Drop ammunition of the Japanese Navy in World War II

A listing of the dropped ammunition developed by the Imperial Japanese Navy for the Imperial Japanese Navy Air Force during World War II . The Imperial Japanese Army produced its own dropping ammunition for its aviation units, which differed from that of the Navy.

Differentiation of types

The majority of the drop ammunition produced were aerial bombs . According to the marine nomenclature, they were divided into three groups:

• Land bombs - bombs against ground targets on land: mostly simple, made of thin-walled steel. The nose, body and tail of the bombs were often only held together with screws or even rivets, so that an impact on armored surfaces threatened to destroy the weakly constructed bomb body without causing an explosion.
• Standard bombs - types of bombs that could be used against both land and sea targets. They ranged from simple constructions to elaborately manufactured models with bomb bodies made of hardened steel, suitable for penetrating the heavy armor of large warships.
• Special bombs - as a collective term for all other bomb types

Color coding of bombs

The bombs of the Imperial Japanese Navy and the Army were coded with a color system that made it possible to determine the type of a bomb at a glance. For this purpose, colored ribbons were applied to the gray-coated bomb body at predetermined points.

In addition to these ribbons, which are broken down in the following table, in many cases, up to the introduction of the alternative labeling scheme, there were two thin red stripes - one on each of the opposite sides of the bomb - that reached from the tip of the bomb body to its end. If the bomb was correctly installed on the aircraft, they could be seen horizontally and thus functioned as auxiliary lines for the visual inspection of the installation.

Bomb type / model	Identification scheme				Alternative labeling scheme				purpose
	Tip of the nose / noseband color	Body color	Tail fin color	Hull band color	Tip of the nose / noseband color	Body color	Tail fin color	Hull band color
country	green	Gray	green	blue	Green Brown	Gray	Gray	-	Land destinations
default	green	Gray	green	-	Green Brown	Gray	Gray	-	Ship targets
Type 1	-	-	-	-	Green yellow	Gray	yellow	-	Chemical warfare agent carriers
Type 2	blue	Gray	blue	-	Green Blue	Gray	Gray	-	Anti-submarine bomb
Model 3	silver	Gray	silver	-	Green / silver	Gray	red	-	Bomb against aircraft formations
Type 4	-	-	-	-	Green white	Gray	red	-	Rocket propelled bomb against heavily armored targets
Type 5	-	-	-	-	Green white	Gray	Gray	-	armor-piercing bomb against sea targets
Model 6	-	-	-	-	Green red	Gray	red	-	Incendiary bomb
Model 7	-	-	-	-	Green / purple	Gray	purple	-	Carrier for biological warfare agents (no naval pattern known)
Model 8	-	-	-	-	Green Brown	Gray	Gray	-	Bouncy bomb
Model 19	-	-	-	-	-	-	-	-	Bomb for fighters against aircraft formations
Model 21	-	-	-	-	Green Brown	Gray	Gray	-	small explosive bombs as submunitions
Model 22	-	-	-	-	-	-	-	-	small explosive bombs, out of date
Model 23	-	-	-	-	Green Brown	Gray	Gray	-	Bombs with time fuses
Model 24	-	-	-	-	-	-	-	-	small parachute bombs for submunition drop
Model 25	-	-	-	-	-	-	-	-	Wedge bombs, out of date
Type 26	-	-	-	-	-	-	-	-	Planning version of a time bomb pattern
Model 27	-	-	-	-	Green / silver	Grey Red	-	-	rocket propelled bomb against aircraft formations
Model 28	-	-	-	-	Green Brown	silver	red	-	light (10 kg) rocket propelled bomb
Type 31	-	-	-	-	Gray	Gray	Gray	-	Land bomb with distance fuse
dummy	-	-	-	-	Green / black	Know white	-	-	-
exercise	green	black	White	-	Green / black	Know white	-	-	-
education	-	-	-	-	black	black	black	black	-
smoke	-	-	-	-	Green / black	Gray	Gray	-	-

