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.

Next Time: Imperial Japanese Land Mines

Imperial Japanese Navy Explosives - Bombs (Part 5)

 
Imperial Japanese Navy Explosives



 

Type 2 No.6 Mk 21 Bomb Model 1

 

Fuzes: D-4(a)

Overall Length: 41 inches

Length of body: 38 inches (w/ nose piece)

Diameter of body: 9 and 1/2 inches

Thickness of wall: 1/16 inches

Material of wall: Steel
 

Type of suspension: Horizontal

Suspension lug: Normal Navy type suspension lug

Dimensions of tail struts: None

Material of tail: Sheet Steel
 

Type of filling: 40 1kg  high-explosive hollow-charge bombs

Weight of filling: 88 pounds

Total weight of bomb: 132 pounds

Charge/weight ratio: 66%
 

Color and markings: Gary overall.  One inch green band on nose.  Brown band just aft of green band.  Two 1/2-inch white bands on body marking the position of binding straps.
 

Description: The canister consists of a blunt-nose assembly and a light tail piece, around which are fitted three steel segments held together by two circumferential metal retaining bands.  Two steel wires, which are attached to the nose, run longitudinally along the canister and pass through the buckles of the bands locking them together.

The buckles open automatically when the wires are withdrawn.  The nose assembly is constructed of two pieces held together by four lead sealing strips.  The forward piece is hollow and has a fuze pocket.  The after piece contains a wooden disk.  Set off center in the disk is a flat, round can housing a black powder burster charge in an annular silk bag.

The eccentric position of the charge centers the ignition hole of the can directly under the fuze and places the main portion of the charge near to the point at which the two steel release wires are attached to the nosepiece.  This accounts for a more direct pull being exerted on the release wires when the burster charge detonates.

Operation: Upon release from the plane the aerial burst fuze functions.  The burster charge is fired. shearing the lead sealing strips and blowing off the forward nosepiece.  The nosepiece withdraws the release wires from the buckles of the retaining bands which frees the segments of the canister.  The 1-kilogram bombs separate and fall individually. 

1-kg Hollow Charge Bomb

 

  

Fuzes: B-5(b)

Overall Length: 17 and 1/2 inches

Length of body: 8 and 1/2 inches

Diameter of body: 1 and 3/4 inches

Thickness of wall: 1/16 inches

Material of wall: Steel

Type of suspension: Carried in clusters of 40 in a container
Suspension lug: None

Length of tail: 9 inches (w/ fuze)

Width of tail: 1 and 3/4 inches

Dimensions of tail struts:

-Length: 1 and 3/8 inches
-Diameter: 1 and 3/4 inches

-Thickness: 1/32 inch

Material of tail: Light Sheet Tin

Type of filling: Type 98 explosive and Tetryl booster
-TNT: 70%
-HND: 30%

Weight of filling: 11 ounces

Total weight of bomb: 2 pounds 3 ounces (excluding nosepiece)
Weight of tail assembly: 10 ounces

Charge/weight ratio: 31%

Color and markings: Body is a natural steel color.  The tail assembly is aluminum colored.
 

Construction of body: The body is constructed of tubular steel.  An aluminum nose cap and hollow metal cone are crimped into the nose.  The fuze and tail assembly are threaded into the base of the body.

Construction of tail: Four fins are soldered to the tail cone and braced at the after end by a circular strut.  The tail cone is secured to the fuze body by a four small screws.

The arming system consists of arming vanes at the after end of the tail connected to the inertia weight by a threaded reach rod which passes through the tail cone.  A spring-loaded safety detent which fits into the inertia weight is located on the side of the tail cone and is held in the safe position by an arming vane.

A thin metal disk attaching to the arming wire is placed on top of the arming vanes.  It prevents the vanes from rotating and acts as a drogue to withdraw the arming wire when the bomb is released.

Operation: When the bomb is released from the canister the pressure of the air on the drogue forces it from the bomb thereby withdrawing the arming wire.  The safety detent spring ejects the reach rod from the inertia weight.  The inertia weight and striker are then free to move forward on impact and hit the primer.

Type 2 No.6 Mk 21 Bomb Model 2

 
Fuzes: D-4(a)

Overall Length: 42 and 1/4 inches

Length of body: 39 inches

Diameter of body: 9 and 1/2 inches

Thickness of wall: 1/16 inches

Material of wall: Sheet Steel

Type of suspension: Horizontal
Suspension lug: Normal Navy suspension lug is held in place by a steel plate that fits over it and is riveted to the body section.

Length of tail: 3 and 1/4 inches

Width of tail: 11 inches
Width of tail fins: 2 and 1/8 inches
Length of tail fins: 8 inches

Dimensions of tail struts: None

Material of tail: 1/16-inch sheet steel

Type of filling: 36 1-kilogram high-explosive bombs

Weight of filling: 80 pounds

Total weight of bomb: 109 pounds

Charge/weight ratio: 72%

Color and markings: Gray overall with a green-tipped nose and a brown nose band.
 

Description: The hexagonally-shaped bomb container consists of a blunt-nose assembly and a light tailpiece around which are fitted three sheet steel sections held together by three metal retaining bands.  Two steel wires run longitudinally along the exterior of the container and pass through the three retaining band buckles.  One wire is attached to the nosepiece; the other is a safety wire which is removed after the container has been placed in the bomb rack.

The nose section is of two-piece construction.  The after piece is attached to the sheet steel sides by a welded stud for each section.  The forward piece is attached to the after one by three lead sealing strips.  The nosepiece, which has a fuze pocket to take the D-4(a) fuze, is filled by a wooden block.

A round metal can containing the burster charge in an annular silk bag is set off-center in the wooden block.  The initiating charge in the burster is directly beneath the fuze magazine.  The balance of the charge is off-center toward the point where the retaining band release wire is secured to the nosepiece.  The purpose of this offset is to exert a more direct pull on the release wire when the charge is detonated.

