Imperial Japanese Army Ammunition - 70mm, 81mm, and 90mm Mortar Projectiles

 Japanese Explosive Ordnance: Army and Navy Ammunition

Type 11 Year 70mm High Explosive Mortar

Weight of complete round: 4.28 lbs
Weight of main charge: 15.2 oz
Weight of booster: 1.6 oz
Explosive components:
-Main charge: TNT
-Booster: Picric
-Propellant: Nitrocellulose diphenylamine flaked powder
Overall length (w/o fuze): 7.12 inches
Maximum diameter: 69.8mm

Color:
Black overall with a red band around the nose. A yellow band is painted below the bourrelet and a white band forward of the rotating band.

Fuzing:
Type 93 instantaneous short delay mortar fuze

Used in:
Type 11 year 70mm Rifle Mortar

Description:
This projectile is similar in construction and operation to the Type 89 50mm H.E. mortar shell



70mm High Explosive Anti-Aircraft Barrage Mortar

Weight of complete round: 5.19 lbs
Weight of main charge (H.E. cylinders): 12.84 grams
Explosive compenents:
-Main charge: RDX
-Booster: Lead azide
Overall length: 11.38 inches
Maximum diameter of shell: 70mm
Length of canisters: 6.5 inches
Diameter of canisters: 0.75 inches
Length of H.E. cylinders: 3.12 inches
Diameter of H.E. cylinders: 0.69 inches

Color:
Shell - black overall with a 5/8 inches red band at nose. Canisters - zinc coated (grey)
H.E. Cylinders - black overall with a 3/16 inch red band at forward end

Used in:
70mm A.A. barrage mortar

Description:
This mortar shell consists of an outer shell containing seven canisters in each of which is an H.E. cylinder and parachute. A turned steel base is welded to the outher shell and provision is made for reception of a delay train holder, a shell propellant container, and an end cover. The delay train leads to a black powder charge which ejects the canisters from the shell. The end cover is fitted over the propellant contained and is sealed against moisture and held in position by adhesive tape. A wooden plug in a pressed steel cap closes the forward end of the shell.

The canisters contain a wooden plug in the base bored to receive a delay element and a small black powder cahrge to eject the H.E. cylinder from the canister. The steel H.E. cylinders are closed at the base and threaded at the forward end to receive a plug into which is screwed a friction cap. The explosive content is in three blocks, each wrapped in a waterproof paper carton.

Parachutes are attached to the outer shell, nose cap, and each ot the seven canisters and H.E. cylinders. The length of the parachute cords varies from 19 inches (Canisters) to 66 inchers (Cylinders). The H.E. cylinder parachute lines are attached to a friction cord which passes through the friction cap. Thus, this shell, when fired, puts sixteen separate objects suspended by parachutes in the way of low-flying aircraft, seven of which will explode if hit.

Operation:
The delay train to the first ejection charge is ignited by the shell propellant charge, and the first charge in turn ignites the delay trains to the second ejection charges in each of the canisters. The parachutes attached to the nose cap, outer shell, and canisters all open when the canisters are ejected and the H.E. cylinder parachutes open when they are ejected from the canisters. A plane hitting the parachute cord of any of the H.E. cylinders would cause the friction wire to be pulled through the friction cap initiating the explosive train.



Type 97 81mm High Explosive Mortar

Weight of complete round: 7.35 lbs
Weight of main charge: 1.19 lbs
Explosive components:
-Main charge: TNT
-Booster: Picric
-Propellant:
--Nitrocellulose and graphite: 58%
--Nitroglycerine: 7.1%
--Dinitrotoluene: 25.7%
--Dophenylamine: 0.5%
--Potassium nitrate: 8.7%
Overall length (w/o fuze): 11.5 inches
Length of fin aseemble: 3.19 inches
Maximum diameter at bourrelet: 81mm
Maximum diameter of tail fins: 81mm

Color:
Black overall with a red tip. A yellow band is painted before the bourrelet

Fuzing:
Type 93 instantaneous short delay mortar fuze

Used in:
-Type 97 81mm Mortar
-Type 99 81mm Mortar

Description:
The body is of one piece streamline construction having a threaded opening in the nose to receive the fuze adapter ring. A steel booster cup screws (L.H.) into the lower end of the shaped aluminium container which receives the gaine of the fuze. The bourrelet is well machined and has four grooves cut in it.

