EP0762531B1 - A wire antenna for a machine - Google Patents

Description

The present invention relates to an antenna wired intended in particular to be embedded in a craft such as aircraft. In particular, the aircraft may be a reconnaissance aircraft or drone in which antenna is used for interference of waves radioelectric.

Such an antenna is generally of the type dipole with a large span of a few meters. The two antenna strands are fixed respectively laterally in front of the fuselage of the aircraft, in front of the wings of the aircraft, and symmetrically by relative to the longitudinal axis of the machine.

When taking off or catapulting the craft, the strands are at a first position at which it are arranged along the fuselage of the spacecraft. In cruising regime of the craft, the strands are suddenly deployed to a second position at which they extend perpendicular to the plane horizontal axial of the aircraft. One of the strands extends laterally to the fuselage up, and the other strand extends laterally down the fuselage.

This antenna considerably increases the drag of the aircraft up to about 50%, and requires aircraft engine power significantly higher than that required for propulsion of the aircraft without antenna. As a corollary, the arrangement of the antenna strands and their trail disrupt the effectiveness of the control surfaces of the craft, particularly that of the rudder also called yaw control.

The present invention aims to remedy the aforementioned drawbacks, and more specifically to provide an antenna whose line increases only by a few percent, that is to say so negligible, the drag of the mobile machine.

To this end, the wire antenna includes a strand and is characterized in that it includes a hull free rotation mounted around the antenna strand. Thanks to this free rotation assembly, the hull is always positioned at zero incidence. The presence of this free hull in rotation brings a gain considerable on the drag of a vehicle carrying the streamlined antenna, compared to the train of this machine with a non-faired antenna. The gain can reach around 50 to 80%.

The hull includes rigid pads cross and spacers between the platelets. The antenna strand slides across the pads and freely the spacers in order to decrease the friction of the hull on the strand. The pads and spacers are extremely light to reduce the inertia of the hull.

The spacers can consist of two symmetrical molded half-spacers having faces glued together in a plane longitudinal to the strand.

Preferably, the hull is translatable with clearance along the antenna strand between a stop attached to one free end of the antenna strand and another stop to which is fixed the antenna strand which forms the root of the hull relative to the fuselage of a mobile machine.

The aerodynamics of the hull is chosen in such a way so that it has an airplane wing profile transversely to the strand. Profile preferably a cord substantially between a quarter and a fifth of the thickness of the profile. The axis of the strand antenna can be located between a leading edge of the hull and an aerodynamic focus of the hull.

As already said, the invention is particularly directed towards an antenna on board a machine mobile such as aircraft. In this case, the strand has a end fixed in the machine and extends in a plane substantially longitudinal to the machine. In particular, the antenna can comprise two symmetrical strands by relative to a longitudinal axis of the machine and developed perpendicular to the plane of lift formed by the wings of the craft. In in other words, each strand extends substantially in a longitudinal rudder plane of the craft.

In order to reduce the effect of the antenna on control surfaces of the craft, particularly when the root of the strands is located at the front of the aircraft, each strand forms an arrow, preferably between 15 ° and 45 ° approximately, with a plane perpendicular to the longitudinal axis of the machine. The aerodynamic focus of the hull is preferably located near the center of gravity of the craft.

The means set out below relating to a strand are identical to means relating to the other strand and arranged symmetrically with respect to the axis longitudinal of the machine.

So as not to increase the thrust when takeoff or catapulting of the craft, a related means the machine deploys the antenna strand only after takeoff from a first position at which the antenna strand is folded substantially against the machine, towards a second position at which the strand antenna forms an acute angle with an axis longitudinal of the machine.

According to a particular embodiment, the strand has a free and bendable portion between a attachment point of the strand linked to the machine and a strand holder to which the antenna strand is attached and forming root of the hull. The free portion of the strand is flexed to said first position and substantially linear at said second position. In a way to avoid any breakage of the strand, the strand holder turns around a center located in an obtuse sector in front the strand and delimited by the strand in the second position and the longitudinal axis of the machine.

