GB2203105A

GB2203105A - Wing mounted ducted fan gas turbine powerplant

Info

Publication number: GB2203105A
Application number: GB08801275A
Authority: GB
Inventors: John Albert Mullins
Original assignee: Rolls Royce PLC
Current assignee: Rolls Royce PLC
Priority date: 1987-04-06
Filing date: 1988-01-21
Publication date: 1988-10-12
Anticipated expiration: 2008-01-21
Also published as: GB8801275D0; GB2203105B

Abstract

A ducted fan gas turbine powerplant 10 is located in overlapping relationship with an aircraft wing 12 via a pylon 14. Deflector flaps 22 are provided in the overlapping portion of the powerplant, which are movable soils to cause deflection of fan air which is ejected from the ducted tan, onto the wing upper surface during take off and/or landing of an associated aircraft. The flaps 22 may have trim tabs 26. <IMAGE>

Description

WING MOUNTED DUCTED FAN GAS TURBINE POWERPLANT The present invention concerns a combination of an aircraft wing and a ducted fan gas turbine powerplant which is connected thereto.

It is well known that the upper surface of an aircraft wing must be maintained free of any protruding structure if the maximum lift is to be obtained during flight of an associated aircraft. It follows that if a powerplant is connected to a wing at a position higher than the wing upper surface, but close thereto, some lift effect will be lost locally. This is especially so wherein the actual position of the powerplant relative to the wing is such that at least the major portion of the adjacent wing chord extends well beyond the downstream end of the powerplant.

The arrangement does have an advantage in so far as it results in vastly increased ground clearance.

The present invention seeks to provide an improved combination of a ducted fan gas turbine powerplant and an aircraft wing.

Accordingly the present invention comprises in combination, an aircraft wing, a ducted fan gas turbine powerplant connected to said aircraft wing at a position wherein the downstream portion of said ducted fan gas turbine powerplant overlaps the leading portion of the wing and the lower portion of the fan duct exit plane is adjacent to the leading edge of the wing and means on said overlapping portion for selectively urging at least the airflow from.the lower portion of the fan exit plane onto the upper surface of the wing during operation of an associated aircraft.

The means may comprise a pair of deflector flaps which are pivotably, mounted, one each side of the overlapping portion of the powerplant so as to enable movement of the deflector flaps to and from attitudes with respect to the fan exit airflow which causes the fan exit airflow to converge on the upper surface of the wing and means for moving the deflector flaps.

Preferably, though not restrictively, the flaps are pivoted about an axis which is normal to the axis of rotation of the rotatable structure of the ducted fan gas turbine powerplant.

Alternatively, each flap includes a hinge connection along one side thereof, by which the flap is hingedly connected to fixed external structure downstream of the fan air exit plane and in a non fan air deflecting position, form part of the outer casing of the overlapping portion of the ducted fan gas turbine powerplant.

Preferably the deflector flaps include trim tabs on their downstream edges so as to enable fine adjustment of the fan exit airflow direction with respect to the wing upper surface.

The ducted fan gas turbine powerplant may be connected to the wing via a pylon.

The pylon may contain accessory drive units and a drive shaft provided whereby to connect the accessory drive units to a shaft of the ducted fan gas turbine powerplant.

The pylon may be offset relative to the axis of rotation of the rotatable portions of the ducted fan gas turbine powerplant.

The invention will mow be described, by way of example and with reference to the accompanying drawings in which: Fig 1 is a side elevation of a combination in accordance with an embodiment of the present invention.

Fig 2 is a reduced scale view in the direction of arrow 2 in Fig 1.

Fig 3 to 5 inclusive each depict alternative embodiments of the present invention.

Referring to Fig 1. A ducted fan gas turbine powerplant 10 is connected to the wing 12 of an aircraft via a pylon structure 14.

The connection is such that the powerplant 10 is higher than than the upper surface 16 of the wing 12, so that in operation, air which leaves the fan nozzle 18 passes there over, but not necessarily in contact in a manner which ensures desirable conditions in the vicinity of the connection of the pylon 14 thereto.

