US3064884A

US3064884A - Gun order computer

Info

Publication number: US3064884A
Application number: US697300A
Authority: US
Inventors: George A Crowther; Lawrence S Brown; William G Hampton
Original assignee: Sperry Rand Corp
Current assignee: Sperry Corp
Priority date: 1957-11-12
Filing date: 1957-11-12
Publication date: 1962-11-20
Anticipated expiration: 1979-11-20

Description

Nov. 20, 1962 G. A. cRowTHr-:R E-rAL GUN ORDER COMPUTER Filed NOV. 12, 1957 6 SheetS-She 650,965 A (eau/THE@ .4 WE1-'N65 S BROWN M//LL/AM dAMPro/v SYM' M 1TORNEY Nov. zo, 1962 Filed NOV. l2, 1957 6 Sheets-Sheet 3 L7 5*'38 CAL. 2500 Fslv 3" 5o LAL. 2650 Fsw La "5 TRUE vALUE-DETERMlNED FROM I 4 BALLlsTnc TABLES MEcHANnzED VALUE l 3 III ATf|h= f (Tf5)+.o443 Tfs- .1368

f"(rf5)= .ozge(ffs-3) I.2 FORTf5 3 5.25

.1096(Tf5 1.64) 1.10- FoR ;Tfs .5. 25

= .2|92(Tf5e.32)

FoR Tf5 8 L00' u) Y y 3.

o W g E2=zo .9o u IJJ .ao Hf E2 0 .6o ATfn .o I l I/ I I. I I I I I I l l I- V Y. JO

l l l l l I I l 0 l 2 3 4 5 6 7 8 9 l0 Il l2 I3 I4 5" TmE oF FL|G.HT sEcoNDs lNvENoRs 5y MW' ATTORNEY Nov. 20, 1962 G. A. cRowTHl-:R ETAL 3,064,884

GUN ORDER COMPUTER 6 Sheets-Shea?l 4 Filed Nov. l2, 195'? NN www RWOP Y ooe mi; m ci m mAa, A MM @em www., WM

Nov. 20, 1962 Filed Nov. l2, 1957 G. A. CROWTHER ETAL GUN ORDER COMPUTER 6 Sheets-Sheet 5 L A wRE/vcf S. 3190 rwv W//L z. MM Q. HAM/P TOM BY MHD/ ATTORNEY United States Patent O 3,064,884 GUN ORDER COMPUTER George A. Crowther, Lawrence S. Brown, and William G. Hampton, Long Island City, N.Y., assignors to Sperry Rand Corporation, Ford Instrument Company Division, Long Island City, NX., a corporation of Delaware Filed Nov. 12, 1957, Ser. No. 697,306 2 Claims. (Cl. 23S-61.5)

The present invention relates to an apparatus for converting gun orders derived from the output of the gunre control computer of a "-38 cal. gun to corresponding gun orders for a 3-50 cal. gun.

In certain types of naval glmiire controls, a gun is controlled on the moving ship from a director which maintains -its sights on the target. Various data obtained by the director and from other sources are processed through a computer to `obtain orders for the proper tiring of the gun. Two of the primary `gun orders derived from the computer are the gun elevation order angle Eg which is the ordered angle between the line of bore and its projection on the deck plane and the gun train order angle Bgr, which is the ordered angle between the vertical .plane through the ships centerline and the vertical plane through the gun bore axis, measured in the deck plane clockwise from the bow. These orders transmitted to the guns are employed to direct the guns for proper tiring.

One object of the present invention is to provide a comparatively simple apparatus for converting the order angles E'g and B'gr derived from the output of the computer of the guniire control system of a 5-38 cal. gun to the corresponding gun orders for a 3-50 cal. gun thereby avoiding the requirement of a separate complicated computer for the 3-50 cal. gun. A computer for the gun lire control system of a 5"-38 cal. gun is Computer Mark 1A Model 13. The converter embodying this invention does not affect the regular operation of the Computer Mark 1A in its solution of the 5-38 cal. gun problem.

