American Projectiles and Explosives - Explosive Bombs - "AN" Series (Part 2)

American Projectiles and Explosives



Explosive Bombs

"AN" Series

250-pound G.P. AN-M57 and AN-M57A1

Overall length: 45.4 inches
Body length: 36 inches
Body diameter: 10.9 inches
Wall thickness: 0.27 inches
Tail length: 12.1 inches
Tail width: 14.9 inches
Tail weight: 6 pounds

Filling: 50/50 Amatol
Weight of filling: 123.7 pounds
Total weight: 255.9 pounds
Charge/weight ratio: 48%

or

Filling: TNT
Weight of filling: 129 pounds
Total weight: 260 pounds
Charge/weight ratio: 50%





500-pound G.P. AN-M43 (Obsolescent), AN-M64, and AN-M64A1

Overall length: 56.8 inches
Body length: 45 inches
Body diameter: 14.2 inches
Wall thickness: 0.3 inches
Tail length: 13.9 inches
Tail width: 18.9 inches
Tail weight: 12.3 pounds


Filling: Amatol
Weight of filling: 262 pounds
Total weight: 510 pounds
Charge/weight ratio: 51.2%

or

Filling: TNT
Weight of filling: 267 pounds
Total weight: 525 pounds
Charge/weight ratio: 51%

or

Filling: Composition B
Weight of filling: 274 pounds
Total weight: 535 pounds
Charge/weight ratio: 51%


Remarks: The AN-M43, AN-M64, and AN-M64A1 are identical types except for the adapter booster which is employed in the base plate to receive the tail fuze.





1,000-pound G.P. AN-M44 (Obsolescent), AN-M65, and AN-M65A1

Overall length: 67.1 inches
Body length: 53.1 inches
Body diameter: 18.8 inches
Wall thickness: 0.5 inches
Tail length: 18.5 inches
Tail width: 25.4 inches
Tail weight: 21.5 pounds


AN-M44 (Amatol)
Weight of filling: 530 pounds
Total weight: 964 pounds
Charge/weight ratio: 54.9%

AN-M44 (TNT)
 Weight of filling: 558 pounds
Total weight: 990 pounds
Charge/weight ratio: 56%


AN-M65(Amatol)
Weight of filling: 530 pounds
Total weight: 965 pounds
Charge/weight ratio: 55.8%

AN-M65(TNT)
Weight of filling: 558 pounds
Total weight: 990 pounds
Charge/weight ratio: 56%


AN-M65A1(TNT)
Weight of filling: 558 pounds
Total weight: 990 pounds
Charge/weight ratio: 56%

AN-M65A1(Comp. B)
Weight of filling: 595 pounds
Total weight: 1,040 pounds
Charge/weight ratio: 57%






2,000-pound G.P. AN-M34 (Obsolescent), AN-M66, AN-M66A1, and AN-M66A2

Overall length: 90.4 inches
Body length: 70 inches
Body diameter: 23.3 inches
Wall thickness: 0.5 inches
Tail length: 25.7 inches
Tail width: 31.6 inches
Tail weight: 38.6 pounds


AN-M34 (Amatol)
Weight of filling: 1,063 pounds
Total weight: 2,049 pounds
Charge/weight ratio: 51.9%

AN-M34 (TNT)
 Weight of filling: 1,117 pounds
Total weight: 2,103 pounds
Charge/weight ratio: 53.1%


AN-M66(Amatol)
Weight of filling: 1,063 pounds
Total weight: 2,052 pounds
Charge/weight ratio: 52%

AN-M66(TNT)
Weight of filling: 1,117 pounds
Total weight: 2,106 pounds
Charge/weight ratio: 53%


AN-M66A1(TNT)
Weight of filling: 1,117 pounds
Total weight: 2,106 pounds
Charge/weight ratio: 53%

AN-M65A1(Comp. B)
Weight of filling: 1,142 pounds
Total weight: 2,140 pounds
Charge/weight ratio: 53.3%


Remarks: A heavier nose section distinguishes the AN-M66A2 from the AN-M66A1.





4,000-pound K.C. AN-M56 and AN-M56A1

Overall length: 117.3 inches
Body length: 94.9 inches
Body diameter: 34 inches
Wall thickness: 0.37 inches
Tail length: 28 inches
Tail width: 31.6 inches
Tail weight: 95 pounds


Filling: TNT
Weight of filling: 3,362 pounds
Total weight: 4,205 pounds
Charge/weight ratio: 80%

Filling: Amatol
Weight of filling: 3,245 pounds
Total weight: 4,095 pounds
Charge/weight ratio: 79%

Filling: 50/50 Amatol
Weight of filling: 3,238 pounds
Total weight: 4,232 pounds
Charge/weight ratio: 76.5%


Construction: The body consists of a nose forging, three rolled plate sections, and a forged base plate.  The nose forging is welded to the first plate section, and the three plate sections are welded longitudinally and circumferentially.  the female base plate is threaded to the tail section of the body.  The side walls have a minimum thickness of 0.3 inch and a maximum thickness of 0.5 inch.  Suspension is provided by two lugs welded to the case 30 inches apart (15 inches on either side of the center of gravity).  The normal box-type tail is modified on this bomb by eight additional strut rods to give increased stability for this large bomb.


Filling: The standard filling for this bomb as present is cast TNT, but some bombs in the future will be loaded with Tritonal.  A full length Auxiliary Booster M111 is employed to insure complete detonation.


Remarks: The 4,000-pound L.C. Bomb AN-M56A1 differs in that provision is made for a hoisting lug to be added at the center of gravity between the suspension lugs and also for two other suspension lugs to be screwed into the bomb body, 22.5 degrees removed, for suspension in British planes.

The AN-M56 and AN-M56A1 are not procured by the Navy at the present time.

Any future production will have inert nose and tail surrounds.





S.A.P. 500-pound AN-M58 (Obsolescent), AN-M58A1, and AN-M58A2; 
1,000-pound AN-M59 and AN-M59A1

500 lb
Overall length: 57.8 inches
Body length: 46.8 inches
Body diameter: 11.8 inches
Wall thickness: 0.75 inches
Tail length: 15.05 inches
Tail width: 16.18 inches
Tail weight: 11.4 pounds


1,000 lb
Overall length: 69.3 inches
Body length: 57.3 inches
Body diameter: 15.1 inches
Wall thickness: 1 inch
Tail length: 16.8 inches
Tail width: 20.7 inches
Tail weight: 17 pounds


AN-M58
Filling: TNT
Weight of filling: 160 pounds
Total weight: 472 pounds
Charge/weight ratio: 33.9%

AN-M58A1
Filling: TNT
Weight of filling: 162 pounds
Total weight: 494 pounds
Charge/weight ratio: 33%

AN-M59
Filling: TNT
Weight of filling: 320 pounds
Total weight: 995 pounds
Charge/weight ratio: 32%


Construction: S.A.P. bombs are of single-piece construction, either cast or spun, slightly streamlined in shape, with semi-pointed noses.  The threaded nose opening receives a fuze-seat liner and a steel nose plug, which can be removed, allowing an instantaneous nose fuze to be inserted when fragmentation effect is desired.  Suspension lugs are welded to the case in a manner similar to G.P. bombs; for dive bombing, trunnions on a band may be installed.  The box-type tail is characteristic of that used on G.P. bombs.