Whilst it is important to maintain the known, appropriate airflow over all of the wing during the entire flight of an associated aircraft, it is particularly important to ensure this during the take off and landing regime of the flight. To this end, the core gas generator 20 of the ducted fan gas turbine powerplant 10 is provided with a pair of diametrically opposed flaps 22 which are connected thereto via axes 24 for pivoting movement as described hereinafter.

During the cruise regime of an associated aircraft, the flaps 22 are aligned with the direction of flow of air which is expelled from the fan nozzle 18, so as to cause as little deflection of the air as is possible from that flow direction, since in the cruise regime, such airflow is satisfactory. On take off of the associated aircraft, the flaps 22 are pivoted, by any suitable known power means which are controlled, either directly or indirectly by the pilot, to an attitude reletive to the fan airflow, which will cause that portion of the fan air stream which strikes the undersides of the flaps 22, to be deflected at an acute angle to its normal direction of flow, onto the upper surface 16 of the wing 12.This reduces the tendency of the ambient airflow over the wing upper surface 16 to break away therefrom by suppressing the turbulence which is generated by the presence of the pylon 14.

Trim tabs 26 are provided so as to enable fine air flow angle adjustment.

Referring now to Fig 2. The deflector flaps 22 are shown in full lines in their inoperative ie. non deflecting positions and in pecked-lines in an operative position. The pylon 14 is seen to be offset from the axial centreline of the powerplant 10 and, incidentally, contains accessory drive units 28. A drive shaft 30 connects the accessory drive units via gearing 31 to a shaft 32 of the powerplant 10. This is also shown in Fig 1.

In Fig 3, the flaps 22 are mounted on the core generator 20 via pivot axis 34 adjacent their downstream ends. The upstream ends of the flaps 22 have location members 36 which slidingly engage in grooves 38 in- the casing of the core gas generator 20. In the embodiment of Fig 3 therefor, the flaps 22 are supported fore and aft.

Referring to Fig 4. The flaps 22 in the embodiment depicted therein, are connected to the casing of the core gas generator 20 via a hinge (not shown) along a side edge 40 of each flaps 22. In an inoperative position, the flaps 22 form -part of the casing of the core gas generator, but when operative, they pivot outwardly of the casing in the manner of door panels. A trim tab or toe 42 if desired, any be fitted to the downstream edge of each flap 22.

Fig 5. depicts the ducted fan gas turbine powerplant 10, supported from the upper surface of the wing 12 as described hereinbefore, except that the supporting pylon 14 is arranged centrally of the powerplant 10.

Claims

Claims:

1. In Combination an aircraft wing, a ducted fan gas turbine powerplant connected to said wing at a position wherein the down-stream portion of said ducted fan gas turbine powerplant overlaps the leading portion of said wing and the lower portion of the ducted fan exit plane is adjacent the leading edge of said wing and means on said overlapping portion for selectively urging the airflow from the lower portion of the fan duct exit plane onto the upper surface of the wing during operation of an associated aircraft.

2. The combination of claim 1 wherein the means comprises a pair of deflector flaps pivotally mounted, one each side of the overlapping portion of the powerplant so as to enable movement of the deflector flaps to and from attitudes with respect to the fan exit airflow which cause the fan exit airflow to converge on the upper surface of the wing and means for moving the deflector flaps.

3. The combination of claim 2 wherein the flaps are pivoted about an axis which is normal to the axis of rotation of the rotatable structure of the ducted fan gas turbine powerplant.

4. The combination of claim 2 wherein each deflector includes a hinge connection along one side thereof, by means of which each flap is hingedly connected to fixed external structure downstream of the fan air exit plane and in a non fan air deflecting position, form part of the outer casing of the overlapping portion of the ducted gas turbine powerplant.

5. The combination as claimed in any of claims 2 to 4 wherein the ducted fan gas turbine powerplant is connected via a pylon connected to the said wing.

6. The combination as claimed in claim 5 wherein said pylon encloses accessory drive units and a drive shaft which connect said units to a shaft of the ducted fan gas turbine powerplant.

7. The combination as claimed in claim 5 or claim 6 wherein said pylon is offset relative to the axis of rotation of the rotatable structure of the ducted fan gas turbine powerplant.

8. The combination of an aircraft wing and a ducted fan gas turbine engine substantially as described in this specification and with reference to the drawings.