AIR VEHICLE AND DEPLO YABLE WING ARRANGEMENT THEREFOR

FIELD OF THE INVENTION

This invention relates to air vehicles, specially to controllable air vehicles, and particularly having deploy able wings.

BACKGROUND OF THE INVENTION

Controllable air vehicles such as airplanes, projectiles, missiles, and the like are well known. Some examples are included in the following patents.

US 5,615,846 discloses a deployable diamond shaped wing for use in extending range or increasing maneuverability of guided missiles or munitions. A hardback mechanism attaches the wing kit to the top part of an existing guided munition or missile and the forward wing is attached with a forward wing pivot assembly so as to allow the forward wing to rotate in the horizontal plane. The rear wing is comprised in the hardback and is attached to a driveshaft and carriage with a rear wing pivot that allows rear wing rotation in the horizontal plane. The forward wing and rear wing are joined at the wingtips with a wing tip pivot pin and folded laterally along the hardback for storage. A motor is mounted within the hardback and connected to the driveshafts in a manner to cause the carriages to move fore and aft. After launch, the lifting surfaces are extended by powering the driveshaft to move the carriages longitudinally aft with the attached rear wing pivot and to cause the wings to form a diamond shaped lifting surface. The wings can be retracted by reversing the procedure. The entire wing kit assembly is attached to an inventory weapon and launch platform by using the existing suspension points with new hardback lugs.

US 6,845,937 discloses a reusable, mach-velocity mobile platform that includes a generally tubular shaped body having an aft and forward end, and a payload section. An arch wing is supported by the body aft end. The arch wing has an upper and a lower wing joined at distal ends by two curved end plates. A nose assembly is connected at the forward end having an upward directed fixed angle-of-attack to generate forward end lift. In US 5,899,410 an aerodynamic body, such as an aircraft, includes a lengthwise extending fuselage and a pair of coplanar joined wings extending outwardly from opposed sides of the fuselage. The pair of coplanar joined wings are formed by at least

two forward wings extending laterally outward and rearward from opposite sides of a forward portion of the fuselage, and at least two aft wings extending laterally outward and forward from opposite sides of a rearward portion of the fuselage. Each aft wing is joined to a respective forward wing at a common wingtip to thereby form one of the joined wings. In particular, the aft wing can either be joined to the outermost portion of the respective forward wing or to a medial portion of the respective forward whig such that a portion of the forward wing extends outboard of the common wingtip. In either embodiment, the forward and aft wings of the joined wing aircraft define respective planes which are mutually coplanar. US 3,942,747 discloses an aircraft of the Canard type in which a first airfoil is attached to an aft fin portion of the fuselage at a higher elevation than a second airfoil which is attached to the fore portion of the fuselage. The second airfoil extends outwardly and rearwardly to meet the first airfoil whereby a triangular configuration is formed in plan view and in front elevation view. US 4,365,773 discloses an aircraft having a fuselage and a pair of first airfoils in the form of wings extending outwardly from the vertical tail and a pair of second airfoils in the form of wings extending outwardly from the forward portion of the fuselage at a lower elevation than the first airfoils. The second wings extend rearwardly having a positive dihedral so that the tip ends of the second airfoil are located in close proximity to and may overlap the tip ends of the first wings. The pairs of wings along with the fuselage present a double triangle or diamond shape in both front elevational view and top plan view. A winglet structurally connects the tip ends of the corresponding first wings and second wings, and these winglets have airfoil surfaces which extend vertically substantially beyond the tip ends of the first and second wings in order to minimize the effects of induced drag and also to augment directional stability of the aircraft.

US 4,146,199 discloses a fore mounted aft swept and aft mounted forward swept wings extend from either side of a lifting body fuselage. Each lateral pair of the wings is joined at the tops by a wing tip vortex translating device to induce translation of the tip generated vortices along the trailing edge of the aft wings. End plates extend rearwardly from the maximum chord thickness of the fuselage to increase the effective lift of the fuselage.