The fin assembly screws into a female threaded (R.H.) opening in the base of the body. It consists of a male plug welded to a cylindrical steel tube. Welded to the tube are six fins shaped to receive the six silk bags containing the propellant increments. Between each set of fins are three gas escape ports for the propellant gases from the cartridge which fits inside the tube. The cartridge is held in place by a countersunk ring screwed into the end of the tube. The cartridge resembles a shotgun shell.



Type 100 81mm High Explosive Mortar

Weight of complete round: 7.52 lbs
Weight of main charge: 1.18 lbs
Explosive components:
-Main charge: TNT
-Booster: Picric
-Propellant:
--Nitrocellulose and graphite: 58%
--Nitroglycerine: 7.1%
--Dinitrotoluene: 25.7%
--Dophenylamine: 0.5%
--Potassium nitrate: 8.7%
Overall length (w/o fuze): 11.78 inches
Length of fin assembly: 3.31 inches
Maximum diameter at bourrelet: 81mm
Maximum diameter of tail fins: 81mm

Color:
Black overall with a red tip. A yellow band is painted before the bourrelet

Fuzing:
Type 100 instantaneous short delay mortar fuze

Used in:
-Type 97 81mm Mortar
-Type 99 81mm Mortar

Description:
Except for minor details, this shell is similar to the Type 97 81mm H.E. projectile. The cup to receive the fuze gaine is held in place in the booster cup by being fitted into a brass ring which screws into the fuze adapter ring above the booster cup. There is no retaining ring to hold the cartridge in the tail fin section. Instead, the cartridge is held by a friction fit.



81mm Parachute H.E. Mortar

Weight of complete round: 3.87 lbs
Weight of main charge: 4 oz
Explosive components:
-Main Charge: RDX (1 block), TNT (2 blocks)
Overall length: 21.25 inches
Length of shell (less propellant container and nose plug): 18.5 inches
Diameter of shell body: 1.5 inches
Diameter of fins: 81mm
Diameter of H.E. cylinder: 1.37 inches
Length of H.E. cylinder: 7 inches

Color:
Black overall with an unpainted wooden plug in the nose.

Used in:
Standard 81mm smoothbore mortars

Description:
This mortar shell is a black steel tube with an ogival wooden block sealing the forward end. Six fins which give the shell an 81mm diameter are spot welded along the after part of the tub. A steel disc drilled through the center for the delay lead-in is welded to the tube 1/2 inche from the base. Forward of the disk is a 5 inch wooden block through the center of which runs the 12-second black powder delay element. The forward end of the wooden block contains the ejection charge. The H.E. cylinder and parachutes are located forward of the ejection charge. The cylinder consists of a steel case, a central tube containing the 45 second self-destruction delay train, a friction igniter, and three cylindrical explosive blocks fitted around the central tube. The booster fits in the forward block. The parachute which supports the cylinder is secured to a small fixed U-bolt on the cylinder by nine short (13 inch) shrouds. A second parachute above the first is secured to the friction igniter by a line 32'4" long. This line leads through a central hole in the lower parachute. The tinned steel propellant container is 81mm in diameter and 1 inch deep. A neck on the container cover fits into the base of the mortar shell and is secured by three small screws passing through the sides of the shell and the neck of the cover.

Operation:
When the shell is fired. the flash from the black powder primer ignites the propellant and the 12 second delay train. Setback shears the small screws securing the propellant container to the shell, and when the force of the propellant is expended the container falls free. Twelve seconds after firing, the delay train ignites the ejection charge forcing the H.E. cylinder and parachutes out the forward end of the shell. The 45 second self-destroying delay train is also ignited by the ejection charge. Planes striking the 32 foot parachute cord which is attached to the igniter will cause it to explode the H.E. cylinder. After 45 seconds, the self-destroying element detonates the cylinder.



81mm Parachute H.E. Smoke Mortar

Weight of complete round: No Data
Weight of main charge: No Data
Explosive component:
-Main Charge: Tetyl
Overall length: 21.87 inches
Lenght of shell (less propellant container and nose plug): 19.1 inches
Diameter of shell body: 1.5 inches
Diameter of fins: 81mm

Color:
Unpainted galvanized iron with a yellow wooden nose and a green band around the body

Description:
This shell is similar to the H.E. round except that there is a smoke pellet in the bottom of the suspended cylinder. Above the smoke pellet are two pellets of tetryl with a black powder delay train running through the middle. As with the H.E. round, the line to the upper parachute is attached to a pull ignited and, if pulled before the self-destroying feature operated, will detonate the charge.

