Patent Publication Number: US-2022234755-A1

Title: Assembly comprising a launch motor vehicle and a jet-powered drone aircraft, and method for transporting and releasing a load

Description:
TECHNICAL FIELD OF THE INVENTION 
     The invention relates to the launching of a drone. It also refers to the delivery of a load by air to a drop zone. 
     PRIOR ART 
     Solutions for launching drones from stationary or moving ground vehicles are known. The drones in question are generally of small wingspan and low mass, and propelled by propellers that do not allow for high thrust at takeoff and high speeds in the later phases of flight, as illustrated for example in U.S. Pat. No. 7,665,691 B2 or US 2019/047726 A1. The known means do not allow us to consider the takeoff of drones of greater mass and scale. 
     They also do not optimize the drone and its launcher in a way that minimizes the energy consumption of the drone during takeoff and during the later phases of flight, with the aim of maximizing the range or speed of intervention. 
     DISCLOSURE OF THE INVENTION 
     The invention aims to remedy the disadvantages of the state of the art and to propose means of launching a drone with a large wingspan and/or high mass from the ground, with the aim of carrying out a mission, in particular of reconnaissance or of dropping a load, the load being able to comprise, in particular, rescue equipment, foodstuffs, ammunition, means of transmission, weapons or a machine, rapidly and at a distance from the launch zone. 
     For this purpose, an assembly is proposed comprising a launch vehicle and a drone, the motorized launch vehicle being capable of rolling on a launch track to exceed a given speed threshold with respect to a surrounding air mass, the motorized launch vehicle being provided with a launch ramp cooperating with the drone to, in a launch position, guide the drone in translational motion from a starting position in a direction of launch towards the front of the motorized launch vehicle, the drone comprising one or more jet engines and not comprising a landing gear. 
     The term “engine” is used here to mean a jet engine, in particular a turbojet engine. The propulsion of the drone by one or more engines allows the transport of a large payload, with a high speed of intervention, with a large range. 
     The ability to launch from the moving motor vehicle contributes to the limitation of the energy to be expended by the drone in the takeoff phase, which also contributes to an increase in payload and range. The motor vehicle also allows the assembly to be moved to an optimal area for launching. For a rescue mission at sea, for example, the motor vehicle can be brought to a point on the coast that is favorable, in terms of wind conditions, in order to reach the target drop zone in the shortest possible time. 
     The absence of landing gear, meanwhile, allows for a reduction in the empty weight and volume of the drone and a significant reduction in drag, which also contributes to an increase in payload and range. In addition, the absence of landing gear allows for mechanical simplification which limits the risk of failure. 
     The motor vehicle is preferably an all-terrain vehicle, a military vehicle or a special vehicle, with the ramp being positioned on the roof of the vehicle or on a platform provided for this purpose. An all-terrain vehicle facilitates, if necessary, a launch from an unprepared runway, for example, from a beach in the case of a rescue at sea. 
     Preferably, an active suspension is arranged between a chassis and wheel sets of the motor vehicle, or between the launch ramp and the chassis of the motor vehicle, or between a carriage and a rail of the launch ramp, to stabilize the drone. 
     In one embodiment, the drone has a fuselage and a canopy, the canopy preferably with a span greater than a track width of the launch vehicle. More generally, the drone can have a wingspan of more than 2 meters, and preferably more than 2.5 meters, or even more than 3 meters. If necessary, the drone can have a variable geometry, for example with folding wings, so that the width of the wing for transport is narrower than for launch and flight. 
     According to an embodiment, the assembly further comprises at least one locking mechanism, movable between a locking position for securing the drone relative to the launch ramp in a cocked position, and an unlocking position allowing movement of the drone relative to the launch ramp. In particular, the hooking device could foreseeably be provided with a trigger, preferably mechanical, electromechanical or pyrotechnical, preferably piloted so as not to be triggered as long as a predetermined condition is not fulfilled, the predetermined condition being one of the following conditions, or a combination of several conditions among the following conditions:
         the drone&#39;s engine(s) deliver a thrust above a given threshold;   a force exerted by the drone on the attachment device is lower than a given threshold;   the motor vehicle has reached or exceeded the given speed threshold in relation to the surrounding air mass;   the motor vehicle has reached or exceeded a given speed threshold;   the launch ramp has a given inclination or angular area in   the launch ramp has a given inclination or in a given angular area with respect to the vehicle&#39;s attitude.   one or more heat shields or deflectors are in a functional position;   a retractable force recovery roller at the rear of the vehicle is in functional position.       

     According to an embodiment, the motor launch vehicle is provided with a deflector capable, in an operational position, of deflecting a jet of air expelled by the drone&#39;s jet engine(s), the deflector preferably being movable between the operational position and a transport position to reduce the drag of the launch vehicle in the air, the deflector in the operational position deflecting the jet of air, preferably upwards. The deflector prevents a second vehicle, which would follow the vehicle that has just made the release, from being impacted. One can thus envisage a column of vehicles following each other at a short distance and dropping their drone one after the other before leaving the column. 
     If necessary, a front deflector may also be provided, projecting forward from the platform so as to protect the vehicle windshield. 
     The drone in the starting position preferably has a center of gravity whose vertical projection, when the vehicle is travelling in a straight line on a horizontal launch track, is located in a rectangle delimited by the contact zones between the wheels of the motor vehicle and the launch track, closer to a median transverse vertical plane between a front wheelset and a rear wheelset of the vehicle than to the front wheelset or the rear wheelset. 
