Description
Brass except for steel arming vanes tightening pins and firing pin.
Screwed into nose of bomb and tightened by a wrench that fits over the protruding pins.
The upper fuze body houses a striker spindle that has a firing pin at its lower end and a threaded segment at the upper end that protrudes above the body. The vane assembly consisting of four black vanes attached to a brass hub screws onto this threaded portion. Just below this threaded portion, a part of the spindle is enlarged. A rubber gasket fits down over this shoulder and a threaded washer screws down in a hole in the top of the fuze body and bears on the gasket. The spindle is drilled to receive a brass shear wire 2.5 millimeters in diameter.
The lower fuze body houses a threaded plug containing the primer and below that a threaded delay carrier. The delay train runs across the diameter of the carrier and relays on the top and bottom of the carrier serve to lead the flash away from and back to the center line of the fuze. The gaine abuts against the delay carrier. The booster housed in a brass cylinder threads onto the lower fuze body.
This fuze is essentially the same as the A-8(a). The differences are increased size of the fuze and parts and a slightly different arrangement of the delay train. The delay in this fuze runs across the diameter of the carrier with relays on the top and bottom of the carrier serving to lead the flash away from, and back to the center line of the fuze.
Functioning
On release from the plane the arming vanes unscrew and fall clear, thus freeing the striker body. Upon impact the shear wire is sheared and the striker is driven into the primer. The delay element is ignited and after burning its predetermined time, the gaine is initiated.
Hazardous Components
Primer, delay, gaine, and booster. Relay incorporated in gaine.
Physical Data
Length, overall - 9.1 in (231.1 mm)
Width, overall - 3.25 in (82.6 mm)
See Also
Nose, A-8(a), Type 4 Two Second Delay
Tail, B-8(a), Type 4 Five Second Delay
Source(s)
OP 1667, Japanese Explosive Ordnance, Volume 1 (1946)
TM-E9-1984, Enemy Bombs and Fuzes, Section VII, Japanese Fuzes (1942)