In accordance with the present invention, increments of gun elevation and gun train respectively are computed by the converter of the present invention to be added to the 5"-38 cal. gun `orders calculated in the known manner in a compuer to produce corresponding gun orders for the 3-50 cal. guns. These increments are computed as functions of either the 350 cal. time of flight or the 5"-38 cal. time of Iilight. Straight line approximations are used extensively in the derivation of the formulas which are the basis of the mechanization. A high degree of correction is avoided to maintain simplicity, minimize the size of the converter mechanism and reduce the 'amount of components to a minimum.

GLOSSARY OF SYMBOLS S-pertaining to 3"-50 cal. gun.

5-pertaining t-o 5"-38 cal. gun.

A-inerement between 3 and 5" values.

Bgr-gun train orderthe angle between the vertical plane through the ships centerline and the vertical plane through the gun axis measured in the deck plane clockwise from the bow.

IR-rate of change of range.

)E2-predicted target elevation or ballistic position anglethe angle between the horizontal plane and the line of re to the future target position, measured upward from the horizontal plane.

Alib-director elevation angle-the angle between the deck plane and the line of sight measured in the vertical plane through the line of sight upward yfrom the deck plane.

3,064,884 Patented Nov. 20, 1962 ICC Eg-gun elevation order angle-the angle between the deck plane and the line of tire, measured in the vertical plane through the line of tire. Positive angles are measured upward from the deck plane.

AIV-change in initial velocity from normal value (value before gun has been tired) L-level angle-the angle between the deck plane and the horizontal plane measured in the vertical plane through the line of sight-positive when the portion of the deck towards the target is down.

RdB-linear elevation rate (knots)-the component of relative velocity of ship and target which is at right angles to the line of sight in the vertical plane containing the line of sight (positive when upward).

RdBs-linear Abearing ratethe horizontal component of relative velocity of ship and target which is at right angles to the vertical plane containing the line of sightpositive to the right.

Tf-time of flight-the time of flight of the projectile to the predicted or future target position.

ATfn-normal ditierence between Tf3 and TfS.

ATm-tirne of flight increment, correction for the time of ight due to diierence between the actual velocities of the 5 gun and the 3 gun.

Tf/RZ-conversion constant (sec./yd.).

Vfn-normal sight angle-the difference between normal gun elevation order angle and director elevation angle.

Vinsight angle correction due to change in initial velocity.

Vt-sight angle correct-ion (deg.) due to elevation rate RdE.

Zd-crosslevel angle-the angle between the vertical plane through the line of sight and the plane perpendicular to the deck plane through the intersection of the deck plane and the vertical plane through the line of sight.

Various other objects, features and advantages of the invention are apparent from the following description and Ifrom the accompanying drawings, in which FIG. l is a graph showing in `full lines the true values derived from the ballistic tables and in dotted lines the assumed values for mechanization of the AVm corrections to 3-5G cal. sight angle for loss of IV at different values of Tf3 for dilerent position angles E2;

FIG. 2 is a graph showing in full lines the true values derived from the ballistic tables and in dotted lines the assumed values for mechanization of the AVfn sight angle correction under normal initial velocity conditions at diierent values of Ty5 `for dilerent position angles E2;

FIG. 3 is a graph showing in full lines the true values derived from the ballistic tables and in dotted lines the assumed values for mechanization of ATfn at dilerent values of Tf5 for different position angles E2;

FIG. 4 is a graph showing in full lines the true values derived from the ballistic tables and in dotted lines the assumed values y:for mechanization of ATm corrections to T f for FSIV loss at different values of Tf for diierent position angles E2;

FIG, 5 is a graph showing in full lines the true values derived from the Aballistic tables and in dotted lines the assumed values for mechanization of Tf3/R2 for position tangle E2 of 45 at dierent values of Tf3; and

FIG. 6 is a diagram of a mechanism for obtaining the elevation order angle E'g and the gun train order angle Bgr.

