US2448007A

US2448007A - Self-controlled projectile

Info

Publication number: US2448007A
Application number: US471781A
Authority: US
Inventors: Waldemar A Ayres
Original assignee: Sperry Corp
Current assignee: Sperry Corp
Priority date: 1943-01-08
Filing date: 1943-01-08
Publication date: 1948-08-31
Anticipated expiration: 1965-08-31
Also published as: GB605188A

Description

w. A. AYRES 2,44%;007

SELF-CONTROLLED PROJ EGTILE Filed Jan. 8, 1943 Sheats-Shoet 1 ATTORNEY W. 5A. AYREs 2,448,007

SELF-CONTRGLLED PROJEGTILE Film1 Jam. 8, 1943 2 Sheets-Sheet 2 ToRouE MoToR -52 FIG. 3.

Elevdon Cmfrol RANGE es INVENTOR WALDEMARA. AYRES ATTORNEY Patented Aug. 31,1948

2,448,007 SELF-CONTROLLED PROJECTILE Waldemar A. Ayres, Kew Gardens Hills, N. Y., as-

slgnor to The tion of Delaware Sperry Corporation, a corpora- Application January 8, 1943, Serial No. 471,781 9 Claims. (Cl. 244-14) The present invention relates generally to means for and methods of striking a stationary or moving object with a target-seeking high explosive charge, and the invention has reference more particularly to a novel explosive-bearing and self-steering body adapted, upon being initially directed substantially along the line of sight to a target, to continuously maintain its direction of motion along said line of sight, even as the same changes, and so to strike the target.

All commonly known explosive-bearing bodies designed to strike and explode against a target such as bombs, gun projectiles, torpedoes, etc.. have fixed time-space relationships, or trajectories, from the moment they leave their associated control apparatus. The control apparatus associated with such explosive-bearing bodies ordinarily includes radio or optical means for dening a line of sight to the target and obtaining target range, and also some kind of predicting and computing mechanism. This predicting and computing mechanism attempts to predict the' future position of the target from the behavior of the present position, and then computes the initial direction of motion which must ,be imparted to the explosive-bearing body in order that its xed and known trajectory will intersect the target at the predicted future position.

Obviously, in determining what the initial course of the controlled body should be, the predicting and computing mechanism can only take into account the conditions existing up to the time the body leaves the control apparatus. Therefore, any unpredictable variations from the initial known conditions, such as changes inthe itargets course or speed, which occur duringithe flight' of the body, necessarily result in the explosive-bearing body missing the target, since no control is exerted over the body after it leaves the control apparatus.

The probability of a material variation in the initial conditions occurring during the time of flight obviously can be reduced by decreasing the time of flight, that is, by approaching closer to the target before the body is allowed to follow its own predetermined trajectory. However. such a procedure is sometimes impractical and always dangerous. For example, the closer a, torpedo plane is flown in toward the target before its torpedo is released, the greater is the probability of a hit, but the greater also is the possibility y that the torpedo plane, itself, will be hit by antiaircrat nre from the target either before or after the torpedo is released.

' In the present invention it is proposed to mount on an explosive-bearing body its own control apparatus whereby its direction of motion may be continuously controlled throughout its time of.

flight. In this way the body may be released at a point so far removed from the target as to be out of range of its defensive weapons. Moreover, since the direction of motion of the body may be continuously compensated for changing conditions right up until the time that the body strikes the target. it would seem that 'an extremely high percentage of hits could be expected.

