Aerostat

Abstract

Aerostat (100) comprising a first balloon (10a) and a second balloon (10b) extending in a longitudinal direction (X), a connecting structure (30) configured to maintain the first balloon and the second balloon relative to each other. The connecting structure (30) comprises, for each of the first and second balloons, a first frame (31a, 31b) connected to one of the balloons of said first and second balloons, said first frame having substantially the shape of the envelope in a transverse plane (YZ) of said balloon to which said first frame is connected, and partially surrounding this envelope externally, and a first cross member (32) which connects the first frame of the first balloon and the first frame of the second balloon in a lateral direction (Y). Figure for the abbreviation: FIGURE 1

Description

Title of the invention: Aerostat technical field

[0001] The present invention relates to aerostats. STATE OF PRIOR ART

[0002] More particularly, the invention relates to an aerostat comprising:

[0003] - a first balloon and a second balloon which extend in a direction longitudinal, each balloon consisting of an envelope containing a gas lighter than air,

[0004] - a linking structure configured to hold the first balloon and the second balloons in relation to each other.

[0005] Patent document WO 2004 / 016503 shows an airship with two non-rigid envelopes connected by a connecting structure to form a catamaran shape. The connecting structure may include tubular composite elements. Description of the invention

[0006] The present disclosure is intended to further improve aerostats comprising two balloons.

[0007] For this purpose, the present disclosure relates to an aerostat, in which the connecting structure comprises:

[0008] for each of the first and second balloons, a first frame connected to one of the balloons of said first and second balloons, each of the first frames having substantially the shape of the envelope in a transverse plane of said balloon to which the first frame is connected, and partially surrounding this envelope externally, said first frames being positioned in a first longitudinal position in the longitudinal direction, and

[0009] - a first cross member which connects the first frame of the first balloon and the first frame of the second balloon in the lateral direction, said first crossbar fixing the position of the balloons in the lateral direction.

[0010] Thanks to these arrangements, the balloons are perfectly held by the first frame of the first balloon and by the second frame of the second balloon.

[0011] These first frames correctly conform, from the outside, to the shape of the balloons in a transverse plane, which ensures effective support of the first and second balloons.

[0012] These first frames, partially surrounding the balloons, can support the static lift (aerostatic) in the vertical direction, towards the top of the aerostat, generated by the gas lighter than air.

[0013] These first frames allow the use of a plurality of means of fixing between the first frames and the balloons, along these first frames, which improves the holding of the two balloons.

[0014] In various embodiments of the device according to this disclosure, one and / or the other of the following provisions may also be used.

[0015] According to one aspect, the first frames have a C shape, the first frame connected to the first balloon and the first frame connected to the second balloon are oriented in opposition, an opening of each first frame being oriented towards the outside of the aerostat to accommodate respectively the first and second balloons, a body of each first frame being oriented towards the inside of the aerostat to be connected by the first cross member.

[0016] According to one aspect, the first C-shaped reinforcements extend along an angular sector between 20 degrees and 270 degrees around the envelope of each balloon.

[0017] According to one aspect, an upper end zone of each balloon is covered by said first reinforcement in order to support said first and second balloons in a vertical upward direction.

[0018] According to one aspect, each of the first armatures is fixedly connected to a balloon at a plurality of fixing points, in a number greater than 2, along said balloon, to distribute a fixing stress of the first armature on the envelope of the balloon.

[0019] According to one aspect, the plurality of fixing points is in a number greater than or equal to 3 and less than or equal to 5.

[0020] According to one aspect, each attachment point comprises a first reinforcement attachment inserted between the envelope and an external attachment layer enclosing said attachment, and said external layer being attached to the envelope by a process of gluing, sewing, plastic welding, or a combination of these processes.

[0021] According to one aspect, the linking structure further comprises:

[0022] - a first lower rod connecting directly or indirectly to a lower point of the first frame of the first balloon and the first crossbar, and

[0023] - a second lower rod connecting directly or indirectly to a lower point of the first frame of the second balloon and the first crossbar.

[0024] According to one aspect, the first lower rod and the second lower rod are rigid, elastic or elastic with damping.

[0025] According to one aspect, a connecting element makes a rigid fixed connection between the first reinforcement and the first cross member or a hinged connection between the first reinforcement and the first cross member.

[0026] According to one aspect, the aerostat further comprises an tail assembly connecting the first balloon and the second balloon in a longitudinal tail assembly position in the longitudinal direction, said longitudinal tail assembly position being different from the first longitudinal position.

[0027] According to one aspect, the first cross member is equipped with a first propulsion device.

[0028] According to one aspect, the first propulsion device is orientable by pivoting around a lateral direction axis to be oriented angularly between a horizontal propulsion position and a vertical propulsion position.

