Cradle for a turbopropeller engine with integrated air inlet duct

Abstract

The invention relates to a cradle (10) for an aircraft turbopropeller engine (12) of a substantially axial orientation, comprising a front arch (16) and a rear arch (18) extending transversely relative to said axial direction (A), said arches (16, 18) being open at their lower ends and connected to each other by at least one axial longeron (34) extending between said arches (16, 18), characterised in that the longeron (34) is arranged in an upper portion of the cradle (10) and is formed in a single piece with the front arch (16).

Claims

1. A cradle for a turboprop engine of an aircraft oriented in a substantially axial direction, comprising a front arch and a rear arch extending transversally with respect to said axial direction, said arches being open at their lower ends and connected to one another by at least one axial longeron that extends between said arches, wherein the longeron is arranged in the upper portion of the cradle and said longeron is monolithic with the front arch, and with at least one tubular section configured to define an air inlet duct of said turboprop engine.

2. The cradle according to claim 1, wherein the longeron is further formed of one single part with at least a part of a pipe forming a particulate trap.

3. The cradle according to claim 1, wherein the tubular section comprises an air inlet that substantially opens onto a transversal plane of said front arch.

4. The cradle according to claim 1, wherein the tubular section comprises an air outlet that opens into said cradle along a plane substantially perpendicular to the plane of the air inlet.

5. The cradle according to claim 1, wherein the cradle has two lateral rods secured on either side of the upper portions of at least one of said arches, exclusive of any other rod.

6. The cradle according to claim 2, wherein said pipe forming the particulate trap comprises a front end that opens into the tubular section and at least one tubular and right-angled rear end, oriented outwards from the cradle and oriented along a substantially horizontal axis.

7. The cradle according to claim 1, wherein said cradle further has two longitudinal lateral walls, monolithic with the longeron, said longitudinal lateral walls extending towards the rear from the front arch and running along the entire length of the longeron.

8. The cradle according to claim 7, wherein the free longitudinal edges of the longitudinal lateral walls are configured to receive hinges for lateral protection hoods of the turboprop engine.

9. An aircraft turboprop engine unit, including a turboprop engine secured to a cradle according to claim 8, and wherein the turboprop engine comprises: a reduction gear that extends to the front of the front arch of said cradle and under the air inlet of the tubular section of the cradle, an air supply of said aircraft turboprop engine unit secured to said air inlet of the cradle, at least one item of equipment of the turboprop engine, secured under said turboprop engine, two beetle-wing hoods, each hinged on an edge of the longitudinal side walls of the cradle, which are joined in a closed position along a longitudinal line (D) arranged under the cradle.

10. The aircraft turboprop engine unit according to claim 9, wherein the beetle-wing hoods are structural hoods that contribute to rigidifying said power unit.

Description

BRIEF DESCRIPTION OF THE FIGURES

(1) The invention will be better understood, and other details, characteristics and advantages of the present invention will become clearer upon reading the following description, provided as an example and not limited thereto, and with reference to the appended drawings, wherein:

(2) FIG. 1 (already discussed) is a perspective view of a cradle according to the prior art attached under the wing of an aircraft and receiving a turbopropeller engine;

(3) FIG. 2 (already discussed) is a schematic transversal cross-sectional view of the cradle and turbopropeller engine of FIG. 1;

(4) FIG. 3 is a schematic cross-sectional view, along a transversal plane, of a turbopropeller engine received in a cradle manufactured according to the invention;

(5) FIG. 4 is a schematic perspective view of a turbopropeller engine received in the cradle manufactured according to the invention;

(6) FIG. 5 is a schematic transversal cross-sectional view along plane P of FIG. 3 of the cradle and the turbopropeller engine of FIGS. 3 and 4;

(7) FIGS. 6 to 8 are perspective views of a single-block unit comprising the upper longeron, the front arch, the tube section of the air inlet duct, and the particulate trap implemented in a cradle according to the invention.

