Monday 29 February 2016

Imperial Japanese Navy Explosives - Bombs (Part 1)

 
 
 
 
Imperial Japanese Navy Explosives
 
 
 
 
 
Type 97 No.6 Land Bomb
 
  
Fuzes: A-3(a)
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 type
 
Length of tail: 18 and 3/16 inches
Width of tail: 10 and 5/8 inches
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 or Type 98 explosive
Weight of filling: 50 pounds
Total weight of bomb: 124 pounds
Charge/weight ratio: 40%
 
Color and markings: Gray overall with a green band on the nose, green tail struts, and a blue band around the body.  Two thin red lines 180 degrees apart run longitudinally along the bomb.  New type markings will 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.  A circumferential weld to a collar which fits into the after end of the body 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.
 
 
 
 
  
 
Type 2 No.6 Land Bomb Model 5
 
  
Fuzes: A-3(a), A-3(b)
Overall Length: 42 inches
Length of body: 25 and 3/4 inches
Diameter of body: 10 inches
Thickness of wall: 1/16 inch
Material of wall: Sheet steel
  
Type of suspension: Horizontal
Suspension lug: Standard Navy type suspension lug
  
Length of tail: 16 and 1/4 inches
Width of tail: 10 inches
Width of tail fins: 4 and 1/4 inches
  
Dimensions of tail struts:
-Length: 10 inches
-Width: 1 inche
-Thickness: 1/16 inch
Material of tail: Sheet Steel
  
Type of filling: Five 7kg high-explosive bombs and a high-explosive central burster
Total weight of bomb: 132 pounds (approx.)
  
Color and markings: Gray overall with a brown nose section.  New type color markings will be found.
  
Construction of body: A hollow-steel nosepiece and a hollow tail cone are connected by an explosive-filled central tube on the inside and two half cylinders of sheet steel on the outside.  The two half cylinders are connected by four metal tabs riveted to each half of the cylinder on the inside. 
 
There are four notches 3/16 inch square and 90 degrees apart in each end of the assembled cylinder.  The notches fit around the four pins which are on the nosepiece and tailpiece.  There is a spacer plate and five space strips attached to the central tube.
 
Construction of tail: Four steel fins are welded to the tail cone and are braced by a single circular strut at the after end.  The fins are set at an angle to the tail cone in such a manner that they will impart a rotary motion to the container when it is dropped. 
 
Description of 7kg high-explosive bomb: No fuze or complete bomb has been found.  The only information available on the bomb and fuze comes from a captured Japanese bomb chart.  The bombs are alleged to be nose fuzed, 20 and 1/4 inches long and 3 and 1/2 inches in diameter.
 
The tail fins from several of the bombs have been found.  The tail fins are painted gray, one has a 4 and 1/4 inch slot which allows the narrower one to fit into it.  The fins are spot-welded at the extreme ends of the slot.  The tail fins are braced by box-type struts welded to the after-most end.
 
Dimensions of "Wide" tail fins:
-Width: 4 and 1/4 inches
-Length (Approx.): 10 and 3/8 inches
-Thickness: 1/16 inch
 
Dimensions of "Narrow" tail fins:
-Width: 3 and 1/2 inches
-Length (Approx.): 10 and 3/8 inches
-Thickness: 1/16 inch
Dimensions of tail struts:
-Width: 15/32 inch
-Length (Approx.): 2 and 3/8 inches
-Thickness: 1/16 inch
 
Remarks: Production of this bomb ceased before the end of the war
 
 
No.25 Land Bomb

 
Fuzes: A-3(a), A-3(b), C-2(a), B-3(a), C-1(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 suspension lug
 
Length of tail: 36 and 1/2 inches
Width of tail: 19 and 3/16 inches
Width of tail fins: 7 and 5/8 inches
 
Dimensions of tail struts:
-Length: 13 and 7/8 inches
-Width: 2 and 1/4 inches
-Thickness: 3/32 inch
 
Material of tail: Sheet Steel
Type of filling: Type 98 explosive
Weight of filling: 330 pounds
Total weight of bomb: 550 pounds
Charge/weight ratio: 60%
 
Color and markings: Gray overall with a green nose band and green tail struts.  There are two thin, red lines 180 degrees apart along the length of the bomb.  New type color markings will be found.
 
