US2466528A - Dirigible bomb - Google Patents

Description

R. D. WYCKOFF ET AL.

Aprii 5, 1949.

DIRIGIBLE BOMB 8 Sheets-Sheet 1 Filed May 31., 1946 flmwc nfwps RELPH D. WYCJKOFF JULIUS P. MOLNBR LOYAL 'D. P'ALMER G (JV C. BLEWETT April 1949- R. D. WYCKOFF ET AL 2,466,528

DIRIGIBLE BOMB Filed May 51; 1946 s Sheets-Sheet 2 N 111 FL ALPH nwvcxoFF JULIUS P. MOLNAR LOYAL D-PAJLMER GUY (LfiJJElWjECTT April 5, 1949.

R. D. WYCKOFF ETAL DIRIGIBLE BOMB 8 Sheets-Sheet 3 Filed May 31. 1946 gmtz/wboms RALPH D.WYCKOFF JULIUS F? MOLNAR 11 P LMER GUY c. BLEWE April 1949' t R. D. WYCKOFF ET AL 2,466,528

DIRIGIBLE BOMB Filed May 31, 1946 8 Sheets-Sheet 4 SELF BALANCING 5 310 2512 7 I51? {EQNNECIIQN RADIO RADIO 7 PULSE RUDDER TRANSMITTER g gwgg "415 RATCIR *Acrumrm A0 -RADIO RADIO TRANSMITTER RECEIVER OSCILLATO OSCILLATOR Fl. FR f [77% 'RUDDER g ACTUATOR '21 721? 72. u

glwucnfoos RALPH D. WYQKOFF JULIUS P. MOLNRR J- YAL D. PfiLMflR GUY C. BL EZTT April 5, 1949.

Filed May 31, 1946 R. D. WYCKOFF ETAL DIRIGIBLE BOMB 8 Sheets-Sheet 5.

April 5, 1949. R. D. WYCKOFF ET AL 2,466,528

' DIRIGIBLE BOMB Filed May 51, 1946 8 Sheets-Sheet "7 RBI- PH D. WYCKQFF $5. m; O 2- April 5, 1949;

D. WYCKOFF ETAL DIRIGIBLE. BOMB Filed May 31. 1946 8 Sheets-Sheet '8 Patented Apr. 5, 19 49 DIBIGIBLE BOMB Ralph D. Wyckoif, Pittsburgh, Pa., Julius 1'. Mol- Morris Plains, N. J and Loyal D. Palmer,

Oakmont, and Guy C. Blewett, Penn Township Allegheny County, 2a., assignors to Gulf search & Development Company, Pa., a corporation of Delaware Be: Pittsburgh,

Application May 31, 1946, Serial No. 673,374

2 Claims.

This invention relates to dirigible bombs and particularly to a remotely controlled so-called high angle bomb having a relatively stable trajectory bearing a general similarity to that of a freely falling bomb as distinguished from gllding bombs, for example, which approach the target at a low angle.

In order effectively to accomplish military bombing from aircraft, it is necessary to have a high percentage of target hits. Numerous aiming techniques have been employed to improve bombing accuracy and at the present time this has reached a fairly high state of development.

When a bomb is dropped so as to fall freely from a plane, various factors are known to effect its sideration of the known factors involved, a certain amount of scattering occurs due to unpredictable and uncontrollable effects. Some of these effects are aerodynamic, some mechanical, and some atmospheric. I

It has been found desirable to steer an otherwise freely falling bomb so as to correct for inaccuracy in aiming and to correct for unforeseeable effects encountered by the bomb in flight. In spite of the relatively high terminal velocities attained by high-angle bombs, we have found that aerodynamic steering of such bombs in flight is both feasible and effective. Bombing accuracy has thereby been improved considerably.

This invention concerns a form of steerable bomb remotely controlled from the bombing plane by radio. Inasmuch as the bomb-sight is dea hit anywhere along the length of the target becomes effective. y

In the making of a steerable high-angle bomb, a number of factors must be taken into account. Means for producing aerorynamic deflecting forces'must' be added to the bomb in the form of aerodynamic lift surfaces. In addition, steering surfaces must be provided tomaintain the angle of attack of these surfaces required for the production of deflecting forces. In order to maintain the effective direction of the steering controls, that is, to the right or left, it is necessary to stabilize the bomb against roll rotation.

Furthermore, stability in flight'mus't be maintained to avoid undue oscillation and gyration of the bomb. In addition, a number of practical considerations are involved; namely, structural strength must be sufficient to handle the ,aei 0 .dynamic forces required, the device must fit into already available component parts and preferably permit interchangeability, and in addition space requirements should be reduced to a minimum and kept within that permitted on military aircraft.

Military requirements dictate that the bomb must be capable of being-accurately guided to the desired target, such accuracy being as high as possible. By means of our invention an error smaller than 10 ft. may be attained for 15,000 ft. altitude. This requires a degree of maneuverability which, in turn, demands that the aerodynamic surfaces -develop suflicient lift forces to produce the required path deflection; that is, the maneuverability determines the lift which the bomb must generate when yawed at a preferred maximum trim angle with respect to its lineof flight. The aerodynamic surfaces used to produce the required lift forces generally take the form of crossed tail fins. These may be provided with movable flaps or tabs which are controlled to set up the necessary attitude in flight.

