EP0447283B1 - Missile control system by means of lateral nozzles - Google Patents

Description

The present invention relates to a system for piloting a missile by means of lateral gas jets and a missile comprising such a system.

It is already known, in particular when a missile must be piloted with high load factors, to provide on board this missile lateral nozzles, capable of being supplied with gas from either a gas generator of the main propellant , or a gas generator specially designed for this purpose. Thus, this results in lateral gas jets generating transverse propulsive forces capable of rapidly and significantly bending the trajectory of the missile. It is possible to ensure that the lines of action of such transverse forces pass through the center of gravity of the missile, or at least in the vicinity of this center of gravity and it is then said that the missile is piloted in force, the response time to the command is therefore particularly rapid. However, this is not an obligation and the lines of action of said transverse forces can pass at points on the axis of the missile different from the center of gravity. Said transverse forces then create, in a manner similar to conventional aerodynamic control surfaces, moments allowing the missile to be controlled in attitude with respect to the center of gravity.

By the US patent US-A-4,531,693 and by the French patent FR-A-2,620,812, a system is already known for piloting a missile by means of lateral gas jets, comprising a gas generator capable of 'be connected to at least one pair of lateral nozzles by means of rotary shutter means, movable under the action of motor means and controlling the passage of gases through said nozzles.

In the system of American patent US-A-4,531,693, each of said nozzles is associated with an individual rotary shutter, itself individually controlled by an oscillator. Thanks to this structure, each rotary shutter can have a low inertia, so that the response time of the shutter means, and therefore of the control, can be very low.

Furthermore, because there is an oscillator for each of said shutters, it is easy to control all of said oscillators so that, at all times, the position of each of said shutters (full opening, total shutter or shutter partial) corresponds exactly to the piloting phase and / or to the state of said gas generator. On the other hand, because of the control of said rotary shutters by oscillators, a controlled position of a shutter relative to the corresponding nozzle is not reached directly, but by a train of oscillations. In addition, these oscillations can induce parasitic oscillations in the missile, complicating the piloting thereof.

On the other hand, in the system of French patent FR-A-2 620 812, each nozzle is associated with a rotary shutter and said shutters are controlled in rotation by a piston sharing a jack in two chambers of different sections, said chambers each receiving a part of the gas generated by said gas generator and the position of said piston being controlled by controlling the flow rate of said gas through the chamber of larger section, the two shutters being linked to each other by a mechanical connection such that , when a shutter rotates with a tendency to close the associated nozzle, the other shutter rotates, of the same angular amplitude, with a tendency to release the associated nozzle.

The object of the present invention is a system of the type mentioned above having, at the same time, shutters with low inertia and a shutter control without oscillations.

• à chaque obturateur individuel est associé un tel vérin, le contrôle desdits débits à travers les chambres de plus grande section des deux vérins d'une paire de tuyères latérales étant tel que, à un instant donné, un seul desdits débits est susceptible d'être restreint, éventuellement jusqu'à l'obturation totale ; et
• ladite liaison mécanique comporte deux bielles respectivement solidaires en rotation d'un obturateur, lesdites bielles étant reliées l'une à l'autre par leurs extrémités libres en regard par l'intermédiaire d'une articulation, dont l'axe est susceptible de se déplacer longitudinalement par rapport à l'une desdites bielles.

To this end, according to the invention, the system for piloting a missile by means of gaseous jets, of the type described last is characterized in that:

• each actuator is associated with such a cylinder, the control of said flows through the chambers of larger section of the two cylinders of a pair of lateral nozzles being such that, at a given instant, only one of said flows is capable of being restricted, possibly until total obturation; and
• said mechanical connection comprises two connecting rods respectively integral in rotation with a shutter, said connecting rods being connected to each other by their free ends opposite by means of a joint, the axis of which is liable to move longitudinally with respect to one of said connecting rods.

Thus, each shutter can have a low inertia, and the positioning of each shutter is determined, without oscillations, both by the corresponding jack, and by the action of said mechanical connection.

Such a joint can be of any known type, for example with a ball joint or a roller rolling in a slot and said mechanical connection is preferably disposed away from the gas flows emitted by the gas generator.

Advantageously, each connecting rod is integral in rotation with the shaft of the corresponding shutter and, at its end opposite to said articulation with the other connecting rod, each connecting rod is articulated to the piston of the corresponding jack.

