Mk 233 (Nose Electrical)

Bombs

Functioning

Armed condition

Fuzes used with

Arming time

Over-all length, inches

Body diameter, inches

Material

Steel

General: The fuze will function instantly upon explosion of the electric semi-cap. It is mechanically armed by means of a motor in the plane. The body is that of a Nose Me-chanical Impact Fuze AN-Mk 219, in which the vanes, cap, and rotors have been remo-ved, and a hole has been drilled in the shoulder for the accommodation of electric wiring. A rotor block has been inserted in the rotor cavity in the fuze body. The rotor block con-tains an electric semi-cap with lead-in wires and a detonator. These units are assemb-led, unarmed. 180 degrees from the booster lead-in in the fuze body.

Operation: In the unarmed position the detonator in the rotor is offset 180 degrees from the booster lead-in. To arm the fuze, the rotor is rotated 180 degrees, at which point the detonator and booster lead-in are aligned. This is accomplished by means of a motor in the airplane, exerting a pull on one end of the arming cable. This pull rotates the pulley to which the other end of the cable is secured, and thereby rotates the rotor to the armed position. There it is locked by the lock detent. Continuing force of the motor's pull on the arming cable shears the 0.035-inch copper shear wire which secures the cab-le to the pulley.

The protective shipping cap covering the connector plug is removed when the fuze is assembled to the bomb, and connection is made with the source of electrical current in the airplane. Closing the electrical circuit after the fuze is armed successively initiates the semi-cap, detonator, booster charges, and explosive charge in the bomb.

Remarks: The detonator consists of lead azide, and the booster lead-in and booster consist of tetryl.

Figure 370. Nose Electrical Firing Fuze Mk 233