Operation:
The operation is similar to the H.E. round except that the expelling charge ignites the smoke flare pellet, which burns about 53 seconds and which then ignites the short delay train which burns seven seconds before the self-destroying element functions.



81mm Parachute Flare Mortar

Weight of complete round: 4.87 lbs
Weight of flare composition: 409g
Explosive components:
-Flare composition: No Data
Overall length: 22.25 inches
Length of shell (less propellant container and nose plug): 18.75 inches
Diameter of shell body: 1.75 inches
Diameter of fins: 81mm
Diameter of flare cylinder: 1.37 inches
Length of flare cylinder: 7.75 inches

Color: Unpainted galvanized steel body with a red wooden plug in the nose.

Used in:
Standard 81mm smoothbore mortars

Description:
This mortar shell resembles in construction the 81mm H.E. parachute mortar shell, the only differences being in dimensions. A thin sheet metal tube containing the flare composition is located before the ejection charge. Two parachutes are packed in an inner sleeve 5.5 inches long made in two longitudinal half sections and are attached by means of 14 inch and 15'3" cords, respectively, to an eyebolt threaded into the forward end of the metallic flare composition. The wooden nose plug is secured to the outer shell by two small nails.

Operation:
The operation of this shell is the same as the 81mm H.E. parachute mortar shell. The ejection charge ignites the flare composition as it ejects the flare cylinder from the shell.



Type 94 90mm High Explosive Mortar

Weight of complete round: 11.8 lbs
Weight of main charge: 2.35 lbs
Explosive components:
-Main charge: TNT
-Booster: Picric (presumed)
Overall length (w/o fuze): 15.83 inches
Length of fin assemble: 4.02 inches
Maximum diameter at bourrelet: 90mm
Maximum diameter at tail fins: 90mm

Color:
Black overall with a red tip and a yellow band before the bourrelet.

Fuzing:
Type 93 Instantaneous short delay mortar fuze

Used in:
-Type 94 90mm Mortar
-Type 97 90mm Mortar

Description:
This shell is similar in construction to the Type 97 81mm Mortar shell.



Type 94 90mm Semisteel H.E. Mortar

Weight of complete round: 11.5 lbs
Weight of main charge: No Data
Explosive components:
-Main charge: TNT
-Booster: No Data
-Propellant: No Data
Overall length (w/o fuze): 14.25 inches
Length of fin assembly: 4 inches
Maximum diameter at bourrelet: 90mm
Maximum diameter at fins: 90mm

Color:
Black overall with a red tip and a green band before the bourrelet

Fuzing:
Type 93 instantaneous short delay mortar fuze

Used in:
-Type 94 90mm Mortar
-Type 97 90mm Mortar

Description:
This shell is similar in design to the Type 94 90mm H.E. shell, except that it is made of low-grade or semisteel instead of high grade steel.




Type 94 90mm Incendiary Mortar

Weight of complete round: 11.6 lbs
Weight of incendiary mixture: 2.2 lbs
Weight of burster charge: 2.75 oz
Explosive components:
-Burster charge: No Data
-Propellant: No Data
Incendiary filling: Phosphorus, carbon disulphide and 40 cylindrical rubber pellets.
Overall length (w/o fuze): 15.9 inches
Length of fin assembly: 4 inches
Maximum diameter at bourrelet: 90mm
Maximum diameter at tail fins: 90mm

Color:
Black body with blue bands around the nose, a yellow band halfway between the bourrelet and tail and white band at junction of body and tail.

Fuzing:
Type 94 instantaneous short delay mortar fuze (Presumed)

Used in:
-Type 94 90mm Mortar
-Type 97 90mm Mortar

Description:
This shell is similar in design to the Type 94 90mm H.E. mortar shell with the following exceptions:
1. An enlarge booster cup threads into the nose of the projectile. It contains a well for the lower fuze body and detonator, a burster charge, and a wooden block.
2. A fuze adapter threads into the forward end of the booster cup.

Remarks:
A shell of similar construction weight and measurements contains a filling of diphenylcyanarsine (DC). The shell is painted black overall and has a red band around the nose with a blue band adjacent to it. There is a yellow band aft of the bourrelet and a red band halfway between the bourrelet and the tail. There is a white band at the junction of the shell body and tail.



Next Time: We finish up the Imperial Japanese Army's Explosive Ordnance.

I am skipping entirely over fuzes