Filling: Cast TNT is being used currently, with a wax pad employed in the nose to cushion the explosive against premature detonation on impact with an armored target.  One Auxiliary Booster M104 is used, positioned just before the Adapter Booster M102.  In the future, Army S.A.P. bombs will have, as their main charge, Picratol, the filling now standard for the 2,000-pound S.A.P. Bomb M103.


Markings: Bombs having wax in the nose can be identified by the marking "with pad".


Remarks: In the AN-M58A1, 9.5 pounds of Amatol are removed and replaced by 31.5 pounds of steel to increase the penetration of the bomb.  To enable these S.A.P. bombs to be used with anti-withdrawal fuzes, the AN-M58A2 and the AN-M59A1 incorporate base-plate locking pins and the Adapter Booster M102A1, thus preventing removal of the base plate and adapter booster.  Present production eliminates Auxiliary Booster M104.

Next Time:"AN" Series (Part 3)

British Explosive Ordnance - Target Identification Bombs

British Explosive Ordnance

Target Identification Bombs Introduction

Target Identification bombs are designed to illuminate or mark a target for night bombing.  Not all TI bombs are filled with flare candles.  Some of them, such as the photoflash and sea marker TI bombs, contain special fillings.  But, because the majority of these bombs do contain candles, the following explanation is given in order to simplify the discussion of the bombs.

Three general types of candles are employed.  They are the non-delay, delay, and explosive candle.  The non-delay candle may give illumination of various colours, and, as the name indicates, the candle commences to function immediately on initiation.  This type of candle gives a sky marking effect due to the illumination given off during its fall.

The delay candle may also give illumination of various colours, but only after a period of delay, the length of which is determined by the delay unit contained in the candle.

The explosive candle is used in ground marker bombs, which contain a percentage of these candles to discourage interference with marker candles.  They contain an illuminant which burns until it ignites the explosive charge.  This explosive charge is also a component of the candle. 

The specific types of candles are listed as follows:

-Type A- These are non-delay candles of three minutes duration giving red, green, or yellow illumination.
  

-Type B1- These are delay candles which burn for a period of approximately two minutes with a red, green, or yellow light after a delay of two and one half or five minutes.
  

-Type B2- These are delay candles which burn with a red, green, or yellow light.  The delay and period of illumination depend upon the relative amounts of the two compositions.
  

-Type B3- These are long-delay candles which employ safety fuse to give a delay of from thirteen to thirty minutes.  The candles burn with a red, green, or yellow light for approximately three minutes.

-Type C- These candles burn with a red, green, or yellow light when initiated.  A delay composition separating the two illuminant sections provide a delay of two and one half to eleven minutes between sections.  This flare has two burning periods.
  

-Type D- These are explosive candles which burn with a red, green, or yellow light until the explosive charge is ignited.
  

-Type E- These are explosive candles whose illuminant is ignited by safety fuse after a delay of from fifteen to thirty-one minutes.  The illuminant burns with a red, green, or yellow light for approximately two minutes, after which it ignites the explosive charge.
  

-Type F- This is an explosive candle with two illuminant sections separated by delay composition.  The delay is from two and one half to nine minutes, depending on the amount of flare composition, which burns red, green, or yellow.  The second illuminant section ignites the explosive charge.
  

-Type G- These are non-delay candles equipped with parachutes to give a skymarker effect.  They provide red, green, or yellow illumination for approximately three minutes.
  

-Type H- This is a non-delay candle, which contains alternate coloured flare pellets of red and yellow, red and green, or yellow and green.  Each pellet burns for approximately fifteen seconds, giving a total burning time of approximately five and one-half minutes.
  

-Type J- This is another non-delay candle containing alternate colored pellets, as well as an explosive charge.  The flare burns for approximately two, three, or four minutes before exploding, depending on the number of pellets it contains.
  

-Type K- These non-delay candles are similar to and burn with the characteristic white illumination of the 4 pound Incendiary bomb, but have a different ignition system.
  

-Type L- These are white, non-delay candles similar to the Type K, but having a steel nose containing a high explosive charge, which explodes after a delay period subsequent to the illuminant's burning out.
  

-Type M- These are non-delay, change-colour candles similar to the Type H but having a three-minute overall burning time.  The colour changes are red and yellow, yellow and green, or red and green.
  

-Type N- These are non-delay, change-colour, explosive candles similar to the Type J, but having a period of illumination of two minutes and colour combinations of red and yellow, yellow and green, or red and green.
  

-Type P- This is a delay candle which burns red, yellow, or green before exploding.  The illuminating time depends on the relative quantity of delay composition and illuminant.
  

-Type Q- This is a delay candle which gives a succession of white flashes of long and short duration arranged in sequence as a Morse code signal.  A delay of three quarters of a minute to twenty-three minutes is provided by safety fuse.
  

-Type R- This is a non-delay candle, which gives a succession of white flashes of long and short duration arranged as a Morse code signal.
  

-Red Flash Unit- This flash unit gives a red flash of short duration after a predetermined delay period.

TI bombs are painted black overall with a coloured band around the nose plug to indicate flare color, and a 1/2-inch red filling band 8 inches from the nose.  The colour of the flares is also stencilled on the bomb body.  A red cross near the base of the bomb indicates that explosive candles are used.

The corresponding marks of the 250lb bombs No.1-6, 9, 10, 15, 16, 17, and 23-28 are identical in construction and operation, differing only in the fillings.  Consequently these bombs are groups for purposes of description.
  

The 1000lb TI bombs are larger versions of the 250lb size and correspond according to the "Number" in the designation.  Thus the TI 1000lb No.B22 would be the enlarged equivalent of the TI 250lb No.22 Bomb.

 
 

TI 250lb (Service)

(No.1 Mks I, IC, II, and III; No.2 Mks I, II, and III; No.3 Mks I, IC, II, and III; No.4 Mks I, IC, II, and III; No.5 Mk I; No.6 Mk I; No.9 Mk I; No.10 Mk I; No.15 Mk I; No.16 Mks I, IC, II, and III; No.17 Mks I and III; No.23 Mks IC, and III; No.24 Mks IC, and III; No.25 Mks IC, and III; No.26 Mk III; No.27 Mk III; and No.28 Mk III)

Overall length: 61.7 inches
Body diameter: 12 inches
Tail length: 27.2 inches
Tail width: 11.7 inches

Total weight: 220 pounds (approx.)


Fuzing: Nose Fuzes No.860 Mk II, No.848, or No.896 Mk I; Tail Fuze No.867 Mk I
  
Tail No.: Bombs Mks I and II; No.1 Mk II, No.35 Mk I, or No.75 Mk II; Bombs Mk IC and Mk III; No.75 Mks I or II.

Color and markings: The bomb body is painted black overall with a coloured band around the nose to indicate the flare colour, and a 1/2-inch red band 8 inches from the nose.

The colour of the flare is also stencilled on the bomb body.  A red cross near the rear of the bomb indicates that explosive candles are used.

