GB2089745A - Thrust deflector - Google Patents

Abstract

To simplify gas turbine engine construction, thrust deflecting mechanisms are provided in aircraft structure. The arrangement herein uses upper and lower panels (24, 28) cut out of the wing (12) and remounted on pivots carried below the wing by sidewalls (16), the deflecting mechanism being located behind a pylon-mounted engine (10). When deployed, the mechanism turns the jet through the cutout (18) and over the wing upper surface. <IMAGE>

Description

SPECIFICATION Thrust deflector This invention relates to thrust deflectors which are suitable for use in the braking of gas turbine engine powered aircraft.

Thrust deflectors are in common use on gas turbine engines including those gas turbine engines which have ducted fans. Flaps which may form part of a gas or air flow surface when non operative, are moved across the gas or air flow and in so doing, open lateral gaps in the engine cowling through which the gas or air is deflected by the flaps.

A drawback of powerplant mounted deflector flaps, is that as the desired flow characteristics of the powerplant dictate the profile of the powerplant, so they dictate the shapes of the flaps and, more particularly the equipment ancillary to their operation, with the result that the resulting design is complicated and requires many moving parts. There also normally results, an undesirably heavy assembly.

There has been mooted, the idea of separating of the thrust deflecting apparatus from the power plant so as to enable a more simple structure to be achieved. One example of such an arrangement is disclosed in published British Patent specification 1,088,153. A further example is disclosed in British early published patent application 7921019. Each of the examples disclose deflection structure which is cantilevered to structure which is fixed to, or forms part of the aircraft, with the result that unsupported large surface areas, are necessarily exposed to the thrust from a powerplant.

The present invention seeks to provide an improved thrust deflecting structure comprising an aircraft wing having means for supporting a gas turbine engine therefrom and including a cutout in its trailing edge which cutout is aligned with said engine suporting means, in a direction chordally of said wing, said cutout being closed with an upper wing panel and a lower wing panel underlying said upper wing panel, which panels are adapted so as to move relative to each other in a substantially vertical plane to achieve respective positions wherein in opertion, the lower wing panel deflects engine efflux upwardly and the upper wing panel deflects the upwardly deflected engine efflux forwardly and wherein at least the greater part of each panel projects beyond one outer surface of said wing and expose said cutout and means for achieving said relative movement.

The invention will now be described by way of example and with reference to the accompanying drawings in which: Figure 1 is a pictorial view of a wing supporting a gas turbine engine and embodying deflectors in accordance with the invention, Figure2 is an enlarged partviewof Figure 1, Figure 3 is as Figure 2 but with deflectors partically deployed, Figure 4 is as Figure 2 but the deflectors fully deployed, Figure 5 is a pictorial part view of the wing of Figure 1, Figure 6 is a pictorial part view of the wing of Figure 1.

Figures 7 and 8 are cross-sectional part views of an alternative embodiment of the invention.

In Figure 1 a gas turbine engine 10, which in the present example includes a ducted fan, is supported from an aircraft wing 12 by a pylon 14.

Wing 12 has a pair of hollow sidewalls 16 of which only one can be seen in Figure 1. Sidewalls 16 project downwardly and rearwardly from the under sideofwing 12.

Referring now to Figure 2. Wing 12 has a rectangular cutout indicated generally by numeral 18, in its trailing edge portion. Cutout 18 extends forwardly into wing 12 and its upstream boundary is defined by wall 20. Its downstream boundary defines a portion of the wing trailing edge 22. The side boundaries of the cutout 18 are defined by sidewalls 16.

It should be noted that the terms "upstream" and "downstream" refer to the direction of airflow over wing 12 during flight of an associated aircraft.

Cutout 18 is filled by an upper wing panel 24 which has its own side walls 26 nesting within sidewalls 16 and, a lower wing panel 28 which also has is own side walls 30 nesting within side walls 26.

Both wing panels 24 and 28 are pivotally connected to side walls 16 for pivotal movement abut a common axis 32. Pivotal movement is brought about by respective pairs of screw jack mechanisms 34,36 of which only one of each is shown.

Screw jack mechanism 34 comprises of a screwed shaft 34a pivotally connected via one end 38 to and within sidewall 16. Shaft 34a is in screw threaded engagement with a ball nut 40 supported at a fixed location on the sidewall 26 of panel 24, but projects through an arcuate slot 42 in sidewall 16 into its hollow interior, so as to receive screwed shaft 34a.

The radii of arcs which define slot 42, are struck about axis 32.