Construction of body: A cast-steel nose is welded to a tubular-steel body by a continuous weld and a row of 16 plug welds.  The tail cone is held by 1 row of 32 screws to a collar which is held in the base of the bomb by a row of 16 plug welds.  There is a threaded fuze pocket in both the nose and tail.
 
Construction of tail: Four fins are spot-welded to the tail cone and braced by a single set of box-type struts.


 
 
 
Type 98 No.25 Land Bomb

 
Fuzes: A-3(a), A-3(b), C-2(a), B-3(a), C-1(a)
Overall Length: 72 inches
Length of body: 39 and 1/2 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: 32 and 1/2 inches
Width of tail: 16 and 5/8 inches
Width of tail fins: 7 and 5/16 inches
 
Dimensions of tail struts:
-Length: 13 and 7/8 inches
-Width: 2 and 1/4 inches
-Thickness: 3/32 inch
Material of tail: Sheet Steel
 
Type of filling: Picric acid or Type 98 explosive
Weight of filling: 211 pounds
Total weight of bomb: 532 pounds
Charge/weight ratio: 40%
 
Color and markings: Gray overall with a green nose band and green tail struts. There are two thin, red lines 180 degrees apart along the length of the bomb. New type color markings will be found.
  
Construction of body: A cast-steel nose is welded to a tubular-steel body by a continuous weld and 1 row of 12 large 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 40 screws in 2 rows of 20 each.  There is a threaded fuze pocket in both the nose and tail.
  
Construction of tail: Four fins are spot-welded to the tail cone and braced by a single set of box-type struts.
Remarks: The Type 98 bomb is reported in some instances to be turned down to appear smooth on the exterior surface.



 
  
No.80 Land Bomb
 
  
Fuzes: A-1(c), B-3(b), A-3(d)
Overall Length: 113 inches
Length of body: 72 inches
Diameter of body: 18 inches
Thickness of wall: 1/2 inch
Material of wall: Steel
 
Type of suspension: Horizontal
Suspension lug: Two guide studs on the bomb body position a carrying band to which a suspension lug is attached.
 
Length of tail: 41 inches
Width of tail: 25 inches
Width of tail fins: 10 and 1/2 inches
 
Dimensions of tail struts:
-Length: 17 and 1/4 inches
-Width: 3 and 5/8 inches
-Thickness: 1/8 inch
Material of tail: Steel
 
Type of filling: Picric acid (tail cone is filled), or Type 98 explosive
Weight of filling: 842 pounds
Total weight of bomb: 1,760 pounds
Charge/weight ratio: 48%
 
Color and markings: Grey overall.  Green nose and tail struts.  Two red lines 180 degrees apart along the longitudinal axis of the bomb.  Blue band around the body.  New type markings will be found.
 
Construction of body: A cast-steel nose is attached to a tubular body by a continuous circumferential weld and 3 rows of 14 rivets each.  The tail cone is held by a continuous circumferential weld and 2 rows of 16 rivets each to a collar which is held in the base of the bomb by 2 rows of round-headed screws (32 screws in each row).  This bomb has a threaded fuze pocket in both the nose and tail.
 
Construction of tail: Four 1/8 inch steel fins are spot welded to the tail cone and are braced by a single set of box-type struts.