Derivation of Formulas The difference between the 5 elevation order angle EgS and the 3" elevation order tangle -Eg3, which is also the difference between the 5" sight angle Vs5 and the 3" sight angle VS3, designated as AEg is composed of the difference AVm in superelevation or sight angle correction due to either the 3 or 5" initial velocity not being normal, the difference AVfn in superelevation or sight angle correction under normal initial velocity conditions and the dierence AVt in superelevation or sight angle correction for the elevation rate of target motion during the interval of ATf/RZ. The basic equation to be mechanized designating this relationship is as follows:

The normal initial projectile velocity is the velocity of a projectile of a gun fired for the iirst time and this velocity designated as f.s. (feet/sec.) is determined from the usual available ballistic tables for the gun. These tables indicate that the normal initial velocity of a 5-.38 cal. gun is 2.500 f.s. and of a 3.50 cal. gun is 2650 f.s. As the gun is fired, it loses initial velocity.

AVm is the difference in correction due to either the 3" or 5" initial velocity being other than normal and is shown in the graph of FIG. 1. The differences in correction to sight angle between the 3" ballistics and the 5" ballistics are so slight that they may be considered equal. As shown in the graph of FIG. 1 and as determined empirically therefrom.

Substituting in Equation 2 for AIVS and AIVS their respective equals, l-(2600-IV5) and l00-(2750-1I/3), there is obtained AVm=.00041Tf3 cos (E24-L) [100-(2600IV5) \(100l-2750-IV3)] AVm=.00041Tf3 cos (E24-L) [(2750-IV3) (2600-11/5 The true values of AVfn determined from tbe ballistic tables and the values approximated therefrom for easy mechanization are plotted in FIG. 2 as functions of AVfn cos E 2+14 in order to minimize the effect of the position angle E2.

The best mechanical solution is obtained by mechanizing the equation AVfn=f(Tfn) where AVfno is the normal correction sight angle at 0 elevation angle E2. Since this expression is a function of 5" normal time of flight, it is affected by changes in the 5" initial velocity and must be corrected. Accordingly,

AVfno=k(fTf5-}.0O03 65 TSAI V5 In the latter equation, k is not a constant but Varies. However, for the purposes of 5" correction, an average value of .175 is chosen and for AIVS is substituted its equal 100-(2600-11/5). Then AVfno=k(fTf)5+.O0639Tf5-.0000639Tf5 (Z600-ZVS) (4) In instrumentation, the product of Tf5 and IVS must be tion. Since the product of Tf3 and IVS is employed in connection with other phases of instrumentation herein, aS will be described, for the term .0000639Tf5(2600-IV5) in Equation 4, there is substituted .0000639Tf3 (Z600-1F75 to avoid the necessity of an additional amplifying step. The diierence between the values of the two terms is insignificant.

The best average solution for AVfn is obtained by subtracting a constant from AVfno AVfn: (AVfno-.24) cos (E2-I-L) AVfn: [f (TfS -l-.00639Tf5 .0000639Tf3 (Z600-ZVS) .24] cos (EZ-l-L) Referring to FIG. 2, it should be noted that the mean average represented by the graph A actually mechanized by the instrumentation of the present invention is offset by the constant vertical increment .Z4-.14. This graph A is the mean `average of the two graphs for E2=O and E2=70.

The values of 3'(Tf5 in Equation 5 for different values of Tf5 are indicated in FIG. 2 as determined empirically from the graph therein.

The only other correction to sight angle is AVt, the correction for the elevation rate of target motion during the interval of ATf/RZ.

