GB2050262A - Method and mechanism for changing the wingplan geometry of aeroplanes in flight - Google Patents

Abstract

A method and mechanism for changing the wingplan geometry of the main wing of an aeroplane in flight. A slat (1) is pivotally mounted to the main wing (4) with its leading edge matching that of the main wing. By sliding the slat forward the slat is angularly projected over the wing leading edge to form an adjustable angle (a) thereby increasing the wing chord. Sliding the slat downwards creates a wing slot forming an angle (b) thereby changing the wing camber. These sliding operations collectively improve the aeroplane flight stability at low speeds on take-off and when landing. <IMAGE>

Description

SPECIFICATION Method and mechanism for changing thewingplan geometry of aeroplanes in flight The present invention relates to a system providing a means for adapting main wings of aeroplanes of the type having straight or sweptback wing arrangements. This system allows the wing plan and its aerofoil to be changed without interferring with the basic wing frame of the aeroplane and giving the wing system a better performance and greater safery at low speed without prejudicing the high speed flight conditions.

Several ways to create slots in the leading-edge of wings in order to control wing stall even with high angles of attack, and to increase lift and stability of the aeroplane at low speeds, are already well known to those skilled in the art. Such techniques are used largely during take-off and landing by a combination of the leading-edge slots and lowering of the trailing-edge flaps so as to modify the wing aerofoil.

So far, however, nothing has been proposed or embodied which allows the simultaneous adjust mentofthe aerofoil and change of the wing plan, so as to adjust the sweepback angle (namely, the angle between fuselage and wing leading edge) and the wing chord, to obtain both a substantial flight stabilization at high angles of attack (in take-off and landing) and to reduce operational speeds with increased safety.

According to the present invention there is provided a mechanism for changing in flight the wing plan geometry of an aeroplane having main wings in a straight or swept-back arrangement by producing wing slots, to increase the wing chord and/or change the wing aerofoil camber, the mechanism comprising: a slat for lengthwise pivotal mounting on the wing so as to match the shape of the leading edge of the wing and having slot actuating means; an electric motor for rotating an axle of the slat actuating means via mechanical transmission means, the axle being provided for location on the wingtip tranversely thereof to cause, via universal joints, forward and backward sliding of a threaded intermediary arm, which carries a forked member having a limb adapted to run in a guide rail provided to be mounted transversely on a wing rib, the forked member being adapted to be fixed on the free end of the slat opposite the end of the slat which is provided, the slat being angularly displaced by the pivotal means therefor formed by a vertical axle urged backwards by spring means and supported by a spherical bearing.

Thus, a slat, or leading-edge flap is provided which is pivotally mounted lengthwise over the leadingedge of the wing and actuated so as to obtain its angular displacement from the wing edge as well as its lowering to form an adjustable slot; the actuating mechanism being designed so as to allow its optional use in conjunction with the driving system of the trailing-edge flaps.

The mechanism of this invention can be easily and is preferably driven by automatic means to be actuated at pre-selected speeds, to obtain a simul- taneous or optional change of the wing camber, the increase of the wing-tip chord (decreasing toward the wing root) and to form an adjustable slot on the leading-edge of the wing, all of which being achieved through rotational movements instead of the translational movements applied up till now which, notwithstanding the sophisticated driving and control means being used, do not permit angular change between the wing leading-edge and the fuselage nor adjustable sweep back.As far as the possibility of variation in the wing sweepback is concerned, enormous advantages which derived from this invention should be evident to those skilled in the art such as, for example, an airplane pilot or aircraft manufacturer when compared with the known systemforvarying the wing geometry by pivoting the whole wing frame which demands the provision of a hinged structure by which the heavy wing rotates on a high precision and complicated hinging system.

Preferred embodiments of the present invention will be described by way of example with reference to the accompanying drawings, in which: Figure lisa schematic top plan view of a straight-wing arrangement of a main wing of an aeroplane at cruising flight speed; Figure 2 is the same view as in Figure 1 showing the wing geometry changed to high angles of attack; Figures 3 and 4 show schematic cross-sectional views along lines AA of Figures 1 and 2 showing the pivoted slat in the closed and open position respectively; Figure 5 shows in a schematic cross-sectional view along lines BB of Figure 2 forward sliding of the slat; Figure 6 shows schematically the sliding movement of the slat both foward and downward, optionally forming angle "b"with the wing chord; Figures 7, 8 and 9 show construction details of the slat guide rail;Figure 9 showing a cross-section view along the line M-M of Figures 5,6,7 and 8; Figure 10 is a schematic cross-sectional view along line C-C of Figure 1,2 and an enlarged prespective view of the slat displacing device.

Figure 11 shows a schematic view of a straightwing aeroplane showing the location of the transmission and displacing mechanism in the main wing; Figure 12 is a general perspective view of the whole mechanism assembled in the main wing of an aeroplane; Figures 13, 14 and 15 show schematic view of the changes obtained in the wingtip chord, the wing camber and the angle "a"made by the leading-edge of the wing with the fuselage of the airplane with sweptback arranged wings, and Figures 16 and 17 show schematic views of one alternative embodiment of this invention having two partially superimposed slats allowing a double-slot arrangement to be obtained and a greater increase in the wing chord adjustment.

in Figures 1 to 4, one straight main wing 4 of an aeroplane is illustrated. Slat 1 is pivotally mounted at 2 on the main wing 4 designed so as to match the wing leading-edge 4', angular movement of the slat 1 being achieved by means of actuating means 3 iocated on or close to the tip of the wing. The actuating means 3 can drive the slat 1 forward to provide an angular displacement "a", creating a slot 5 (Figure 4) and slide it downwards (Figure 6) to form an angle "b "allowing the desired change in the wing camber to be achieved.

