Lift-generating device having axial fan(s), and heavier-than-air aircraft fitted with such a device

• US 9,694,907 B2
• Filed: 07/03/2014
• Issued: 07/04/2017
• Est. Priority Date: 07/12/2013
• Status: Active Grant

• Current Assignee: Hutchinson (Welltower, Inc.)
• Original Assignee: Hutchinson (Welltower, Inc.)
• Inventors: Andre, Sbastien, Simon, Jean-Michel, Dominiak, Christophe
• Primary Examiner(s): Ellis, Christopher P
• Application Number:
  US14/904,597
• Publication Number:
  US 20160152333A1
• Time in Patent Office: 1,097 Days
• Field of Search: 244 23 B, 244 7 R, 244 6, 244 23 A, 244 45 R, 244 39
• CPC Class Codes: B64C 29/0025 the propellers being fixed relative to the fuselage

Abstract

The invention relates to a device which includes two longitudinal deflecting surfaces or two pluralities of longitudinal deflecting surfaces, which are symmetrical on either side of the plane formed by the roll and yaw axes of the device and substantially in line with the roll axis and parallel to same, an air flow generator including at least one axial fan suctioning ambient air by means of at least one propeller faired in a flow path and, downstream of said propeller, an air distributor-diffuser, consisting of two adjacent semi-distributors each defining a curved duct directing the air to an outlet opening and toward the longitudinal deflecting surface or plurality of longitudinal deflecting surfaces.

Claims

1. A lift-generating device for a vertical- or short-takeoff heavier-than-air aircraft, using the lift-generating effect obtained by blowing a majority of an air flow produced by an air flow generator over deflecting surfaces linked to a load-bearing structure, the device comprising two longitudinal deflecting surfaces, arranged on either side of a roll axis of the device and extending substantially parallel with said roll axis, said two longitudinal deflecting surfaces being symmetrical with one another with respect to a plane defined by said roll axis and a yaw axis of the device, said air flow generator comprising at least two axial fans having axes which are substantially parallel with said yaw axis, and mutually offset on said roll axis, said axial fans being mounted in said load-bearing structure, and each drawing ambient air via a respective intake opening arranged in an upper face of said load-bearing structure, using at least one multi-blade rotor driven in rotation about an axis of a corresponding axial fan and faired in a flow path with a circular cross-section extending said inlet opening towards an inside of said load-bearing structure, wherein said at least two axial fans each comprise at least two stages having pluralities of blades, one of which is said multi-blade rotor mobile in rotation about the corresponding axis, and the lift-generating device comprises, downstream of each of said at least two axial fans, an air distributer-diffuser, consisting of two adjacent semi-distributors, symmetrical with one another with respect to a plane defined by said axis of said corresponding axial fan and said roll axis, each semi-distributor delimiting a curved duct having an inlet opening receiving one of two halves of the air flow leaving said corresponding axial fan, on a side of respectively one of said two longitudinal deflecting surfaces, and guiding the air that passes through said curved duct to an outlet opening incorporated in respectively one of two lateral faces of said load-bearing structure by means of a plurality of channels extending at least over a portion of a length of said curved duct and delimited by deflecting partitions formed by generatrices parallel with said roll axis, and towards said longitudinal deflecting surface situated on a same side as said semi-distributor, so that an air flow drawn in by each said axial fan is divided into two halves, the majority of each of which is laterally blown over respectively one of said two longitudinal deflecting surfaces.

2. The device according to claim 1, comprising successively, from a front to a rear of said load-bearing structure, and centred in a plane of symmetry defined by said roll and yaw axes of the device, a series of said at least two axial fans each cooperating with an air distributor-diffuser, followed or preceded by at least one axial fan with an axial flow outlet, the flow of which passes through said load-bearing structure from top to bottom.