AVt=lcRdE -l2f radians RdE is measured in knots ATf q 1s measured 1n ee/yards k=.563 yd./sec./knot of target speed 57.2958/radian k=32.26

en AVIS-32.26RdEX R2 (6) To determine the quantity ATi/R2 in Equation 6, the true and mechanized values of T f/R2 are plotted against the 3" time of iight in lFIG. 5. Since there is no appreciable change in Tf/RZ for various position angles E2 and being average, the values are plotted only for 45 position angle. Since the predicted values of the 5 inch gun computer are based on the 5"Tf/R2, it is necessary to correct only for the difference between the 3"Tf/R2 and the 5Tf/R2. 'I'his increment of Tf/RZ is equal to ATf/R2=.001110+.oooo6s5rf3 +.ooo0ooe(275o-IV3 (6a) Both the quantity Tfs Rz i and the quantity rfa have the constant .001110 as a common reference. The constant .001110, therefore, may be eliminated from equation 6a in mechanizing said equation, assuming that the input has had this constant eliminated.

In

Equations

3 and 5, the term Tf3 is involved and, therefore, it is necessary to determine the value of this amplified before being utilized for further instrumenta- 75 term for mechanization.

5 It is known that Tf3= TS +A'Tfn-l-ATm-i-.001126dRUf3 TfS) (7) (Ignoring corrections for wind, air temperature and air density) ATfn is the difference between the normal 3" time of ight and the normal 5 time of ight and is plotted on the graph of FIG. 3 as a function of the 5" time of flight. From the ballistic tables, the two true value curves for E2=0 and E2=70 indicated in full lines are plotted, and from these two curves, the true value curve representing the mean value of ATfn found to approximate that for au E2=30 is plotted in full lines. From the latter true value curve, the mechanism curve B made up of straight lines is approximated therefrom and this is used to determine the approximate empirical formula used as a basis of instrumentation. Hence:

ATm is the correction for the time of ight due to difference between the actual initial velocities of the 5" gun and the 3 gun. The LV. corrections have been plotted in FIG. 4 together with the mechanism values for both the 5" and 3 gun. The 5" LV. correction is not coincident with the theoretical value as shown by the curve C, and mechanization for ATm is, therefore, preferably along said curve, as indicated by the curve D.

Hence, as determined empirically from the graph of FIG. 4

ATm=.000365Tf5AI V5 -.000525T f3AI V3 Since TIS usually is very nearly equal to TB, then ATm=.000365Tf3Al V5 -.000=525T J3Al V3 where AIV is considered positive for increasing IV. Substituting Tf?) for Tf5 will cause a maximum error of .07 second.

`Correction for the change in range during the time of Hight is expressed in Equation 7 as .001126dR(Tf3-Tf5), since the 5" time of flight is predicted on the 5" advance range R2. This leaves only the difference between the 3 and the 5" time of i'lig tto be corrected. The constant .001126 is the average Tf/R2=.002 sec./yd. 563 yd./ sec/knot of target speed. An assumption of a fixed dR rate, equal to approximately 450 knots, further simplies the mechanization, so that Equation 7 may be re- Referring the I.V. scale to 2600 f s. for IVS and 2750 f s. for IV3, for convenience in mechanization as indicated above in connection with other phases of the mechanization, Equation 11 may be rewritten by substituting for AIVS its equal (l-AIV5) when referred to 2600 f.s. and for AIV3 its equal (100-AIV3) when referred to 2750 f.s. Therefore,

AIV3 (2750-1V3) A'IV5= (2600-1V5) Rewriting Equation 11 with the substitutions indicated, there is obtained 1.0293Tf .0919 -I- .662f (Tf) 1 .0106- .000348(2750 IV3) -I- 000242 (2600 Il/'5) (12) The value of f' TfS) is indicated in FIG. 3 for different values of Tf5.

The only corrections to gun train orders B'gr are for 1) Component of target motion perpendicular to line of sight during the difference between the 3Tf and the 5"1`f.

