Imperial Japanese Explosives - Land Mines and Grenades (Part 4)

Imperial Japanese Explosives

  

  

Type 99 Hand Grenade
 

Overall length: 3 and 1/2 inches
Maximum diameter: 1 and 5/8 inches

Total weight: 0.8 pounds
Filling: Cast picric acid
Delay: 4-5 seconds

Color and markings: Body is black with white label pasted around it.  The top of the grenade is painted red; fuze cover, red; fuze, brass. 

Description: The cast steel body has smooth surfaces.  There is a shoulder projecting 1/16 inch from each end of the body.  The inside of the body is finished with lacquer to keep the filler from reacting with the steel case.  The filler is also wrapped in heavy paper.

A light metal flash deflector is fitted in the top of the grenade.  This deflector is 3/8 inch wide and 7/8 inch in diameter.  Two 1/8 inch holes are punched in the outer periphery and match the spanner holes in the fuze body.  This positions the gas vents in the fuze 90 degrees from the holes in the flash deflector.  The flash deflector reduces the possibility of the flash from the cap burning the hand of the thrower and the possibility of the flash being seen by the enemy at night.

The fuze is similar to that used in the Type 91 and Type 97 grenades with a few improvements.  On the old type the striker may turn or spring clear of the grenade when the safety wire is pulled.  In this fuze, a screw in the fuze body projects through a slot in the striker cover and keeps the cover in place.  The slot allows the cover to move down when the striker is struck on a hard object.  Also, the striker and inertia weight are machined together and the striker protrudes so that it does not have to be threaded down to arm the grenade.  In other respects, the fuzes are identical.

Operation: The safety pin is withdrawn and the head of the fuze is truck on some hard object.  This forces the striker down into the primer igniting the delay.

Remarks: A Type 99 grenade has been encountered with a machined, waterproof, metal fuze cover.  The only difference between this variation and the standard grenade is the fact that the flash guard is externally threaded to receive the waterproof fuze cover.

  

  

Type 4 Pottery Hand Grenade

  

Height (base to top of neck): 4 inches
Diameter: 3 inches
Body (material): Terra Cotta
Thickness of case: 7/16 inch

Total weight of grenade: 16 ounces
Filling: Type 88 explosive
Delay: 4-5 seconds

Color and markings: Light brown

Description: Except for the neck at the top, the grenade is spherical, consisting of two hemispheres baked together.  The pottery body is light brown in color, lightly glazed inside and out.  The grenade is encased in a straw-coloured rubber sack which serves as waterproofing and permits the thrower to take a better grip.

The ignition system consists of a match composition, a 4 or 5 second delay element, a lead azide initiator, and a tetryl booster.  All but the match composition are encased in a rubber tub which is lacquered into the neck of the grenade.  The upper portion of the delay element is surrounded by a wooden collar, the top of which is covered with the match composition.

A wooden scratch block is seated on top of the neck of the grenade.  It is held in place by a small rubber sack which snaps around the neck of the grenade.  This sack serves a second purpose in waterproofing the ignition system.

A cloth band tied around the neck is probably used for carrying.

Operation: The small rubber sack is removed from the top and the scratch block is struck on the protruding match composition, igniting the delay element.  The grenade is thrown and explodes after a 4 or 5 second delay.

Remarks: This grenade appears to be made of the same type pottery as the Type 3 pottery land mine, and like the land mine, uses Type 88 explosive.  For these reasons it may be assumed to be a Navy weapon.

The color of the grenade may vary from white to dark brown, and the exterior may be glazed or unglazed.

Type 23 Hand Grenade

Overall length: 3 and 3/4 inches
Maximum diameter: 2 inches

Total weight of grenade: 1 pound
Filling: Granular TNT
Weight of filling: 39.5 grams
Delay: 5 and 1/2 seconds

Color and markings: Black

Description: The body, unlike the Type 91 or Type 97, has no longitudinal serrations, but does have five transverse depressions.  On one side, fitted top and bottom, are two rings which could be used for carrying or for anchoring.  The lead cover is screwed on to the top of the grenade and is grooved to provide a grip for easy removal.  The thumb cover release holds the cover on and must be depressed before the cover can be removed.

When this is depressed, the cover can be unscrewed in one and one-half turns, thus exposing the firing string which is attached to a friction igniter.

Operation: The thumb cover release must be depressed, and then the cover must be removed.  When the firing string is pulled, it draws a sanded string through a match composition.  The ignition of the match composition will ignite the black powder delay train.

Type 98 Stick Grenade
  

Overall length: 7 and 3/4 inches
Maximum diameter: 1 and 5/16 inches

Total Weight: 1 pound, 3 ounces
Filling: Cast picric acid
Weight of filling: 3 ounces
Delay: 4-5 seconds

Color: Black body; Unpainted handle

Description: The body is cylindrical in shape and is made of cast steel 1/4-inch thick.  The handle is turned from soft wood and slips into the steel body where it is held by three screws.  This joint is sealed with a coating of tar.  The screw cap at the pull end of the handle is of light, tin-plated steel.

The fuze consists of a friction ignition composition with a sanded string running through it.  This string extends up the hollow handle and is connected to a pull ring which is exposed by removing the screw cap at the top of the handle.

Operation: The screw cap is removed from the top of the handle.  The ring inside the handle is then pulled.  This draws the sanded string through the ignition composition igniting the 4 or 5 second delay.  The delay train detonates a cap which detonates the main charge.

This grenade has more fragmentation effect than the German high explosive stick grenade.

Type 3 Conical Antitank Hand Grenade

 
Small Grenade
Length of grenade: 5 and 7/8 inches
Length of tail: 14 inches
Diameter at base: 4 inches
Length of fuze: 1 and 7/8 inches
Length of cone: 2 and 3/8 inches
Diameter of cone: 2 inches
Cone angle, apex: 38 degrees
Total weight: 0.84 kg
Thickness of cone: 3 mm
Material of cone: Aluminum

Large Grenade
Length of grenade: 6 and 3/4 inches
Length of tail: 14 inches
Diameter at base: 4 and 3/8 inches
Length of fuze: 1 and 7/8 inches
Length of cone: 3 and 3/4 inches
Diameter of cone: 2 and 3/8 inches
Cone angle, apex: 30 degrees
Total weight: 1.25 kg
Thickness of cone: 3 mm
Material of cone: Steel
  

Description:  This grenade is manufactured in two sizes.  The basic principles of construction are the same in both sizes, but variations occur in weights, measurements and the explosive charge.  The grenade consists of a cone-shaped explosive charge, a metal cone, and a wooden base all contained in a silk bag.  A fuze is inserted and a tail attached to the apex of the charge.

The explosive charge is cast in the form of a truncated cone.  A metal cone is inserted in the base and in the upper end is a well which receives the gaine of the fuze.  Surrounding the gaine is a cast ring pellet.  In the large size grenade the explosive is Type 94, and in the small size grenade it is Pentolite (50/50 TNT and PETN).  A thin layer of waxed paper surrounds the charge.

At the bottom of the explosive charge is a wooden base which is flat on the top and rounded on the bottom.  The hole in the base has a slightly smaller diameter than the hole in the cone.

Covering the charge and base is a silk bag either white or olive drab in color.  When the grenade is assembled, a drawstring closes the bottom.  A metal ring is inserted over the top of the bag.  Inside the top of the explosive charge is fitted an adapter ring which is threaded to receive the fuze.  Four screws hold the parts together.