Bomb types

Designations

The Japanese Navy marked their bombs with the following identifiers:

• Type in combination with the year the bomb was developed according to the Japanese era. For example, the year Kōki results in 2597 or 1937 according to the Gregorian calendar , the designation type 97.
• Number (No.) in combination with the rounded weight of the bomb in its weight class, divided by 10. This is how an 805 kg bomb becomes a No. 80 bomb.
• The model is appended to the identifier if there have been major changes in the construction of a bomb.
• Modification (Mod.) Is appended to the identifier if there have been small changes in the construction of a bomb.
• Type (BM), analogous to the English “Mark”, is attached to the identifier if it is a model for a special purpose, for example fighting submarines, aircraft formations or particularly well-protected targets.

Explosives

The types of explosives used for the main charge of the bombs were limited to "Schimose" ( picric acid ), type 91 explosive ( trinitroanisole ) or type 98 explosive, a mixture of 70% trinitroanisole and 30% HND.

Suspensions

The bombs up to weight class No. 25 (about 250 kg) had a U-shaped suspension above their center of gravity, with which they were attached to corresponding hooks on aircraft. This suspension could carry weights of up to 630 kg. In the case of heavier bombs, a tether was placed around the bomb body and attached to two grippers. In addition, there were handles on the holding devices of the aircraft to prevent the mounted bombs or torpedoes from rolling.

Land and standard bombs

Sectional drawings of various bomb types.

The following table lists Japanese land and standard types of bombs used in World War II. If an expert assessment was available about the exact type of use of a bomb, it is noted in addition to the country or standard identifier.