(2) A Dzs correction in the deck plane for trunnion tilt. The resultant bearing rate due to target and ships motion is called RdBs and is transmitted from the computer of the 5 gun. This bearing rate when multiplied by ATf/RZ gives the predicted increment of gun train when multiplied by the proper conversion constants and results in the following equation No correction AVz, i.e. difference in correction to gun elevation to compensate for trunnion tilt, is made to the gun elevation order increment AE'g, since it is assumed that the correction supplied by the computer of the 5" gun to its computed gun elevation is suicient. The converter of the present invention does supply a gun train order correction, which is an approximation of the solution of the 5" gun computer, this solution being represented as follows:

Since the inputs to the converter are 5"Eg and 5Bgr, these -do contain the trunnion tilt corrections. This results in the equation ADzs=1.22 sin ZdAEg Substituting Equation 14 in Equation 13 results in ABgr=[32.26RdBSX ATf/RZ The f(Tf5) in Equation 12 is determined empirically for the different values of TfS from the graph of FIG. 3 and these values are as follows:

f"(Tf5)=.029e(Tf5-3) for Tf5 3 5.25

=.1096(Tf54.64) for Tf5 5.25 8 \=.2192(Tf5-6.32) for Tf5 8 The y(Tf5) in Equation 5 is determined empirically for the different values of Tf5 from the graph of FIG. 2 and these values are as follows:

f"(Tf5)=.027(Tf5-3) for Tf5 3 5.25

y=.100(Tf5-4.64) for Tf5 5.25 8 l=.200(Tf5-6.32) for Tf5 8 ATf/RZ for Equation 6 is as follows: ATf/R2=.001110-1-.0000665Tf3 +.0000006(27501V3) -TfS/RZ (6a) In Equation 6a the constant .001110 is eliminated, assuming that the input TfS/RZ has had this constant eliminated.

The equation for AB'gr is as follows:

FIG. 6 shows the mechanism for the instrumentation of

Equations

1, 3, 6, 12, 6a and 15 to obtain the values of E'g(3) and Blgr(3). The inputs necessary to attain these values are (1) Tf(5) 5" time of flight.

(2) Tf5/R2 (3) I.V. (5") 5l initial velocity.

(4) RdBs Bearing rate.

(5) RdB Elevation rate.

(6) EZ-l-L Sum of elevation angle E2 and level angle L.

(7) Zd Cross-level angle.

(8) E'g(5) l5" gun elevation.

(9) B'gr(5") 5" gun train order.

(10) I.V. 3" 3" Initial velocity.

Inputs 1-9 are obtained from the output of the computer for the guniire control system ofthe 5" gun. Input 10 determined from ballistic tables is set by a handcrank 10 (FIG. 6) periodically, as for example, every day, in accordance with the number of rounds of ammunition already fired from the 3" gun.

FIG. 6 shows diagrammatically the converter by which the gun elevation order Eg and the gun train order Bgr for the 5" gun are converted into the corresponding orders for the 3" gun. In this diagram of FIG. 6, the dotted lines represent mechanical motion transmissions and the full lines represent electrical connections for transmitting electrical quantities. The mechanical motion transmitters may represent shafts, and the values of the quantities transmitted thereby are represented by the number of revolutions of these shafts. The electrical connections transmit currents, the voltages of which correspond to the values of the quantities transmitted.

The system of FIG. 6 is composed of components, such as resolvers, potentiometers, adding networks and servo mechanisms, which, per se, are well known. These, therefore, are shown only schematically and referred to brieliy.

Tf3 is one of the essential quantities required` to evaluate the 3" gun orders, and is determined from Equation 12. For the solution of this Equation 12, there are required inputs Tf5, IV3 and TV5, and the determination of f"(Tf5). As indicated in the graph of FIG. 3, the values of f"'(Tf5) vary according to the values of Tf5. A potentiometer 11 with a mechanical input Tf5 derived from the output of the 5" computer is wound to incorporate therein the values of "'(Tf5) for the different values of Tf5 according to the graph of FIG. 3, so that the output of this potentiometer will be a voltage corresponding to f"(Tf5). This quantity f"(T;f5) is then transmitted to a resistor adding network 12, the output of which is -Tf3 constituting the algebraic sum of the inputs according to Equation l2. An adding network capablerof functioning according to the foregoing requirement is described in the June 1947 issue of the publication entitled Electronic Engineering on pages 178-180 thereof. A high gain linear amplifier 13 for the output of the adding network 12 provides power amplification which serves to isolate the signal source and load impedance. Since the output of the network and

amplilier combination

12 and 13 has a 180 degree phase shift from the signal input, it

is also used for the purposes of obtaining this phase shift in order to provide means for algebraic addition.