The tailpiece is held in place by a bungee cord fastened to a hook on the after end of each body section.  Two tail fins are riveted to the after portion of the sheet steel section to which the suspension lug is attached.  Two metal plates divide the container into three sections in each of which are packed 12 1-kilogram bombs.

Operation: After the bomb container is released from the plane, the aerial burst fuze functions.  The burster charge shears the lead sealing strips between the two sections of the nose, blowing the outer piece free from the container and withdrawing the release wire from the retaining band buckles.  The retaining bands open and the container sections separate allowing the 36 1-kilogram bombs to fall individually.

1-kg Antipersonnel bomb

  

Fuzes: B-5(c)

Overall Length: 11 and 3/8 inches

Length of body: 5 and 1/2 inches

Diameter of body: 2 and 3/8 inches

Thickness of wall: 1/32 inch

Material of wall: Steel
 

Type of suspension: Carried 36 in a container which is fuzed with a D-4(a) fuze

Suspension lug: None
 

Length of tail: 5 and 7/8 inches

Width of tail: 2 and 3/8 inches
Width of tail fins: approx. 1 inch at the widest point

Dimensions of tail struts:

-Diameter: 2 and 3/8 inches
-Length: 1 and 3/8 inches

Material of tail: Light tinned steel

Type of filling: Type 97 explosive
-TNT: 60%
-HND: 40%

Weight of filling: 1 pound 1 ounce

Total weight of bomb: 2 pounds 3 ounces

Charge/weight ratio: 50%
 

Color and markings: Bomb body may be a steel gray or black.  Tail assembly and fuze are aluminum colored.
 

Construction of body: The body is of one piece light steel construction.  It is cylindrical in shape, rounded at the nose and threaded in the base to receive the fuze assembly.  The inside of the body is coated with lacquer.
 

Construction of tail: The tail assembly is made of light tinned steel and is secured to the fuze body by four screws.  Four fins spaced 90 degrees apart are soldered to the tail cone and are braced by a ring strut at the after end.

An arming spindle extends from the fuze up through the tail cone, and has vanes attached at the end.  A drogue holds the vanes in a safe position.

Operation: When the bomb falls free from the container, the drogue retaining the vanes is carried away by the wind, allowing the vanes to rotate.  The motion of the vanes is transmitted through the reduction gear system to the spindle which is threaded out of the striker.  To prevent rotation of the striker, a key and keyway system is incorporated in the fuze body and striker.  As the spindle rises, it also lifts the gear frame to which is secured a pin retaining the safety detent.

The safety detent, which fits through the fuze body into the striker and holds it in position, is spring-loaded outward, and removal of the safety detent pin permits it to fly out.  With the spindle and detent removed, the heavy striker is held up only by a weak creep spring, which it overcomes on impact, initiating the gaine.

Type 3 No.6 Mk 23 Bomb Model 1

  

Fuzes: C-2(a)

Overall Length: 40 and 3/4 inches

Length of body: 21 and 3/4 inches

Diameter of body: 7 and 7/8 inches

Thickness of wall: 1/4 inch

Material of wall: Steel
 

Type of suspension: Horizontal

Suspension lug: Normal Navy type
 

Length of tail: 18 and 1/2 inches

Width of tail: 10 and 5/8 inches (excluding tail brake)
Width of tail fins: 4 and 3/4 inches
 

Dimensions of tail struts:

-Length: 7 and 7/8 inches
-Width: 1 and 3/8 inches

-Thickness: 3/32 inch

Material of tail: Sheet Steel 
  

Type of filling: Picric acid of Type 98 explosive
Weight of filling: 50 pounds
Total weight of bomb: 143 pounds
Charge/weight ratio: 35%
 

Color and markings: Gray overall with a green band around the nose.  New type markings may be found.
 

Construction of body: A cast-steel nose is attached by a continuous weld and 2 rows of 10 rivets each to a tubular-steel body.  An anti-penetration ring is welded to the exterior of the nose, 4 inches forward of the rivets.  This rind is 2 and 3/4 inches long and has an outer diameter of 7 and 7/8 inches.

A tail cone is held by 1 row of 24 rivets and a continuous weld to a collar which fits into the after end of the bomb body and is held there by 2 rows of screws (14 per row).
 

Construction of tail: Four fins are spot welded to the tail cone and braced by a single set of box-type struts.  A 1/16 inch sheet steel tail brake measuring 10 inches square is welded to the after end of the tail fins.

Type 3 No.6 Mk 27 Bomb (Rocket) Model 1
Please be sure to read the last paragraph in the description

 

Overall Length: 53 inches

Diameter of body: 7.8 inches
Weight of load: 5.5 pounds
Weight of propellant: 22 pounds
Total weight: 145.2 pounds
Maximum speed: 270m/sec

Color and markings: Gray overall with green and silver nose bands and red tail struts.

General description: This rocket, along with the Type 3 No.1 Mk 28 Model 1, were the only Japanese Navy rockets which were actually under production at the end of the war.  It is an aircraft-launched rocket intended for use against formations of large enemy planes, designed to eventually take the place of the Type 99 No.3 Mk 3 for air-to-air bombing.

The bomb consists of three sections: nose, barrel, and tail.  The nose section is conical in shape, with a fuze well in the nose and contains a burster charge, and a charge of incendiary shrapnel consisting of white phosphorous filled steel pellets.  It is threaded onto the barrel, and secured in place with screws.

The barrel is cylindrical in shape, closed at the forward end, and serves as the container and burning chamber for the rocket propellant.  It is fitted with one longitudinal launching rail.