DESCRIPTION OF AN EMBODIMENT OF THE INVENTION

(8) As shown in FIG. 4, the cradle 10 according to the invention comprises, similarly to the cradles known from the state of the art, a front arch 16 and a rear arch 18 open at the lower ends thereof and having in particular the shape of an inverted U, extending axially with respect to said axial direction A of the turbopropeller engine 12. The arches 16, 18 are connected by a truss 20 of rods.

(9) As is already known from the state of the art, the front 16 and rear 18 arches are connected by at least one axial longeron 34 extending between said arches 16, 18.

(10) According to the invention, the longeron 34 is advantageously arranged in the upper portion of the cradle and is formed of one single part with the front arch 16. This type of longeron significantly contributes to the rigidity of the cradle.

(11) In addition, the longeron 34 is advantageously formed of one single part with at least one tubular section 36 configured to define an air inlet duct 28 of said turbopropeller engine.

(12) This configuration is more specifically shown in FIGS. 6 to 8.

(13) In the preferred embodiment of the invention, the tube section 36 does not define the entire air inlet duct 26, but only part thereof, as will be seen below in the present description.

(14) Thus, the cradle 10 comprises one single and same part forming, as a minimum, the front arch 16, the longeron 34 and the tube section 36. This part can be produced by the moulding of a metallic material, or by means of mechanically welded construction. The rear arch 18 is provided on this unit, and more particularly at the rear of the longeron 34, as shown in FIG. 4. The truss 20 of rods is then provided on the cradle 10 so as to be secured, on the one hand, to the rear arch 18, and on the other hand, to the unit made of the longeron 34 the front arch 16 and the tube section 36.

(15) Advantageously, the longeron 34 is further formed of one single part with at least one part of the pipe 40 forming the particulate trap.

(16) As shown in FIGS. 6 to 8, the tube section 36 is preferably arranged under the longeron 34. When the unit formed of the longeron 34, the front arch 16 and the tube section 36 is made by moulding, an inner wall 42 of the tube section 36 is joined to a front portion of the longeron 34.

(17) As shown in FIG. 6, the tube section 36 comprises an air inlet 44 that substantially opens onto a transversal plane P of said front arch 16. Moreover, in the preferred embodiment of the invention, each arch 16, 18 has the shape of an inverted U, in order to enable a higher extraction of the turbopropeller engine 12 by lowering it from the cradle 10. Therefore, the air inlet 44 can preferably be arranged in a concave recess of the front arch 16, by form-fitting.

(18) It will be noted that the invention is not limited to this configuration, and that the air inlet 44 could also not be form-fitted with the concave recess of the front arch 16, or open onto a front face of a transversal arm of the front arch 16.

(19) As has been seen, the tube section 36 does not form the entire air inlet duct 26. As shown in FIG. 3, an air supply 46 comprising, at the end thereof an air intake 28, is provided on the front of the front arch 16, so as to coincide with the inlet 44 and to be interposed axially between this arch 16 and the propeller 30 of the turbopropeller engine 12.

(20) Moreover, the tube section 36 comprises an air outlet 48 that opens inside said cradle 10 in a plane P substantially perpendicular to the plane P of the air inlet 44, i.e. in a substantially horizontal plane P. As shown in FIG. 3, this air outlet 48 is intended to connect to an air inlet (not shown) of a compressor of the turbopropeller engine 12 to supply the latter with air. Thus, the inner wall 42 of the tube section 36 substantially forms a right angle between the air inlet 44 thereof and the air outlet 48 thereof.

(21) The pipe 40 forming the particulate trap is, as has been seen, connected to the tube section 36, since the purpose thereof is to trap particles contained in the air suctioned by the air inlet duct to prevent them from being suctioned by the compressor of the turbopropeller engine 12.

(22) To this end, the pipe 40 is connected to the inner wall 42 of the tube section 36. In particular, the pipe 40 comprises, as seen in FIGS. 7 and 8, a front end 50 that opens into the tube section 42 and at least one tubular and right-angled rear end 52, oriented outwards from the cradle 10 and oriented along a substantially horizontal axis C. Preferably, as shown in FIG. 7, the front end 50 of the pipe 40 is connected to two symmetrical tubular right-angled rear ends 52, each oriented laterally and outwards from the cradle, along two axes C that form an angle of less than 90 with the axial direction A of the turbopropeller engine 12, in order to allow the evacuation of foreign bodies and water filtered from the air flow surrounding the turbopropeller engine 12 during the forward motion of the aircraft.