US 5,141,175 discloses a device having pop-out wings and a guidance and control system is detachably mounted on a munition such as a bomb and is used to extend the range capability of the munition. Prior to launch, the wings are folded together. The control system is contained within a saddle portion of the device, and when the munition is released from the aircraft, the wings are caused to pop out to their flying position. The saddle is secured to the munition through a single bolt. When the target area is reached, the device is jettisoned by detonating a charge which shears the securing bolt, thereby permitting the device to pivot rearwardly and separate from the munition. US 6,745,979 discloses a spacecraft such as a fly back booster or a reusable launch vehicle, or an aerospace plane, having a fuselage and a set of scissors wings consisting of two main wings. Both of the main wings are rotatably mounted on the fuselage and can be yawed at opposite directions.

SUMMARY OF THE INVENTION

According to one aspect of the invention, a deployable wing arrangement

(referred to synonymously as a deployable wing kit) is provided for use with a longitudinally extending fuselage, for example of a projectile, bomb, or other stores, having an upper portion and a lower portion, the kit comprising: a first pair of wings pivotably mountable with respect to said upper portion and capable of being deployed from a first retracted position to a first deployed position; a second pair of wings pivotably mountable with respect to said lower portion and capable of being deployed from a second retracted position to a second deployed position; a strut arrangement comprising at least one pair of struts, wherein one or another strut of said pair of struts respectively interconnect one or another of said first pair of wings with one or another of said second pair of wings. According to one aspect of the invention, the upper surface and lower surface of the fuselage are spaced, and the first pair of wings is spaced from the second pair of wings at least along a direction generally orthogonal to the longitudinal axis of such a fuselage.

The deployable wing arrangement or kit may further comprise an actuation mechanism adapted for selectively deploying said first and second wings from said first and second retracted positions, respectively, to said first and second deployed positions, respectively. The actuation mechanism may be configured for deploying said first and second wings substantially concurrently one with respect to another.

At least one of said first wings and second wings comprises substantially zero taper (i.e., a taper ratio of unity). The first pair of wings comprises a first port wing and a first starboard wing. Optionally, in said first retracted position, said first pair of wings assume a position generally aligned with said fuselage. The deployable wing arrangement or kit according to the invention may further comprise a suitable housing for stowing at least a part of each said first wing when in the first retracted position. The first wings may be pivotably mounted with respect to said upper portion via a first hinge arrangement. In said first deployed position, said first pair of wings assume a backward swept position with respect to said fuselage, for example having a sweep angle between about 20° and about 30°.

The second pair of wings comprises a second port wing and a second starboard wing. Optionally, in the second retracted position, said second pair of wings may assume a position generally aligned with said fuselage. In the second deployed position, said second pair of wings may assume a forward swept position with respect to said fuselage, for example having a sweep angle between about -30° and about -40°. The second wings may be pivotably mounted with respect to said lower portion via a second hinge arrangement.

Each said strut interconnects a corresponding said first wing with a corresponding said second wing in a manner such as to synchronise said deployment of said first wing with said deployment of said second wing. Each said strut pivotably interconnects a corresponding said first wing with a corresponding said second wing via a third hinge arrangement, for example. Optionally, each said strut may comprise an aerodynamic profile, in particular a symmetric aerofoil, configured to increase lateral maneuverability to said air vehicle at least when said first wings and said second wings are in their respective said first and second deployed positions. Each said strut may comprise a pair of spaced end portions joined by means of a central arched portion, wherein each said end portion is pivotably mounted to one or another corresponding said first and second wings via said third hinge arrangement.

The deployable wing arrangement or kit may comprise a strongback adapted for enabling said wing arrangement to be mounted onto an upper portion of a longitudinally extending fuselage, said strongback comprising said first hinge arrangement. The second hinge mechanism may be axially movable with respect to said first hinge mechanism from a first axial position to a second axial position, an axial position of said first hinge mechanism being substantially fixed with respect to said strongback, such that at said first axial position said second wings and said first wings are at said second and first retracted positions, respectively, and wherein at said second axial position, said second wings and said first wings are at said second and first deployed positions, respectively. Further, said actuating mechanism may be configured for selectively moving said second hinge mechanism from said first axial position to said second axial position such as to cause said second wings to be deployed from said second retracted position to said second deployed position, and so as to cause, via said third hinge arrangement, said first wings to be deployed from said first retracted position to said first deployed position. By way of non-limiting example, the actuator arrangement may comprise any one of or combination of: a mechanical actuator, a pneumatic actuator, a hydraulic actuator, aerodynamic actuator; and electrically- actuable actuator.