     In one embodiment, the launch ramp is movable between the launch position and a transport position to reduce the drag of the launch vehicle in the air. Advantageously, the launch ramp is positioned on a roof of the launch vehicle, which preferably has an inclined rear cover allowing a rear cantilevered portion of the launch ramp to be lowered when the launch ramp moves from the transport position to the launch position. Preferably, moving from the transport position to the launch position results in a tilt of the launch ramp and/or an extension of the launch ramp. If necessary, the ramp can be motorized to ensure the passage from one position to another. It can be foreseen that the passage is only possible at a standstill. It can also be foreseen that it is possible when the motor vehicle is in motion. 
     The absence of a landing gear allows, compared to a drone with a fixed landing gear, a significant reduction in the drag of the drone, and, compared to a drone with a retractable landing gear, a considerable technical simplification, which is accompanied by greater reliability and a significant reduction in unladen weight. The absence of a landing gear also makes it possible to authorize drone launches from rough terrain and to avoid the need for landing and takeoff airstrips. 
     In one embodiment, the drone is provided with skids for sliding on the launch ramp, especially on rails or in runners on the launch ramp. The fixed and profiled skids generate a low and easily controllable drag. They are used to interface with the ramp during launch and as feet when the drone is on the ground. The skids are preferably constituted by ribs protruding slightly from the belly of the drone&#39;s fuselage, over all or part of the length of the fuselage. These ribs extend parallel to the longitudinal axis of the drone, and can be located on two planes parallel to a median longitudinal plane of the fuselage or on two planes at an angle to the median longitudinal plane of the fuselage. There are preferably two skids. 
     In another embodiment, a mobile assembly is guided all the way along the launch ramp, and means are provided for securing the drone to the mobile assembly until the drone reaches a takeoff position relative to the launch ramp, and releasing the drone from the mobile assembly when the drone reaches the takeoff position. The mobile assembly remains attached to the launch ramp after the drone takes off. 
     In one embodiment, the drone is equipped with a recovery parachute. The recovery parachute, preferably housed in a cavity in the drone, is deployed for the recovery of the drone, for example to recondition it for a new mission. 
     The drone has a fuselage and a wing. The fuselage is preferably provided with a cavity to accommodate a load. The cavity is preferably open on the back of the fuselage, i.e. on a side of the fuselage opposite to the ground at least in the launch and flight phases. The opening can, if necessary, be closed by a cover that can be released or ejected. It is also possible to provide a device for closing the cavity after the release of the load, to minimize turbulence during the drone return and recovery phase. This shutting device is preferably a lightweight device, such as a roller shutter or, preferably, an inflatable sack that can be quickly deployed and occupies all or part of the cavity by sealing the opening. 
     An additional simplification is achieved if the drone is equipped with avionics on the back allowing a stabilized flight, for a load release phase of the load lodged in the cavity of the fuselage of the drone. This avoids the need for a trap door system, which contributes to the simplicity, lightness and reliability of the system. 
     Preferably, the jet engine(s) will have sufficient thrust to ensure takeoff of the drone when the motor vehicle has reached or exceeded the required speed. Alternatively, the launch ramp can be equipped with an energy accumulator capable of impulsively releasing previously accumulated energy to catapult the drone. The energy accumulator can be scaled to allow for takeoff, in combination with the maximum thrust of the engines and the speed of the vehicle. It can also be scaled to allow for takeoff in combination with maximum engine thrust with the vehicle at rest. 
     According to one embodiment, the energy accumulator comprises one or more pneumatic energy accumulators, constituted by pressurized gas reservoirs, in particular compressed air, whose expansion in free air or in a variable-volume chamber of a pneumatic jack generates mechanical work for catapulting the drone. 
     Preferably, the energy accumulator(s) are integrated with an actuator that can modulate in real time the output flow of the energy accumulator(s), and thus the kinetic energy transferred to the drone, during the launch phase. In particular, the modulation law can impose that the instantaneous thrust on the drone remains below a given threshold, at any time during the launch phase. 
     According to another aspect of the invention, it relates to a method of transporting and dropping a load, comprising a launch of a drone carrying the load, then a flight of the drone to a drop zone, followed by a drop of the load from the drone in flight, then a flight of the drone to a recovery zone, preferably implemented by the assembly as previously defined. For the launch, a launch vehicle carrying the drone rolls on a launch track so as to exceed a given speed threshold with respect to a surrounding air mass, and the drone is guided by a launch ramp equipped with the launch vehicle from a starting position in a launch direction towards the front of the launch vehicle; the drone is propelled during the launch and at least part of the flight towards the drop zone and/or the flight to the recovery zone at least partially by one or more of the drone&#39;s engines, and the drone, having reached the recovery zone, deploys a recovery parachute and lands on the recovery area without a landing gear. 
     The piloting of the drone in the takeoff phase can be done from the vehicle, in a pre-programmed way with dedicated avionics equipment, or independently by a remote operator. 
     Preferably, the release of the load involves flipping the drone onto its back, then, by gravity, a release of the load from a cavity in the drone flying on its back, then, preferably, a deployment of a parachute to slow down the load in free fall. 
