Original Item: Only One Available. This is a completely INERT example of a WWII Japanese Naval Aerial Bomb tail fuze, and is in compliance with the current BATF standards on inert ordnance. Not Available For Export.

This fuse was sent home in 1945 by United States Navy Reservist D. W. Christenson, a Mineman 2nd Class who was apart of Bomb and Mine Disposal Team #3. Scanned color copies of the original paperwork are included with the purchase.
 
The Japanese Navy classified bombs as land attack, ordinary, and special bombs. Land attack bombs were relatively cheaply manufactured bombs designed for use against ground targets while ordinary bombs were more carefully manufactured and were intended for use against shipping. However, the distinction was not sharp and both would have been described by the Americans as either general purpose or armor piercing bombs. Special bombs included antisubmarine bombs, air-to-air bombs, cluster bombs, certain armor-piercing bombs, and chemical bombs.
 
The Japanese Navy designated bomb designs by type (year introduced to service, with 1939 being Year 99 and 1940 being Year 0), number (which the approximate bomb weigh in tens of kilograms), model (for major types) and modification (for minor changes). Thus the Type 99 Number 25 Model 1 Ordinary was a bomb brought into service in 1939 that weighted approximately 250 kg (551 lbs) and was the first antishipping bomb design adopted that year. Special  bombs used Marks in place of Models, so the Type 99 Number 80 Mark 5 was a special-purpose bomb (in this case, armor-piercing) weighing 800 kg (1760 lbs) and introduced in 1939.
 
Bomb fill was typically either Shimose (picric acid), Type 91 (trinitroanisole), or Type 98 (70% trinitroanisole, 30% hexanitrodiphenylamine). Type 91 was considered particularly insensitive.

Number 80 bombs were too heavy to be carried by dive bombers and were intended for delivery by torpedo bombers and fast attack bombers. The Number 50 bombs were too heavy for the D3A "Val" but could be carried by the D4Y "Judy".
 
This Type D-2 (A) bomb tail fuze is one of three variations (A, B & C), similar in style and function. It is a clockwork time-delay mechanism designed for aerial burst incendiary bombs. The graduated timing ring turns to select the time delay (seconds) and is adjusted before the bomb is mounted to the plane. A set screw locks the ring in place. Since the time delay is not adjustable after take-off, a pre-determined bomb run altitude is required so the bomb detonates at the correct elevation, usually about 100 to 175 feet above the target. After the bomb is dropped, the wind vane is free to turn and spins up to a stop on a spring-loaded shaft which unlocks the timing mechanism. (Unlike the B-3 Series tail fuze, this wind vane remains attached.) A spring-driven clock then runs and turns a timing rotor at a predetermined rate. When the timer completes its travel, mechanisms automatically actuate the firing pin.
 
There is a centrifugal safety which arms only after the bomb is spinning at 1000rpm, (similar to anti-aricraft artillery fuzes). Angled fins on the bomb cause this rotation. This type of fuze was introduced prior to 1940.
 
Prior to World War II, there were no formally trained bomb or mine disposal personnel, but the need became apparent when in 1939, the British navy dismantled the first German magnetic mine that had washed up on the shore of Shoeburyness, England. In 1941, the U.S. Naval Mine School was established at Naval Gun Factory in Washington, D.C., and subsequently, the Bomb Disposal School was established. The first U.S. casualty in mine disposal was in 1942, when Ensign John M. Howard was killed when he attempted to dismantle a booby-trapped German magnetic submarine-laid moored mine. About 20 trained bomb and mine disposal personnel, to include Howard, were killed in action during WWII.
 
This wonderful example comes ready for further research and display!