The present invention deals with a method for setting up an arc-type wing.

In particular, the invention deals with a method for real-time measuring distances connected to a system for correcting the attitude of an arc- type wing.

An arc-type wing falls within the systems for extracting energy from wind through ultra-light wings, with high aerodynamic efficiency, subjected to high wing loads, under tension-structure mode.

An arc-type wing is subjected only to pure tensional forces, generating an aerodynamic lift useful, at the same time, both for keeping its own shape and for generating energy.

The terms used in this document have the following meaning.

Angle of Attack: is the angle between the wing chord of any aerodynamic profile and the apparent wind. For an arc-type wing, the global angle of attack is generally deemed as the angle between apparent wind and mean line of aerodynamic chord profiles in the central bay section.

Center of Pressure: is the point in which all aerodynamic forces generated by an aerodynamic profile can be deemed operating. For kites of an arc-type wing, the center of pressure if at the 10- 20% of the chord.

Chord line: is a line traced through the wing section from the front edge to the outlet edge.

Lift to Drag ratio: is the ratio between the lift forces and the resistance forces supported at a given wind speed.

Load line: for an arc-type wing, it is the line from end to end passing through the center of pressure of all sections composing the wing.

Luffing: it is the trend of the angle of attack of an arc-type wing to suddenly become negative .

Resistance to stalling: it is advisable that arc-type wings have a low stalling speed and that they can recover from a possible stall with minimum increase of apparent wind.

The shape of these wings is approximately semicircular in the plane perpendicular to the apparent wind direction. The limits of the capability of an arc-type wing to respond to changes of apparent wind conditions have a great incidence on its functional usefulness, above all of its use in the energy field.

Such limits are: stalling, luffing and wing shoulder collapsing.

The problem of automatically real-time controlling a wing supported by wind is dealt with by US6260795, in which the use of piezoelectric sensors, actuators and software is disclosed, these being designed to imitate in real time, the reactions of aerodynamic bird-type flights under extreme wind conditions.

In view of this prior art, object of the present invention is proposing an arc-type wing capable of correcting its own attitude during a flight through a retro-actuated system.

In compliance with the present invention, said object is obtained by an arc-type wing with high aerodynamic efficiency, composed of a central arc section connected to pairs of bridles through a pair of shoulders, characterized in that a detecting system measures the difference of meaningful heights, to determine the wing shape in real time.

The above and other objects and advantages of the invention, as will result from the following description, are obtained by a method for setting up di an arc-type wing as claimed in Claim 1. Preferred embodiments and non-trivial variations of the present invention are the subject matter of the dependent claims.

It is intended that all enclosed claims are an integral part of the present description.

It will be immediately obvious that numerous variations and modifications (for example related to shape, sizes, arrangements and parts with equivalent functionality) could be made to what is described, without departing from the scope of the invention, as appears from the enclosed claims.

The present invention will be better described by some preferred embodiments thereof, provided as a non-limiting example, with reference to the enclosed drawings, in which:

figure 1 shows an axonometric view of an arc- type wing equipped with panels with air brakes;

figure 2 shows an axonometric view of an arc- type wing equipped with fuselage-type tail planes; figures 3a, 3b show a geometric configuration diagram of an arc-type wing in two time phases; figures 4a, 4b, 4c show a diagram for real-tme measuring distances connected to a system for correcting the attitude of an arc-type wing of the invention;

figure 5 shows a diagram of a system or measuring the distance and for transmitting ultrasound signals through a RF module installed in panels on board the wing;

figure 6 shows an ultrasound sensor of the space type used in the measuring system of figure 6.

An arc-type wing 1 comprises control bridles 11, 12, connected in different points to drive the wing during its flight and check its angle of attack.

The arc-type wing 1 is composed of a central arc section 13 connected to the bridles 11, 12, through due arc sections 14 possibly extended with a tapered tangent section (not shown) .

Each section composed of the arc 14 and possibly of its respective tapered tangent section makes a shoulder of the arc-type wing 1.

Each shoulder supports a panel 2 which comprises an air brake 21 composed of a flow deflector or spoiler. Each air brake 21 generates a resisting force allowing to introduce a yaw moment useful to restore the maneuver reactivity of the arc-type wing 1.

A optical system 4 comprises a micro-camera 41 and a target 42, respectively assembled on the pair of panels 2 (figures 4a, 4b, 4c) .

The optical system 4 allows measuring in real time the difference of heights, dl-dl', d2-d2' , of meaningful parameters for the shape variation of the wing 1 (figure 3) .

This application has been devised to find relative displacements of the due shoulders and, through the use of the air brakes 21, to suitably correct the attitude of the arc-type wing 1 taking it bac under maximum efficiency conditions.

The micro-camera 41 assembled on one of the two panels 2 is aimed to the target 42 placed on the second panel 2. Through processing of data by a processor applied in the panel 2, the relative displacements dl-dl', d2-d2' are found, necessary to formulate the feedback command acting on the air brakes 21 in order to take back the wing 1 to its ideal configuration.

The optical system 4 allows maneuvering an arc-type wing 1 equipped with servo-assisted tail planes 3, by intervening on the angle of attack both of the central wing section 13, and of the two shoulders (figure 2) . Through the optical system 4, a geometric measure is performed of the distance and of the parallelism of the shoulders, after which a pitch angle is imposed for every servo- assisted tail plane 3, obtaining the correct angle of attack of the central wing section 13, thereby performing the same function of the length change of the rear bridles. In the same way, a geometric measure is performed of the distance and of the parallelism of the shoulders, after which a roll angle is imposed for each servo-assisted tail plane 3, obtaining the correct angle of attack di each shoulder, allowing to modify the wing shape, thereby performing the same function of the asymmetrical or shape change of the arc-type wing 1.

An alternative to the optical system 4 is given by a distance measuring module 5 based on the use of an ultrasound sensor 51 and y the transmission of ultrasound signals through a RF module installed in the panel 2 and ale to transmit and receive radio-frequency signals (figures 5, 6) . Both sensor 51 and RF module are installed in the respective panel 2.