Each said strut may be pivotably connected to a corresponding said first wing at a wing tip thereof, or alternatively at a position inboard of a wing tip thereof, or alternatively at a position substantially intermediate a wing tip and a wing root thereof.

Each said strut may be pivotably connected to a corresponding said second wing at a wing tip thereof, or at a position inboard of a wing tip thereof, or at a position substantially intermediate a wing tip and a wing root thereof. According to another aspect of the invention, an air vehicle is provided, comprising: a longitudinally extending fuselage having an upper portion and a lower portion; and a deployable wing arrangement or kit according to the first aspect of the invention.

The air vehicle may comprise a plurality of stabilizing fins mounted to said fuselage. The fins may be deployable from a retracted position substantially

accommodated within said fuselage to a deployed position substantially outside of said fuselage.

The fuselage may comprise at least one of: a guidance system, an electro optics system, a laser system, a radar system, a reconnaissance system, optionally housed in a nose section of the fuselage or elsewhere in the fuselage. The fuselage may comprise at least one of: a payload, a warhead, a reconnaissance system; optionally housed in a center section of the fuselage or elsewhere in the fuselage. The fuselage may comprise a propulsion system, optionally housed in an aft section of the fuselage or elsewhere in the fuselage. The air vehicle may comprise a deployment mechanism for enabling the air vehicle to be selectively deployed from an attachment station of a carrier air vehicle. The deployment mechanism may comprise at least one suspension lug configured for cooperating with a support hook comprised on said carrier air vehicle.

The present invention also relates to a method for increasing the range of an air vehicle comprising a fuselage, comprising providing a deployable wing arrangement or kit according to the invention, and mounting the same on said vehicle, imparting a forward velocity at a predetermined altitude to the vehicle, and deploying the wings of said wing arrangement. In one embodiment the air vehicle is air launched from a carrier vehicle to impart said forward velocity at a predetermined altitude to the air vehicle. In other embodiments, the air vehicle may be ground launched along a suitable trajectory, for example with the aid of booster rockets.

Some features of at least some embodiments of the invention may include the following:

Large aspect ratio wings provides induced drag reduction, and enables the air vehicle comprising the wing arrangement of the invention to have a larger range than otherwise.

The general diamond configuration for the wing arrangement (in plan view) in the deployed configuration thereof allows the use of high aspect ratio wings, while maintaining static stability margin in pitch of the air vehicle on which the wing arrangement is mounted, hi other words, the hinge point of the upper wings may be moved forward, thus allowing the span of the wing to be increased (such that the wing tip, in retracted position, does not significantly extend aft beyond the end of the vehicle).

The sweep angle provided by the wings when in the deployed configuration reduces transonic drag with respect to a similar wing arrangement having zero sweep angle.

The side struts provided between the upper wings and the lower wings allow easy and synchronized deployment of the upper and lower wings, and moreover can increase the skid-to-turn maneuverability by reducing the lateral stability margin of the vehicle and adding vertical surfaces.

The box-like structure formed between the upper wings and lower wings via the side struts provide better aeroelastic properties, and weight advantages than a comparable single wing structure having similar aerodynamic and structural performance.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to understand the invention and to see how it may be carried out in practice, embodiments will now be described, by way of non-limiting example only, with reference to the accompanying drawings, in which:

Figs. Ia to Id illustrate deployment stages of an embodiment of the invention. Fig. 2 illustrates in top/rear isometric view the embodiment of Figs. la-Id in the fully deployed configuration.

Fig. 3 illustrates in bottom/rear isometric view the embodiment of Figs. Ia- Id in the fully deployed configuration.

Fig. 4 illustrates in top/rear isometric view the strut of embodiment of Figs. la- Id by itself.