designation	Type / Art	Weight, total	Load weight	Type of cargo	length	diameter	possible detonators	introduced from remarks
No. 3 model 2	default	30 kg	14.1 kg	Picric acid	838 mm	191 mm	A-1 (a), A-3 (a)	drop-shaped out of date at the beginning of the war
No. 6th	country	63.5 kg	-	Picric acid	-	-	Type 2 model 2 mod 0 or mod 1	obsolete with Type 98 explosives as No. 6 called Mod. 1
No. 6 model 2	default	60 kg	28.2 kg	Picric acid	1,080 mm	229 mm	A-1 (a), A-3 (a)	teardrop-shaped production ended between 1940 and 1941, but continued to be used
Type 3 No. 6 model 1	country	56.4 kg	23.51 kg	Type 98 Mod.1	1,025 mm	200 mm	C-2 (a)	1944 develops penetration capacity of 200 mm reinforced concrete
Type 3 No. 6 BM 23 model 1	country	62.5 kg	23.6 kg	Type 98	1,025 mm	200 mm	Type 99 model 1/2	from 1943 head ring, against airfields
Type 97 No. 6th	country	60.4 kg	24 kg	Type 98	1,025 mm	200 mm	A-3 (a), A-3 (b)	Penetration capacity: 200 mm reinforced concrete
Type 99 No. 6 model 1	default	62.8 kg	30 kg	Picric acid	1,144 mm	225 mm	A-3 (a)	from 1939 penetration capacity: 25 mm armor steel
Type 99 No. 6 BM 2	default	63.6 kg	38.6 kg	Type 98	1,067 mm	238 mm	A-3 (a)
Type 99 No. 6 BM 2 Mod. 1	Standard / anti-submarine bomb	63.6 kg	38.6 kg	Type 98	1,073 mm	240 mm	A-3 (a)
No. 25th	country	250 kg	150 kg	Type 98	1,829 mm	349 mm	A-3 (a), A-3 (b), C-2 (a), B-3 (a) C-1 (a)	In 1938 production ended at the start of the war
No. 25 model 2	default	253.2 kg	103.6 kg	Picric acid	1,816 mm	356 mm	A-3 (a), B-3 (a)	Production previously ended, but in use until the end of the war, teardrop-shaped
Type 98 No. 25th	country	242.2 kg	96.59 kg	Type 98	1,810 mm	300 mm	A-3 (a), A-3 (b), C-2 (a), B-3 (a), C-1 (a)	from 1939, D3-A , Battle of Midway
Type 1 No. 25 BM 2 model 1	Standard / anti-submarine bomb	260 kg	144 kg	Type 98	1,829 mm	349 mm	A-3 (a), B-3 (a)	from 1941, wooden fins with predetermined breaking point
Type 1 No. 25 BM 2 Model 1 Mod. 1	Standard / anti-submarine bomb	266 kg	144 kg	Type 98	1,829 mm	349 mm	A-3 (a), B-3 (a)	from 1941, like model 1 but with a baffle plate on the tip
Type 99 No. 25 model 1	default	251.1 kg	61.52 kg	Type 98	1,809 mm	304 mm	A-3 (a), A-3 (b), B-2 (a)	from 1939 penetration capacity: 50 mm armor steel
Type 3 No. 25 model 1	country	239.4 kg	96.96 kg	Type 98	1,810 mm	300 mm	A-3 (a)	from 1944 penetration capacity: 400 mm reinforced concrete
Type 3 No. 25 BM 31 model 1	country	190 kg	79.5 kg	Type 98	1,896 mm	300 mm	Exp. Type 3	July 1944 end of the test phase
Type 3 No. 25 BM 8	Standard / bouncy bomb	280 kg	103.6 kg	Type 98	1,810 mm	300 mm	A-3 (a)	from 1944 150–250 meters jumping range
No. 50 model 2	default	507 kg	220.95 kg	Picric acid or type 98	2,356 mm	450 mm	A-3 (d), B-3 (b)	from 1930, teardrop-shaped
Type 2 No. 50 model 1	Standard / armor piercing	491 kg	61.38 kg	Type 91 or Type 98	2,000 mm	396 mm	A-3 (f), B-2 (a)	from 1942, armor piercing penetration: 80 mm armor steel
No. 80	country	805 kg	381.97 kg	Picric acid	2,829 mm	450 mm	A-1 (c), B-3 (b), A-3 (d)	from 1938, B5N bomber, Battle of Midway penetrated up to 400 mm reinforced concrete
No. 80 model 1	default	807.5 kg	323 kg	Type 98	2,829 mm	450 mm	A-1 (c), A-3 (d), B-3 (b)	from 1938, penetration capacity: 70 mm armor steel
Type 3 No. 80 BM 8	Standard / bouncy bomb	850 kg	314.5 kg	Type 98	2,829 mm	450 mm	A-3 (a)	from 1944, 150-300 meters jumping range
Type 3 No. 80 BM 31 model 1	country	676.05 kg	392 kg	Type 98	3,189 mm	450 mm	Exp. Type 3	July 1944 end of the test phase
Type 99 No. 80 BM 5	Standard / armor piercing	796.8 kg	22.31 kg	Type 91	2,351 mm	409 mm	two B-2 (b)	from 1941, modified 40.9 cm shell penetration power: 150 mm armored steel B5N bombers sank the USS Arizona with this type .
Type 2 No. 80 BM 5 Mod. 1	Standard / armor piercing	811.2 kg	35.69 kg	Type 91	2,330 mm	409 mm	two B-2 (b)	from 1942, series version of the type 99 No. 80 BM 5 penetration capacity: 150 mm armor steel
Type 3 No. 150 BM 5	Standard / armor piercing	1,498.6 kg	49.45 kg	Type 91	2,740 mm	409 mm	two B-2 (b)	Developed in 1942, production started at the end of the war

A type 99 No. 80 BM 5, which was dropped by a B5N bomber during the attack on Pearl Harbor in 1941 and hit the battleship USS West Virginia , did not explode and remained on the armored deck. Both detonators have already been removed from the dud here.