 
Type 99 No.6 Ordinary Bomb
  

 
Fuzes: A-3(a), A-3(b)
Overall Length: 42 and 1/4 inches
Length of body: 25 and 1/2 inches
Diameter of body: 8 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: 16 and 7/8 inches
Width of tail: 12 and 1/4 inches
Width of tail fins: 5 and 5/8 inches
 
Dimensions of tail struts:
-Length: 9 inches
-Width: 1 inch
-Thickness: 1/16 inch
Material of tail: Steel
 
Type of filling: Picric acid or Type 98 explosive
Weight of filling: 70 pounds
Total weight of bomb: 138 pounds
Charge/weight ratio: 50%
 
Color and markings: Gray overall with a green nose band and green tail struts.  There are two thin red lines 180 degrees apart along the length of the bomb.  New type color markings will be found.
 
Construction of body: The body is constructed of 1 piece of machined forged steel.  It is threaded in the nose to receive a fuze.  The after end of the body is threaded internally to accommodate a male base plate.  A tail cone is secured to the base plate by a signle row of 20 screws.  There is no explosive in the tail cone.
 
Construction of tail: Four fins are spot welded to the tail cone and braced by a single set of box-type struts.

  

 
Type 99 No.25 Ordinary Bomb Model 1
  
 
Fuzes: A-3(a), A-3(b), B-2(a)
Overall Length: 68 inches
Length of body: 39 and 3/4 inches
Diameter of body: 11 and 1/2 inches
Thickness of wall: 1/4 inch
Material of wall: Steel
 
Type of suspension: Horizontal
Suspension lug: Normal Navy suspension lug
 
Length of tail: 28 inches
Width of tail: 16 and 1/4 inches
Width of tail fins: 6 and 15/16 inches
 
Dimensions of tail struts:
-Length: 12 inches
-Width: 1 and 5/8 inches
-Thickness: 1/16 inch
Material of tail: Steel
 
Type of filling: Type 91 (Trinitroanisol)
Weight of filling: 132 pounds
Total weight of bomb: 550 pounds
Charge/weight ratio: 24%
 
Color and markings: Gray overall with a green nose band and green tail struts.  There are two thin red lines 180 degrees apart along the length of the bomb.  New type color markings will be found.
 
Construction of body: The body is constructed of one piece of machined forged steel.  It is threaded in the nose to receive a fuze.  The after end of the body is threaded internally to accommodate a male base plate.  The base plate is drilled centrally to receive the tail fuze.  A tail cone is secured to the base plate by six screws.  The cone is empty and has three hinged doors to permit access to the tail fuze pocket in the base plate.
 
Construction of tail: Four fins are spot welded to the tail cone and braced by a single set of box-type struts.


 
 
 
Type 2 No.50 Ordinary Bomb Model 1
  
 
Fuzes: A-3(f), B-2(a)
Overall Length: 78 inches
Length of body: 38 and 1/2 inches
Diameter of body: 15 and 1/2 inches
 
Thickness of wall:
-At base: 1 inch
-At nose: 7 and 1/2 inches
 Material of wall: Steel
 
Type of suspension: Horizontal
Suspension lug: Two guide studs on the bomb body position the Navy type suspension bands
 
Length of tail: 39 and 1/2 inches
Width of tail: 15 and 1/2 inches
Width of tail fins: 7 and 3/4 inches
 
Dimensions of tail struts:
-Length: 10 and 3/4 inches
-Width: 3 and 1/4 inches
-Thickness: 1/8 inch
Material of tail: Steel
 
Type of filling: Cast blocks of Type 98 explosive
Weight of filling: 148 pounds
Total weight of bomb: 1,100 pounds
Charge/weight ratio: 13%
 
Color and markings: The bomb is gray overall with a green-tipped nose, brown nose band and green tail struts.
 
Construction of body: The bomb body is constructed of one piece of machined forged steel.  A fuze pocket is drilled in the nose.  The after end of the body is threaded internally to accommodate a male base plate.  There is a fuze pocket drilled in the base plate.  A sheet steel tail cone is attached to the base plate by eight bolts.  Three trap doors in the tail cone give access to the fuze pocket.
 
Construction of tail: Four Navy type tail fins are spot-welded to the tail cone.  They are braced by a single set of box-type struts.
 
 
 
Next Time: Ordinary and other bombs

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