ROCKETS USED IN

FUNCTIONING

ARMING CONDITION

ARMING TIME

MAX. BODY DIAMETER

OVERALL LENGTH

COLOR

MATERIAL

DESCRIPTION:

This fuze, designed for anti-aircraft purposes, is a pyrotechnic time fuze. Variable settings, from 0 to 30 seconds, are obtained by rotating the time setting ring. The time settings are indicated by numbered graduations, sub-divided to 1/4 seconds, engraved on the fuze body below the time setting ring.

The fuze consists of a brass fuze body, a brass cap, and an upper time ring and lower time setting ring.

The brass nose cap has a flat top with five perforations, the center one leading to the striker recess and the remaining four leading to the recess accommodating the plunger. In this nose cap are located the striker and the striker spring. The spring is en-closed in an aluminum alloy plunger. Supporting the striker and the plunger are two brass pawls, pivoted in a pawl housing which is screwed into the bottom of the nose cap.

Pivoted in a recess in the fuze body is a safety lever, the upper arm of which inter-venes between the striker and the percussion cap in the unarmed position. The lower end of the lever is rectangular in cross-section and fits into a spring-loaded catch. The outer end of the catch engages a recess in the time setting ring when the fuze is set on "SAFE". A turning movement is imparted to the safety lever when the outer end of the catch leaves the recess in the time setting ring, removing the upper lever arm from beneath the striker.

Beneath the percussion cap is loacted a flash channel leading to the upper time ring. A second channel leads from the lower time setting ring to the charge of gunpowder in the base of the fuze. Leading from the top of the fuze body through to the base of the fuze is a third channel provided for the escape of air pressure.

OPERATION:

When the time setting ring is moved from the "SAFE" position, the safety catch moves out of its recess and rotates the safety lever from under the striker.

During the acceleration period of the rocket, air enters the perforations in the top of the brass cap, and the pressure which builds up inside forces the plunger down over the striker. The lower edge of the plunger, bearing on the outer end of the pawls, cau-ses the inner end to lift the striker. The striker spring is thus compressed. This move-ment continues until the inner ends of the pawls are rotated clear of the striker, which is then driven into the percussion cap, initiating the delay train in the upper time ring. This in turn ignites the delay train in the lower time setting ring, which burns for the re-quired period and then initiates the gunpowder charge in the base of the fuze. The ex-plosion of the gunpowder charge initiates the gaine, which ic loacted in the adapter ring below the fuze.

REMARKS:

(1) Fuze No. 700 Mk II: This fuze is identical to the Mk I, described above, except that the striker, pawls, and spring are somewhat modified, and the safety lever as-sembly is omitted.