Missiles and missile-supported bombs

The Japanese developed a limited number of bombs, the speed of which was artificially increased by a rocket motor , and some unguided rocket models intended for use against land, sea or air targets. Strictly speaking, they do not belong to “drop ammunition”, but were listed in the corresponding investigation reports of the US Navy after the war together with aerial bombs as “rocket bombs”. Only three of these models were actually used - the armor-piercing bomb Type 3 No. 25 BM 4 , the air-to-air missile Type 3 No. 6 BM 27 and the Yokosuka MXY-7 missile for self-sacrifice.

designation	Weight	description
Type 3 No. 25 Mod. 1 BM 4	315 kg	Armor-piercing bomb used from 1944 for use against ship targets. In order to increase the penetration performance, the speed of fall of the bomb was increased by 90 m / s by a rocket motor in its rear. The bomb was 1,884 meters long and had a forged steel nose up to 23 cm thick, which was followed by a 3.5 kg type 91 explosive charge. The penetration rate was 125-150 mm armor steel, the ignition was carried out by a delay fuse. The rocket motor was operated with 15 kg of chemical fuel, the explosive charge, with only 1.26% of the total weight, is described as too weak.
Type 5 No. 1 BM 9	13 kg	Experimental air-to-surface missile for use against surfaced submarines. She carried 1 kg of explosives and reached 230 m / s. Experiments took place in June 1944 and production began towards the end of the war, but it was no longer used. Penetration performance 25 mm armor steel.
Type 3 No. 6 BM 9	84 kg	Experimental air-to-surface missile, used against landing craft or small ships. She carried 10 kg of explosives and reached up to 230 m / s.
Type 3 No. 6 BM 27 model 1	60 kg	An unguided air-to-air missile that launched the Type 99 No. 3 BM 3 replaced in combat against air targets. It consisted of a rocket motor that carried an explosive incendiary warhead weighing almost 3 kilograms. The warhead had an adjustable time fuse that ignited the charge after a maximum of 10 seconds of flight time. The rocket reached a speed of 270 m / s. The warhead when detonated released 140 pellets of iron, each of which carried a charge of white phosphorus. The pellets were distributed in a 60 ° funnel. The weapon was developed in January 1944 and introduced in February 1945.
Type 3 No. 1 model 1 BM 28	7.65 kg	Experimental air-to-air missile with 600 g of explosives in the warhead, experiments at the end of 1944. This missile used 2 kg of fuel, reached a speed of up to 400 m / s and exploded on impact.
Ōka	2,140 kg	Air-to-ground missile designed for self-sacrifice; dropped by a bomber, the engine accelerated up to 912 km / h. A pilot steered the rocket into the target, where 515 kg of explosives exploded in a 1,200 kg warhead on impact.

Incendiary bombs

designation	total weight	length	Amount and type of fire agent	Type of release	Remarks
Type 98 No. 7 BM 6 model 1	71.9 kg	1,025 mm	4 × electron containers with thermite	Delay or surcharge	from 1945, penetration capacity: 200 mm concrete
Type 98 No. 7 BM 6 model 2	66 kg	1,073 mm	2.25 kg thermite + 9 liters of flame oil	Delay or surcharge	from 1938
Type 99 No. 3 BM 3	33.7 kg	693 mm	168 × phosphorus fire body	Decomposition fuse centrifugal force	from 1939
Type 99 No. 3 BM 3 Mod. 1	33.7 kg	693 mm	168 × phosphorus incendiary	Decomposition fuse centrifugal force	Type 99 No. 3 BM 3 with four additional wings on the body
Type 1 No. 7 BM 6 model 3	67.1 kg	1,073 mm	520 × fire bodies	Delay or surcharge	from 1941, scatter circle 80 meters
Type 1 No. 7 BM 6 Model 3 Mod. 1	72.73 kg	1,073 mm	182 × Thermit fire bodies	Delay or surcharge	from 1941, scatter circle 80 meters
Type 2 No. 25 BM 3 model 1	246 kg	1,803 mm	780 × fire bodies	Disassembly + impact fuse	from 1943, against airfields, scattering circle approx. 160 meters when ignited at 30 meters, dismantling detonator can be preset to 0–50 seconds.
Type 2 No. 25 BM 3 model 2	251.8 kg	1,809 mm	1087 × fire bodies	Impact fuse	from 1943, against airfields
Type 3 No. 6 BM 3 model 1	53.64 kg	1,809 mm	261 Phosphorus fire bodies	Dismantling fuse	from 1943, against aircraft formations

