Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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1 This invention relates to rocke-t missiles and is particularly concerned
with a control system for a command to line of sight, guided missile.
~ control system in accordance wi-th the invention comprises, in a
guided missile~ means for rotating the missile about its axis; a discharge
nozzle so directed that the thrust therefrom has a lateral component relative
to the missile and a reaction motor associated with said nozzle and arranged
to deliver, in response -to a suitable signal, a thrust, appropriately timed in
relation to the roll position of the missile and of appropriate duration~ for
correcting the missile trajectory.
The rotation o~ the missile may be produced by known means such as a
torque rocket or a rifled launcher and may be maintained by means of canted
fins. Preferably the roll speed is approximately constant. The nozzle is
preferably located so that the line of thrust therefrom passes -through or near
the centre of gravity of the missile so that lateral, bodily movement is imparted
to the missile while induced pitching or yawing is reduced to a minimum. This
in turn improves the missile~s response to accelera-tion demands and reduces -the
required beam angle and power of any -tracking beacon wi-th which the missile may
be provided. The thrust may also have a forward component, parallel to the
missile a~is to assist in overcoming aerodynamic drag. The required timing and
duration of the thrust may be computed, in known manner from the observed posi-
tion of the missile relative -to the required trajectory and a sui-table signal
may be transmitted to the missile through a radio or trailing wire link by
means of a sui-table pulse encoder. The techniques for achieving this are known
and the specific arrangement required in this case does not form part of the
present invention and will not be further described.
The invention further provides a reaction motor for use in -the control
system, said mo-tor comprising a combustion chamber; a discharge nozzle to
which -the combustion chamber has access by way of a relief valve; a coml~ressible
fuel tank which can be pressurised by gases from the combustion chamber and
which communicates with the combustion chamber -through an injection system in-
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1 corporating an injector, a differential piston pump, actuable by pressure of
gases from the combustion chamber, for feeding fuel to the injector and a
valve operable on command, to control pressure on one side of the differential
piston; and means for initially heating and pressurising the combustion chamber.
The relief valve may conveniently comprise a simple, spring closedvalve arranged to open, when the gas pressure in the combustion chamber rises
above a predetermined value, to allow gas to discnarge through the nozzle.
The fuel tank may comprise an inner container, made wholly or partly of flex-
ible material such as rubber or a plastics material, which is located within
a rigid outer container and can be pressurised by combustion gases admitted
into the outer container. Alternatively the inner container may be in the
form of a bellows. A third form of tank may consist of a cylinder one end
wall of which constitutes a piston to whose outer face the combustion gases
have access. In this last form of tank the piston forming its end wall may
constitute the differential piston pump though this may, of course, be a
separate structure located elsewhere in the injection system. The command
operable valve may, conveniently, be solenoid actuated and may control the
passage of the combustion gases to the differential piston or may control
an exhaust port communicating with the opposite side of the piston. The
means for initially pressurising and hea-ting the combustion chamber may
comprise an electrically initiated, solid propellant igniter the gases from
whose combustion will serve to provide an initial working pressure in the
chamber and other parts of the motor and will also be hot enough to ignite
fuel entering the chamber via the injector. The initial pressurisation and
heating may alternatively be achieved by igniting an initial charge of fuel
by means for example of a spark plug.
Several forms of the invention will now be more particularly des-
cribed, by way of example only, -~ith reference to the accompanying drawings
in which:-
Figure 1 is a partly diagrammatic, side elevation of a missile
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1 incorporating a control system in accordance with the invention,
Figure 2 is an enlarged axial section of a part of the missile show-
ing the control system,
Figure 3 is a cross section on the line III-III of Figure 2,
Figure 4 is a section similar to Figure 2 showing an alternative
form of control system, and
Figure 5 is a diagrammatic drawing of a modified form of the motor
shown in Figure 4.
The missile shown in Figure 1 has a body 1 of conventional form
having-the usual tail fins 2 which may be canted to sustain the roll
initially imparted in known manner by a torque rocket 3. Situated amidships
in the body 1 is a control motor including a combustinn chamber 4, a fuel
tank 5, a discharge nozzle 6 and an injection system 7 arranged to inject
fuel, on command, into the chamber 4.