[0029] According to one aspect, the linking structure comprises:

[0030] for each of the first and second balloons, a second frame connected to one of the balloons of said first and second balloons, each of the second frames having substantially the shape of the envelope in a transverse plane of said balloon to which said second frame is connected, and partially surrounding this envelope externally, said second frames being positioned in a second longitudinal position in the longitudinal direction, different from the first longitudinal position, and

[0031] - a second crossbar which connects the second frame of the first balloon and the second frame of the second balloon in the lateral direction, said second crossbar fixing the position of the balloons in the lateral direction. Brief description of the drawings

[0032] Other features and advantages of the disclosure will become apparent during the following description of one of its embodiments, given by way of non-limiting example, with regard to the accompanying drawings.

[0033] On the drawings:

[0034] - [Fig. 1] is a perspective view of an aerostat according to the present disclosure,

[0035] - [Fig.2] is a front view of the aerostat of [Fig.1],

[0036] - [Fig. 3] is a top view of the aerostat of [Fig. 1], and

[0037] - [Fig. 4] is a front view of the aerostat linkage structure of Figures 1 to 3, and

[0038] - [Fig. 5] is a front view of a variant of the connection structure of an aerostat, And

[0039] - [Fig.6] is a cross-sectional view of an XZ plane of the aerostat of [Fig.1].

[0040] In the different figures, the same numerical references designate identical or similar elements.

[0041] The figures include a longitudinal direction X, a lateral direction Y perpendicular to the longitudinal direction X, and a vertical direction Z perpendicular to the two preceding ones. The aerostat moves primarily along the longitudinal direction X. The vertical direction Z corresponds to an upward direction of elevation. DETAILED DESCRIPTION

[0042] Figures 1 to 3 illustrate an example of Aerostat 100 according to this disclosure. Aerostat 100 comprises:

[0043] - a first balloon 10a and a second balloon 10b which extend in a direction longitudinal X, each of the balloons consisting of an envelope containing a gas lighter than air,

[0044] - a linking structure 30 configured to hold the first balloon and the second ball in relation to each other.

[0045] Such an aerostat can be named a catamaran-type aerostat (with two balloons), by analogy to a boat with two floats.

[0046] The aerostat 100 may comprise a first balloon 10a and a second balloon 10b, or more than two balloons, arranged successively in a lateral direction Y, or possibly arranged in the lateral direction Y and the vertical direction Z. In particular, in the transverse plane YZ, the balloons may be arranged in a staggered pattern. For the sake of simplicity, the following description will use a two-balloon configuration as a non-limiting example.

[0047] The first balloon 10a and the second balloon 10b extend in longitudinal direction X between a nose 101 of the aerostat 100 located towards the front in this longitudinal direction X and a tail 102 of the aerostat 100 located towards the rear of the aerostat in a direction opposite to the longitudinal direction X. By extension, the term nose or tail will also be used for each balloon 10a, 10b or the envelopes of these balloons.

[0048] Each balloon 10a, 10b has a substantially ovoid shape with a large length in the longitudinal direction X.

[0049] By convention, as shown in [Fig.2], we will consider:

[0050] - an upper portion lOas, lOab respectively of the first and second balloons 10a, 10b, each upper portion corresponding to the upper half of the balloon in question, and above a horizontal plane H, and

[0051] - a lower portion lOai, lObi of the first and second balloons 10a, 10b, each lower portion corresponding to the lower half of the balloon in question, and below a horizontal plane H.

[0052] Similarly, each balloon 10a, 10b includes a vertex or vertex line Sa, Sb corresponding to the upper line of the balloon considered between the nose 101 and the tail 102 of this balloon.

[0053] The first balloon 10a and the second balloon 10b are flexible or semi-rigid balloons. Such balloons are called non-rigid because they do not have a rigid structure that maintains the shape of the envelope containing the lighter-than-air gas. The shape of the envelope of a flexible or semi-rigid balloon is determined by the pressure of the gas inside the balloon, this pressure being substantially greater than or equal to the air pressure at the altitude of the balloon. Semi-rigid balloons may have an internal and / or external support structure to help support the gondola beneath this support structure.

[0054] Rigid type balloons have practically disappeared because of the complexity of the rigid structure and because of the lack of efficiency for small balloons due to the weight of this rigid structure which encloses the balloons.

[0055] The gas lighter than air is, for example, helium, hydrogen or a predetermined mixture of one or both of these gases with air.

[0056] The first and second balloons 10a, 10b may include one or more balloons inside each of these balloons, and adapted to be inflated or deflated with air to modify the volume and / or pressure of the balloons 10a, 10b, which makes it possible to control the attitude of the aerostat (its angles of incidence and yaw) and its altitude rise.