    
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
       Further features and advantages of the invention will become apparent from the following description, with reference to the attached figures, which illustrate: 
         FIG. 1 , a side view of an assembly according to a first embodiment of the invention, comprising a motor vehicle and a drone, in a transport position; 
         FIG. 2 , a front view of the assembly in  FIG. 1 , in the transport position; 
         FIG. 3 , a rear view of the assembly in  FIG. 1 , in the transport position; 
         FIG. 4 , a side view of the assembly in  FIG. 1 , in a first phase of deployment of a drone launch ramp; 
         FIG. 5 , a side view of the assembly in  FIG. 1 , in a second phase of deployment of the drone launch ramp; 
         FIG. 6 , a side view of the assembly in  FIG. 1 , in a third phase of deployment of the drone launch ramp; 
         FIG. 7 , the assembly in  FIG. 1 , in a drone launch phase; 
         FIG. 8 , a bottom view of the launch ramp and the drone in the position in  FIG. 4 ; 
         FIG. 9 , a view from below of the launch ramp and the drone, in the position in  FIG. 6 ; 
         FIG. 10 , a bottom view of the launch ramp and the drone in the position shown in  FIG. 7 ; 
         FIG. 11 , a detail view of two portions of a rail of the launch ramp with the launch ramp at maximum extension, before reaching the position in  FIG. 9 ; 
         FIG. 12 , a detail view of the two portions of the rail in  FIG. 11 , in the position in  FIG. 9 ; 
         FIG. 13 , a view of a mechanism for moving the rail portions in  FIG. 11  from the position in  FIG. 11  to the position in  FIG. 12 , the mechanism having been omitted from the preceding figures to simplify reading; 
         FIG. 14 , a side view of the drone and a mobile assembly connecting the drone to the launch ramp at the forward end of the launch ramp in the position shown in  FIG. 7 ; 
         FIG. 15 , a front view of the drone and of the mobile assembly linking the drone to the launch ramp; 
         FIG. 16 , a detail of  FIG. 15  allowing a visualization of a locking mechanism of the drone in relation to the mobile assembly; 
         FIG. 17 , a view from below of the mobile assembly and a mechanism for locking the mobile assembly to the launch ramp in the starting position of  FIGS. 5 and 6 ; 
         FIG. 18 , a bottom view of the mobile assembly at a forward end of the launch ramp, and a release mechanism for releasing the locking mechanism between the mobile assembly and the drone in the position in  FIG. 7 ; 
         FIG. 19 , a bottom view of the launch ramp and the drone in the position in  FIG. 4 , according to a variant constituting a second mode of realization of the invention; 
         FIG. 20 , a bottom view of the launch ramp and the drone according to the second embodiment of the invention, in the position in  FIG. 5 ; 
         FIG. 21 , a front view of the drone and of a mobile assembly linking the drone and the launch ramp, according to a variant constituting a third use of the invention; 
         FIG. 22 , a detail of  FIG. 21  allowing a visualization of a locking mechanism of the drone in relation to the mobile assembly; 
         FIG. 23 , a bottom view of the mobile assembly in  FIG. 21  at a forward end of the launch ramp, and a release mechanism for releasing the locking mechanism between the mobile assembly and the drone in the position in  FIG. 7 ; 
         FIG. 24 , a front view of the drone and of a connection between the drone and the launch ramp according to a variant constituting a fourth mode of implementation of the invention; 
         FIG. 25 , a diagram of the different phases of a transport and release mission for a load by means of the assembly according to  FIGS. 1 to 4 , after the launch of the drone according to the launching phases in  FIGS. 4 to 7 ; 
         FIG. 26 , an axial sectional view of a pneumatic energy storage actuator, integrated into a catapult for launching the mobile assembly and the drone on the launch ramp during the drone launch phase illustrated in  FIG. 7 , in a first position of modulation of a catapulting force; 
         FIG. 27 , an axial sectional view of the actuator in  FIG. 26 , in a second modulation position; 
         FIG. 28 , an axial cross-sectional view of a pneumatic energy storage actuator constituting an alternative to the actuator in  FIG. 26 , in a first modulation position; 
         FIG. 29 , an axial sectional view of the actuator in  FIG. 28 , in a second modulation position; 
         FIG. 30 , an axial sectional view of a pneumatic energy storage actuator constituting an alternative to the actuators in  FIGS. 26 to 29 , in a first modulation position; 
         FIG. 31 , a cross-sectional view of the actuator in  FIG. 30 , in the first modulation position; 
         FIG. 32 , a cross-sectional view of the actuator in  FIG. 30 , in a second modulation position; 
         FIG. 33 , an axial sectional view of a pneumatic energy storage actuator constituting an alternative to the actuators in  FIGS. 26 to 32 ; 
         FIG. 34 , an axial sectional view of a pneumatic energy storage actuator constituting an alternative to the actuators in  FIGS. 26 to 33 ; 
         FIG. 35 , an axial cross-sectional view of a pneumatic energy storage actuator with a trigger that can also be optionally implemented in the actuators in  FIGS. 26 to 34 , in a pre-firing position; 
         FIG. 36 , an axial cross-sectional view of the actuator in  FIG. 35 , in a post-actuation position; 
         FIG. 37 , an axial cross-sectional view of a telescopic actuator, showing a telescopic mechanism that can also be integrated with the actuators in  FIGS. 26 to 36 , in a retracted position; 
         FIG. 38 , an axial cross-sectional view of the telescopic actuator in  FIG. 37 , in a deployed position; 
         FIG. 39 , an axial cross-sectional view of a pneumatic energy storage actuator as an alternative to the actuators in  FIGS. 26 to 38 . 
     
    
    
     For the sake of clarity, identical or similar elements are marked with identical reference signs throughout the figures. 