Practical military requirements dictatefactors which are not all compatible with the aerodynamic requirements- Space available on military aircraft is limited, and the bomb must be carried in the internal bomb bays of standard bombing. planes. Furthermore, the fins and controlling mechanism should desirably be capable of attachment to standard bomb cases. In the dirigible bomb forming the subject of this invention,

all the necessary components are contained in a bombing plane.

cheeses the crossed-fin tail surfaces should be rotationally oriented in flight so that one pairv of co-planar fin surfaces lies in the plane of the trajectory and the other pair of fin surfaces are at right angles thereto. Thus one may obtain rightleft rudder control by applying rudders to the fins.

which lie in theplane ofthetrajectory. The

other fins may convenientlybeequipped with ailerons for maintaining roll orientation. If the bombs are carried in the bomb baysuch that these surfaces have this orientation, the bombs take upa maximum oi'space; that is, they do I not nest well in the bomb'bay. In the device forming the subject of this invention, the bomb -may be carried in thebomb bay in a position which is rotated at an angle of 45 degrees. with v the above, the bomb being'automatically brought into proper roll orientationafter it. leaves the plane'to. carry a larger number of bombs.

The efiect'oftheimproved nesting .of'the bombs in the'bomb bay permits the of the proportional control radio receiving ap- Y Y paratus ofFlg. 9 on the bomb;

transmitting apparatus on the plane which may f be'used for simpleton-oif" control;

Flg.:13 is'a block diagram of the radio receivi ing "apparatus usedin the bomb to: cooperatev v with the on-oil" control transmitting apparatus of Fig. 12;

- Fig. l4is a schematic electrical wiring diagram v v v v of the radio relaycircuit used for the on-off" control;

Fig. 15'is a schematic electrical wiring diagram v v v v i of the rudder actuating servounit used for the. on-off? control;

It is an object of thisinvention to provide a remotely controlled high-angle bomb.

. Another object of this invention is to provide a remotely controlled high-angle bomb steerable in. azimuth after release. 1

Another object is to provide a remotely controlled high-angle; bomb. having a. unitary re motely steerable tail structure which is interchangeable withthe tail structureof standard non-steerable bombs.

Another'object of thls'invention is to provide a remotely controlled high-angle bomb lof gr'eat maneuverability which may be steered in azimuth by means of a rudder. controlledin proportion to i thedesired degree of control.

Another object ofthisinvention is to provide a remotely controlled high-angle stable bomb which may be steered in azimuth by. means of a a simple on-and-oif rudder control.

Another object of this invention is to provide a remote azimuth controlled high-angle bomb having a cruciform tail structure and which may be nested in the bombing plane to take up a minimum of space. r

These and other objects of the invention are attained through the design herein specified. Reference is made to the drawings forming a part of this specification, and in which Fig. 1 is a perspective view of the bomb provided with the novel tail assembly comprising this invention;

Fig. 2 is a perspective view of the tail structure removed from the bomb and showing also the modeof mounting onthe bomb and construction details of the housing;

Figs. 3 and 4 are side and rear views, respectively, of the tail structure showing for clarity only the rudder actuating mechanism;

Figs. 5 and 6 are side and rear views, respectively, of the tail structure showing for clarity only the aileron actuating mechanism;

Fig. 7 is a longitudinal section through one of the aileron actuating solenoids showingthe manner in which the solenoid rotates the aileron torque rod:

Fig. 8 is a schematic diagram of one form of radio transmitting apparatus on the plane which may be used for proportional control of the rudders affecting the course of the bomb;

Fig. 9 is a block diagram of the radio receiving apparatus which may be used in the bomb to cooperate with the proportional control transmitting apparatus of Fig. 8;

Fig. 10 is a schematic electrical wiring diagram Fig. 16 is a schematic electrical wiring diagram, v v v i of a gyro-aileron control mechanism which may 'be'usedto set up and maintain the proper roll orientation of the bomb; and

Fig.1? is a schematic electricalwiring diagram of the electrical equipment on the-bombshowing the electrical relation of the various: components.v Referenceis made to Fig. l which shows the bornbinv perspective view and to Fig 2 which shows parts of the tail structure separated :forv

purpose of clarifying the assembly. A'war head A which mas/for examplabe a standard 1,000-

pound demolition type bomb.:has attached to it a box-like tail member I carrying the components used for controlling the flight path of the bomb. The front end of the box I'is attached tothe standard war head A through an adapter ring Hi, this ring having a central aperture ll (Fig. '2) which fits over the threaded extensionv Ila at the rear of the bomb and is held in place by alocking nut lib in a conventional manner.

nut ilb being tightened by a spanner wrench inserted in spanner. holes He. The adapter ring I0 is thus attached to the tail end of the war head A in the same manner as the standard nonsteerable tail fin. The outside diameter of nut Ilb is smaller than the inside dimension of box I, so that the latter may clear the nut when attached to adapter ring Ill. The rectangular box l and its associated assembly is attached to the adapter ring II) by means of screws passing through holes 911 in flanges 9 into threaded holes 91) in the ring [0. The entire assembly of box I is thus attached to a standard bomb in a simple manner.

The box I is preferably formed by suitably shaping four sheets of metal, the central portion 4 of each sheet forming a side of the box while the side portions 5 and 8 extend at angles of 45 degrees and together with the parallel adjacent portions of the proximate sheet form the cruciform tail fins. The sheets are held together to form thebox l by means of angle strips I welded to the inside corners of the structure and external fillets 8 are secured by welding or soldering beture by insulating washers 20. The uppermost and the diametrically opposite corners oi the dipole are left open-circuited by the use oi additional insulating washers aunder the bolt head Ila and the strut ends, thus forming the two sections of the dipole which are connected to a coaxial lead-in cable 43 passing through the uppermost fin to a radio receiver which will be described later and which is contained inside the box I. Alternatively for a higher frequency carrier only two struts, i9, visible in Fig. 2 may 22 is provided with stud 24 which engages-a i'orm the complete'dipole, or any or all struts may be connected as a simple T or L type antenna with the entire shell and bomb case acting as a ground member.

A transverse partition 2a is welded into the box I in approximately its middle and serves to impart additional rigidity to the box and also serves as a mounting for various actuating mechanisms and components to be described later. The

rear end of box I is normally closed by a flat cover plate 2.