  

Body Construction: The corresponding marks of the numbered bombs listed in this section are identical in construction and operation.  They differ only in the types of candles they contain.  Bombs Mk I and Mk II are nose-fuzed only, while Mks IC and III have provisions for both nose and tail fuzing.

Mk I Body - The Mk I bomb body consists of a heavy-gauge steel tube, to one end of which is welded a steel nose.  The after end of the body is closed by a tail plate held in place by six brass rivets.  The tail plate has two bayonet slots and a hole to be engaged by a transit base or the tail unit.

In the nose of the bomb is located the burster container, which houses a 3-ounce black powder ejection charge in a cambric bag or celluloid container.

Immediately abaft the burster container is the ejection plate, slightly smaller than the internal diameter of the bomb body, to which the central flash tube is welded.  The division disc, which separates the two layers of candles, is located at the opposite end of the flash tube.  The inside of the tube and both sides of the division disc are covered with primed cambric.  The igniter ends of both layers of candles rest against one of the primed discs.

The candles are held in position in the bomb body by felt or corrugate paper strips lining the inside of the body, a number of notched packing discs located beneath the tail plate, and a notched washer located against the ejection plate.  Three equi-spaced wooden battens, which pass through notches in the division plate, extend between the ejector plate and tail plate in order to force off the tail plate when the bomb functions.


Mk II Body: The Mk II bomb body is identical to the Mk I except for the use of a different type of suspension lug, and a light-gauge steel body which necessitates the use of a cast-iron weight welded inside the nose.

Mk III Body: The body of the Bomb Mk III consists of a light-gauge steel tube which has a steel nose welded to one end.  A cast-iron weight is welded inside the nose section.  The after end of the body is closed by a tail plate held in position by three locating studs, which engage three slots in the after end of the body, and is secured in position by three brass rivets.

The tail plate has two bayonet slots and a hole to be engaged by pins on a transit base, or the securing screws of the Tail Unit No.75 Mk I or Mk II.  A V-slot in the skirt of the tail plate, aligned with one of the locating studs and diametrically opposite the hole, receives the locating pin on the Tail No.75 to assure that the tail slot for the tail fuze lanyard is aligned with the suspension lug of the bomb.  The suspension lug is of the same type used on the Mk II body.

The burster container is similar to that of the Bomb Mk I, but is welded to the ejector plate and internally threaded to receive the forward end of the central flash tube.  The after end of this tube threads into the tail-fuze adapter, which is locked in place, and the whole adapter, which is locked in place, and the whole assembly is secured to the tail plate by a locking ring.

The two layers of candles are separated by a division disc, and a priming system, similar to the one used in the Bomb Mk I, is used to ignite them.  The candles are positioned as in the Bomb Mk I, but the wooden battens are not used as the central flash tube serves to force off the tail plate when the bomb functions.

 
Mk IC Body: This bomb is very similar to the Mk III, but as it employs a Mk I body converted for tail fuzing, its body is of thick-gauge steel, and consequently the nose weight is dispensed with.  The central tube is welded to the inner end of the burster container and is also welded to the ejector plate.




Functioning:
-Mks I and II: When the bomb is dropped, the fuze is set in operation and the bomb falls freely until the fuze explodes, igniting the burster charge of the bomb.  The flash from the burster charge passes through the flash hole in the burster container, and is conveyed to the primer cambric discs on the division disc by the primed cambric in the central flash tube.  These division discs ignite the candles.

Simultaneously, the gases from the burster charge expand and force the ejector plate toward the tail of the bomb.  The wooden battens force the tail plate and tail off the bomb, and the ignited candles are ejected and function in the normal manner.


-Mks III and IC: If the bomb is tail-fuzed only, the functioning of the fuze produces a flash which ignites the primed cambric in the central flash tube.  This primed cambric conveys the flash to the burster charge, which it ignites, and also passes through holes in the central tube to ignite the primed cambric discs on either side of the division disc.  These in turn ignite the candles.

Simultaneously, the explosion of the burster charge shatters the burster container at a weakened point, and the gases formed force the ejector plate toward the tail of the bomb.  The central tube forces off the tail plate and tail unit, and the candles are ejected to function in the normal manner.

If the bomb is nose-fuzed only, it will function in a similar manner except that he burster charge is ignited directly by the flash from the fuze magazine and the primed cambric tube is ignited by the burster charge.

  
Tail Construction: The Tail Units No.1 Mk II, and No.35 Mk I consist of a tail-cone to which a cylindrical strut is attached by four fins.  Three screws secure the tail to the tail plate of the bomb.

The Tail Assembly No.75 Mk I consist of a tail cone to which a cylindrical strut is attached by four fins.  Three screws attach the cone to the tail plate of the bomb, and a locating pin engages a V-slot in the tail plate to position the tail.  An arming assembly, consisting of an arming spindle, arming vanes, and an arming-spindle fork, is also present.  The Tail Mk II has cut-away fins to allow the arming vanes to be recessed for protection.  Both the Tails Mk I and Mk II have inspection windows in the tail cone.


Suspension: The bomb is suspended by a single lug, which is welded to the body.




Filling:
-No.1 Mk I - 60 Type A or 62 Type K candles
-No.1 Mks I and III - 60 Type K candles
-No.1 Mk II - 60 Type A candles
-No.2 Mk I - 56 Type A and 4 Type D candles, or 56 Type K and 4 Type L candles
-No.2 Mks II and III - 56 Type A and 4 Type D candles
-No.3 Mks I, IC, II, and III - 20 Type A and 40 Type B1 candles
-No.4 Mks I, IC, II, and III - 16 Type A, 40 Type B1, and 4 Type D candles
-No.5 Mk I - 30 Type A and 30 Type B1 candles
-No.6 Mk I - 26 Type A, 30 Type B1, and 4 Type D candles
-No.9 Mk I - 60 Type C candles
-No.10 Mk I - 60 Type B1 candles
-No.15 Mk I - 30 Type A and 30 Type D candles
-No.16 Mks I, IC, II, and III - 9 Type A, 46 Type B2, and 4 Type F candles
-No.17 Mks I and III - 60 Type M candles
-No.23 Mks IC and III - 9 Type A and 39 Type B2 candles
-No.24 Mks IC and III - 11 Type A, 45 Type C, 1 Type D, and 3 Type F candles
-No.25 Mks IC and III - 23 Type B2, 19 Type B3, 1 Type D, 1 Type E, and 2 Type F candles
-No.26 Mk III - 11 Type A, 27 Type B2, 18 Type C, 1 Type D, 1 Type F, and 2 Type P candles
-No.27 Mk III - 39 Type Q and 1 Type R candles
-No.28 Mk III - 16 Type A, 40 Type C, and 4 Type D candles

TI 250lb Multi-Flash No.7 Mks I and II, and No.21 Mks I, II, III, and IC (Service)

    

Overall length: 67.75 inches
Body diameter: 12 inches
Tail length: 27.2 inches
Tail width: 11.7 inches

Total weight: 220 pounds (approx.)