The means for deploying may include a guide in the shape of an obtuse circular segment, preferably of the order of 120 °, fixed to the body of the machine. The mobile strand holder then substantially forms a sector circular covering substantially half of the guide and is slidably mounted in the guide for turn from a forward position corresponding to the first position of the antenna strand at a position rear corresponding to the second position of the strand antenna.

Motor means can be provided to activate the means to deploy in order to move the strand antenna from the first position to the second position after takeoff of the craft. This driving force can also be provided to move the strand antenna from second position to first position before landing of the machine.

According to a first embodiment, the antenna includes a strand holder to which the antenna strand is fixed and sliding in a circular slide, and a pull strap having one end attached to a strand holder and another end linked to a means reel, preferably through a return means located substantially along the slide, by example at the rear end of the slide.

According to a second embodiment, the antenna includes a strand holder to which the antenna strand is fixed and sliding in a circular slide, and a threaded rod having one end cooperating with a toothing along a circular edge of said strand holder and another end driven in rotation by motor means.

According to a third embodiment, the antenna includes a strand holder to which the antenna strand is fixed and sliding in a circular slide, and a threaded rod having a first end cooperating with a nut linked to said strand holder and a other end driven by a motor means of preferably through a bevel gear located substantially along the slide.

• les figures 1 et 2 sont des vues schématiques de face et de côté vertical d'un aéronef supportant deux brins d'antenne selon l'invention en position repliée ;
• les figures 3 et 4 sont des vues schématiques de face et de côté vertical d'un aéronef supportant deux brins d'antenne selon l'invention en position déployée ;
• la figure 5 est une vue schématique de dessus de l'aéronef ;
• la figure 6 est une vue de dessus d'une carène d'un brin de l'antenne ;
• la figure 7 est une vue de côté d'une plaquette de renfort de la carène ;
• la figure 8 est une vue en coupe de la carène le long de l'axe longitudinal du brin ;
• la figure 9 est une vue schématique transversale explosée d'un moule pour entretoise de la carène ;
• la figure 10 est une vue en perspective d'un guide du porte-brin d'un brin de l'antenne en position repliée ;
• la figure 11 est une vue en perspective du guide du porte-brin de la figure 10 en position déployée ;
• la figure 12 est un diagramme en coupe transversale schématique à travers la fente du guide montrant le passage d'une position rectiligne à une position fléchie d'une portion de brin d'antenne située entre le porte-brin et un connecteur de câble dans la structure de l'aéronef ;
• la figure 13 est une vue schématique longitudinale verticale, partiellement en coupe en partie supérieure, des moyens de déploiement en position d'antenne repliée selon une première réalisation ;
• la figure 14 est une vue schématique longitudinale verticale, partiellement en coupe en partie supérieure, des moyens de déploiement en position d'antenne repliée selon une seconde réalisation ; et
• la figure 14 est une vue schématique longitudinale verticale, partiellement en coupe en partie supérieure, des moyens de déploiement en position d'antenne repliée selon une troisième réalisation.

Other characteristics and advantages of the present invention will appear more clearly on reading the following description of several preferred embodiments of the invention with reference to the corresponding appended drawings in which:

• Figures 1 and 2 are schematic front and vertical side views of an aircraft supporting two antenna strands according to the invention in the folded position;
• Figures 3 and 4 are schematic front and vertical side views of an aircraft supporting two antenna strands according to the invention in the deployed position;
• Figure 5 is a schematic top view of the aircraft;
• Figure 6 is a top view of a hull of a strand of the antenna;
• Figure 7 is a side view of a hull reinforcement plate;
• Figure 8 is a sectional view of the hull along the longitudinal axis of the strand;
• Figure 9 is an exploded cross sectional view of a mold for the hull spacer;
• Figure 10 is a perspective view of a guide of the strand holder of a strand of the antenna in the folded position;
• Figure 11 is a perspective view of the guide of the strand holder of Figure 10 in the deployed position;
• FIG. 12 is a diagrammatic cross-sectional diagram through the slot of the guide showing the passage from a straight position to a bent position of a portion of antenna strand located between the strand holder and a cable connector in the aircraft structure;
• FIG. 13 is a vertical longitudinal schematic view, partially in section at the top, of the deployment means in the folded antenna position according to a first embodiment;
• FIG. 14 is a vertical longitudinal schematic view, partially in section in the upper part, of the deployment means in the folded antenna position according to a second embodiment; and
• FIG. 14 is a vertical longitudinal schematic view, partially in section at the top, of the deployment means in the folded antenna position according to a third embodiment.

The achievements described below are relating to a wired dipole type antenna on a mobile device, such as an aircraft A of the type drone to board a shuttle plane and to catapult from this one.

As shown schematically in Figures 1 to 5, the antenna is made up of two fine metal strands cylindrical 1S and 1I protruding from the nose NE of aircraft A in front of wings AI thereof. The strands are always arranged in an axial plane longitudinal of the aircraft, preferably vertical, that is to say in a plane perpendicular to the wings AI aircraft according to the illustrated embodiments, and symmetrically with respect to the longitudinal axis XX of the aircraft.

At rest, and during the catapult of the aircraft, the strands 1S and 1I are at a first position, called folded position PR, and are arranged along the aircraft fuselage FU, as shown in Figures 1 and 2. Free ends 10S and 10I of the strands are arranged towards the rear of the machine. Extremities 11S and 11I of the strands mounted so as to pivot flexible "in the structure of the aircraft are arranged towards the front of the aircraft. One of the 1S strands are arranged above the aircraft and the other strand 1I is located below the aircraft.

After catapulting, the strands are deployed at a second position, called the deployed position PD, by 4S and 4I deployment means which will be described later. In this deployed position, the strands 1S and 1I are perpendicular to the longitudinal axis XX of the aircraft, or according to the embodiments described below, form an arrow FL of the order of 15 ° to 45 ° with a transverse plane of the aircraft, as shown in Figures 3 and 4.

Referring to Figures 6 to 8, the portion of each of the strands of the antenna external to the aircraft includes a very light aerodynamic hull in airplane wing shape to reduce drag antenna strands. Knowing that the strands are identical, we will refer in the following to the strand higher 1S for example.

As shown particularly in Figure 7, the transverse profile of the hull 2S of the strand 1S includes a substantially ogival leading edge 20, a body 21 narrowing in the form of a bevel from the leading edge 20 toward a trailing edge 22 to the back of the hull.

According to the embodiment illustrated in Figures 6 to 8, the hull structure is composed of several plastic plates 23 distributed almost regularly along the strand 1S antenna and having the transverse profile described above and shown in Figure 7. Platelets form wing reinforcement ribs and have circular holes 231 traversed by sliding by the antenna strand 1S. Between these plates, foam sections, for example foam reinforced rigid or semi-rigid polyurethane, form light spacers 24 also having the profile transverse external shown in figure 7.

As shown in Figure 9, each spacer in foam 24 is obtained by means of a mold for molding one of two identical half-spacers which are glued against each other in a plane longitudinal mediator 21P of the hull 2S. The mold includes a punch and a die. Hallmark 241 has a flat internal surface 242 which corresponds in the median plane of the hull 21P. A protuberance semi-cylindrical 243 projects on the surface 242 and is complementary to half of the cylindrical duct longitudinal 244 in a spacer crossed by the strand 1S. The matrix 245 has an internal face 246 which reproduces the transverse external half-profile of the hull.