The rear cover plate 2 carries a flare 3. The purpose of the flare is to permit the bombarcier to easily visually observe the course of the bomb after it is released. The war head A having a customary fuze (not shown) and arming devices (not shown), and the flare 3, are well-known devices and do not form a part of this invention a per se.

Movably attached to the trailing edge of each iln surface is a control surface such as i2 and 29. These are made of spaced metal sheets continuously bonded by welded at their edges and pivotally mounted by means of torque rods i3 and 39 extending therethrough. The manner by which control surfaces 12 and 29 are actuated through torque rods i3 and 30 will be described later. Two of the control surfaces, such as l2, act as rudders and provide right and left steering control. The fins to which rudders i2 are attached are automatically oriented substantially in the plane of the trajectory during most of the bombs fall, as will be described later. The other two control surfaces, such as'29, may serve as ailerons which provide roll orientation in a manner also to be described later. The rudder and ailerons are hinged along a line per cent behind their leading edges in order to minimize the torques necessary to rotate them in a wind stream.

Rudders i2 are mounted on rods l3 journaled at the outer end in bearings formed in extension pieces [4, these being welded to blocks l5 which may he slipped in between the two sheets forming the fin and held in place by bolts 16 and IT. The

, inner mounting of rods i3 and its actuating mechanism is shown in Figs. 3 and 4. The inner end of the rod i3 extends through an aperture in the vertical corner brace l of the box and is aligned by bearing i3a formed in transverse plates i3c which are welded to angle strips l. Connected to the inner end of each rod i3 is a crank arm I3b having a narrow open slot 13d at its outer end. A servo mechanism engaging the outer end of this crank arm controls the attitude of the rudder i2 attached to rod IS.

The manner by which the servo motor actuates the rudders i2 is illustrated in Figs. 3 and'4. A servo unit 2i having conventional step-down gearing with limiting and centering switches and crank 22, is suitably supported on a base 2 lb which may be bolted to the partition 2a inside box I. The axis of crank 22 is substantially parallel to the axis of torque rods Hi. The outer end of crank Cir driving link 26. The driving link 26 serves as a coupling link to couple the two rudder cranks lib together and with the servo'motor in a manner which eliminates any binding due to slight misalignment. Driving link 26 may comprise a rectangular bar bent into a U-shape and having bearin holes on its legs close to the bends, these bearingholes fitting over the extensions lie of of torque rods I3. Driving link 26 has at the outer end of its longer leg a narrow open slot engaged by stud 24 and at the outer end of its shorter lega stud 28. The longer leg also carries a similar stud 28 similarly located, and studs 28 engage the open slot lid of both crank arms l3b, these parts bein disposed so that when movement takes place the difference in swing is taken up by the stud sliding slightly in the slot. Studs 28 are mounted on eccentric adjustments so that slight misalignments may be corrected. The angle of travel of the motor crank 22 from its neutral position is approximately i22 while the corresponding angular travel of cranks l3b and hence of the rudders to which they are connected is an approximate :15. Electrical actuation of the motor in servo unit 2| therefore will rotate both the rods l3 in unison and thereby deflect both the rudders i2 in the same direction. The electrical control of the motor and switches in unit 2i will be described later.

The ailerons 29 are identical in appearance and I rods 30 extending therethrough and into the control box I at alternate corners to those mounting the rudders I2, the outer and inner ends of rod 38 being journaled in a manner similar to rods is already described. The inner end of each rod i3 has secured thereto a crank 3| having an open terminal slot Ma. The crank arm 3| extends into an elongated opening in the case of transverse pin 33 maintained in an elongated clearance opening in the cylindrical solenoid core 33a. The solenoid is wound with independent coils 34a, and 36b on each side of its central cross section so that selective energization will move the core longitudinally and hence cause rotation of the crank 3 l, rod 30, and aileron 29. Each solenoid is suitably mounted on a bracket 34c inside the control box i. The ends of the solenoid cores are of customary conical shape and the core is returned to center by spring-pressed pins 35 located at each end of the solenoid casing.

To coordinate the operation of the two solenoids and to insure simultaneous operation of the individual ailerons regardless of any unbalanced aerodynamic torques on the two ailerons, the rods 30 are mechanically linked together. Each rod 30 has mounted thereon adjacent its crank arm 3| a bell crank 38, cranks 3| and 38 being secured together by a bolt and nut assembly 39, one member havingan elongated hole whereby the angular relation between adjacent cranks 3i and 38 may be adjusted. Bell crank 38 has a slot 38a which engages a terminal pin 38b on a rectangular rockin beam 36, the beam 36 being mounted at its mid-point on transverse rocker pin 36a.

' Rocker pin 36a is supported in yoke 36b which is aceasas beam 36 is rocked. The rocker beam 35 thus ties together the operation of the two ailerons so as to insure their simultaneous and coordinated operation. The solenoid coils are electrically so connected and their action mechanically linked by rocking beam 36 so that the ailerons operate in opposite directions in order to produce the necessary roll torque to bring the bomb into proper roll orientation.

Radio control The bombardier in the plane may observe the course of the bomb after it is launched, the ignited tail flare 3, Figs. 1 and 2, being clearly discernible even in bright sunlight. It has been found that by visual observation, the bombardier may easily determine the direction of deviation required to bring the bomb on target. Various known methods of transmitting the necessary signals to the bomb from a radio channel may be used, two such methods being described here by way of example. The rudders for steering the bomb to left or right may be actuated by servomotor 2|, as previously stated, the energization of this servomotor' being controlled by the character of the radio signal received by the radio receiver within the bomb.

For best maneuverability it is desirable to provide a so-called proportional control system in which the angular displacement of the rudders on either side of their neutral position is correlated in proportional relation to the movement of the bombardiers control stick. In one embodiment to be described, the energization of the servomotor 2|, which controls the attitude of the rudders, is controlled by the character of pulses transmitted from the plane and received by the radio receiver within the bomb. In this system regularly keyed pulses are transmitted over the radio channel, the bombardier's control stick varying the length of the carrier's pulses. Thus when the on time is equal (or of predetermined ratio) to the off time. neutral control ,is obtained. An increase in the off time and decrease in the on time effects control in one sense, whereas a decrease in the "ofi" time and increase in the on time effects control in the opposite sense.

