A Zeppelin of the size of the LZ Hindenburg on a flight from Frankfurt am Main to Lakehurst consumed approximately 54 tonnes of diesel with a buoyancy equivalent of 48, cubic metres of hydrogen, which amounted to about a quarter of the lifting gas used at the start of the flight , cubic metres. After the landing, the jettisoned hydrogen was replaced with new hydrogen. The Zeppelin NT has no special facilities to offset the extra buoyancy by fuel consumption. Compensation takes place by using a start-weight that is higher than the buoyancy lifting level at the start and during the flight, the extra dynamic buoyancy needed for lift-off and flight is produced with engines.
If, during the trip, the ship becomes lighter than air because of fuel consumption, the swivel engines are used for down pressure and landing. The relatively small size of the Zeppelin NT and a range of only kilometers compared to the historical Zeppelins allowed the waiver of a ballast extraction device. Different attempts were made on hydrogen airships: the LZ and LZ to use part of the lifting gas as a propellant without much success, later ships filled with helium lacked this option.
Around Blau gas was a common propellant for airships; it is named after its inventor the Augsburger chemist Hermann Blau who produced it in the Augsburger Blau gas plant. Various sources mention a mixture of propane and butane. The Zeppelins used a different gas mixture of propylene , methane , butane, acetylene ethyne , butylene and hydrogen. The LZ Graf Zeppelin had bi-fuel engines and could use gasoline and gas as a propellant. Twelve of the gas cells were filled with a propellant gas instead of lifting gas with a total volume of 30, cubic metres, enough for approximately flight hours.
The fuel tank had a gasoline volume of 67 flight hours. Using both gasoline and Blau gas could give hours cruise. In some airships rain gutters were fitted to the hull to collect rainwater to fill the ballast water tanks during flight. Methods and systems that implement the embodiments of the various features of the invention will now be described with reference to the drawings. The drawings and the associated descriptions are provided to illustrate embodiments of the invention and not to limit the scope of the invention.
Throughout the drawings, reference numbers are re-used to indicate correspondence between referenced elements. In addition, the first digit of each reference number indicates the figure in which the element first appears. In the following description, certain terminology is used to describe certain features of one or more embodiments of the invention.
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In one embodiment, the airship may be a lenticular shaped airship without any internal structural support members to maintain the lenticular shape. In one embodiment, the airship may include, but is not necessarily limited to, an outer tube formed in the shape of a toroid and one or more compartments positioned within the outer tube. The tube may be formed in the shape of, for example, a cylinder, a toroid, or any other shape capable of containing a gas. The tube may be capable of withstanding an internal pressure of between about 1 inch and about 7 inches of water at an altitude of about 65, feet and higher relative to sea level.
The BCS employs one or more mechanisms to actively control the static weight and hence the ascent or descent of the airship Additionally, the BCS is used to compensate for various external factors that might affect the static weight of the airship , such as a change in ambient atmospheric conditions, the consumption of fuel, a change in the level of superheat of the helium gas, or the offloading of passengers and cargo.
The BCS advantageously overcomes many of the drawbacks and inefficiencies of conventional vertical control mechanisms such as ballasting, gas release, dynamic lift and vectored engine thrust. The BCS does not require the carrying of excess weight, or the release of lifting gas, to compensate for expected weight changes of the airship during flight, or the use of dynamic lift or vectored engine thrust. The various BCSs may compensate for changes in operating conditions e.
For example, a pilot may operate the BCS to compensate for a change in the static weight of the airship caused by superheat, whether on the ground or in flight. In one embodiment, the superheat may be absorbed as pressure, which will not affect the static weight or the altitude of the airship The airship may include an outer tube made of a gas-impermeable, flexible, inelastic e. Sufficiently pressurized, the outer tube provides rigidity to the airship without requiring a separate rigid internal framework.
In one embodiment, the outer tube may be made of a rigid composite material such as a carbon fiber material, a Kevlar material or an M5 material or a flexible membrane material.
How do airships work? - LuffShips
The outer tube may be configured in the shape of a cylinder, a toroid, and various other aerodynamic shapes. The outer tube may be designed to contain one or more gases e. The gases may provide all or most of the lift so that little or no additional energy is expended to make the airship airborne. The gases may be pressurized to create the buoyancy control. In one embodiment, the gas within the outer tube may be pressurized to a pressure greater than the atmospheric pressure. For example, the gas may be pressurized to greater than 2 psi.
One advantage of the design is manufacturing simplicity. For example, a toroidal or lenticular geometry makes the design and manufacture of the BCS relatively simpler than conventional designs. Another advantage of the design is that the toroid or lenticular shape can better withstand the internal pressures associated with the BCS. The airship may include one or more compartments positioned within the outer tube The area outside the compartments but within the outer tube contains a lifting gas Hence, the outer tube may be made of a gas-impermeable material.