     DETAILED DESCRIPTION OF EMBODIMENTS 
       FIGS. 1 to 3  illustrate an assembly  10  comprising a launch vehicle  12  and a drone  14 . The motor vehicle  12  is able to travel at high speed on prepared or paved tracks, and preferably also on unprepared and unpaved tracks. The motor vehicle  12  shown here is a four-wheeled light-duty all-terrain utility vehicle  16 A,  16 B, but a motor vehicle of another type is also useable. 
     The motor vehicle  12  is equipped, on its roof  18 , with a fixed frame  19  supporting a launch ramp  20  to which the drone  14  is coupled. The launch ramp  20  here constitutes in particular a mobile frame  21  supporting two parallel rails  22  to guide the drone  14  on a rectilinear launch trajectory. 
     The launch ramp  20  is preferably mobile relative to the fixed frame  19  between a transport position, shown in  FIG. 1 , and a launch position shown in  FIGS. 6 and 7 , passing through various deployment phases, shown in  FIGS. 4 through 6 . In practice, the mobile frame  21  of the launch ramp is hinged to the fixed frames  19  mounted on the roof  18  of the motor vehicle  12  via a hinge  23 , to pivot about a horizontal transverse pivot axis. In the launch position (and preferably in the transport position), the drone  14  points toward the front of the motor vehicle  12 . In the transport position, the launch ramp  20  is positioned horizontally, to reduce the drag coefficient of the motor vehicle  12  in the air. 
     The transition from the transport position to the launch position is carried out by pivoting the launch ramp  20  about the horizontal transverse pivot axis defined by the hinge  23 , using a hydraulic, pneumatic or electromechanical cylinder  24 . 
     The actuator  24  can be placed directly between the fixed frame  19  and the launch ramp  20 . Alternatively, we can predict, as shown in  FIGS. 5 to 7 , an actuator  24  attached to the fixed frame  19  and driving a mechanism  124  for transmitting motion from the actuator  24  to the launch ramp  20 , which ensures that in the launch position, forces applied to the launch ramp  20  are only transmitted to the actuator  24 . We can for example predict a connecting rod  124  may be provided, one end of which is articulated to a rod of the actuator  24  and is guided in translation parallel to the horizontal axis of the rod of the actuator  24 , and the other end of which is articulated to the mobile frame  19  or to a crosspiece connecting the two rails  22  of the launch ramp  20 . The angle between the connecting rod  124  and the actuator  24  has been represented as an obtuse angle in  FIGS. 5 to 7 , but may optionally be a right angle, to further reduce or even cancel the forces on the launch ramp  20  through to the actuator  24  in the launch position, or even an acute angle, which allows, by providing an end-of-travel stop for the rod of the actuator  24 , the forces exerted by the ramp  20  on the connecting rod  124  at the end-of-travel stop to be fully taken up. 
     The pivot axis of the joint  23  is preferably located within the lift rectangle of the motor vehicle  12 , i.e., between the rear wheel assembly  16 A and the front wheel assembly  16 B of the motor vehicle, and at a distance from the longitudinal ends of the launch ramp  20 , so that when the launch ramp  20  tilts, a rear end of the launch ramp  20  lowers while a front end of the launch ramp  20  raises. Advantageously, the motor vehicle  12  may have a sloped rear hood  25  that allows the cantilevered rear end of the launch ramp  20  to lower as the ramp moves from the transport position to the launch position. 
     The launch ramp  20  may optionally be equipped with a retractable undercarriage  26 , hinged near the rear end of the launch ramp  20  and driven by an actuator  126 , to move from a retracted position shown in  FIG. 1  to a deployed position shown in  FIG. 4 . The retractable undercarriage  26  has at least one, and preferably two, wheels  27  which, in the inclined position of the ramp  20  shown in  FIGS. 5 to 7 , can be positioned at a short distance from the ground, or, according to a variant not shown, can roll on the ground. 
     As illustrated in detail in  FIGS. 8 to 10 , the rails  22  of the launch ramp  20  are preferably in at least two parts  22 A,  22 B movable relative to each other, so as to permit extension of the front part of the launch ramp  20  in the launch position ( FIGS. 6, 7, 9 and 10 ) and retraction in the transport position ( FIGS. 1 and 8 ). 
     Preferably, the rear portion  22 A of the rails is fixed with respect to the movable frame  21 , or forms one unit with the movable frame  21 , so as to pivot about the axis of the joint  23 , and connected to the actuator  24 , for example via the connecting rod  124 , as illustrated in  FIGS. 5 to 7 . A front part  22 B of the rails is movable with respect to the rear part  22 A so as to be retracted in transport position and deployed in launching position. 
     The rear  22 A and front  22 B parts of each rail are placed side by side in the transport position, as shown in  FIG. 8 . The movement of the front part  22 B of the rails is a longitudinal translation, guided by the mobile frame  21  and/or the rear part  22 A of the rails, to a maximum extension position shown in  FIG. 11 . To align and lock the front rail part  22 B with the rear rail portion  22 A, the front rail portion  22 B is transversely displaced, allowing locking pins  122 A integral with the front end of the rear rail portion  22 A to engage complementary locking slots  122 B at the rear end  222 B of the front rail portion  22 B, as illustrated in  FIGS. 9 and 12 . This locking movement can be carried out by an operator, or preferably by an optional mechanism  322  illustrated in  FIG. 13 , comprising an actuator  322 . 1  linked to the rear end  222 B of the front part  22 B of the rails by connecting rods  322 . 2 . 