One form of this system is described with reference to Figs. 8, 9, and 11. The regularly keyed pulses transmitted over the radio channel are integrated in the radio receiver on the bomb. The carrier is keyed on and off, and when the time on" is roughly equal to the off time the system is in its neutral position. Control is ob-' tained by increasing or decreasing the on time relative to the off time. The manner in which the transmitter is keyed is illustrated diagrammatically in Fig. 8. Numeral 300 is a control stick pivoted at point 30l and returned to a center position by springs 302. Connected to control stick 300 is link 303 which moves insulating block 304 sliding horizontally in guides 305. Mounted on insulating block 304 are two contact springs 306 and 301, spring 30'l being equipped with an insulating follower 308 which bears against eccentric disc 300. Eccentric 300 is driven by motor 3) at a nominal speed of about 1000 R. P. M. Adjustment of the contact points 306 and 301 is made such that the contact is closed approximately throughout half the revolution and open throughout approximately the other half of the revolution. The contacts are connected by wires 3 to the keying circuit of radio transmitter 312 whose signal is radiated from antenna 3l3 on the bombing plane. By this means an interrupted carrier signal is transmitted, the relative length of on and "off" periods being under the control of lever 300 in the hand of the bombardier.

Fig. 9 shows the control equipment on the bomb. It comprises antenna 3M which may be the dipole made up of struts I9 (Fig. 1 Connected to the antenna is a conventional superregenerative receiver 3l5 which together with pulse integrator 3|6 supervises the position of the rudder actuator 311 in a manner to be described. The rudder, actuated through a self balancing connection, finds its equilibrium position in a manner which will become evident by reference to Figs. 10 and 11.

Referring to Figs. 10 and 11, Fig. 10 shows a conventional super-regenerative circuit employing however an unusual manner of adjustment to avoid phase reversal in the square-topped output wave of the receiver. In the simplest type of super-regenerative circuit the oscillation of the detector produces the grid blocking which quenches the detector. This means that the detector grid is biased too near the cut off 'end of the characteristic curve of the tube. On strong signal the detector changes from grid detection to plate detection. Since these two types of detection are opposite in phase, a phase inversion of the received impulses results on changing from very, strong signals to normal intensity. In applications of this circuit to remotely-controlled apparatus, as a radio-directed bomb, the latter must be operated over a range from a few feet to some thousands of feet from the transmitting antenna and the phase inversion described above would therefore impart a false movement to the control surfaces of the bomb. Consequently, a simple super-regenerative circuit cannot be empioyed.

Beginning at the left of Fig. 10, a conventional radio frequency amplifier using tube 350, which may for example be a type 9001, is connected to the receiving antenna and to the detector tube 35L for example a type 9002, through coils Lo and L4. The radio frequency stage is necessary due to the fact that the super-regenerative circuit is critical to antenna loading and hence must be isolated from the antenna. The radio frequency stage also provides some additional signal amplification and minimizes reradiation iof the energy originating in the oscillating detec- A separate "quench" oscillator utilizing tube 352, for example a type 655, and appropriate coils L5 for the optimum quench frequency, (much lower than that of the detector circuit frequency) is connected to the detector 3! to trigger the latter into oscillation. The quench oscillator 352 is capacitatively coupled by adjustable ca pacity 353 to the grid circuit of detector 35l and operates to vary the detector grid voltage to cause the detector 35I to oscillate at a rate determined by the constants of the quench oscillator circuit. The adjustment of the detector circuit 35! is such that in the absence of energy from the local oscillator there is no oscillation of the detector at signal frequency.

Tubes 354 and 355 of Fig. 10 may be of the type 6SN'7 and comprise an amplifier circuit of conventional resistance-coupled type but resistances and condensers having long-time constants are employed in order to preserve the square-topped wave-form for which the receiver is particularly designed. The wave-form is comedusa of regularly-keyed voltage pulses, the

which moves the control surfaces on the bomb.

The square-topped voltage pulses from the resistance-coupled'amplifier are utilized as follows.

The amplified square-topped voltage pulses are applied to the grid of the first section 353 of a twin-triode vacuum tube. By using large input voltages the grid is driven between two limits,

the negative cut-off and saturation, and so the average voltage at the plate 331 of this section is determined within limits, by the pulse length. The average plate voltage is filtered by the resistance-capacity circuit comprising condenser 333 and resistors 333 and is directly coupled to pends upon the grid bias of tube 33L which in turn. depends on the pulse length applied to the input. In Fig. 10 the filament supply is conventional and is omitted for clarity. Terminals 335 are connected to voltages as shown on a conventional power supply.

When the relay is open, the motor 2| (Figs. 3 and 4) for moving the rudder surface runs in one direction and when the relay closes, the motor goes in the opposite direction. Further details i0 direction of rotation of the motor. The latter turn is governed by the energization of relay 323 (Figs. 10 and 11). Limitswitches Hi and 322 are positioned to limit the maximum amplitude of rudder movement on either side of a central position.