In the present application the inventor has exemplied his invention as a targeteeeking aerial or glider torpedo adapted to be released from a carrier aircraft. The carrier aircraft need only be equipped with means for dening a line of sight to the target so that an initial direction of motion substantially along the line of sigh/t may be imparted to the aerial torpedo. The aerial torpedo itself is equipped with radio means for defining a line of sight. and means for sensing and deriving signal voltages proportional to the deviation of itsvown direction of motion with respect to the line of sight, both in elevation and azimuth. In addition, there is lncluded in the equipment mounted on the aerial torpedo a servo control system, responsive to said deviation, or error, signal voltages. and actuating the control surfaces of the torpedo in the proper sense to reorient the torpedo along the lline of sight to the target, thus reducing the signal voltages to zero. .In this way the aerial torpedo is continuously aimed or directed toward the target and made target-seeking. and must eventually strike and explode against the target. In one embodiment of the invention, information obtained from the radio sighting apparatus mounted on the aerial torpedo is transmitted to the carrier craft thus eliminating duplication of sighting means.

Accordingly, the principal object of the present invention is to provide a self-steering targetseeking and explosive-bearing body adapted to steer itself into and explode against a predetermined target.

Another object of the invention is to provide, on an explosive-bearing body, automatic means for controlling its direction of motion so as to strike and explode against a predetermined target.

A further object of the invention is to provide a self-steering and explosive-bearing body adapted, upon being initially directed along the line of sight to a target, to automatically maintain its direction of motion along said line of sight to said target even as the same shifts.

A still further object of the invention is to provide an aerial or glider torpedo adapted upon being released from a carrier craft in the general direction of a target, to continuously and automatically control its own trajectory so as to intercept the target.

A still further object of the invention is to provide means for enabling an aircraft pilot to strike a target with a high-explosive charge adapted to be released from said craft.

Other objects and advantages willbecome apparent from the specification, taken in connection with the accompanying drawings wherein the invention is embodied in concrete form.

In the drawings.

Fig. 1 is a schematic drawing illustrating a preferred embodiment of the present invention.

Fig. 2 is a front elevation view of the aerial torpedo.

Fig. 3 is a schematic representation of the servo system of Fig. 1.

Fig. 4 is a diagram illustrating the instantaneous angular and spatial relationships of the aerial torpedo with respect to the target at three successive stages in the flight of the aerial torpedo.

Fig. 5 is a schematic representation of apparatus mounted on the carrier aircraft in one embodiment of the invention.

Fig. 6 is a drawing of a typical presentation appearing on the face of the cathode ray tube of Fig. 5.

Similar characters of reference are used in all of the above figures to indicate corresponding Darts.

Referring now to Fig. 1, there is shown a target-seeking aerial or glider torpedo I and its associated control equipment, all of which will be understood to be mounted on the aerial torpedo. The aerial torpedo I is equipped with the steering or control surfaces of an ordinary glider,

that is, the elevator 2, rudder 3, and ailerons As shown in Fig. 2, the aerial torpedo I is provided wit'h wings having considerable dihedral in order to insure stability of the torpedo about its normally horizontal fore and aft axis. If desired, the required lateral stability could alternatively-be obtained by the provision of a horizon gyro adapted to produce signal indications corresponding to any rotation of the torpedo about its fore and aft axis. A conventional horizon gyro of the type used in well-known automatic pilot systems could be employed for this purpose. These signals could then be employed through a suitable servo system to provide an aileron control, which control would be superimposed upon the banking angle control of the ailerons which is hereafter described.

The associated control equipment of the aerial torpedo I may be conveniently divided as to function by the dash line 5--5, as shown in Fig. 1, the apparatus above the line 5--5 serving to define a line of sight to the target and to produce on leads 6 and 1 voltage error signals indicative of the angular displacement of the glider axis with respect to the line of sight, and the apparatus below the line 5--5 serving to control the direction of motion of the glider so as to reduce the error signals to zero and thus maintain the glider continuously directed toward the target.

The upper portion of the equipment, that is, the line of sight defining system, is illustrated as a reflected-pulse type of ultra high frequency system of the kind employed for tracking purposes in copending application Serial No. 441,188, entitled Radio gun control system, and filed April 30, 1942, in the names of C. G. Holschuh et al., although any radio system adapted to define a line of sight and produce voltage signals proportional to the elevation and azimuth thereof could as well be used. As described in that application, a control oscillator 8 provides a voltage of suitable synchronizing and control frequency which may be in the audio range. The output of control oscillator 8 is connected, as by lead 9, to a pulse generator I0 which converts the substantially sinusoidal oscillations fed to it into pulses of any desired shape, magnitude, and duration. having a repetition rate equal to the frequency of oscillator 8. This device employs well-known clipping, differentiating, and other suitable waveshaping circuits in the conventional manner and consequently seems to require no further explanation.

