Aerostat and manufacturing method thereof

Abstract

An aerostat having an elongate hollow body having a length defining a local axis of the body, the hollow body adapted to receive sufficient lighter than air gas such that the aerostat can become buoyant in air, the aerostat body comprising a series of a plurality of joined body portions, the present invention relates to an elongate hollow body comprising a plurality of body portions, each body portion comprising an outer skin and a hollow interior space wherein a joint is substantially perpendicular to a local axis of the body, the joined body portions comprising two end body portions and a plurality of interior body portions such that the joined body portions together form the elongate hollow body; and a method of manufacturing an aerostat according to any of the preceding claims, the method comprising the steps of: supporting a first body portion to form a first mounted hollow body portion; supporting the second body portion to form a second mounted hollow body portion; contacting the first mounted body portion and the second mounted body portion such that the outer skins of the first body portion and the second body portion are aligned; the outer skin of the first body part and the outer skin of the second body part are jointed together; the process is then repeated with a further body portion, thereby creating an aerostat having an elongate hollow body.

Description

Technical Field

[0001] The present invention relates to an airship having an elongated hollow body having a length defining a local axis of the body; and to a method of manufacturing the same. Background Technology

[0002] Low-latency access to mobile communications and general information services is becoming increasingly critical for economic and social well-being. The Covid-19 pandemic has accelerated this process. New applications (e.g., autonomous driving, telemedicine support) and, more generally, the metaverse requires reliable, low-latency, and high-bandwidth mobile communications.

[0003] Compared to satellites, aerostat-supported platforms have several advantages, primarily because the distance from the transmitter to the receiver on Earth can be much shorter, whereas geostationary satellites are typically at an altitude of 36,000 km, and for “low Earth orbit” (LEO) satellites, it is about 1,000 km.

[0004] The relative proximity of the tethered aerostat platform allows for much stronger signal relay to Earth, avoids the costs of rocket launches, provides shorter development time, and enables power and return connections via tether.

[0005] Recently developed lightweight, high-capacity phased array antennas have the potential to revolutionize global mobile and fixed-line connectivity, for example, by providing cellular phone services, including links to the internet. This depends on their proper positioning, typically between 200 m and 2500 m above most geographic areas. Therefore, suitable tethered aerostats are needed to support these antennas, which must be reliable at medium altitudes in all weather conditions, with power and fiber optic cables, lighting, and lightning protection as part of the tether. These aerostats need to be located below commercial air traffic but must be high enough to provide links up to 80 km in low-population-density areas, up to 30 km in medium-density rural areas, and up to 5 km in urban areas.

[0006] Similarly, there exists a range of Earth observation, meteorological data collection, and astronomical data collection systems that can significantly benefit from the support of suitable tethered aerostat systems that are reliable in all weather conditions, typically at altitudes between 200 m and 22,000 m.

[0007] Tethered aerostats have the potential to be significantly cheaper than satellite systems with similar or improved functionality: power supply and fiber optic cable links can be supported by the aerostat tether or as an integral part of the tether, thus avoiding the expensive and limited return and power systems required by satellites or spacecraft. Furthermore, data latency is critical for many applications, including but not limited to augmented reality, autonomous driving, healthcare, interactive video games, video conferencing, and remote control of UAVs; latency provided by satellites, even low Earth orbit satellites, presents significant problems.

[0008] The need for improved mobile connectivity has spurred a renewed interest in alternative transmission technologies, rather than relying on large numbers of mobile communication masts, such as low-Earth orbit satellites, stratospheric platforms, and tethered aerostats. All of these solutions have problems: data capacity and latency, technology readiness levels, and wind stability.

[0009] Current tethered aerostat systems include tethered rigid airships and non-rigid airships (airships), as well as hybrid balloon / kite systems. Airship-type systems are typically designed to tilt relative to the horizontal to provide both aerodynamic lift and buoyancy. Hybrid balloon / kite systems work by having a balloon provide lift in low winds and a kite in high winds. Hybrid balloon / kite systems are generally less expensive than airships. However, for these balloon / kite systems operating in high winds, the horizontal drag on the balloon is high, and therefore the kite needs to be large, resulting in considerable drag to provide sufficient lift to maintain altitude. This large drag necessitates a very strong and therefore heavy tether with its own associated drag, requiring a larger balloon / kite system to support it, thus reducing payload capacity.

[0010] Current tethered airship designs and balloon / kite systems cannot withstand winds exceeding 50 knots for smaller systems, and even for very large systems, winds exceeding 70 knots or an extreme 100 knots. For continuous operation at usable altitudes typically exceeding 400 m, high wind speeds exceeding 100 knots must be maintained. In strong winds, existing systems become unstable and move uncontrollably, eventually being blown away.

[0011] Due to these factors, it has been impossible to design and build a reliable tethered aerostat system to provide high availability service to date, as very high wind conditions are encountered almost everywhere, especially at the appropriate altitudes required for many different applications. This, in turn, means that any potential use of tethered kites / balloons carrying systems requiring high availability and reliability is impossible.

[0012] Systems lighter than air balloon / kite systems are described by example in US 2011 / 0222077A1, US 2,398,745 and US 2,431,938 granted to Jalbert, US 4,029,273 granted to Cristolfel Jr., US 6,016,998 granted to R. Allsopp, and US Patent No. 6,499,695 granted to Talamo. A combined buoyancy wing for wind power generation or aerial advertising is described in US 6,555,932 granted to Mizzi. These combined balloon / kite systems are also commercially available for surveillance and advertising purposes, such as the SkyDoc™ Aerostat supplied by Floatograph Technologies LLC of SilverSpring Md., Maryland, or the Helikite kite supplied by Allsopp Helikites Ltd of Fordingbridge, Hampshire, UK. These systems have been used for both military and civilian purposes, and the data generated has been described as being transmitted to and from ground stations via wireless, cable, or fiber optic connections.