Burning Time: 0.1 seconds (individual unit)
 5 minutes (total contents of bomb)


Fuzing: Nose Fuze No.860 Mk II, No.848, or No.896 Mk I

Tail No.: No.1 Mk II, No.35 Mk I, or No.75 Mk II
  

Color and markings:  The bomb is painted black overall with a 1/2-inch red filling band located 8 inches from the nose.

MULTI-FLASH RED is stencilled in red letters on the nose, and in white letters on the body.

  

Body Construction:
-No.7 Mks I and II and No.21 Mks I and II Bodies: The actual construction of these bombs is the same as that of the No.1 TI Bomb Mk I except for a different arrangement of the filling, which requires a different type of central flash tube and priming, and eliminates the use of the division disc.

The flash units are packed around the central tube in seven layers, each of which contains 26 units; and an eight layer, containing 28 units, is positioned above the central tube.  The flash units are positioned so that the primed ends of each two layers contact one of the four primed cambric washers for purposes of ignition.  Each of these washers engages a strip of primed cambric, which is secured around a set of holes in the central tube.

The Bomb No.7 Mk II differs from the No.7 Mk I as the No.1 Mk II differs from the No.1 Mk I.


-No.21 Mk III and IC Body: The body, tail plate, burster container, and ejector plate of this bomb are the same as in the TI Bomb No.1 Mk I.  The interior arrangement of the Bomb No.21 Mk III differs from the No.7 and No.21 Mks I and II in that he central flash tube extends completely through the bomb to the tail fuze pocket, thus displacing two of the flash units.  The Bomb No.21 Mk IC differs from the No.21 Mk III as the No.1 Mk IC differs from the No.1 Mk III.


Functioning:
-No.7 Mks I and II, and No.21 Mks I and II: The explosion of the fuze magazine ignites the burster charge, which transmits its flash to ignite the primed cambric tube, the primed strips around the central tube, the primed washers, and the flash units.  The ejection of the flash units is the same as for the Bomb No.1 Mk I.

-No.21 Mk III and IC Bombs: The operation of these bombs, when nose-fuzed, is the same as that for the Mks I and II of the TI Bombs No.7 and No.21.  When tail-fuzed, the flash is transmitted from the tail fuze to the nose burster by the primed cambric tube which meanwhile ignites the units.  Ejection is the same as for the Bomb No.1 Mk III.


Tail Construction: Same as for the No.1 TI Bomb tails.


Suspension: The bomb is suspended by a single lug, which is welded to the body.


Filling:
-No.7 Mks I and II, and No.21 Mks I and II: 210 red flash units
-No.21 Mks III and IC: 208 red flash units.




Remarks: This bomb is used to distinguish genuine ground markers from one simulated by the enemy.

TI 250lb Spot Fire, No.8 Mks I, IC, II, and III (Service)
   

Overall length: 57.75 inches
Body diameter: 12 inches
Tail length: 27.2 inches
Tail width: 11.7 inches

Total weight:
-Mk I and IC: 205 pounds
-Mk II and III: 215 pounds

Burning time: Red, 20 min (approx.); Green and Yellow, 1 hour (approx.)


Fuzing: Nose Fuze No.860 Mk II, No.848, or No.896 Mk I; Tail Fuze No.867 Mk I

Tail No.: No.1 Mk II, No.35 Mk I, or No.75 Mk II
  

Color and markings: The bomb is painted black overall with a 1/2-inch red filling band, 8 inches from the nose.

SPOT FIRE in red, green, or yellow letters, according to the filling, is stencilled on the nose;
and SPOT FIRE, preceded by the appropriate colour, is stencilled on the body in white.

  

Body Construction:
-Mk I Body: The bomb body, tail plate, and burster are the same as those used in the TI Bomb No.1 Mk I.  However, the burster container has a crossed slit on its inner end, filled with solder, to pass the flash from the burster charge to an igniter located in the impregnated bale.

The ejector plate is held by screws against a steel ring welded to the inside edge of the nose.  The ejector plate has a central flashhole covered by a thin copper disc, which has two crossed slits filled with solder.  Three locating pins are welded to the ejector plate, and locate the bale igniter centrally over the flash hole.

The filling bale consists of rolled cotton wool enclosed in cheesecloth, and held together by wire and steel bands.  Six wooden battens extend from the ejector plate to the tail plate and serve to force off the tail plate when the bomb functions.

The igniter at the nose end of the bale consist of an igniter base into which a tube filled with incendiary composition is screwed.  A central hole in the igniter base is located above the flash hole in the ejector plate, and has a similar closing disc of copper with a solder-filled cross slit.

A diaphragm, soldered to the bomb body under the tail plate, holds the bale in place.


-Mk II Body: The Bomb Mk II differs from the Mark I only in general body construction as the TI Bomb No.1 Mk II differs from the No.1 Mk I.


-Mk III Body: The Bomb Mk III is similar in body and tail plate construction to the TI Bomb No.1 Mk III.  The internal arrangement of the filling is similar to that in the Bomb No.8 Mk I.  However, as this bomb is arranged for tail fuzing, a length of instantaneous fuze leads from the tail fuze pocket, through a steel tube located along the inside of the bomb body, and into the forward end of the burster container.  A burster capsule is attached to each end of the fuze.


-Mk IC Body: The Mk IC bomb differs from the Mk III as the TI Bomb No.1 Mk IC differs from the No.1 Mk III.



Functioning:
-Mk I and II: The functionining of the fuze ignites the burster charge, which simultaneously ruptures the three soldered cross slits to initiate the incendiary charge in the igniter, and forces the ejector plate toward the rear, causing the wooden battens to push off the tail plate and eject the bale.  The incendiary charge in the igniter heats its tube until the impregnated cotton wool in the bale catches fire.

-Mk III and IC: The operation, when nose-fuzed, is the same as for the Mks I and II, and, when tail-fuzed, differs only in that the flash from the tail-fuze magazine is transmitted to the burster container by the instantaneous fuze, where the burster charge is ignited by the burster capsule.


Tail Construction: Same as for the TI Bomb Tails No.1


Suspension: The bomb is suspended by a single lug, which is welded to the body.



Filling: The filling consists of a bale of color-impregnated cotton wool.


  

TI 250lb Photoflash, No.11 Mk I, No.12 Mk I, and No.13 Mks I and II (Service)
    

Overall length: 67.75 inches
Body diameter: 12 inches
Tail length: 27.2 inches
Tail width: 11.7 inches

Total weight: 220 pounds (approx.)
Flash illumination period: 0.1 second


Fuzing: Nose Fuze No.860 Mk II, No.848, or No.896 Mk I

Tail No.: No.1 Mk II, No.35 Mk I, or No.75 Mk II
  

Color and markings:  The bomb is painted black overall with a 1/2-inch red filling band 8 inches from the nose.  A coloured band on the nose indicates the color of the candles in the bomb, while the colour is also stencilled in the appropriate shade on the body.

PHOTOFLASH is stencilled in white letters on the nose.

  

Body Construction: The Bombs No.13 Mk I and Mk II have bodies, base plates, and burster containers identical to those of the corresponding marks of the TI Bombs No.1.

The ejector plate is perforated and has a wooden block attached to it by screws.  This block houses the photoflash igniter.  The photoflash unit has a thin metal body, and a central burster tube filled with black powder.

