This application claims the benefit of the French patent application No. 1551014 filed on Feb. 9, 2015, the entire disclosures of which are incorporated herein by way of reference.
The invention relates to an aircraft tail cone.
Most aircraft incorporate avionic equipment in their tail cone.
This equipment comprises, for example, the systems for powering the control surfaces situated in the empennage, etc.
In some aircraft, the engines are disposed at the tail cone of these aircraft.
Thus, the tail cone incorporates equipment in addition to that listed above, namely, systems for powering the engines and auxiliary power units (APU), fuel (kerosene) circuits, hydraulic and electrical circuits, air circuits that supply the cabin with hot air which is taken from the engines and cooled, fire extinguishing systems and equipment (cylinders containing extinguishing agent), etc.
In the type of aircraft with aft-mounted engines, the tail cone is relatively longer than on aircraft having wing-mounted engines so as to be able to incorporate all of the equipment mentioned above.
Generally, aircraft tail cones (for aircraft with aft-mounted engines and with wing-mounted engines) are equipped, under the fuselage, with an access hatch. Such a hatch allows qualified operators to pass inside the tail cone and carry out inspection and/or maintenance operations on all or some of the avionic equipment present. For some equipment, the operations have to be carried out regularly, for example before each flight or at regular intervals.
However, it is frequently difficult for the operators to move around inside the tail cone on account of the space taken up by the equipment and thus the little space that is left free for the movement of persons.
The accessibility of the equipment in the tail cone to operators for inspection and/or maintenance operations is thus greatly limited.
As a result, inspection and/or maintenance operations take time. The difficulty of access also increases the risk of the equipment being damaged during maintenance operations.
In light of the above, it would thus be useful to make inspection and/or maintenance operations of the equipment housed in an aircraft tail cone easier.
Therefore, a subject of the present invention is an aircraft tail cone comprising a fuselage inside which avionic equipment is housed, characterized in that the tail cone comprises at least two lateral hatches which are formed in the fuselage, at least one lateral hatch being formed on each of the two opposite sides of the fuselage on either side of the longitudinal axis of the aircraft, the at least two lateral hatches each being mounted removably with respect to the fuselage so as to take up two positions, namely a closed first position in which each lateral hatch closes a lateral opening made in the fuselage, and an open second position in which each lateral hatch is open and allows access to the inside of the tail cone through the corresponding lateral opening, the avionic equipment which requires regular inspection and/or maintenance operations being housed in a part of the tail cone which is accessible from the outside of the fuselage through the two lateral openings in the fuselage.
The avionic equipment that requires regular inspection and/or maintenance operations is situated in a region of the tail cone which is accessible through each of the lateral openings made in the fuselage to a person who remains on the outside of the tail cone.
Most of this equipment is thus arranged in a region situated facing the lateral openings or in a region which is adjacent to this region and remains easily accessible from at least one of the openings.
According to further possible features considered in isolation or in combination with one another:
A further subject of the invention is an aircraft, characterized in that it comprises an aircraft tail cone as briefly set out above.
Further features and advantages will become apparent from the following description, which is given solely by way of nonlimiting example and with reference to the appended drawings, in which:
As shown in
The aircraft comprises a fuselage 12, a central airfoil 14 connected to the fuselage and a tail cone 16. The tail cone 16 comprises the rear part of the fuselage 18, an aft-mounted engine 20 connected to the rear part of the fuselage 18 and an empennage 22.
The aft-mounted engine in this case comprises, for example, an engine with contrarotating fans that is connected to the tail cone 16 by a pylon 24a fixed to the side of the tail cone shown in
Only one of the two opposite sides of the fuselage is shown in
The tail cone comprises two closed opposite ends, an upstream end and a downstream end that corresponds to the aft end of the aircraft.
As shown in
Each lateral hatch 26, 28 is mounted removably with respect to the fuselage so as to be able to take up at least two positions:
The lateral hatch 28 is situated under the pylon 24b (
In this first embodiment, the lateral hatches are mounted so as to slide with respect to the fuselage in the manner known for the lateral doors of a helicopter and open towards the rear as in the latter. It will be noted that the system for fastening these hatches to the fuselage is much simpler than that of a passenger door of an aircraft since, in this case, it is not a question of a pressurized zone. The structure of these hatches and the manner in which they are mounted will be explained in more detail with reference to the fourth embodiment illustrated in
The lateral hatches 26, 28 mounted in a sliding manner are “non-acting”, i.e., they are not involved in the transmission of force to the fuselage. These hatches are used when the inspection and/or maintenance operations are frequent.