[0013] US 2018 / 0050797 A1 discloses a conceptual tethered, lighter-than-air unmanned aerial vehicle with wings and a fuselage. However, it does not address how to maintain this arrangement to ensure its stability in the atmosphere. KR 10-2016-0081328 discloses a buoyant aerostat tethered to the ground level. However, it does not address how to stabilize this device in the atmosphere. US 2016 / 0122014 A1 discloses a conventional airship attached to the ground by two tethers. US 3,620,292 discloses a winged balloon of a known type.

[0014] An airship system is highly stable under extreme weather conditions, suitable for various locations, and can withstand meteorological challenges including extreme gusts and lightning strikes. It can prevent snow and ice accumulation and has safety features to prevent accidents with low-flying aircraft. Therefore, it may be valuable in a variety of applications (including but not limited to the above-mentioned applications).

[0015] However, these aerostats must be large enough to provide the buoyancy required to lift a suitable payload. Furthermore, significant buoyancy is needed to support the tether, which must contain a lighting conductor necessary for all-weather operation at suitable altitudes (above 200 m, preferably 1000 m, and most preferably 1500 m). A typical required aerostat volume is at least 300 m³. 3 More preferably, above 1000 m 3 International patent application number PCT / GB2022 / 053290 provides an example of a vertical buoyancy airfoil.

[0016] Conventionally, large airships are transported uninflated and folded. However, if the foldable materials currently used are to be appropriately lightweight and strong, they suffer from significant helium permeability, and these airships typically need to be refilled with helium every two to six weeks by snagging them down to the ground or by some other means. This is highly undesirable, as the launch and recovery of large airships are significant tasks requiring suitable weather conditions (moderate gusts) and careful management. The time spent also results in significant disruptions to communication services.

[0017] Therefore, airship skin is required where the strength-to-weight ratio is as high as possible and where the skin prevents significant helium or hydrogen permeation.

[0018] These skin properties are also required for cryogenic tanks for liquid hydrogen and liquid helium used in aircraft or drones, which also require light weight, high strength and low permeability, but add the requirement to withstand (preferably repeatedly) cooling to the relevant cryogenic temperature (typically between a few Kelvin and tens of Kelvin).

[0019] It is well known that the diffusion rate of helium or hydrogen through metals is generally much lower than that through plastics, and numerous attempts have been made to combine fiber-reinforced plastic components with thin skins or foils of metals, particularly aluminum, gold, etc. Typically, fiber-reinforced skins are made from woven resin “prepregs,” composites made of “pre-impregnated” fibers and a partially cured polymer matrix, such as epoxy or phenolic resins. These woven “prepregs” have been placed near aluminum foil films, and the systems are often cured in autoclaves. These systems are highly disappointing; small defects (even as small as a few microns in diameter) in the aluminum foil or its joints allow helium or hydrogen to pass through, and the resin and woven prepregs are not sufficient barriers to achieve significantly lower diffusion paths for helium or hydrogen compared to existing aluminized plastic systems.

[0020] Fiber composite materials with suitable metal barrier and bonding technologies for airship skins would allow airships to operate for much longer periods without helium replenishment. Furthermore, if these airship skins can be implemented, they have the potential to last for many years, provided the external metal skin blocks UV weathering. However, such airships would be large and deployable, posing significant challenges to manufacturing and transportation. Summary of the Invention

[0021] In a first aspect, the present invention relates to an airship having an elongated hollow body having a length defining a local axis of the body, the hollow body being adapted to receive a gas lighter than air such that the airship can become buoyant in air, the airship body comprising a series of multiple joined body portions, each body portion comprising an outer skin and a hollow internal space, wherein the joints are substantially perpendicular to the local axis of the body, the joined body portions comprising two end body portions and multiple internal body portions such that the joined body portions together form the elongated hollow body.

[0022] "Buoyancy in the air" means that the airship is lighter than the air, for example, the buoyancy is greater than the weight of the airship.

[0023] "Local axis of the body" refers to the line connecting the adjacent centroids of the cross section of the body.

[0024] Preferably, the hollow, joined body portion includes an outer skin comprising a metal foil layer sandwiching a first unidirectional fiber layer embedded in a cured resin matrix and a second unidirectional fiber layer embedded in a cured resin matrix, wherein the second unidirectional fiber layer is oriented at an angle to the first unidirectional fiber layer. Preferably, the metal foil is the outermost layer of the outer skin.

[0025] It has been found that having metal foil on the outer surface of the airship skin provides several significant benefits:

[0026] (a) Metal foil, particularly aluminum foil, has high reflectivity. This high reflectivity reduces the impact of solar radiation on the airship's temperature. Diurnal variations in airship temperature can lead to significant pressure changes within the airship, resulting in helium loss or increased enclosure design pressure in constant-volume airship systems. Compared to conventional plastics, airships with reflective metal foil (such as aluminum foil) as the outermost layer can reduce diurnal temperature variations by one-half to three-quarters.

[0027] (b) Metal foils, particularly aluminum, have robust atmospheric lifetimes and are especially insensitive to degradation caused by moisture and UV radiation. Conventional airship skins typically have operational lifetimes measured in months. Aluminum foils have lifetimes measured in decades or longer.

[0028] This arrangement has been found to achieve a rigid outer skin that is highly impermeable to hydrogen and / or helium while also having relatively low weight. The use of unidirectional fibers allows for a high fiber-to-resin content, which gives a high strength-to-weight ratio.

[0029] Preferably, the outer skin comprises an outermost metal foil layer and an innermost metal foil layer, thereby sandwiching two unidirectional fiber layers embedded in the cured resin matrix between them.