The candles are arranged in two layers around the central flash unit.  A primed cambric washer is located between the primed ends of the two layers.


Functioning: When the fuze functions, it ignites the burster charge, whose flash initiates both the photoflash igniter and the primed cambric disc, which ignites the candles.  The expanding gases of the burster eject the flare contents.  The candles function in their normal manner, and the photoflash unit explodes with a vivid, white flash about two seconds after ejection.


Tail Construction: Same as for the No.1 TI bomb tails.


Suspension: The bomb is suspended by a single lug, which is welded to the body.


Filling: The filling of the Bomb No.13 consists of a photoflash unit, and 40 Type A candles.


Remarks: Both the 250lb TI Bombs No.11 and No.12 were manufactured in limited numbers, and have been superseded by the Bomb No.13.  Both bombs were similar to the No.13 but the No.12 was filled with 40 Type B1 candles packed around the photoflash unit, while the No.11 contained no candles, the space being packed with sand to act as a ballast.

 

TI 250lb Skymarker (Service)
(No.14 Mks I, IC, II, and III, and Change Color, No.18 Mks I, IC, II, and III)

Overall length: 67.75 inches
Body diameter: 12 inches
Tail length: 27.2 inches
Tail width: 11.7 inches

Total weight: 220 pounds (approx.)
Burning Time: No.14 - 3 minutes; No.18 - 5 and 1/2 minutes


Fuzing: Nose Fuze No.860 Mk II, No.848, or No.896 Mk I; Tail Fuze No.867 Mk I

Tail No.: No.1 Mk II, No.35 Mk I, or No.75 Mk II
  

Color and markings:  The bombs are painted black overall with a 1/2-inch red filling band 8 inches abaft the nose.

The Bombs No.14 have a coloured nose band to indicate the colour of the candles used, as well as having the colour stencilled on the bomb body.  SKYMARKER is stencilled on the nose and body in white.

The Bomb No.18 has two 1/2-inch rings around the nose to indicate the colours are also stencilled on the bomb body.  CHANGE COLOUR is stencilled on the nose and body in white.

  

Body Construction:
-No.14 Mks I and II, and No.18 Mks I and II: The body, tail plates, and burster containers of these bombs are the same as those of the No.1 Mks I and II.  In addition, the No.14 Mk I has a nose weight of cast iron.  The Bombs No.14 and No.18 have no central flash tube, but use double-length candles, whose primed ends rest against a primed cambric disc on the perforated ejector plate.  Steel tubes may be substituted for wooden battens.

-No.14 Mks III and IC, and No.18 Mks III and IC: The body, tail plate, burster container, central flash tube, and tail-fuze adapter of these bombs are identical to those on the corresponding marks of the TI Bombs No.1.  The Nos.14 and 18 have an unperforated central tube and no division disc, as double-length candles are used.  The candle's primed ends rest against a primed cambric disc on the perforated ejector plate.


Functioning:
-No.14 Mks I and II, and No.18 Mks I and II: Functioning of the fuze ignites the burster charge, which flashes through the perforated ejector plate to ignite the cambric and candles, and ejects the candles after forcing off the base plate.

-No.14 Mks III, and IC, and No.18 Mks III and IC: If nose-fuzed, these bombs fuction the same as the Mks I and II, except that the central tube instead of battens forces off the tail plate.  If tail-fuzed, the flash of the fuze is carried by the primed cambric tube to the nose burster charge, after which the operation is the same.


Tail Construction: Same as for the TI Bomb Tails No.1


Suspension: The bomb is suspended by a single lug, which is welded to the body.


Filling:
-No.14: 24 Type G candles
-No.18: 24 Type H candles

TI 250lb, Sea Marker, No.19 Mks I and II (Service)

Overall length: 67.75 inches

Body diameter: 12 inches
Tail length: 27.2 inches
Tail width: 11.7 inches

Total weight: 180 pounds (approx.)
Burning time: 5 to 8 minutes (approx.)


Fuzing: Nose Fuze No.860 Mk II, No.848, or No.896 Mk I

Tail No.: No.1 Mk II, No.35 Mk I, or No.75 Mk II
  

Color and markings: The bomb is painted black overall with a 1/2-inch red filling band 8 inches from the nose.

SEA MARKER-FLAME is stencilled on the nose, and SEA MARKER is stencilled on the bomb body.

Body Construction: The body, tail plate, and burster container of the Bombs No.19 Mk I and Mk II are the same as those of the corresponding marks of the TI Bombs No.1.

The ejector plate is secured by screws to a ring, which is welded to the inner edge of the nose.  A canister of thin steel rests on the ejector plate, and is held in position by a thin diaphragm soldered to the inside of the body just beneath the tail plate.  The inside of the canister is divided in two by a thin dished plate.  The upper part of the canister forms a buoyancy chamber, while the lower part is filled with a sodium phosphide-phosphorus mixture.  The lower part of the canister is pierced by several water-inlet holes, which are covered by wire netting.  Six wooden battens extend along the outside of the canister to force off the tail plate.


Functioning: When the fuze functions, the flash from its magazine ignites the burster charge, which forces the ejector plate aft, shearing its securing screws and ejecting the canister.

When the canister falls into the sea, the buoyancy chamber keeps it afloat while water enters the inlet hole and reacts with the chemical filling to produce impure phosphine gas.  This gas escapes through the water-inlet holes and ignites spontaneously on contact with air go vie a luminous flame about three feet long, as well as a cloud of dense smoke.


Tail Construction: Same as for the No.1 TI bomb tails.

 

Suspension: The bomb is suspended by a single lug, which is welded to the body.

  

Filling: The bomb is filled with a sodium phosphide-phosphorus mixture.

 

TI 1000lb (Service)
(No.B2 Mk I, No.B4 Mk I, No.B16 Mk I, No.B22 Mk I, No.B24 Mk I, No.B25 Mk I, No.B26 Mk I, No.B28 Mk I, and No.B29 Mk I)
  

Overall length: 73.6 inches
Body length: 53.6 inches

Body diameter: 17 inches

Tail length: 20 inches
Tail width: 17.4 inches

Total weight: 560 pounds (approx.); No.B29 - 730 pounds (approx.)

Fuzing: Tail Fuze No.867 Mk I, or Nose Fuze No.896 Mk I.
 Bomb No.B29 is nose-fuzed only, with Nose Fuzes M111, M111A1, M111A2, No.42 Mks II, II*, IM, or III, No.848 Mks I-V, or No.849 Mks I or III.

Tail No.: No.57 Mk I
  

Color and markings: Black overall,
red band around nose end, and 2-inch ring around nose to indicate colour of contents,
"X" stencilled in red when explosive candles are used.

Body Construction: The bomb consists of a cylindrical body with a dome-shaped nose cap welded on.  The after body of the bomb consists of a sheet steel body cone.  This after cone section is welded to a steel tail plate, which is press-fitted into the after end of the central cylinder.  A small notch is cut out at one point on the circumference of the tail plate.  A projection from the end of the central body engages in this notch, properly positioning the tail plate and tail assembly.  A steel tube, running axially through the bomb, is welded to a burster container at the nose end, and passes through a central hole in the tail plate at the tail end.  The fuze adapter is threaded to this tube abaft the closure plate, holding the closure plate and tail assembly tightly in the bomb body.