Warfare agent bombs

designation	total weight	length	Type and amount of warfare agent	Type of release	Remarks
Type 1 No. 6 BM 1	69 kg	1,016 mm	18 kg BM3 mustard gas	Impact fuse destroys the housing	from 1941, converted bomb type 97 No. 6, effective radius 10 meters
No. 6 BM 1	69 kg	1,072 mm	23 kg BM3 mustard gas	Impact fuse destroys the housing	from 1936, rebuilt type 99 No. 6, effective radius 10 meters
Type 4 No. 6 BM 1	-	-	BM3 mustard gas	Impact fuse destroys the housing	Prototype from 1944 developed as a replacement for the predecessor, plywood construction.

Cluster bombs

Sectional drawings of various types of cluster bombs.

designation	total weight	length	Number and type of submunition	Type of release	Remarks
Type 2 No. 6 Model 1 BM 21	52.5 kg	1,086 mm	40 × 1 kg shaped charge bombs	Luftkrepierer dismantles the body of the container	from 1944
Type 2 No. 6 Model 2 BM 21	52.5 kg	1,086 mm	36 × 1 kg fragmentation bombs	Luftkrepierer dismantles the body of the container	from 1944
Type 2 No. 6 model 5	56.5 kg	932 mm	5 × 7 kg fragmentation bombs	Centrifugal force hurls bombs out of containers	from June 1943

Exercise bombs

designation	total weight	length	filling	Signal device for confirming hits	Remarks
1 kg exercise bomb Mod 2	1 kg	260 mm	red or white phosphorus	Fire	-
1 kg exercise bomb Mod 3	1 kg	260 mm	red or white phosphorus	Fire	-
Practice bomb No. 3 model 1	31 kg	850 mm	Concrete / wood	yes, smoke, titanium (IV) chloride	-
Exercise bomb type 99 No. 3	33 kg	910 mm	15 panes of glass / wood	yes, smoke, titanium (IV) chloride	-

Light bombs

• Type 96, 6 kg light bomb , (no umbrella), burning time 1 min 20 s, color of the light is white / green
• Model 2 Mod. 1, 5 kg parachute flare bomb (one main parachute), burning time 1 min 30 s, color of the light is white
• Type 0 Model 1, parachute flare bomb (one main parachute)
• Type 0 Model 1 Mod. 1, parachute flare (auxiliary and main parachute)
• Type 0 model 2, parachute flare bomb
• Type 0 Model 3 Mod. 1, parachute flare bomb
• Experimental model 11, parachute fluorescent bomb (auxiliary parachute and main parachute), burning time 4 min 11 s, color of the light is white
• Type 94, light bomb with float, calcium phosphide or calcium carbide charge, the light is red
• Experimental modification 1, light bomb with float
• Type 94 Model 2, light bomb with float, calcium phosphide or calcium carbide charge, the light is red
• Type 0 Model 1, light bomb with improved float, calcium phosphide or calcium carbide charge, color of the light is red

Smoke bombs with float and marker bombs

• 2 kg smoke bomb with float
• 43 kg smoke bomb with float
• Type 0 model 1, smoke bomb with float
• Type 0 model 2, smoke bomb with float
• Cardboard naval marker bomb
• Type 3 No. 6, target marker bomb
• Type 2, 2 kg target marker bomb

Other

• 2 kg chaff bomb

Detonator

Like the bombs, the detonators were also produced in-house by the Imperial Navy.

Designations

The Japanese Navy gave their detonators names that corresponded to those of the bombs for which they were intended or for which they were originally developed. During the war, however, these names were still unknown to the Allies. So they developed their own designation system that differentiated the detonators according to the type of assembly and function. The detonators with the identification "A" and "D" are head detonators that were screwed into the tip of a bomb. The detonators with the identification “B” are floor detonators that were screwed into the rear end of a bomb.