The inside of the tail cone houses avionic equipment such as systems for powering the engines and auxiliary power units (APU), fuel (kerosene) circuits, hydraulic and electrical circuits, air-conditioning equipment and air circuits that supply the cabin with hot air which is taken from the engines and cooled, fire extinguishing systems and equipment (cylinders containing extinguishing agent), systems for powering the control surfaces that are situated in the empennage, computers, measurement systems (for example: the black boxes of the appliance, but also other types of sensors for carrying out possible measurements in flight), circuits for cooling the various fluids (oil, fuel), oil/fuel filters, systems for measuring fuel flow rates, any kind of valve for controlling the flow rates of these fluids, etc.
As shown in
The assembly 34 is housed in the tail cone downstream of the pressure bulkhead 25. Part of this assembly is situated in the vicinity of the pressure bulkhead. In the next embodiments an assembly of avionic equipment is also located behind the pressure bulkhead.
The avionic equipment which requires regular inspection and/or maintenance operations is thus housed in a part of the tail cone which is accessible from the outside of the fuselage through the four lateral openings in the fuselage.
By arranging the avionic equipment in such a way in this part of the tail cone, it is no longer necessary to provide, as in the prior art, an internal space in the tail cone for the movement of inspection and/or maintenance personnel. In the prior art, the avionic equipment in question was furthermore not collected together in this part of the tail cone and was sometimes even spread out within the tail cone. As a result, the internal dimensions and thus the external dimensions of the novel tail cone can be reduced.
This comparative view shows that the tail cone B is shorter and narrower (transverse dimension perpendicular to the longitudinal axis X) than the prior art tail cone A.
The shape and the dimensions of the lateral hatches and of their openings, and also the number and positions thereof are chosen in a suitable manner for the avionic equipment in the tail cone, for dimensions thereof and for the position thereof inside the fuselage. Thus, the openings are, in particular, dimensioned so as to allow the passage of equipment to be extracted from the tail cone or to be introduced into the latter.
It will be noted that the lateral hatches are structurally reinforced in a known manner so as to act as removable shields for protecting the avionic equipment inside the tail cone in the event of accidental loss of rotor blade(s) of each engine. The equipment situated behind these shields is thus protected, thereby making it possible to limit the systematic recourse to redundancy for all of the equipment with which the tail cone is equipped. A saving of on-board mass can thereby be obtained.
By way of example, the reinforced hatches are produced from the same material (for example aluminum, titanium) as that of the fuselage but with a greater thickness (for example, 5 to 15 mm, in particular, 10 mm) than that of the fuselage (for example, 1 to 3 mm) The thickness is chosen depending on the dimensions and the energy of the pieces of engine to be stopped. Alternatively, the material of the reinforced hatches can be based on carbon fibers or Kevlar.
In
It will be noted that the presence of a plurality of lateral hatches allows work to be carried out simultaneously on the avionic equipment inside the tail cone by way of all (saving of working time) or only some of these hatches.
According to a variant that is not shown, the lateral hatches slide forwards in order to be opened, thereby making it possible to afford additional safety as regards possible accidental opening in flight. However, the choice as to whether the hatches open towards the rear or towards the front depends in particular on the number and the position of all of the hatches (position of one hatch with respect to the others but also with respect to the pylon structure for supporting the engines).
In this embodiment, the lateral hatches 48, 50 are each mounted in an articulated manner on the fuselage by way of a hinge system 52, 54 of the type used for the aircraft nacelle fairings.
The opening of the lateral hatches 48, 50 frees up respective corresponding lateral openings 56, 58, the features of which are identical to those in the embodiment in
The lateral hatches 48, 50 mounted in an articulated manner are “non-acting”, i.e., they are not involved in the transmission of force to the fuselage. These hatches are used when the inspection and/or maintenance operations are frequent.
The lower position of the upstream hatches 50 and 50′ with respect to the downstream hatch 48 and to the symmetrical downstream hatch (not visible in the figures) allows them to be opened at the top while each being situated under the corresponding engine pylon 24b, 24a (
The higher position of the downstream hatches 48 and 48′ with respect to the upstream hatches 50 and 50′ and outside the region situated vertically below the corresponding engine pylon 24b, 24a allows these downstream hatches to be opened at the top with no risk of interfering with the pylon (
According to a variant embodiment shown in
As for the embodiments in the preceding figures, the tail cone comprises two lateral hatches 72, 74 on each side of the fuselage downstream of the pressure bulkhead 76 (e.g., flat).