Three banks of flares are placed in the central body cylinder.  The ignition ends of the flares bear against one of two equi-spaced, primed cambric discs.  A primed cambric tube is inserted in the central tube, and holes in the central tube provide a lead out to each of the primed cambric discs.

An ejection plate is located just before the first bank of flares and just abaft the hollow nose portion of the bomb.  This ejection plate is welded to the central tube.  In the nose is a short burster container with a flash hole in its after end, and additional flash holes located circumferentially around its upper portion.  These latter holes lead into the empty cavity formed by the nose portion of the bomb and ejection plate.

The Bomb NoB29 is the only bomb of this series which does not contain candles.  It is similar to the Bomb No.B2, but has no primed cambric tube in the central tube, and no primed cambric, cardboard, or millboard washers in the bomb body.  The bomb is filled with a quantity of powdered, coloured pigment.




Tail Construction: The Tail No.57 Mk I consists of a tail cone to which a cylindrical strut is fastened by four fins.  The arming assembly consists of arming vanes, an arming spindle, and an arming fork, which is positioned inside the cone by a spider.  A locating slot in the forward edge of the cone engages a locating pin on the bomb.  The cone is secured to the bomb by four bolts, housed in the cone ring which is riveted to the inside of the cone.  The cone also has two celluloid inspection windows set into it.


Functioning: These bombs, with the exception of the No.B29 which is always nose-fuzed, are generally tail-fuzed.  When the tail-fuze magazine functions, the flash ignites the primed cambric tube in the central tube, which ignites the primed cambric washers and the candles.  The cambric tube also passes the flash to the nose burster, which explodes, ejecting the candles.  When the nose-fuzed, the flash from the nose-fuze from the burster then ignites the primed cambric tube, washers, and candles in turn.  The candles are ejected simultaneously.

 
Suspension: The bombs are equipped with a single lug for British suspension, and two lugs 180 degrees removed, for suspension in American aircraft.
  

Explosive Components: A number of combinations of candles may be incorporated in the 1000lb bomb.  The following list gives the combination used in the various bombs:

-No.B2- 200 Type A and Type D candles
-No.B4- 62 Type A, 124 Type B2, 10 Type D, and 4 Type F candles
-No.B16- 200 Type A, and Type B1 or B2 candles
 -No.B22- 140 Types A, C, D, and F candles
-No.B24- 200 Types A, C, D, and F candles
-No.B25- 12 Type A, 121 Type B3, and 9 Type E candles
-No.B26- 31 Type A, 93 Type B2, 62 Type C, 6 Type D, 4 Type F, and 4 Type P candles
-No.B28- 62 Type A, 104 Type C, 10 Type D, and 4 Type F candles
-No.B29- Red, green, yellow, or blue pigments


Remarks: This series of bombs is a larger version of the 250lb TI Bombs, with the exception of the No.B29 which has no parallel in the 250lb series.  The individual bombs within the 1000lb series, including the Bomb No.B29, differ mainly in their contents.  The Bomb No.B29 is used as a daylight skymarker.  It emits a cloud of coloured pigment which is effectively visible for about four minutes.  This bomb is called the "Skymarker Puff."

Next Time: Flares and Photoflash Bombs

British Explosive Ordnance - Obsolete Bombs

British Explosive Ordnance

Obsolete Bombs Introduction


The various bombs of different types included in this section have all been declared obsolete, but because of the possibility that they still may be encountered, it is deemed desirable to give complete information regarding them.

Older obsolete bombs, included only as a matter of interest, are listed in chart form at the end of the chapter.









AT 9lb, Mk I  (Obsolete)

Overall length: 14 inches
Maximum body diameter: 4 and 1/2 inches squared

Total weight: 8.5 pounds
Charge/weight ratio: 80%

Fuzing: Tail Fuze No.847
  

Color and markings:  Dark green overall,
1/2-inch red band around nose.

  

Body Construction: The body is made of thin metal, approximately rectangular in shape, having a square cross section with rounded corners.  It tapers slightly from the rear toward the nose.  The body is closed at the nose end by a front cover housing a nose cup, which is taped and cemented in place.  The nose cup of the rear bomb forms a safety device for the fuze in the front bomb of a pair, as bombs are dropped in pairs.  The rear cover is located approximately in the middle of the bomb.  The bomb incorporates a steel, cone-shaped charge.


Tail Construction: The tail is integral with the body, being only a continuation of the thin metal case.  The rear bomb of a pair has a retarder plate to pull the rear bomb free of the front one when dropped from the container.  The tail also has a safety tube of light-gauge metal with a  cardboard inner sleeve, forming a safety device for the fuze of the rear bomb of a pair.  A locating plate near the rear of the safety tube locates the tube in the tail of the bomb.

 
Suspension: These bombs are carried in the 250lb Small Bomb Container, which holds 24 bombs.  They are loaded in pairs, with the nose of the rear bomb houses in the tail of the front bomb.


Filling:
-Exploder: CE pellet housed in the bottom of the exploder container
-Filling: Nobel's explosive No.808, with shaped charge effect.


Remarks: The bomb is designed for use against tanks and armored vehicles.  It will blow a hole approximately nine inches in diameter in armor plating 2 inches thick, and is effecting at striking angles up to 45 degrees.

The 9lb AT Practice Bomb Mk I is approximately the same shape, size, and filled weight, and has the same approximate ballistic characteristics.  However, it has neither exploder nor detonator.  Its body breaks up on impact with the target to release a white filling, clearly visible from the air.

HE 20lb Mk I (Obsolete)

   

Overall length: 25 inches
Body length (w/o tail adapter): 11 inches (approx.)
Body diameter: 5.175 inches
Tail length (w/ tail adapter): 12 inches (approx.)
Tail width: 6 inches (approx.)

Total weight: 27 pounds (approx.)
Charge/weight ratio: 20% (approx.)

Fuzing: Nose Pistol No.16
  

Color and markings:  Dark green overall,
1/2-inch red band and 1 inch light green band around nose.

  

Body Construction: The bomb has a steel, semi-steel or malleable-iron body, hollow and open at both ends, with the forward end threaded internally to receive the nose adapter, and the after end internally threaded to take the tail adapter.  The nose adapter has three different-sized threads, to take the detonator-holder and the exploder container from the rear,a nd the pistol from the front.  The flange of the nose adapter is externally threaded to receive a screw-on pistol cover.  The tail adapter is tapered to conform to the rearward streamlining of the body, with a central bore threaded to receive the tail rod.


Tail Construction: The bomb has a wooden tail cone, conforming to the streamlined shape of the body.  Two diametrical saw-cuts at right angles extend from the after end, over a slightly greater length than that of the tail vanes, to accommodate the four sheet-metal tail vanes, which are made in integral pairs.  The tail cone is bored axially to take the tail rod, and fits into the cavity in the tail adapter.


Suspension: A wrought-iron or mild steel suspension lug is riveted to the bomb body.