In the case where the two nozzles are diametrically opposite with respect to the missile body, it is advantageous that, in the neutral position of the system, the two articulations of the connecting rods to said jacks and the articulation between said connecting rods are aligned and that the two obturators obturate half the corresponding nozzles.

In order to minimize the inertia of the shutters, each nozzle has an oblong section, at least in the vicinity of its neck cooperating with a shutter. Thus, each obturator can be constituted by a shaft secured to a projecting radial pallet, the longitudinal end face of which cooperates with the neck of the corresponding nozzle.

Advantageously, in order to reduce the torque exerted by the gases on the shutters and tending to oppose the opening of the latter, the lateral face of the radial vane, facing the neck of the nozzle in the open position of said shutter, is concave and curved.

Preferably, said shutters are mounted in a rigid block integral with the structure of said missile.

When said nozzles are formed in wings of said missile secured to the skin thereof, it is advantageous for the feet of said nozzles to be nested with sliding friction in said rigid block. Thus, the deformations of said nozzles are decoupled from the rest of the missile.

Control of the gas flow through a jack is preferably obtained using a linear motor moving a ball, in a flare provided on the circuit of said gas flow. Preferably, the shutters of the two nozzles are controlled by the same motor.

For control of the system, it is provided that, downstream from its neck cooperating with the corresponding rotary shutter, each nozzle comprises a gas stilling chamber, connected to said nozzle, on the opposite side of said neck, by a throttle such that the gas flow inside said nozzle is subsonic. Thus, it is possible to pilot the missile as a function of the measurement of the pressure inside said stilling chambers.

To this end, a device is provided for measuring the pressure in each stilling chamber.

The figures of the appended drawings will make it clear how the invention can be implemented. In these figures, identical references designate similar elements.

Figure 1 is a schematic view of an exemplary embodiment of the missile according to the invention, with partial cutaway.

FIG. 2 is a partial cross-section, on a larger scale, of the missile according to the invention, along line II-II of FIG. 1.

FIG. 3 is a partial longitudinal section of the missile according to the invention, the left and right parts of this figure corresponding respectively to lines III-III and III'-III 'of FIG. 2.

FIG. 4 schematically illustrates the means of actuation of each shutter member, said shutter members being in the middle position.

FIG. 5 shows an exemplary embodiment of the mechanical coupling connection between said shutter members, in elevation with cutaway and partial section.

Figure 6 is a section along line VI-VI of Figure 5.

Figure 7 is a view similar to Figure 4, one of the shutter members being completely closed and the other completely open.

FIG. 8 schematically shows the application of the system according to the invention to a missile comprising two pairs of nozzles, in longitudinal and orthogonal planes.

FIG. 9 shows an alternative embodiment of the control system of FIG. 8.

The exemplary embodiment of the missile 1 according to the invention, shown diagrammatically in FIGS. 1 to 3, comprises an elongated body 2 of axis LL provided with wings 3 and empennages 4. The wings 3 and the empennages 4 are provided with control surfaces 5 and 6, respectively. The wings 3 are four in number and they are two to two diametrically opposite, the planes of two consecutive wings being orthogonal to each other and passing through the axis LL. Similarly, the empennages 4 are four in number and they are two to two diametrically opposite, the planes of two consecutive empennages being orthogonal to each other and passing through the axis LL. In addition, the tail units 4 are located in the bisector planes of the wings 3.

In the vicinity of the center of gravity G of the missile 1, there is provided, in the body 2, a force piloting device 7 controlling four nozzles 8, two in two diametrically opposite and arranged in the wings 3. The nozzles 8 are placed in the vicinity of the combustion chamber of a gas generator 9, for example with solid propellant, and are connected to said generator 9, by conduits 10.

The nozzles 8 can be connected to the conduits 10 through an inlet orifice 11 and they open to the outside through an outlet orifice 12, of larger section than the inlet orifice 11, said orifices 11 and 12 being connected by a divergent 13. The outlet orifices 12 are located at the longitudinal edge 3a of the wings 3, so that the gas jets passing through the nozzles 8 are separated from the body 2 of the missile and only interfere little with the aerodynamic flow around the skin 2a of said body 2.

As will be explained in more detail below, each of the nozzles 8 is equipped, at its inlet 11, with a shutter or rotary shutter 14 (not shown in FIG. 1) making it possible to close off or at least partially clear the corresponding nozzle 8.

