Helicopter equipped with a device for emergency lift assistance

Abstract

The invention relates to a helicopter including a structural framework, at least one main rotor for lift and propulsion integral with said structural framework and a drive train for driving said main rotor including a power transmission gearbox and at least one main engine, wherein it further includes a plurality of extra booster power units fixed to said structural framework and configured so as to be able to supply extra lift of the helicopter in case of failure of the helicopter's drive train.

Claims

1. A helicopter comprising a structural framework, at least one main rotor for lift and propulsion integral with said structural framework and a drive train for driving said main rotor comprising a power transmission gearbox and at least one main engine, further comprising a plurality of extra booster power units fixed to said structural framework and configured so as to be able to supply extra lift of the helicopter in case of failure of the helicopter's drive train, wherein each of said extra booster power unit is mounted detachably on the structural framework and wherein the structural framework further comprises upper frames arranged in the vicinity of the main rotor for lift and propulsion, and in that said extra booster power units are fixed on said upper frames.

2. The helicopter according to claim 1 wherein each of said extra booster power unit is mounted detachably on the structural framework by detachable fixing means.

3. The helicopter according to claim 1, wherein the helicopter comprises four extra booster power units uniformly distributed on said structural framework.

4. The helicopter according to claim 1, wherein said extra booster power units comprise pyrotechnic devices.

5. The helicopter according to claim 1, wherein the helicopter comprises a control unit connected to each of said extra booster power units and configured for controlling the activation of each of said extra booster power units in case of a failure in the helicopter's drive train.

6. The helicopter according to claim 5, wherein said control unit is configured so as to be able to activate the extra booster power units automatically as the ground is approached.

7. The helicopter according to claim 1, wherein said extra booster power units are configured so that each one is able to supply identical propulsive power and in that said extra booster power units are arranged and oriented on said structural framework in such a way that said extra booster power units exert thrust forces in directions intersecting at a single point, called the convergence point (C).

8. The helicopter according to claim 7, wherein said convergence point (C) is arranged at the centre of the rotor in the plane of the rotor blades, in such a way that the resultant of the thrust forces of the extra booster power units is vertical and is applied at the top of a rotor mast.

9. The helicopter according to claim 7, wherein said convergence point (C) is the centre of gravity of the helicopter.

Description

5. LIST OF FIGURES

(1) Other aims, features and advantages of the invention will become clear on reading the following description, given purely non-exhaustively, and referring to the appended figures, in which:

(2) FIG. 1 is a schematic view of a helicopter intended to be equipped with a device for emergency lift assistance to form a helicopter according to one embodiment of the invention,

(3) FIG. 2 is a partially sectioned schematic view of a helicopter according to one embodiment of the invention

(4) FIG. 3 is a partially sectioned schematic view of a helicopter according to another embodiment of the invention.

6. DETAILED DESCRIPTION OF ONE EMBODIMENT OF THE INVENTION

(5) In the drawings, scales and proportions are not strictly observed, for purposes of illustration and clarity. Throughout the following detailed description, with reference to the figures, unless stated otherwise, each element of the helicopter is described as it is arranged when the helicopter is horizontal. This arrangement is shown in FIGS. 1 to 3.

(6) Furthermore, the identical, similar or analogous elements are denoted by the same references in all the figures. Finally, the terms longitudinal, transverse and vertical are used non-exhaustively with reference to the L, T, V axis system as shown in the figures. The longitudinal direction corresponds to the principal direction of the helicopter.

(7) FIG. 1 shows a helicopter comprising a structural framework 5. This structural framework 5 is shown with dotted lines in FIG. 1. This framework forms the airframe of the helicopter and comprises upper frames 6, pillars 7, lower frames 8, cross-beams, etc., assembled together to form the airframe of the helicopter.

(8) The helicopter also comprises a main rotor 10 for lift and propulsion integral with the structural framework 5. The rotor 10 is coupled to blades 9 for lift and propulsion. The helicopter also comprises a drive train for driving the main rotor 10. This drive train comprises a power transmission gearbox 11 and two main engines 12a, 12b.

(9) FIG. 2 is a schematic view of a helicopter according to one embodiment of the invention obtained starting from the helicopter in FIG. 1. This view is sectioned to reveal the upper frames, pillars, lower frames, cross-beams, etc. of the structural framework 5. This helicopter comprises, in addition to the members and elements described in connection with FIG. 1, four extra booster power units 21a, 21b, 21c, 21d fixed on the upper frames 6 of the structural framework 5. Each power unit is configured so as to be able to supply, on command, extra lift of the helicopter in case of failure of a main engine 12a, 12b of the helicopter.

(10) The power units are for example pyrotechnic rockets comprising a solid propellant gas generator, a device for igniting the solid propellant and a nozzle for discharge of the gases. Any other type of power unit may be used for implementing the invention.

(11) Preferably, all the power units are identical and are configured so as to be able to supply the same power. They are fixed detachably on the upper frames 6 of the structural framework 5, for example by means of fixing collars equipped with a system of the screw-nut type. Furthermore, they are oriented downwards so that they exert a downward thrust force. The thrust produced by each power unit 21a, 21b, 21c, 21d is shown schematically in FIGS. 2 and 3 by an arrow with the reference letter P.

(12) According to an advantageous embodiment, the supply of lift from each power unit is moderated. For this purpose, the power unit is configured so that the maximum power that it can produce is of the order of 20% of the maximum power of a main engine of the helicopter, and for a time of the order of 30 seconds. The power units are only intended to slow the descent of the helicopter for a brief moment, in the vicinity of the ground, and not to provide continuation of flight in case of failure of one or more main engines of the helicopter.

(13) FIG. 3 is a schematic view of a helicopter according to another embodiment of the invention in which the extra booster power units 21a, 21b, 21c, 21d are arranged and oriented on the structural framework 5 in such a way that they exert thrust forces P in directions intersecting at a single point, called the convergence point. This point is referenced with the letter C in FIG. 3. The view in FIG. 3 is also sectioned to reveal the upper frames, pillars, lower frames, cross-beams, etc. of the structural framework 5. In the embodiment in FIG. 3, the convergence point C is arranged at the centre of the rotor 10 in the plane of the blades 9. According to this embodiment, the resultant of the thrust forces P of the extra booster power units 21a, 21b, 21c, 21d is vertical, which limits any risk of rolling and of rotation of the helicopter.

(14) The activation of the power units can be controlled by a control unit connected to each booster power unit and configured for controlling the activation of each booster power unit in case of a failure in the helicopter's drive train.

(15) This control unit may also be connected to a device for detecting the altitude of the helicopter such as an altimeter or any equivalent device. This control unit may also be controlled manually by the pilot during the mission if necessary, for example in case of emergency, to avoid an obstacle or take evasive action under enemy fire.

(16) According to an advantageous embodiment, the thrust axis of the power units may be orientable using means of the nozzle or flap type, to ensure horizontal attitude of the helicopter.

(17) The invention is not limited just to the embodiments described. The invention also applies to a single-engine helicopter. The invention may also comprise more (or fewer) than four extra booster power units for supplying emergency lift assistance.

(18) Moreover, the detailed description describes power units fitted on the upper frames of the structural framework of the helicopter. According to other embodiments not shown, the power units may of course be arranged at any point of the structural framework, notably on the helicopter skids.