The pulse generator I0 supplies trigger pulses to a pulse transmitter I2, as on lead II, causing an ultra high frequency oscillator, included within the pulse transmitter I2, to be biased on momentarily. Transmitter I2 is thus caused to produce extremely short pulses, of perhaps one micro-second duration, of carrier frequency, which pulses are fed through wave guide I3 to a scanning radiator Iii.

The scanning radiator I4 may be a sin plified version of the type disclosed in copending application Serial No. 438,398, for Scanning devices, filed April 10, 1942, in the names of Hail Langstroth and Fred C. Wallace, now Patent 2,407,305 granted September 10, 1946. The radiator described in that application is adapted to iirst perform a spiral scanning motion for searching purposes, and then perform a conical scanning motion for tracking purposes. The spiral scanning is accomplished by rotating the radiator about a spin axis and at the same time nodding the parabolic reflector at a slower rate about a nod axis perpendicular to the spin axis. The conical scanning is accomplished by simply stopping the nodding motion at a small angle from the zero nod position of the reflector, while continuing to rotate the radiator about the spin axis. Since in the present invention it is only required to produce conical scanning for tracking purposes. the axis or the reflectorgmay be permanently offset at a slight angle from the spin axis. In this case. therefore, no mechanism is required to produce a nodding motion.

The radiator I4 is shown in Fig. 1 in simplified form in order to clarify the basic mechanism. As there shown, a parabolic reector I5 is mounted on a hollow supporting column I6, which column in turn is supported upon a rotatable base (not shown). Column I6 and reector I5 are adapted to be rotated about a spin axis I1 by the fixed motor I8 through gearing I9 and 2U. Because of the bend in column I6, the axis 2i of the reflector I5 will then describe a cone about' spin `axis I1, thus providing the required conical scanning. It will be understood that the radiator I4 is mounted in the aerial torpedo I so that the spin axis I1 coincides with the axis of the aerial torpedo.

The rotation of column I6 and reflector I5 about the spin axis I1 is transmitted, as by gearing 22 and shaft 23, to a two-phase generator 24 which is adapted to produce on its output leads 25 and 2E two 90 phase-displaced alternating current voltages, thus providing a time reference for the spin motion. In this way,'the inatraco? stantaneous'magnitude of the voltage 2t may be made to correspond at any time to the elevational component of the angle that the reector axis il makes with the spin axis Il. Similarly, the instantaneous magnitude of the voltage 25 corresponds to the azimut-hal component of that gie.

The ultra high frequency pulses, originating in pulse transmitter i2 and propagated along the wave guide I3, enter the radiator lli through the cylindrical wave guide 2l. They are then transmittecl` to the defiecting plate 3.0 through the rotating joint 28 and a second cylindrical Wave guide 29 mounted concentrically within the hollow column i6. The deecting plate 30 is adapted to interchange energy with the reector i5 so that a fan-shaped beam of electromagnetic energy is intermittently projected into space along the axis 2i of the reflector i5. Thus, as the reector l5 spins about the axis i'i, the electromagnetic energy is irradiated into a solid conical angle oi space.

Radiator it serves also to receive energy reflected from remote objects during the intervals between successive transmission periods. The received energy passes in reverse direction through the wave guides associated with the radiator le. A wave guide i3' connected with the Wave guide 2l conducts the received energy through a limiter 3d and Wave guide 35 to a receiver and detector 36.