The construction and functioning of the control system will be
better understood by reference to Figures 2 and 3 where they are illus-trated
on a larger scale in greater detail. The combustion chamber 4, has, mounted
internally on its cylindrical wall, a generally cylindrical nozzle housing ~
incorporating a valve 9 whose stem 9a is carried in a valve guide 10 supported
by a cross-member 11 flxed in the housing ~. The end of the stem 9a remote
from the valve carries a flange 12, and a spring 13 in compression between
this flange and the cross member 11 urges the valve inwardly onto an out-
wardly facing seating 14 at the inner end of the nozzle 6 which is thereby
closed. The combustion chamber communicates with the interior of the
nozzle housing, inwardly of the valve 9~ through orifices 15 so that gas
pressure in the combustion charnber tends to open the valve 9.
The fuel tank 5 consists of a rigid outer container 16, whose walls
may, though not necessarily, incorporate a part of the missile wall, and
a flexible inner container 17 of a material such as rubber or a plasticO
The combustion chamber communicates with the interior of the outer container
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1 16, exteriorly of -the inner container 17, through a pipe lg which, as shown,
runs longitudinally along the outer surface of the missile.
The injector system 7 comprises a solenoid actuated ball valve 19,
a second stage pressure controlled valve 20 actuable by a differential piston
21, a differential piston pump 22 (best illustra-ted in Figure3) and an injector
23 with the necessary connecting tubes and channels. Details of the solenoid
19a, which actuates valve 18, are not shown since this may have any convenient
constructinn and is actuable in known manner in response to a signal transmitted
from a ground control station through trailing wires, a radio link or other
convenien-t, known means. The combustion chamber 4 communicates -through
channels 24, 25 with one side of the solenoid valve 19 which is actuable through
a push rod 19b by means of the solenoid 19a. The other side of valve 19
communicates, through a channel 26, with the lower, larger area, side of a
pis-ton 21 which controls the second stage valve 20. This valve opens or closes
communication between the combustion chamber 4 and the pump 22 by way of
channels 24, 27, 2g, and pipe 29. The pipe 29 provides access to the inter-
space 30 between a bulkhead 31 and a differential piston 32 in the recipro-
cating pump 22 which incorporates, below the piston 32, a fuel chamber 33.
An annular space 32a between the smaller cross-sectioned par-t of the piston
32 is vented to atmosphere through parts 32_. The combustion chamber 4 also
communicates, by way of channels 24, 24a directly with the upper, smaller area,
side of differential piston 21.
The fuel chamber 33 of the pump 22 receives fuelfrom the tank 5 by way
of a connector 34, a pipe 35 (Figure 2) and a non return valve 36 (Figure 3),
and is also connected through an outlet 37 and a pipe 3g wi-th -the injector
23. The injector 23 comprises a cylindrical casing 39 formed or mounted on
the wall of the combustion chamber to which it has access through an injection
orifice 40; and an injector piston 41 slidable in -the casing 39 and carrying,
on the side thereof adjacent the injection orifice 40, a spigot 42 projec-ting
axially therefrom. The spigot 42 has a conical tip which normally closes the
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1 injection orifice 40, being so biased by an injector spring 43 lncompression
between the injector piston 41 and a cap 44 which constitutes the end wall o:E
the casing 39. A splash plate 47 is provided adjacent the injection orifice
4o.
Before the missile is fired, the tank 5 and the pump chamber 33 and
injector 23 are filled with mono-propellant fuel such as isopropyl nitrate
~hrough a filler valve 45. At launch, the combustion chamber 4 is preheated
and pressurised by firing an igniter 46 of solid propellant or, alternatively,
a priming charge of liquid propellant may be fired by means of a spark plug.
The pressure is immediately transmitted from the combustion chamber to the
fuel tank by way of tube 1~ and also to the upper side (direct) and lower side
(through the solenoid valve 19 which is open at this stage) of-the differential
piston 21 which is thus moved upward, closing the second stage valve 20. The
pressure applied at this stage (the working pressure) is insufficient to over-
come the springs 13, 43 closing the relief valve 9 and injector 23 respect-
ively. Roll is imparted to the missile by firing the torque rocket 3 and is
maintained in flight by the canted fins 2. On receipt of the appropriate
signal, the solenoid valve 19 is closed by operation of the solenoid 19a,
cutting off the gas supply to the lower side of piston 21 and, at the same
time venting the lower side to atmosphere through the solenoid valve, -thus
allowing the piston 21 to move to its lower position (as shown in Figure 2)
under the influence of the gas pressure applied to its upper surface. This
movement allows the second stage valve 20 to open, admitting gas to the inter-
space 30 above the pump piston 32. The gas pressure on the pump piston 32
applies an intensified pressure, through this differential piston, to the fuel
in chamber 33 some of which fuel is forced through the outlet 37 causing fuel
to be injected into the combustion chamber 4 through the injector 23 since
the intensified pressure issuEficient to overcome the injector spring 43.