In Figures 5 to 12 the construction and functioning of the actuating means 3 are illustrated. The actuating mechanism 3 is essentially composed of a drive shaft 7 supported along its length by several bearings 8 located along the length of a beam 6 of the wing structure and is driven by an electric motor 14 or any other available energy source, through meshing drive gears 9.

The rotation of the drive shaft 7 is transmitted by means of conical drive gears 9', to an axle 7' orthogonally supported by a bearing 8', the axle 7' ending in a universal joint 10 which actuates the threaded arm 11 which, through a second universal joint 12 moves a forked member 15 backwards and forwards. The forked member 15 is provided with a limb 15', which runs in a guide rail 13 placed transversely within the wing frame close to the wingtip (Figures 5, 6, 12) on a rib 6'.

The forked member 15 is attached to the free end of the slat 1, opposite the pivoted end. The guide rail may have a straight line path (Figure 5 and 7) or may follow a curved path (Figure 6 and 8) in conformity with the desired change in aerofoil camber for the wing and tilting degree to be imparted to the slat. At the pivotal site 2 of the slat 1, an adjustable mechanism is provided. This mechanism has one spherical bearing 16, whose vertical axle is pulled backwards by a helical spring 17', to the idle position with the slat 1 fully retracted. The axle 17 may turn through 360"C to form a solid angle (Figure 10), thereby allowing the forward and downward sliding movement of the slat 1, and is therefore attached at the pivoting extremity 2.

A bearing 18 is provided with an elongate central slot 18', to guide the movement of the axle 17 so as to follow the sliding of the slat to optionally form the angle "b"(Figures 6 and 12) and modify the aerofoil camber.

In Figures 13, 14 and 15 the results obtained by use of the device of this invention applied to aeroplanes having a sweptback wing arrangement are shown.

The slot 5 on the leading-edge 4' of the wing 4, changes the wing camber, as well as modifying the wing chord by sliding of the slat 1 to form the angle "a"(Figure 13).

Figures 16, 17 and 18 show schematically an alternative embodiment of this invention in which two superimposed slats 1, 1A, each of which are pivoted at separate points 2 and 2A so as to allow a greater range when changing the wing chord. By means of double slots 5 and 5A formed at the leading-edge, an increased sweepback manouvering of the wing is achieved giving more stability to the aeroplane at low speeds.

Claims (5)

1. A mechanism for changing in flightthe wing plan geometry of an aeroplane having main wings in a straight or sweptback arrangement by producing wing slots, to increase the wing chord and/or change the wing aerofoil camber, the mechanism comprising: a slat for lengthwise pivotal mounting on the wing so as to match the shape of the leading-edge of the wing and having slat actuating means; an electric motor for rotating an axle of the slat actuating means via mechanical transmission means, the axle being provided for location on the wingtip transversely thereof to cause, via universal joints, forward and backward sliding of a threaded intermediary arm, which carries a forked member having a limb adapted to run in a guide rail provided to be mounted transversely from a wing rib, the forked member being adapted to be fixed on the free end of the slat opposite the end of the slat which is pivoted, the slat being angularly displaced by the pivotal means therefor formed by a vertical axle urged backwards by spring means and supported by a spherical bearing.

2. A mechanism as claimed in claim 1, wherein the pivotal means are adapted to the inside of the middle wing section, the pendular rotative movement of the axle being guided by a support provided with a central slot for orientation transversely to the wing, allowing the axle to follow forward, backward and downward displacements of the pivoted slat and wherein the axle is fixed at the pivotal mounting points of the slat.

3. A mechanism as claimed in claim 1 or 2, wherein the transmission means comprises a rotary shaftjournaled on bearings for mounting along a longitudinal beam of the wing structure, meshing gears driven by the electric motor for rotating the rotary shaft, and conical gears for transmitting the rotation of the rotary shaft to an orthogonally disposed axle when transversely mounted on the rib of the wing structure neighbouring the wingtip.

4. A mechanism as claimed in claim 1 further comprising a second slat smaller than the first mentioned slat and superimposed thereon, the second slat being pivoted on the first mentioned slat * so as to move over the first mentioned slat, the shape of the leading edge of the second slat being adapted to that of the first mentioned slat, both slats being adapted to be simultaneously driven by a single slat actuating means so as to create two operationally juxtaposed wing slots, the free ends of both slots being at the wingtip.

5. A method of changing the wingplan geometry of aeroplanes in flight comprising sliding forward a slat which is lengthwise pivotally mounted to a main wing of the aeroplane so as to match the leadingedge of the main wing, so that the slat is angularly projected over the said leading-edge, forming an adjustable angle "a"increasing the wing chord, and/or sliding the slat downward to create a wing slot forming an angle "b"which changes the wing camber, the said sliding operations collectively improving the aeroplane flight stability at low speeds on take-off and when landing.