Tied around the top of the grenade is a tail made of hemp to provide stability in flight and to make the grenade strike the tank base first.  The fuze is constructed in two parts which are threaded together.  The lower body has external threads for screwing into the adapter ring and internal threads for receiving the gaine.  The striker is held in position by a safety pin and creep spring.  The under side of the upper body and the top of the striker are curved so that if the grenade strikes at a slight angle the striker will be cammed down.
  

Operation: Before the grenade is thrown the safety pin is pulled out.  On impact the firing pine overcomes the spring and moves down to pierce the primer.  The fuze is not "all-ways action", but will probably function on a slight angle of impact.

A second small grenade has been recovered which is identical to the previously described small grenade in measurements and type of construction but differs in the following details.  The silk bag which covers the charge of the second grenade is made of bright yellow finished silk.  The main explosive charge is picric acid with a small RDX booster.  The adapter ring is bakelite instead of metal, while a straw tail is used in place of hemp.

The fuze of the second grenade has a black finish, a single safety pin, and a gaine which is crimped to the fuze body, but otherwise is similar in construction and operation to the fuze of the first grenade.

Sling Hand Grenade
  

Overall length: 5 and 7/8 inches
Maximum diameter: 1 and 13/16 inches

Total Weight: 1 pound, 3 ounces
Filling: TNT
Weight of filling: 1 ounce
Delay: 4 or 5 seconds

Color: Black

Description: The sling grenade consists of a steel grenade body, wooden base plug, reinforcing cloth, scratch type friction ignited fuze, wooden fuze seat, wooden spacing ring, and a metal protective cap.

The rough, cast steel, cylindrical grenade body has a hollow projection on its forward end into which the wooden fuze seat and fuze are fitted and secured with glue.  The after end of the body opens directly into the TNT filled explosive cavity of the grenade.  This opening is closed by the wooden base plug, which is glued in place.  The throwing line is attached to the after end of the wooden base plug.

A strip of reinforcing cloth is wrapped around the base plug and the after end of the grenade body in order to help prevent the two sections from pulling apart when a line is used to throw the grenade.  The cloth is lashed securely in place by light line, which is tied around the annular groove in the grenade body and the cylindrical after section of the base plug.

A light, sheet metal cap is sealed over the nose of the grenade with waterproof paper tape.  The wooden spacing ring prevents contact between the fuze and the protective cap.  A flat surface on the side of the ring is coated with the abrasive compound used to ignite the fuze.

The fuze for the sling grenade is made in two sections: a long brass detonator tube and a short igniter head.  This tube is pierced by a single gas port and is crimped to the detonator tube.

Operation: The abrasive on the spacing ring is rubbed against the match head of the fuze to ignite the match composition which initiates the firing train.  The grenade is then thrown by hand or by means of the line attached to the ring in its base.  The delay is from 4 to 5 seconds.




1/2kg Incendiary Hand or Mortar Grenade
  

Overall length: 5.6 inches
Maximum diameter: 2 inches
Body material: Brass

Weight: 1.1 pounds
Filling: White Phosphorus
Delay: 4 or 5 seconds

Description:  This grenade may be thrown by hand or projected with the 50mm grenade discharger, Model 89.  The incendiary filling is contained in a brass body which may have a propelling charge on the base.  The fuze is identical to the one used in the Type 91 and Type 97 fragmentation hand grenades.

The steel propellant container is 1 and 1/4 inches long, 1.02 inches in diameter, and has six perforations in its walls.  It is screwed into the base of the body.  A perforated plug screws into the base of this container and in a cavity in this is a percussion cap.  Two flash holes head through the percussion cap holder to a small quantity of black powder.  A perforated steel disc covers the plug and inside the propellant container proper is a copper cup containing flakes of nitrocellulose propellant powder.

Operation: The firing pin must first be threaded down into the inertia weight.  The safety pin must then be withdrawn.  If the grenade is to be thrown by hand, it is necessary to strike the inertia weight on some hard object thus driving the firing pin into the primer to ignite the delay train.

If the grenade is to be fired from the grenade discharger, or knee mortar as it is sometimes called, the grenade with propellant container is dropped base first into the discharger.  When the trigger mechanism of the discharger is operated, its firing pin strikes the percussion cap igniting the propelling charge which propels the grenade.  Force of setback causes the firing pin in the grenade fuze to compress the creep spring and hit the primer to ignite the delay train.

Next Time: More Imperial Japanese Grenades, and Sabotage Devices

Imperial Japanese Explosives - Land Mines and Grenades (Part 3)

Imperial Japanese Explosives

  

  

Airstrip Mine
 

Type of Explosive: 31 100kg bombs and picric acid

Method of Detonation: Closing electrical circuit or by use of demolition clock.

Description: The bombs were stacked around picric acid blocks in which electrical detonators were inserted.  The entire mine was under a turf-covered piece of sheet iron that would close the circuit and fire the charge if the iron were lifted or depressed.  A clockwork was also inserted to fire charge if iron was not disturbed.

  

  

Improvised Antitank Mine

Type of Explosive: 2 hand grenades, a 2-pound prepared charge of picric acid, and a Mod 99 armor-piercing mine.

Method of Detonation: Pressure on board to fire fuzes in grenades.  Sympathetic detonation relied upon for explosion of main charge.

Description: A prepared picric charge was laid on top of an armor-piercing mine and a hand grenade was set on the two sides.  A board was laid over the top so that pressure would be transmitted to the fuzes of the grenades.

Type JE Antiboat Mine

Diameter: 20 and 1/4 inches

Height: 10.62 inches
Thickness of wall: 3/16 inch
Material of wall: Steel

Weight: 106.5 pounds (not including horns detonator, booster, and wiring)

Weight of filling: 46.5 pounds

Type of filling: Type 98 explosive (HND/TNT N 40/60) with picric acid booster and tetryl detonator.

  

Description:  This is a hemispherical, chemical-horned, all-welded mine.  The outer body forms a hemisphere and has two handles on its upper portion, a central opening on top to take the booster and safety switch, and two horn openings 180 degrees apart. 

The mine is divided internally into an explosive chamber and a chamber containing booster, wiring, safety switch, and horn electrodes.  The division is made by a shallow, saucer-shaped steel section, which forms less than a hemisphere which is pressed into the outer body from the bottom and welded in place.  A plate is then fitted into the bottom of the mine and is also welded in place.  This last-mentioned plate carries a filling plug in its center and is insert 13/16 of an inch to allow clearance for the plug. 

The horns, two in number, appear to be standard lead-acid mine horns.  They are set at an angle of about 65 degrees and project above the level of the mine top; threads are left-handed.  In the firing circuit is a spring-loaded plunger whose upper end projects through the safety switch cover.  A rubber diaphragm in the top of the cover insures watertight-ness but allows the plunger to move. 

There is a tapered, threaded hole in the center of the top of the plunger and a groove around the plunger near the top.  Until the mine is in position a safety fork engages this groove and holds the plunger up against its spring.  The inner end of the plunger is thus withdrawn from between two contacts in the electrical firing circuit and the circuit is incomplete.

Employment: Used on beaches as an antiboat mine.  It can also be used on land as an antitank mine by burying or otherwise concealing it.