     Each rail part  22 A,  22 B is a hollow section  60  within which is a runner shown in  FIG. 16 . In the launch position, the two parts  22 A,  22 B of each rail  22  are perfectly aligned, and the runners  60  of the two parts  22 A,  22 B of the same rail  22  are in line with each other without discontinuity. The connection between the drone  14  and the launch ramp  22  is made, in this first mode of realization, by means of a mobile assembly  62  illustrated in  FIGS. 14 to 18 , and voluntarily omitted on the preceding figures to simplify reading. The mobile assembly  62  comprises a frame  64  of a generally rectangular shape, two lateral skids  66  sliding in the runners formed between the two parallel rails  22  of the launch ramp  20 , and four clamps  68 , which clamp two legs  28  of the drone, each formed by a longitudinal rib parallel to the main axis of the fuselage and projecting under the belly of the fuselage, at a distance from the main plane of symmetry of the fuselage. Each clamp  68  has a fixed jaw  70  and a movable jaw  72  biased toward a clamping position by a return spring  74 , and integral with a retracting finger  76 . 
     The mobile assembly  62  is free to translate relative to the launch ramp  20  as the skids  66  slide in the runners  60 . However, locking mechanisms are provided in two predefined positions, namely in the transport position in  FIG. 1 , and in the armed position in  FIGS. 5 and 6 , set back from the transport position towards the rear of the launch ramp  20 .  FIG. 17  shows the locking mechanism  77  for locking in the transport position, which has a locking bolt  78  for each rail  22  controlled by an actuator  80 . For example, the locking bolt  78  can be guided in transverse translation, and returned to an unlocking position by a return spring  82 , the actuator  80  being here an actuator connected to the locking bolt  78  by a lever  84 . The locking bolt  78  in the locked position is housed in a bore constituting a strike plate  86  formed in the corresponding skid  66  of the mobile assembly  62 . The same locking mechanism is provided for the armed position in  FIGS. 5 and 6 . 
     In the transport position in  FIG. 1 , and the launch phases illustrated in  FIGS. 5 and 6 , until reaching the position in  FIG. 7 , the clamps  68  are closed, ensuring the attachment of the drone  14  to the mobile assembly  62 . Upon reaching the position in  FIG. 7 , the heads of the retracting fingers  76  engage cams  88  at the front end of the front rail portions  22 B and shown in  FIG. 18 , so that the movable jaws  72  open, releasing the drone  14 . 
     Indeed, the drone  14  is jet-powered, comprising one or more engines  30  giving it significant thrust, for example one or two engines each delivering thrust greater than 400 Newtons, preferably greater than 600 N. If more than one engine is provided, the power of each is preferably sufficient to allow for flight at less than full power. The motor vehicle  12  is provided with a deflector  32  adapted, in an operative position illustrated in  FIGS. 5 to 7 , to deflect a jet of air expelled by the jet engine(s)  30  of the drone  14 , preferably upwardly. Preferably, the deflector  32  is movable between the functional position in  FIGS. 5 to 7  and the transport position shown in  FIG. 1 , to improve the movement of the motor vehicle  12  in the air. If necessary, the deployment of the deflector  32  and that of the wheelset  26  can be simultaneous and carried out by the same actuator  126 . 
     The drone  14  has a fuselage  34  and a wing  36 , the wing preferably with a wingspan greater than 2 meters, and preferably greater than 2.5 meters, so that the wingspan is potentially greater than the track width of the vehicle  12 . In a variant not shown, the wing has a variable geometry, to be folded in transport position to minimize the overall width of the assembly, and deployed for launch. 
     If necessary, it may be possible to equip the launch ramp  20  with a catapult  90  illustrated in  FIGS. 8 to 10 . Such a catapult  90  includes an actuator  92  that may include an energy accumulator capable of impulsively releasing previously accumulated energy to accelerate the drone  14  from the armed position in  FIG. 5  to the release position in  FIG. 7 . The energy accumulator is preferably an elastic potential energy accumulator (a spring mechanism) or a chemical energy accumulator (a pyrotechnic device), or even a pneumatic energy accumulator. Preferably, the actuator  92  acts on a translationally guided transmission member  94  to transmit the kinetic energy released by the energy accumulator  92  to the drone  14 . In the figures, the actuator  92  is a pyrotechnic device, and the transmission member  94  is constituted by a piston linked to a rod  94 B itself linked to a head  94 C, bearing against a rear shoulder  28 C (visible in  FIGS. 4 and 7 ) of the pads  28 . It is also possible to consider assisting the launch with a rocket, from which the drone  14  separates after takeoff. 
     To launch the drone  14  from the transport position in  FIG. 1 , the undercarriage  26  and deflector  32  are first deployed to the position in  FIG. 4 , and then the launch ramp  20  is pivoted to the position in  FIG. 5 , releasing the locking mechanism  77  that held the mobile assembly  62  and the drone  14  relative to the launch ramp  20  in the transport position. The drone, driven by its weight, moves backwards on the launch ramp  20  until it reaches the position illustrated in  FIG. 5  resting against the head  94 C of the catapult  90 . The locking mechanism  77  corresponding to this position locks the mobile assembly  62  and the drone in the armed position. The front portion  22 B of the rails  22  of the launch ramp  20  is deployed to the position shown in  FIG. 6 . The deployment phases of  FIGS. 4, 5 and 6  can be carried out while the vehicle is stationary, if necessary manually, or automatically, and if necessary while the vehicle  12  is moving. The order of operations can also vary: in particular, the deployment of the front part  22 B of the rails  22  can be carried out while the launch ramp  20  is still horizontal. 