Each lateral hatch can be formed by a single removable panel or a plurality of removable panels that are adjacent to one another and are each able to be opened and closed independently of one another.
In the example in
When necessary, each panel is removed and withdrawn in a simple manner without using complex tools in order to free up the opening which it covers (when it is mounted as shown in
When the inspection and/or maintenance of avionic equipment is carried out more regularly (for example, upon each flight), it is not desirable to remove and refit the removable panel(s).
Thus, each lateral hatch comprises one or more “non-acting” secondary hatches or flaps that each have a size smaller than that of the main hatch or of the panel which forms the latter.
In
Each flap is able to take up two positions, a closed first position in which the flap closes an opening, known as the flap opening, which is made in the lateral hatch/panel, and an open second position in which the flap is open and allows access to the inside of the tail cone through the flap opening In
These flaps of reduced dimensions make it possible, without it being necessary to remove and withdraw the corresponding hatch/panel, to see and access some of the equipment which is disposed behind the hatch and requires frequent work and/or inspections, for instance upon each flight.
The lateral hatches 72, 74 that act in a structural manner allow a saving of on-board weight to be achieved compared with non-structural lateral hatches for which the fuselage needs to be reinforced significantly around the hatches, in the same way as for a passenger door or cargo door.
In order to simplify the operations of removing and refitting the lateral hatches in the event of work being carried out, it is preferable to produce each hatch in the form of a plurality of fittable/removable panels, each with a reduced size, which will be easier to handle individually. Moreover, it is conceivable to only withdraw the necessary panel(s) for the work to be carried out and not, systematically, all of the panels.
In
As in the case of the embodiments in
It will be noted that the size, the number and the position of the flaps can vary depending on the arrangement of the equipment situated behind the hatch in question, the number thereof and the size thereof.
Each hatch can take up a closed position in which the hatch closes a bulkhead opening that is made in the bulkhead, and an open position allowing access to the inside of the tail cone through the bulkhead opening
In this example, each hatch 84, 86 is mounted so as to slide on the bulkhead with a top closed position (
A person 92 situated in front of the bulkhead 82 and tasked with carrying out inspection and/or maintenance operations (
The bulkhead 82 equipped in this way can be part of tail cones of the embodiments in
It will be noted that the presence of additional access hatches in the flat bulkhead makes it possible to reduce the dimensions of the lateral hatches situated on the two sides of the fuselage.
The embodiment in
An upper aerodynamic cowl 120 and a lower aerodynamic cowl 122 extend from the upper edge and lower edge, respectively, of the panel 104, meeting the fuselage so as to reduce the parasitic drag produced by outward projections of the sliding panel at the rails 106a and 106b.
According to a variant that is not shown, one of the two lateral hatches in
According to another variant that is not shown, one of the two lateral hatches in
This difference in mounting makes it possible to modify the position of the hatches, in particular in terms of height.
It will be noted that the number of hatches shown in the various embodiments can vary, in particular be increased or reduced, depending on the application.
Although the lateral hatches and those (optional) in the flat pressure bulkhead have been described in relation to a tail cone of an aircraft with aft-mounted engines, any type of aircraft can be equipped therewith.
Any type of aircraft engine is suitable, namely a turboprop engine, a turbojet engine, an unducted engine with contrarotating fans, etc.
While at least one exemplary embodiment of the present invention(s) is disclosed herein, it should be understood that modifications, substitutions and alternatives may be apparent to one of ordinary skill in the art and can be made without departing from the scope of this disclosure. This disclosure is intended to cover any adaptations or variations of the exemplary embodiment(s). In addition, in this disclosure, the terms “comprise” or “comprising” do not exclude other elements or steps, the terms “a” or “one” do not exclude a plural number, and the term “or” means either or both. Furthermore, characteristics or steps which have been described may also be used in combination with other characteristics or steps and in any order unless the disclosure or context suggests otherwise. This disclosure hereby incorporates by reference the complete disclosure of any patent or application from which it claims benefit or priority.
Number | Date | Country | Kind |
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1551014 | Feb 2015 | FR | national |