3. The device according to claim 2, wherein said axial fan with an axial flow outlet has an axis parallel with said yaw axis and has an outlet section situated in the vertical extension of an inlet section, with a ratio between said outlet section and said inlet section that is greater than 1.

4. The device according to claim 2, wherein at least one axial fan is fitted with a least one propeller having variable-pitch and adjustable blades, and driven in rotation at a constant nominal speed.

5. The device according to claim 4, wherein all said axial fans are driven by a drive system with fixed drive ratios, and a thrust of at least one axial fan with variable-pitch propeller is adjustable by controlling the pitch, in order to contribute to balancing the attitude of the device.

6. The device according to claim 1, wherein an air flow generated by each axial fan with air distributor-diffuser is directed to each side of said load-bearing structure with an outward angular orientation, an angle between the direction of said flow and a plane defined by said roll and yaw axes of the device being situated between 5°

and 20°

.

7. The device according to claim 1, wherein a radius of at least one axial fan with air distributor-diffuser is greater than a distance between a low point of said outlet opening of said air flow of said air distributor-diffuser, and a median plane of symmetry of the device, defined by said roll and yaw axes of the device.

8. The device according to claim 1, wherein at least one portion of said longitudinal deflecting surfaces extends longitudinally in a substantially parallel fashion to said roll axis over a length greater than or equal to the sum of diameters of said fans with distributor-diffuser.

9. The device according to claim 1, wherein at least one axial fan comprises two multi-blade rotors that are coaxial and contra-rotating about a common axis.

10. The device according to claim 1, wherein on at least one axial fan with distributor-diffuser, a flow rectifier is mounted between said at least one multi-blade rotor and said air distributor-diffuser, said rectifier including a plurality of fixed vanes, which rectify an air flow at said outlet of said fan substantially parallel with said axis of said axial fan, said fixed vanes extending radially between an annular hub through which at least one drive shaft of said at least one multi-blade rotor passes, and a circular peripheral rim, coaxial with said annular hub about said axis of said fan and fixed to said load-bearing structure.

11. The device according to claim 1, wherein, on at least one axial fan with distributor-diffuser, a flow distributor-deflector is mounted upstream, above said at least one multi-blade rotor, said flow distributor-deflector including a plurality of radial fixed vanes, which deflect an air flow at an inlet of said axial fan so that the sum of deflected flows due to the presence of said distributor-deflector and said at least one multi-blade rotor is substantially zero so that the air flow has an orientation substantially parallel with said axis of said axial fan, at said outlet of said axial fan.

12. The device according to claim 1, wherein an area of the cross-section of said curved duct, perpendicular to a local direction of flow of air in said curved duct, is substantially constant so that a ratio of said area of the cross-section of said outlet opening to an area of the section of said inlet opening is comprised between substantially 1 and substantially 2.

13. The device according to claim 1, wherein a shape of the cross-section of said curved duct develops progressively from a semi-circular shape at said inlet opening, in a plane substantially perpendicular to said axis of the corresponding fan, to a substantially ovoid shape in a direction substantially parallel with said roll axis, at said outlet opening, in a plane substantially parallel with said axis of said fan on said axis of said fan.

14. The device according to claim 1, wherein a shape of said outlet opening of said curved duct is substantially rectangular.

15. The device according to claim 1, wherein said curved duct is made up, between a semi-circular inlet opening and said outlet opening, of a curved upstream portion the cross-sections of which are substantially semi-elliptical, and comprising said plurality of deflecting partitions for guiding the air flow passing through said duct, and a downstream portion, without a deflecting partition, and substantially straight between a last, substantially semi-elliptical section, of said upstream portion and said outlet opening.

16. The device according to claim 1, wherein said two longitudinal deflecting surfaces are longitudinal lift-generating aerofoils fixed laterally outside said load-bearing structure and each facing said outlet opening of said curved duct of respectively one of said two semi-distributors so that a majority of the air flow passing through said curved duct is blown over a facing one of said longitudinal aerofoils, which delivers a lift transmitted to said load-bearing structure.