In flight without significant load factor, the action of the force control device 7 is not necessarily necessary, because then the missile 1 can be piloted in a conventional manner thanks to its aerodynamic control surfaces 5 and 6. Consequently, if the gas generator 9 is of the controlled operation type, it may be stopped. If the gas generator 9 is of the continuous operating type, the shutter members 14 of two opposite nozzles are controlled so that the gas jets which they emit exert forces on the missile, the result of which is nothing ; in this case, as will be seen below, the shutter members 14 of the two opposite nozzles are constantly half open to allow the gases produced by the generator 9 to escape.

On the other hand, in flight with a large load factor imposing an abrupt change of orientation of the trajectory of the missile, it is necessary to operate at full at least one of the nozzles 8, to obtain this abrupt change of orientation. Then, the shutter member 14 of the nozzle (s) controlled for operation is completely erased, so that the emitted lateral and transverse gas jet (s) are large and force the missile 1 to change direction abruptly, while the members shutter 14 of the nozzle (s) not controlled in operation completely seal the corresponding nozzles.

It will be noted that, since they are incorporated into the wings 3, the nozzles 8 have the shape of a flattened funnel. The outlet 12 is oblong, the large dimension of its section being parallel to the longitudinal axis L-L of the missile 1, while the small dimension of this section is transverse to said axis L-L. This small transverse dimension is advantageously constant and the ends of the outlet orifice 12 can be rounded.

The inlet or neck 11, located on the inner side of the missile 1, is also oblong, of constant width and with rounded ends. The section of said neck 11 is similar to that of the outlet orifice 12, but smaller than that of the latter. The divergent 13 is connected to the two orifices 11 and 12 by a regulated surface.

The section ratio necessary to sufficiently relax the combustion gases coming from the generator 9 is largely obtained by determining the respective lengths of the orifices 11 and 12.

Thanks to the oblong structure of the nozzles 8, the lateral control jets have the form of plies having a small frontal dimension for aerodynamic flow. As a result, the interactions between said lateral control jets and said aerodynamic flow, already reduced by the spacing of the outlet orifices 12 of the skin 2a of the body 2, are, if not totally eliminated, at least even more reduced, so that the aerodynamic elements 3, 4, 5 and 6 can continue to fulfill their function by cooperating with the aerodynamic flow, even when the lateral control jets are used at their maximum power.

As is particularly visible in FIG. 3, the force control device 7 is composed of two parts 7a and 7b, namely a part 7a in which the shutter members 14 are mounted and a part 7b intended for controlling the said elements obturation organs.

Part 7a of the force control device 7 comprises a central rigid block 15, coaxial with the axis LL and forming a housing inside which the movable closure members 14 are disposed. The rigid block 15 is rigidly connected to the internal structure of the body 2 of the missile 1 by end rings 16, 17. This rigid block 15 is hollow and has an internal recess 18 in communication with the conduits 10 by peripheral openings 19. Furthermore, the rigid block 15 has other peripheral openings, forming the nozzle necks 11 and in communication with the internal recess 18, depending on the obturation members 14.

The rotary shutter members 14 each comprise a shaft 20 of axis ll, parallel to the axis LL of the missile, mounted relative to the rigid block 15 on low friction bearings 21, for example bearings. Each organ shutter 14 comprises a radial pallet 22, integral with the corresponding shaft 20 and projecting outwardly relative to the latter. The outer longitudinal face 22a of the radial vanes 22 cooperates with the corresponding nozzle neck 11 either to close the latter (see the position of the shutter members 14 from the left and from above in FIG. 2), or to release at least partially said nozzle neck 11 (see the position of the shutter members 14 on the right and at the bottom in FIG. 2).

When the shutter members 14 are in this shutter position, they isolate the internal recess 18 of the nozzles 8 and therefore the latter from the conduits 10. On the other hand, when the shutter members 14 are in their release position necks 11, they put the nozzles 8 in communication with the conduits 10, through said nozzle necks 11, the internal recess 18 and the peripheral openings 19.

The axes l-l of the shutter members 14 are respectively arranged in the median longitudinal plane of the nozzles 8.

In order to limit the torque opposing the opening of the nozzle necks 11 by the shutter members 14 (this torque being due to the speeding up of the gases and to the resulting vacuum at said nozzle necks 11 ), the lateral face 22b of the pallets 22, opposite the nozzle necks 11 in the open position of said closure members 14, is concave and curved, profiled to form with the internal wall 18a of the internal recess 18 a convergent in the direction of said nozzle necks 11. Thus, the curved lateral faces 22a serve as bearing faces for the setting in speed of the gases and report the depression generated at a distance from the axes of rotation ll of the shutter members 14.

