Patent GB-414742-A (GB)
Abstract: 414,742. Gunnery calculators. VICKERS-ARMSTRONGS, Ltd., and WATSON, J. P., Vickers House, Broadway, Westminster. Jan. 3, 1933, No. 225. [Class 106 (i).] Apparatus for the control of anti-aircraft gun fire comprises means whereby three vector components V1, V2 and V3 of the velocity vector V of a target moving along a curved course are corrected to allow for the curvature of the course, the corrections being applied to the respective components. In one form, Figs. 2 and 3, the components V1, V2 and V3 are taken respectively along the plan of the line of sight, along a horizontal line perpendicular to this plan line, and vertically. The apparatus (1) measures the rate of change of the difference between V1, V2 and V3 and the value which V1, V, and V3 would have if the target were moving in a straight line ; (2) multiplies these rates by t/2 (t is the time of flight) to produce mean corrections and (3) adds these corrections to the original values of V1, V2 and V3, the corrected values passing to a predictor X, Fig. 2, which calculates and transmits to the gun fuze time, gun training and quadrant elevation and also determines the time of flight. Shafts 2, 4, and 6 are operated by handles 1, 3 and 5 through the intermediary of a mechanism Z for generating range, training and elevation so as to keep pointers 9, 15 and 16 following primary pointers 10, 12 and 13 driven respectively from an external ranging device 11 and an observing sight 14, a range tuning device 7 being provided, the handles 1, 3 and 5 thus determining the principal vectors V1, V2 and V3. Taking the quantities shown in the diagram Fig. 1, in which O and P represent the observer and target, in plan in the lower part and elevation in the upper part and projected on a vertical plane in the middle part the acceleration of the components are found to be dV1/dt=V2<SP>2>/Rp cos Sp, dV2/dt=V1V2/RpcosSn and dV3/dt=0 In the mechanism Y shafts 28 and 29 driven respectively from the generated range shaft 2 and the elevating gear of the observing sight operate through cams a multiplying mechanism 27, Fig. 3, to adjust the ball of a variable speed gear 26 which drives the disc of a variable speed gear 25, the ball of which is adjusted by a shaft 18 from the V2 handle 3 which shaft also through bevel gear 20 adjusts another ball carrier 21 of a duplex variable speed drive the disc 22 of which is driven from the variable speed gear 25 so as to produce in a shaft 24 the quantity V2<SP>2>/Rp cos 3p. In a corresponding manner a shaft 43 affords the quantity V1V2/Rp cos Sp These shafts operate differential gears 30, 44 connected with the handles 1, 3 so that if the target maintains a straight course no movement of those handles is necessary. Pointers 32 and 49 driven by these handles show the difference of the accelerations of the vectors V1, V2 and the corrections required are obtained by rotating handles 33, 46 to set the ball carriers of variable speed drives 34, 47 the discs of which are driven from a variable speed drive 35 operated by a uniform speed motor under control of a cam 36 driven by a shaft 37 from the predictor X according to the quantity 2/t, t being the time of flight. The handles 33, 46 are rotated so as to make the dials 38, 48 keep pace with the pointers thereon. The handle 5 after initial adjustment would remain at rest for a straight-course target since dV3/dt=0, but for a curved course must turn to keep the dial 13 following its pointer 16 and thus sets a pointer 54, the dial 57 of which is driven by a handle 55 through another time-controlled variable speed gear 56, so as to produce the required correction to the vector V3. The corrections are passed by shafts 39, 50 and 58 to differential gears 40, 51, and 59 and so into the predictor X. In a modification, the components V1, V2, V, are taken along the line of sight, at right angles to a vertical plane through the line of sight, and at right angles to the line of sight in a vertical plane through the line of sight. In this case the mechanism is modified as shown in Fig. 5 to apply in a manner similar to that described above the quantities dV1/dt=V2<SP>2>-V3<SP>2>/Rp,dV2/dt=V2(V1 cos Sp + V3 sin Sp/Rp cos Sp and dV3/dt=V1V3-V2<SP>2> tan Sp/Rp.