DATA:

BOMBS USED IN

TYPE

FUZE

BURSTER

CAP (ADAPTER)

FUNCTIONING

ARMED CONDITION

IGNITERS USED WITH

ARMING TIME

OVERALL LENGHT

MAXIMUM DIAMETER

GENERAL:

Thirteen igniters were developed simultaneously for use with the "fire bombs" of which four have been standardized - the M13, M14, M15, and M16. Considered on this page are the igniters which use the M157 (E9R22) anemometer arming, all-ways action fuze, namely the M15 (E3R5) and the M16 (E4R8) igniters. The M15 and M16 differ in that the M15 is designed to be attached to the outside of the bomb by means of a clamp, while the M15 has an adapter which allows the igniter to be installed in the filler cap opening in the tank. Because of this difference, the M15 is known as an External igniter, while the M16 is called an Internal adapter.

The M15 and M16 igniters consist of either a sodium (Na) or white phosphorous (WP) M15 hand greande and a C8R1 burster (DuPont C56 blasting cap and 2.5 grams of tetryl) fitted to the M157 fuze. If the bombs are to be dropped at sea, the Na grenade is used, while if the bombs are employed against land targets, the WP grenade is at-tached. WP and Na filled M15 and M16 igniters are available and are suitable for carrier use.

OPERATION:

When the bomb is released, the arming wire is pulled permitting the anemometer vanes to rotate. The rotation of the vanes threads the arming stem out of the fuze body; the fuze is armed when the stem clears the arming balls, allowing then to fall in-ward freeing the striker for movement on impact. The arming assembly threads comple-tely out of the fuze and falls away. On impact the striker pin and sleeve are forced to-gether igniting the M26 primer. Flash from the primer initiates the black powder booster and latterly the C8R1 burster, which in turn breaks the grenade case allowing the WP or Na to ignite the incendiary mixture scattered by the bursting tank.

REMARKS:

Fuzes and igniters are shipped separately and should not be assembled until imme-diately prior to use. Likewise the igniters should not be installed until use. The fuze are shipped with a retaining pin which is removed after the arming wire is attached to the short arming wire in the fuze.

Even though the igniter is released safe and the fuze does not function, impact may break open the M15 grenade scattering its white phosphorous or sodium filler. This will ignite the gasoline gel just as though the burster had scattered the filler. For this the igniter cannot be considered to be capable of being dropped "safe" with absolute assurance of non-functioning.

The M15 ingiter is designed to be clamped externally to the tank or fin assembly at any convenient point at which a suitable clamp has been provided or improvised. In cases where no clamp has been provided, the local ordnance officer must insure 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.

The supported cap is a cap specifically designed for use with an igniter.

See page 131 for jettisonable fuel tank.