The projection of the pallets 22 relative to the shafts 20 is reduced so that each closure member 14 has very little rotational inertia and maneuvering movement, so as to obtain a very short response time with a power of minimum order. It is thus seen that, thanks to such an embodiment of the shutter members 14, these have a very low inertia, which allows them to have a very reduced response time, and limit the torque which is opposed at the opening of the nozzle necks, which avoids having to provide complex compensation systems.

Of course, the outer face 22a of the closure members 14 has a minimum clearance relative to the internal wall 18a of the block 15, in order to reduce leaks in the closed position, while allowing the expansions caused by the high temperature of the gases. , for example when these come from a gas generator 9 of the powder type. The choice of the constituent materials of the block 15 and of the shutter members 14, as well as the choice of their shape can also contribute to the minimization of friction: for example, carbon or molybdenum is used, protected or not by coatings or sleeves thermal protection.

Furthermore, as shown in FIGS. 2 and 3, the feet 8a of the nozzles 8 are fitted into indentations 23, of corresponding shape, provided in the external wall of the rigid block 15, so that the connection between said said nozzles 8 and said rigid block 15 is of the sliding adjustment type. Thus, the nozzles 8, which are integral with the skin 2a of the body 2, can follow the deformations thereof. The deformations between the internal rigid structure of the missile 1 and the external skin 2a of the body 2 are thus dissociated, due in part to the significant load factor to which the missile 1 is subjected during the force piloting maneuvers, deformations which would cause operating disturbances.

As can be seen in FIG. 3, the shafts 20 of the shutter members 14 penetrate inside the part 7b (only represented by an outline in phantom) of the force control device 7, intended for the control of said shutter members 14. In Figures 4 to 8, there is shown schematically embodiments of this control part 7b.

In Figure 4, there is shown a pair of opposite nozzles 8, respectively bearing the references 8.1 and 8.2 and associated with respective shutters 14.1 and 14.2. Similarly, the devices respectively associated with said nozzles 8.1 and 8.2 have the same references assigned indices 1 or 2 respectively.

We can see, in this figure 4, that each closure member 14.1 or 14.2 is associated with a cylinder 30.1 or 30.2, the piston 31 of which is connected to said member 14.1 or 14.2 for example by a rod 34, respectively articulated at 35 and 36 on said closure member 14.1 or 14.2 and on the rod 37 of said piston 31.

The piston 31 of each cylinder 30.1 or 30.2 divides the interior of the corresponding cylinder 38 into two chambers 38a and 38b of different sections. In the chamber 38a, of smaller section, opens a conduit 39, for example connected to a conduit 10, introducing the pressure of the generator 9 and tending to push the piston 31 towards the chamber 38b of larger section, possibly up to a position such that the shutter member 14.1 or 14.2 then seals the neck 11 of the corresponding nozzle 8.1 or 8.2. In this case, the piston 31 can come to bear against a stop 40, provided in the chamber of larger section 38b and delimiting the minimum volume that the latter can occupy.

In this minimum volume of the chamber of larger section 38b of a cylinder 30.1 or 30.2 open an intake duct 41 of calibrated section and an exhaust duct 42 of modular section. The intake duct 41 receives, like the duct 39, a portion, for example of the order of 1%, of the gas flow generated by the generator 9 by being for example connected to a duct 10. The exhaust duct 42 is vented, for example by being connected to the outside of the missile 1, so that a slight pressure po prevails in the chamber of larger section 38b. To be able to precisely and quickly modulate the section of the exhaust ducts 42, the free end of the latter is extended by a part 43 flared in a funnel and a refractory ball 44 is provided so as to be able to move inside said flared part 43, in the axis thereof. A motor 45.1 or 45.2, for example a linear electric motor, is provided for such displacement of said ball 44. It can be seen that with such a device, ball 44 is automatically centered relative to conduit 42 in the closed position.