The tail section is conical in shape, and is fitted with four fins of conventional Navy type.  It is threaed onto the barrel, and secured in place with screws.  The rear end is constricted to form a venturi for the escape of the driving gases.

The propellant is in grains 350 millimeters long and 19.2 millimeters in diameter, and is of the ballistite type, packed into the barrel.  It is ignited electrically.

The fuze used in this bomb is 10-second clockwork aerial burst fuze, using the standard Navy fuze clock, housed in a special brass case with a hand operated setting ring graduated in seconds from 0 to 10.

The data on this bomb is the result of incomplete investigation, and must not be considered as specific, accurate information.

Type 3 No.1 Mk 28 Bomb (Rocket) Model 1
Please be sure to read the last paragraph in the description
  

Fuze: Type 3 Mk 28

Overall Length (w/o fuze): 25 and 1/4 inches

Diameter of body: 4.69 inches
Weight of explosive: 1.32 pounds
Weight of propellant: 4.4 pounds
Total weight: 19.8 pounds

Color and markings: Gray overall with green and brown nose bands and red tail struts.

General description: In its early stages of development, this rocket was designated Mk 19.  It is constructed of a light aluminum alloy and carried a high-explosive charge.  It is intended for use against large aircraft.

 

Rocket power is supplied by 16 grains of ballistic type propellant 19.2mm x 350mm.  They are contained in the cylindrical barrel of the bomb, and are ignited electrically.

 

The nose section is ogival in shape, and carried the high-explosive charge.  A nose well is provided to take a special small impact fuze similar to the A-3(a).  The tail section is constricted to form a venturi, and is fitted with fins, riveted in place, for stabilization.  An error of 10 meters at a range of 500 meters is assumed by designers.   Two launching rails, 180 degrees opposed, are attached to the barrel of the bomb. 

 

The data on this bomb is the result of incomplete investigation, and must not be considered as specific, accurate information.



 Type 4 No.25 Mk 29 Bomb
 

 

Type 4 No.25 Mk 29 was in the process of being developed at the end of the war to take the place of the No.25 Mk 3 bombs as a weapon for use against large bomber formations.  It was designed either to be dropped in the same manner as the Mk 3 bombs, or to be detonated in the plane by the pilot.  The bomb incorporates a larger explosive charge, and smaller quantity of incendiary shrapnel, than do the Mk 3 bombs of the same size.

 

The nose section of the bomb is conical in shape, and is filled with a wooden block except for a central channel filled with explosive leading into the main charge of the bomb.  An adapter is supplied at the nose to receive the Type 3 electric gaine.

 

The barrel of the bomb is cylindrical in shape, and is filled with incendiary shrapnel of the white phosphorous filled steel pipe type.  A central burster charge of high explosive is surrounded by the incendiary shrapnel.

 

The conical tail section is filled with a central burster charge surrounded by the same type of incendiary shrapnel as is found in the barrel of the bomb.  An adapter is provided at the apex of the tail cone to receive the Type 99 Mk 3 tail fuze D-2(a), without centrifugal arming.  Tail fins are standard Navy design without rotational offset, such as is found in the Mk 3 bombs.

 

The bomb is fuzed in the nose with the Type 3 electric gaine fitted with a cable which leads into a firing switch in the cockpit of the airplane.  It is to be used when the pilot desires to fire the bomb in the airplane in a suicide attack on bomber formations.

 

The tail fuze is a Type 90 Mk 3 without centrifugal arming.  It is to be used when the bomb is dropped in an air-to-air bombing attack.

 

This bomb had not gone into production at the end of the war, but was considered by the Japanese to be a practical weapon for defense against heavy bombers.

 

The data on this bomb is the result of incomplete investigation, and must not be considered as specific, accurate information.

 

Next Time: Still more IJN bombs!

Imperial Japanese Navy Explosives - Bombs (Part 4)

 
 
 
Imperial Japanese Navy Explosives
 
 
 
 
 
 

Type 99 No.80 Mk 5 Bomb

  

 

Fuzes: Two B-2(b) tail fuzes

Overall Length: 95 and 1/2 inches

Length of body: 52 and 1/8 inches

Diameter of body: 16 and 1/8 inches

Thickness of wall:
-Nose: 4 inches
-Tail: 2 inches

Material of wall: Forged Steel
 

Type of suspension: Horizontal

Suspension lug: Two guide studs on the bomb bode, position a carrying band, to which a suspension lug is attached.
 

Length of tail: 43 and 3/8 inches

Width of tail: 22 and 1/8 inches

Width of tail fins: 11 and 1/16 inches
 

Dimensions of tail struts:

-Length: 15 and 1/4 inches

-Width: 2 and 3/4 inches

-Thickness: 3/16 inch

Material of tail: Sheet Steel
 

Type of filling: Type 91 explosive (trinitroanisol)

Weight of filling: 66 pounds (approximate)

Total weight of bomb: 1,641 pounds (w/o tail)

Charge/weight ratio: 4%
 

Color and markings: Gray overall.  Green band around the nose, white band aft of green band
 

Construction of body: The bomb body is constructed of one piece of forged machined steel.  There are eight recesses cut in the nose presumably to hold a windshield if the case is used as a projectile.  A male base plate which has two fuze pockets is screwed into the after end of the body.

The tail cone is formed of rolled sheet steel (3/32-inch) welded down one side.  Twelve screws fasten the unreinforced base of the cone to the base plate of the bomb which has holes drilled around the edge to receive the screws.  Three hinged doors in the cone permit access to the fuze pockets.

Two vane assembly supporting rings are located at the apex of the cone.  These rings are constructed to receive the B-2(b) vane assembly bushings which are held in place by set screws. Slots in the tail cone are located beneath the supporting rings to permit passage of the reach rods from the fuze bodies to the vane assembly.
 