[0057] The connecting structure 30 has the function of holding the balloons relative to each other. For example, in the case of the two balloons 10a, 10b shown in Figures 1 to 3, this connecting structure 30 holds the balloons in all directions X, Y and Z, and prevents any movement of these balloons relative to each other, for example under the action of external forces, in particular aerodynamic forces due to the advance of the aerostat or meteorological conditions (such as wind) or under the action of internal forces of the aerostat, such as propulsion forces of varying amplitude and / or directions.

[0058] This connecting structure 30 also has the function of stiffening the balloons themselves and limiting their deformation, by the action of these same external forces.

[0059] The linkage structure 30 of the aerostat 100 according to this disclosure comprises:

[0060] - for each of the first and second balloons 10a, 10b, a first frame 31a of the first ball 10a and a first frame 31b of the second ball 10b respectively, and

[0061] - a first cross member 32 which connects the first frame 31a of the first balloon 10a and the first frame 31b of the second balloon 10b in the lateral direction Y, said first cross member 32 fixing the position of the first and second balloons at least in the lateral direction Y.

[0062] Each of the first armatures 31a, 31b is connected to a balloon of said first and second balloons 10a, 10b, respectively; In other words, the first armature of the first balloon has reference 31a, and the first armature of the second balloon has reference 31b.

[0063] Each of the first armatures 31a, 31b has substantially the shape of the envelope in a transverse plane YZ of said balloon to which the first armature is connected, and this first armature partially surrounds the envelope of the balloon concerned from the outside.

[0064] The first reinforcements 31a, 31b generally have the same length along each balloon, and are preferably symmetrical with respect to a longitudinal plane XZ.

[0065] The first armatures 31a, 31b are positioned in a first longitudinal position xl in the longitudinal direction X.

[0066] The first reinforcements 31a, 31b and the first cross member 32 are rigid elements, that is to say, much more rigid than the gas-filled balloons 10a, 10b, and adapted to withstand mechanical compressive or tensile stresses. They are, for example, made primarily of a steel-type material or composite or composite fibers (carbon fibers).

[0067] The aerostat 100 optionally comprises, as shown in the figures:

[0068] - for each of the first and second balloons 10a, 10b, a second frame 36a of the first 10a ball and a second 36b frame of the second 10b ball respectively, and

[0069] - a second cross member 37 which connects the second frame 36a of the first balloon 10a and the second frame 36b of the second balloon 10b in the lateral direction Y, said second cross member 37 fixing the position of the first and second balloons at least in the lateral direction Y.

[0070] These second armatures 36a, 36b are also connected to a balloon of said first and second balloons 10a, 10b, respectively; In other words, the second armature of the first balloon has reference 36a, and the second armature of the second balloon has reference 36b.

[0071] These second armatures 36a, 36b may have identical or different shapes from the first armatures 31a, 31b. In particular, they have substantially the shape of the envelope in a transverse plane YZ of said balloon to which the second frame is connected, and this second frame partially surrounds the envelope of the balloon concerned from the outside.

[0072] The first reinforcements 31a, 31b also generally have the same length along each balloon, and are preferably symmetrical with respect to the longitudinal plane XZ.

[0073] In addition, the second reinforcements 36a, 36b may have a different length from the length of the first reinforcements 31a, 31b around the balloon envelopes.

[0074] The second reinforcements 36a, 36b are positioned in a second longitudinal position x2 in the longitudinal direction X ([Fig.3]).

[0075] The second reinforcements 36a, 36b and the second cross member 37 are also rigid elements, that is to say, much more rigid than the gas-filled balloons 10a, 10b, and adapted to withstand mechanical compressive or tensile stresses. They are, for example, made primarily of a steel-type material or composite or composite fibers (carbon fibers).

[0076] Fig. 4 presents a front view of a connecting structure 30 of the type of figures 1 to 3 of the aerostat 100, allowing to better illustrate the shape of this connecting structure 30.

[0077] The first frames 31a, 31b, for example, have a shape that can be defined as a C-shape, a portion of a circle, or a portion of an arch. The first frame 31a is connected to the first balloon 10a, and the first frame 31b is connected to the second balloon. The first frames 31a and 31b are oriented in opposite directions, and an opening Oa, Ob of each first frame is oriented outwards from the aerostat 100 (relative to the center of the aerostat between the two balloons). The openings Oa, Ob of the first frames are then suitable for receiving the first balloon 10a and the second balloon 10b, respectively. A body Ca, Cb of each first frame is oriented towards the interior of the aerostat 100, the bodies Ca, Cb of the first frames being connected by the first cross member 32.

[0078] Each of the first reinforcements 31a, 31b has substantially the shape of the balloon's envelope to which it is connected in a transverse plane YZ. The envelope is, for example, inflated under pressure so as to make contact over at least a portion of the length of the reinforcement 31a, 31b attached to said balloon. This contact is, for example, linear or surface contact over a majority or total portion of the length of the first reinforcement 31a, 31b (curvilinear length of the C-shaped form). Thus, the balloon is held in compression within the first reinforcement, which is much more rigid than the balloon under pressure.