When an engine 45.1 or 45.2 is controlled to retract the ball 44 and completely release the corresponding exhaust duct 42 (see FIG. 4), that is to say to clear between said ball 44 and the wall opposite the funnel 43 has a passage section at least equal to the section of the exhaust duct 42, the gaseous stream entering through the intake duct 41 freely escapes through said exhaust duct 42, so that this stream gaseous exerts only a slight pressure po on the piston 31, which is pushed towards the stop 40 by the action of the gas flow supplied by the corresponding conduit 39, so that the associated link 34 tends to move the corresponding sealing member 14.1 or 14.2 towards the position for which it completely closes the nozzle neck 11.

On the other hand, if an engine 45.1 or 45.2 is controlled to bring the ball 44 closer to the exhaust duct 42, said ball defines with the wall opposite the funnel 43 a passage section which decreases. As soon as this passage section becomes smaller than the section of the exhaust duct 42, there is an obstacle to the flow of the gaseous current entering through the intake duct 41, so that the gas pressure increases inside the chamber of largest section 38b, beyond the value in. As soon as this pressure is large enough to overcome the action of the gaseous current supplied by the conduit 39, the piston 31 tends to move in the direction for which the rod 34 rotates the corresponding closure member 14.1 or 14.2 in the direction of release of the nozzle neck 11.

If the approximation of the ball 44 of the exhaust duct 42 continues, under the action of the engine 45.1 or 45.2), the cross section of the gaseous stream entering through the intake duct 41 further decreases and the pressure inside of the chamber 38b of larger section becomes larger and the corresponding closure member 14.1 or 14.2 tends to assume a position for which it completely releases the neck 11 from the associated nozzle 8.1 or 8.2.

If now the motor 45.1 or 45.2 is controlled to retract the ball 44, a gas passage section is again available between said ball 44 and the wall opposite the funnel 43, so that the pressure decreases in the chamber 38 _b of larger section and that the pressure generated by the gas flow brought by the conduit 39 can push the piston 31 so that the shutter member 14.1 or 14.2 rotates in the direction of shutting the neck 11 .

It follows from what has just been described that, by controlling the motors 45.1 and 45.2, it is possible to control the relative rotation of the shutter members 14.1 and 14.2 relative to the necks 11 of the respective nozzles 8.1 and 8.2 and therefore drive in force said missile, the position of a closure member 14.1 or 14.2 relative to the corresponding nozzle neck 11 depending on the balance of fluid pressures in chambers 38a and 38b.

However, the positions of the shutter members 14.1 or 14.2 do not depend solely on the pressures prevailing in the chambers 38a and 38b of the jacks 30.1 and 30.2, because said shutter members are mechanically coupled to each other in rotation by a mechanical link 50, which is shown diagrammatically in FIG. 4, but an exemplary embodiment of which is illustrated by FIGS. 5 and 6.

As can be seen, in this embodiment, said mechanical connection 50 comprises a connecting rod 51, integral in rotation with the shaft 20 of the shutter member 14.1, and a connecting rod 52, integral in rotation with the shaft 20 of the shutter member 14.2, said connecting rods 51 and 52 being directed towards one another and articulated to one another. For this purpose, for example, the connecting rod 52 comprises a yoke 53 in which is engaged one end 54 of the connecting rod 51. This end 54 is pierced with an oblong opening 55, in which a roller 56 can be rolled, rotatably mounted around an axis 57, integral with the connecting rod 52 and passing through the yoke 53, said axis 57 being parallel to the axes ll of the shafts 20.

At their free ends 58 and 59, respectively opposite to the oblong opening 55 and to the yoke 53, the connecting rods 51 and 52 are articulated respectively on the connecting rods 34 associated with the jacks 30.1 and 30.2 by articulations 35, represented in the form of 'ball joint.

It can be seen that the oblong opening 55 and the roller 56 form, between the connecting rods 51 and 52, an articulation whose axis 57 is capable of moving longitudinally relative to the connecting rod 51, when said connecting rods rotate with the associated shafts 20 .

When, as shown in FIG. 4, the two motors 45.1 and 45.2 are in their neutral position for which their respective balls 44 are spaced from the funnel 43 with which they cooperate and at equal distance from them, the sections exhaust of the two conduits 42 are identical, so that in the chambers 38b of large section of the cylinders 30.1 and 30.2 prevails the same pressure, equal to the value po defined above. Furthermore, the chambers 38a of small section of the jacks 30.1 and 30.2 receive the same pressure of gas coming from the generator 9, so that, in these chambers also, the same pressure prevails, equal to that of the gas stream derived from the conduits 10. As a result, the pistons 31 of the two cylinders 30.1 and 30.2 occupy identical relative positions and each of the nozzles 8.1 and 8.2 is half open. In this neutral position shown in Figure 4, it is advantageous that the mechanical connection 50 is itself in a neutral position for which the two joints 35 and the axis 57 are aligned, as shown in Figures 5 and 6 .