In the motor circuit of Fig. 11, it is apparent that when power is applied tov the terminal 323,

{it energizes shunt field 323, the circuit returning to the ground through terminal 321 and wire 323. The 24 v. power also energizes field coil 323 and wire 330 and it is apparent that energization of relay 323 will cause the. motor armature 33| to rotate in one direction, while energization of relay 324 .will cause the motor to rotate in the opposite direction through reversal of the current flow of the armature with respect to the field winding as is well known. The return current is .via wire 332, 333 to 321 and ground. The energization of relays 323 and 324 is determined by the position of relay 323. when relay 320 is balanced so that it chatters between its contacts, the motor armature 33| remains at rest. However, if the relay 320.conta'cts 334, power fiows from the 24 v. supply through field 323. wire 333, relay coil 323, limit switch 32L contact 334' to ground via wire 323. If relay 323 contacts 333, current flows in a similar way through relay 324 and limit switch 322 through contact 335 and wire 323 to ground. The

as to the operation of relay 323 will become ap parent in the explanation of Fig. 11 to' follow. In order. that the rudders be held in anequilibrium position corresponding to the desired angle, 1. e., pulse length, the motor 2| rotates a high resistance rheostat 333 (Fig. 10) which is connected to the grid circuit of the relay tube 363 and in so doing changes the bias on this tube. The rheostat 363 is mechanically coupled to motor 2| (Figs. 3 and 4) through connection 364 of .Fig. 10. (This connection is conventional and is not shown on Figs. 3 and 4). Electrical terminals 321, 334,335 connect to the rudder motor as shown in Fig. 11. Thus, the circuit responds essentially.

as an automatically balancing potentiometer, which measures avoltage that can be controlled directly by varying the length of the pulses applied. By choosing the proper values for the circuit constants, the motor response can be made substantially a linear function of the pulse length over the range required.

The successful operation of this circuit depends on the existence of suific'ient A.-C. ripple in the grid voltage applied to the second stage, so that the relay 320 in the plate circuit chatters near the balance point. In this way diificulties with relay hysteresis are eliminated. The amplitude of the A.-C. ripple can be controlled by the R. C. constant of the filter circuit. For optimum operation the amplitude should be limited to a value which permits relay chatter only when the motor is within a few degrees of the balance point. As

will be evident, the ripple amplitude required depends on the difierence betweenthe pull-up and release threshold current of the relay.

Fig. 11 is a wiring diagram of the servomotor and reduction gear unit 2| which is connected to actuate the rudders. Devices of this character are well known, being used extensively in aircraft I limit switches Hi and 322 merely serve to open the relay circuit when an extreme position of the crank arm infeither direction is reached.-

trol of the rudders. In this system the rudders are either full on or full on, and in the absence of control. return to neutral. The bombardier applies left rudder or. right rudder as desired for a time which he estimates will correct the devialators having frequencies F1. and Fa, each modulating the transmitter 40 at its characteristic audio frequency when its respective key'42 and 44 is pressed. The frequencies F1. and Fa may conveniently for example be 475 and 1000 cycles/sec. Thus the bombardier has two push buttons 42 and 44 which control the oscillators Fr. and Fa to modulate the radio wave transmitted to the bomb. The controlling radio wave therefore comprises a carrier frequency modulated by an audio frequency appropriate to the direction of deviation which the bombardier desires to impart to the bomb.

Fig. 13 is a blockdiagram of one form of radio receiving equipment carried on the bomb and used for responding to the steering signals from the plane. Here 46 represents the dipole or other type antenna made up of the struts l3 (Figs. 1 and 2). Connected to the ends of the dipole is the coaxial cable 43 (Fig. 1) leading to conventional radio receiver 41, including a demodulator which delivers audio signal to two filters L and R. These are narrow band-pass filters of known type and when an appropriate signal is received,

it is passed on by the agency of relays (which will 'be described later) to rudder actuator 2|, which in turn deflects the rudders I2 in the proper sense. In the above form of control here described, only "on-off control is obtained, the rudders returning to neutral in the absence ofany audio signal. If the bombardier, for example, desires to apply left rudder he may close contact 42, Fig. 12, and thereby modulate the radio signal at a frequency FL- The receiver 41 picks up this signal, and passes on a frequency F1. to the filters L and R. As the frequency F1. may only pass through filter L. relay L is energized and there is applied to the rudder actuator power to drive it and the rudders into the leftwise position. If neither of the contacts 42 or 44 are closed by the bombardier, the rudder actuator automatically returns to its neutral position as described later.

The operation of relays L and R of Fig. 13 is shown by the wiring diagram of Fig. 14 in which numerals I I3 and H4 represent the plate connection of the last tube in the audio filters L and B, respectively. Each of the plates I I3, II4 are connected through a relay coil I I1 and I I8 to a common high potential terminal I2I leading to the radio plate powersupply on the 'bomb. Armature contact springs I22 and I23 are normally connected to the righthand contact as shown in Fig. 14. Upon transmission of a signal. through the audio filter the center spring of the relay is drawn over to the lefthand contact. Thus if no steering signal is applied the relays will be in the position shown in Fig. 14. The circuit diagram shows how the contacts and springs are connected to the terminals I28 to I32. Terminal I32 is connected to ground. Terminal I3I is connected to 24 v. power supply. If the bombardier applies a signal of a proper frequency to actuate the filter L (left), relay II1 pulls contact I22 to the left. This grounds terminal I28 through left contact I22, wire I40, right contact I23 and wire I. At the same time the ground on center connection I29 is broken at I22. Similarly, if the bombardier applies a signal to actuate the filter R (right) relay II8 pulls contact I23 to the left. This grounds terminal I30 through left contact I23 and wire I4I, while at the same time the ground on center connection I29 is broken at I23. Keeping in mind that the application of steering signal merely grounds the appropriate terminal on the rudder actuating mechanism, we shallnow describe this mechanism.