[0030] For the manufacture of containers from skin panels, a joining system is required to properly join the body portions. It has been found that by having skin elements on one or both sides of the butt joint, with a butt joint, it is possible to manufacture joints that provide minimal hydrogen and / or helium leakage and are extremely robust, without significantly increasing the weight of the skin. Therefore, preferably, at least one pair of adjacent body portions are butt-jointed to form a continuous skin region with a joint line therebetween, wherein at least one additional skin panel is positioned to cover both the innermost and / or outermost layers of the joint line.

[0031] This arrangement provides an effective seal against hydrogen and / or helium leakage because the joint is covered by one or two additional skin panels. The main principle of this joint design is that gas diffusion or flow through the joint encounters one or more metal foil surfaces, or must travel longitudinally through another pair of skin panels (rather than through their thickness), which provides a much longer path and therefore a much larger seal.

[0032] Preferably, adjacent skin panels have a joint area adjacent to the joint line, in which no metal foil layer is present. This allows for the formation of a continuous resin seal in the joint area by placing another skin panel, resulting in greater joint strength.

[0033] Preferably, the other pair of skin panels does not have an innermost metal foil layer. This is for similar reasons, to achieve a continuous resin seal in the joint area.

[0034] It has been found that each joint area extends from the joint line by a length that is 5 to 150 times the thickness of the outer skin outside the joint area, thereby providing an effective hydrogen and / or helium seal.

[0035] Alternatively, the joint can be formed as an overlapping joint, wherein at least a pair of adjacent body panels overlap each other to form a continuous outer skin region with an overlapping area, wherein at least one additional skin panel is placed to cover the overlapping area.

[0036] In such an overlapping joint, one or two of the adjacent body sections may have some metal foil removed in the overlapping area adjacent to the joining overlapping panels. At least one additional skin panel covering the joint may not have a continuous metal foil layer in order to allow for better load transfer between one body panel and another.

[0037] This arrangement of the outer skin provides a very effective helium seal, with minimal weight and thickness of the skin. Therefore, preferably, each skin panel has a thickness of 0.1 to 5 mm, more preferably 0.1 to 3 mm, and more preferably 0.2 to 2 mm.

[0038] Preferably, the metal foil is any metal that is malleable and stable in air, such as aluminum or gold, but aluminum is preferred. The metal foil is typically 0.5 to 200 micrometers thick, preferably 5 to 40 micrometers thick, and most preferably 8 to 25 micrometers thick.

[0039] These foils are manufactured by rolling and typically have small holes that provide flow paths through their thickness. It has been found that sealing these holes with resin is desirable but not necessary, and this process occurs naturally if sufficient curing pressure and resin are used. Too much resin is undesirable because, to achieve a high strength-to-weight ratio, a low volume fraction of resin compared to the fiber is preferred, consistent with having extremely low gas porosity in the resin / fiber system.

[0040] Therefore, preferably, the volume of the cured resin matrix is ​​15% to 100% of the volume of the unidirectional fiber, more preferably 30% to 70%, and more preferably 45% to 70%, to provide a good strength-to-weight ratio and good barrier properties.

[0041] The resin can be any suitable thermosetting thermoplastic resin applicable to fiber composites, such as epoxy resin.

[0042] Preferably, the angle between the first unidirectional fiber layer and the second unidirectional fiber layer is at least 10°, preferably at least 25°, more preferably 45° to 90°, which allows the strength of the skin to be customized according to the magnitude of the maximum stress required in different directions.

[0043] Preferably, the unidirectional fiber is carbon fiber or Kevlar. TM Carbon fiber or Kevlar prepreg can be used with a weight of 30 g / m² to 500 g / m².

[0044] The gas porosity e is defined as the fraction of free space in the total volume of the resin / fiber system that can be used for fluid (in this case, helium or hydrogen) flow. Preferably, the cured unidirectional fiber layer embedded in the cured resin matrix has a gas porosity of less than 5 vol%, preferably less than 1%, and most preferably less than 0.1%.

[0045] Another advantage is that multiple internal body parts are essentially identical, meaning they have the same geometry. This simplifies manufacturing.

[0046] Depending on the requirements, the airship may include 5 to 500 internal body sections. Each internal body section may have a dimension of 30 to 4000 cm in the direction perpendicular to the length of the body. For example, if the body sections are cylindrical, they will have a diameter of 30 to 4000 cm.

[0047] The aerostat can be positioned horizontally on the ground in preparation for launch, or it can be buoyantly positioned in the atmosphere at an altitude of 100 m to 10,000 m, more preferably 200 m to 5,000 m, and most preferably 250 m to 3,000 m.

[0048] Preferably, the airship includes a tether that connects the airship to a substantially horizontal position on the ground.

[0049] In use (i.e., when there is buoyancy in the air), the local axis of the body can be oriented substantially horizontally or vertically. If vertically oriented, the length extends in use between the upper and lower ends of the body, which together provide both the upper and lower ends of the body. However, in manufacturing, the local axis is preferably horizontal, although a vertical orientation is also possible.

[0050] Furthermore, it has been found that it is particularly advantageous when the airship is shaped as an airfoil. Therefore, preferably, the elongated body has a horizontal section at each point along substantially the entire length, which is an airfoil, thereby providing a leading edge and a trailing edge, and between them, for each horizontal section, a chord line defining the section between the leading edge and the trailing edge, which has a chord length.

[0051] Optionally, the elongated body can be arranged in a backsweep or frontsweep configuration to provide appropriate mass distribution and stability. Therefore, preferably, the aerostat includes a region oriented at an angle to the vertical direction. A backsweep or frontsweep configuration can be achieved when the front and trailing edges are located within a single vertical plane of symmetry parallel to the wind direction during use in the region oriented at an angle to the vertical direction.