The quantity -Tf3 obtained as described, is converted into -l-Tf3 by a network 14 and amplified in the amplifier 15, for the purpose to be described.

A further input into the adding network 12 is the electrical quantity Tf5. Since this quantity is available from the computer of the 5" gun as a mechanical quantity, this quantity is converted into an electrical quantity by a potentiometer 16 for transmission to the adding network 12.

Another input into the adding network 12 is the quantity Tf3 IV3. For obtaining this quantity, the crank 10 is set periodically, as for example, each day according to the value of IV3 obtained from the ballistic tables for the number of rounds of ammunition already tired. This quantity IV3 so obtained is fed as a mechanical quantity into a potentiometer 17 having as an electrical input the quantity Tf?, obtained as described from the output of the

combination

14, 15. The electrical output Tf3 lV3 obtained thereby from the potentiometer is fed as an input into the adding network 12.

Another input into the adding network 12 is the quantity -TJB XI V5. For that purpose, the electrical quantity -Tf3 from the

unit

12, 13 is transmitted to a potentiometer 18 receiving also the mechanical input IVS, to produce the electrical output -TSXIVS which is transmitted to the adding network 12 as an input.

The input quantities -Tf3XIV5, f"(Tf5), TS, Tf3 lV3 and ,-Tf (feedback from the output of the amplifier 13), when multiplied by the appropriate coeflcients and combined with the appropriate constants in the adding network 12 in accordance with Equation 12 are algebraically added to produce the quantity -Tf3.

The quantity to be determined in the mechanization of Equation 1 is AVm-l-AVJn. One of the quantities necessary to obtain this sum of AVm and AVfn is f" (Tf5) as indicated in Equation 5. The value of 1"(Tf5) is indicated in the graph of FIG. 2 for the different values of Tf5. This quantity f"(Tf5) has an approximately constant relationship to the quantity "(Tf5) obtained from the potentiometer 11, and the electrical output hom this potentiometer may be multiplied by a constant in a multiplying network 20 to obtain the quantity J(Tf5) as shown, or if desired, another potentiometer with the windings arranged in accordance with the relationship f"(Tf5) may be provided to obtain the electrical quantity f(Tf5). This quantity f(T]5) so obtained is transmitted to an adding network 21 as an input.

Other inputs into the adding network 21 are the electrical quantity Tf5 obtained from the output of the potentiometer 16 and the quantity -Tf3 Xl V5 obtained from the output of the potentiometers 18.

The three inputs Tf5, f(Tf5) and -Tf3 lV5, com. bined with appropriate coefiicients and constants in accordance with

Equations

3 and 5 in the adding network 21 result in the electrical quantity AVfn-i-AVm cos (E24-L) which is amplied by the amplifier 22. This amplified electrical quantity is transmitted to a resolver 23 as an input in conjunction with the mechanical quantity E2+L obtained for the computer of the 5" gun. The resolver 23 produces cos (EZ-l-L) and has a potentiometer or multiplier therein to multiply this quantity by the quantity AVfn-l-AVm cos (E24-L) to obtain the electrical output AVfn-I-AVm. 'This electrical output is transmitted to an adding network 24 as an input.

The other input into the adding network 24 is the quantity AVt. To obtain this quantity AVt, it is necessary to determine the quantity ATf/RZ in accordance with Equations 6 and 6a. The quantity TS/RZ in electrical form for the purpose, is obtained from a potentiometer 26 having TfS/RZ as a mechanical input obtained from the computer of the gun. The electrical quantity TfS/RZ so obtained is transmitted as an input to an adding network 27, which also receives as inputs the quantities -Tf3 and IV3 and also the feedback ATf/RZ from the output of an amplifier 28, the electrical quantity IV3 coming from a potentiometer 29 with a mechanical input IV3 from the crank 10. The constants and coeiiicients in accordance with the Equation 6a built into the adding network 27 result in the quantity ATJ/ R2. This quantity amplified by the amplifier 28 is transmitted to a potentiometer 30.