Operation: After the mine is laid the safety fork is removed.  The contact plunger moves down under spring pressure and closes the electrical contacts, thus completing the electrical circuit and the mine is armed.  When a horn is crushed an acid vial inside is broken, allowing the acid to drain down onto two plates of a small battery which generates sufficient amperage to fire the detonator.  As the wiring is series-parallel, either horn on being bent will act independently to fire the mine.

Remarks: The Japanese designation is: Small type land mine.

Type JG Antiboat Mine

Method of actuation: Chemical Horn

Weight of explosive: 22 pounds
Type of explosive: HND/TNT 40/60 (Type 98)

Diameter of top opening: 5.1 inches
Diameter of top: 7 inches

 
Mine No. --- Diameter of base --- Height --- Total weight
1 --- 14 and 5/16 inches --- 10 and 1/4 inches --- 57 pounds
2 --- 14 and 9/16 inches --- 10 and 5/16 inches --- 55 pounds
3 --- 14 and 9/16 inches --- 10 and 5/16 inches --- 62.5 pounds
4 --- 14 and 5/16 inches --- 10 and 1/4 inches --- 57 pounds
5 --- 14 and 5/16 inches --- 10 and 1/4 inches --- 52.5 pounds

  

Description:  There are five modifications of the subject mine, each of them being actuated by a single chemical horn screwed into the top.  The mines are either bell-shaped or of a truncated cone shape with an additional distinguishing factor being the location of the welds.  The firing mechanism is similar to the J-XIII; however, a very small detonator is used to initiate the explosive train.

Employment: Used as an antiboat mine for the protection of beaches and reefs; also on land as an A/T mine by camouflaging.

Operation: The mine is laid with the chemical horn installed and a safety pin through the spring-loaded arming spindle.  When positioned properly, the safety pin is removed allowing the spindle to move down and bridge the contacts of the safety switch.

The mine is fired when the chemical horn is crushed or broken.

Remarks: The Japanese designation is: Small type land mine Model 2.

 

Introduction to Hand, Rifle, and Mortar Grenades

  

The Japanese armed forces developed, both before and during the war, a fairly extensive line of hand and rifle grenades.  This type of ordnance is primarily used by ground forces, was developed by the Army, but in the peculiar Japanese military organization, was also used by the Navy ground defense units.

The hand and rifle grenades used by the Japanese, although designed for a large variety of purposes, are similar in a number of respects.  Generally, they are smaller than would be considered adequate by American standards.  Also, observation of them in use has shown that, although explosive charges are usually large enough, effective fragmentation is often not achieved.  In the main, the missiles are lacking in safety factors, and in reliability, the principles used in the igniters being of such character that they may be initiated accidentally and are subject to deterioration because of exposure to moisture.  In the case of grenades of glass construction, the danger of initiation is great.

Rifle grenades are often standard hand grenades adapted for use as rifle grenades by the addition of a tail portion.  Hand grenade igniters are retained, with delay trains removed in some cases.  A large variety of improvised grenades has been found in all Pacific areas.  These grenades have been adapted from such items as small ammunition, small bombs, pipe, paper, and wood.  In general, improvisations were the result of shortage of the manufactured item, and were prepared by inexperienced personnel.  Consequently, they were, in almost all cases, very ineffective and extremely dangerous to use.

Type 91 Hand, Mortar, or Rifle Grenade
  

Overall length: 3 and 3/4 inches
Maximum diameter: 2 inches

Total Weight: 18.8 ounces
Filling: Powdered TNT
Weight of filling: 65 grams
Delay: 6 seconds

Color:
-Body: Black
-Fuze cover: Red
-Fuze: Brass

Description: The case iron body is cylindrical and has 50 serrated segments.  A filling plug screws into the upper end of the body, and a brass fuze screws through this lug.  The base of the grenade is threaded, but not entirely through to the charge.  Into these threads fits the propellant container.

The fuze consists of a brass inertia pellet with a steel firing pin separated from the primer by a creep spring.  The inertia weight is held in the fuze by a light brass cap which is crimped into a cannelure in the fuze body so as to prevent the firing pin from reaching the primer.  The firing pin is threaded itno the inertia weight.  In addition, a double brass safety pin fits through the fuze, preventing the firing pin from reaching the percussion cap.

The delay pellet screws into the base of the fuze and contains a small quantity of granular black powder and a pellet of black powder.  A hole drilled in the side of the fuze contains a fusible plug which melts when the black powder burns, allowing the escape of the gases formed on combustion of the delay train.  The tetryl detonator is contained in a brass tube extending from the base of the fuze to the bottom of the bursting charge.

The steel propellant container is screwed into the base of the body.  A perforated plug screws into the base of this container and in a cavity in this is a percussion cap.  Two flash holes lead to a small quantity of black powder.  Inside the propellant container proper is a copper cup containing flakes of nitrocellulose propellant powder.

When this grenade is used as a rifle grenade, a finned tail stabilizer is screws into the base of the grenade instead of the propellant container.

Operation: The firing pin must first be threaded down into the inertia weight.  The safety pin must then be withdrawn.  If the grenade is to be thrown by hand, it is necessary to striker the inertia weight on some hard object to drive the firing pin into the primer to ignite the delay train.

If the grenade is to be fired from the grenade discharger, the grenade with propellant container is dropped base first into the discharger.  When the trigger mechanism of the discharge is operated, its firing pin strikes the percussion cap, igniting the propelling charge which propels the grenade.  Force of setback causes the firing pin in the grenade fuze to compress the creep spring and hit the primer to ignite the delay train.

To fire the grenade from a rifle, the stabilizer is placed over the launcher and the rifle is fired using the special cartridge.  The shock of discharge forces the striker into the primer igniting the delay.




Type 97 Hand Grenade
  

Overall length: 4 inches
Maximum diameter: 2 inches

Total Weight: 1 pound, 3 ounces
Filling: Powdered TNT
Delay: 4-5 seconds

Color:
-Body: Black
-Fuze cover: Red
-Fuze: Brass

Description: The body is cylindrical with serrations to give uniform fragmentation.  This grenade is identical to the Type 91 grenade except that th ebase of this grenade is solid and therefore cannot take a propelling charge.  It can only be used as a hand grenade.

Operation: The firing pin must first be threaded down into the inertia weight.  The safety pin must then be withdrawn.  As the grenade is to be thrown by hand, it is necessary to strike the inertia weight on some hard object thus driving the firing pin into the primer to ignite the delay train.

Remarks: A Type 97 grenade with an aluminum body has been recovered.

A gray or black grenade, which strongly resembles and appears to be a forerunner of the Type 97 grenade, has also be found.  This grenade employs a fuze of black powder rolled in paper leading directly to the black powder bursting charge.  No detonator is used in the firing train.  The fuze pocket is threaded to take a mechanical fuze of the same size as the fuze used in the standard Type 97 grenade.

Next Time: More Imperial Japanese Land Mines, and Grenades

Imperial Japanese Explosives - Land Mines and Grenades (Part 2)

Imperial Japanese Explosives

  

  

Type 3 (a) Antivehicular and Antipersonnel Land Mine
 

Diameter: 8.6 inches

Height (w/o fuze): 4.13 inches
Height (fuzed): 6.2 inches
Length of fuze: 2.5 inches

Material of mine wall: Terra cotta
Thickness of wall: 7/16 inch

Explosive fillin: Type 88 explosive.  Captured document states bursting charge might also be either ammonium nitrate (50%), TNT (50%); or ammonium nitrate (90%), dinitronaphthalene (10%)

Weight of explosive: 4 pounds, 8 ounces

Total weight of mine: 11 pounds, 6 ounces

  

Color and markings: Brown


Description: The mine is circular with a slightly concave top and a moderately convex base.  The mine case is made of earth-colored terra cotta.

