Vane front edge curvature radius detection instrument

The utility model relates to an aeroengine blade exterior edge curvature radius checking apparatus. An optical system of the utility model comprises an illuminating object glass unit and an observation mirror which are arranged in the same plane, symmetrical with the normal of the measured surface, and the optic axes are perpendicular with each other. A color filter of the illuminating object glass is a piece of light glass located between a light source and a sharp edge collecting mirror, which is half translucent and half opaque and the bordering line of the two portions is perpendicular with a light path plane. A parallel flat and a steering prism are arranged between the sharp edge collecting mirror and an attachment objective lens, which are perpendicular with the light path and rotate about the vertical light path, wherein the steering prism is located between the parallel flat and the attachment objective lens, and another attachment objective lens is arranged between the attachment objective lens and