Construction of tail: Four sheet-steel fins are spot welded to the tail cone and are braced by a single set of box-type tail struts.



 

Type 2 No.80 Mk 5 and No.150 Mk 5 Bombs
Please read the general description of this entry

No picture available
  
Type 2 No.80 Mk 5

Fuzes: Two B-2(b) tail fuzes
Gaines: Special Mk 5
Approximate weight of bomb: 1,760 pounds
Material of wall: Forget steel
Material of tail: Sheet Steel
Type of filling: Type 91 explosive
Approximate loading factor: 6%


No.150 Mk 5

Fuzes: Two large fuzes similar to the B-2(b) fuze
Gaines: Special Mk 5
Approximate weight of bomb: 3,300 pounds
Material of wall: Forget steel
Material of tail: Sheet Steel
Type of filling: Type 91 explosive
Approximate loading factor: 6%

 

Color and markings: Gray overall with a green and brown nose band and white tail struts
 

General Description: These two bombs were designed to fill the great need of the Japanese for armor-piercing bombs.  Prior to the design of these two, the Japanese Navy had only one true armor-piercing bomb, the Type 99 No. 80 Mk 5, an adaptation of a large caliber artillery shell produced by turning the shell down to a streamlined shape and adding a tail section and a slightly larger explosive charge.

Type 2 No.80 Mk 5 and No.150 Mk 5, although they were specifically designed as armor-piercing bombs, differ only slightly from the earlier bomb.  Type 2 No.80 Mk 5 differs from the Type 99 No.80 Mk 5 only in having a slightly larger explosive charge, and in having no recesses at the nose to hold a windshield in place.  No.150 Mk 5 is simply a larger version of the Type 2 No.80 Mk 5.

Both bombs of the No.80 size use two B-2(b) fuzes in the tail with the special Mk 5 gaine.  No.150 Mk5 has two large fuzes of similar construction to the B-2(b).  These bombs were never extensively produced and neither Type 2 No.80 Mk 5 or No.150 Mk 5 was ever found outside the Japanese homeland.

The data on these bombs is the result of incomplete investigation, and must not be considered as specific, accurate information.

Note: I'm not sure what the next few paragraphs were intended for, but they are included for accuracy towards the source material.

The Mk 7 bomb was never more than an idea as far as the Japanese Navy was concerned.  It was suggested and discussed by a meeting of designers in 1935, but no experiments were carried out because the idea was considered impractical and unnecessary.  The bomb, as planned, was to consist of the 1 kilogram practice bomb, with a conical glass bottle of bacillus culture in place of the smoke mixture in the tail.

A lengthened striker was to break the bottle, and the culture was to spread by the force of impact.  A spread of 1 meter in diameter was hoped for.  No specific type of bacillus had been selected for the bomb.  Distinctive color marking for the bomb was to have been purple painted nose and tail.

Type 5 No.1 Mk 9 Model 1 and Type 3 No.6 Mk 9 Bombs

No picture available
  
Type 5 No.1 Mk 9 Model 1

Overall length: 35.4 inches

Diameter of body: 3.93 inches

Weight of explosive: 2.2 pounds

Weight of propellant: 4.4 pounds

Total weight of bomb: 33 pounds

Maximum speed: 230m/sec

  
Type 3 No.6 Mk 9
Overall length: 66.9 inches

Diameter of body: 7.87 inches

Weight of explosive: 22 pounds

Weight of propellant: 22 pounds

Total weight of bomb: 184.8 pounds

Maximum speed: 230m/sec
 

Color and markings: Gray overall. Green band on nose, with brown band just aft of green band.  Gray tail struts.
  

General description: Neither of these rockets had been put into production at the end of the war, although experiments had been finished on both of them.  Both were designed as aircraft launched weapons for use against surface targets; Type 5 No.1 Mk 9 Model 1 against surface submarines, and the Type 3 No.6 Mk 9 against landing craft and small ships.

These rockets are similar to the Mk 27 and Mk 28 rockets of comparable sizes, but both are somewhat heavier.  Both carry high-explosive loads, and the Type 5 No.1 Mk 9 Model 1 has a semi-armor piercing nose.
 
Exact fuzing is unknown, but it is known that the Type 5 No.1 Mk 9 Model 1 uses a fuze with a 0-2 second delay.  The Type 3 No.6 Mk 9 is assumed to use an instantaneous fuze.  Both of these rockets are fin stabilized, and more closely resemble American aircraft launched rockets than any of the other Japanese rockets.  However, their small propellant charges result in such low speed that their performance in no way compares with that of American rockets.

Type 98 No.7 Mk 6 Bomb Model 1
  

  

Fuzes: (w/ Magazine) A-3(a), or A-3(b)

Overall Length: 40 inches

Length of body: 21 and 3/4 inches

Diameter of body: 7 and 7/8 inches

Thickness of wall: 1/4 inch

Material of wall: Steel
 

Type of suspension: Horizontal

Suspension lug: Normal Navy suspension lug
 

Length of tail: 18 and 3/16 inches

Width of tail: 10 and 5/8 inches

 

Dimensions of tail struts:

-Length: 7 and 7/8 inches
-Width: 1 and 3/8 inches 

-Thickness: 3/32 inch

Material of tail: Sheet Steel
 

Type of filling: Four thermite-filled electron fire pots are contained within the bomb.  The nose and tail fire pots are cylindrical, while the two in the body are semicircular.  A central channel filled with quick-match runs the length of the bomb.  A black-powder charge is located int he circular recess in the nose piece.
 

Weight of filling: 81 pounds

Total weight of bomb: 156 pounds

Charge/weight ratio: 51%

 

Color and markings: Gray overall with a red nose band and red tail struts.  New type color markings will be found.
 

