Principal Markings: El.A.Z. (106)*. Ent. (106) complementary component for El.A.Z. (106).

DESCRIPTION. The El.A.Z. (106)* is essentially a switching device for three electric ig-niters within it, and is normally battery operated. Ent. (106) is a complementary compo-nent acting as an electric reservoir, which can supply sufficient current to fire the elec-tric igniters (r) and (w) of the (106)* fuze if the leads from the 30 volt battery should be damaged. Neither the (106)* nor the (106) has plungers and only the (106)* contains explosive components.

The fuze case (5) is of mild steel, and is of the type well known in the (55) fuzes. There is no charging boss, however; the top (6) of the fuze is flat and fitted with two nipples (7) and (8), through each of which two red leads pass. These nipples take the place of the charging plungers of the ordinary "condenser" fuze.

Immediately under the top of the fuze is a molding (9) of brown plastic which has two housings containing sockets (10), (11), to take the pins of two plugs (12), (13). (See fig. 151A.) One plug may be distinguished from the other when viewed from the outside of the fuze by a narrow unpainted surrounded to the nipple remote from the locating pin of the fuze; the surround of the nipple adjacent to the locating pin being painted dark grey like the rest of the fuze. No distinction can be made by the leads – all four being red. In some fuzes the nipples remote from the locating pin of the fuze is also unpainted and the nipple itself has crossed grooves (knurled), while the nipple adjacent to the pin is painted dark grey and has longitudianl groove (splinded). The threaded ring which holds the plug adjacent to the locating pin in position is stabbed in. The other ring is not so connected.

The upper molding (9) contains an electric igniter (p) in a metal tube. Under this molding is another molding (18) of brown plastic which contains three switches (1), (2), (3) and a small metal pot (19) to thermite. This thermite is ignited by the igniter (p). It is possib-le that there is a small delay pellet between the igniter and the thermite. A spring (20) tends to open switch No. 2, but in the unarmed fuze it is prevented from doing so by the presence of a small polystyrene pellet (21) (tubular for about half its length). Switch No. 1 is held open and switch No. 3 is held closed by the restraining pull of short wires at-tached to the thermite pot (19) by blobs of fusible Woods metal in the groove (22) against the springs (23) and (24) which tend to open and close them respectibely. The three switches operate by the substitution, against a spring contact, of a metal segment for an insulating one, or vice versa, in the same way as the charging plungers of an or-dinary electric impact fuze. Above the top of the molding (18) and in a recess in the mol-ding (9) is an inertiabolt switch (25) marked "150 g ± 10%", so oriented that it closes the circuit when the flying bomb falls on its nose. At the bottom of the molding (18) and to-wards the base of the fuze is a molded plastic fitting (26) in which there are two igniters (r) and (w) of the green tipped and hence, presumably, of the "sensitive" type. These igniters are in such a position that the flash from them can pass directly to a normal Ger-man gaine which screws into the threaded hole (27) in the plastic molding (28) which forms the bottom of the fuze.

Figure 151A – (106)* Electrical Impact Fuze

The flying bomb is fitted with two firing switches external to the fuze; a nose switch and a belly switch. The first is of the diaphragm type as used with fuze (55) A. It closes the circuit when the nose of the bomb hits a target, the movab-le diaphragm of the switch being forced into contact with the fixed plate by the spindle of the air-log. The second is a simple push button switch covered by a streamlined plastic molding; the push button being depressed by the molding when the flying bomb "pancakes". These two switches are electrically in parallel and closing of either of them fires the igniter (w) (see circuit-diagram). A 30-volt dry battery in the aircraft supplies the energy for firing the igniters in the fuze (106)*, connections being made via the unit (106) and a contact in the Veeder counter of the flying bomb.

Before and for a few minutes after the flying bomb has been launched the fuze is unar-med. Switch 1 is open and hence accidental closing of the inertiabolt switch cannot fire the igniter (r). Switch 3 is closed and thus short-circuits the igniter (w) and prevents it from being fired by accidental closing of the nose or belly switches. Switch 2 is closed. Several minutes after the bomb has been launched a contact in the Veeder counter is closed and applies the battery to the fuze (106)* via the unit (106) thus firing the igni-ter (p). The latter ignites the thermite, the heat from which soften the pellet (21) allow-ing switch 2 to open and throw the igniter out of circuit. (The object of this appears to be to prevent a drain on the battery due to any residual conductivity in the igniter.) The heat from the thermite also melts the blobs of fusible Woods metal in the groove (22). This allows switch 1 to close and switch 3 to open, arming the fuze. When the fuze is armed, closing of the inertia bolt switch or the nose or belly switches allows current from the battery to fire either of the igniters, thus detonating the bomb. (For wiring diagram of this fuze see fig. 151B.)

Figure 151B – (106)* Electrical Impact Fuze Wire Diagram