Fig. 15 is a schematic wiring diagram of the ceived the actuating motor automatically returns the rudder to the center position. Right rudder signal moves the rudder to the extreme right positlon. etc. To assist in executing these movements,

the arm 22 of Figs. 3 and 4 operates through appropriate cams to switches I52 and I53 of Fig. '15. Numeral I52 represents a limit switch mechanically so arranged that when the motor arm 22 reaches its extreme right position contact I52R. is mechanically opened. 0n the other hand when the motor arm reaches its extreme left position contact I52L is opened. In all intermediate positions of the arm 22 both contacts I52L and I52R are closed. Another cam on arm 22 operates a centering switch I53. Contacts on this switch are so ar1:.nged that they are both open over a very small region at the center position. Contacts I53R and I53L are closed, respectively, when the arm 22 is off center to the right or left, respectively. Relay coils I10R and I10L when energized move contacts "I, I12, I13 and I14 to the left. Contacts l1I, I12, I13 and I14 are returned to the right hand position by springs I15 when the relay coils are deenergized. Terminal I54 is connected to the 24 v. power supply. Terminal I55 is the ground connection and terminals I28. I29 and I30 go to the radio relay (Fig. 14) previously described. Bearing in mind the mechanical operation of switches I52 and I53 and of relays NOR and I10L, and the fact that radio control merely grounds the desired terminals I28, I29 or I30, we shall now describe the operation of the actuating mechanism of Fig. 15.

We shall assume that the rudders are in a center position so that the contacts I53L and R are both open, contacts I52L and R are both closed, such being the situation when no signal is applied. Upon the application of left rudder signal radio relay II1 (Fig. 14) will ground terminal I28 (Figs. 14 and 15). Current then flows through the circuit of Fig. 15 as follows: 24 v. current enters through wire I54, contacts I52L, wire I16, relay coil I10L to ground via wire I56. This holds contacts "I and I 12 to the left and the current flows from wire I54, wire I11, wire I18, contact I13, contact I14, wire I19, wire I downward through motor armature I50, wire I8I, wire I82, contact I 12L, wire I83, contact I1IL, wire I84 and wire I55 to ground. At the same time the current flows from I54 through I11 and I18 to the motor field I5I, wire I85 and wire I55 to ground. The motor subsequently rotates to push the rudders to the left until the'left limit is reached, whereupon arm 22 (Figs. 3 and 4) opens contact I52L thereby releasing contacts "I and I12 to cut off the motor. .The motor will remain in this position as long as left rudder signal is being applied; namely as long as terminal I28 is the only one-grounded. If, however,

through I54, contact I52R, wire I88, relay I10R,

wire I81, wire I88, contact I53L, wire I89 to ground. This closes relay I10R moving contacts I13 and I14 to the left. Current may now flow through the motor armature as follows: wire I34, wire I11. contact "I, wire I83, contact I12, wire I90, wire I8 I, upward through armature I50, wire I80, wire I92, contact I14L, wire I93, contact I13L. wire I85 and wire I 55120 ground. This causes right hand rotation of the motor until the center is reached whereupon contact I53L opens. This breaks the circuit through relay I10R. releasing contacts I13 and I14 and shutting off the motor. The application of right rudder grounds terminal I30 and removes the ground from terminal I 29 and the subsequent operation of the device is very similar to that when left rudder is applied, except that direction of the current flow in the armature is such as to produce right hand rotation. If after the application of right rudder, the steering signal is removed, the motor returns to center in essentially the same manner as above described. It the bombardier desires to do so he may apply right rudder immediately after the .application of left rudder or vice versa, in which ance may be connected across relay coils I'IOR and I'IOL in order to reduce sparking and radio interference when contacts open the relay energizing current.

Roll stabilization In order to maintain the bomb properly orientated so that the right and left rudder controls remain identified, it is necessary to provide a stabilizing mechanism actuating ailerons which maintain such roll orientation. Accidental rolling torques may be imparted to the bomb during its fall by accidental inequalities in the tail surfaces, or during launching, or may further de-- velop due to inequalities in the steering effect of the rudders. A gyroscopic stabilizer is employed consisting of a directional gyro, so mounted that the plane of rotation of the gyro wheel is in a vertical plane of symmetry of the bomb corresponding also with the plane of the trajectory at launching. The gyro includes electrical connections to the aileron actuating solenoids so that if the bomb begins to roll in a clockwise direction, for example, the ailerons will be moved simultaneously in a direction to produce a counterclockwise restoring torque on the bomb. A rateof-turn gyro is simultaneously mounted to reverse the position of the ailerons if the rate of rolling exceeds to per second. The ailerons are thus always at one extreme position or the other, producing slight roll of the bomb about vertical orientation at a rate that never exceeds 10 per second. C

The construction of the gyro wheels and their mountings, per se, do not form the subject matter of this application. Examples are described,

in a patent application, Serial No. 543,168, filed July 1, 1944, by J. P. Molnar and A. Camvale, and also in an application, Serial No. 639,686, filed January '7, 1946, by B. E. Warren. It will suffice here to describe the electrical circuits controlled by the gyros, these being shown in Fig. 16. The direction and rate-of-turn gyros described in the above patent application of Molnar 8; Carnvale are coupled togetherin such manner that zero position on, the direction gyro varies with the displacement of the rate gyro and hence with the rolling of the bomb. The effect of this coupling as explained in the above-mentioned application is to permit a speed of rotation proportional to the displacement of the bomb from its equilibrium position and this materially improves the roll stability attained by the control.

In order to permit the bombing plane to carry a maximum number of bombs, it is highly desirable that they be nested in the bomb bay with their tail fins 45 to the horizontal. The aileron controlling contactors therefore have their neutral position rotated through 45 as indicated in Fig. 16, so that there is initially applied to the bomb an'raileron efiect which remains until the bomb has rotated 45, thus placing the rudders in and 6.

the cont'actor I00, Fig. 16, is'to open the'ground connection to relay coil I00 at the equilibrium 0 position of the directional gyro. Contactor I09 opens the ground connection to relay I00 at an ex cessively large deviation of the rate gyro in one direction, and closes the ground to relay I00 at an excessively large deviation ,of the rate gyro in the other direction (i. e., when contactor I" is open). v

Fig. 16-is a detailed schematic diagram of the gyro unit, connections being made as shown.