Construction of body: A cast-steel nose piece is riveted with 2 rows of 10 rivets each to a tubular steel body.  The tail cone is held by 1 row of 24 rivets to a collar which is held in the base of the bomb by 2 rows of screws (14 per row).
 

Construction of tail: Four steel fins are welded to the tail cone and are braced by a single set of box-type struts.

Operation: On impact, the magazine in the nose fuze fires the black powder and the igniting charge.  The black powder ejects the fire pots from the bomb case.  The igniting charge ignites the quick-match which initiates combustion of the thermite.

Type 98 No.7 Mk 6 Bomb Model 2

Fuzes: (w/ Magazine) A-3(a), or A-3(b)

Overall Length: 42 inches

Length of body: 21 inches

Diameter of body: 9 and 3/8 inches

Thickness of wall: 3/16 inch

Material of wall: Steel
 

Type of suspension: Horizontal

Suspension lug: Normal Navy suspension lug
 

Length of tail: 21 inches

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

 

Dimensions of tail struts:

-Length: 9 and 1/2 inches
-Width: 1 and 3/8 inches 

-Thickness: 1/16 inch

Material of tail: Sheet Steel
 

Type of filling: A central thermite core surrounded by solidified kerosene, petrol, and alcohol-soap mixture.

Weight of filling:
-20 pounds of inflammable mixture
-7.5 pounds of thermite

Total weight of bomb: 145 pounds
Charge/weight ratio: 22%

   

Color and markings: Gray overall with two longitudinal diametrically opposite thin red lines.  Red nose and red struts.  New type markings will be found.
 

Construction of body:  cast-steel nose is attached to a tubular-steel body by a continuous circumferential weld and 2 rows of 16 plug welds each.  A wood block and black powder burster charge are located in the nose.  Housed within the body is a steel cylinder which contains the incendiary filling. 
 
A central copper tube within the cylinder contains quick-match.  A tail cone is attached to a collar by a continuous circumferential weld and 16 plug welds.  The collar fits into the after end of the body and is held there by 2 rows of 16 screws each.
 

Construction of tail: Four steel fins are welded to metal strips which are riveted (14 rivets each) to the tail cone.  The fins are braced by a single-set of box-type struts.

Operation: On impact, the magazine in the nose fuze fires the black-powder charge which shears off the tail cone and ejects the incendiary cylinder out of the bomb case.  At the same time, the quick match is ignited.  This in turn sets fire to the thermite and the inflammable mixture.

Type 1 No.7 Mk 6 Bomb Model 3 Modification 1
 

Fuzes: A-3(a)

Overall Length: 42 and 1/4 inches

Length of body: 21 inches

Diameter of body: 9 and 3/8 inches

Thickness of wall: 1/8 inch

Material of wall: Steel

Type of suspension: Horizontal

Suspension lug: Normal Navy suspension lug

Length of tail: 21 inches

Width of tail: 13 and 1/4 inches

Width of tail fins: 6 inches

Dimensions of tail struts:
-Length: 9 and 1/2 inches

-Width: 1 and 3/8 inches
-Thickness: 1/16 inch

Material of tail: Sheet Steel
  

Type of filling: 182 cylindrical incendiary pellets are arranged around a central cardboard tube.  The pellets are bound together with string to form rings.  The rings surround the central tube which is filled with gray powder.  All the space in the bomb not occupied by the pellets is filled with this powder.

Weight of individual pellets: 7 ounces
Total weight of pellets: 81 pounds
Length of pellets: 2 and 1/8 inches
Diameter of pellets: 1 and 1/2 inches

Composition of pellets:
-Barium nitrate: 35%
-Ferric oxide: 28%
-Aluminum: 18%
The remainder is synthetic rubber of polysulphite type resembling "Thiokol."

Weight of igniter powder: 30 pounds

Composition of igniter powder:
-Barium nitrate: 75%
-Aluminum: 24.5%
-Oil: 0.3%
-Moisture: 0.2%

Weight of filling: 111 pounds

Total weight of bomb: 160 pounds

Charge/weight ratio: 69.4%

Color and markings: Gray overall with a 3 and 1/2-inch red band at the nose and red tail struts.  New type markings will be found.

Construction of body: A cast-steel nosepiece is attached to a longitudinally welded steel body by a continuous circumferential weld.  The nose contains a wooden block 1 and 3/4 inches thick to which a light metal gaine well is secured by three nails.

A longitudinally welded tail cone is welded to a collar which fits into the after end of the body and is held there by a single row of 16 screws.

Construction of tail: our steel fins are spot welded to the tail cone.  They are braced by a single set of box-type struts.

Remarks:
-Type 1 No.7 Mk 6 Model 3: This bomb uses the same case as that described above but differs in the filling.  It contains a high-explosive burster charge in a central tube and an explosive filling of approximately 520 wedge-shaped rubber pellets impregnated with iron and aluminum.



 

Type 3 No.25 Mk 8 Bomb Model 1
  

 

Fuzes: A-3(a)

Overall Length: 67 inches

Length of body: 39 and 5/8 inches

Diameter of body: 12 inches

Thickness of wall: 1/2 inch

Material of wall: Steel

Type of suspension: Horizontal

Suspension lug: Normal Navy suspension lug

Length of tail: 27 and 3/8 inches

Width of tail: 19 and 5/8 inches

Width of tail fins: 6 and 3/8 inches

Dimensions of tail struts: None

Material of tail: Sheet Steel

  

Type of filling: Type 97 explosive

Weight of filling: 263 pounds

Total weight of bomb: 649 pounds

Charge/weight ratio: 40%

 

 Color and markings: Green band around the nose, brown band aft of green band.  Gray body and tail.

Construction of body: A cast-steel nose is attached to a tubular-steel body by a continuous circumferential weld and 12 plug welds.  A tail cone is held to a collar by 8 plug welds.  The collars fits into the after end of the body and is held there by 40 screws.