Allied name	Japanese name	Remarks
A-1 (a)	Type 2 model 2	-
A-1 (b)	Type 90	-
A-1 (c)	Type 2 model 1	-
A-3 (a)	Type 97 BM 2	-
A-3 (b)	Type 1 model 2	-
A-3 (c)	Type 2	-
A-3 (d)	Type 97 BM 2 model 1	-
A-3 (e)	Type 3	-
A-3 (f)	Type 2 No. 50 model 1	-
A-3 (g)	-	for Yokosuka MXY-7 / "Baka" bomb
A-5 (a)	-	1 kg exercise bombs
B-2 (a)	Type 99 No. 25th	-
B-2 (b)	Type 99 No. 80 BM 5	0.2 s delay
B-3 (a)	Type 15 model 2	-
B-3 (b)	Type 15 model 1	-
B-5 (b)	-	1 kg shaped charge bombs
B – 5 (c)	-	1 kg bombs
B-6 (a)	Type 97	-
B-9 (a)	-	Ōka bomb
B-10 (a)	-	Ōka bomb
C-1 (a)	Type 99 / floor	Delay from 30 minutes to 125 hours with disarming protection
C-2 (a)	Type 99 / head	Delay of up to 125 hours with disarming protection
D-2 (a)	-	Similar to the German dismantling fuse for 8.8 cm anti-aircraft grenades with a delay of 0–50 s
D-2 (b)	-	Similar to the German dismantling fuse for 8.8 cm anti-aircraft grenades with a 5–20 s delay
D-2 (c)	-	Similar to the German dismantling fuse for 8.8 cm anti-aircraft grenades with a delay of 0–20 s
D-3 (a)	-	Disassembly detonator for parachute flares
D-4 (a)	-	Disassembling fuse for parachute flares and cluster bombs
-	Type 3	electric distance igniter

Experimental detonators and bomb control systems

Type 3 - distance fuse

A new type of detonator, in which the designers completely broke with previous developments, was the type 3 detonator. It was ready for action towards the end of the war and triggered a bomb to explode electrically as soon as a sensor at its tip registered an optical signal. A bomb should be detonated a few meters before it hits the ground in order to achieve the best possible effect.

The head of this detonator is divided into a transmitting and a receiving unit:

• The transmitter unit contained an incandescent lamp for 12 volts 50 watts, with a light intensity of 170 candle strengths  , the light of which was focused through a lens with a 2.5 cm focal length . The light beam was now passed through a rapidly rotating perforated disc , so that a pulsating beam of 900–1000 light flashes per second left the fuse tip towards the ground. There it hit and was reflected.
• The receiver unit in the adjacent part of the detonator received light through a downward-facing opening, from where it was concentrated by a lens with a focal length of 15 cm on a PL-50-V1 photocell coated with cesium . A XB-767A- argon - thyratron was followed by the photocell. It supplied the bomb's ignition device with electricity as soon as light with a pulse frequency of 900 to 1000 was received by the photocell in sufficient strength. Daylight or headlights therefore had no effect on the detonator. The actual height at which the bomb exploded depended on the type of surface that reflected the beam of light. If the reflection was strong, the bomb ignited at a greater height than if it were weak.

The type 3 detonator was used for a limited time from July 1944. It was used on two types of explosive bombs: the Type 3 No. 80 type 31 model 1 (676 kg) and type 3 No. 25 type 31 model 1 (190 kg). Both bombs also carried a conventional bottom fuse to trigger the explosion on impact if the Type 3 failed. Since the components in the bombs had to be preheated to operating temperature before use, they could only be used by larger aircraft with the appropriate devices:

• Type 1 bomber ( Mitsubishi G4M ): 4 × No. 25 or a No. 80
• Ginga ( Yokosuka P1Y ): 2 × No. 25 or a No. 80