[0052] Low-tow aerostats are highly preferred for operation in high winds, as they do not require excessively strong and therefore heavy tethers. If the aerostat has a high tow, it needs to be larger to support the weight of the heavy tethers and payload in high winds. Larger aerostats are more expensive and less economical. It has been found that a tow factor of less than 0.35, preferably less than 0.2, and more preferably less than 0.06 is needed for practical utility in carrying a substantial payload in winds greater than 30 m / s.

[0053] In this application, the drag coefficient of the tethered aerostat is defined as Where F is the horizontal aerodynamic drag, ρ is the air density, u is the horizontal component of the wind speed, and as is conventional in airfoil theory and well known to those skilled in the art, A is the planar area of ​​the airship when viewed horizontally perpendicular to the wind. The leading edge at any vertical level is defined by the point where it first encounters the oncoming air, and the trailing edge at any level is defined by the point where it last encounters the oncoming air.

[0054] Preferably, the airship has a length of 5 to 500 m.

[0055] In a second aspect, the present invention relates to a method for manufacturing an airship as described herein, the method comprising the steps of: supporting a first body portion to form a first mounted hollow body portion; supporting a second body portion to form a second mounted hollow body portion; contacting the first mounted body portion and the second mounted body portion such that the outer skins of the first body portion and the second body portion are aligned or overlapped; subsequently joining the outer skins of the first body portion and the second body portion together; and subsequently repeating the process with another body portion, thereby producing an airship having an elongated hollow body.

[0056] Therefore, these systems allow the mounted body sections to be raised from the ground and properly positioned, with their weight and shape supported, making it easy to perform the engagement.

[0057] Importantly, the spacing between systems must be controlled to ensure that the outer skins are aligned with an accuracy within three skin thicknesses, preferably within two skin thicknesses, and most preferably within one skin thickness, to guarantee a good joint. If the skins are misaligned, wrinkles or other defects will subsequently lead to poor joint quality and gas containment failure.

[0058] The hollow body portion is preferably manufactured by laying a metal foil and a prepreg, including a unidirectional fiber layer coated with uncured resin, onto a solid forming device that may have a release film, and enclosing it in a vacuum bag before curing at an appropriate resin curing temperature and time, as is well known to those skilled in the art of composite component manufacturing. The forming device may be flat or curved to form elements of the airship surface or canister.

[0059] Each hollow body section can be cured as a single molded article, or cured as smaller parts and assembled accordingly. This makes it easier to cure each hollow body section in an autoclave, which can then reach very high pressures to reduce the porosity to an acceptable level. Curing in the autoclave at pressures up to 8 bar gauge pressure minimizes hydrogen and / or helium permeability.

[0060] During the “layout” or placement process, it is important to lay new layers without wrinkles, inclusions, or air pockets, as is well known to those skilled in the art. If the surface is curved in only one direction, where the minimum principal curvature is zero (see Gauss's Theorema Egregium) and the maximum principal curvature is non-zero, a thin surface can be easily laid. However, if the surface has two non-zero principal curvatures, the surface will wrinkle unless appropriately sized cells are used compared to the minimum principal curvature.

[0061] It has been found that the alignment tolerance should preferably be less than three times the skin thickness, more preferably less than twice the skin thickness, and most preferably less than the skin thickness.

[0062] In a first embodiment of a second aspect of the invention, a first body portion is placed in a first support frame to form a first mounted hollow body portion, and a second body portion is placed in a second support frame to form a second mounted hollow body portion. Such a support system can be an external frame supported on a floor, ceiling, or wall. To achieve good edge alignment and edge quality, the spacing between the support frames must be close enough to provide adequate support, but far enough apart to allow for the placement of joint strips.

[0063] In this embodiment, internal tension straps can be attached to the interior of the outer skin of the first and second body parts, and then additional body parts are joined to the first and second body parts. In this way, the airship is assembled piece by piece, making the interior easily accessible.

[0064] Preferably, each support frame includes at least one support edge parallel to the joint, the support edge contacting the periphery of the outer skin of the mounted body portion near the joint. Thus, the body portion can be seated and securely held in place within the support edge. Preferably, the body portion is initially loosely held by the support edge to allow adjustment of its position before it is tightly secured during engagement.

[0065] In a second alternative embodiment of a second aspect of the invention, a first body portion is positioned around a first support mold portion to form a first mounted hollow body portion, and a second body portion is positioned around a second support mold portion to form a second mounted hollow body portion. In the context of the invention, such a support mold is interchangeably referred to as a mandrel. This approach may involve the mandrel providing an internal support surface for placing the body portions. Such a mandrel may preferably have a center of mass on a local axis. Each support mold portion may be joined together, and may be separate or multiple portions of a larger single mandrel.

[0066] Preferably, a means is provided to provide external pressure using a ring clamp or an external pneumatic tube to apply pressure to the skin joint and the heating arrangement, thereby forming a joint whose axis is perpendicular to a local axis or locally close to the skin surface.

[0067] It has been found that spindle support systems are particularly suitable for manufacturing airship shells with circular axisymmetric cross-sections having a common local axis. Circular cross-sections are preferred because they allow the airship's internal pressure to support the shell skin without requiring internal structures such as tethers to shape the airship shell into a desired non-circular shape.

[0068] Typically, a mandrel system consists of one or more mandrels with a circular cross-section having a common axis. Cylindrical, conical, or tapered mandrels can be used to achieve the desired airship shape.

[0069] Preferably, the support mold or mandrel is adjustable, making it expandable and contractible to provide a variable-size support mold. This mandrel system with an adjustable diameter allows for the formation of body portions adjacent to a series of previously formed body portions by sliding the mandrel within the previously formed body portion, thereby achieving excellent alignment of adjacent body portions.