In order to minimize the friction of the hull 2S on the strand 1S and therefore all risk of blocking in rotation of the hull which would make the aircraft ungovernable, the 1S strand would cross freely the cylindrical conduits 244 formed at the front of the foam spacers 24, wider than the plate holes 231. In addition, the friction metal on plastic of strand 35 in the platelets 23 can be further decreased by wrapping the strand in a plastic sheath such as Teflon. Under these conditions, the hull 24 may freely rotate around the carrier strand 1S 2S hull, almost without friction, and so position themselves freely at zero incidence in order to stay in the wind bed as well when deployment of antenna strands only during the regime of aircraft cruise with antenna strands deployed.

As shown in detail in Figure 8, the hull 2S is also mounted in free translation on a short distance, that is to say with a large clearance, the along the carrying strand 1S. At the free end 10S of the strand 1S is screwed on a plug 12 which forms a first stop limiting the sliding of the hull 25 outwards. On the side of the other 11S end of the 1S strand entering the fuselage FU of the aircraft, the translation of the 2S hull is limited by a second stop formed by a movable profiled strand holder 3S constituting a hull root independent of the displacement of the hull in rotation and translation. As we will see below, the 3S strand holder is mounted at perpendicular rotation to strand 1S in the structure of the aircraft.

In order to fix the ideas, an antenna according to the invention to scramble waves electromagnetic in the metric and decimetric is composed of strands 1S and 1I having each a length between a quarter wave and about half a wave. To get a trail of the streamlined antenna on the order of 5% of the drag the aircraft without antenna and therefore a low lift faired strands, thickness E of hulls 2S and 2I is between a quarter and a fifth of the chord C of the hulls, i.e. the width of the hulls. For example, the length L of the hull 2S, 2I of each strand is about 1.5 m, the cord C of the hull is 74 mm, the thickness E of the hull is 18 mm, the diameter of the strand 1S, 1I and the holes 231 in the plates 23 is 17 mm, and the axis of the insert holes 231 and spacer holes 244 is located 14 mm from the front of the leading edge 20.

Thanks to wind tunnel measurements, it was shown that the influence of the antenna on the control surfaces of the aircraft is related to the distance between the focus FA aerodynamics of the hull and center of gravity G of the aircraft. So that the antenna does not destabilize the aircraft, and in particular does not intervene predominantly on the effects of control surfaces of the aircraft, in particular of the control surface direction GD of the aircraft, the aerodynamic focus FA hull 2 is provided in front, from the center of aircraft gravity G, as shown in Figure 5. Preferably, the aerodynamic focus FA is located at the vicinity of the aircraft center of gravity G. It is indeed imperative to have hull root 3S, 3I as far back as possible on the FU fuselage so that the shrouded strands do not disturb not the effects of the control surfaces as well during the deployment of the antenna in cruise mode the aircraft.

When the roots 3S and 3I of the strands 1S and 1I fairings are relatively in front of the center aircraft gravity due to location other elements including lift on the rear of the FU fuselage, the strands deployed have an arrow FL which can be chosen between 15 ° and 45 °, preferably around 30 ° depending on the illustrated realization, to move back the AF foci of hulls.

To obtain the stability of each of the hulls 2S and 2I when the aircraft is in cruise, the axis of rotation formed by the strand antenna 1S, 1I is located in front of the focal point FA of the hull, i.e. between the focal point FA and the edge hull 20, as shown in the figure 7. Typically, the distance, called "static margin", between the axis of the strand 1S, 1I and the aerodynamic focus FA of the hull is around 5% of the cord C of the hull 2S, 2I.

Deployment means to deploy simultaneously the shrouded strands 1S and 1I are identical and symmetrical about the axis longitudinal XX of the aircraft. As a result, one of them relative to the upper strand 1S is described in detail with reference to Figures 10 to 12.

The means of deployment 4S of the upper strand 1S includes a guide 40 for the respective strand holder 3S. The guide 40 has a circular segment shape and extends perpendicular to the FU fuselage, in a vertical axial plane of the aircraft A. It is fixed to the structure of the aircraft by two 4C consoles. Guide 40 has a transverse slot 41 in segment circular which is approximately 120 ° depending on the illustrated realization. The rope of the slit segment opens out appreciably at the surface of the fuselage and can be protected at the front by a cover aerodynamics attached to the FU fuselage. Singing circular 42 of the guide through which the slot opens 41 inside the aircraft is surrounded by two circular rails 43 with L-profile concentric with segment and attached to the structure of the aircraft.

