Mk 223 (Tail Mechanical Impact) (Obsolescent)

Bombs

Functioning

Armed condition

Fuzes used with

Arming time

Vane span, inches

Body diameter, inches

Over-all length, inches

Material

Cast-aluminum case; fuze parts are steel, aluminum alloy, and brass

General: The fuze is essentially a Mechanical Impact Fure Mk 221 with an external protective bottle-shaped casing of aluminum, a vane extension shaft, and 16 vanes in-stead of four. This casing screws onto the fuze body and is secured by two lock screws. The lower end of the vane shaft has a flattened surface and fits into a slot in the top of the fuze cap, which is attached by screws to the pinion carrier. The fuze has a delay element in the delay carrier similar to the Mk 221; and a celluloid window in the protec-tive casing permits inspection of the fuze to determine whether or not it is in the armed condition.

Operation: When the arming wire is withdrawn, the arming vanes and the vane shaft rotate. The lower end of the vane shaft engages the cap, which rotates and revolves the pinion around the inner gears, operating the reduction gearing. The alignment of the firing-pin extension, delay carrier (firing-pin carrier in AN-Mk 219), and detonator is simi-lar to that of the Nose Mechanical Impact Fuze AN-Mk 219.

Remarks: The central spindle in this fuze does not telescope, but the collar on the central spindle which supports the hammer carrier is held by a shear wire which breaks on impact as the cap, vane carrier, and striker move forward under the influence of iner-tia.

The delay element consists of a primer, a delay pellet of meal "D" black powder, and a special detonator of fulminate of mercury mixture; and the auxiliary booster lead-in, booster lead-in, and booster consist of tetryl.

The moving parts housing the firing train are held in the fuze by three locking screws.

Figure 362. Tail Fuze Mk 223