 8 could be formed of four separable segments, three identical segments and one segment containing a charging and communication device 9 between the drone 2 and the launch tube 3. Since the skid 8 is intended to be ejected from the launch tube 3 and to detach from the drone 2 after launch, the charging and communication device 9 is wireless. Preferably, this device 9 is inductive and includes a transmitting coil adapted to cooperate with a receiving coil housed in the drone 2. This device 9 further includes spring contacts 90 adapted to cooperate with a contact plate provided in the launch tube 3 for the connection between this device 9 and the launch tube 3.

[0074] Device 1 enables the launch of drones by controlling the launch pressure by which drone 2 is ejected, and therefore a reliable and reproducible ejection for rapid deployment of drone 2.

[0075] This is possible because: on the one hand, the membrane 71 is calibrated to open by rupturing when the pressure applied to it by the gas present in the pressurization chamber 6 reaches a predetermined value, which will be the so-called trigger pressure, the rupture disc assembly 70 then passing instantaneously into its open configuration, and on the other hand, the cross-section of the passage opening 63 is large enough so that immediately after the rupture of the membrane 71, the pressure which reigns in the volume composed of the pressurization chamber 6 and the free space of the launch chamber 35 located between the pressurization chamber 6 and the drone 2 (namely here the receiving space 82 formed by the shoe 8), is the desired launch pressure for the drone 2.

[0076] Indeed, at the very moment of rupture of the calibrated membrane 71, the compressed gas will instantly occupy all the free volume at its disposal.

[0077] Therefore, depending on the characteristics of the launch tube, such as its inner diameter and length, and of the drone, such as its weight, speed and height at which it must be ejected before it can be safely deployed, the launch pressure can be defined in advance, namely the gas pressure that should be applied to it when it is in position against the seat 36 taking into account the volume of the pressurization chamber 6 and the volume of said free space, and thus the trigger pressure, namely the gas pressure in the pressurization chamber 6 which will make it possible to obtain the launch pressure after rupture of the calibrated diaphragm 71.

[0078] Thus, when we want to launch a drone 2, we first introduce the launch shoe 8, into the receiving space 81 of which the drone 2 is received, through the open front end 3a of the launch tube 3, until it comes into contact with the seat 36, then we close the front end 3a of the launch tube 3 with the sealing cap 30.

[0079] When launching drone 2, the pressure source 5 or 5' is connected to the pressurization chamber 6 or activated to pressurize the pressurization chamber 6 to the desired trigger pressure. As soon as the trigger pressure is reached, the diaphragm 71 ruptures, opening the passage 63. The compressed gas previously contained in the pressurization chamber 6 is released and instantly occupies the receiving space 82 of the skid 8, applying a thrust force against its face and ejecting the skid 8 and the drone 2 from the launch tube 3, simultaneously ejecting the airtight plug 30. Once ejected from the launch tube 3, the skid 8 separates into segments 80 due to air friction and the thrust exerted by the drone 2's blades 22 as they move into the deployed position.Once at its peak, drone 2 starts up, stabilizes, and its mission can begin.

[0080] If launching a plurality of drones 2 is desired, a plurality of launching devices 1 according to the present invention can be mounted on the same vehicle (not shown). In this case, and if the pressure source is external, only one pneumatic circuit is required to pressurize the pressurization chambers 6. In this embodiment, each launching tube 3 can be color-coded according to the payload 23 with which the drone 2 is equipped. This allows for rapid visual identification of the object to be ejected.

[0081] It is understood that the particular embodiments which have just been described have been given by way of example and not limitation, and that modifications may be made without departing from the scope of the present invention, as limited by the claims.