The 3S strand holder forming the root of the hull has a circular edge on which is fixed a rigid U-shaped profile 31 which is slidably mounted between edge 42 of guide 40 and rails 43, which form a circular slide 42-43 for guide the 3S strand holder with slot 41. Like this appears by comparing Figures 10 and 11 and as shown schematically in Figure 12, the strand holder 3S has the sensitive shape of a circular sector relative to an angle PB substantially equal to half of that FE relating to the circular segment defining the slot 41 in the guide 40. Under these conditions, at the folded position PR shown in FIG. 10, the strand holder 3S occupies substantially the half segment relative to the guide slot 41 and located towards the front of the aircraft, and in the deployed position PD shown at Figure 11, the 3S strand holder occupies substantially the other half segment relating to the guide slot 41 and located towards the rear of the aircraft.

As shown schematically in Figure 12, after crossing the hull 2S, the strand 1S is fixed, for example by gluing, in a short duct internal practiced in the top 32 of the strand holder substantially in extension of the leading edge 20 of the 2S hull. Then a portion 13 of the strand 1S crosses freely a front slot 33 of the 3S strand holder, particularly in the folded position PR (Figure 10), and the slot 41 of the guide 40 up to a connector 14 attached to the structure of the aircraft. The connector connects the 1S strand to a 15S coaxial power cable coming out of a 16S power amplifier from a interference source installed in the NE nose of the aircraft. The 16S amplifier is separated by a central cooling plate 17 from another 16I amplifier powered by a 15I coaxial cable the other antenna strand 1I.

In the deployed PD position, the attachment point of the strand 1S materialized by connector 14 is substantially on the axis of the strand and the strand is substantially straight. In the folded position PR, the portion 13 of strand 1S is bent with a curvature whose radius is large enough to avoid any bending or breaking of the strand, particularly on exit from the duct to the top 32 of the strand holder.

To meet this condition, the fictitious rotation CR corresponding to the slide circular composed by the edge of strand holder 42 and by the rails 43 and the circular edge 31 of the strand holder sliding in the slide is located in a obtuse front angular sector formed between the body of fuselage FU of the aircraft, and therefore the longitudinal axis XX, and the strand 1S in the deployed position PD. As this appears in Figure 12, the portion of the strand 1S fixed in the top 32 of the 3S strand holder does not pass by the CR center of rotation in order to avoid any strand crack.

In the three realizations of the driving part means for deploying the antenna strands described below, the arrangement of the elements component the means of deployment is symmetrical relative to the longitudinal axis XX of the aircraft, as are the antenna strands 1S and 1I and the strand guides 3S and 3I, and a motor means central to deploy the antenna strands is common to the two deployment means 4S and 4I. In these three realizations, when the strands 1S, 1I must be deployed, the activation of the motor means is simultaneous with unlocking devices ES and EI snap fastening ends free 10S and 10I of the hulls against the fuselage FU of the aircraft, as shown in Figure 2.

According to the first embodiment shown in Figure 13, each deployment means 4Sa, 4Ia includes a traction strap 5Sa, 5Ia. The end front of the strap is attached to the rear end of the circular edge 31 of the respective mobile strand holder 3S by means of a captive nut 51Sa, 51Ia. The rear end of the strap is connected to a motor means consisting of a strap winder compression spring 6a. The strap is applied against the small co-circular wings of the rails slide 43 from the captive nut 51Sa, 51Ia up to a deflection pulley 52Sa, 52Ia mounted mad at the rear end of the respective guide 40.

In the folded position PR, the spring of compression is compressed, i.e. the retractor is armed before takeoff or catapult of the aircraft, and the traction straps 5Sa and 5Ia are unwound.