Fig. 5 illustrates in rear view the embodiment of Figs. Ia- Id in the fully retracted configuration. Fig. 6 illustrates in front view the embodiment of Figs. Ia- Id in the fully deployed configuration.

Figs. 7a to 7c illustrate alternative embodiments of the invention. Fig. 8 illustrates in top/rear isometric view the deployable wing kit of the embodiment of Figs. Ia- Id in the fully deployed configuration. Fig. 9 illustrates in bottom/rear isometric view the deployable wing kit of the embodiment of Figs. Ia- Id in the fully deployed configuration.

DETAILED DESCRIPTION OF EMBODIMENTS

According to one aspect of the present invention, a deployable wing arrangement is provided in kit form for fitting, or retrofitting, to a suitable body such as the fuselage or body of an air vehicle. According to another aspect of the invention, an air vehicle is provided, comprising a deployable wing arrangement of the invention, either integrally or removably fitted with respect to a fuselage or body of the vehicle.

According to an embodiment of the invention, an air vehicle comprising a deployable wing arrangement is illustrated in Figs. 1 to 6, and is generally designated with the numeral 10. The air vehicle 10, which may be configured for use as a projectile, for example, such as a guided weapon, for example, comprises an elongate fuselage 20 and a deployable wing arrangement 30. Optionally, the deployable wing arrangement 30 may be provided in kit form and fitted to the air vehicle body such as the fuselage 20.

Referring in particular to Figs. 2 and 3, the fuselage 20 comprises a forward or nose section 11 serially connected to, or integrally formed with, a center section 12 and an aft section 13. The nose section 11 comprises a streamlined fairing and may house, for example, a guidance system and/or a radar system and/or a reconnaissance system and/or an optical system and/or a laser system, and so on. The center section 12 and/or the aft section 13 may accommodate, for example, a payload and/or a warhead and/or a reconnaissance system. Optionally, and in other variations of this embodiment, the center section 12 and/or the aft section 13 may comprise a propulsion system, such as for example a rocket motor, ramjet engine, turbojet engine, and so on, together with a suitable fuel system. Further optionally, other propulsion units may be mounted to the fuselage, for example on the sides thereof at the said aft section 13. However, in this embodiment, the air vehicle lacks a propulsion system, and the air vehicle 10 is an air launched gliding weapon or the like, propelled by virtue of the momentum imparted thereto by other means, such as a mother or carrier air vehicle e.g., a military aircraft or other weapons platform for example.

The aft section 13 further comprises a plurality of stabilizing and/or control fins 14, which are deployable from a stowed, folded or retracted position (Fig. Ia), in which the fins 14 are housed in forward facing recesses 35 (Fig. 3) accommodated in the fuselage 20, to a deployed position (Fig. Ib), in which the fins 14 are radially projecting from the aft section 13 to an outside of the fuselage 20. Deployment of the fins 14 may

be achieved using any means known in the art, for example by a spring loaded mechanism, pyrotechnic means, and so on. The fins 14 are optionally pivotable in a controlled manner about suitable journals (not shown) aligned with radial axes generally orthogonal with respect to a longitudinal axis 99 of the fuselage 20, to provide directional control to the air vehicle 10. In the illustrated embodiment, the aft section 13 comprises four fins 14, wherein adjacent fins are angularly spaced one from another with respect to longitudinal axis 99 in a substantially uniform manner. It will be appreciated that in other embodiments, more than four fins 14, or less than four fins 14, may be comprised on the air vehicle, typically depending on the specific requirements, mission and so on of the particular air vehicle, for example.

The fuselage 20 is typically of circular cross-section, though may comprise any other suitable cross-section, including, for example oval, polygonal, and so on, and the cross-sectional area thereof gradually increases from the nose section 11 to the center section 12, and may again diminish at or near the aft section 13; alternatively the aft section may be blunt-ended. The fuselage 10 comprises an upper portion 140, and a lower portion 150 diametrically opposed to the upper portion 140 with respect to the centerline or axis 99.

