Patent GB-600001-A (GB)
Abstract: 600,001. Gun-fire control apparatus. VICKERS-ARMSTRONGS, Ltd., WATSON, J. P., and CLARKE, T. F., and COLE, P. W. [Representatives of INGOLDBY, M. K.]. Dec. 21, 1938, No. 37190. [Class 92 (ii)] Gun-fire control apparatus for use on aircraft in conjunction with freely-mounted shell-Bring guns, consists of an observing sight 2, Fig. 1, and a range-finder 13, a calculating apparatus 1 arranged to compute an elevating and training correction based on own height (H), speed (U), elevation (S) and training position (A) and range (R) of the target. The said correction is added to the observed elevation and training angle together with the tangent elevation and a correction based on the rate of change (Rc) of the observed elevation and observed rate of change (Rt) of sight training, to produce an output from the calculating apparatus that may be applied to the gun 21 through amplifiers as the gun training and an elevation proportional to quadrant elevation. As shown in Fig. 1, the sight 2 is moved in elevation (S) and azimuth (A) by shafts 3, 4 leading from rate-measuring apparatus, the input to the latter consisting of hand-controlled shafts 9, 10, whose position therefore give elevation and azimuth rates (Re) and (Rt). The four shafts drive further shafts 5, 6, 11 and 12 which transmit data to the computer 1, and the computer is also fed with data on shaft 14 corresponding to range (R) from a range-finder 13, on shaft 15 giving own speed (U), on shaft 17 giving muzzle velocity (MV) and shaft 18 giving a ballistic coefficient (C%). The computer solves the problem of finding the correct quadrant elevation (QE) and gun training (GT) which appear on output shafts 19, 20. Computer.-The (S) data on shaft 5 rotates a screw 22, Fig. 2, carrying a non-rotatable nut 25, and on its nut is rotatably mounted a cam' follower 24 having an arm 28 which bears on a three-dimensional cam, or camoid 31 and a second arm carrying a toothed quadrant 32. Thus, when screw 22 is rotated it translates the follower 24 which, by bearing on the camoid 31, rotates ; rotation of the follower may also be effected by rotating the cam which is geared to the (A) shaft 6 and the arrangement is such that a pinion 33 meshing with the quadrant 32 moves proportionally to F, (SA). The device including the members 22, 24, 25, 31 is called a " camoid device." Own speed (U) and own height (H) shafts 15, 16 lead to another camoid device 37 to produce a rotation of a pinion 39 proportional to f (UH), and this rotation is combined with that of pinion 33 by another camoid device 46 to rotate a pinion 47 by a quantity proportional to [f (UH x F 1  (SA)]. This quantity is combined with elevation rate shaft data (Re) from shaft 11 in a differential 48 to give a result [f (UH) + F 1  (SA) Œ Re] which is fed to a second differential 54. Shaft 5 also drives a cam 57 whose follower drives a shaft 61 as shown, the cam being so designed as to give shaft 61.a motion proportional to (K 1  cos S) and this is fed by shaft 61-to the differential 54. The output of differential 54 being proportional to [f (UH) x F 1  (SA) Œ Re Œ K 1  cos S] is fed with range (R) data from shaft 14 to a further camoid device 68 to drive a pinion 69 which receives a motion proportional to f (R) [f (UH) x F 1  (SA) Œ Re Œ K 1  cos S] or [t x f (UH) x F 1  (SA) Œ t x Re Œ t x K 1  cos S]. This pinion and also a shaft 74 driven by the (S) shaft 5 lead to a differential whose output shaft 19 gives the correct quadrant elevation which is proportional to [S Œ t x f (UH) x F 1  (SA) Œ t x Re Œ t x K 1  cos S], t being the time of flight of the projectile to the target. Further camoid devices are associated as shown with the other shafts to give the correct rotation to the training shaft 20.