Oya-Ko - distance fuse

The "mother" (Oya) - "daughter" (Ko) bomb, Type 5 No. 25 Model 33, was developed with the same aim as the type 3 detonator: to increase the efficiency of a bomb by detonating it a few meters before it hit the ground. Here they wanted to solve the problem mechanically and built a 20 kg ball into the tip of a 220 kg bomb, which was connected to the detonator in the carrier bomb with a 30 meter long cable. After the bomb was dropped, an aneroid barometer in the tail fin of the carrier bomb triggered several airbrakes at a height of about 1,000 meters, which suddenly reduced the falling speed of the carrier bomb , with the daughter bomb loosening from its anchoring at the tip and the mother bomb falling first to the ground. When the daughter bomb hit, a detonator at its tip sent a signal through the cable into the mother bomb, which caused it to explode while it was still in the air. In the event of failure of the distance igniter, a conventional bottom igniter was installed. The bomb was no longer used in the war, but development had already reached an advanced stage by the end of the war.

Drawing of a KEGO bomb as made by the US Navy after the war

Kego - homing bomb

"Kego" ("Young silkworm") was the name for a series of target-seeking bombs that were supposed to recognize a target ship via its heat radiation and attack independently. The test carrier "Kego-109" with a length of 5.5 meters and a weight of 800 kg was the most common version with around 60 samples produced. After being dropped, the bomb was slowed down by airbrakes, four wings and four control fins with hydraulically operated surfaces could then influence the flight path in the fall. A bolometer in the nose of the bomb searched for heat sources and controlled the bomb accordingly. The weapon never reached a level of development that would have allowed its use in war, but under optimal test conditions a hit rate of 10% was achieved on a target ship filled with burning coal and the engineers were confident that they could develop a working weapon.

Air torpedoes

The Imperial Japanese Navy produced a number of torpedoes that could be dropped from aircraft. The warhead on all models contained Type 97 explosives - a mixture of 60% TNT and 40% hexyl, which was detonated by an impact fuse until 1944. From 1944, the Type 91 models carried a detonator that triggered the explosion when a small floating body, which was towed above the nose of the torpedo, hit the hull of the target ship. So the less protected underside of the targets was hit and a greater impact was achieved.

The Type 4 torpedo, which was put into service shortly before the end of the war, was the only model to carry a shaped charge warhead, which, thanks to the Neumann effect, was intended to concentrate the destructive power of the cargo in one point and thus to be particularly effective against deeply tiered protection systems of heavy warships .

designation	total weight	length	Type and size of the blast landing	Speed torpedo	Range	Max. Launch speed of carrier aircraft	introduction
Type 91 modification 1	785.45 kg	5.28 m	Type 97 - 150 kg	42 kn	2011 m	260 kn	from 1941
Type 91 modification 2	836.36 kg	5.94 m	Type 97 - 150 kg	42 kn	2011 m	260 kn	from 1941
Type 91 modification 3	850.91 kg	5.28 m	Type 97 - 204.5 kg	42 kn	2011 m	260 kn	from 1942
Type 91 modification 3 (improved)	859.09 kg	5.28 m	Type 97 - 240.91 kg	42 kn	2011 m	300 kn	from 1943
Type 91 modification 3 (reinforced)	859.09 kg	5.28 m	Type 97 - 240.91 kg	42 kn	1500 m	350 kn	from 1944
Type 91 modification 4 (reinforced)	922.73 kg	5.28 m	Type 97 - 309.09 kg	42 kn	1500 m	350 kn	from 1944
Type 91 modification 7 (reinforced)	1054.55 kg	5.72 m	Type 97 - 420 kg	41 kn	1500 m	350 kn	from 1944
Type 4 BM 2 (reinforced)	986.36 kg	5.28 m	Type 97 - 304.45 kg	42 kn	1500 m	400 kn	from April 1945
Type 4 BM 4 (reinforced)	1106.82 kg	5.72 m	Type 97 - 418.18 kg	41 kn	1500 m	400 kn	from April 1945