The limiter 3d prevents the high-powered transmitted pulses from affecting the receiver, while allowing the relatively weak received energy to pass through with little attenuation. This limiter may be of the gaseous discharge type known to the art, which consists of a gas-filled resonant chamber containing electrodes and maintained close to the ionization point. The limiter is adapted to discharge when strongly excited by the transmitted pulses and thus eiectively clamps the exciting oscillations. The electrical length of the wave guide i3 is adjusted to reflect a very high impedance to the transmitted pulses at its junction with wave guide i3 when the transmitted pulses, upon attempting to pass through the limiter, discharge the resonant chamber 'and create substantially a short circuit therein.

The receiver 36 amplies and detectsv the received pulses in the usual manner and transmits the detected pulses to the detector and filter 3l, as by lead 98. To further insure that no transmitted pulses directly aect the receiver, suitable blanking pulses may be furnished, as on lead in, from the pulse generator i0 in order to biasrthe receiver to insensitivity for the duration of the transmitted pulses.

As more completely described in the aforesaid copending application Serial No. 441,188, should an object or a target be within the range of the conical scanning performed by radiator M, a reflected pulse will be received back corresponding to each transmitted pulse. Also, these reected pulses will vary in amplitude at the spin frequency, the maximum amplitude occurring at the time that the reflector axis 2l most nearly coincides with the line of sight to the target, and the amplitude of the spin frequency variation being proportional to the amount of angular deviation ofthe line of sight with respect to spin axisy il. Thus, the detected pulses appearing on lead 38 provide an inherent indication of the amount and direction of the angular deviation oi the line of sight to the target with respect to the spin axis l1.

The detector and filter 3l is adapted to produce on output lead il a spin frequency voltage corresponding to the envelope of the pulses appearing on lead 38. This spin frequency voltage il is transmitted to the elevation phase sensitive ampli- Iier 42 and the azimuth phase sensitive amplier 43, as on leads 44 and B5. respectively.

The elevation phase sensitive amplifier 42 is adapted to compare the phase of the voltage received on lead M with the elevation reference voltage received on lead 26, and to produce on output lead 6 a direct voltage corresponding in polarity and magnitude to that component of voltage dll, which is in phase with the reference voltage 26. In a similar manner, the azimuth phase sensitive amplier 43 produces on output lead l a direct voltage corresponding in polarity and magnitude to that component of the voltage 45 which is in phase with the azimuth reference voltage 25. Thus, it will beseen that the voltages produced on output leads 6 and l correspond in polarity and magnitude to the elevation and azimuth components, respectively, of the error angle, that is, the angie that the line of sight makes with the spin axis il and consequently with the axis of the aerial torpedo l.

The elevation error signal voltage on lead 5 is amplied in elevation amplifier 46 and then transmitted, as on lead 41, to the elevator servo system t8. Similarly, the azimuth error signal voltage on lead 'l is amplied in azimuth amplifier 49 and transmitted to the rudder servo system 56, as on lead 5l. The rudder servo system 50 may be of the type shown and claimed in the allowed application of Carl A. Frische and Gerald N. Hanson, Serial No. 206,984, led May 10, 1938, for Aircraft automatic pilot with automatic banking, which has matured into Patent No. 2,380,425, granted July 31, 1945.

In Fig. 3 there is illustrated a suitable type of rudder and elevator servo system. As has previously been pointed out, the amplifier 66 is adapted to produce in its output lead lil a reversible polarity direct voltage. This voltage dl controls a suitable torque motor 52 of any conventional type adapted to produce an angular displacement of its output member 53 in a direction and of a magnitude corresponding to the polarity and magnitude of the control voltage il.

As shown, output member 53 may be centralized by suitable springs 54 which also assure a linear and a proportionate type of control. Output member 53 is adapted to reciprocate the control piston 55 of a suitable control valve 56 which is supplied with hydraulic or pneumatic pressure from a suitable pump (not shown), as by duct 5l, and is connected to a return reservoir or sump by a duct 58.