17. The device according to claim 16, wherein said curved duct has cross-sections the shape of which develops progressively, from said semi-circular inlet opening, in semi-ellipses elongated along their long axis, which is parallel with said roll axis, to a semi-ellipse of longer axis at said outlet opening.

18. The device according to claim 17, wherein said long axis of said semi-ellipse of said outlet opening is comprised substantially between 1.2D and 1.5D, where D is the diameter of the section of said inlet opening.

19. The device according to claim 16, wherein said outlet opening of said curved duct opens out at the level of blow vents arranged in a longitudinal side of said load-bearing structure opposite said facing one of said longitudinal aerofoils.

20. The device according to claim 19, wherein streamlined ribs with a cross-section in the shape of a wedge extend along at least one of upper and lower edges of said blow vents of said longitudinal aerofoils and project towards said aerofoils so as to draw ambient air through a lateral blow flow outlet via said vents and dilute said flow, while reducing the pressure losses at an outlet of the vents.

21. The device according to claim 19, wherein the outlet flow from said vents is inclined downwards, with respect to a plane perpendicular to said axis of said fan, at an angle comprised between 0°

and approximately 60°

.

22. The device according to claim 19, wherein each of said longitudinal aerofoils is made up of a longitudinal wing having a leading edge which is immediately adjacent to said lower edge of said blow vents in a corresponding longitudinal side of said load-bearing structure, so as to blow over an upper surface of said longitudinal aerofoil and generate a Coand{hacek over (a)} effect lift.

23. The device according to claim 16, wherein each curved duct comprises a cloth sheath shaped by composite stiffeners in the form of battens, forming a sheath inlet frame with a semi-circular hoop, a sheath outlet frame substantially rectangular in shape, curved stiffeners being connected to said inlet and outlet frames and oriented in the direction of an air flow passing through said curved duct, and at least one curved deflecting partition defined by generatrices parallel with said roll axis.

24. The device according to claim 1, wherein said two longitudinal deflecting surfaces are aerodynamically profiled deflecting vanes, mounted at least partially inside said curved ducts of said semi-distributors downstream of said deflecting partitions, said deflecting vanes being defined by generatrices parallel with said roll axis, curved and having their concavity facing downwards and inwards, on the side of said load-bearing structure, so as to deflect an air flows passing through said curved ducts downwards, in order to generate a lift force on said load-bearing structure by reaction.

25. The device according to claim 24, wherein said curved ducts, partitions and curved deflecting vanes are arranged and dimensioned so that a majority of each half-flow from each corresponding fan is laterally offset with respect to said roll axis, by a distance greater than or equal to the radius of said fan.

26. The device according to claim 24, wherein a longitudinal deflecting vane is associated with said curved ducts of said semi-distributors which are on a same side of said load-bearing structure, an upstream portion of said deflecting vane being engaged inside an outlet manifold common to all said curved ducts of said same side, downstream of said deflecting partitions, and a downstream portion of said deflecting vane projecting outside said outlet manifold and oriented substantially downwards.

27. The device according to claim 24, wherein a plurality of longitudinal deflecting vanes, spaced apart and offset from one another respectively from the outside in and from top to bottom with respect to said load-bearing structure, is associated with said curved ducts of said semi-distributors which are on a same side of said load-bearing structure, and totally engaged inside an outlet manifold common to all said curved ducts of said same side, downstream of said deflecting partitions, substantially from the outlet end of said manifold in which said downstream ends of said vanes are substantially arranged.

28. The device according to claim 26, wherein at least one longitudinal deflecting vane is pivotably mounted about at least one longitudinal axis substantially parallel with said roll axis, between two end positions, one of which is an operating position, in which an air flow passing through said corresponding curved ducts is deflected downwards, and a closed position of said outlet opening of said curved ducts for cruising flight.