[0079] The balloons 10a, 10b are thus held firmly in the first frame 31a, 31b. The balloons 10a, 10b are thus stiffened by the first frames 31a, 31b of the connecting structure 30: they are better able to maintain a general shape, not not only in a cross-section of plane YZ, but also in a cross-section of plane XZ or XY.

[0080] The first C-shaped reinforcements 31a, 31b extend along an angular sector Sc ([Fig.2]) between 20 degrees and 270 degrees around the envelope of each balloon.

[0081] This angular sector Sc is preferably between 90 degrees and 220 degrees to better hold the balloons 10a, 10b by surrounding the envelopes of these balloons.

[0082] The angular sector Sc of a first frame 31a, 31b can extend over a first length along the upper portion lOas, lObs of each balloon and a second length along the lower portion lOai, lObi. As illustrated in [Fig. 2], the angular sector Sc can extend primarily over the upper portion of a balloon. In this way, the balloon 10a, 10b is held securely on its upper portion, which absorbs a static lift force Fl generated by the lighter-than-air gas. This static lift force Fl corresponds to the Archimedes' thrust directed vertically Z, upwards. Thus, the balloon 10a, 10b is supported in the vertical direction Z, upwards.

[0083] In particular, the apex Sa, Sb of each balloon can advantageously be covered by the first reinforcements 31a, 31b. In other words, each first reinforcement extends at least to the apex Sa, Sb of each balloon. In this way, each balloon 10a, 10b is well supported on its upper portion lOas, lObs, which receives a static lift force FL. Thus, each balloon 10a, 10b is supported in the vertical direction Z upwards.

[0084] Each of the first reinforcements 31a, 31b is fixedly attached to a balloon 10a, 10b at a plurality of attachment points Fx1, Fx2, Fx3 ([Fig. 4]), more than two, along the envelope of one of the balloons 10a, 10b, to distribute a fastening stress of the first reinforcement onto the envelope of that balloon. Thanks to this arrangement, the fastening stress at each attachment point can be less than a fastening strength limit, this fastening strength limit being a function of the nature of the balloon envelope and the gas pressure in the balloon. For example, this plurality of attachment points makes it possible to achieve a fastening stress lower than the elastic limit of the envelope of the balloons 10a, 10b in order to obtain effective fastening at each attachment point and to prevent any tearing of the envelope under operating conditions. This elastic limit of the envelope is, for example, between 50 MPa and 110 MPa.

[0085] The plurality of attachment points Fxl, Fx2, Fx3 is in a number, for example, greater than or equal to 3 and less than or equal to 5. This number of attachment points corresponds to a good design compromise for the balloon envelopes used.

[0086] Furthermore, each attachment point Fxl, Fx2, Fx3 may include a first-reinforcement or second-reinforcement fastener At inserted between the balloon casing and an outer fastening layer that encapsulates said fastener. The outer layer is attached to the casing by a process of gluing, sewing, plastic welding, or a combination of these processes. The fastener At is attached to the first or second reinforcement, for example, by a mechanical means, such as a screw, bolt, or cotter pin, or any other means.

[0087] The second armatures 36a, 36b advantageously have similar or identical shapes to the first armatures 31a, 31b and according to embodiments and variants which may be similar or identical.

[0088] According to variants of the connection structure 30 of the aerostat 100, the characteristics of which are shown in [Fig.2], this connection structure 30 may further comprise:

[0089] - a first lower rod 33a directly or indirectly connecting a point lower Pia of the first frame 31a of the first ball 10a and the first crossbeam 32, and

[0090] - a second lower rod 33b directly or indirectly connecting a point lower Pib of the first frame 31b of the second ball 10b and the first cross member 32.

[0091] By "direct or indirect connection," it is understood that each rod can be directly connected to the first cross member 32 or indirectly by another structure itself connected to the first cross member 32, such as a gondola 50, as shown in the figures. These rods 33a, 33b are substantially linear elements, extending between two points to connect them mechanically.

[0092] The rods 33a, 33b are, for example, rigid bars, adapted to withstand mechanical compressive or tensile stresses. They are, for example, made primarily of a steel-type material or composite or composite fibers (carbon fibers).

[0093] These rods are possibly cables adapted to withstand only tensile stresses. They are, for example, mainly made of steel wires or synthetic material wires.

[0094] The first lower rod 33a and the second lower rod 33b are rigid, elastic, or elastic with damping. These rods may be extendable and equipped with extension stops, and optionally equipped with a damper.