The outer surface has a thin dull glaze while the inner surface is covered with a thin coat of lacquer.  A rubber fuze seat is sealed in place in a hole in the center of the top of the mine.  The explosive filler is contained in a light rubber bag inside the mine.

The fuze body, cover, plunger, and striker support are made of bakelite.  The springs, percussion hammer, striker, and the release fork are the only metal parts in the mine and with the exception of the release fork, all are contained inside the fuze.
 

Employment: May be used as an antivehicular or antipersonnel mine.
 

Operation: The mine is place in the desired location and the safety pin is withdrawn.  The fuze may then be rigged to fire either by pull or pressure.

The percussion hammer located within the fuze is held in place by a release fork to which a trip wire may be attached.  When the wire is pulled (22-pound pull required), the fork releases the hammer which is forced downward by the hammer spring.  The hammer hits the striker forcing it through its bakelite holder into the percussion cap.

When pressure of 20-25 pounds is applied directly on the head of the fuze the plunger spring and hammer spring are compressed causing the hammer head to exert pressure on the hammer release fork.  When the plunger is further depressed a groove in its inner surface comes down to the level of the hammer release fork.  The pressure of the hammer head cams out the fork.  The hammer is released and hits the striker which in turn pierces the detonator.

Remarks:  A larger model of this mine exists, and differs from it only in size.  The larger version has a diameter of approximately 10 and 1/2 inches.

  

  

Type 3 (b) Antivehicular and Antipersonnel Land Mine

Diameter: 7 and 1/8 inches

Height (w/o fuze): 5 inches
Height (fuzed): 7.5 inches

Material of mine wall: Wood
Thickness of wall: 9/16 inch

Explosive fillin: Type 88 explosive.  Captured document states bursting charge might also be either ammonium nitrate (50%), TNT (50%); or ammonium nitrate (90%), dinitronaphthalene (10%)

Weight of explosive: 4 pounds, 8 ounces

Total weight of mine: 6 pounds, 4 ounces (w/o fuze)

  

Color and markings: Unpainted wood

   

Description: The mine is simply a wooden box with dovetailed sides to which top and bottom closing pieces have been fastened by screws and nails respectively.  It is a standard mine manufactured to standard specifications and employing the Type 88 explosive charge and its rubber container, the threaded rubber fuze seat, and the same type fuze used in the Type 3 (a) land mine.

The threaded rubber fuze seat is nailed to the bottom side of the top closing piece beneath a hole provided to allow insertion of the fuze.

Employment: May be used as either antivehicular or antipersonnel mine.

Operation: Same as Type 3 (a) land mine.

Beehive Antipersonnel Land Mine

    

Diameter at base: 8 inches

Height (w/o fuze): 4.5 inches
Total weight: 17 pounds (approximate)
Thickness of mine wall: 3/8 inch

Explosive filling: TNT
Weight of explosive: 5 pounds (approximate)

 

Color and markings: Black
  

Description: The mine is hemispherical in shape and its surface is uniformly serrated.

The central hole in the top of the mine is internally threaded to receive one of two fuze adapters.  The first adapter takes either the plastic fuze used in the Type 3 (a) ceramic and Type 3 (b) wooden land mines, or the Type 88 instantaneous artillery fuze from which the centrifugal detents have been removed.  The second adapter is constructed to take the fuze employed in the Type 93 tapemeasure mine.

Both the serrations of the mine case and the thickness of the wall (3/8 inch) indicate that this mine was to be used as an antipersonnel weapon.

Employment: Antipersonnel mine

Operation: The operations of the Type 93 land mine fuze and the Type 3 (a) ceramic land mine fuze are discussed under their respective mines.

The Type 88 artillery projectile fuze from which the centrifugal detents have been removed is fired by pressure on the firing pin head.  Pressure on the firing pin head compresses the anticreep spring and the firing pin is forced into the primer.

5kg Hemispherical Antitank Land Mine

 The 5kg hemispherical A/TK mine is a weapon designed to help overcome the shortage of A/TK weapons and armored vehicles which the Japanese forces experienced during the war.  It is a suicide weapon, intended to be placed against an armored vehicle either by hand or by means of a pole or lines.

The mine is hemispherical in shape, black in color, with the fuze mounted opposite the flat face.  It is equipped with a straight projection to which a pole may be lashed, and with four eyelets to which lines may be attached.

The mine is detonated by the same fuze as that used in the Type 99 magnetic A/TK mine.  No specimens of this mine were found outside of the Japanese homeland, very few of them having been produced.

    

Bangalore Torpedo and Igniter

  

Dimensions: See Drawing
Total weight of torpedo: 10 pounds

Weight of filling: 3 pounds
Type of filling: TNT (36.4%), Cyclonite (63.6%)


Color and markings:
-Torpedo tube: Brown with red band onboard of externally threaded end, white triangle near midepoint of tube, and eleven inches inboard of red band on opposite side from white triangle is (see below)

  

Description:  The igniter system consists of two pull igniters screwed into an igniter holder which fits into the igniter locking collar.  The rings of the igniters are connected by lines to the lanyard holder.  The igniters are simple match composition pull igniters with a black powder delay of 8 seconds, an initiant, and a base charge of tetryl.  When shipping, the steel nose cap is threaded onto the igniter as shown in drawing.

The torpedo proper is a steel tube with shoulders welded to both ends.  One end is internally threaded to take the igniter locking collar and the other end is threaded externally to take the pointed nose cover.  When shipped the tube has a cap screwed over one end and a male plug threaded into the other.

Employment: The Bangalore torpedo is used by the Japanese to demolish barbed wired entanglements.  It can also be used as a booby trap, actuated by pull.

Operation: The caps are removed from the ends of the tube, the pointed nose cover is screwed onto one end, and the igniter locking collar into the other end.  The torpedo is now ready for use.  When the torpedo is placed the safety pin is removed and the firing lanyard is pulled sharply.  Personnel can take cover in the 8 seconds delay period.

The pulling of the firing lanyard pulls the match composition through the abrasive.  The flash starts the black powder which after 8 seconds delay fires the initiant and tetryl base charge and the torpedo charge.




Pressure and Traction Land Mine
  

Overall length: 12.5 inches
Overall width: 9.5 inches
Overall height: 7 inches

Weight of filling: 2 pounds
Type of explosive: Three blocks picric acid or TNT detonator of igniter inserted in center block.



Description: The mine consists of a wooden box, the lid of which is held in place against the internal flanges on the top by four stout springs (one in each corner).  A wooden block is secured by two bolts to the underside of the lid and serves to operate the pull igniter by pressure exerted on the cover.

The explosive charge is in a separate container with the igniter and detonator inserted in the center block.  A pull wire extends from the igniter over to the wire rod directly under the wooden block attached to the underside of the lid.

To this wire rod are attached a trip wire which passes out through the cover to be secured to a tree or other suitable object and an antilifting wire attachment which passes through a hole in the base of the box and is secured to a peg.  The igniter contains ignition composition and a pellet of powdered glass in red cement.

Employment: Used as an antitank or antipersonnel mine.

Operation: The mine will function by either of three methods:
-Pressure exerted on the lid,
-Tension exerted on the trip wire; or
-By lifting the mine to operate the antilifting device.

