HYBRID ENVELOPE DIRIGEAT

Abstract

Dirigible aerostat (1) comprising an envelope (2) delimiting an interior space (3) of variable volume capable of being filled by a lifting gas, a gondola carrying at least one propulsion unit, a system (6) for varying the volume by clamping, comprising a plurality of sail adjustment cables (7). FIGURE 3

Description

Title of the invention: HYBRID ENVELOPE AIRSHIP

[0001] Technical field

[0002] The present invention relates to a dirigible aerostat. It relates more particularly to a dirigible aerostat comprising an envelope delimiting an interior space with variable geometry capable of being filled with a carrier gas, a nacelle carrying at least one propellant and a system for varying the volume by clamping. Prior art

[0003] A hybrid airship uses both the lift of a lighter-than-air gas, like a balloon, and the aerodynamic lift of its speed of movement in the air, like an airplane. Aerostatic lift, also called Archimedes' thrust, is exerted at the center of aerostatic lift, and aerodynamic lift at the focus of the wing. These two lifts are supposed to compensate for the weight of the machine, which is exerted at the center of gravity. Obviously, aerodynamic lift varies according to speed. It is zero when stationary.

[0004] As an illustration, in a roughly cylindrical airship of the "Zeppelin" type, the Archimedes thrust is in the middle of the length and the focus is about 25% of the length. Whatever the position of the center of gravity, a priori fixed during flight, it will be necessary to compensate for a couple due to the imbalance of moments. This is done by means of an elevator which must be increasingly nose-down as the speed increases. Obviously this increases the drag. The greater the share of aerodynamic lift, the more difficult the problem is to solve, because it is necessary that, in any case, at a standstill, when the aerodynamic lift is zero and the empennage is ineffective, the center of gravity passes through the center of static thrust. Possibly a landing gear or a mast can counter a slight imbalance on the ground.

[0005] The problem is particularly important on hybrid airships. The solution generally adopted consists of placing a balloon at the front and one at the rear. It is thus possible to make the front or rear of the machine heavier by inflating the chosen balloon. But we know that the balloon technique has the disadvantage of increasing the volume of the hull and therefore its wind resistance and its weight.

[0006] To overcome these various drawbacks, the invention provides various technical means. Summary of the invention

[0007] First of all, as a first objective, the invention consists in providing an aerostat di rigable with variable geometry envelope to improve the aerodynamic characteristics of the aircraft.

[0008] Another objective of the invention is to propose a dirigible aerostat with a variable geometry envelope allowing reliable, safe use for all flight configurations of the device.

[0009] To do this, the invention provides a dirigible aerostat comprising an envelope delimiting an interior space and a profile with variable geometry and capable of being filled with a carrier gas, a nacelle carrying at least one propellant, a system for varying the volume by tightening, the volume variation system comprising a plurality of independently controllable wing adjustment cables so as to move the carrier gas along the envelope.

[0010] Advantageously, the variable geometry profile makes it possible to move the aerostatic center of lift CPA along the envelope.

[0011] This architecture allows, thanks to the specific arrangements of the adjustment cables, to vary the volume and the profile of the envelope specifically to allow the carrier gas and therefore the aerostatic center of lift to be moved along the envelope, with the aim of maintaining the aerostat in the best possible balance as a function of the movement of the focus, due to variations in speed.

[0012] Advantageously, the envelope comprises upper and lower longitudinal ribs with which the cables cooperate.

[0013] According to an advantageous embodiment, the dirigible aerostat comprises an automatic pilot allowing piloting in rear centering.

[0014] This arrangement makes it possible to support or supplement the system previously described during the different flight phases of the aerostat.

[0015] Advantageously, the dirigible aerostat comprises a computer adapted to manage the volume of the interior space and the profile of the envelope.

[0016] For this implementation, the computer can for example control the winches of the volume variation system, depending on the positioning requirements of the aerostatic pressure center.

[0017] Depending on the case, the propellant can be electric or thermal. Brief description of the drawings

[0018] All the details of the embodiment are given in the following description, supplemented by figures 1 to 4, presented solely for the purposes of non-limiting examples, and in which: Fig.l

[0019] [Fig.l] [Fig.l] is a schematic representation of an example of a dirigible aerostat according to the invention; Fig.2

[0020] [Fig.2] [Fig.2] shows an example of a multi-lobe envelope capable of being used with a dirigible aerostat according to the invention. Fig. 3

[0021] [Fig.3] [Fig.3] is a cross-sectional view of the envelope when the aerostat moves at very low speed, with zero aerodynamic lift; Fig.4

[0022] [Fig.4] [Fig.4] is a cross-sectional view of the envelope when the aerostat moves at high speed generating high lift. Description of the embodiments

[0023] As illustrated, the dirigible aerostat 1 comprises an envelope 2, preferably flexible, making it possible to form an interior space 3 capable of being filled with a carrier gas. This gas is lighter than the ambient air and makes it possible to generate at least part of the lift of the aircraft.

[0024] In the illustrated embodiment, a nacelle 4 is connected to the envelope 2, for example by links 9. The nacelle serves, among other things, to house the flight systems of the aerostat and at least one thruster 5.

[0025] [Fig.2] illustrates an exemplary embodiment of an envelope 2 of a multi-lobe dirigible aerostat 1 of substantially elongated shape, with a main lobe 10 arranged centrally, and, on each side of the main lobe 10, two lateral lobes 11, cooperating with the central lobe. The neighboring lobes cooperate together so that the interior space is continuous and unique for the five lobes. The dirigible is thus of substantially planar shape. The number of lobes, the shapes and dimensions can vary according to the needs and constraints of use.

