M142 (M3) (Nose, All-Ways Action Type)

Bomb

Functioning

Armed condition

Fuzes used with

Arming time

Body diameter, inches

Over-all length, inches

Material

Steel head, zinc alloy die casting

General: The Nose Fuze M142 supersedes the Nose Fuze M3. The Nose Fuze M3 was used in experimental production of the M74; however, it was found that the 1 to 2 se-cond delay incorporated in this fuze was unnecessary, as the inherent delay was suffici-ent. Therefore, it was re-designed and designated the Nose Fuze M142.

The Nose Fuze M142 is an all-ways action fuze which screws into the nose of the bomb. This fuze consists essentially of a steel head and arming-pin retainer, steel striker pin and safety pin; zinc alloy die casting striker, sleeve, fuze casing and arming pin; Per-cussion Primer M26, cavities in the end of the case filled with one gram of fuze powder, and a zinc booster cup filled with three grams of propellant powder.

The M3 differed in that it had a Percussion Primer M29, built-in delay charge compo-sed of a lead spitter fuze (potassium nitrate, sulfur, and charcoal) capped at both ends by match composition (60% black powder, 40% collodion) and a cellulose nitrate booster cup filled with one gram of fuze powder.

Operation: The retaining pin is removed when the fuzed bomb are assembled in the cluster. While the bomb are in the cluster, a spring-loaded release clip holds the release pin in the body of the fuze. Upon release from the cluster, the release clip springs off, allowing the release pin to jump out under action of its spring. This action permits the safety pin to enter the cavity in the striker, and the fuze is armed. Impact forces the striker and sleeve together, causing the striker pin to pierce the Percussion Primer M26, which, in turn, initiates the cavity charges and booster charge.

Remarks: The Percussion Primer M26 is better than the M29, since it will function even on soft surface impact.

The Nose Fuze M142A1 will replace the M142 because the latter cannot be "re-safed" after the release pin is released. The release pin can be reinserted in the Nose Fuze M142A1. Nose Fuze M142 is reclassified as substitude standard.

Figure 350. All-Ways Action Nose Fuze M142