The wing arrangement 30 comprises a saddle or strongback 142, which can be further configured as a wing housing, and provides structural support for the rest of the wing arrangement 30, as well as for the fuselage 20. The strongback 142 is comprised on the upper portion 140 in the illustrated embodiment, and may be joined thereto, for example when the wing arrangement 30 is provided in kit form, or alternatively may be integrally formed therewith. The wing arrangement 30 is mounted onto the fuselage 20 at a position such that when fully deployed, assures sufficient static margin to the vehicle 10.

Referring particularly to Figs. 2 and 5, the vehicle optionally comprises a pair of axially spaced suspension lugs 110 which pass through strongback lug pockets 114 in the strongback 142 and are fixedly connected to suitable lug wells 112, which may constitute standard munitions lug wells when the vehicle 10 is a projectile, for example. The lugs 110 are configured for cooperating with support hooks comprised on a carrier air vehicle, for example, and thus allows the vehicle to be carried by the carrier air vehicle and released when desired. Optionally, the suspension lugs 110 may be configured for locking the strongback 142 with respect to the fuselage 20 by means of

wells 112, and may thus be longer than Standard lugs normally used for the fuselage 20. For example, the lugs 110 may comprise a flange that abuts the upper portion of the strongback 142 in the vicinity of the pockets 114. Alternatively, the lugs 110 comprise an external screwthreaded surface that engages a complementary internally threaded surface in the pockets 114 and wells 112. Other connecting arrangements are also possible.

A number of swaybraces 117, typically a fore pair of swaybraces and an aft pair of swaybraces, may be provided on the aircraft (or indeed the carrier air vehicle when this is not an aircraft) which abut against swaybrace pads 116 on the housing 142 for providing stability to the vehicle 10 while attached to the carrier air vehicle (not shown). The deployable wing arrangement 30 comprises a forwardly mounted first pair of wings, collectively designated 100, an aft mounted second pair of wings, collectively designated 102, and at least one pair of struts, collectively designated 104.

The first pair of wings 100 comprises a port wing IOOA and a starboard wing 100B ₅ each pivotably mounted with respect to the upper portion 140 by means of a suitable hinge arrangement 210 for the forward wings. In this embodiment the hinge arrangement 210 is configured for allowing free pivoting of the wings 100 with respect to the fuselage 20. (In other embodiments of the invention, though, the hinge arrangement may be actuable directly to deploy the first wings 100 - for example the hinge arrangement may comprise a rack and pinion mechanism, wherein the rack is actuated by any suitable powered mechanism, thereby rotating the pinions which in turn rotate the wings 100 to the deployed position. Alternatively, a spring based actuator may use a spring to deploy the wings, for example.) The wings 100 are configured for, and are capable of, being deployed from a first retracted position (Fig. Ia) to a first fully deployed position (Fig. Id), by pivoting about the hinge arrangement 210. hi this embodiment, the position of hinge arrangement 210 is fixed axially with respect to the fuselage 20. The wings 100 in this embodiment are shown as having substantially zero taper, but may alternatively comprise any suitable taper ratio, as required for particular applications of the vehicle 10. In the deployed configuration, the wings 100 are swept back, at a sweep angle which may be, for example, between about 20° and about 30°. In other embodiments, the sweep angle may be zero or negative (swept forward). In the retracted configuration, the wings 100, or at least the trailing edges thereof, are retracted into axially extending slits 232 comprises on either side of a suitable housing 230

comprised on said upper portion 140, which may be integral or separate from the strongback 142. Thus, in the retracted configuration illustrated in Fig. Ia, the wings 100 assume a position generally aligned with said fuselage 20.