See also

• German dropping ammunition from World War II

Evidence and references

Remarks

1. ↑ Explosives Type 98 Mod 1. is described in USNTMJ document O-25 on explosives production on page 8 with a ratio of 60 to 40.
2. ↑ OP 1667 shows the Type 2 No. 50 Model 1 on page 52 in a drawing as a teardrop-shaped construction, while USNTMJ, O-23 describes it on page 22 as cylindrical.
3. ↑ The incendiary bodies were short steel tubes filled with 50% barium nitrate and 50% aluminum powder.

literature

Bombs and detonators:

• USNTMJ Report O-23 "JAPANESE BOMBS", 1946
• Navy Department: BUREAU OF ORDNANCE "JAPANESE EXPLOSIVE ORDNANCE" - Vol. 1 - ORDNANCE PAMPHLET 1667. June 14, 1946

Type 3 igniter:

• USNTMJ Report O-24: DESCRIPTION AND OPERATION OF JAPANESE TYPE 3 PHOTOELECTRIC FUZE. 1946

Oya-Ko bomb:

• USNTMJ Report O-18: JAPANESE ORDNANCE FUZES. 1946

Kego bomb:

• USNTMJ Report X-02-1: JAPANESE INFRA RED DEVICES - Article 1 - CONTROL FOR GUIDED MISSILES. 1946

Torpedoes:

• USNTMJ Report O-01-2: JAPANESE TORPEDOS AND TORPEDO TUBES - Article 2 - Aircraft torpedos. 1946

Individual evidence

1. ↑ USNTMJ, O-23 p. 7.
2. ↑ OP 1667 p. 54.
3. ↑ USNTMJ, O-23 p. 7.
4. ↑ OP 1667 p. 54.
5. ↑ USNTMJ, O-23 p. 18.
6. ↑ USNTMJ, O-23 p. 9.
7. ↑ USNTMJ, O-23 p. 49.
8. ↑ USNTMJ, O-23 p. 8.
9. ↑ USNTMJ, O-23 p. 17.
10. ↑ OP 1667 p. 58.
11. ↑ OP 1667 p. 60.
12. ↑ OP 1667 p. 47.
13. ↑ OP 1667 p. 55.
14. ↑ USNTMJ, O-23 p. 20.
15. ↑ ^{a b} The Japanese Story Of The Battle Of Midway, translation, Office of Naval Intelligence, USN, 1947, OPNAV P32-1002 on history.navy.mil, viewed on April 2, 2012 ( Memento from January 27, 2012 in the Internet Archive )
16. ↑ USNTMJ, O-23 p. 12.
17. ↑ ^{a b} USNTMJ, O-23 p. 29.
18. ↑ OP 1667 p. 61.
19. ↑ USNTMJ, O-23 p. 19.
20. ↑ USNTMJ, O-23 p. 13.
21. ↑ USNTMJ, O-23 p. 54.
22. ↑ USNTMJ, O-23 p. 43.
23. ↑ USNTMJ, O-23 p. 21.
24. ↑ USNTMJ, O-23 p. 15.
25. ↑ USNTMJ, O-23 p. 23.
26. ↑ USNTMJ, O-23 p. 43.
27. ↑ OP 1667 p. 89.
28. ↑ USNTMJ, O-23 p. 55.
29. ↑ USNTMJ, O-23 p. 35.
30. ↑ USNTMJ, O-23 p. 36.
31. ↑ USNTMJ, O-23 p. 37.
32. ↑ USNTMJ, O-23 p. 34.
33. ↑ USNTMJ, O-23 p. 44.
34. ↑ USNTMJ, O-23 p. 51.
35. ↑ USNTMJ, O-23 p. 38.
36. ↑ USNTMJ, O-23 p. 39.
37. ↑ ^{a b} USNTMJ, O-23 p. 47.
38. ↑ USNTMJ, O-23 p. 10.
39. ↑ USNTMJ O-24 p. 11.
40. ↑ Navy Department: BUREAU OF ordnance "JAPANESE Explosive Ordnance" - Vol 1 - ORDNANCE 1667. PAMPHLET. S. 92, 93.