A mechanical timer means or electromechanical or such a timer means remote control, after takeoff or catapulting of the aircraft, release of the spring compressed in the reel 6a so as to wind the 5Sa and 5Ia straps which then pull the strand holders 3S and 31 backwards. The strands slide in the respective guides 40 in the opposite direction until reaching the deployed position PD.

Referring to Figure 14, a means of 4Sb, 4Ib deployment according to the second embodiment includes a wheel and worm system. The opinion endless is a threaded rod 5Sb, 5Ib rigid in nylon extending longitudinally in the aircraft. At level of a screw bearing 51Sb, 51Ib under the middle of the respective slide 42-43, one front end of the rod meshes with a corresponding toothing provided on the circular edge 31 of the strand holder respective 3S, 3I. A rear end of the rod meshes with a bevel gear 52Sb, 52Ib linked to a respective end of the shaft of a electric motor 6b.

Under the control of an armed timer before take off or catapult, or remote-controlled, the electric motor is activated to turn the threaded rods 5Sb in opposite directions and 5Ib so that the strands 3S and 3I turn towards the rear by sliding in the respective guides 40. At least one limit switch 7Db deployment is arranged at the rear end of one of the guide rails 42-43 to be actuated by a stop on the rear end of the strand holder respective 3S in order to cut the power to the motor 6b.

A 4Ss, 4Ic deployment means depending on the third embodiment shown in Figure 15 includes also a wheel and worm system. However, the worm is a threaded rod flexible 5Sc, 5Ic which is developed substantially parallel to the rear circular half-edge of the respective slide 42-43. The front end of the 5Sc, 5Ic rod meshes with a 51Sc, 51Ic nut fixed to the rear end of the circular edge 31 of the strand holder respective 3S, 3I. A bevel gear 52Sc, 52Ic connects the rear end of the slide respective to a respective end of a motor electric 6c.

When the motor 6c is activated, the rotation of the 5Sc rod, 5Ic is screwed into the 51Sc nut, 51Ic, which passes between the respective rails 43 in direction of the respective bevel gear 52Sc, 52Ic. A limit switch 7Dc deployment is also planned at the end rear of one of the guide rails 42-43.

Preferably in the second and third achievements, the electric motor 6b, 6c can reverse direction of rod rotation threaded so that the strand holders pass from the antenna position extended PD to position antenna folded PR, before landing the aircraft, and the free ends 10S and 10I of the hulls fit into the devices ES and EI locking mechanism. In this case, at least one fold-out limit switch 7Rb, 7Rc is provided at the front end of one of the slides guide 41-42 to be actuated by stopper the front end of the respective strand holder for cutting the power supply to the motor 6b, 6c.

According to other embodiments, and depending on the type of aircraft and particularly its wings, strands with their means of deployment are positioned in a horizontal plane, i.e. are parallel to the wings and elevators of the aircraft.

Claims (19)