The second pair of wings 102 comprises a port wing 102A and a starboard wing 102B, each pivotably mounted with respect to the lower portion 150 by means of a suitable second hinge arrangement 220 for the aft wings. In this embodiment the hinge arrangement 220 is configured for allowing free pivoting of the wings 102 with respect to the fuselage 20. The wings 102 are configured for, and are capable of, being deployed from a second retracted position (Fig. Ia) to a second fully deployed position (Fig. Id), as will become clearer herein. The position of hinge arrangement 220 may be moved from a first, aft axial position Pl to a second, fore axial position P2 with respect to the fuselage 20, and thus the second hinge arrangement comprises a suitable translation mechanism, for example a rail 221 mounted to the underside 150, and a runner (not shown) on which the hinge arrangement 220 is mounted, the runner being configured for axial movement with respect to the rail. The rail 221 may comprise a suitable base 222 for mounting onto the fuselage, and may be faired for minimizing drag thereof. The base 222 may be held in position on the fuselage by means of a belt 290 that is connected to the strongback 142. The aft position Pl is associated with the retracted position of wings 102, and the fore position P2 is associated with the deployed position of the wings 102. The wings 102 in this embodiment are also shown as having substantially zero taper, but may alternatively comprise any suitable taper, as required for particular applications of the vehicle 10. In the deployed configuration, the wings 102 are swept forward, at a sweep angle which may be, for example, between about -30° and about -40°. In other embodiments, the sweep angle may be zero or positive (swept back). In the retracted configuration, the wings 102 assume a position generally aligned with said fuselage 20.

The wings 100, 102 are configured for providing desired lift/drag characteristics in the particular flight regime that the vehicle is designed or desired to operate, and for example may be optimized for transonic flight performance. In particular, the wings 100, 102 may comprise a relatively high aspect ratio, minimizing induced drag.

In the illustrated embodiment, the lower wings 102 comprise a shorter span than the upper wings 100, but in other embodiments the spans may be about the same, or alternatively the lower wings 102 may be longer than the upper wings 100. Further, in

16

-12-

the illustrated embodiment, the tip of each wing 102A ₅ 102B is interconnected with a central portion 108 of the corresponding upper wing 10OA, IOOB respectively by means of port strut 104A and a starboard strut 104B, collectively referred to as struts 104, via an upper hinge 252 and a lower hinge 254. As may be seen in Fig. 4 in particular, each strut 104 comprises a sideways-facing generally U-shaped form, the upper and lower arms 250 thereof being adapted for pivotably mounting the strut 104 to the underside of the corresponding upper wing 100, and to the upper side of the corresponding lower wing 102, respectively, by means of hinge arrangements 252, 254, respectively. The hinge arrangements 252, 254 may comprise, for example, simple pins or journals, comprised in the arms 250 or the corresponding wings, that are receivable in suitable bearings in the wings or arms 250, respectively. The upper arm 250 that is pivotably mounted to the corresponding upper wing 100 comprises a stop 126 which limits the relative rotation between the wing 100 and the strut 104, by abutting and locking against the trailing edge of the wing 100. The base 260 of the strut 104 comprises an arch portion 262 having a concave side 264 that faces the fuselage 20. As may be best seen in Figs Ia and 5, the fuselage 20 comprises a substantially circular cross-section at least at a fuselage part 20A thereof axially aligned with the struts when the upper wings 100 and lower wings 102 are at their respective retracted positions. The concave side 264 of the arch portion 262 comprises a concave curvature generally complementary to the convex curvature of the fuselage part 2OA, which enables the struts 104 to be snuggly retained or abutted against the fuselage part 2OA in the retracted configuration illustrated in Fig. Ia. In other embodiments, the fuselage may be non-circular in cross- section, and the corresponding side struts may optionally be formed to conform to the outer shape of the fuselage in an appropriate manner. The struts 104 act as side force panels, and may comprise a suitable aerodynamic cross-section, typically in the form of a symmetric aerofoil, and are configured to present a substantially zero incidence angle with respect to the fuselage centerline 99 when the wings are fully deployed. This configuration provides the vehicle 10 with the capability of performing skid-to-turn maneuvers, for example when wishing to home onto a target.

Thus, the upper wings 100 are constrained to pivot about a fixed axial position, the struts 104 are constrained to pivot with respect to the wings 100 and with respect to the tip end of the lower wings 102, while the root ends of the lower wings 102 are

constrained to rotate with respect to the hinge arrangement 220 while translating between positions Pl and P2.

In operation, and referring particularly to Fig. Ia, the vehicle 10 may be released from a carrier aircraft on which it is being carried by disengaging the lugs 110 from the deployment mechanism of the aircraft, the wings 100 and 102 being in the retracted configuration, and the struts 104 being close to the fuselage 20.