(23) This arrangement in the upper portion of the cradle 10 of the tube section 36 delimiting the air inlet duct 28 and the pipe 40 forming the particulate trap is particularly advantageous, as it allows, with respect to a conventional cradle 10, to move these elements to the upper portion of the cradle 10, where they are less likely to absorb foreign bodies and/or stagnating water present on the surface of the ground. Consequently, the filtering of the air supplying the turbopropeller engine 12 is significantly improved. Furthermore, this configuration frees up the lower portion of the cradle 10 from these elements, which facilitates access to the turbopropeller engine 12 for maintenance or disassembly operations.

(24) Moreover, as shown in FIG. 5, the lower portion of the turbopropeller engine 12, no longer containing the air inlet duct 26 and the particulate trap, is able to receive the accessory gear box 32 in the lower part of the cradle 10, where it is no longer subject to an accumulation of hot air. This configuration improves the cooling of the members contained in this accessory gear box 32, such as an alternator and a starter of the turbopropeller engine 12, these members being particularly sensitive to heat.

(25) Moreover, as is shown in FIGS. 6 to 8, the cradle 10 comprises two longitudinal lateral walls 54, formed of one single part with the longeron 34, these walls extending towards the rear from the front arch 16 and running along the entire length thereof of the longeron 34.

(26) These walls 54 are connected to the unit formed by the longeron 34 of the front arch 16 and the tube section 36. Preferably, when this unit is moulded, the walls 54 are also made during the moulding operation. Advantageously, as seen in FIG. 5, the free longitudinal edges 56 of these lateral longitudinal walls 54 are configured to receive hinges 58 for the lateral protection hoods 60 of the turbopropeller engine 12, which delimit a nacelle of the turbopropeller engine 12. The hoods 60 are articulated around these hinges 58 so as to be able to be opened in a beetle-wing configuration as shown by the dotted lines in FIG. 5 relating to the hood 60 on the left side of FIG. 5, or be joined in a closed position along a longitudinal line D arranged under the cradle 10, as shown by a continuous line in FIG. 5.

(27) Such beetle-wing hoods 60, i.e. articulated along two close or similar parallel axes formed by the hinges 58, like the forewings of a beetle, are well-known from the state of the art.

(28) However, the lateral protection hoods 60 are, in this case, structural hoods that contribute to the rigidity of the unit formed by the cradle 10 and the hoods 60.

(29) With respect to a cradle known from the state of the art, the cradle 10 equipped with structural hoods 60 proposed herein has increased rigidity. Therefore, it can comprise a truss 20 of rods comprising a limited number of rods, and in particular no longer comprising rods in the lower portion. Thus, as shown in FIGS. 4 and 5, the truss 20 of rods only comprises the upper lateral rods 22 secured on either side of the upper ends of said arches 16, 18, exclusive of any other rod. This configuration significantly facilitates accessibility to the lower portion of the cradle 10, and therefore the accessibility to the turbopropeller engine 12.

(30) The cradle 10 according to the invention is therefore particularly well adapted to an aircraft power unit comprising a turbopropeller engine attached to the cradle 10 and provided with a reduction gear 31 extending at the front of the front arch 16 of said cradle 10 and under the air inlet 44 of the tube section 36, as shown in FIG. 3. In this power unit, this air inlet 44 is supplied by an air supply 46 comprising at the end thereof an air intake 28 and interposed between the front arch 16 and the propeller 30. Such a power unit can easily undergo maintenance operations relating to elements of the turbopropeller engine 12 thereof, since the equipment such as the accessory gear box 32 of the turbopropeller engine 12 can be easily disassembled and does not impede the access to the lower portion of the turbopropeller engine 12, which makes it possible for direct interventions on the turbopropeller engine 12 or the easy extraction thereof from the cradle 10.