The injected fuel ignites in the hot combustion chamber and the
increased pressure thus developed opens relief valve 9 whereupon gas is
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1 discharged from the nozzle 6 to provide a trajectory-correcting thrust.
After the required duration, the solenoid valve 19 again opens allowing gas
pressure to close the second stage valve 20 whereupon the interspace 30 of
the pump is vented to atmosphere through valve 20 and orifice L~ allowing
the pump piston 32 to rise again, the chamber 33 being refilled with fuel
from the tank through non return valve 36. The pump 22 must clearly be of
sufficient capacity to cater for the greatest thrust duration which is likely
to be required.
The alternative form of motor shown in Figure 4 is somewha-t simpler
in construction and has a combustion chamber 50 located on one side of a
large, cup shaped, differential piston 51 on the other side of whose base is
a fuel tank 52. The piston 51 slides in a cylinder ha-ving a s-tepped bore the
smaller part of which constitutes the fuel tank 52 and accommodates the smaller,
base end of the wall of the tank. The larger portion of the bore accommodates
an enlarged por-tion 53 of the differential piston and encloses an annular
chamber 5L~ betweenits inner surface and the outer wall of the piston 51 for
most of the length of the latter. A nozzle 55, closed by a relief valve 56
whose stem 56a is carried in a guide 57 within a nozzle housing 5~ and which
iB biased closed by a spring 59, is mounted in one wall of the combustion
chamber 50 which has access to the inner side of the val~e 56 through orifices
60. This nozzle and valve are basically similar in construction and in opera-
tion to those described with reference to Figure 2. In this alternative motor,
an injector 61 basically similar in construction to that shown in Figure 2 is
mounted on the end wall 62 of the piston 51 and com~unicates with the fuel
tank through pipe 63. The injector has a piston 64 carrying a spigot 65
which normally closes an injection orifice 66 under the action of a spring
67.
The annular space 5L~ is vented to a pipe 6~ -through orifice 69 and
the pipe 6~ is vented to atmosphere through a valve 70 normally closed by
solenoid 71.
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4~ 5
1In operation the missile has roll imparted in the manner previously
described which roll is main-tained bycanted fins. The combustion chamber
50 is preheated and pressurised at launch by means of an igniter ~O, prior
to which the fuel tank 52 and injector 61 will have been filled with fuel and
the interspace 54 filled with a suitable pressure fluid. Gas pressure in -the
combustion chamber 50 is, at this stage, insufficient to overcome the spring
closure of the relief valve 56 and movement of the piston 51 is prevented by
the pressure of the fluid in the annular space 54. On recelpt of a suitable
signal, the solenoid valve 70 is opened allowing the fluid from annular space
1054 to bleed to atmosphere. The piston 51 now moves toward the fuel tank 52
and fuel is injacted into the combustion chamber 50 where the increased
pressure resulting from its combustion overcomes the spring 59 of the relief
valve 56 which opens allowing gas to discharge through nozzle 55. At the end
of the required duration the solenoid valve 70 closes, movemen-t of the piston
51 ceases and fuel ceases to be injected into the combustion chamber 50. Sub
sequent operation of the solenoid valve 70 will cause the piston 51 to continue
its movement,the piston stroke merely being interrupted during closure of the
valve.
The further modification, sho1~n diagrammatically in Figure 5, dispenses
20 with the annular space 54 and pressure fluid of the arrangement of Figure 4,
the solenoid valve being incorporated with the injector in a communication
link between the fuel tank and combustion chamber. In this modified arrange-
ment, a quite differently shaped~ differential piston 72 constitutes the
dividing wall between a combustion chamber 73 and a fuel tank 74 which
constitu-te parts of a cylinder 75. The combus-tion chamber 73 is provided,
as before, with a combination nozzle and relief valve 76 and the tank 74
and combustion chamber 73 are in communication by way of a pipe 77, through
a solenoid valve and igniter which may be incorporated in a single unit 7~
mounted in the wall of the combustion chamber 73. Structural details of the
30 various items are not shown in this case, they may be similar to those
already described.
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1 It will be clear that many variations may be made in the above
described systems within the scope o~ the present invention. The injector,
for example may be replaced by a vortex type nozzle, the relief valve may be
of any convenient construction as may also the solenoid valve and other items
of the injection system. Spin may be imported by means of a rifled launcher
instead of by a torque rocket and may be sustained by means of canted nozzles
on the main driving motor.
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