Valve 56 is adapted to produce between its output ducts 59 and 60 a differential iiuid pressure corresponding in sense and magnitude to' the relative displacement between its piston 55 and its iixed housing 6|. This differential pressure is led to a servo motor 62 having a movable piston 53 and a fixed housing B4. The differential pressure causes piston 63 to move, thereby causing the rack member 65 to be displaced at a velocity proportional to the displacement of control piston 55 and, therefore, also proportional to the control voltage in

leads

41 and 6.

It will be understood that the type of servo system illustrated in Fig, 3 could be replaced by any suitable type of servo system adapted to produce a displacement of rack 65 at a velocity proportional to the control voltage d1. If desired, a servo system employing well-known anti- T hunt and anti-lag features couldbeused. The

rudder servo system 88 operates in a similar way to produce a displacement of its output rack member 68 at a velocity proportional to control voltages I and 1. I

The displacement of rack 68 is transmitted through the pinion 81 to the pulley system 68 which controls the movement of the' elevator control surface 2 of theaerial torpedo I, as schematically indicated by the dash line 68. Similarly, the displacement of rack 86 is transmitted through the pinion 18 to the pulley system 1I which, as indicated schematically by the dash line 12, A'controls the rudder control surface 8. The aerial torpedo I is schematically shown as having its ailerons controlled automatically from the 4rudder control system 1I, 12 through the control device l13. The control device 18' is adapted to modify the rudder control displacement so as to provide the-control displacement for th'e ailerons 8 necessary to produce the proper banking angle for the aerial torpedo I.

If desired, a separate and independent banking angle control for the ailerons could be provided. Such a control could consist of a servo system and associated equipment similar to the elevator servo system 48, and also a pendulum device for controlling the servo system. The pendulum device would be of the well-known inductive pickoi type adapted to produce a control voltage corresponding in sense and magnitude to the banking angle error.

`In Fig. 4, the angular relationship of the aerial'torpedo I with respect to its carrier aircraft. 15 and the target 18 during successive stages of its actual operation is illustrated. The carrier aircraft 15 may be provided with data indicative of the orientation ci the line of sight with respect tothe aerial torpedo, from the radio sighting means mounted on the aerial torpedo, as will be more fully described hereinafter, or it may be equipped with its own sighting means. which may be either of the radio or optical type. Having picked out a target, the pilot then flies the carrier aircraft 'I5 toward the target, thereby aligning both the 'axis of the carrier aircraft and that of the aerial torpedo I with the line of sight. The pilot then, having energized the control apparatus mounted on the aerial torpedo I" by switching means (not shown), releases the aerial torpedo by suitable release mechanism,

' schematically indicated at SII, which may be`of the type commonly used for releasing bombs or ordinary torpedoes.

Thus, the aerial torpedo I will have an initial direction of motion imparted to its substantially along the line of sight to the target 16. Accordingly, the targetwill initially be located within the solid conical angle scanned by the radiator I8, and the control apparatusmounted on the aerial torpedo will. operate to maintain the axis of the torpedo coincident with the line of sight through` .ray indicator tube 88 is placed under the control of the received pulses, as by lead 38', which is connected to lead 38 on the aerial torpedo. It

.will be remembered thatl a voltage pulse appears on lead 38-each time a reflected pulse is received out the subsequent ilight, in the manner pre- 4 by the reflector I5. The cathode ray tube 88, which is normally biased omis biased on by the voltage pulse received on lead 38 and applied to Thus the electron stream is momentarily allowed to pass each time a reflected pulse is received.

The elevation and azimuth error signal voltages which appear on leads 8 and 1, respectively, of 1, are transmitted to the carrier craft, as by leads 8' and 1', and are applied to the vertical and horizontal deecting' plates 82 and 88, respectively, of the cathode ray tube 88.