Screw jack mechanism 36 is similar in construction to that of screw jack mechanism 34. Screwed shafts 36a is pivotally connected to sidewall 16 for pivotal movement about an axis 46. Its associated ball nut 48 is attached to the sidewall 30 of panel 28 and an arcuate slot 50 is provided in the edge of sidewall 16, to allow exit and entry of the ball screw, as panel 28 is pivoted to and from an operative position. It will be appreciated by the skilled man, that ball nuts 40, 48 must be pivotably attached in their fixed locations, so as to enable their respective screw shafts to adopt differing attitudes as panels 24 and 28 pivot. Moreover, the skilled man will appreciate that fluid powered rams may be used in substitution for screw jack mechanisms 34 and 36.

Pivoting of panels 24 and 28 is brought about by effecting relative rotation between screw shafts 34a and 36a and their respective ball nuts 40 and 48. Any suitable known means e.g. flexible drive transmission, (not shown) may be used to achieve the relative rotation, for screw jack mechanisms and their operation are well known in the art.

Referring to Figure 3. Panels 24 and 28 are partially deployed, as a result of screw jack mechanism 34 and 36 being actuated.

In Figure 4, panels 24 and 28 are fully deployed and have adopted a position in which the majority of their volume is below the upper surface of wing 12 and in which they cooperate in overlapping manner to form a scoop.

When in the Figure 4 position, the panel 28 lies across the mixed flow of exhaust gases and fan air from engine 10 (as seen in Figure 5) and deflects the mixed flow upwardly through the cutout 18 which has been exposed on movement of panels 24 and 28 to their operative positions.

Panel 24 is at an attitude in which it forms the downstream boundary of cutout 18 and results in the upwardly deflected flow being given a forward component of movement, and so provides some reverse thrust The forwardly deflected flow also tends to detach the ambient air flow over the wing, from the wing upper surface and so provides a lift dumping effect.

Referring to Figure 5. Panel 24 and panel 28 which underlies it are shown in their inoperative positions as in Figure 1 and can. be seen to be aligned with gas tubine engine 10 in a direction chordally of wing 12.

In the new arrangement described therein, each thrust deflector 24, 28 is supported at both sides, about pivot axes 32, against the loads exerted therein by the gas flow.

Deflector 28 which effectively bears the full available thrust load from the nozzles of engine 10, is further supported via screw jack mechanisms 36 in that, should panel 28 experience a thrust load which is not passed through pivot axes 32, any tendency of panel 28 to turn under the load will be resisted along the axis of screw jack mechanism 36.

Referring now to Figure 7 in which like parts have like numerals, a further panel 70 nests between panels 24 and 28 and is movable so as to bridge the adjacent ends of panels 24 and 28. Movement of further panel 70 is achieved in the same manner as is the movement of panels 24 and 28.

All of the panels may be arranged in tracks (not shown) which would be formed in walls 16, thus obviating the need for pivot mounting about axis 32.

In such an arrangement i.e. track supported, the panels 24,28 and 70 would be moved in a manner similar to the moving of wing flaps as is known in the art.

Whilst the arrangement described hereinbefore refers to a wing which has an engine affixed thereunder, the invention may also be applied to a wing which supports an engine from and over its upper surface.

In such an arrangement, flaps 24 and 28 will be caused to pivot upwards and side walls 16 will project from the wing upper surface.

Claims (10)

1. Thrust deflecting structure comprising an air craft wing having means for supporting a gas turbine engine therefrom and including a cutout in its trailing edge which cutout is aligned with said engine supporting means, in a direction chordally of said wing, said cutout being closed with an upper wing panel and a lower wing panel underlying said upper wing panel, which panels are adapted so as to move relative to each other in a substantially vertical plane to achieve respective positions wherein in operation, the lower wing panel deflects the upwardly deflected engine effluxforwardly and wherein at least the greater part of each panel projects beyond one outer surface of said wing and expose said cutout and means for achieving said relative movement.

2. Thrust deflecting structure as claimed in claim 1 wherein said wing outer surface has a pair of sidewalls aligned chordally of the wing and said upper and lower wing panels are pivotally connected thereto via a common pivot means.

3. Thrust deflecting structure as claimed in claim 2 wherein said upper and lower wing panels have sidewalls which restwithin said wing outer surface sidewalls.

4. Thrust deflecting structure as claimed in any previous claim wherein said one wing outer surface is the wing underside.

5. Thrust deflecting structure as claimed in any previous claim wherein said upper wing panel and said lower wing panel overlap each other when in said respective positions.

6. Thrust deflecting structure as claimed in any of claims 1 to 4 including a further movable panel which in a non operative position, bridges the adjacent ends by said upper wing panel and said lower wing panel.

7. Thrust deflecting structure as claimed in any previous claim wherein the moving means comprises screw jack mechanisms connected between wing structure and respective panels.

8. Thrust deflecting structure as claimed in claim 6 wherein said further movable panel is connected to said lower wing panel for movement therewith.

9. Thrust deflecting structure substantially as described in this specification with reference to Figures 1 to 6 of the drawings.

10. Thrust deflecting structure substantially as described in this specification with reference to Figure 7 of the drawings.