In all instances the wire rod is moved which pulls the wire leading to the igniter.




Friction-Fuzed Land Mine
  

Overall length: 13 inches
Overall width: 3 inches
Overall height: 2.37 inches

Weight of filling: 3.5 pounds

Type of explosive: Five blocks picric acid or TNT detonator of igniter inserted in end block.

Description: The mine consists of a wooden box, the sides of which are 0.59 inch thick.  A wooden partition block inserted 4.25 inches from the unfilled end of the box serves to hold the five blocks of explosive in place and also to secure the igniter in position.  To the igniter is attached a trip wire which extends out through the end of the box and is secured to a tree or other suitable object.

A safety device, the exact nature of which is unknown but reported to consist of a bottle cap, is incorporated on the outside of the box at a point of egress of the trip wire.  The antilifting device consists of a wire attachment which passes through the base of the box and is secured to a peg driven in the ground.

Employment: The mine is buried 1 to 2 inches below the surface and used as either an antitank or antipersonnel mine.

Operation: The mine can function by either a tension exerted on the trip wire or by lifting the mine to operate the antilifting device.  In both instances the pull igniter is fired which in turn detonates the explosive charge.




Improvised Land Mine
  

Dimensions: A box 5 and 5/8 by 4 and 1/4 by 3 and 1/4 inches
Material: Tin
Color: Silver
 
Description: The mine consists of a rectangular box with a cover securely fastened by friction tape.  Two holes are roughly punched in the cover through which a grenade fuze or detonator projects.  The grenade fuze projects approximately 3/4 inch, projection of detonator is unknown.

Contained in the box are one Japanese Type 91 hand grenade and twelve blocks of 1/3 aluminum powder and 2/3 RDX.  Each block is 1 and 1/2 inch by 3/4 inch and wrapped in waxed paper.  Color is black.  The grenade and blocks, 1/3 aluminum powder and 2/3 RDX, are firmly held in place by waxed paper.

Employment: Can be used as an antitank mine when fuzed with the armed grenade.  With a pull or tension detonator it can be used as an antipersonnel mine or booby trap.

Operation:
-As an antitank mine: Safety pin on fuze is removed.  When it is hit by a sharp blow the striker breaks a shear wire and penetrates the primer.  After a delay of 4 to 5 seconds the bursting charge explodes setting off the charge.

-As an antipersonnel mine or booby trap: A pull igniter with detonator is inserted into the charge.  When the trip wire is pulled, the flash will fire the detonator which in turn sets off the explosive and hand grenade.

Next Time: More Imperial Japanese Land Mines, and Grenades

Imperial Japanese Explosives - Land Mines and Grenades (Part 1)

Imperial Japanese Explosives

Introduction

  

Although the use of land mines by the Japanese forces was not as extensive as it was in Europe, land mines were important defensive weapons in the Pacific war.  Also, because of the Japanese lack of effective anti-tank artillery and the inequality of armored forces which was everywhere existent, mining and similar tactics became a mainstay of defense against mechanized equipment.  This was more apparent as Allied forces approached the Japanese homeland, and the defense forces were better equipped than those in the outlying islands had been.

Three features of the Japanese land mining methods were especially important.  The first was the relatively small number of standard, mass-produced mines and firing devices.  This lack of variety in standard mines led to a large amount of field improvisation of land mines and other defense devices, using ordnance and other types of explosives originally designed and manufactured for other purposes.

The second outstanding feature of Japanese land mining was the prevalent use of extremely large charges for all types of land mines.  Bomb, sea mines, depth charges, and even torpedo warheads were used extensively with all types of detonating equipment.  The use of these large charges, although it was wasteful, was the result of inability to use heavy explosive ordnance for its intended purpose, and rendered the potential danger area of land mines very great.

The third was the emphasis which was placed on various types of controlled mines.  This tendency was in keeping with the use of improvised mines, controlled mines being much easier to improvise than enemy activated mines.  Controls ranged all the way from elaborate electrical systems to crude, hand-operated, suicide devices.  Firing devices operated by simple lanyards or poles were common.

Japanese mining techniques were characterized by an almost complete lack of uniformity.  Land mining policies seemed to have been formulated by local authorities and indicated that little or no information was available, and that training was inadequate.  Thus, the Japanese land-mining program was far from being as effective as it should have been tactically and did not often cause serious difficulty to advancing Allied forces.

  

  

Type 93 Antitank and Antipersonnel Land Mine
 

Diameter: 6 and 3/4 inches

Overall Height: 1 and 3/4 inches

Weight: 3 pounds

Weight of explosive: 2 pounds

  

Type of explosive: Solid ring main charge of cast picric acid with inner ring booster of pressed powdered picric acid containing a central hole 5/8-inch in diameter to house fuze.  Explosive completely covered by layer of paper, shellacked to the explosive and waxed externally.

  

Color and markings: Olive drab with narrow red ring around brass plug.  Mine may have numerals (such as 16.9) in white on top indicating date.

Meaning safe inscribed on top of safety cap and on lug of safety washer.

Description: The mine is circular with a slightly domed top and flat bottom.  It is constructed of an upper and lower section of sheet metal secured together by four heavy corrugations in the walls which serve as threads.  The overlap of the walls of the two sections is sealed with a bituminous paint.  The interior of the container is painted with a black enamel.  Soldered on the inside of the bottom of the lower section is a brass disc 1 and 9/16 inches in diameter, having a threaded collar for the insertion of the fuze.

The central hole in the upper section is reinforced with a brass collar threaded to receive the brass plug.  A thin leather washer fits between the brass plug and the collar to seal the mine.

Two brass rings are fastened to two opposite sides of the upper section by means of a soldered metal strip.  Drag ropes may be fastened to the rings.

The fuze assembly consists of a striker held under spring pressure by a shear wire, a percussion cap, a primary detonator, and a larger secondary detonator all incorporated in the fuze body which is threaded on the lower end to screw into the collar in the bottom of the mine. 

A safety cap is screwed into the upper end of the striker until the mine is laid.  An additional safety feature is a brass cylinder with attached washed which fits over the brass safety cap and rests on top of the fuze body, the washer fitting under the leather washer of the brass plug.
 

Employment: Antipersonnel and antitank.  The Japanese have two sizes of shear wire for this mine.  One for antipersonnel use shears at 70 pounds, the other, for antitank use shears at 250 pounds.  These mines have been found buried upside down with additional explosives placed beneath them to increase their effect.  The A/P fuze has a black upper body.
 

Operation: With the safety devices removed, any load on the cover of the mine causes the brass plug to press down on the striker.  If the pressure is sufficient, the shear pin is sheared.  This frees the striker which, under pressure of the spring, strikes the percussion cap initiating the detonating system.

  

  

Anti-Vehicular "Yardstick" Land Mine

Overall length: 36 inches    

Diameter: 3.35 inches by 1.8 inches (oval)

Total weight: 10 and 1/2 pounds

Weight of filling: 6 pounds
Weight of each explosive block: 3/4 pound

  

Type of explosive: Eight identical blocks of picric acids cast in paper container, coated with paraffin.  Each block molded on one end to take fuze so that two blocks placed with molded ends together completely enclose fuze.

  

Color and markings: Mine case painted olive drab over undercoat of black.  Interior painted with black lacquer.