After the bomb has been released, terminals I0 'and I5 connect to the positive terminal of-the bombs battery, as will be described later, thus supplying power to the gyro motors 99 and 94 through radio frequency choke 95 with condenser bypass to ground. Choke and condenser 90 serve as a filter to prevent commutator interference with other apparatus on the bomb. Un-

caging solenoid 91 is powered from terminal ll,

and is energized on launching the bomb, as wil be described.

In Fig. 16, terminal center contacts 99 and 99 of a. relay whose coil is shown at I00. Contacts 98 and 99 are biased to connect to springs IM and I 02 when coil I00 is not energized. When relay I00 is energized, contacts 90 and 89 connect to springs I03 and I04. Relay I00 is energized from connection I4 and controlled through contactors I05 and I09 mounted on the gyro gimbals in a manner described in the aforementioned Molnar and 'Carn-' 98 and 99 are provided to handle the aileron sole-v noid current without heating or sticking. Relay coil I00 has resistor shunt III to prevent sparking at the gyro contacts and the relay contacts have relatively high resistance shunts II! to prevent sparking on opening of theaileron solenoid circuit. Wires I6 and II from thegyro unit connect to aileron'control solenoids 94a and-34b shown in Fig. 7, the detailed operation of which has been described in connection with Figs. 5

Bomb controls Fig. 17 is a wiring diagram of the bomb and shows how the various components are interconnected. The components illustrated are those for on-oil?" radio control, but the alternative proportional control may easily be substituted with obvious minor changes in the circuits to conform with the detailed diagrams previously explained. 1

Referring to Fig. 17, the bomb is equipped with a so-called kick-off plug 5|. All connections and components located below this kick-oil plug are contained in the tail member I (Figs. 1 and 2) of the bomb. Connections above plug 5| are on the bombing plane, plug 5| being at the end of a short length of four-'wire cable which pulls the plug SI out after the bomb has moved away a few feet. The four connections 52, 53, 54.55 on the plane serve certain purposes before the bomb is released. Asthe bomb drops away, the connections to these wires are severed and thereafter the bomb operates on its own as a self-contained I4 supplies power to the 16) to uncage the gyro at release.

unit Wire 54 connects directly to the ships ground and serves as an electrical ground before release. Wire 55 connects to the customary electrical bomb release mechanism on the ship and serves to uncage the directional gyro when'the bomb release mechanism is actuated by the bombardier. An electrical impulse from the release mechanism is imparted through wire 55 to perform this function as will be described later. Wire 53 is connected through switch 55 to 4 volt ship's power supply, this connection serving to supply power to various components of the bomb previous to its release so that all parts will be in operating condition when released. Switch 55 is normally closed a short time before release.

Wire 52 connects through switch 51 to the +24 v. ships power and ser es the purpose of arming the tail flare 3 (Figs. 1 and 2). This is a safety mechanism to prevent premature operation of the flare. The four wires 52, 53, 54, 55 are severed at contacts 52', 53', 54, 55 when the kick-off plug pulls out on release of the bomb, and thereafter the springs of a kick-off switch indicated generally by numeral 58 make other connections as shown. Mechanical interconnections between contact springs are indicated by arms 59 and 60 which are made of insulating material.

Considering now the operation of various components on the bomb itself, these will be described separately. Flare 3 connects through wire BI to a thermal trip relay 52. The thermal release 63 is connected by the wire 200 to contact 52'. Movable contact 64 is grounded through wire 65. Wire GI is thus seen to be open until the bombardier closes flare arming switch 51, whereupon thermal unit 63 burns out, permitting contact 54 to connect to wire SI, grounding one side of the flare. The other connection of the flare made through wire 66 connects through current limiting resistor 61 to spring 68 of the kick-off switch. When the kick-off plug pulls out on release, spring 68 connects to spring 69 and is thereby connected via wires 'II and I2 to the 24 v. battery I contained in the bomb. The negative terminal of battery I0 is grounded on the bomb. Thus the bombardier may arm the flare previous to release, and on release the severing of the kickoff plug closes the above circuit and the battery power ignites the flare fuse. A time-delay fuse allows the bomb approximately eight secondss drop before the flare ignites.

As previously stated, aileron control to maintain roll orientation of the bomb is obtained through the use of a free or directional gyro spinning in the plane of the trajectory. An auxiliary rate-of-turn gyro maintained in the same plane provides a rate-controlling mechanism. These two gyros properly coupled cooperate to prevent excessive roll oscillation of the bomb. The gyro unit itself forms the subject matter of copending application Serial No. 543,168 by Molnar and Carnvale and is indicated generally by numeral 12. Five wires l4, 15, I8, 11 and are connected to the gyro unit whose internal circuit is shown in Fig. 16. Wire ll connects through spring 10 to contact 55' on the kick-01f plug and via wire 55 to the bomb release mechanism. An electrical impulse from the release mechanism is thus transmitted to wire 14 to the uncaglng solenoid 9'! (Fig. In order to make sure that the gyro does uncage properly, spring I9 connects with spring 8| after the kickofl' plug is pulled and' this serves to connect wire 14 through spring I9, spring 9|, and wire I2 to the bomb's battery 10 to eflectively actuate the gyro uncaging mechanism.

Wire I5 from the gyro motors (Fig. 16) is seen to connect through current limiting resistor 00 and wire BI and spring 82, thence through contact 53' and wire 53 to the bombardiers warm-up switch 55. Thus the bombardier may, before release, set the gyros irrmotion. Subsequent to release, that is, when connection 53' has been broken, power to wire 15 is supplied through wire 03 and spring 84 connecting to spring 85, thence via wire 86 and wire I2 to the battery 10 on the bomb. One may also note at this point that warm-up switch 56 leading through wire 53, contact 53 spring 02, wire BI, and rectifier 81, wire 88. wire 86, wire 12, supplies ships power to maintain the 24 v. battery on the bomb fully charged.