[0095] The first lower rod 33a and the second lower rod 33b serve to stiffen the connecting structure 30 of the aerostat. In particular, such rods, positioned in the lower portion of each balloon, act in tension under the action of a static lift force Fl generated by the Archimedes' principle. gas in the balloons, which corresponds to a main force for the linking structure 30.

[0096] According to variants of the linkage structure 30 of the aerostat 100, the linkage structure 30 may comprise:

[0097] - a first upper rod 34a directly or indirectly connecting a point upper Psa of the first frame 31a of the first ball 10a and the first cross member 32, and

[0098] - a second upper rod 34b directly or indirectly connecting a point lower Pib of the first frame 31b of the second ball 10b and the first cross member 32.

[0099] These upper rods 34a, 34b are of the same type as the lower rods 33a, 33b or different.

[0100] These rods are optional because, under the action of the Archimedes' principle of buoyancy from the balloon gas, they function in compression. However, these upper rods improve the rigidity of the connecting structure 30.

[0101] According to variants of the linking structure 30, a linking member 32a, 32b establishes a link between the first armature 31a, 31b and the first cross member 32.

[0102] This connecting element 32a, 32b performs:

[0103] - either a rigid fixed connection so that the first reinforcements 31a, 31b be firmly attached to crossbeam 32,

[0104] - either a joint allowing angular movement between the first reinforcements 31a, 31b and the crossbeam 32.

[0105] The aerostat 100 may further include a tail assembly 40 connecting the first balloon 10a and the second balloon 10b. This tail assembly 40 is, for example, located in a longitudinal tail position xe in the longitudinal direction X, corresponding, for example, to the tail 102 of the aerostat 100. The longitudinal tail position xe is different from the first longitudinal position xl of the first frames 31a, 31b of the connecting structure 30.

[0106] This tail assembly 40 includes a horizontal stabilizer 41 capable of providing an aerodynamic lift component. Preferably, the aerodynamic lift component of this tail assembly 40 is high when the aerostat is moving forward, enabling it to glide like an airplane with wings. The horizontal stabilizer 41 includes an elevator.

[0107] The tail assembly 40 further includes a vertical stabilizer 42 equipped with a rudder.

[0108] Advantageously, the tail assembly 40 of the present aerostat 100 makes it possible to stabilize the aerostat 100, in particular to limit pitching or nose-up movements. In addition, this tail assembly 40 can be capable of generating high lift, thanks to the horizontal stabilizer 41, and for example thanks to the large surface area and possibly the aerodynamic profile of this horizontal stabilizer 41.

[0109] The aerostat 100 advantageously includes a first propulsion device 35, such as one or more propeller engines or jet-type engines (for example, small in size).

[0110] According to one variant, the first propulsion device 35 can be located on the tail assembly 40.

[0111] According to a variant shown in the figures, the first propulsion device 35 is advantageously located on the first cross member 32 of the aerostat 100.

[0112] This first propulsion device 35 is preferably orientable by pivoting about a lateral direction axis Y to be oriented angularly between:

[0113] - a horizontal propulsion position in which the first device of Propulsion 35 is capable of generating a propulsion force in the longitudinal direction X, and

[0114] - a vertical propulsion position in which the first device of propulsion 35 is capable of generating a propulsion force in the vertical direction Z.

[0115] In the vertical propulsion position or in an intermediate position between the horizontal propulsion position and the vertical propulsion position, the first propulsion device 35 is then capable of generating vertical propulsion lift capable of lifting the aerostat 100 in the vertical direction Z upwards.

[0116] The first propulsion device 35 may include two motors as shown in the figures, mounted pivotally on the cross member 32. Each motor is, for example, on either side of the gondola 50, said gondola 50 being located between the two balloons 10a, 10b. The two motors can be oriented independently of each other.

[0117] The aerostat 100 optionally includes a second propulsion device 38 of the same type as the first propulsion device 35, or of a different type.

[0118] This second propulsion device 38 is advantageously arranged on the second cross member 37, particularly in the case where the linking structure 30 of the aerostat includes a second frame 36a, 36b and a second cross member 37 as shown in the figures.

[0119] The second propulsion device 38 can be steerable like the first propulsion device 35, and it can also include two motors, for example located on either side of the nacelle 50.

[0120] Thus, as shown in the figures, the gondola 50 is for example connected at least to the first cross member 32.

[0121] It will be understood that the solution illustrated in the figures, of an aerostat 100 with four steerable engines, provides a propulsion and orientation capacity of a force of very advantageous propulsion, similar to a quadcopter type drone, the two balloons 10a, 10b then providing another Archimedes type lift force thanks to the lighter than air gas in said balloons.

[0122] The aerostat 100 according to this disclosure has other technical features for its operation which we will now describe in detail, these features being very advantageous, in particular to ensure a high degree of safety for its occupant or its transported load.

