Fuze M154, Igniter M13 and M14, and Experimental Type E3R1, E3R2, E3R4, E4R1, E4R2, E4R3, E4R4, E4R6, and E4R7

Bombs

Type

Fuze

Burster

Cap

Functioning

Igniter used with

Armed condition

Arming time

Armed when dropped

General: Thirteen igniters were developed simultaneously for use with the "fire bombs", of which four have been standardized - namely, the Igniters M13, M14, M15, and M16. The igniters of the M13 and M14 type use the Fuze M154, a modification of the Nose Fuze M142, the greatest emphasis being placed on the M13 and M14, which will eventually supplant all other igniters using the Fuze M154.

The Igniters M13 and M14 differ in that the M13 is designed to be attached to the outside of the bomb by means of a clamp, while the M14 has an adapter which allows the igniter to be installed in the filler-cap opening in the tank. Because of this difference, the M13 is known as an external igniter, while the M14 is called an internal igniter. The Igniters M13 and M14 consist of either a sodium (Na) or a white phosphorus (W.P.) Hand Grenade M15 and a Burster C8R1 (DuPont C56 blasting cap and 2.5 grams of tetryl) fitted to an All-Ways Action Fuze M154.

If the bombs are to be dropped at sea, the Na grenade is used, while if the bombs are employed against land targets the W.P. grenade is attached. At the present time, the Na-filled Igniter M13 is restricted and the W.P.-filled M13 is to be dumped by Navy acti-vities. Both the W.P.- and the Na-filled M14 are available. Neither the M13 nor the M14 is considered safe for carrier landings.

Operation: When the bomb is released, the arming wire is pulled, permitting the spring-loaded arming pin to move upward, thus allowing the safety pin to fly inward, arm-ing the fuze. On impact, the striker pin and sleeve are forced together, igniting the Pri-mer M26. Flash from the primer initiates the black powder booster and, latterly, the Burs-ter C8R1, which, in turn, breaks the grenade case, allowing the W.P. or Na to ignite the incendiary mixture scattered by the bursting tank.

Modifications: The following are experimental igniters developed concurrently with the M13 and the M14.

The E3R1, E4R1, and E4R2 differ from the M13 and M14 respectively in that they use an Infallible Powder burster (similar to Ballistite) instead of the Burster C8R1 of the stan-dardized models. In addition, the E4R1 has an unsupported cap instead of a supported one as in the M14 and the E4R2. The unsupported cap is a standard filling cap modified for use as an igniter. The supported cap is one specifically designed for the igniter. All three use the Fuze M154; they are restricted by the Navy to landbase training use only.

The E3R2, E4R3, and E4R4 differ from the M13 and M14 respectively in that they use a Burster C8, known commercially as the DuPont C56 blasting cap, instead of the C8R1, which is similar, except for a supplementary 2.5 grams of tetryl. In addition, the E4R4 has an unsupported rather than a supported cap as in the E4R2 and the M14. All three use the Fuze M154; for the Navy, the W.P.-filled igniters using the Burster C8 are unservice-able and should be dumped; and the Na-filled ones are restricted.

The E3R4 and the E4R7 differ from the M13 and M14 respectively in that they use the Fuze E9R20 rather than the M154. The E9R20 is an anemometer-arming all-ways action fuze converted from the Nose Fuze M154. The Burster C8R1 is present in both igniters, as in the M13 and M14, and the E4R7 has a supported cap. Both Na- and W.P.-filled ig-niters are unservieable under Navy order and should be dumped.

The E4R6 is identical to the M14, except that it has an unsupported cap. It uses the Fuze M154 and has a Burster C8R1. The W.P.-filled E4R6 is to be dumped.

Remarks: The Igniter M15 is designed to be clamped externally to the tank or fin as-sembly at any convenient point at which a suitable clamp has been provided or improvi-sed. In cases where no clamp has been provided, the local ordnance officer must ensure that the igniter is rigged in accordnance with the best ordnance practice. The clamp must be installed so that the axis of the igniter is at 90° to the axis of the tank.

Figure 374. Igniters M13 and M14, and Cutaway Showing Fuze M154