If, from the neutral position shown in FIG. 4, one of the two motors 45.1 or 45.2 is controlled (in FIG. 7, the control of the motor 45.2 is illustrated) the corresponding ball 44 is brought closer to the associated funnel, so that the pressure increases in the corresponding chamber 38b and that the piston 31 is pushed back towards the chamber 38a. As a result, the shutter member 14.2 rotates in the direction for which it increasingly releases the associated nozzle 8.2. However, because of the mechanical connection 50 which takes a broken position, the shutter member 14.1 is itself forced to turn, but in the opposite direction. Thus, as and when the shutter member 14.2 opens the nozzle 8.2, the shutter member 14.1 closes the nozzle 8.1. Such a command can continue until one of the shutters 14.2 is completely open, while the other is completely closed. The latter situation is shown in Figure 7, where the shutter member 14.2 is open and the shutter member 14.1 is in the closed position.

In FIG. 8, the application of the system of FIGS. 4 and 7 is shown diagrammatically, for piloting a missile 1 provided with four nozzles, two with two diametrically opposite and distributed at 90 ° around the axis LL of said missile . In this figure, there are the two opposite nozzles 8.1 and 8.2 described above, to which two identical nozzles 8.3 and 8.4 have been added, crossed with said nozzles 8.1 and 8.2. The nozzles 8.3 and 8.4 are associated respectively with closure members 14.3 and 14.4 and jacks 30.3 and 30.4. The shutter members 14.1 and 14.2 are coupled by the mechanical link 50.12, while the shutter members 14.3 and 14.4 are linked by the mechanical link 50.34. Of course the mechanical connections 50.12 and 50.34 are similar to the connection 50, described above. They intersect in the vicinity of their articulation, and that is why they have a central recess 60 (see FIG. 6).

Furthermore, each pair of shutter members 14.1-14.2 and 14.3-14.4 is associated with a position measuring member of one of said shutter members, bearing the references 61.12 and 61.34 respectively. These position measuring members can be of the potentiometer type and they are intended to communicate, when controlling the shutter members (not shown), the exact position reached by said shutter members. It will be noted that, because of the mechanical connections 50.12 and 50.34. each position measuring member 61.12 and 61.34 delivers signals representative, at the same time, of the positions of the two associated shutter members.

In addition, instead of providing a motor 45 per nozzle as shown in FIGS. 4 and 7, in this embodiment a single motor 45 is associated for two diametrically opposite nozzles: this is how the motor 45.12 controls the shutter members 14.1 and 14.2, respectively associated with the nozzles 8.1 and 8.2, while the motor 45.34 controls the shutter members 14.3 and 14.4, respectively associated with the nozzles 8.3 and 8.4. Each of these motors 45.12 and 45.34 is for example a linear motor of the type described in patent FR-A-2 622 066, comprising an elongated core 62 movable in translation parallel to itself. A ball 44 is carried by each end of the core 62, in order to be able to cooperate with the funnels 43 associated with the exhaust conduits 42 of the jacks 30.1 and 30.2, or 30.3 and 30.4, corresponding, so that when a ball 44 approaches its associated funnel, the other ball 44 moves away from its own and vice versa.

It can therefore be seen that, by controlling the motors 45.12 and 45.34, it is possible to obtain any transverse thrust desired for the force piloting of the missile 1.

It will be noted that, for the neutral position represented in FIG. 4, the position of the balls 44 can be such that the force provided by a piston 31 is equal to the torque which tends to close each shutter member 14. Thus, the connections mechanical 50, which guarantee operating safety, are little used. Furthermore, these mechanical connections 50, arranged in part 7b of the system, are outside the gas flows (passing through part 7a), so that they are subjected to moderate temperatures. The rollers 56 can have the shape of a barrel, so that the mechanical connections 50 tolerate reverse bending.

The servo-control in transverse thrust of piloting can be done, in known manner, by a feedback loop (not shown) ensuring the measurement of the position of each pair of shutter members, using members 61.12 and 61.34 . Operation can be stabilized by regulating the speed of the motors 45, fitted for this purpose with tachometric generators (not shown), over the difference between the positions requested and achieved.