[0123] We assume here that the aerostat 100 corresponds to the preceding description, and that this aerostat 100 comprises:

[0124] - a first balloon 10a and a second balloon 10b which extend in a direction longitudinal X, each of the balloons consisting of an envelope containing a gas lighter than air,

[0125] - a linking structure 30 configured to hold the first balloon and the second ball in relation to each other.

[0126] The aerostat 100 then further comprises:

[0127] a tail assembly 40 connecting the first balloon and the second balloon in a longitudinal tail assembly position xe in the longitudinal direction X, and

[0128] at least a first propulsion device 35, orientable by pivoting around a lateral direction axis Y to be oriented angularly between a horizontal propulsion position and a vertical propulsion position.

[0129] The aerostat 100 is suspended in the air at an altitude thanks to a total lift St in the upward vertical direction Z, adapted to compensate for or balance the weight P in the downward vertical direction Z. This total lift St for the aerostat in question is the sum of:

[0130] - a static lift Fl generated by the lighter-than-air gas of the first ball 10a and second ball 10b,

[0131] - a vertical propulsion lift F2 corresponding to a component vertical of the propulsion force generated by the first propulsion device 35, and

[0132] - an aerodynamic lift force F3 which is a function of the shape of the aerostat 100 comprising the first balloon 10a, the second balloon 10b and the tail assembly 40, and which is also a function of the angle of incidence of the aerostat 100, and of the speed v of the aerostat 100 in the environment.

[0133] This decomposition of the total lift force St is schematically represented in [Fig. 6], which illustrates such an aerostat 100 in hover. This figure is a longitudinal section in an XZ plane to visualize the gondola 50 between the two balloons 10a, 10b.

[0134] The points of application of these lifting forces have been moved in the XZ plane in order to visualize them, but the weight P or gravitational force of the aerostat 100 is applied to the center of gravity G of the aerostat.

[0135] The static lift Fl corresponds to the Archimedes' thrust directed vertically in the Z direction, upwards. This static lift Fl can be calculated by:

[0136] Fl = Vpg

[0137] where

[0138] V is the volume of gas in the balloons,

[0139] p is the mass density of the air surrounding the aerostat 100 at its altitude, and

[0140] g is the value of gravity (usually g = 9.81 m / s2).

[0141] The weight or gravitational force P is a force directed in the opposite direction to the vertical direction Z, that is to say downwards (towards the ground), and it is equal to:

[0142] P = mg,

[0143] with

[0144] m the total mass of the aerostat 100, and

[0145] g the value of gravity (usually g = 9.81 m / s2).

[0146] The following value is called the effective weight Pe:

[0147] Pe = (m - Vp).g = Ls.g,

[0148] The component (m - Vp) = Ls, often called static heaviness or aerostatic balance ("static heavinees" in English), is the difference between the total mass m of the aerostat 100 and the volume of gas V of the balloons multiplied by the density p of the air surrounding the aerostat at its altitude.

[0149] The total levitation St is then:

[0150] St = Fl+F2+F3

[0151] For a flight at constant altitude, the total lift St must be equal in magnitude (in opposite direction) to the gravitational force P (force equilibrium).

[0152] If the total lift St is less than the gravitational force P, the aerostat 100 is descending.

[0153] If the total lift St is greater than the gravitational force P, the aerostat 100 rises in altitude.

[0154] In other words, the effective weight Pe is compensated by the vertical propulsion lift F2 and / or aerodynamic lift lift F3.

[0155] The aerostat 100 then has the following characteristics:

[0156] 1) the shape of the aerostat is configured so that the aerostat has a fineness Fi greater than 2, which allows it to glide easily,

[0157] 2) the first and second balloons 10a, 10b contain a volume of gas for that the static lift Fl is strictly greater than 50% of the total lift St,

[0158] 3) the first propulsion device 35 is configured so that the lift of vertical propulsion F2 can be strictly greater than 50% of the effective weight Pe of the aerostat 100, in the vertical propulsion position of the first propulsion device 35.

[0159] Thanks to these features, the aerostat 100 has extended high-altitude flight capabilities. In fact, it can ascend to a higher altitude than other aerostats. The aerostat 100 can hover or maintain a constant altitude.

[0160] The static lift Fl and the vertical propulsion lift F2 of the aerostat 100 allow for a stationary flight.

[0161] The static lift Fl and the aerodynamic lift F3 make it possible to ensure flight at a constant altitude.

[0162] In addition, the aerostat 100 is very safe and is capable of maintaining lift even in the event of a major failure or damage.

[0163] If the static lift Fl is lost due to the partial or total loss of gas from the first balloon 10a and / or the second balloon 10b, the aerostat 100 is capable of descending at a low speed to ensure the survival of the occupant or to ensure the integrity of a payload of the aerostat 100. In particular, the first propulsion device 35 is capable of providing vertical propulsion lift F2 to compensate at least partially for the loss of static lift FL. For example, the first propulsion device 35 will move into a vertical propulsion position to provide this compensation.

