AN-Mk 228 (Tail Mechanical Impact)

Bombs

Functioning

Armed condition

Fuzes used with

Arming time

Vane span, inches

Body diameter, inches

Over-all length, inches

Material

Steel, aluminum alloy, and brass; the brass parts are tin plated and some steel parts are cadmium plated.

General: This fuze is similar in design and operation to the Tail Mechanical Impact Fuze Mk 223, and is almost identical in external appearance. It is distinguished from the Mk 223 in that it has red vanes. The AN-Mk 228 has the following distinctive internal features: It has two separate explosive trains and a delay of 0.08 second; two firing-pin extensions are fitted on the lower end of the hammer carrier. Two delay elements and two delay firing pins are housed in the delay carrier. The detonator carrier has two deto-nators, and the shaft extension nuts contain two auxiliary booster lead-ins which are aligned with two booster lead-ins in the fuze body. One firing pin is slightly longer than the other; so the two firing trains are not initiated simultaneously.

Operation: As the arming wire is pulled, the vanes rotate and turn the arming-vane shaft, rotating the cap and revolving the pinion around the inner gears. Arming of the fuze then continues as in the Nose Mechanical Impact Fuze AN-Mk 219. The AN-Mk 228 has an added detent in the delay carrier which locks when the firing train is lined up. On impact, a shear wire through the supporting collar and spindle is cut, as the firing-pin ex-tensions force the firing pins into the primers.

Remarks: The delay elements consist of a primer, a delay charge of black powder, and a special detonator of lead azide; the detonator consists of lead azide; the auxiliary booster lead-ins, booster lead-ins, and booster consist of tetryl.

Figure 364. Tail Fuze AN-M 228