29. The device according to claim 1, wherein a diameter of said fans parallel with said pitch axis extends over a majority of a width of said load-bearing structure, and is more than 80% of said width.

30. The device according to claim 1, wherein vibrating membrane strips are arranged parallel with said roll axis on an upper surface of one at least of said deflecting partitions and said deflecting surfaces so as to reduce turbulence of an air flow passing over at least one of said deflecting partitions and said deflecting surfaces.

31. The device according to claim 1, wherein, on the one hand, a cross-section of each individual channel delimited by two successive deflecting partitions remains substantially constant over the whole length of said channel, while an air flow passes through the area of said partitions, and that, on the other hand, the ratio of each cross-section of an individual channel to a lateral surface of said individual channel remains substantially equivalent between all said channels delimited by said partitions.

32. The device according to claim 1, wherein at least one closing cover is mounted on an upper portion of said load-bearing structure, moveable between two positions, an open position in which at least one fan is open in vertical flight configuration, and a closed position of said at least one fan, in which said cover covers said at least one fan for cruising flight.

33. The device according to claim 1, wherein a continuous volume, at least partially dedicated to a payload, is arranged at least below and between said at least two axial fans with air distributor-diffuser.

34. A vertical- or short-take-off and landing heavier-than-air aircraft comprising a load-bearing structure supporting a lift-generating device comprising two longitudinal deflecting surfaces, arranged on either side of a roll axis of the device and extending substantially parallel with said roll axis, said two longitudinal deflecting surfaces being symmetrical with one another with respect to a plane defined by said roll axis and a yaw axis of the device, said air flow generator comprising at least two axial fans having axes which are substantially parallel with said yaw axis, and mutually offset on said roll axis, said axial fans being mounted in said load-bearing structure, and each drawing ambient air via a respective intake opening arranged in an upper face of said load-bearing structure, using at least one multi-blade rotor driven in rotation about an axis of a corresponding axial fan and faired in a flow path with a circular cross-section extending said inlet opening towards an inside of said load-bearing structure, wherein said at least two axial fans each comprise at least two stages having pluralities of blades, one of which is said multi-blade rotor mobile in rotation about the corresponding axis, and the lift-generating device comprises, downstream of each of said at least two axial fans, an air distributer-diffuser, consisting of two adjacent semi-distributors, symmetrical with one another with respect to a plane defined by said axis of said corresponding axial fan and said roll axis, each semi-distributor delimiting a curved duct having an inlet opening receiving one of two halves of the air flow leaving said corresponding axial fan, on a side of respectively one of said two longitudinal deflecting surfaces and guiding the air that passes through said curved duct to an outlet opening incorporated in respectively one of two lateral faces of said load-bearing structure by means of a plurality of channels extending at least over a portion of a length of said curved duct and delimited by deflecting partitions formed by generatrices parallel with said roll axis, and towards said longitudinal deflecting surface situated on a same side as said semi-distributor, so that an air flow drawn in by each said axial fan is divided into two halves, the majority of each of which is laterally blown over respectively one of said two longitudinal deflecting surfaces.

35. The heavier-than-air aircraft according to claim 34, wherein said device is supported in an upper portion of said load-bearing structure, which is arranged in a lower portion as a nacelle housing an engine and supporting at least one of a transverse, triangular or delta front aerofoil, a rear aerofoil and an aerofoil that is arranged between said two longitudinal deflecting surfaces or pluralities of surfaces of said device.

36. The heavier-than-air aircraft according to claim 34, wherein said device is supported in an upper portion of said load-bearing structure, which is arranged in a lower portion as a nacelle housing an engine and supporting at least one wing extending in the lateral extension of said load-bearing structure and immediately above said lateral outlet openings of said curved ducts of said air distributor-diffusers.

37. The heavier-than-air aircraft according to claim 34, comprising a number of fans mainly fitted with contra-rotating propellers and without a flow rectifier.