     Ultimately, after the deployment of the front part  22 B of the rails  22 , the motor vehicle is brought to a speed exceeding a predetermined threshold with respect to the surrounding air mass, to proceed with the actual launch of the drone  14 . The engines  30  of the drone  14  are powered at low power or at least at a power higher than a predetermined threshold depending on the wind and loading conditions. Finally, the actuator  80 , which is preferably an electromagnetic actuator, releases the locking mechanism  77  blocking the mobile assembly  62 , while simultaneously the energy accumulator  92  of the catapult  90  is triggered, so that the drone, driven by the catapult  90  and the reactors  30 , advances on the launch ramp  20 , still linked to the mobile assembly  62 . When reaching the front end of the launch ramp, the cams  88  open the clamps  68  which release the drone which takes off. If necessary, the undercarriage  26  contributes to the stability of the motor vehicle  12  during the launch, in particular by taking up the recoil forces of the catapult  90 . 
     The catapult  90  is optional if the dimensioning of the engines  30  is sufficient to ensure the takeoff. If necessary, the catapult  90  may allow the drone  14  to be launched when the motor vehicle  12  has not reached a sufficient speed to allow takeoff using only the engines  30 , or may allow the duration of the power supply to the engines  30  to be limited to full power, thus increasing the range of action. If the energy stored by the catapult  90  is sufficient, the launch can also be initiated while the motor vehicle  12  is stationary. 
     According to the variant of the  FIGS. 19 and 20 , the front part  22 B of the rails  22  of the launch ramp  20  is connected to the rear part  22 A by a joint  22 C, which allows the deployment of the front part  22 B by pivoting from the folded position illustrated in  FIG. 19  to the deployed position in  FIG. 20 . This deployment can advantageously be carried out while the launch ramp  20  is still horizontal. It can of course be motorized. 
     According to the variant of realization of  FIGS. 21 to 23 , the mobile assembly  62  comprises four independent rollers  166 , which come to roll, according to the conditions of bearing capacity during the launching phase, alternately on upper tracks  160  or lower tracks  260  formed between the rails  22 . Each roller  166  pivots on an axis that forms a finger  176 , a free end of which engages a bore  276  in a corresponding foot  28  of the drone  14 , to connect the drone  14  to the roller  166 . 
     At the front end of the front portions  22 B of the rails  22 , a slight deflection of the running tracks  160 ,  260  clears the fingers  176  and releases the drone  14  for flight, as shown in  FIG. 23 . 
     According to the embodiment shown in  FIG. 24 , the feet  28  of the drone  14  form skids that slide in runners  29  on the rails  22  of the launch ramp  20 , the runners  29  being oriented so as to form together or separately a connection leaving the drone  14  only one degree of translational freedom with respect to the launch ramp  20 . Advantageously, the runners  29  can be equipped with a friction-limiting covering or with rollers (not shown) on which the skids  28  roll. The drone  14  separates from the launch ramp  20  at its end when the skids  28  are released from the runners  29 . 
     The fuselage  34  of the drone  14  has a cavity for carrying  38  a load  40 , which is preferably a load intended to be dropped. The transport cavity  38  is preferably open on the back of the fuselage, i.e., on a side of the fuselage opposite the ground at least in the takeoff ( FIG. 25 , A) and flight ( FIG. 25 , B) phases. The transport cavity  38  can be closed by a cover  42  that can be ejected or jettisoned, to optimize the thinness of the fuselage  34 . To minimize the unladen weight and to limit the risks of failure, a simplified fuselage structure, not comprising an articulated door to release the load  40 , has been voluntarily chosen. Therefore, to assure the airdrop of the load  40  in flight, an ejection of the cover  42  is foreseen ( FIG. 25 , C), followed by the turning of the drone  14  on its back and the release of the load  40  ( FIG. 25 , D). The airdrop of the load  40  may be accompanied by the deployment of the parachute  44  to slow down the load  40 , allowing it to reach the target zone  46  without any problems. If necessary, the drone can be equipped with a shutting device  48 , for example an inflatable bag or a rolling shutter, which is deployed so as to fill the cavity, or at least to close the opening, and to reconstitute continuity with the walls of the fuselage during the length of the flight ( FIG. 25 , E), after release, towards a recovery area  50  of the drone. 
     Indeed, the drone  14  has no landing gear, which contributes to its low drag. To assure its landing, the drone  14  is equipped with a recovery parachute  52  which is able to deploy upon shutdown of the engines  30  upon reaching the recovery area  50  ( FIG. 25 , F). 
     A cycle of how the drone  14  is used can thus be broken down as follows:
         a launch ( FIGS. 5 to 7 ) and takeoff ( FIG. 25 , A) phase, from the motor vehicle  12  running on a launch track above a given speed threshold with respect to a surrounding air mass, during which phase the drone  14  is propelled by its jet engine(s)  30 , if necessary assisted by a catapult, and guided by   the launch ramp  20  from a starting position in a launch direction towards the front of the motor vehicle  12 ,   a flight phase ( FIG. 25 , B) propelled by the jet engines  30  to a drop zone  46 ,   if necessary, the ejection or drop of the cover  42  ( FIG. 25 , C),   then, the drone  14  is turned on its back and the load  40  is released due to gravity ( FIG. 25 , D) with, if necessary, the deployment of a parachute for slowing down  44  the load, implemented automatically or with a delay,   turning the drone  14  on its belly ( FIG. 25 , E) for a flight phase of the drone, with a possible shutting of the cavity  38  through a shutting device  48  up to a recovery zone,   stopping or significantly slowing down the jet engines  30  and deploying the recovery parachute  52 , to land the drone on its belly, without a landing gear, in a recovery area  50  ( FIG. 25 , F).       

