A FIBER OPTIC SENSOR FOR HIGH-VELOCITY MEASUREMENTS OF PROJECTILES DRIVEN BY HOT GASES

A fibre optic sensor system for the measurement of the velocity of pro jectiles propelled by hot gases has been developed. It was found that fibre optic techniques have significant advantages over conventional b reakwire methods in this electromagnetically noisy environment. A simp le passive fibre system produced both accurate and reliable measuremen ts of projectile velocities which, in this study, were in the range 1- 3 km s(-1). In addition, by using a number of fibres at different posi tions along the projectile path, the average velocity of the projectil e can be determined at several points, and a velocity profile for the projectile motion obtained.