[0070] Any cylindrical or tubular series of body sections will require tapered closures at both ends of the cylinder or variable diameter tube. This arrangement requires that at least one of the mandrels be constructed in a manner that allows for disassembly and removal via an open end cap that provides sealing pressure control when in place.

[0071] The invention will now be illustrated by way of example with reference to the following figures.

[0072] Figure 1 A plan view and a side cross-sectional view of the airship according to the present invention are shown.

[0073] Figure 2 a and Figure 2 b shows a plan view and a side cross-sectional view of two additional airships according to the present invention.

[0074] Figure 3 a and Figure 3 b shows a plan view and a side cross-sectional view of two additional airships according to the present invention.

[0075] Figure 4 This is a perspective view of the end body portion in a support frame used in the method according to the invention.

[0076] Figure 5 It is for use in the method according to the invention. Figure 4 A perspective view of the end body portion of the support frame, wherein the second support frame is in place.

[0077] Figure 6 a is Figure 5 The three-dimensional view of the arrangement shown indicates that the internal main body is already placed within the second support frame, and Figure 6 b shows the details of the joining process between the body parts.

[0078] Figure 7 yes Figure 6 The diagram shown is a perspective view of the arrangement after the main body is joined, in which several straps have been placed inside the hollow interior space of the main body.

[0079] Figure 8 According to the method of the present invention, after several additional internal body parts have been added and joined together Figure 7 A three-dimensional view of the main body shown.

[0080] Figure 9 This is a perspective view of two completed halves of an airship produced according to the method of the present invention before they are joined together to form the airship.

[0081] Figure 10 It is by... Figure 9 The diagram shows a perspective view of the airship according to the invention, formed by joining the two halves together.

[0082] Figure 11 Several views of an axisymmetric airship shell with a straight local axis, formed by the present invention, are shown. It shows a 3D perspective view with no visible joints on the skin, and also illustrates key body components.

[0083] Figure 12 Several views of another axisymmetric airship formed by the present invention are shown, along with more details regarding possible joint arrangements.

[0084] Figure 13 A three-dimensional end view of the compression mandrel used to form the cylindrical body portion is shown.

[0085] Figure 14It shows the method for forming Figure 13 The cylindrical body portion shown has an uncompressed mandrel with a wedge-shaped section inserted inside.

[0086] Figure 15 Views are shown that depict cylindrical body segments formed on such a mandrel.

[0087] Figure 16 A side view shows the process of forming several cylindrical body segments.

[0088] Figure 17 A three-dimensional view shows the formation of the conical body segment joined to the cylindrical segment.

[0089] Turn to the attached diagram. Figure 1 An airship according to the invention is shown, having an elongated hollow body with a substantially constant airfoil cross-section, and a substantially straight leading edge 108 and a substantially straight trailing edge 109. The airship has two end body portions 101 (the length of the body is defined between these end body portions) and a plurality of substantially identical inner body portions 103 having parallel sides 105 joined together by joints 102 such that the sides 105 and the joints 102 are substantially perpendicular to the length of the body. At the center are two central body portions 104.

[0090] Due to the internal structure that holds the airship skin in place, the airship skin 106 is slightly undulating; however, a smooth exterior is also preferred. Since the internal body portion 103 is identical, the airship has a uniform cross section 107 (shown as cross sections AA and BB) except for the end body portion 101 and to a limited extent in the central wedge section 104.

[0091] The skin of the hollow body is made of an outermost metal foil layer and an innermost metal foil layer (with the metal foil sandwiching the cured resin layer and the fiber layer between them) or alternatively, it is made of one or more metal foils and cured resin and fiber layers.

[0092] Such an aerostat can be filled with hydrogen and / or helium and launched to take a position above the ground in the atmosphere, and can be tethered to a horizontal position on the ground. If such an aerostat is to be deployed for telecommunications purposes, it may include an antenna, such as a phased array antenna.

[0093] Figure 2 a shows a plan view (and a side sectional view) of another airship according to the invention, which is similar to Figure 1 The airship shown has a certain curvature on its leading and trailing edges. Figure 2 a shows an airship 200 with a distinct undulating structure in its skin. Figure 2 b shows the comparison Figure 2 The airship 203 shown in Figure a is essentially the same, but its skin is smooth with minimal undulations. Due to the differences in the internal body sections, sections 201, 202, 204, and 205 vary along the length of the airship. Sections 201 and 204 are referenced to the section at point AA, and sections 202 and 205 are referenced to the section at point BB.

[0094] This system compared to Figure 1 The advantage of the system shown is that, for a given airship region, the aerodynamic drag of the airship can be beneficially reduced. However, manufacturing such a system is expensive, as the variable-sized joints or edges 206 require a complex and costly support system during the manufacturing process. Furthermore, each segment 207 differs slightly from its adjacent segments, thus requiring the skin to be manufactured with non-parallel edges, different skin circumferential lengths, and non-parallel segment edges 206.

[0095] Figure 3 a is a plan view (and side sectional view) of another airship 300 according to the present invention, which has a variable cross-section and curved leading and trailing edges. Figure 3 In section a, the airship 300 has a distinct undulating structure in its skin. Figure 3 b shows the same airship 303, but with minimal undulations in the skin. Sections 301 and 304 are referenced to the section at AA, and sections 302 and 305 are referenced to the section at BB.

[0096] This system compared to Figure 1 or Figure 2 The advantage of the system shown is that, for a smaller horizontal airship size, aerodynamic stability can be improved, which makes transportation easier, but it is compared to Figure 1 and Figure 2 The system shown has another significant drawback in terms of its much greater manufacturing complexity.