     Alternatively, the launch phase can take place at standstill, the initial kinetic energy being obtained by combining the jet engines  30  and the catapult  90 , if the latter is sufficiently powerful. 
     Alternatively, the transport cavity  38  is open not on the back of the fuselage, but on the belly, and closed by a cover  40  which is positioned between the skids  28 . This variant limits the width of the opening  38 , but avoids the turning maneuver for the airdrop. 
     The launch and takeoff phases of the drone can be controlled from the motor vehicle  12 , by an operator with a man-machine control interface, connected by wired or wireless connection to various sensors on the motor vehicle  12  (in particular one or more of the following sensors: motor vehicle speed sensor  12 , speed and direction sensor of the apparent wind, launch ramp position sensors  20 ) and on the drone  14 , and to actuators on the locking mechanism  77  and the drone  14  in order to drive them. It can also be controlled remotely. 
       FIGS. 26 through 38  illustrate various embodiments of a pneumatic energy accumulator actuator  92  that can be integrated with the catapult  90  on the launch ramp  20  shown in  FIGS. 8 through 10 . These embodiments have in common a transmission unit  94  constituted by a piston  94 A linked to a rod  94 B intended to be connected to the drone  14 , for example by the intermediary of the head  94 C, illustrated on  FIGS. 8 to 10 , coming to bear against a rear shoulder  28 C (visible in  FIGS. 4 and 7 ) of the skids  28 . The piston  94 A slides concealed in a cylindrical body  921  of the actuator, which delimits a variable volume chamber  922  and forms with the piston  94  and the rod  94 B a pneumatic cylinder. 
     According to a first embodiment illustrated in  FIGS. 26 and 27 , the variable volume chamber  922  communicates with one or more pressurized pneumatic accumulators  924  via one or more supply lines  925 , an optional balancing chamber  926 , and a modulating valve  930 . The modulating valve  930  includes a pilot chamber  931  that communicates with the balancing chamber  926  or supply lines  925  through one or more flow ports  932  and with the variable volume chamber  922  through a supply port  933 . A movable modulator  934  is positioned in the pilot chamber  931  and driven by a control actuator  935  so as to be movable between a maximum opening position shown in  FIG. 26  and a minimum opening position, shown in  FIG. 27 . The control actuator  935  can be pneumatic, hydraulic or electric. 
     In this embodiment, the movable modulator  934  is a modulator spool that can be moved in translation between the minimum and maximum opening positions, for example along an axis coinciding with the translation axis of the piston  94 A. However, other orientations of the translation axis of the modulating spool  934  with respect to the translation axis of the piston  94 A can be considered. The control actuator  935  is linear and coaxial with the translation axis of the modulator spool  934 , and connected to it by a rod  936 . 
     The movable modulator  934 , in its minimum opening position, constitutes a significant pressure drop opposing the flow of compressed gas from the pneumatic accumulators  924  to the variable volume chamber  922 . As it moves away from the minimum opening position towards the maximum opening position, the movable modulator  934  retracts and the pressure drop it generates decreases according to a law that may or may not be linear depending on the distance covered. 
     It can be seen that the mobile modulator  934  here is frustoconical in shape corresponding to the frustoconical shape of the part of the control chamber  931  into which the passage orifices  932  open. If applicable, the shape of the movable modulator  934  or the shape of the passage openings  932  may be selected so that a linear change in the position of the movable modulator  934  results in a linear or non-linear change in the pressure drop generated by the movable modulator  934 . 
     Although passages  937  are provided between the part of the pilot chamber  931  into which the passage ports  932  and the supply port  933  open and the part of the pilot chamber  931  between the movable modulator  934  and the control actuator  935 , the pressurized gas in the pilot chamber induces  931  a differential force on the movable modulator  934  pushing the movable modulator towards the  934  maximum open position, a force which is an increasing function of the prevailing pressure in the pilot chamber  931 . Preferably, a balancing spring  938  biases the movable modulator  935  toward the minimum open position and at least partially balances this force. 
     Preferably, the control actuator  935  allows the movable modulator  934  to stably assume any desired intermediate position between the minimum opening position of the maximum opening position, so as to generate a variable pressure drop between the flow ports  932  and the variable volume chamber  922 . If applicable, the control actuator  935  may comprise an irreversible mechanism, in the sense that no holding energy is required to maintain the control actuator  935  and the movable modulator  934  in any position between the minimum opening position of the maximum opening position, regardless of the forces applied to the movable modulator  934 . 
     The aim is to obtain in the variable volume chamber  922  a pressure and a flow that follow a predetermined law as a function of the course of the piston  94 A from the armed position in  FIG. 5  to the release position in  FIG. 7 , in order to transfer to the drone  14  the kinetic energy necessary for takeoff, without exceeding a predetermined threshold of instantaneous acceleration the structure of the drone  14  and the on-board equipment can bear. 
     For this purpose, the control actuator can be a proportional control actuator, implementing a control loop with respect to a set-point signal which can be, for example, a piston position, speed or acceleration signal, or a moveable modulator position, speed or acceleration signal. 
     Alternatively, the control actuator  935  may be set to a constant rhythm between two end positions during the launch of the drone  14 , with the shape of the flow ports  932  and the movable modulator  934  imposing the desired flow law. 