The positive quantity ATf/RZ is converted into the corresponding negative quantity by a network 31 and amplilied by the unit 32. The negative output is transmitted to the potentiometer 30 in conjunction with the corresponding positive quantity, since the output may be either negative or positive. The mechanical input RdE from the computer of the 5" gun into the potentiometer 30 results in the electrical output AVt, which is transmitted to the adding network 24 in conjunction with the quantity AVm-l-AVfn to produce the electrical output quantity AEg in accordance with Equation l. The electrical output quantity from this adding network 24 is processed through a servo mechanism 32 to obtain th corresponding quantity in mechanical form -to be added to the 5" gun elevation order for transmission as a 3" gun elevation order. This servo mechanism 32 is of well known type and constitutes in effect an automotive drive which positions a mechanical load in accurate correspondence with an input without placing an appreciable load upon this input. The basic components of the servo mechanism 32 comprise a servo control 33, a servo amplifier 34, a servo motor 35 and an induction generator 36, all connected in a double loop circuit with the adding network 24. Essentially, the adding network 24 computes a voltage proportional to the error between a function of the input and a function of the output. This error voltage is converted to a frequency of 60 cycles by the servo control 33, amplified by the servo amplifier 34 and supplied to the servo motor 35 for its control. The servo motor 35 furnishes the mechanical output and drives the induction generator 36. From this induction generator 36, a voltage proportional to the output velocity is supplied to the servo control 33. After being modified by computing elements in the servo control 33, the modiliedvoltage is combined Iwith the error voltage to improve the operation of the servo mechamsm.

The output of the servo motor 35 is the mechanical quantity AEg and is branched olf to a potentiometer 37 to be converted into the corresponding electrical quantity for feedback into the adding network, and is also branched olf to a summing transmitter 40 to be added to the 5" gun elevation order E'gS for the production of the 3 gun elevation order EgS and for the transmission thereof to the 3 gun control.

The transmitter 40 is of the type well-known in the gunre control systems and comprises essentially of a fine differential synchro 41 and a course differential synchro 42 operated from the quantities AEg and EgS and corrected cal quantity sin Zd. These quantities required in opposite phases because the AE'g may be positive or negative and transmitted as inputs to a potentiometer 47 in conjunction with the mechanical input AE'g, result in the electrical quantity AEgXsin Zd. This latter quantity is transmitted as an input to an adding network 48.

Also transmitted to the adding network 4S is the electrical quantity RdBsXATf/RZ obtained from the output of a potentiometer 49 having as mechanical input the quantity RdBs obtained from the 5" gun computer, and the electrical inputs -ATf/RZ and -I-AT/RZ obtained in the manner described. A further electrical input into the adding network 48 is the quantity AB'grXcos (E4-L). The quantity AB'gr obtained as a mechanical feedback from the output of a servo mechanism Sil arranged in conjunction with the adding network 48 for 4the purpose described in connection with the adding network 24 and the servo mechanism 32, is transmitted as an input to a potentiometer 51 in conjunction with the positive quantity cos (E24-L) obtained from resolver 52 and the negative quantity -cos (E24-L) obtained from the resolver 53. The resulting electrical output A'BgrXcos (E24-L) which may be negative or positive is transmitted -to the adding network 48.

The inputs AEgXsin Zd, RdBsXATf/RZ and ABgr Xcos (E2-FL) into the adding network 48 combined with the appropriate parameters in accordance 'with Equation l5 result in the electrical output ABgr which is processed through the servo mechanism 50 and converted into the corresponding mechanical quantity. The adding network 48 may be arranged in similar manner to adding network 12 referred to above. This mechanical quantity ABgr added to the mechanical quantity Bgr5 from the 5" gun computer in a summing transmitter 54 similar to the surnming -transmitter I40, results in the gun train order Bgr3 for the 3 gun. This gun order Bgr3 is transmitted for the control of the 3" gun.