Designation

(fuze top portion) stenciled vertically in red characters approximately 7/8-inch tall on one side, and the corresponding marking

(fuze bottom portion) in smaller characters about 1/2-inch tall stencilled on reverse side.
  

Description: The mine is an oval tube formed by two halves of sheet steel welded together with continuous welds and closed at both ends by steel caps held in place by single screws.  One of the caps has a hole to take the safety wire, which is a single wire extending the length of the mine and passing through all the fuzes.  A spring clip holds the safety wire in place.

The explosive blocks flattened on one side do not completely fill the mine case.  The space left between the flat side of the blocks and the wall of the case accommodates the protruding heads of the fuzes and also allows space for the side of the case to be depressed on the fuzes by the passage of a vehicle over the mine.

The fuze consists of a short, cylindrical body which houses the striker release plunger, the striker housing which contains the striker and striker spring, and the gaine.  The gaine and striker housing are identical in external appearance and screw into the sides of the cylindrical fuze body in diametrically opposite positions.

The striker release plunger is a split pin with an enlarged flat head.  It is positioned in the fuze body by a copper shear wire.  A second hole 90 degrees from the shear wire hole accommodates the safety wire.  The lower end of the plunger is split by a slot, the width of which is increased on the inner end.

Employment: This mine is used as an anti-vehicular mine.

Operation: After the safety wire is removed and burying plug is screwed in, the mine is buried.  A vehicle passing over will crush the case and thereby apply enough pressure on the top of the fuze to break the shear wire and depress the striker release plunger.  As the enlarged portion of the slot comes opposite, the spring-loaded striker moves across through the opening and into the primer cap.

Type 99 Armor-Penetration Land Mine

  

Overall Length: 4.75 inches (circular)

Overall width: 1.5 inches
Total weight: 2.5 pounds
Weight of filling: 1.5 pounds
Fuze delay: 8-10 seconds

Type of explosive: Eight cast blocks, 50-50 RDX-TNT shaped to form circle. Individual blocks wrapped in wax paper.

 

Color and markings: Khaki.

Stenciled in black on body

Stencilled on opposite side
  

Description:  The mine resembles a canvas cloth bag, disc shaped, with a snap-fastened flap on the outer edge for inserting the eight blocks of explosive.  Opposite the filling flap on the outer edge of the mine, is a metal adapter which is externally threaded to receive the fuze. 

Four equally spaced permanent magnets are attached by khaki webbing to the outer edge of the mine body.  The mine is packed two to a wooden box complete with wooden shipping plugs in the fuze adapters.  The fuzes are enclosed in tubular metal cases sealed with a paper band and tear string.  For carrying on the field, the mines are packed individually in a khaki-colored cloth pouch. 

The fuze contains two springs, a compression spring and a firing pin spring, the latter of which is contained in a firing pin sleeve.  Four steel retaining balls fit into holes in the firing pin sleeve and notches in the firing pin, retaining the position of the firing pin.  A fuze cap provides a base for the first spring and is grooved on the inside about one-third of the way up from its base. 

There is a safety pin which passes through the fuze body just below the base of the safety cap and between the striker and the percussion cap.  The powder delay train threads into the base of the fuze body, and the detonator tube threads over the base of the delay train container.

Employment: Used as antitank or antivehicular mine, or against armored fortifications.

Operation: The fuze is carried separately and is secured to the mine by a locking ring.  In use, the safety pin is pulled, the fuze cap given a sharp rap, and the mine either placed on or tossed on armor plate within a range of ten feet. 

When the fuze cap is forced downward against the compression spring, its groove aligns with the retaining balls.  The tension of the firing pin spring forces the retaining balls into this groove and also forces the striker down onto the percussion spring.

Remarks: Test detonations of this mine indicate a distinct "Monroe Effect" at the junction of the inner edges of the explosive blocks.  One mine will produce complete perforations in plate up to 1 inch thick.  The mines are frequently coupled together and when so used, will penetrate 1.5 inches of steel plate.

Lunge Mine

Overall length: 78 inches (including handle and legs)
Total weight: 14.3 pounds (mine body and handle)
Length of body: 11.6 inches
Diameter at base: 8 inches
Weight of body: 11 pounds (including explosive)

Length of handle: 59 inches
Diameter of handle: 1 and 1/4 inches
Weight of handle: 3.3 pounds
  

Explosive filling: Crude TNT

Weight of filling: 6.6 pounds

 

Description: The mine consists of a conical shaped hollow charge, with a wooden handle at the apex of the cone and three metal legs welded to the base.

The conical charge is housed in a steel container.  Fitted into the base of the charge is a hollow, truncated cone designed to give the mine the increased power of penetration of this hollow charge.  A well in the apex of the charge contains the detonator.

The wooden handle has a steel striker fitted in one end.  This end is encased in a metal cylinder and is held there by a safety pin and a copper shear wire.  The cylinder is attached to the neck of the charge container by a threaded connecting ring.

Three metal legs 6 inches long are welded to the base of the charge container at 120 degree intervals.  They guarantee the proper stand-off to obtain the maximum effect from the hollow charge.

Employment: Used as an antitank weapon.  Capable of penetrating 6 inches of steel plating.

Operation: The operator pulls out the safety pin, then uses bayonet tactics, the left hand at the center of the handle, the right hand at the after end, as he lunged forward.  When the legs of the mine strike the target, the handle is driven forward breaking the shear wire, and the striker is driven into the detonator initiating the explosion of the mine.
    

Suction-Cup Mine

Overall length: 66 and 3/8 inches (including handle and cups)
Total weight: 7 pounds, 8 ounces (mine body and handle)

Length of body: 5 and 5/16 inches (including cups and handle holder)
Diameter of body: 4 and 3/8 inches
Weight of body: 5 pounds, 8 ounces filled (including suction cups)

Total length of handle: 59 and 5/8 inches (2 pieces)
Diameter of handle: 1 and 7/16 inches

Explosive filling:
-RDX: 53%
-TNT, 47%

Description: The mine body is made of a black, sheet metal, longitudinally welded, cylinder, having a flanged metal cap spot-soldered over each end.  Soldered to the circumference of the forward end, 180 degrees apart, are two metal loops.  Into each loop is fitted a solid rubber plug, the forward end of which is made into a shallow suction cup.  These suction cups are held in place by metal pins and extend just forward of the leading edge of the mine body.

A wooden handle, consisting of two pieces held together by a metal sleeve, fits into a hollow extension welded to the top of the mine body.

The initiating element, consisting of pull igniters, safety fuse, prima cord, and blasting caps, is rigged in duplicate and extends the length of the handle into a well in the top of the mine body.  Four blasting caps are used, two being crimped to the forward end of the safety fuse and two being crimped to the forward end of the prima cord. 

If only one section of the handle is used the prima cord may be omitted; in which case the blasting caps of the safety fuze are place directly into the well of the mine.  The initiating element is lashed to the handle of the mine with light line.

Employment: These mines are known to have been successfully used against parked aircraft.

Operation: The suction cups hold the mine in position when it is placed against a smooth surface.  The friction igniters are pulled simultaneously, starting the safety fuze burning.  This gives an estimated delay of 10-15 seconds, after which the upper blasting caps, the primacord, the blasting caps in the charge, and the main charge are initiated in sequence.