[0164] If the vertical propulsion lift F2 becomes zero due to loss of power of the first propulsion device 35, the aerostat 100 is capable of gliding downhill to ensure the survival of the occupant or to ensure the integrity of a payload of the aerostat 100. Indeed, the glide ratio Fi of the aerostat 100 and the volume of gas of the first and second balloons 10a, 10b make it possible to ensure this capability.

[0165] The aerodynamic lift-to-drag ratio Fi of an airplane or aerostat is the ratio between the lift Cz and the drag Cx, that is:

[0166] Fi = Cz / Cx.

[0167] In gliding flight without propulsion, the glide ratio Fi also corresponds to the ratio between the horizontal distance traveled Dh and the vertical fall height Hv, or to the ratio between the horizontal speed Vh and the vertical speed Vv (rate of descent), that is to say:

[0168] Fi = Dh / Hv = Vh / Vv.

[0169] The glide ratio Fi of the aerostat 100 is advantageously greater than 2. Thus, the aerostat 100 has a shape configured to obtain this glide ratio. The aerostat 100 is therefore suitable to glide. The glide ratio (Fi) of the aerostat can also be greater than 3 due to its shape, in order to have improved flight capabilities without propulsion.

[0170] The aerostat 100, comprising a first balloon 10a and a second balloon 10b, inherently possesses a fairly high drag compared to an airplane or glider. However, the aerostat 100 can also have a very high lift coefficient (Cl), compensating for this drag to obtain a suitable lift-to-drag ratio.

[0171] The fineness Fi of the aerostat 100 may be less than 10 or less than 7.

[0172] According to one variant, the first and second balloons 10a, 10b contain a volume of total gas so that the static lift Fl is greater than 70% of the total lift St. Thus, the aerostat 100 is safer in case of loss of power of the first propulsion device 35.

[0173] According to one variant, the first propulsion device 35 has a capacity (sufficient power) so that the vertical propulsion lift F2 is greater than 70% or even greater than 100% of the effective weight Pe of the aerostat 100, in the vertical propulsion position of the first propulsion device 35. The aerostat 100 thus develops an improved propulsion lift capacity.

[0174] The aerostat 100 advantageously includes a control unit UC. This control unit is integrated into the aerostat 100 and, for example, into the gondola 50.

[0175] According to one embodiment, the control unit UC detects a loss of gas and measures a descent speed vd of the aerostat 100. The control unit UC can then command the orientation of the first propulsion device 35 with a propulsion angle in the direction of the vertical propulsion position and a power of the first propulsion device 35 sufficient so that the descent speed vd is less than a predetermined first limit descent speed VI.

[0176] The first limiting descent speed V1 is for example less than 10 m / s. Thus, the control unit UC ensures the survival of the occupant of gondola 50 or the integrity of a payload on aerostat 100. Optionally, the initial descent velocity limit V1 is set below 5 m / s or even below 1 m / s to better ensure survival or integrity. This initial descent velocity limit VI can be adjusted in the control unit UC.

[0177] According to one variant, the control unit UC detects the loss of propulsion of the first propulsion device 35 and measures a descent speed vd of the aerostat, the control unit UC can then control the total gas volume of the first and second balloons 10a, 10b and can control the angle of incidence Ai of the aerostat so that the descent speed vd is less than a second predetermined limit descent speed V2.

[0178] The second limiting descent speed V2 is for example less than 10 m / s. Thus, the UC control unit ensures the survival of the occupant of gondola 50 or of

[0179]

[0180] The integrity of the aerostat's payload is crucial. Optionally, the second maximum descent speed (V2) is less than 5 m / s or even less than 1 m / s to better ensure survival or integrity. This second maximum descent speed (V2) can be set in the control unit (CU). According to one variant, the control unit UC detects the loss of propulsion of the first propulsion device 35 and measures a descent speed vd of the aerostat. The control unit UC can then authorize the removal of at least one weighted device from the aerostat 100. For example, the weight device is the first propulsion device 35 or an ancillary device of the first propulsion device 35 such as a fuel tank or batteries or a transported load. Partial nomenclature

[0181] 100 Aerostat 34a First upper rod 101 Nose 34b Second upper rod 102 Tail 35 First propulsion device 10a First balloon 36a Second frame of the first balloon (Oas) Upper portion 36b Second frame of the second balloon (Oai) Lower portion 37 Second cross member 10b Second balloon 37a Connecting element of the first balloon (Obs) Upper portion 37b Connecting element of the second balloon (Obi) Lower portion 38 Second propulsion device 11 Horizontal fin 40 Empennage 12 Vertical fin 41 Horizontal stabilizer 30 Connecting structure 42 Horizontal stabilizer 31a First frame of the first balloon 50 Gondola 31b First frame of the second balloon (Ion) UC Control unit 32 First cross member 32a Connecting element of the first balloon 32b Second linking organ on 33a First lower rod 33b Second lower rod