     Optionally, an auxiliary supply port  927  of the variable volume chamber  922  connected to an auxiliary pressure source  928  via a solenoid valve  929  is foreseeable, the latter being closed as long as the piston  94 A is upstream of the auxiliary supply port  927  and opening as soon as the piston  94 A passes downstream of the auxiliary supply port  927  so as to increase the flow entering the variable volume chamber  922  in the last part of its course. 
     When the drone  14  is in the armed position in  FIGS. 5 and 6 , locked by the corresponding locking mechanism  77 , and an operator gives a command to launch the drone, the control actuator  935  positions the movable modulator  934  in a desired initial position, while the locking mechanism  77  is kept locked. The volume of the variable volume chamber is minimal and the pressure inside is equal to the pressure of the pneumatic accumulators  924 . 
     Then, the actuator  80  causes the locking bolt  78  to retract, releasing the mobile assembly  62 . The pressure in the variable volume chamber  922  pushes back the piston  94 A and a stream of pressurized gas is supplied to the variable volume chamber  922  with a flow rate controlled by the movable modulator  934  whose position is continuously adapted so that the acceleration of the mobile assembly  62  remains below a predetermined threshold. The launch phase lasts less than a second, and the control actuator  935  is scaled to have an appropriate response time, allowing for flow modulation to regulate the acceleration of the drone  14  in real time. 
     The embodiment shown in  FIGS. 28 and 29  differs from the previous one in the shape of the mobile modulator  934 , which is here an axially sliding spool in the control chamber  931  and equipped with through bores  939 . The pilot chamber  931  is largely open to the variable volume chamber  922  and can be considered part of it. The spool  934  is attached to a rod  936  of a control linear actuator  935  that allows the position of the spool  934  to be varied between a maximum open position shown in  FIG. 28 , in which the through bores  939  are largely aligned with the passage ports  932 , and a minimally open or even closed position shown in  FIG. 29 , in which the overlap between the through bores  939  and the passage ports  932  is minimal or non-existent. The shape of the through bores  939  and the passage ports  932  can be adapted to determine a linear or non-linear law of variation of the through bore cross-section as a function of the course of the spool  934 . 
     A balancing spring  938  biases the spool  934  toward the maximum open position in  FIG. 28 . 
     The embodiment in  FIGS. 30 to 32  differs from the preceding ones in that the movable modulator  934  is a rotary valve driven by a rotary control actuator  935 , which rotates one-eighth of a revolution between a maximum open position shown in  FIGS. 30 and 31  and a minimally open position shown in  FIG. 32 , which may optionally be a closed position. 
       FIG. 33  shows a variant of the previous embodiments, in which each of the supply lines  925  opens directly into the variable volume chamber  922  and is equipped with a modulating valve  930 , which may be of the type previously described or a commercial solenoid valve. It is then possible to operate the modulating valves  930  simultaneously or successively, and more generally, with two different behavior laws to optimize the compressed air flow into the variable volume chamber  922 . 
       FIG. 34  illustrates another embodiment, in which the modulation of the flow rate into the variable volume chamber  922  is achieved passively, without a control actuator  935 . For this purpose, the part of the control chamber  931  opposite the variable volume chamber  922  communicates with a modulation chamber  940  through calibrated bores  941 . The calibration of the calibrated holes  941 , the spring setting  938 , the dimensions of the passage ports  932  and the shape of the movable modulator  934  are then chosen so that the dynamic behavior of the mobile modulator during piston expansion conforms to the desired law. 
       FIGS. 35 and 36  illustrate an accessory which is usable in all the preceding embodiments and which consists of a retaining rod  942  connecting the piston  94 A to the cylindrical body  921 , this rod comprising a breakable portion  943  calibrated in such a way as to yield when the pressure exerted on the piston  94 A exceeds a predetermined threshold, as illustrated in  FIG. 36 . 
     In  FIGS. 37 and 38 , an embodiment is shown in which the actuator  92  of the catapult  90  is a telescopic actuator, for increased compactness, the variable volume chamber  922  being formed by one or more coaxial nested tubes  944 ,  945 ,  946  of decreasing diameters initially positioned within a tubular, cylindrical body  921 . This arrangement can be implemented in all previously described variants of the actuator  92 . 
       FIG. 39  illustrates a catapult  90  that is integrated with the frame  64  of the mobile assembly  62  as shown in  FIGS. 14 through 18 . Tubes  950  with a closed bottom  951  at one end are attached to the frame, and the opposite end  952  is open and hermetically attached  953  to a holding base  64 . 
     Filling ports  954  allow a compressible fluid, in this case pressurized air, to be injected into the tubes  950 . The frame  64  is held in the armed position by a hydraulically or pneumatically operated locking mechanism  77 . As soon as the locking mechanism  77  releases the frames  64 , the pressure exerted on the bottoms  951  of the tubes  950  projects the frames  64  and the mobile assembly  62  carrying the drone  14  onto the launch ramp  22 . The tubes  950  may have different capacities and diameters from each other, and the open ends  952  may also have different opening cross-sections from each other. 
     In all embodiments of the actuator  92 , a shock absorber is provided at the end of the launch path, which may incorporate an elastomeric block, a gas damper, a spring, or any other suitable device. 
     Of course, the examples shown in the figures and discussed above are only illustrative and non-restrictive. It is explicitly foreseen that the various illustrated embodiments can be combined with each other to provide further embodiments.