If, as illustrated in FIG. 9, a gas stilling chamber 63 is provided between the nozzle necks 11 and said nozzles 8, these stilling chambers 63 themselves being connected to the nozzles 8 by a constriction 64 of section known, one can ensure that the gas flow in said nozzles is subsonic. By measuring, using devices 65, the pressure in each chamber 63, it is easy to determine the thrust of each nozzle 8 and the resulting value per pair of nozzles.

Claims (14)

1. System for guiding a missile (1) by means of gas jets, comprising a gas generator (9) capable of being connected to at least one pair of lateral nozzles (8) by means of rotary stoppers (14), which can move under the action of drive means (30) and controlling the passage of the gases through the said nozzles, each nozzle (8) being associated with a rotary stopper (14) and the said stoppers (14) being rotationally actuated by a piston (31) dividing a cylinder actuator (30) into two chambers (38a, 38b) of different cross-sections, the said chambers each receiving part of the gas generated by the said gas generator (9) and the position of the said piston being commanded by controlling the flowrate of the said gas through the chamber (38b) of greater cross-section, the two stoppers (14) being linked to each other by a mechanical link (50) such that, when a stopper revolves tending to block off the associated nozzle, the other stopper revolves, by the same angular amplitude, having the tendency to free the associated nozzle, characterised in that:

   - with each individual stopper (14) there is associated such a cylinder actuator (30), the control of the said flowrates through the chambers of greater cross-section of the two cylinder actuators of a pair of lateral nozzles being such that, at a given instant, only one of the said flows is capable of being restricted, possibly to the extent of being totally blocked off; and

   - the said mechanical link (50) comprises two connecting rods (51, 52) respectively rotationally integral with a stopper (14), the said connecting rods being linked to one another by their facing free ends by means of a joint (55, 56, 57) whose pin is capable of moving longitudinally with respect to one of the said connecting rods.
2. System according to Claim 1, characterised in that the said mechanical link (50) is arranged away from the gas flows emitted by the said gas generator (9).
3. System according to one of Claims 1 and 2, characterised in that each connected rod is rotationally integral with the shaft (20) of the corresponding stopper (14) and in that, at its end opposite the said joint with the other connecting rod, each connecting rod is articulated to the piston (31) of the corresponding cylinder actuator (30).
4. System according to Claim 3, for a pair of diametrically-opposed nozzles, characterised in that, in the neutral position, the two joints (35) of the connecting rods to the said cylinder actuators and the joint between the said connecting rods are aligned and in that the two stoppers (14) half-block the corresponding nozzles.
5. System according to any one of Claims 1 to 4, characterised in that, at least in the region of its throat (11) interacting with a stopper (14), each nozzle (8) has an oblong cross-section.
6. System according to Claim 5, characterised in that each stopper comprises a shaft (20) integral with a projecting radial vane (22) whose longitudinal end face (22a) interacts with the throat (11) of the corresponding nozzle (8).
7. System according to Claim 6, characterised in that the lateral face (22b) of the radial vane (22), facing the throat (11) of the nozzle (8) in the open position of the said stopper (14), is concave and curved.
8. System according to any one of Claims 1 to 7, characterised in that the said stoppers are mounted in a rigid block (15) integral with the structure of the said missile (1).
9. System according to Claim 8, in which the said nozzles (8) are made in wings (3) of the said missile integral with the skin (2a) of the latter, characterised in that the bases (8a) of the said nozzles (8) are fitted by sliding friction into the said rigid block (15).
10. System according to one of Claims 1 to 9, characterised in that the flowrate of gas through a cylinder actuator is controlled with the aid of a linear motor (45) moving a ball (44) in a flared part (43) provided in the circuit of the said gas flowrate.
11. System according to Claim 10, characterised in that the stoppers of the two nozzles are actuated by the same motor (45.12 or 45.34).
12. System according to one of Claims 1 to 11, characterised in that, downstream of its throat (11) interacting with the corresponding rotary stopper (14), each nozzle (8) comprises a plenum chamber (63) for the gases, which chamber is connected to the said nozzle, on the side opposite the said throat (11), via a restriction (64) such that the gas flow inside the said nozzle is subsonic.
13. System according to Claim 12, characterised in that a measurement device (65) is provided for measuring pressure in each plenum chamber (63).
14. Missile, characterised in that it comprises a guidance system according to any one of Claims 1 to 13.

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