GB1265076A - - Google Patents

Abstract

1,265,076. Optical apparatus. RHEINMETALL G.m.b.H. June 13, 1969 [June 15, 1968], No. 30197/69. Heading G2J. The angle of jump, i.e. the angular difference between the set angle and the angle of departure, of a projectile leaving a barrel is determined by recording on a common film strip against a time scale the following three steps. (1) The angle of deflection of a first beam of light 3 projected initially perpendicularly on to a plane mirror 6 fixed to the barrel 2 adjacent the barrel exit with its plane perpendicular to the barrel axis, the beam 3 being reflected into the convex 1 by a mirror 7. (2) A second beam of coherent light 15 is arranged to pass in front of the barrel 2 normal to the barrel axis a distance from its exit equal to the length of a projectile, the beam having a path to the camera via mirrors 16, 17. The film records the interruption of the beam by a projectile leaving the barrel. (3) A third beam of light 8 from a laser 9 is focused on to a vertical slit 18 at the barrel exit, the beam being perpendicular to the barrel axis, and the diffraction pattern formed by the slit being recorded on the film with the aid of mirrors 11, 12 and magnifying system 20. Thus step (1) shows against timing markings the angle of deflection # of the barrel. Step (2) records the moment of emergence of the projectile and step (3) records deviation of the diffraction pattern which enable the cross velocity V t of the barrel to be evaluated. From those graphs can be calculated the actual angle of departure α and the projectile velocity V.