Aeronautics and astronautics – Aircraft – heavier-than-air – Airplane and fluid sustained
Reexamination Certificate
2000-09-11
2002-05-07
Barefoot, Galen L. (Department: 3644)
Aeronautics and astronautics
Aircraft, heavier-than-air
Airplane and fluid sustained
C244S030000, C244S039000, C244S052000
Reexamination Certificate
active
06382557
ABSTRACT:
The invention relates to a lighter-than-air aerostat, of the type comprising at least one main chamber closed in a sealed manner, with a constant volume, which is pressurised by a gas lighter than air, such as to permit rising and flight of the aerostat. Throughout the present application, “aerostat” means any vehicle lighter than air, and “geostationary” means the fact that an aerostat remains at least substantially vertical relative to a point which is fixed in relation to the ground.
So-called free aerostats are those which are not connected mechanically to the ground, unlike captive aerostats. Conventional free balloons have the disadvantage that they drift, in particular horizontally, in relation to the ground, according to the winds, without any possibility of controlling their position or their path. Captive balloons do not have this disadvantage, and are at least substantially geostationary. However, they require at least one cable for connection to the ground, which is heavy and triangulated, is a source of danger for air traffic, and in practice prevents selection of this technology for aerostats which are designed to fly at a high altitude, and in particular for stratospheric aerostats.
If it is required to be able to pilot the horizontal position (i.e. the position relative to the ground) and/or the horizontal path of a free aerostat for a long period of time (ranging from a few months to several years), it is out of the question to have on board consumable energy. With solar energy, the problem must be faced of the weight of the collector devices and of the means of storage, taking into account firstly the fact that the efficiency of the electric motors (in particular the ratio of the thrust to the power consumed) is too low, and secondly the night flight which must be assured.
In addition, since free aerostats are extremely sensitive to meterological conditions and horizontal winds, a very large inflated volume must be provided, in order to be able to carry on-board position-correction motors, the power of which makes it possible to compensate for the horizontal aerodynamic drag.
In particular, it is known that a stratospheric geostationary balloon would require a minimum volume of approximately 350,000 m
3
, and a minimum weight of approximately 10 tonnes, in order to be able to carry motors making it possible to control its horizontal position and/or its horizontal path at a stratospheric altitude, as well as a useful load such as a telecommunications system. Dimensions of this type represent a substantial volume, and a significant risk for air traffic, and for the populations, if the balloon falls or is destroyed. In addition, these dimensions cause problems of practical production and launching. In addition, the assembly would have a high cost, for relatively low reliability.
However, long-lasting stratospheric missions would permit scientific study of the upper atmosphere, observation of the earth, improvement of telecommunications, etc. In particular, it is desirable to be able to have at a stratospheric altitude numerous devices which can act as active or passive relays for hertzian connections, for example for telecommunications satellites (mobile telephony, radio, television, data networks, etc) or localisation satellites (GPS, Argos systems, etc).
Therefore, there is a need to be able to place vehicles at a high atmospheric altitude, and in particular at a stratospheric altitude, the position or displacements of which relative to the ground, in particular horizontally, can be controlled automatically or from the ground, without a human pilot on board, for a duration which can be between a few days and several years.
The object of the invention is thus to eliminate these disadvantages, by providing a free vehicle which is designed for a high atmospheric altitude, and in particular a stratospheric altitude, and of which the horizontal position (in longitude and latitude) and/or the horizontal displacements relative to the ground can be controlled automatically, autonomously or from the ground, for a substantial period of time.
In particular, the object of the invention is to solve the problem posed by the energy necessary for motorisation, which makes it possible to maintain the horizontal position and/or to follow a horizontal path.
More particularly, the object of the invention is to provide a vehicle of this type, formed from an aerostat which is designed for a high atmospheric altitude, and in particular a stratospheric altitude, the volume of which is limited, and in particular is between 10 m
3
and 10,000 m
3
, for example approximately 2,000 m
3
, for a weight of between 10 kg and 500 kg, and in particular between approximately 50 kg and 200 kg.
In addition, the object of the invention is to provide an aerostat which is particularly suitable for acting as an active and/or passive relay for transmission of data by hertzian means, in particular in the field of hyperfrequencies.
For this purpose, the invention relates to a lighter-than-air aerostat, comprising:
a strengthening structure, which defines a shape which is symmetrical relative to a main axis;
at least one main chamber closed in a sealed manner, which is integral with the said structure, and is pressurised by a gas which is lighter than air, such as to permit flight of the aerostat;
means for driving the aerostat comprising:
one or a plurality of particle-emission propulsion units supported by the said structure, which are regularly distributed around the main axis, and are designed to be able to drive the aerostat in rotation in one direction around the main axis, and to be able to be controlled from an active state to an inactive state and vice-versa, at least once for each rotation of the aerostat around the main axis;
one or a plurality of mobile flaps, which are supported by the said structure outside the main chamber, are distributed regularly around the main axis, and are designed to be able to be controlled at least once for each rotation of the aerostat around the main axis, from an active state, in which they brake the rotation of the aerostat, whilst exerting aerodynamic thrust which tends to displace the aerostat in translation perpendicularly relative to the main axis, to an inactive state, in which they do not offer any substantial resistance to the rotation of the aerostat, and vice versa; and
on-board control means, which are designed to control the propulsion units and the flaps in order to
drive the aerostat in continuous rotation around the main axis; and
drive the aerostat in translation, with at least one component which is perpendicular to the main axis, relative to the volume of air in which it moves.
“Translation with at least one component perpendicular to the main axis” means movement of translation in a direction of translation which has a component which is non-zero, according to the direction which is radial relative to the main axis, i.e. which is not parallel to the main axis. Preferably, advantageously and according to the invention, the means for driving the aerostat are designed to drive the aerostat in translation in a direction of translation which is at least substantially radial relative to the main axis, i.e. which is perpendicular to the main axis.
Advantageously, an aerostat according to the invention has an overall axial dimension parallel to the main axis which is smaller than that of its overall radial dimension perpendicular to the main axis. Preferably, and according to the invention, it has a general outer shape which is globally symmetrical in revolution around the main axis, and in particular is globally lenticular.
In one embodiment, and according to the invention, the aerostat has an overall radius of between 5 m and 50 m, and in particular approximately 15 m, and an overall axial height of between 1 m and 20 m, and in particular approximately 10 m.
Advantageously and according to the invention, the aerostat comprises at least one ionic actuator and/or at least one air pulsation unit, as a particle-emission propulsion unit, these particle
Evrard Jean François Joseph
Lafuma Pierre
Mercier Flavien Michel François
Vargas Andre
Barefoot Galen L.
Centre National d'Etudes Spatiales (C.N.E.S.)
Young & Thompson
LandOfFree
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