Aeronautics and astronautics – Aircraft – lighter-than-air – Airships
Reexamination Certificate
2000-03-28
2001-10-23
Jordan, Charles T. (Department: 3644)
Aeronautics and astronautics
Aircraft, lighter-than-air
Airships
C244S097000
Reexamination Certificate
active
06305641
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention generally relates to a super-pressured high-altitude airship and more specifically, to a high-altitude airship of super-pressure structure which flies in the stratosphere, is propelled against the wind with the power obtained through the photovoltaic conversion of the sunlight, generally allows no in-flow or out-flow of the gas in an airship hull (a gas bag) from or to, respectively, the atmosphere in the stratosphere, is a large-scale LTA (Lighter-Than-Air) platform for observation for the global environmental protections and for telecommunication relay, copes with the temperature fluctuations of the buoyant gas with the pressure resistance, and keeps constant full volume even when the pressure of the buoyant gas if fluctuated.
2. Discussion of Background
Conventional scientific balloons allow expansion of internal helium gas since the balloons do not have air for venting when ascending, and the ascension occurs with an usable buoyancy by preventing a rise in internal pressure rise as compared with the atmospheric air outside of the balloons. In horizontal flight, the balloons are flown by the wind by dropping ballast to cope with the loss of buoyancy. When the balloons have to descend, the balloon skin is ripped in order to vent the buoyant gas, and the payloads descend by parachutes.
On the other hand, in the low stratosphere, namely at an altitude of about 20 km above ground level, the weather is fine throughout the year and the wind is relatively weak, so that it is effective to make a large-scale LTA platform fly in such a space for a long period of time for the purposes of environmental observation and telecommunication relay. In this case, it is difficult to apply a means used for the above-described scientific balloons, but it is necessary to have a propulsion power to keep a position of the platform against the wind in the stratosphere, and at the same time, a means is necessary for ascent and descent of the vehicle which enables high speed shuttling between the stratosphere and the ground.
In such a high-altitude airship, the volumetric increase/decrease caused by the temperature fluctuations, such as the super-heat of the buoyant gas affected by the solar radiation at high altitudes, should be absorbed by air-filled ballonets (i.e., air chambers) allowing air flow from/to the outside atmosphere, which are usually positioned fore and aft of the airship hull, and thereby the trim function of the pitch attitude is provided. For example, if a temperature fluctuation band of the buoyant gas is 70° C., and the mean temperature of the atmospheric air is about −53° C. (220° K in absolute temperature), the ballonet volume of not less than 70/220 of the hull volume is necessary, and as a result, the buoyancy of the ballonet space is lost and a weight is added by ballonet fabric materials, and the gas bag skin of the ballonet forms a free surface of the fluid boundary, namely between ballonet filled air and the buoyant gas in an envelope (airship hull body), which causes problems that the ballonet skin is exposed to the sloshing of the gas, and material fatigue of the fabric is apt to be caused by this kinetic movement.
SUMMARY OF THE INVENTION
Accordingly, it is one of the objectives of the present invention to solve such problems as described above, and basically to present a high-altitude airship suitable for a large-scale LTA platform which flies in the stratosphere, which is mainly propelled by the power obtained through the photovoltaic conversion of the sunlight, and which is effective for environmental observation, telecommunication relay, etc.
Another objective of the present invention is to provide a super-pressured high-altitude airship in which the hull (a gas bag) of the high-altitude airship allows no in-flow or out-flow of gas from or to, respectively, the outside atmosphere in the stratosphere, is capable of enduring the temperature fluctuations of the buoyant gas at a high altitude, is pressure-resistant, is of super-pressured structure to keep a constant hull volume even if the buoyant gas pressure inside of the hull is fluctuated, is free from the above-described ballonet disadvantages which could possibly lead to structural destruction buoyancy loss which minimizes the area and weight of fabric materials needed, and which simplifies the hull configuration.
Yet another objective of the present invention is to provide a super-pressured high-altitude airship capable of avoiding, as much as possible, the temperature fluctuations of the buoyant gas in the envelope caused by super heat, etc. effected by the solar radiation, and the fluctuation in volume (pressure) of the buoyant gas caused by the temperature fluctuation.
In order to achieve the above-mentioned objectives, the super-pressured high-altitude airship of the present invention is characterized by the gas bag, which forms an envelope that allows no in-flow or out-flow of a gas from or to, respectively, the outside atmospheric air at the mission altitude, is pressure-resistant so as to suppress the rise in internal pressure, and has a super-pressure structure to maintain the rigidity necessary for the envelope by the differential pressure between the internal pressure and the outside atmospheric pressure, and characterized in that a solar cell is placed on the upper external surface of the envelope, and a heating reduction means is provided below the installation surface of the solar cell to block the in-coming heat from the solar cell to the buoyant gas filled in the envelope and to prevent the internal pressure rise.
The heat reduction means in the above-described super-pressured high-altitude airship is provided to prevent the expansion of the buoyant gas by the super-heat due to solar radiation and the excessive pressure rise caused thereby, and comprises a ventilation space between the installation surface of the solar cell and the gas bag, and a ventilating means to forcibly circulate the outside air in this ventilation space. This ventilating means makes use of the excessively generated power by the above-described solar cell with the intense sunlight during daytime.
Further, the above-described envelope can be provided with a pitch attitude control means to trim the static balance of the pitch attitude angle of the airship hill by shifting a loaded weight in the longitudinal direction as necessary.
Since the hull of the super-pressured high-altitude airship of such a configuration is of super-pressure structure, only a pressure-resistant gas bag capable of enduring the temperature fluctuations at a high altitude may be provided, as compared with a conventional airship in which ballonets are separately installed at positions fore and aft of the hull to absorb the volumetric increase/decrease of the gas due to the temperature fluctuations at a high altitude, and as for the airship of the present invention, since the mission altitude is high and the atmospheric pressure is as low as 40-50 hPa, the strength of the gas bag may be smaller than that of an airship flying at a lower altitude with high atmospheric pressure, and the gas bag design is very simple in structure and easily operated. When the static balance control of the airship hull pitch attitude angle is necessary in place of the ballonets, the static balance can be regulated by shifting the loaded weight in the longitudinal direction by the pitch attitude control means.
In this super-pressure structure, when the buoyant gas temperature in the envelope is fluctuated, the internal pressure is also fluctuated by the temperature change, but since the heat blocking means, including the ventilation space and the ventilation means or similar, in order to forcibly circulate the outside air therein, are installed on the underside of the solar cell, which remarkably generates the heat due to the absorption of the sunlight, the heat transfer to the buoyant gas in the envelope is suppressed to minimize the pressure change by the temperature fluctuation of the buoyant ga
Agency of Industrial Science and Technology
Dinh Tian
Jordan Charles T.
Oblon & Spivak, McClelland, Maier & Neustadt P.C.
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