In order to obtain a rough range indication there is superimposed upon the horizontal deiiectlng plates 88, as by lead' 84, a rapidly oscillating voltage which is initiated at the time pf the transmitted pulse and decreases in' amplitude with time.V This voltage may be obtained from a suitable range wings" circuit 86 which is fed with pulses from the pulse transmitter I2 of Fig. 1, as by lead 88. A range wings" circuit suitable for this purpose is fully described'in previously mentioned copending application Serial No. 441,188. y

l The presentation appearing on 'the face of the cathode ray tube 88 is of the character shown in Fig. 6, wherein the position of the dot 81 with respect to the center of the face represents the angular orientation of the line of sight to the target with respect to the axis of the aerial torpedo. T-he length of the range wings 88 caused by the oscillating voltage from the "range wings" axis of the aerial torpedo I with the line of sight.

Upon release of the aerial torpedo, it will automatically maintain itself oriented along the li'ne of sight and eventually strike the target, as previously explained.

The leads interconnecting the aerial torpedo I and the carrier aircraft 15 may each bel terminated at a plug (not-shown) which may be located on either the torpedo or the carrier craft, and which is adapted to easily pull apart upon release .of theI aerial torpedo I.

Since many changes could be made in the above `construction and many`apparently widely different embodiments of this invention could be made without departing from the scope thereof, it is intended that all matter contained in the above description rshown' in the` accompanying drawings shall be 'interpreted as illustrative and not in a limiting sense. In particular, it will be understood that the principles of. the invention are not limited to an aerial torpedo. it being obvious that any explosive-bearing and steerable body, whether designed for navigation in the air, on land or on water, could be equipped with apparatus similar to that disclosed in the present application.

What is claimed is:

l. In a device of the character described comprising a glider aircraft bearing a high explosive charge and equipped with elevator and rudder control surfaces for orientation of said craft in elevation and azimuth respectively, a radiant energy reected-pulse radio system for dening a line of sight to a target, said system including means for generating periodic pulses of electromagnetic energy, a reflector for directively radiating said energy pulses into space in a fanshaped beam along the axis of said reflector, said reflector axis making a small angle with the craft axis, means for rotating said reector about the craft axis, whereby a solid conical angle of space is scanned with said energy. means for receiving the corresponding energy pulses reected from a target located within said conical angle and means for interpreting the phase and amplitude of the variations in intensity of said reflected pulses and for producing elevation and azimuth signal voltages corresponding to the elevational and azimuthal components, respectively, ci' the angular displacement of the line of sight to the target with respect to the craft axis, servo control means for actuating said elevator control surface in response to said elevation signal voltage, and additional servo control means for actuating said rudder control surface in response to said azimuth signal voltage, whereby the orientation of said craft is continuously maintained coincident with the line of sight to said target.

2. An aerial torpedo, as claimed in claim l, wherein said glider aircraft is also equipped with aileron control surfaces and a control device for operating said surfaces, said control device being actuated from said rudder servo control means, whereby the proper angle of bank is provided during turning of the craft.

3. Apparatus for striking a stationary or moving target with a high-explosive charge, comprising, in combination, a target-seeking glider torpedo containing said explosive, sighting means for defining a line of sight to a target mounted on said torpedo for continuously obtaining error signals indicative of the non-coincidence of the axis of said torpedo with respect to the line of sight to said target. indicating means responsive to said error signals, for initially aligning the torpedo axis prior to release with ,the line of sight, and automatic positioning means responsive to said error signals for continuously maintaining the axis of said torpedo directed on the sighted target after the release of said torpedo.

4. Apparatus for striking a stationary or moving target with a high-explosive charge, comprising a target seeking glider torpedo containing said explosive, radio sighting means for defining a line of sight to a target mounted on said torpedo including generating means for producing periodic pulses of electromagnetic energy, directive radiating means for projecting said energy pulses into a solid conical angle of space, the axis of said conical angle coinciding with the axis of said torpedo, means for receiving the corresponding energy pulses reected from a target located within said solid angle and means for interpreting the variations in intensity of said reflected energy and producing voltage signals proportional to the angular deviation of the line of sight to aaoov said target witfnrespect to the orientation of said torpedo, indicating means responsive to said voltage signals, for aligning the torpedo axis initially and prior to release with the line of sight, and automatic positioning means responsive to said voltage signals for continuously maintaining the axis of said torpedo coincident with the line of sight to the target after release of said torpedo.