Construction of tail: The normal tail cone has been cut off 8 and 3/4 inches aft of the junction with the bomb body proper and to this has been welded a 3/16 inch steel cylinder and four 1/8 inch steel hollow tail fins.

Tail cylinder:
-Outside diameter: 5 and 5/8 inches
-Length: 18 and 5/8 inches
-Type of filling: Type 97 explosive
 
Tail fins:
-Shape of cross-section: Triangular
-Overall length: 25 and 1/2 inches
-Height: 6 and 3/8 inches
-Width at base: 2 and 1/2 inches

Reinforcement of fins:

1. A box strut made of 1/8-inch mild steel runs the length of the fin on the inside.  The box strut is 7/8-inch wide at the top and 1 and 3/4 inches high and 22 inches long.  The strut is welded along the two lower edges to the side of the fins proper and spot welded along the sides.

2. Three 1/4-inch mild steel braces, 1 and 1/2 inches wide at the top, 2 and 1/2 inches wide at the bottom and 2 inches high are welded at 5 and 1/2-inch intervals to the box strut and the sides of the fins.  The lower sides of these braces have been shaped to fit the cylinder.

3. The end of the fins is closed by a 1/8-inch steel plate welded in place.


 
 

Next Time: More IJN bombs, including cluster munitions

Imperial Japanese Navy Explosives - Bombs (Part 3)

 
 
 
Imperial Japanese Navy Explosives
 
 
 
 
 
 

Type 99 No.6 Mk 2 Bomb Modification 1

  

 

Fuzes: A-3(a)

Overall Length: 42 inches

Length of body: 21 inches

Diameter of body: 9 and 3/8 inches

Thickness of wall: 3/16 inch

Material of wall: Steel
 

Type of suspension: Horizontal

Suspension lug: Normal Navy type suspension lug
 

Length of tail: 21 inches

Width of tail: 13 and 1/4 inches

Width of tail fins: 6 inches
 

Dimensions of tail struts:
Outer Struts

-Length: 9 and 1/2 inches

-Width: 1 and 3/8 inches

-Thickness: 1/16 inch

Inner Struts

-Length: 4 and 3/4 inches

-Width: 1 and 3/8 inches

-Thickness: 1/16 inch

Material of tail: Sheet Steel
 

Type of filling: Type 98 explosive

Weight of filling: 85 pounds (approximate)

Total weight of bomb: 140 pounds

Charge/weight ratio: 60%
 

Color and markings: Gray overall with a green-tipped nose and a blue band just aft of the green.
 

Construction of body: A cast-steel nose is attached to a tubular-steel body by a continuous circumferential weld and 2 rows of 16 plug welds.  An anti-ricochet nose attachment consisting of a cylindrical metal ring 1/8-inch thick bent at a 90 degree angle is spot welded to the bomb at a point 1 and 1/2 inches forward of the junction of the nose and body.

The ring is 9 and 3/8 inches in diameter and 3 and 3/4 inches long.  There are two notches 7/8-inch wide and 2 and 1/4 inches deep cut into the forward edge of the ring 180 degrees apart and in line with the suspension lug.

The tail cone is attached to a collar by a continuous circumferential weld and 16 plug welds held there by 2 rows of 16 screws.
 

Construction of tail: Four tail fins are welded to the tail cone and are braced by four sets of box-type tail struts.



 

Type 1 No.25 Mk 2 Bomb Model 1

 

Fuzes: A-3(a), B-3(a)

Overall Length: 72 inches

Length of body: 35 and 1/2 inches

Diameter of body: 13 and 3/4 inches

Thickness of wall: 1/4 inch

Material of wall: Steel
 

Type of suspension: Horizontal

Suspension lug: Normal Navy type suspension lug
 

Length of tail:
-First section: 21 and 1/2 inches
-Extension: 15 inches

Width of tail: 14 inches

Width of tail fins: 5 and 1/4 inches
 

Dimensions of tail struts:
Forward Struts

-Length: 5 and 1/4 inches

-Width: 2 inches

-Thickness: 1/8 inch

After Struts

-Length: 5 inches

-Width: 1 and 1/8 inches

-Thickness: 1/16 inch

Material of tail:
-First section: Sheet Steel
-Extension: Plywood

Type of filling: Type 98 explosive

Weight of filling: 317 pounds

Total weight of bomb: 572 pounds

Charge/weight ratio: 56%
 

Color and markings: Gray overall with a green band forward of a blue band on the nose.
 

Construction of body: A cast-steel nose is attached by a continuous circumferential weld and 16 plug welds to a longitudinally welded tubular steel body.  A tail cone is attached to a collar by 36 screws.  The collar is held in the base of the bomb body by a single row of 16 plug welds.
 

Construction of tail: The tail is constructed in two sections, the first section has eight 1/8-inch sheet steel fins welded to the tail cone and supported by seven steel struts.  The second section consists of eight plywood fins in steel frames supported at their inner edges by a metal cylinder 4 inches in diameter and on their outer edges by seven steel struts.  The second section is attached to the first by bolted steel plates on each of the eight fins. 

Apparently the wooden tail section is designed to come off on water impact.