Dutch Antitank and Antipersonnel Land Mine
  

Overall height: 3 and 1/2 inches
Height of body: 2 and 7/8 inches
Diameter of body: 8 and 1/8 inches
Diameter of cover: 8 and 1/4 inches
Wall thickness: 5/32 inch

Weight of filling: 5 and 1/4 pounds
Total weight: 9 and 1/2 pounds
Type of filling: TNT

Color and markings: Olive drab overall with "P.W. 2-41" in red across top of both cover and mine body.  "P.W. 2-41" inscribed on the fuze head.

Description: The body is of pressed steel construction with a crimped-on base.  The cover is also pressed steel with four side slots corresponding with screw holes in the body which take the small fixing studs.

In the center of the cover is a brass plug.  A helical spring holds the cover away from the body.  The igniter and detonator assembly screws into the top of the body of the mine.  The striker is spring-loaded and is held off the cap by the 1/16-inch diameter, soft copper shear wire.  There is no safety pin.

The detonator assembly consists of a detonator tube enclosed by an outer tube, and a primer.

Employment: The Japanese use the mine mainly against personnel, laying them in narrow trails, on beaches, and at entrances to bivouac areas.  Normally they lay it on top of the ground.

Operation: The movement of the cover is regulated by the size and position of the slots.  Pressure on the cover is transferred from the brass plug on to the striker head, thus shearing the shear wire and allowing the spring to drive the striker into the cap thereby detonating the mine.


A load of 50 pounds is sufficient to shear the copper shear wire.

Next Time: More Imperial Japanese Land Mines, and Grenades

Imperial Japanese Navy Explosives - Bombs (Part 8)

Imperial Japanese Navy Explosives

Type 0 Model 1, Type 0 Model 2, and Cardboard Type Sea Markers

  

Fuzes: None
  

Type 0 Model 1

Overall Length: 12 and 1/2 inches

Length of body: 7 and 1/2 inches

Diameter of body: 3 inches

Thickness of wall: 1/64 inches

Material of wall: Sheet Steel


Cardboard type

Overall Length: 12 and 1/2 inches

Length of body: 7 and 1/2 inches

Diameter of body: 3 inches

Thickness of wall: 1/16 inches

Material of wall: Cardboard

  
 

Type of suspension: Dropped by hand

Suspension lug: None


Type 0 Model 1
Length of tail: 5 inches
Width of tail: 4 and 1/4 inches
Width of tail fins: 1 and 7/8 inches
Dimensions of tail struts: None

 Material of tail: Light tin

Cardboard type

Length of tail: 5 inches
Width of tail: 3 inches
Width of tail fins: 1 and 1/4 inches

Dimensions of tail struts: None

Material of tail: Cardboard
  

Type of filling: Aluminum powder, containing 6.5% zinc.  1 ounce covers 118 square feet.
No explosive

Type 0 Model 1

Weight of filling: 0.7 pound

Total weight of bomb: 3.5 pounds
Charge/weight ratio: 20%

Cardboard type

Weight of filling: 1 pound

Total weight of bomb: 3.5 pounds
Charge/weight ratio: 20%

 

Color and markings: Aluminum color.  Japanese inscription printer on a paper label which is glued to the body of the marker. (Instructions for operation of marker.)
 

Construction of body:
-Type 0: A sheet steel cylindrical body is fastened to the steel nosepiece by four punch marks.  The tail cone and body are joined by a thin disk of light wood secured by four tacks in each component.

-Cardboard type: A hollow-steel nosepiece is secured to a paper body by a strip of adhesive tape.  The body is reinforced by cardboard strips.  A cardboard tail cone is fastened to the body by adhesive tape.  Four cardboard fins are glued to the tail cone.

Situated in the hollow section of the steel nosepiece is a wooden cylinder 1 and 7/16 inches in diameter.  Fastened to this cylinder is a small wooden disk the same diameter as the inside of the body.  Located between this nose disk and the wooden disk in the tail is a connecting wooden pin 4 and 3/4 inches long.


Operation:
-Type 0: On impact with the water, the plug in the nose is forced up into the body, forcing the tail portion to be freed from the body, thereby scattering the aluminum powder.

-Cardboard type: On impact with water the container breaks up and releases the aluminum powder.

Remarks: Type 0 Model 2 is similar in construction to Model 1.  It is painted yellow overall and contains a filling of dark green powder which produces a green slick on the water.

  

  

Type 3 No.6 Target Marker Bomb
 

 
Fuzes: A-1 or A-3 series

Overall Length: 42 and 1/4 inches

Length of body: 21 inches

Diameter of body: 9 and 1/2 inches

Thickness of wall: 1/8 inches

Material of wall: Steel
 

Type of suspension: Horizontal

Suspension lug: Normal Navy suspension lug

Length of tail: 21 and 1/4 inches
Width of tail: 13 and 1/4 inches
Width of tail fins: 6 inches

Dimensions of tail struts:
-Length: 9 and 1/4 inches
-Width: 1 and 1/2 inches
-Thickness: 1/16 inch

Material of tail: Steel
  

Type of filling: The filling consists of 152 phosphorus-filled steel pellets contained in three cylindrical steel canisters.  Each canister is filled with pellets and the space not occupied by the pellets is filled with white phosphorus.  The canisters are covered with a heavy wax coating.  There is a charge of Type 98 explosive in the nosepiece of the bomb.
  

Weight of canisters:
-Canister One: 68 pellets - 56 pounds
-Canister Two: 56 pellets - 37.5 pounds
-Canister Three: 28 pellets - 13 pounds
  

Dimensions of canisters (Length x Diameter):
-Canister One: 7 inches by 8 and 1/4 inches
-Canister Two: 5 and 3/4 inches x 8 and 1/4 inches
-Canister Three: 3 inches x 8 and 1/4 inches

Dimensions of pellets:
-Length: 2 and 1/2 inches
-Diameter: 1 and 1/2 inches

Weight of filling: 107 pounds
Total weight of bomb: 155 pounds
Charge/weight ratio: 69%
  

Color and markings: The bomb is grey overall with a red band on the nose and red tail struts.  Four longitudinal grooves are painted red.
 

Construction of body: A cast-steel nosepiece is attached to a longitudinally welded steel body by a continuous weld.  The nosepiece contains a gaine well surrounded by an explosive charge which in turn is surrounded by a wooden filler plug.  The body has 4 external longitudinal grooves 90 degrees removed from each other.  The tail cone is welded to a collar which fits into the body and is held there by a single row of 16 screws.
 

Construction of tail: The tail cone is constructed of 1/8-inch steel and is welded longitudinally.  Four steel fins are welded to the cone and are braced by a single set of box-type struts.

  

  

 

Type 2 2kg Target Indicator

    

Fuzes: None
Overall Length: 17 inches

Length of body: 11 and 3/16 inches

Diameter of body: 3 inches

Thickness of wall: 3/16 inches

Material of wall: Bakelite
   

Type of suspension: Horizontal

Suspension lug: A steel suspension ring is attached to a steel band by a soldered tin strip.  The steel band fits tightly around the bomb body.

Length of tail: 4 and 7/8 inches

Width of tail: 5 inches
Width of tail fins: 1 and 9/16 inches
  

Dimensions of tail struts:
-Length: 3 and 1/8 inches
-Width: 7/16 inch

Material of tail: Sheet Tin
  

Type of filling: F.M. (titanium tetrachloride)

Weight of filling: 1 pound, 7 and 3/4 ounces

Total weight of bomb: 3 pounds, 14 ounces
Charge/weight ratio: 37%
  

Color and markings: Black body and tail.  No other color or markings present.
  