Each compartment may be made of a gas-impermeable, flexible, inelastic e. In one embodiment, the one or more compartments may be made of a polyurethane material. The one or more compartments may be fastened to the outer tube using an adhesive such as glue, one or more tie-downs or attachment points, or a combination thereof. The size and shape of each compartment can vary depending on the size, shape and weight of the airship and the materials available.
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In FIG. The area around the four 4 compartments a - d contains a lifting gas In some embodiments, the airship may include a compartment that extend around a portion of the outer tube or the entire outer tube and that is capable of holding air The area exterior to and around the compartment but within the outer tube contains air When filled with air , the compartment may extend to partially fill the outer tube If the operator desires the airship to descend or remain grounded, one or more compartments are filled with air to increase the static weight of the airship Conversely, if the operator desires the airship to ascend, air is released from the one or more compartments The lines allow the flow air to travel between the one or more compartments and the outside atmosphere.
In one embodiment, the airship may include a control device e. The control device may be programmed before the flight of the airship or a pilot on the ground or in the airship may use the control device to actively control the flight and operations of the airship The control device may be located on the airship or may be located on the ground allowing for remote control of the airship The remote control of the airship allows the airship to be an unmanned airship for military and surveillance purposes. In one embodiment, the lifting gas may be contained in the outer tube and the air may be contained in the one or more compartments When the airship is on the ground, the one or more compartments may be filled or partially filled with air As the amount of air in the one or more compartments increases, the internal pressure within the outer tube also increases.
As the amount of air in the one or more compartments decreases, the internal pressure within the outer tube also decreases. However, the outer tube maintains an internal pressure greater than atmospheric pressure even when there is no air in any of the compartments , such that the outer tube maintains its rigidity and continues to provide adequate structural support for engine pylons and the airship as a whole.
The engine pylons can be attached to an outer surface of the outer tube Referring to FIGS. The inner surfaces of the outer tube , the bottom cover and the top cover defines a central opening The bottom cover and the top cover may each be a circular piece of composite or fabric e.
Aeros Tests Pelican Variable-Buoyancy Airship
In one embodiment, the bottom cover and the top cover are made of a gas-impermeable, flexible, inelastic material. In one embodiment, the bottom cover and the top cover may be made of a rigid composite material such as a carbon fiber material, a Kevlar material or an M5 material or a flexible membrane material. The material of the bottom cover and the top cover may be the same or similar to the material of the outer tube The top cover is circumferentially coupled e. With the bottom and top covers and , the airship has a lenticular shape.
The central opening may be used to hold helium under an internal pressure. A blower , preferably located within the central opening , may be used to maintain an internal pressure within the central opening sufficient to give a convex shape to the bottom cover and the top cover In one embodiment, the internal pressure within the outer tube is greater than the internal pressure within the central opening This is because the bottom cover and the top cover can deform the outer tube with less pressure.
Propellers may be coupled to the engine pylon which is coupled to the outer tube for providing yaw control to the airship In one embodiment, the airship may include a cabin not shown positioned inside or outside the central opening to house an operator, passengers, cargo, equipment, a control room, etc. If the cabin includes an operator or passengers, the cabin may need to be pressurized accordingly. Referring to FIG. A number of catenary cables and may be used to unload or divert the internal pressure from the top and bottom covers and to the outer tube A first set of diagonally positioned catenary cables e.
A second set of diagonally positioned catenary cables e. A set of vertically positioned catenary cables may be attached between the top and bottom covers and For example, the central opening can 1 be empty; 2 contain, but is not limited to, a lifting gas such as helium and a passive ballonet system; or 3 contain, but is not limited to, a lifting gas such as helium and a BCS system that operates on the same or similar principles as the outer tube and the one or more chambers described above.
When the central opening is empty, the airship may or may not include the bottom cover and the top cover Without the bottom and top covers and , the airflow over the airship may be disrupted, resulting in an unstable flight. The bottom and top covers and allow smooth airflow over the airship i. In this configuration, the airship may include the blower to maintain an internal pressure within the central opening sufficient to give a convex shape to the bottom cover and the top cover The central opening may include a lifting gas and a passive ballonet system That is, the central opening may be filled with a lifting gas such as helium.
The passive ballonet system may include one or more compartments capable of being filled with air The most common gas in use today is helium, which has a lifting capacity of 0. Hydrogen was commonly used in the early days of airships because it was even lighter, with a lifting capacity of 0. However, the Hindenburg disaster ended the use of hydrogen in airships because hydrogen burns so easily. Helium, on the other hand, is not flammable. While these lifting capacities might not seem like much, airships carry incredibly large volumes of gas -- up to hundreds of thousands of cubic feet thousands of cubic meters.
With this much lifting power, airships can carry heavy loads easily. A blimp or airship controls its buoyancy in the air much like a submarine does in the water. The ballonets act like ballast tanks holding "heavy" air. When the blimp takes off, the pilot vents air from the ballonets through the air valves.