Alternatively, it is possible to launch the vehicle 10, in the retracted configuration shown in Fig. Ia, by a suitable cannon, or by means of a carrier rocket or the like. (In such cases, it may be that the lugs 110 are not required, and instead the vehicle is equipped with a suitable shell cartridge or rocket propulsion system, etc.) In any case, the air vehicle 10 is imparted with a particular forward momentum and trajectory through the air.

In the next operating stage shown in Fig. Ib, the safe store separation stage of the air launched vehicle, the fins 14 are immediately deployed after the launch in Fig. Ia to provide longitudinal stability to the air vehicle 10, and prevent collision with the aircraft (or other carrier vehicle).

In Fig. Ic, the wing arrangement 30 begins to deploy, and as the hinge arrangement 220 is moved from the aft position Pl to the forward position P2, the wings 102 are constrained to rotate, deploying in a manner such that the tips thereof with the struts 104 are laterally displaced away from the fuselage, causing the upper wings 100 to also deploy outwards. Deployment of the wing arrangement may occur at a predetermined time after the launch in Fig. Ia, or alternatively according to predetermined conditions, for example. Such predetermined conditions may include, for example, the angle and/or rate of yaw/pitch/roll of the vehicle and/or velocity of the vehicle 10, as determined via suitable sensors and instrumentation carried on board the vehicle 10 or strongback 142, for example.

In Fig. Id, the stop 126 limits the angular deployment of the upper wings 100, and thus also of the lower wings 102, locking the wings in a particular diamond-shape configuration in plan view. The hinge arrangement 220 may be configured to be locked in position Pl until it is desired to deploy the wing arrangement 30, using any suitable locking arrangement

(not shown), while allowing the hinge arrangement 220 to freely translate between the positions Pl and P2 when unlocked, without providing an actuation mechanism.

Optionally, an aerodynamic actuator, for example in the form of an aerodynamic mechanism may be provided for inducing an aerodynamic force applied at a strategic point and in a direction such as to deploy the wings 100, 102. For example, the struts 104 may be configured to initially present a positive angle of attack to the incoming airflow such that an aerodynamically induced force having a component in a transverse direction away from the fuselage is created, thereby pulling the struts 104 away from the fuselage, when the hinge arrangement is unlocked, and thus deploying the wings 100 and 102, until the final locked position shown in Fig Id. A suitable mechanism may be provided to counter-rotate the struts about a vertical (translating) axis such that when the strut assumes its final position at full deployment of the wings, the struts present a zero incidence angle with respect to the fuselage centerline 99. Such a suitable mechanism may comprise, for example, a four-bar linkage or the like.

Alternatively, a suitable actuation mechanism may be provided for positively moving the hinge arrangement from position Pl to position P2, thereby deploying the wings 100, 102. The actuation mechanism may be mechanical, for example comprising a spring release mechanism, pyrotechnic-based, pneumatic, hydraulic, electrically operated, or any other form, as is known in the art. In the embodiment illustrated in Fig. 3, a power source (not shown) causes a drive shaft 132 of an actuator (not shown) to translate the hinge arrangement 220. Alternatively, an aerodynamic actuator in the form of an aerodynamically actuated mechanism may be provided. For example, in embodiments where the pivot axis of the lower wings 102 is axially fixed with respect to the fuselage, and the pivot axis of the upper wings 100 axially translates in an aft direction during deployment of the wings, a relatively small drogue parachute tethered to the axially movable upper wing pivot may be deployed such as to induce a rearward aerodynamic (drag) force component on the upper wings at the pivot, enabling the same to deploy. The drogue parachute may be configured to be discarded when the wings 100, 102 are fully deployed.

Alternatively, an actuation mechanism may be provided in strongback 142 and configured for directly deploying the upper wings 100 by rotating the same about their hinge arrangement 210, which in turn causes the deployment of the lower wings 102 via struts 104.

