The brass inertia pellet (11) containing an igniferous detonator (9) is closed by the screwed plug (11A). In the unarmed position the inertia pellet is prevented from moving forward on to the steel needle (5) by the five centrifugal segments (6) which intervene between the base of the screwed plug (2) and the top of the inertia pellet. The seg-ments are pivoted on the brass pin (6A) and are prevented from turning outwards by the brass sleeve (7). The sleeve is held in position by the two spring fingers (8A) on the col-lar (8).

On acceleration, the sleeve (7) sets back and is held in this position by the engagement of the spring fingers (8A) with the step (7A) in the sleeve (7). The segments are now free to open out under the action of centrifugal force. There is no creep spring. The inertia pellet, therefore, carries the detonator lightly against the needle during flight. The detonator is closed by a copper disc which is as thick (0.004 in.) as that used in the 3 grain "A" detonator, of the British base fuze.

On impact the flash from the igniferous detonator passes through the flash hole (3A) and enters the delay unit (3). After passing along transversely drilled channels, forming a labyrinth, it leaves via hole (3B) and enters the pressed gunpowder pellet (4A). The flash from the delay passes through two flash holes (4B) and is picked up by a small amount of loose grain gunpowder (14) which communicates the flash to the pressed gunpowder pel-let in the magazine (13).

The delay is obtained by the burning of the pressed gunpowder (4A) and probably to a certain extent by the labyrinth in the delay unit (3).

The general arrangement of the inertia pellet, arming mechanism, and delay unit is similar to that to other German base fuzes, previously examined, althrough in these fuzes the hole corresponding to (3B) had been drilled or blown through, thus bye-passing the laby-rinth in the delay unit (3).

The most likely cause of blind with this type of fuze would be the failure of one or more of the centrifugal segments to swing completely out of their safe position. Even a slight overlap of one segement would prevent the inertia pellet from moving forward on impact.

Fig. 1