 

Type 1 No.25 Mk 2 Bomb Model 1 Modification 1

 

Fuzes: A-3(a), B-3(a)

Overall Length: 72 inches

Length of body: 35 and 1/2 inches

Diameter of body: 13 and 3/4 inches

Thickness of wall: 1/4 inch

Material of wall: Steel
 

Type of suspension: Horizontal

Suspension lug: Normal Navy type suspension lug
 

Length of tail:
-First Section: 21 and 1/2 inches
-Extension: 15 inches

Width of tail: 14 inches

Width of tail fins: 5 and 1/4 inches
 

Dimensions of tail struts:
Forward Struts

-Length: 5 and 1/4 inches

-Width: 2 inches

-Thickness: 1/8 inch

After Struts

-Length: 5 inches

-Width: 1 and 1/8 inches

-Thickness: 1/16 inch
 

Material of tail:
-First Section: Sheet Steel
-Extension: Plywood
 

Type of filling: Type 98 explosive 

Weight of filling: 317 pounds

Total weight of bomb: 585 pounds

Charge/weight ratio: 54%
 

Color and markings: Gray overall with a green band forward of a blue band on the nose.
  

Construction of body: A cast-steel nose is attached by a continuous circumferential weld and 16 plug welds to a longitudinally welded tubular steel body.

An anti-ricochet attachment consisting of a metal ring and two supporting plates is welded to the bomb at a point 1 and 3/4 inches forward of the junction of the nose and body.  The ring has a 13 and 3/4 inch diameter, is 5 inches long and 5/32-inch thick. 
 
The two semicircular supporting plates are welded to the interior of the forward end of the ring and to the nose of the bomb.  There are two notches cut into the forward edge of the ring 180 degrees apart.  One notch is in line with the suspension lug.  The supporting plates fail to meet by 7/8-inch at the two notches.

A tail cone is attached to a collar by 36 screws.  The collar is held in the base of the bomb body by a single row of 16 plug welds.
  

Construction of tail: The tail is constructed in two sections: the first section has eight 1/8-inch sheet steel fins welded to the tail cone and supported by seven steel struts.  The second section consists of eight plywood fins in steel frames supported at their inner edges by a metal cylinder 4 inches in diameter and on their outer edges by seven steel struts.  The second section is attached to the first by bolted steel plates on each of the eight fins. 

 

Apparently the wooden tail section is designed to come off on water impact.

 

Type 99 No.3 Mk 3 Bomb
  

  

Fuzes:
-Nose: A-1(b), A-3(c)
-Tail: Solid plug or D-2(a), D-2(b), or D-2(c) 

Overall Length: 24 and 1/2 inches

Length of body: 13 and 1/2 inches

Diameter of body: 5 and 3/4 inches

Thickness of wall: 3/16 inch

Material of wall: Steel
 

Type of suspension: Horizontal

Suspension lug: Two normal Navy suspension lugs diametrically opposed
 

Length of tail: 11 inches

Width of tail: 6 and 1/8 inches

Width of tail fins: 1 and 11/16 inches
 

Dimensions of tail struts:

-Length: 4 and 1/8 inches

-Circumference: 3/16 inch

Material of tail: Sheet Steel
 

Type of filling: Canister containing 168 phosphorus-filled steel pellets.  Picric acid in tail cone and central burster charge.
 

Weight of filling: Picric Acid - 3.5 pounds

Total weight of bomb: 70 pounds

Color and markings: Gray body and tail.  A 2-inch silver band around the nose, a 1-inch silver band on the end of the tail fins, and two red lines diametrically opposite run from nose to tail.  New markings will be found.
 

Construction of body: A cast-steel nose piece is circumferentially welded to a longitudinally welded steel body.  A canister containing the incendiary pellets is fitted inside the body.  A steel tube containing the central burster charge is screwed into the nose and extends the length of the body. 

A tail cone is circumferentially welded to a collar which threads into the after end of the body.  The tail cone is filled with picric acid.  A steel plate separates the explosive from the incendiary filler.
 

Construction of tail: Four steel fins are spot welded to the tail cone.  They are braced by a single set of 3/16-inch round struts flattened at each end and riveted to the fins.

To impart the rotary motion necessary to arm the D-2 fuzes, the ends of the tail are bent at an angle of approximately 19 degrees.

Remarks: A factory variation of the incendiary filling consists of 21 lengths of mild steel pipe, 1-inch in diameter, packed vertically in the canister.  Each length is divided into 8 equal sections by being cut completely through except for 1/4 inch of circumference left along 1 side.  The bomb contained 168 phosphorus-filled pellets.

Modification 1: A variation of this bomb listed as Modification 1 has four fins welded to the body and utilizes the new color markings.  The fins, which are 6 inches long, 1 and 1/2 inches wide, and 1/16-inch thick, are welded tot he body at 4 and 5/8 inch intervals, two between each suspension lug. 

They are offset 35 degrees from the longitudinal axis of the bomb and serve to accelerate its clockwise rotation.  The bomb is painted gray.  It has a silver nose tipped with green.  The tail struts are red.

Type 3 No.6 Mk 3 Bomb Model 1

Fuzes: D-2 series

Overall Length: 40 inches

Length of body: 23 inches

Diameter of body: 7 and 7/8 inches

Thickness of wall: 1/8 inch

Material of wall: Steel
 

Type of suspension: Horizontal

Suspension lug: Normal Navy suspension lug
 

Length of tail: 17 inches

Width of tail: 7 and 7/8 inches

Width of tail fins: 2 and 1/2 inches

Dimensions of tail struts:

-Length: 5 inches

-Width: 1 and 1/2 inches

-Thickness: 1/8 inch

Material of tail: Steel
 

Type of filling: Three cylindrical steel canisters each containing 87 white phosphorus filled cylindrical steel pellets.  Each canister has a central exploder tube filled with Type 98 explosive.  A heavy wax coating covers each canister.

Dimensions of filling:
-Length of canister: 4 and 3/8 inches
-Diameter of canister: 7 and 1/4 inches
-Length of pellet: 1 and 1/4 inches
-Diameter of pellet: 1 and 1/8 inches
-Diameter of exploder tube: 1 and 7/16 inches
-Weight of individual canister: 24 pounds
  

Weight of filling: 3 canisters, 72 pounds; tail cone charge - 11.2 pounds

Total weight of bomb: 118 pounds

Charge/weight ratio: 71%
 

Color and markings: Silver nose tipped with a green band.  Body is gray overall, except for red tail struts.  Marked "Provisional designation Type 3 No.6 Mk 3 Model 1".
 