Filling:
-Exploder: 3 sold and 1 perforate CE pellets.
-Filling: 5 pounds (approx.) TNT


Remarks: This bomb was intended for attacking personnel, air strips, and road transports.

RL 112lb Mks V, VI, and VIII (Obsolete)
   

   

Overall length: 18 inches
Body diameter: 8 inches
Wall thickness: Solid body

Total weight: 10 pounds

Fuzing: Nose Pistol No. 8 Mk I, or Nose Pistol No.19 Mks I and II; Tail Pistol No.5B Mks I and II
  

Color and markings: Yellow overall,
1/2 inch red band around nose,
1 inch light green band around body.

  

Body Construction: The body of these bombs is a single streamlined casting, steel for Mks V and VII and iron for Mk VI, threaded at the nose and tail to take adapters for the central exploder tube.


Tail Construction:
Mk V: The tail of the Bomb Mk V consists of four tail fins, which fit over the body and are fastened in place with screws.  Two sets of box-type struts reinforce the tail fins.


Mks VI and VII: The tail assembly of the Bombs Mk VI and Mk VII consists of a tail cone, which slides over the after end of the bomb body and sis secured by a locknut on the exploder tube.  Four tail fins are riveted on the cone and are held in place by two sets of box-type struts.


Suspension: The Bomb Mk V has a U-shaped eye-bolt secured to the body with screws at the center of gravity.

The Bombs Mk VI and Mk VII have a U-shaped eye-bolt fastened to a suspension band around the center of gravity.


Filling:
-Exploder: TNT and CE pellets
-Filling: Amatol 80/20, or TNT
  

GP 120lb Mks I and II (Obsolete)
     

Overall length: 42.4 inches
Body length: 21.5 inches
Body diameter: 8.1 inches
Wall thickness: 0.5 inches
Tail length: 15.7 inches
Tail width: 8 inches

Total weight: 120 pounds (Amatol 80/20)
Charge/weight ratio: 25%

Fuzing: Nose Pistol No.19; Tail Pistol No.21
  

Color and markings:  Yellow overall,
1/2-inch red band around nose and 1 inch light green band around body,
longitudinal green bar on body and tail indicates explodering scheme..

  

Body Construction: The body is a streamlined steel casting or forging, threaded at the nose to take the nose adapter, which holds the central exploder tube.  At the other end of the casting is a threaded base plug through which the exploder tube passes.  Welded to the end of the casting is a streamlined section of thin metal, containing no explosive, which is tapered to take the tail ring.  The exploder passes through this section also.


Tail Construction: A truncated cone fits over the rear section of body and is held to it by a locknut over the exploder tube.  Three mild-steel fins are fastened to the cone, and are reinforced by a cylindrical strut.


Suspension: The bomb uses a single suspension lug secured to the body by four screws.


Filling:
-Exploder: TNT and CE pellets
-Filling: 36.5 pounds TNT, or 30 pounds Amatol 80/20

 

GP 500lb Mks I, II and III (Obsolete)
     

Overall length: 68.7 inches
Body length: 35.7 inches
Body diameter: 13 inches
Wall thickness: 7/8 inches
Tail width: 13 inches

Total weight: 509 pounds (TNT)
Charge/weight ratio: 28%

Fuzing: Nose Pistol No.19; Tail Pistol No.17 or 22
Tail No.: No.1 Mk I (Mk III bomb only)
  

Color and markings:  Yellow overall,
1/2-inch red band around nose and 1 inch light green band around body,
light green bar on body and tail indicates explodering scheme..

  

Body Construction: The body is a streamlined steel casting or forging threaded at the nose to take the nose adapter, which holds the central exploder tube.  At the opposite end is a threaded base plug through which the exploder tube passes.  Welded to the after end of the body is a streamlined cone of thin metal, containing no explosive, which is tapered to take the tail ring.  The exploder also passes through this section.


Tail Construction: The tail has a truncated cone, which fits over the rear section of the body and is held to it by a locknut over the exploder tube.  Four mild-steel fins are fastened to the cone, and are reinforced by a cylindrical strut.


Suspension: The bomb is suspended by a single suspension lug secured to the body by four screws.


Filling:
-Exploder: TNT and CE pellets
-Filling: 143 pounds TNT, or 134 pounds Amatol 80/20

Remarks: The tail fins are usually painted red when time pistols are used.

HC 2000lb Mk I (Obsolete)

   
Overall length: 162 inches

Body length: 99.5 inches

Body diameter: 18.5 inches
Wall thickness: 0.19 inches
Tail length: 60 inches
Tail width: 18.6 inches

Total weight: 1842 pounds
Charge/Weight ratio: 73%

Fuzing: Nose Pistol No.27, 42, or 44
Tail No.: No.32 Mk I, or No.10 Mk I or II, or Parachute Attachment
  

Color and markings: Dark green overall,
1/2-inch red band 3 and 1/2 inches from front edge of cylindrical shell,
2-inch light green band 16 inches from edge.

Body Construction: The body consists of a cylindrical steel shell with a hollow, conical nose piece welded to one end, parallel sides, and a closing plate bolted to an angle ring which is welded in position a short distance within the other end.  A radial strengthening band is welded internally at the center of gravity, and its ends are welded to a steel block.  Holes tapped through the shell and steel block receive the suspension lug screws.  Side pockets for supplementary fuzing are present near the base end, but are not used.  The shell is strengthened longitudinally by two channel beams welded to each end of a central steel block and to the shell interior.


Tail Construction: The Tail No.32 Mk I assembly consists of a cylinder of light-gauge metal with a metal tray secured in its forward end and a strengthening ring in its open rear end.  The tray has a series of equispaced bayonet dogs for attaching to the body bayonet joints welded to it.  The cylinder has a number of openings to give it stability.

The parachute attachment has a parachute 5 feet, 6 inches in diameter, attached to a metal tray having bayonet dogs for attaching it to the body.  The parachute is retained by waterproofed fabric and a retaining pin.  The retaining pin is attached to a static cord stitched on the outside of the last protective panel, and connected to the bomb carrier or aircraft.  On release the cord pulls the retaining pin and chute free, and breaks off from the plane when the chute is extended.
 

Suspension: The bomb is suspended by a single suspension lug bolted to the body and an internal steel block at the center of gravity.  The screw holes are closed by transit screws until the bomb is to be used, at which time the lug is attached.
  

Explosive Components:
Exploders: A central exploder tube extends from the nose exploder container.  The tube contains eight 33 and 1/4 ounce TNT exploders.  The exploder container contains a 9 ounce TNT exploder.

Filling: 1340lb Amatol 60/40 sealed at each end with an approved composition


Remarks: This bomb may be fitted with a nose attachment of light-gauge metal to retard the bomb in flight.  It consists of a cylinder fitting over the forward end of the body shell and projecting forward beyond it around the conical nose piece.  Two side fuzing pockets are usually not used, but might contain the Time Pistol No.47.

 

AS 35lb Mks I and II (Obsolete)

Overall length: 29.2 inches

Body length: 17.2 inches

Body diameter: 7 inches
Wall thickness: 0.064 inches
Tail length: 17 inches (approx.)
Tail width: 7 inches

Total weight: 35 pounds
Charge/Weight ratio: 46%

Fuzing: Nose Fuze No.866
  

Color and markings: Dark green overall,
1/2-inch red band and 1-inch light green band around body.

