Velocity of Detonation of a Tubular Charge of Explosive

Determinations of the velocity of detonation of unconfined columns of pressed tetryl pellets, made by me in these laboratories in 1941 by means of the Buxton rotating-mirror camera1, showed that the velocity was higher by several hundreds of metres per second when there was a continuous cylindrical cavity in the column. For example, whereas the velocity of detonation in a cylinder of tetryl, 7/8 in. in diameter and of density 1.44, was 6,875 m./sec., the velocity in a cylinder of the same diameter but containing an axial cavity ¼ in. in diameter was 7,780 m./sec. Later experiments confirming and extending this result were made here by Dr. W. B. Cybulski with the same camera, after he had introduced modifications which considerably improved its accuracy.