Construction of body: The bomb consists of a nosepiece, body, and tail assembly.  The conical-shaped nosepiece is welded to the body and has a steel plate welded where the fuze pocket would be.  The cavity in the nosepiece is filled with a wooden block.  The body is cylindrical in shape and is welded longitudinally. 

The tail cone is welded to a coupling ring which fits into the body and is held there by a single row of screws. A burster charge of cast Type 98 explosive is contained in the tail cone.  A perforated steel plate separates the explosive from the incendiary filling.
 

Construction of tail: The tail cone is welded longitudinally.  Four angled fins are welded to the cone and braced by a single set of box-type struts.  The angle of these fins imparts a counter-clockwise rotation in flight to the bomb, thereby arming the clockwork fuze.

Operation: Upon release from the plane the aerial burst fuze functions initiating the tail cone charge which detonates the central burster tube.  The bomb case and canisters are ruptured, scattering the incendiary pellets.  The white phosphorus is ignited when it is exposed to the air.

Type 2 No.25 Mk 3 Bomb Model 1
 

Fuzes:
-Nose: A-3(a)
-Tail: D-2(a)

Overall Length: 71 inches

Length of body: 40 inches

Diameter of body: 12 inches

Thickness of wall: 1/4 inch

Material of wall: Steel

Type of suspension: Horizontal

Suspension lug: Normal Navy suspension lug

Length of tail: 31 inches

Width of tail: 12 inches

Width of tail fins: 5 and 1/4 inches

Dimensions of tail struts:

-Width: 2 inches

Material of tail: Sheet Steel
  

Type of filling:
-Incendiary filling: 750 (approx.) steel cylinders containing an incendiary mixture
-Barium nitrate: 35.8%
-Iron oxide: 27.2%
-Aluminum powder: 13.6%
-Magnesium shavings: 10.3%
-Synthetic shavings: 13.1%

Dimensions of cylinders:
-Length: 2 and 3/4 inches
-Width: 1 and 1/16 inches
-Thickness: 1/8 inch

Packing of cylinders: The cylinders are packed in circular rows in nine perforated nitrocellulose containers.

Burster charges: Two burster charges are contained in the nose piece and in the tail cone.  The explosive is also scattered throughout the interstices of each incendiary section.

The composition of the charge is as follows:
-Barium nitrate: 75.2%
-Aluminum powder: 24.2%
-Oil: 2%

Note: Perforated steel plates in the nose and tail separate the burster charges and the incendiary filling.

Weight of filling:
-Burster charges: 73 pounds
-Incendiary filling: 300 pounds
Total weight of bomb: 550 pounds

Color and markings: Gray overall.  Silver nose tipped with green.  Red tail struts.

Construction of body: A cast-steel nose is welded to a tubular-steel body by a continuous weld and a row of 12 plug welds.  The tail cone is held by 1 row of 18 plug welds and a continuous weld to a collar which is held in the base of the bomb by 2 rows of round-headed screws, 20 in each row.

Construction of tail: Four steel fins are welded at an angle to the tail cone.  The fins are braced at the juncture with the tail cone by a steel strip welded to the underside of the bent fin and the cone.

At the after end, the fins are braced by two sets of box-type struts.  The angle of the fins imparts a counter-clockwise rotation in flight to the bomb.

Operation: The aerial burst fuze functions at a preset height.  The detonation of the burster charges ignites the inflammable trays and the incendiary cylinders and ruptures the bomb case.  The fragments are scattered over a 175 yard radius when air-burst occurs 100 feet above ground.



 

Type 3 No.25 Mk 4 Bomb Modification 1
Please make sure to read the remarks section of this entry
 

 

Overall Length: 1.9 meters

Weight of explosive: 3.5 kilograms
Diameter: 0.3 meters
Weight of propellant: 15.0 kilograms
Maximum speed: 100m/sec
Total weight: 315 kilograms

General description: Design work on this bomb was originally started in 1935, and produced the Basic 3 No.25 Mk 4 bomb, which was used for all early Japanese Navy rocket testing and research.  Production commenced on the Type 3 bomb in 1943, and a reasonable number of the bombs had been produced or were in the process of production at the end of the war.

This bomb is an example of the early ideas on the use of rocket power.  It is essentially an armor-piercing bomb, designed to utilize rocket power to increase penetration.  However, as finally produced, the bomb had a maximum velocity of only 100 meters per second, and consequently was of little value.

The bomb consists of an armor-piercing explosive nose section, a rocket motor tail section, and a cylindrical center section joining the two, and carrying the fuzes for both sections.  The armor piercing nose is of extremely heavy construction, and is fuzed in the base with a fuze incorporating a short delay.  A very small explosive charge, approximately 3.5 kilograms in weight, is used as a burster.  Type 91 explosive is used, as in all other Japanese Navy armor piercing ammunition. 

The rocket motor tail section constituted about half of the overall length of the bomb, and carried 15 kilograms of propellant of the ballistite type.  It is fuzed at its forward end for ignition of the propellant, with a fuze which operates after the bomb leaves the plane.  The tail section is equipped with standard fins for stabilization of the bomb in flight.

The cylindrical center section of the bomb has the function of joining the nose and tail sections and of carrying the fuzes for both.  Both fuzes, with arming vane extensions which project out of the side of the bomb.  Two hinged doors in the side of the bomb allow access to the fuzes.

Remark: The data on this bomb are the result of incomplete investigation, and must not be considered as specific, accurate information.
 

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