[0026] Figures 3 and 4 show that this profile can be more or less uniform, depending on the needs.

[0027] To control the variations in volume and / or profile of the envelope, longitudinal adjustment ribs 12 and 15 are provided, at the level of the lower and upper portions of the envelope.

[0028] At least one upper longitudinal adjustment rib 12, arranged in the upper portion of the envelope, extends longitudinally. In a substantially symmetrical manner, at least one lower longitudinal adjustment rib 15, arranged in the lower portion of the envelope, also extends longitudinally, in vertical alignment with the upper longitudinal rib 12. The upper ribs 12 and lower ribs 15 together form an elongated profile, similar to a wing profile. The longitudinal adjustment ribs 12 and 15 may be made of a metal alloy (aluminum, titanium or other), a composite (preferably fibered), a textile (fabric, fiber, rope or other) or wood, depending on the dimensions involved and the force constraints to be taken into account, and depending on the intended use of the aerostat. To ensure the rigidity of the aerostat envelope, the ribs 12 and 15 have a certain rigidity, while allowing the profile of the envelope to be varied as shown in Figures 3 and 4. This deformability can come either from a certain deformability of the material of the ribs 12 and 15, or by providing a plurality of so-called "flexible" zones, having higher deformability characteristics than the so-called "rigid" zones.

[0029] To maintain, and / or to vary the spacing between the upper 12 and lower 15 ribs, adjustment cables 7 are provided, connected alternately to a plurality of points on each of the ribs, forming a lacing. Each cable has one of its ends fixedly attached to one of the ribs, for example at its position furthest from the central point. The other end of each cable is connected to a tightening module, such as for example a winch 8, provided in the central zone of the assembly. Pulleys 13 arranged along the ribs 12 and 15 allow the cables 7 to move by winding or unwinding along the ribs. In the example of Figures 3 and 4, two cables 7 are provided, one in the front half, the other in the rear half of the envelope. Other arrangements with more cables 7 and more winches and / or other longitudinal positions of the cables and winches can also be used.A high number of independent cables allows for finer adjustment of the volume and envelope profile.

[0030] All these different arrangements are specifically provided to allow the system 6 for varying the volume of the envelope to tension the cables to bring the upper 12 and lower 15 adjustment ribs closer together, or to relax them, to allow the ribs to move apart from each other. The volume variation system 6 is advantageously controlled by the computer 14. One or more cable tension sensors can supplement the control system of the computer 14.

[0031] As illustrated in Figures 3 and 4, the volume variation system is segmented along the length of the envelope to be able to not only vary the overall volume, but also define the profile of the envelope and thus move the aerostatic center of lift CPA, without increasing the overall volume.

[0032] The system consists of two or more lacing units each comprising a winch 8 and a cable 7 and distributed along the length of the ribs and controlled independently so that the carrier gas (hydrogen, helium, or other) can be partially moved along the machine so as to align the overall lift (aerostatic and aerodynamic) with the center of gravity depending on the flight phases.

[0033] Thus, at takeoff, ([Fig.3]) there is no aerodynamic lift, the aerostatic lift is aligned with the center of gravity.

[0034] When taxiing, when accelerating, aerodynamic lift is gradually created at the front of the aircraft. This must be compensated by the elevator in the forward position.

[0035] During the climb, to compensate for the drop in pressure and the pitching effect of the aerodynamic lift, the rear cable(s) will preferably be released, and / or the front cable(s) will be tightened, which amounts to moving the center of aerostatic thrust back ([Fig.4]).

[0036] In cruise flight, the empennages must be neutral.

[0037] During the descent, in anticipation of the deceleration that will occur on the track and which can no longer be countered by the tail, due to lack of speed, the gas is gradually brought forward, which amounts to rolling faster at the rear than at the front. During periods of ascent and descent, the machine is centered rearward and therefore unstable, but an autopilot is able to correct this instability. List of reference signs

[0038] 1. Dirigible aerostat 2. Envelope 3. Interior space of the envelope 4. Nacelle 5. Propellant 6. Envelope volume variation system 7. Adjustment cable 8. Winch 9. Links 10. Main lobe 11. Lateral lobe 12. Upper longitudinal rib for adjusting the envelope 13. Pulleys 14. Calculator 15. Lower longitudinal rib for adjusting the envelope

Claims

Claims

1. Steerable aerostat (1) comprising an envelope (2) delimiting an interior space (3) and a profile with variable geometry and capable of being filled with a carrier gas, a nacelle (4) carrying at least one propellant (5), a system (6) for varying the volume by tightening, characterized in that the system (6) for varying the volume comprises a plurality of independently controllable wing adjustment cables (7) so as to move the carrier gas along the envelope (2).

2. A dirigible aerostat according to claim 1, wherein the variable geometry profile allows the aerostatic center of lift CPA to be moved along the envelope (2).

3. A steerable aerostat according to any one of claims 1 or 2, wherein the envelope (2) comprises upper (12) and lower (15) longitudinal ribs with which the cables (7) cooperate.

4. A dirigible aerostat according to any one of claims 1 to 3, comprising an automatic pilot allowing piloting in rear centering.

5. A dirigible aerostat according to any one of claims 1 to 4, comprising a computer (14) adapted to manage the volume of the interior space (3) and the profile of the envelope (2).

6. A steerable aerostat according to any one of claims 1 to 5, wherein the propellant (7) is electric.

7. A dirigible aerostat according to any one of claims 1 to 5, wherein the propellant (7) is thermal.