Patent GB-882080-A (GB)
Abstract: 882,080. Aiming devices. MATHEMA CORPORATION REG. TRUST. Jan. 24, 1958 [Aug. 24, 1957], No. 2550/58. Class 92. Relates to an aiming device of the kind described in Specification 830,053 in which observation values of the moving target are used to compute and hold constant the angle of slope - of the plane of flight of the target, this constant angle then being used in the computer to provide a semi-automatic control for the tracking, manual control being necessary in respect of one degree of freedom of movement only of a joy-stick or similar control. This arrangement merely directs the gun continuously at the target and a further computer device is necessary to derive automatically aiming off values in order that a fired projectile should hit the moving target. According to the invention the computer device which provides the semi-automatic control of the tracking also provides the necessary data for feeding to a sighting device so that the gun is directed with the appropriate aiming- off value. In one form the computer mechanism is combined with a sighting device as described in Specification 793,243. In Fig. 7, manual control of the adjustment of the weapon is initially effected by a wheel 3 and a hand-lever 75 or foot-lever 76, the wheel 3 being subsequently automatically controlled leaving the gunner to control the lever 75 and 76 only. The bearing angle #G and the elevational angle γ are set in at shafts 1, 2 respectively, and by means of the manual wheel 3, the radial flight direction mark on a disc 8 is made to coincide with the longitudinal axis of the aircraft as described in Specification 793,243. The rotation of the wheel 3 is proportional to the apparent direction of flight # and this value is transmitted by a motor 44 to the sighting device 5 via a flexible shaft 145 and to a shaft 12. On the shaft 12 are mounted curved bodies 14, 15, 16 rotated in correspondence with the flight angle 8 and axially displaced in correspondence with the elevational angle γ through bevel gears 17 driven by the shaft 1 and through spindle 18 and nut 19. The registering members 20, 21, 22 of the curved bodies 14, 15, 16 provide respectively the bearing angle #<SP>1</SP> in the flight plane, the angle of slope r of the flight plane and the bearing angle # in the horizontal plane. The registering member 21, where rotation is proportional to #, rotates via a gear wheel 40, a curved body 41 and a contact pen disc 42 which through its relative disposition with respect to a co-operating contact disc 43 so controls the motor 44 through switching over the wheel 3 from manual to automatic drive that the motor 44 turns the shaft 12 and thus the curved body 15 in such manner as to maintain the derived angle r constant, and the wheel 3 is now automatically controlled in correspondence with alteration of the flight angle #, manual control now being necessary only in respect, of the lever 75 or 76. The angle 8 fed to the sighting device 5 together with a value #<SP>1</SP>-K<SP>1</SP> obtained from the curved bodies 14, 41 enable the aiming-off angle to be determined in the sighting device so that the gun is directed to hit the target as described in Specification 793,243, the value #<SP>1</SP> being a correction angle introduced when the aircraft altitude alters. The rotation of the wheel 3 controls the laying of the gun through a curved body 71 on a shaft 13 which is rotated proportionally to the flight angle #, the body 71 being axially displaceable by means of a nut and spindle 72, bevel wheels 73, 74 and through operation of the hand lever 75 or foot pedal 76. The displacement is proportional to the angular velocity # in the flight plane since the lever 75 or 76 #<SP>1</SP> is so operated that the gunner maintains the contact point in the reflecting optical device on the moving target. The registering member 77 turns proportionally to the elevational angular velocity w γ  and feeds this over the shaft 78 for movement of the gun in elevation and the registering member 79 turns a curved body 80 so that its registering member 81 turns proportionally to the angular velocity # #  in the horizontal plane, this being fed over shaft 82 for movement of the gun in azimuth. Corrections in respect of the angle of tilt of the gun are inserted through knobs 64, 67. A modification, Fig. 8 (not shown) is described in which a telescopic sight 100 is used instead of the reflecting optical device described with reference to Fig. 7.