1. A wire antenna comprising a wire (1S), characterised in that it comprises a hull (2S) mounted for free rotation around the antenna wire (1S) .
2. An antenna according to claim 1, characterised in that the hull comprises rigid transverse plates (23) and struts (24) between the plates, the antenna wire (1S) traversing the plates (23) slidingly and the struts (24) freely.
3. An antenna according to claim 2, characterised in that the struts (24) consist of two symmetrical moulded half-struts having surfaces (21F) stuck one against the other in a longitudinal plane with respect to the wire.
4. An antenna according to any one of claims 1 to 3, characterised in that the hull is movable in translation with clearance along the antenna wire between a stop (12) fixed at one free end of the antenna wire (1S) and another stop (3S) to which the antenna wire is fixed, preferably forming a root for the hull.
5. An antenna according to any one of claims 1 to 4, characterised in that the hull (2S) has an aircraft wing profile transversely of the wire (1S), the profile preferably having a chord (C) substantially contained between one-quarter and one-fifth of the thickness (E) of the profile.
6. An antenna according to claim 5, characterised in that the axis of the antenna wire is situated between a leading edge (20) of the hull and an aerodynamic focus (FA) of the hull.
7. An antenna according to any one of claims 1 to 6, characterised in that the said wire (1S) has one end (14) fixed in a craft (A) and extends in a substantially longitudinal plane with respect to the craft.
8. An antenna according to claim 7, characterised in that the wire (3S) extends substantially in a longitudinal plane of the rudder (GD) of the craft (A).
9. An antenna according to claim 7 or 8, characterised in that the wire forms a boom (FL), preferably contained between approximately 15° and 45°, with a plane perpendicular to the longitudinal axis (XX) of the craft (A) .
10. An antenna according to any one of claims 7 to 9, characterised in that an aerodynamic focus (FA) of the hull (1S) is situated near the centre of gravity (G) of the craft (A) .
11. An antenna according to any one of claims 7 to 10, comprising a means (4S) connected to the craft (A) to deploy the antenna wire (1S) from a first position (PR) in which the antenna wire is retracted substantially against the craft, into a second position (PD) in which the antenna wire forms an acute angle with a longitudinal axis (XX) of the craft.
12. An antenna according to claim 11, characterised in that the wire (1S) comprises a free portion (13) which can bend between a fixing point (14) of the wire connected to the craft (A) and a wire holder (3S) to which the antenna wire (1S) is fixed and forming a root for the hull (2S), the said free portion of the said wire being bent in the said first position (PR) and substantially linear in the said second position (PD) .
13. An antenna according to claim 12, characterised in that the wire holder (3S) turns about a centre (CR) situated in an obtuse sector in front of the wire (1S) and defined by the wire in the second position (PD) and the longitudinal axis (XX) of the craft.
14. An antenna according to claim 12 or 13, characterised in that the deploying means comprises a guide (40) in the form of an obtuse circular segment, preferably in the order of 120°, fixed to the craft body, the said movable wire holder substantially forming a circular sector substantially covering half of the guide (40) and being mounted slidably in the guide to turn from a front position corresponding to the said first position (PR) of the antenna wire into a rear position corresponding to the said second position (PD) of the antenna wire.
15. An antenna according to any one of claims 11 to 14, comprising a drive means (6a, 6b, 6b) for activating the deploying means (4Sa, 4Sb, 4Sc) in order to displace the antenna wire from said first position (PR) into said second position (PD) after take-off of the craft, and preferably from the said second position (PD) into the said first position (PR) before landing of the craft.
16. An antenna according to any one of claims 7 to 15, comprising a wire holder (3S) to which the antenna wire (1S) is fixed and sliding in a circular guide (42-43), and a traction strap (5Sa) having one end (51Sa) fixed to a wire holder (3S) and another end connected to a take-up means (6a), preferably via a gearing means (52Sa) situated substantially along the said guide (42-43).
17. An antenna according to any one of claims 7 to 15, comprising a wire holder (3S) to which the antenna wire (1S) is fixed and sliding in a circular guide (42-43), and a screwthreaded rod (5Sb) having one end co-operating with a toothing along a circular edge (31) of said wire holder (3S) and another end (52Sb) driven in rotation by a drive means (6b).
18. An antenna according to any one of claims 7 to 15, comprising a wire holder (3S) to which the antenna wire (1S) is fixed and sliding in a circular guide (42-43), and a screwthreaded rod (5Sc) having a first end co-operating with a nut (51Sc) connected to said wire holder (3S) and another end driven by a drive means (6c) preferably through a bevel gearing (52Sc) situated substantially along the guide (42-43) .
19. An antenna according to any one of claims 1 to 18, comprising another wire (1I) about which another hull (2I) is mounted for free rotation, the wires (1S, 1I) being disposed symmetrically with respect to a longitudinal axis (XX) of a craft (A) supporting the antenna.

Images