Claims

1. - A device (1) for pneumatic launching of a drone (2), the device (1) comprising: - a longitudinal launch tube (3) having a first, rear end (3b), which is closed, and a second, front end (3a), which is open, and the interior of which defines a launch chamber (35) intended to receive a drone (2) and in which there is a seat (36) against which the drone (2) is positioned before its launch; - a pressurization chamber (6) located at the rear end (3b) of the launch tube (3) and capable of being pressurized by a pressure source (5'), the pressurization chamber (6) having a first, front end (6a) in which is provided a passage opening (63) leading into the launch chamber (35) and, in use, behind the drone (2) placed against the seat (36); and - means (7) for temporarily closing the passage opening (63), capable of switching instantaneously from a closed configuration, in which the passage opening (63) is closed in a sealed manner, to an open configuration in which the passage opening (63) is fully open, the temporary closing means (7) being arranged to switch from the closed configuration to the open configuration instantaneously under the action of the gas pressure inside the pressurization chamber (6), after the latter has reached a predetermined pressure, referred to as the trigger pressure, and the cross section of the passage opening (63) being sufficiently large that, instantaneously with the switching of the temporary closing means (7) from the closed configuration to the open configuration, the gas pressure prevailing in the pressurization chamber (6) and the space located behind the drone (2), then in communication with each other, is the desired launching pressure for the drone (2), characterized in that it comprises said pressure source (5'), which is formed by an internal gas source arranged inside the pressurization chamber (6), said pressure source (5') comprising, placed in the pressurization chamber (6), a diffuser (51), delimiting a reservoir (52) with a first reactant, and a second reactant (54), the first and second reactants, when brought into contact with each other, reacting to generate a gas for pressurizing the pressurization chamber (6), a solenoid valve (53) being arranged so as to allow selectively a fluid communication between the reservoir (52) and the pressurization chamber (6).

2. - The device (1) according to claim 1, characterized in that the cross section of the passage opening (63) is between 30% and 50% of the cross section of the launch chamber (35).

3. - The device (1) according to any one of claims 1 and 2, characterized in that the temporary closing means (7) are arranged to switch from the closed configuration to the open configuration automatically upon the gas pressure inside the pressurization chamber (6) reaching the trigger pressure.

4. - The device (1) according to claim 3, characterized in that the temporary closing means (7) comprises a rupture disc assembly (70) that is disposed at the passage opening (63) and comprises a calibrated diaphragm (71) extending across the passage opening (63) so as to close it, the diaphragm (71) being dimensioned to break at the trigger pressure.

5. - The device (1) according to claim 4, characterized in that the rupture disc assembly (70) is removably fixed to the pressurization chamber (6).

6. - The device (1) according to claim 5, characterized in that the rupture disc assembly (70) comprises a support ring (72) and a fixing ring (73) of the same dimensions and fixed to each other by fixing members (74) passing through holes provided for this purpose in the rings (72, 73), with the periphery of the calibrated diaphragm (71) sandwiched between the rings (72, 73), the rupture disc assembly being removably fixed to the front end (6a) of the pressurization chamber (6) also by said fixing members (74).

7. - The device (1) according to any one of claims 1 to 6, characterized in that the rear end (3b) of the launch tube (3) is formed by a base (32) removably fixed to an inner shoulder (33) of the launch tube (3), from which base (32) extends a tubular part (60, 60'), the longitudinal axis (A2) of which is coaxial with the longitudinal axis (A1) of the launch tube (1) and which defines, together with the base (32), the pressurization chamber (6), a gasket (31) being interposed between the tubular part (60, 60') and the inner annular edge of the inner shoulder (33).

8. - The device (1) according to any one of claims 1 to 7, characterized in that the first reactant is hydrogen peroxide (H2O2) under pressure and the second reactant (54) is a potassium permanganate (KMnO4)-based solid catalyst.

9. - The device (1) according to any one of claims 1 to 8, characterized in that it further comprises a launch sabot (8) capable of being received in the launch chamber (35) and brought into contact against the seat (36), the launch sabot (8) being configured to contain and surround the drone (2) before launch and during its movement along the launch tube (3) during ejection.

10. - The device (1) according to claim 9, characterized in that the launch sabot (8) is formed of several separable segments (80), preferably four segments.