Abstract: Torsion box of an aircraft stabilizing surface comprising a front spar (15), a rear spar (17), ribs (21) and upper and lower stiffened skins, in which at least one of the skins (31) is stiffened with a plurality of stringers (33, 43), preferably omega-shaped stringers, extending all of them along the full skin span, preferably in a convergent distribution, and having a decreasing cross section towards the skin outer edge.

Abstract: It presents the novelty that the duct (6) for the exhaust (4) comprises at least two telescopic sections (5) with their corresponding perimetric acoustic cavities (7), in order to permit the length of the duct (6) to be varied and achieve a required attenuation of the noise produced in the combustion. By extending the sections (5) the attenuation of the noise is increased and by retracting them it is decreased, obtaining an exhaust (4) that is adapted to the needs of the noise required in each moment. It is applied to the exhaust of the APU of an aircraft, designed with the smaller dimensions of the exhaust (4) improving the aerodynamic conditions of the aircraft. So when the aircraft is in flight, in which the requirement of noise attenuation is less, the exhaust (4) is maintained in its retracted position, while when the aircraft is on the ground it is extended for greater attenuation of the noise, as is required on ground.

Abstract: An Auxiliary Power Unit (APU) includes a power module (1) to be supplied with fuel (2), a gearbox (5), an electric generator (6), and an element selected from a compressor (4), a hydraulic pump and a combination thereof, in order to provide a functioning mode for production of power selected from electric (8), pneumatic (7), hydraulic and a combination thereof; the APU presents the novelty of including an electric motor (9), integrated into the electric generator (6), with the electric motor (9) and the electric generator (6) connected to the power module (1) via the gearbox (5a) and a main clutch (10). Moreover, the compressor (4) and/or the hydraulic pump are also connected to the power module (1) via the gearbox (5a) and the main clutch (10). Also, the compressor (4) and/or hydraulic pump are connected to the power module (1) via the gearbox (5a) and the main clutch (10).

Abstract: It consists of two electrically fed pneumatic independent compressors (CAC) (2) which are connected to an independent controller of (CACs) (5), an auxiliary power unit (APU) (3) sized for independently feeding each (PACK) (1) in the operations of the aircraft both on the ground and in flight, which is connected to an independent controller of (APU) (6) and a central controller (12) connected to the controllers (5 and 6) so that the (PACKs) are individually fed either by a (CAC) (2) or by the (APU) (3) and in such a way that a single (PACK) (1) is fed or several of them.