Description
The Nose Fuze M149 is a detonator safe nose fuze. The fuze is designed both for instantaneous action on impact and for air-burst a short distance above the target as a result of the blast wave from the first bomb of a stick of bombs. The first bomb will detonate on impact, while its blast, if of sufficient intensity, will detonate the second bomb, etc., in the air over the target. For example, if 500 pound bombs are dropped in train at 0.05 second intervals at air speed of 200 m.p.h. (14.7- foot spacing) from 10,000 feet, the burst of the second bomb in air will be at a point approximately seven feet ahead of (horizontal separation) the first bomb and 23 feet above (vertical separation) the first bomb. Other bombs in the stick will function the same distances from the bomb which precedes them.
When installing the M149 check the vane cup to see that it is free to turn. However, do not unscrew the vane cup, as only a few turns are required to arm the fuze. In the armed condition, the fuze must of necessity be very sensitive.
The fuse is equipped with three expansion chandlers, so that, as the diaphragm snaps in. it will not lie resisted by an air cushion, which might prevent complete inward movement of the diaphragm. This fuze is detonator safe. In the unarmed position, the detonator is lined up with the safety expansion chamber. If the detonator should function prematurely, the force of detonation is dissipated in this cavity, and will not set off the lead-in and booster charges.
Functioning
No information about functioning.
Hazardous Components
No information about hazardous components.
See Also
Nothing else to see.
Source(s)
MIL-HDBK-146, Fuze Catalog (1982)
TM 9-1385-51, Ammunition (Conventional) for Explosive Ordnance Disposal (1967)
OP 1664, Volume 2 - US Explosive Ordnance (1947)
USNBD - Bombs and Fuzes, Pyrotechnics (1945)