In any case, in the fully deployed configuration illustrated in Figs. Id ₅ 2 and 3, and particularly in Fig. 6, the upper wings 100 are maintained at a vertical spacing from the lower wings 102 by means of the struts 104, which provide a stractural-box-like configuration, which increases the overall effective stiffness of the wings themselves, while potentially providing weight and/or aeroelastic advantages. Further, while the embodiment illustrated in Fig. 6 comprises upper and lower wings with essentially zero dihedral, one or both sets of wings may comprise any desired dihedral angle, so long as the wings may be deployed from a retracted to a fully deployed configuration.

Once the wing arrangement 30 is fully deployed from the compact storage or retracted configuration, the air vehicle 10 is able to glide and maneuver in a more controlled manner than in the absence of the wing arrangement 30, or when the wing arrangement is not deployed, and moreover the deployed wing arrangement 30 increases the endurance or range of the vehicle 10. In particular, there is a considerable induced drag reduction due to the relatively high aspect ratio of the wings, which provide good lift-to-drag performance.

In the embodiments illustrated in Figs. 1 to 6, the wings 100 are longer than wings 102, which deploy to a diamond-shaped configuration, the wings 100 being arranged at a fixed position on the upper part of the fuselage, while the wings 102 are axially movably mounted to a lower part of the fuselage. However, many other variations of the embodiment are possible, for example as follows.

In the embodiment illustrated in Fig. 7a, the lower wings are longer than the upper wing and comprise wing tips that project forward of the struts 104. In the embodiment illustrated in Fig. 7b, the upper and lower wings have approximately the same span, and the struts 104 are located at the tips of the wings, hi the embodiment illustrated in Fig. 7c, the upper and lower wings have approximately the same span, but the struts 104 are located at a position intermediate between the tips and roots of the wings, so that the tips of the bottom wings are forward of the struts 104, while the tips of the upper wings are aft of the struts 104. In the embodiments of Figs. 7a and 7c, the tips of the lower wings need to be sufficiently stiff to withstand the severe bending moments induced by the airflow.

In yet other embodiments of the invention, rather than presenting a diamond shape plan configuration for the wings when deployed, the upper and lower wings may be hinged in order to both deploy in a rear swept, or indeed forward swept, manner,

with the same or different sweep between the upper and lower wings, and a suitable hinge and optionally actuation mechanism allows deployment of the wings in a similar manner to that described for the embodiment of Figs 1 to 6, mutatis mutandis.

In yet other embodiments of the invention, the translation mechanism for the hinge arrangement 220 together with wings 102 may be mounted to the upper part 140 of the vehicle 10, while the wing 100 and housing 142 is mounted to the lower part 150 of the vehicle, the lugs 110 still being in the upper part of the fuselage 20.

In yet other embodiments of the invention, the forward wings 100, whether on the upper or lower part of the fuselage, are pivotably mounted thereto via a translation mechanism, while the rear wings 102 are pivotably mounted, to the lower or upper part of the fuselage, respectively, at a fixed position.

Many other variations of the above embodiments according to the invention are also possible.

According to another aspect of the invention, and referring to Figs. 8, 9, the wing arrangement 30 may be provided in kit form, comprising upper wings 100, lower wings 102, side struts 104, strongback 142 and lower hinge arrangement 222, substantially as described with respect to Figs. 1 to 6, mutatis mutandis. The wing arrangement 30 may be mounted onto any suitable body or fuselage, for example fuselage 20 of Figs. 1 to 6, mutatis mutandis, for example by means of lugs 110, as described above, mutatis mutandis. A brace, clamp, or belt 290 may be used for holding together the second hinge arrangement 220 with the strongback 142, particularly when mounted onto a fuselage as described above, mutatis mutandis.

Many other variations of the above embodiments according to the invention are also possible. In the method claims that follow, alphanumeric characters and Roman numerals used to designate claim steps are provided for convenience only, and do not imply any particular order of performing the steps.

Finally, it should be noted that the word "comprising" as used throughout the appended claims is to be interpreted to mean "including but not limited to". While there has been shown and disclosed example embodiments in accordance with the invention, it will be appreciated that many changes may be made therein without departing from the invention.