Claims

Demands

1. Aerostat (100) comprising: - a first balloon (10a) and a second balloon (10b) extending in a longitudinal direction (X), each balloon being made of an envelope containing a gas lighter than air, - a connecting structure (30) configured to maintain the first balloon and the second balloon relative to each other, the aerostat being characterized in that the connecting structure (30) comprises: for each of the first and second balloons, a first frame (31a, 31b) connected to a balloon of said first and second balloons, each of the first frames (31a, 31b) having substantially the shape of the envelope in a transverse plane (YZ) of said balloon to which the first frame is connected, and partially surrounding this envelope externally, said first frames being positioned in a first longitudinal position (xl) in the longitudinal direction (X),and - a first cross member (32) which connects the first frame of the first ball and the first frame of the second ball in the lateral direction (Y), said first cross member (32) fixing the position of the balls in the lateral direction (Y).

2. Aerostat according to claim 1, wherein the first frames (31a, 31b) have a C shape, the first frame (31a) connected to the first balloon (10a) and the first frame (31b) connected to the second balloon are oriented in opposite directions, an opening (Oa, Ob) of each first frame being oriented towards the outside of the aerostat to accommodate respectively the first and second balloons (10a, 10b), a body (Ca, Cb) of each first frame being oriented towards the inside of the aerostat to be connected by the first cross member (32).

3. Aerostat according to claim 2, wherein the first C-shaped frames (31a, 31b) extend in an angular sector between 20 degrees and 270 degrees around the envelope of each balloon.

4. Aerostat according to any one of claims 1 to 3, wherein an upper end zone (ZS) of each balloon is covered by said first frame in order to support in a vertical direction (Z) upwards said first and second balloons.

5. Aerostat according to any one of claims 1 to 4, wherein each of the first armatures (31a, 31b) is fixedly connected to a balloon (10a, 10b) at a plurality of attachment points (Fxl, Fx2, Fx3), in a number greater than 2, along said balloon, to distribute a fixing stress of the first armature on the envelope of the balloon.

6. Aerostat according to claim 5, wherein the plurality of attachment points is in a number greater than or equal to 3 and less than or equal to

7. J. Aerostat according to claim 5 or 6, wherein each attachment point comprises a first reinforcement attachment inserted between the envelope and an external attachment layer enclosing said attachment, and said external layer being attached to the envelope by a process of gluing, sewing, plastic welding, or a combination of these processes.

8. Aerostat according to any one of claims 1 to 7, wherein the connecting structure (30) further comprises: - a first lower rod (33a) directly or indirectly connecting a lower point (Pia) of the first frame (31a) of the first balloon (10a) and the first cross member (32), and - a second lower rod (33a) directly or indirectly connecting a lower point (Pib) of the first frame (31b) of the second balloon (10b) and the first cross member (32).

9. Aerostat according to claim 8, wherein the first lower rod (33a) and the second lower rod (33b) are rigid, elastic or elastic with damping.

10. Aerostat according to any one of claims 1 to 9, wherein a connecting member (32a, 32b) provides a rigid fixed connection between the first frame (31a, 31b) and the first cross member (32) or a hinged connection between the first frame (31a, 31b) and the first cross member (32).

11. Aerostat according to any one of claims 1 to 10, further comprising an empennage (40) connecting the first balloon and the second balloon in a longitudinal empennage position (xe) in the longitudinal direction (X), said longitudinal empennage position (xe) being different from the first longitudinal position (xl).

12. Aerostat according to any one of claims 1 to 11, wherein the first cross member (32) is equipped with a first propulsion device (35).

13. Aerostat according to claim 12, wherein the first propulsion device (35) is orientable by pivoting about a lateral direction axis (Y) to be oriented angularly between a horizontal propulsion position and a vertical propulsion position.

14. Aerostat according to any one of claims 1 to 13, wherein the connecting structure (30) comprises: for each of the first and second balloons, a second frame (36a, 36b) connected to a balloon of said first and second balloons, each of the second frames (36a, 36b) having substantially the shape of the envelope in a transverse plane (YZ) of said balloon to which said second frame is connected, and partially surrounding this envelope externally, said second frames being positioned in a second longitudinal position (x2) in the longitudinal direction (X), different from the first longitudinal position (x1), and - a second cross member (37) which connects the second frame of the first balloon and the second frame of the second balloon in the lateral direction (Y), said second cross member (37) fixing the position of the balloons in the lateral direction (Y).

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