Wires l8 and 11 from the gyro unit connect via wires 89 and 90 to aileron control solenoids 9| and 92, shown also as 34a and 34b in Fig. '1, the detailed operation of which has been described in connection with Figs. 5, 6 and 7. Wire 18 serves as a ground for the gyro unit. Wire I01 serves as a ground return for the aileron control solenoids through springs I08 and I09 and wire IIO after the bomb is released. Thus the aileron control solenoids cannot be energized except after release from the bomb bay.

Returning to Fig. 17, it is seen that wire 15 connects to wire 89 and energizes solenoid 82, current returning toground via wire I01, spring I00, spring I09, and wire IIO. Wire 11 leads through wire 90 and clockwise solenoid coil 9| and to ground through wire I01, spring I08, spring I00, and wire I I0. Thus, it is seen that the gyro unit controls the operation of either clockwise aileron solenoid 9| 0r counterclockwise aileron solenoid 92, in accordance with the previously given explanation of Fig. 16. I

Referring again to Fig. 1'7, the radio equipment on the bomb is shown generally by numeral I30 receiving itssignals from antenna 46. Radio unit I34 comprises a receiver and the necessary rudder control relays. In the case of simple on-on! control, unit I34 comprises a receiver 41, filter L,

relay L, filter R and relay R all shown in Fig. 13,

the operation of the relays having been explained in connection with Fig. 14. Thus connection I32 goes to ground via wire I31. For operating the radio after release of the bomb and consequent removal of the kick-off plug, terminal I3I is supplied with 24 v. power through wires I82 and 08, springs 84 and 05, wires and I2. Prior to release and while the warm-up switch 56 is closed the radio receiver, is supplied by ships +24 v. power through wire 53, contact 5!. spring 02, current limiting resistor 00, wires I02 and Ill. The 24 volt side is via ground in the receiver to bomb case and via wire III, spring I00, contact 54' and wire 54 to the aircraft ground connection. Thus the radio receiver is warmed up and in operating condition prior to release of the bomb. Terminals I28, I25, and I30 are connected to the rudder actuator. The actuator itself has been described in connection with Fig. 15, and the radio 'equipmentserves by means of its relays to apply a ground to the appropriate connection desired. In theabsence of a control signal, terminal I29 is grounded and rudders arein center position Thus, for right rudder, the radio apparatus grounds terminal I30, at the same time opening the ground on centering terminal I29. Similarly, for left rudder, terminal I20 is grounded and the ground on I29 is opened. These connections are accomplished by the relay circuit already described in Figs. 14 and 15.

The rudder actuating mechanism is indicated in Fig. 1'7 by numerals I60. This mechanism is powered with 24 v. power from the bomb battery through a circuit as follows: starting from battery 10, through wire 12, wire 86, spring 85, spring 84, wire 83, wire I62, wire I63 to the rudder actuator. A ground connection is obtained 'through wire I68 and I31. The other three terminals of the actuating mechanism go to radio terminals I28, I29, I30 and the direction of rotation of the rudder actuating motor is controlled as previously explained with reference to Fig. 15. Having thus described our invention in detail and the manner in which it accomplishesits objects, it is apparent that various changes and modifications in the details may be made by those skilled in the art and we do not mean to be limited in the controls to the particular embodiments illustrated. Furthermore, our invention may be applied to a dirigible bomb of any type or size and is not limited to the demolition-type bomb herein suggested. It may furthermore be used in the bombing of elongated targets which are moving as well as stationary targets.

What we claim as our invention is:

l. A dirigible missile comprising a war head, a unitary tail structure, cruciform aerodynamic control surfaces fixedly mounted on said tail structure, electrically insulated struts extending between said control surfaces and serving as a radio antenna, aerodynamic steering surfaces operably mounted onthe trailing edge of said control surfaces, meanscontained in said tail structure operating one pair of diametrically opposite steering surfaces as rudders which place the missileinto an attitude of yaw so that the associated control surfaces may produce forces deflecting the path of the missile, means contained in said tail structure receiving and transducing a' radio signal, means contained in said tail structure controlling the rudder deflection proportional to the deflection of the control stick In the controlling aircraft, means contained in said tail structure operating the other pair of diametrically opposite steering surfaces as ailerons tending to axially rotate the missile, and gyroscopic means in said tail structure controlling said aileron operating means so that resulting aileron action maintains the missiles rotational orientation such that the rudders li'e substantially in a vertical plane.

2. A dirigible missile comprising a war head, a unitary tail structure, cruciform aerodynamic control surfaces fixedly mounted on said tail structure, electrically insulated struts extending between said control surfaces and serving as a radio antenna, aerodynamic steering surfaces operably mounted on the trailing edge of said control surfaces, means contained in said tail structure operating one pair of diametrically opposite steering surfaces as rudders which place the missile into an attitude of yaw so that the associated control surfaces may produce forces deflecting the path of the missile, means contained in said tail structure receiving and transducing a radio signal, means contained in said tail structure controlling the rudder operating means insuch manner that the rudders are urged into their extreme steering positions in response to the frequency of modulation of the received such that the rudders radio signal and are urged into neutral position upon the absence of modulation of the received radio signal, means contained in said tail structure operating the other pair of diametrically opposite steering surfaces as ailerons tending to axially rotate the missile, and gyroscopic means in said tail structure controlling said aileron operating means so that resulting aileron action maintains the missiles rotational orientation lie substantially in a vertical plane.

RALPH D; WYCKOFF. JULIUS P. MOLNAR. LOYAL D. PALMER. GUY C. BLEWETT.

REFERENCES CITED The following references are of record in the fi1e of this patent:

UNITED STATES PATENTS Number Name Date 708,411 Semple Sept. 2, 1902 1,537,713 Sperry May 12, 1925 1,890,175 Brandt Dec. 6, 1932 2,165,800 Koch July 11, 1939 2,425,558 Ohlendorf Aug. 12, 1947

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