Construction of body: The bomb body is of molded bakelite construction with an opening in the after end only.  This opening is threaded to receive a bakelite stopper, the union being sealed by a black rubber washer.  The stopper is threaded internally to receive a bakelite tube which extends nearly the complete length of the bomb body.  The after end of the stopper is a slightly tapered tube and a rubber tube is cemented over it.

Cemented into the after end of the rubber tube is a glass tube through which the bomb is filled.  When the bomb is approximately two-thirds filled with liquid F.M. the glass tube is heated and sealed off.  A small wire is attached to the glass tube at the point of sealing.  Each of the cemented unions is reinforced with a wire wrapping.

A ballistic cap is glued to the nose of the bomb.  The cap is made of heavy paper and is filled with fine iron fillings to make the bomb nose heavy.

Construction of tail: The tail fins are made of sheet tin.  Pairs of adjacent fins are stamped from the same piece of metal and soldered to the forward end after circular struts.  The edges of the fins are strengthened by having a one-eight-inch turn-back.  The after circular strut (width: 1 inch; diameter: 1 and 7/8 inches) is similarly strengthened.

The forward circular strut (width: 9/16 inch; diameter: 1 and 1/16 inches) is of lighter gage tin and is secured to the fins by soldering except for one free end which is secured by a bolt and nut after the fins are assembled to the bomb.  To insure positive seating of the fins, a rubber insert extends half-way around the inside of the forward circular strut.  A single set of box-type struts (length: 3 and 1/8 inches; width: 7/16 inch) is located at the after extremities of the fins.

Operation: The bomb is released from the plane and the case fractures on contact with the target.  The smoke mixture is dispersed.

2kg Window Bomb

  

Fuzes: Pull igniter

Overall Length: 37 inches

Length of body: 37 inches

Diameter of body: 1 and 3/4 inches

Thickness of wall: 1/32 inches

Material of wall: Sheet Steel
 

Type of suspension: None, hand thrown

Suspension lug: None

Length: 12 inches
Width of tail: 2 and 7/8 inches
Width of tail fins: 9/16 inches

 

Dimensions of tail struts:
-Length: 2 inches
-Width: 3/8 inch
-Thickness: 1/32 inch

Material of tail: Sheet Steel

Type of filling: 250 paper strips, cylinder containing iron pyrite

Weight of filling:
-Paper strips: 10 ounces
-Iron pyrite and cylinder: 20 ounces

Total weight of bomb: 4 pounds, 7 ounces
 

Color and markings: Grey overall.  Two yellow labels.  One gives instructions for use, the other the following: "Silver paper scattering bomb, manufactured October 1944, Navy Air Force Arsenal"
  

Description:  Bomb consist of a nosepiece, body, and end cap.  Nosepiece is made of wood and has a hole in the center to accommodate the string attached to the pull igniter. End of nosepiece is sealed with a paper disk which is removed when the bomb is to be used.  Nosepiece is secured to the body by six nails.  Body is of light sheet metal construction, soldered longitudinally.  After end is closed by an end cap of similar metal and held in place by a sealing tape.

Filling of the bomb case consists of 250 metal coated paper strips and an inner cylinder which contains the delay element and ejection charge.  Inner cylinder is in the front end of the case.  It is of light sheet metal construction and soldered longitudinally.  A metal disk closes the nose end and another metal disk is soldered in place 1 and 5/8 inches from the tail end.  Space between the two disks is filled with iron pyrite to make the bomb nose heavy. 

Each disk has a 1/2-inch hole in the center through which a metal tube is inserted.  This houses a standard type pull igniter such as is used in the 5 kilogram parachute flare.  An 11 inch length of safety fuse is crimped into the after end of the igniter is led to an annular bag containing smokeless powder.

The 250 paper strips are just after of the inner cylinder.  Two L-shaped metal strips placed back to back hold 125 strips each.  Four heavy cardboard strips surround the paper strips to insure their smooth ejection.  The paper strips are covered on one side only by a metal foil.

Operation: The cotton tab on the nose is pulled, exposing the pull igniter cord.  This cord is pulled and the striker hits a flash cap which ignites the safety fuse.  The bomb is thrown from the plane.  The safety fuse burns for 40 seconds and sets off the smokeless powder which ejects the paper strips.

"Baka" Piloted Rocket Bomb

Bomb Data
Overall length: 19 feet, 10 inches
Wingspread: 16 feet, 5 inches


Description: The "Baka" bomb is a suicide weapon designed to be controlled by a human pilot.  It is carried beneath the fuselage of a bomber and released near its target.  Three rocket motors provide propulsion after release from the mother plane.  The entire explosive content of the Baka bomb is contained in the warhead in the nose.


Warhead Data
  

Fuzes: A-3(g), B-9(a), B-10(a), two of each.
Overall Length: 68 and 1/2 inches

Diameter: 23 and 1/2 inches

Thickness of wall: 1 and 1/4 inches

Material of wall: Steel

Suspension: The warhead is secured to the fuselage of the "Baka" bomb by four brackets welded to the base plate.

  

Type of filling: Trinitroanisol

Weight of filling: 1,135 pounds

Total weight of warhead: 2,645 pounds
  

Color and markings:  Grey overall.  Green band around nose, a brown band adjacent to it.
 

Description: The warhead is of one-piece machined steel construction.  It has parallel sides and an ogival nose.  The nose fuze pocket is 8 and 1/2 inches deep.  The after end of the warhead is closed by a base plate.  Four tail fuze pockets are grouped around a central threaded hole in a slightly raised portion of the base plate.  The center hole accommodates an arming device which the pilot operates to arm the four tail fuzes simultaneously.
    

Type 3 and Model 10 Bomb Launching Devices

Type 3

Overall Length: 40 and 1/2 inches

Maximum Diameter: 7 and 7/8 inches

Model 10

Overall Length: 33 inches

Maximum Diameter: 7 and 7/8 inches

Description: Both motors are designed as propulsion units for 60-kilogram ordinary or land-use bombs.  The motors are used to propel these bombs from crude V-shaped wooden troughs for land bombardment.  The motors are interchangeable and may be used on either the 60kg ordinary or land-use bomb.

Type 3

Weight of complete round: 92 pounds

Weight of propellant: 25 pounds
Length of propellant stick: 18 and 1/8 inches
Depth of propellant stick: 3 and 5/16 inches
Weight of ignition charge: 2 ounces

Model 10

Weight of complete round: 52 pounds

Weight of propellant: 13 pounds
Length of propellant stick: 10 and 1/4 inches
Depth of propellant stick: 3 and 5/16 inches
Weight of ignition charge: 2 ounces

Propellant: The propellant charge consists of three sticks of 343 D.T.2 and 343 special D.T.2 (code designation) for the Model 10 and Type 3, respectively.  The chemical analysis of 343 D.T.2 is 65% nitrocellulose, 30% nitroglycerine, 3% ethyl centralite, and 2% sodium chloride.  The chemical analysis of 343 special D.T.2 is not known but probably involves a small variation of 343 D.T.2.  The complete Japanese designation for 343 D.T.2 is Type 93 Mk 2 propellant.

Ignition: The propellant is ignited by an electrical squib.  Current is supplied by a hand generator.

Launcher: A crude V-shaped wooden trough mounted on a bipod forward and a steel base plate aft.  The angle of elevation can be varied.

Remarks: The variation in the size of the two motors is possible a means of varying the range.

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