[0097] The airship according to the present invention can be manufactured in the following exemplary manner.

[0098] Figure 4 This is a perspective view of the end body portion 500 in the support frame 501 at the start of the manufacturing method according to the invention. The frame 501 includes a support edge 502 and an open mesh structure 503, in which the end body portion 500 is tightly disposed. Once manufacturing is complete, the frame 501 can be disassembled and slid out of the airship.

[0099] The support edge 502 engages tightly with the periphery 504 of the end body portion 500 to an accuracy of less than 1 mm, preferably less than 0.3 mm, causing an area of ​​the end body portion 500 to protrude beyond the plane of the frame 501. This is to allow for the formation of a joint along the edge 504, as will be described. Depending on the detailed design of the edge of the end body portion, the end body portion 500 protrudes from the frame 501 by approximately 10 mm to 50 mm.

[0100] like Figure 5 As shown, the next step in this process is to place the second support frame 600 (which includes two rectangular frame portions 601, 602) adjacent to the first support frame 501. The second support frame 600 includes two support edges 603, 604 to receive the internal body portion, such as... Figure 6 As shown.

[0101] exist Figure 6 In the middle, the end body portion 500 is held in place by a support edge 502 attached to the frame 501 and thus in contact with the second support frame 600. An inner body portion 704, made of a cured composite material of fibers and resin (in this case, several portions 706 joined at joint 705), is placed within the two support edges 603, 604. The inner body portion 704 is a continuous, smooth strip with a minimum principal curvature approaching zero at any point on the strip surface, and has a constant cross-section and a constant width in a plane parallel to the axis (shown as AA in this case).

[0102] The mating joint is shown, wherein additional skin panels 708, 707 are placed on the inner and outer sides to cover the mating line of the mating joint (see [reference]). Figure 6 b and Figure 6 c). The spacing between frames 501 and 601, 602 is controlled such that the skins of the inner body portion 704 and the end body portion 500 are aligned with each other to an accuracy within three skin thicknesses, preferably within two skin thicknesses, and most preferably within one skin thickness, to ensure a good joint. It is understood that for large airships with chord lengths exceeding 10 m, achieving skin alignment accuracy within one skin thickness, where the skin thickness can be less than 0.5 mm, presents a challenge.

[0103] If the skin is misaligned, wrinkles or other defects will subsequently lead to poor joint quality and gas containment failure. To achieve good skin alignment and joint quality, the spacing between the support edges 502 and 603 must be close enough to provide adequate support, but far enough apart to allow for the placement of additional skin panels 707 and 708.

[0104] Appropriate attachment means for skins 704 and 700 should allow for initial placement, wherein movement of the skin relative to its supports or sliders can be arranged, followed by means to reduce sliding to a negligible level. This can be achieved by vacuuming between the frame and the sheet surface, by magnetic attachment, or by using tape or adhesive that can be removed later in the process.

[0105] Once the joint is completed, an internal "curtain" 801 of tension straps is introduced into the hollow internal space between the opposite sides of the skin of the main body section, as shown in the image. Figure 7 As shown. The curtain 801 is typically attached to the inner surface of the skin with a line parallel to the airship's axis AA and perpendicular to the airship's long chord to provide control over the skin's shape under pressure during airship operation. A relatively thin section 802 allows access for insertion of the curtain through the opening side of 800.

[0106] The additional support frame and the internal body parts can then come into contact and engage to produce... Figure 8 The arrangement shown represents almost half of the completed airship. The partially completed airship skin assembly 900 is supported on several frames 901, with several joints 902 regularly spaced apart.

[0107] Figure 9 The diagram shows two halves of the airship 1000 and 1001 (of different lengths in this case, but they may be similar) supported on frame 1002 immediately preceding the final joint of edges 1003 and 1004. The final joint has additional inward protrusions (such as small flanges) that allow for a good joint to be formed without internal contact. The flanges provide additional stiffness to the surface, allowing the outer skin to be pressed against the surface, and the joint is sealed by thermosetting or by gluing. Additional strength can be obtained by gluing the flanges together.

[0108] Figure 10 The final airship skin or shell assembly is shown, and all that remains is to remove the final support frame. The resulting airship is then suitable for filling with hydrogen and / or helium to make it buoyant in the air, allowing it to be positioned in the atmosphere at an above-ground location, with the upper end positioned substantially vertically above the lower end, and preferably with an attached tether connecting the airship to a substantially ground-level position.

[0109] Figure 11 Details of an axisymmetric airship shell 1100 with a straight local axis 1116, formed by the present invention, are shown. Figure 11 a shows a cross-sectional view of the cover skin made by the present invention, without detailing the individual skin joints.

[0110] Figure 11 b shows a side elevation view of the axisymmetric airship, detailing the transition body sections 1110 and 1112 ( Figure 11 The shape of (not shown in b) and the position of the tail 1102 for airship stability, as well as the positions of the winglets 1106 (if required) and the payload attachment 1105. Figure 11 c shows a 3D exploded view of the axisymmetric airship skin 1100. The tail section 1102 is preferably manufactured as a separate pressurized hollow container according to the invention.

[0111] The essence of this airship shape is its shape-volume, and therefore the majority of its buoyancy is provided by the central cylindrical section 1101 (composed of a cylindrical body portion) and the end conical body portions 1109 and 1114, all of which have surfaces curved in only one direction, thus having a minimum principal curvature of zero and a maximum principal curvature of non-zero, and can be formed from flat skin sheets. These are examples of shapes in which thin surfaces can be easily laid out and are more easily manufactured by the method of the present invention than the continuously variable cross-sections of conventional airships. However, to achieve the low drag coefficient desired in high-performance airships, suitable transition body portions are manufactured to ensure minimal boundary layer separation when the external wind direction is substantially parallel to the straight local axis. In this example, this is achieved by the transition body portion being part of spherical surfaces 1103, 1104, as... Figure 11 The side elevation view of b is shown. For low-floating airship towing, the transition body portion may also have an elliptical shape, or one axis of the ellipse may be along a local axis of the asymmetric body 1116, which is substantially parallel to the external airflow direction 1117.

