Light beam deflection means particularly for range compensation in weapons training aids

In a gunnery training aid comprising a projector and means for moving a film through the projector, a screen onto which a beam of light emanating from the projector may be projected to form a moving image serving as a target at an apparent range, and synchronizing means for stopping movement of the film through the projector when a bullet is fired from a gun at the moving image, the improvement comprising light beam deflection means in the projector for altering the angle of inclination of the beam to a selected value which compensates for the drop in trajectory of the bullet which would have occurred at the apparent range, the light beam deflection means comprising a pivotally mounted mirror positioned to reflect the beam of light, a cam movable to a position dependent upon the selected inclination, a cam follower engageable with the cam, linkage means interconnecting the cam follower and the mirror, and a stop movable under the control of the synchronizing means between an operative extended position in which the stop acts to retain the mirror in a datum position irrespective of the position of the cam corresponding to a datum inclination of the beam, and a retracted position in which the cam follower engages the cam in such a manner that the mirror occupies a pivotal position which reflects the beam of light at the selected inclination, the stop occupying the operative position during the projection of the moving image onto the screen and being moved to the retracted position on stopping movement of the film through the projector.