Also necessary for the 3" gun control is the parallax correction Ph which is the train parallax correction for a horizontal base. A synchro transmitter system with the Ph from the 5 gun computer as an input may be provided to transmit parallax correction for the horizontal distance between the director of the gunfire control system of the 5" gun and the 3 gun mount.

What is claimed is:

l. A converter for converting the gun elevation order angle Eg of the computer of the gunlire control of a "-38 cal. gun to the corresponding gun order for a 3"-50 cal. gun, comprising means for receiving signals corresponding in magnitude to the respective quantities TfS-time of projectile ight to target from 5 gun Tf5/R2-the ratio of time of projectile iiight from 5" gun to the advance range of the target IV5-initia1 projective velocity from the 5" gun RdB-elevation rate which is the component of relative velocity of the ship on which the 5" and 3" guns are disposed and the target which is at right angles to the line of sight in the vertical plane containing the line of sight Cos (E2 +L)-cosine of predicted target elevation angle E2 from the ships deck plane on which the 5" gun is mounted plus level angle L Sin Zd-sine of cross-level angle which is the angle between the vertical plane through the line of sight and the plane perpendicular to the deck plane through the intersection of the deck plane and the vertical plane through the line of sight IV3-initial velocity of 3" gun E'gS--gun elevation order angle of the 5" gun, means responsive to the input signals Tf5, IVS and IV 3 and to a signal corresponding in magnitude to the quantity f'" (TJS) for mechanizing the equation wherein T f3=time of projectile ight to target from the 3" gun for obtaining a signal corresponding to the quantity Tf3, means for employing the input signals cos (E24-L), 1V3 and IVS, the signal Tf3 and a signal corresponding in magnitude to the signal J"(Tf) to mechanize and solve the equations A is increment between gun order values for the 3" and 5" guns Vm is the sight angle correction in gun elevation order angle due to change in initial velocity from 5" gun to 3" gun Vfn is the normal sight angle which is the dierence between normal gun elevation order angle and director elevation angle and for obtaining the signal AVm-l-Afn, means responsive to input signals IV3 and TfS/RZ and the signal Tf3 for mechanizing the equation ATf/R2=.0000665Tf3-l-.0000006(2750 -lV3)-Tf5/R2 wherein T f/RZ is the ratio of the time of ight of the projectile to the projectile target position to the advance range to the predicted target position and constitutes a conversion subtractor to obtain the signal corresponding in magnitude to the quantity ATf/RZ, means responsive to the input signal RdB and the signal ATf/RZ for mechanizing the equation AVt=32.26RdEXATf/R2 wherein Vt is the sight angle correction due to elevation rate Rde to obtain the signal corresponding in magnitude to the quantity AVt, means for adding the signal AVm-l-Afn and the signal AVt in accordance with the equation RdBs-bearing rate of ship on which the 5 "-38 cal. gun

and the 3-50 cal. gun are mounted and target Sin Zd-sine of cross-level angle, means responsive to the signals RdBs, sin Zd, AT f/R2, cos (E24-L) and AEg for obtaining a signal corresponding in magnitude to the train order angle quantity AB'gr in accordance with the relationship ABgr=[32.26RdBsXATf/R2 l +1.22 sin ZdAE' g] -cos (E2+L) and means for adding the signal AB'gr to a signal B'gr corresponding in magnitude to -the train order angle for the 5 gun to produce the train order angle for the 3" gun and for transmitting the latter order angle for control of the 3" gun.

References Cited in the le of this patent UNITED STATES PATENTS 2,434,274 Lakatos Ian. 13, 1948 2,670,134 Lakatos Feb. 23, 1954 2,766,934 Sigley et al. Oct. 16, 1956