Abstract: The invention seeks to provide a dirigible balloon with an internal enclosure (V2) having a flexible wall (4) contained in an outer rigid enclosure (15) which is of aerodynamic shape. The internal enclosure (V2) contains helium and is provided with means (5, 6, 7, 8) enabling its volume to be modified. Thus, depending on the volume given to the internal enclosure (V2) of the dirigible balloon, landing, take-off, and altitude variation are easy to perform. The means for modifying the volume of the internal enclosure (V2) comprise a cable (8) connected to the internal enclosure (V2) by means of a set of pulleys (5, 6), and a winch (7) for reducing the length of the cable (8).

Abstract: A variable-lift device using a helium to fly. The device comprises a balloon (1) composed of an outer flexible envelope (3) supported by a rigid structure. The rigid structure comprises a plurality of hollow toruses (4) of inside volume that acts as a tank for storing helium under pressure.