5. Apparatus, as claimed in claim 4, wherein said indicatingv means consists of a cathode ray tube, said voltage signals being applied to the horizontal and vertical deilecting plates of said tube, and further including means responsive to the time delay between said radiated pulses and the corresponding reflected pulses for providing on said cathode ray tube an indication of target range.

6. A self-controlled projectile adapted to steer itself into a station-ary or moving target, comprising a, steerable projectile, radio sighting means comprising generating means for producing periodic pulses oi electromagnetic energy mounted on said projectile, directive radiating means for projecting said energy into a solid conical angle of space, means for receiving the corresponding energy pulses reflected from a target located within said solid angle, and means for interpreting the variations in intensity of said reflected energy and producing voltage signals proportional to the angular displacement of the line of sight to said target with respect to the axis of said radiating means, and automatic control means responsive to said signal voltages for continuously realigning the axis of said radiating means with the 'line of sight.

'7. An aerial torpedo adapted to steer itself into and explode against a predetermined target, comprising a glider aircraft carrying an explosive cli-arge, a radio sighting means comprising generating means for producing periodic pulses of electromagnetic energy, directive radiating means for projecting said energy pulses into a solid conical angle of space, the axis of said conical angle coinciding with the axis' of said glider, means for receiving the corresponding energy pulses reiiected from a target located within the solid angle, and means for interpreting the variations in intensity of said reected energy and producing voltage signals proportional to the angular deviation of the line of sight to said target with respect to the orientation of said glider, and automatic control means responsive to said signal voltages -for continuously reorienting said glider into coincidence with said line of sight.

8. A target seeking torpedo of the glider type, means mounted thereon for dening va line of sight -to a |target including an antenna, -a transmitter therefor for projecting spaced signal impulses toward a target, .a receiver operatively connected with the antenna responsive to said impulses when reflected back to the antenna from a target, an indicating device controlled by the receiver responsive to the received reected irnpulses to aid in initially positioning the torpedo with reference to a target, and means controlled by the receiver in accordance with the reflected impulses on the launching of the torpedo for guiding the latter towards the target.

9. A target seeking torpedo comprising a glider aircraft bearing a high explosive charge and equipped with elevator and rudder control surfaces for orientation of said aircraft in elevation and azimuth respectively, radio sighting means mounted on the aircraft for defining a line of sight to a target including a rotary antenna, an

impulse transmitter and a receiver for receiving the transmitted impulses on reflection from the target, means jointly controlled by the receiver and the antenna according to the instantaneous angular position thereof ior continuously obtain ing error signal voltages indicative of the elevational and azimuth components, respectively, of the line of sight to the target with .respect to the orientation of the axis of said aircraft, servo control means responsive to said elevation error signal voltage operating on said elevator control surface to orient the axis ot said aircraft into coincidence with said line of sight in elevation. additional servo control means responsive to said azimuth signal voltage operating on said rudder control surface -for orienting the axis of said aircraft into coincidence with said line of 'sight in azimuth, aileron control surfaces for the alrcraft, and a control device for operating the latter surfaces actuated from the rudder servo control 20 means, whereby the proper angle o! bank is provided durlng turning of the aircraft.

WALDEMAR A. AYRESV.

' REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Great Britain July 16, 1942 Certiicate oi Correction Patent No. 2,448,007.

August 31, 1948.

WALDEMAR A. AYRES It is hereby certified that errors appear in the printed-specification of the above numbered patent requiring correction as follows:

Column 9, line 7, claim 1, strike out the word In; same line, for a device read A device;

and that the said Letters Patent should be read with these corrections therein that the same may conform to the record of the case 1n the Patent Oilice.

Signed and sealed this 5th day of April, A. D. 1949.

THOMAS F. MURPHY,

Assistant 'ommssoner of Patente.