[0112] exist Figure 11 In step c, the body portion through which the external wind passes is successively formed by a nose cap 1108, manufactured as a single small element in a suitable mold. This nose cap, according to the invention, is joined to a conical end body portion 1109, made of a flat skin element that is appropriately cut and joined and bent along a main axis. This conical end body portion is further joined to a front transition section 1110, made of cast sheet 1111. A cylindrical body portion 1101 is formed, which is then joined to a rear transition body portion made of curved sheet 1113. This rear transition section is joined to a rear conical body portion 1114, which is joined to a small rear end cap 1115. The conical sections may have several included angles; for example, the body section between the front end cap 1108 and the transition section 1110 may be assembled from several cones, with the transition section in between, to allow for a better approximation of a spherical nose profile. This spherical nose profile allows for better airship towing performance.

[0113] Figure 12 A 3D example and plan view 1201, a front elevation view 1202, and a rear elevation view 1203 of such an airship skin 1200 are shown, along with one of several frames 1204 used in manufacturing. Individual cylindrical body sections 1205 and overlapping joints 1206 of these body sections are shown, where relatively narrow skin strips provide strength and a penetration barrier. Overlapping joints in transition body sections 1207 and conical body sections 1208 are shown.

[0114] Figure 13 A mandrel is shown serving as a support mold for forming a cylindrical body portion. 1300 is a 3D view, and 1301 is a view along a local axis 1302. The mandrel is mounted on a guide rail 1303 parallel to the local axis. The mandrel surface 1304 on which the skin element is laid and formed is expandable and contractible to provide a variable-size support mold, shown here with an opening slot 1306 into which a movable wedge can be inserted, thereby allowing the outer surface of the mandrel to become a complete cylinder on which the skin can be formed. When the wedge is withdrawn, the mandrel surface can relax or contract and disengage from close contact with the previously formed skin surface. This lack of close contact allows the mandrel surface to move along the local axis without inducing significant shear forces on the skin surface.

[0115] Figure 14 It shows the relationship with Figure 13 A similar view, but with wedge-shaped sections inserted.

[0116] Figure 15The cylindrical body section formed on such a mandrel is shown. 1501, 1503, 1505, and 1507 are cross-sections through the mandrel (and, where appropriate, the skin), and correspond to 3D views 1500, 1502, 1504, and 1506, respectively. 1500 and 1501 show the mandrel in a contracted form, and 1502 and 1503 show the same mandrel in an expanded form, ready to receive the skin elements. The following figures 1504 / 1505 show the placement of the body portion 1508. The body portion will preferably be manufactured in a flat form with layers of foil and fiber-reinforced composite material, as previously described. The length of the body portion (which can be manufactured by assembling and joining several elements on a flat surface) will typically be the circumferential length of the cylindrical body portion of the mandrel or levitation device plus the overlap length. Alternatively, a double overlap joint can be provided with suitable recesses on the mandrel surface. Figures 1506 and 1507 show a compression belt 1509 applied and secured with a tensioner 1510. A heating system for the overlapping joint is not shown, but is well known to those skilled in the art. Alternative means of providing external compressive force on the skin are pneumatic systems, hydraulic systems, and other mechanical arrangements. A key characteristic of the mandrel is that it should have suitable strength to prevent excessive movement or jolting under appropriate external compressive loads, thus forming a good joint.

[0117] Figure 16 The diagram illustrates the formation of several cylindrical body segments. 1600 shows two mandrels 1694 and 1605, 1601 shows a skin element 1606 placed on mandrel 1604, 1602 shows the same skin element 1606 now formed as body segment 1607 and an adjacent body element 1608, and body element 1609 is compressed onto mandrel 1605, which has been moved along a guide rail through processes such as forming, shrinking, repositioning, expanding, and shaping.

[0118] Figure 17 The initial formation of the conical mandrel is shown to allow for the initial formation of a transitional body segment (as shown in 1701), followed by the formation of a conical segment in 1702. In this system, the left mandrel used to form the conical segment ( Figure 16 1604 in the middle has been removed through the large mandrel 1605 or through the smaller orifice in the tapered mandrel.

Claims

1. An airship having an elongated hollow body having a length defining a local axis of the body, the hollow body being adapted to receive a gas lighter than air such that the airship becomes buoyant in air, the airship body comprising a series of multiple joined body portions, each body portion comprising an outer skin and a hollow internal space, wherein, The joint is substantially perpendicular to the local axis of the body, and the joined body portion includes two end body portions and multiple internal body portions, such that the joined body portions together form the elongated hollow body.

2. The airship according to claim 1, wherein, The length extends between the upper and lower ends during use, and the two end body portions provide both the upper and lower ends of the body.

3. The airship according to claim 1 or claim 2, wherein, The outer skin includes a metal foil layer sandwiching a first unidirectional fiber layer embedded in a cured resin matrix and a second unidirectional fiber layer embedded in a cured resin matrix, wherein the second unidirectional fiber layer is oriented at an angle to the first unidirectional fiber layer.

4. The airship according to claim 3, wherein, The metal foil is the outermost layer of the outer skin.

5. The airship according to claim 3, wherein, The skin comprises an outermost metal foil layer and an innermost metal foil layer, with a cured resin and fiber layer sandwiched between them.

6. The airship according to any one of the preceding claims, wherein, At least one pair of adjacent mating body portions are joined together to form a continuous skin area with a mating line therebetween, wherein at least one additional skin panel is positioned to cover the innermost and / or outermost layer of the mating line, the position of the at least one additional skin panel providing the mating area.

7. The airship according to claim 6, wherein, The adjacent joint body portion has removed some or all of the metal foil layer within the joint area.

8. The airship according to claim 6 or claim 7, wherein, The at least one additional skin panel does not have an innermost metal foil layer.

9. The airship according to any one of claims 6 to 8, wherein, Each joint area extends a certain length from the joint line, the length being 5 to 150 times, preferably 5 to 50 times, the thickness of the outer skin outside the joint line.

10. The airship according to any one of the preceding claims, wherein, At least one pair of adjacent joined body portions overlap each other to form a continuous outer skin region with an overlapping area, wherein at least one additional skin panel is placed to cover the overlapping area.

11. The airship according to claim 10, wherein, One or both of the adjacent body parts have some metal foil removed in the overlapping area.

12. The airship according to claim 10 or claim 11, wherein, The at least one additional skin panel does not have an innermost metal foil layer.

13. The airship according to any one of the preceding claims, wherein, Each joined body panel has an outer skin thickness of 0.1 to 5 mm, preferably 0.1 to 3 mm, more preferably 0.2 to 2 mm.

14. The airship according to any one of the preceding claims, wherein, The multiple internal body parts are substantially the same.

15. The airship according to any one of the preceding claims, wherein, At least 70% of the surface area of ​​the body portion has a minimum principal curvature of zero, and a maximum principal curvature of non-zero.

16. The airship according to any one of the preceding claims, the airship comprising 5 to 500 internal body parts.

17. The airship according to any one of the preceding claims, wherein, Each internal body section has a dimension of 30 to 4000 cm in the direction perpendicular to the length of the body.

18. The airship according to any one of the preceding claims, wherein the airship is positioned at an off-ground location.

19. The airship according to any one of the preceding claims, the airship comprising a tether connecting the airship to a substantially horizontal position on the ground.

20. The airship according to any one of the preceding claims, wherein, When the upper end is positioned substantially vertically above the lower end in use, the elongated body has a horizontal cross-section at each point along substantially its entire length, the horizontal cross-section being a wing surface, thereby providing a leading edge and a trailing edge extending between the upper end and the lower end, and between them, for each horizontal cross-section, defining a chord line between the leading edge and the trailing edge of the cross-section, the chord line having a chord length.

21. The airship according to any one of the preceding claims, wherein, When viewed horizontally perpendicular to the wind direction, the drag coefficient, defined by the ratio of aerodynamic drag to dynamic pressure in the planar region of the airship, is less than 0.35, preferably less than 0.2, and more preferably less than 0.

06.

22. The airship according to any one of the preceding claims, wherein, The length of the airship is 5 to 500 m.

23. The airship according to any one of the preceding claims, wherein, The body portion is formed by strips of material joined together at their ends.

24. The airship according to any one of the preceding claims, wherein, When the upper end is vertically positioned above the lower end during use, the elongated body includes a region oriented at an angle to the vertical direction.

25. The airship according to claim 24, wherein, The airship body is a wing surface, and the leading edge and the trailing edge are located in a single vertical plane in a region oriented at an angle to the elongated axis.

26. The airship according to claim 25, wherein, The trailing edge is farther away from the vertical line extending between the highest and lowest points than the leading edge.

27. The airship according to any one of the preceding claims, the airship comprising a tail portion manufactured as a separate pressurized hollow container.

28. A method for manufacturing an airship according to any one of the preceding claims, the method comprising the following steps: Support the first body portion to form a first installed hollow body portion; support the second body portion to form a second installed hollow body portion; The first mounted body portion and the second mounted body portion are brought into contact so that the outer skins of the first body portion and the second body portion are aligned; then the outer skins of the first body portion and the second body portion are joined together; then the process is repeated with another body portion, thereby producing the airship having an elongated hollow body.

29. The method according to claim 28, wherein, The outer skin alignment is such that the outer skin is aligned with an accuracy within three skin thicknesses, preferably within two skin thicknesses, and most preferably within one skin thickness.

30. The method according to claim 28 or claim 29, wherein, The outer skin of the body portion includes a metal foil layer prior to bonding, which sandwiches a first unidirectional fiber layer embedded in a cured resin matrix and a second unidirectional fiber layer embedded in a cured resin matrix, wherein the second unidirectional fiber layer is oriented at an angle to the first unidirectional fiber layer.

31. The method of claim 28, comprising the following steps: The first body portion is placed in the first support frame to form the first installed hollow body portion, and the second body portion is placed in the second support frame to form the second installed hollow body portion.

32. The method according to claim 31, wherein, Internal tension straps are attached to the interior of the outer skin of some or all of the early body parts, and then other body parts are joined to the early body parts.

33. The method according to claim 31 or claim 32, wherein, Each of the support frames includes at least one support edge parallel to the joint, the support edge being in contact with the periphery of the outer skin of the mounted body portion near the joint, preferably spaced 10 to 50 mm from the joint.

34. The method according to claim 33, wherein, The body portion is initially loosely held by the supporting edge to allow the position of the body portion to be adjusted before it is tightly held during engagement.

35. The method of claim 28, comprising the following steps: The first body portion is placed around the first support mold portion to form the first installed hollow body portion, and the second body portion is placed around the second support mold portion to form the second installed hollow body portion.

36. The method according to claim 35, wherein, The supporting mold is axially symmetric about a local axis of the body.

37. The method according to claim 35 or claim 36, wherein, The support mold is mounted on a guide rail parallel to the local axis.

38. The method according to any one of claims 35 to 36, wherein, The support molds are adjustable, making them expandable and contractible to provide support molds of variable size.

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