Body Construction: The bomb has parallel sides, with a nose adapter and a tapered rear section.  A tail adapter secures the tail to the body.  The explosive charge is cone shaped, employing the principle of Munroe shaped charge.  A cylindrical nose attachment is welded onto the nose adapter by four tack welds.  The exploder is in the rear of the body, and is initiated by a flash from the nose fuze, communicated through the supporting tube extending from the nose cavity to the exploder.


Tail Construction: The tail consists of a long hollow tube with a cylindrical strut attached to it by six fins.  The tail threads into the tail adapter, and is secured by a locking screw.  The six fins are formed by three sets of W-shaped supports welded to the tail tube.
 
Suspension: The Bomb Mk I has a single lug for suspension in aircraft.  The Mk II has no lug, as it is intended to be fired from shipboard.
  

Explosive Components:
Exploder: CE pellets
Filling: 16lb RDX/TNT 60/40.  The after end is sealed by a 1/4-inch topping of TNT.

Remarks: The Bomb Mk I was designed for use by Coastal Command and was intended to be dropped from aircraft.  The Bomb Mk II has no suspension lug, and is intended for spigot projection from ships.



 






DC 450lb Mk VII (Obsolete)

Overall length: 67.25 inches
Body length: 27.75 inches

Body diameter: 17.5 inches
Tail length: 32 inches (approx.)
Tail width: 17.5 inches

Total weight: 450 pounds
Charge/weight ratio: 64%

Fuzing: Mk X** pistol and depth adjuster
  

Color and markings: Dark green overall with circumferential red and green bands

Body Construction: The body consists of a welded cylindrical case, closed by two covers connected by a central tube called the primer tube.  This tube, housing the primer, pistol, and depth adjuster, has an internal diameter of 3.5 inches.  Three lifting eyes with rings are provided, one on the cover at the primer end, and two on the cover at the opposite end.  The cover at the primer end has two filling holes which are closed by bungs.  It may or may not have a nose attachment and tail.  The bomb is carried on aircraft with the primer end forward, except when fitted with the parachute attachment, in which case the pistol and depth adjuster are forward.


Nose Attachment: The bomb may use a hemispherical hollow nose held on by the side straps, which also secure the tail assembly.


Tail Construction: The tail, when fitted, consists of a cylindrical strut attached to a hollow tail cone by four fins.  Three brackets, equispaced around the cone, are fitted to take the ends of the straps which secure the nose and tail attachments, both of which break off on impact with water.  The bomb may have a parachute attachment on the primer end if dropped from high-speed aircraft.

 
Suspension: The bomb is suspended by a single lug on a suspension band around the center of gravity.


Explosive Components:
Filling: 290lb Amatol

IB 25lb Mks I and II (Obsolete)

Overall length: 32.6 inches
Body diameter: 5.03 inches

Tail length: 13.55 inches

Total weight: 25 pounds

Fuzing: Simple impact striker
  

Color and markings: Dull red overall,
two 1/2-inch black bands separated by 1/2-inch red band painted around the nose.

Description: The Bomb Mk I consists of a cylindrical steel tube secured to a hollow, sharp-pointed nose by a nose adapter (built up externally to streamlined form by a cardboard fairing), a column of seven closed containers, termed fire-pots, accommodated in the body tube, a flanged base adapter which affords a mounting for a cap holder, a tail cone with a cylindrical tail vane secured to it by four vane supports, and a tail tube which accommodates a striker pellet, with a shear wire and creep spring, and a safety rod.

Each of the seven fire-pots consists of a cylindrical container made of magnesium alloy and formed with a central tube, which communicates, through a fire hole, with a recess in a central boss on the base of the container.  The container is closed by a magnesium alloy lid, which has a shallow central recess in its outer side.  Holes through he lid place this recess in communication with the interior of the container.  The ignition cap contains a layer of gunpowder and a layer of detonating composition.

The central tube of each of the fire-pots houses a delay charge and is surrounded by a delay charge and a priming charge for the thermite and magnesium filling, which occupies the remainder of the annular chamber in the fire-pot.  A loop of quickmatch extends into the bore of the central tube and has its two ends carried out through the slots in the tube and through two of the holes in the lid.  An ejection charge of gunpowder is retained in the recess in a central boss of each fire-pot by a paper disc, which is secured in position by shellac.

The tail cone fits over the flange of the base adapter and is held assembled to the bomb body by a tail nut, which screws onto the rear end of the tail tube against a tail adapter.  The tail adapter fits into the rear end of the tail cone.

The striker pellet has a sharp point at the forward end and is held in the safe position by a shear wire passed through holes in the striker pellet and tail tube.  The ends of the shear wire are soldered to prevent removal.  The rear end of the striker pellet receives the forward threaded end of the safety rod.  The creep spring is house in the forward end of the tail tube and bears against the cap holder and the striker pellet.  The safety rod passes through the tail tube and is screwed into the threaded bore of the striker pellet.

The Bomb Mk II has only a slight difference in the tail plate.


Parachute Attachment: Either a Parachute Attachment No.1 Mk I or a No.1 Mk II may be used with this bomb.  The Attachment No.1 Mk I consists of a small parachute housed in a container of sheet metal, consisting of a cylindrical housing plate and a cover.  It fits loosely in the cylindrical strut of the bomb tail.  The chute is 15 inches in diameter and vented at the peak.  The Attachment No.1 Mk II is similar, except that it is housed in a collapsible cardboard container between cardboard packing discs.


Striker Attachment: There are two striker attachments, the No.1 Mk I, and the No.1 Mk II.  No.1 Mk I consists of a coupling fork, snatch rod, striker rod, coupling socket, and a retaining sleeve, which houses a spring.  The No.1 Mk II is similar, except that the coupling fork is fitted with a quick-release pin.


Functioning: Whent he bomb using the Parachute and Striker Attachments No.1 Mk I is released, the cover pulls the chute out.  The chute opens and pulls the snatch rod against the action of the spring until the striker rod retaining balls escape into the annular recess in the retaining sleeve.  The striker rod then moves down against the striker pellet.  On impact, the inertia of the rod and pellet combine to shear the shear wire, overcome the creep spring, and pierce the ignition cap, igniting the blowing charge and blowing the base adapter and complete tail and parachute assembly from the body tube.  The quickmatch, which passes through the lid and into the central tube of the rearmost magnesium alloy fire-pot, is also ignited, and, in turn, the quickmatch ignites the delay charges in and around the central tube of the fire-pot.

While the central tube delay charge is burning through, the outer delay charge initiates the surrounding priming charge, which, in turn, ignites the incendiary composition around it.  Meanwhile, the central delay charge burns through and fires the ejection charge in the base of the fire-pot.  This has the effect of ejecting the activated fire-pot from the bomb and also igniting the quickmatch of the second fire-pot, etc.  Each ejected fire-pot will continue to burn for approximately 10 minutes; the magnesium alloy container and lid being consumed.

Finally, the quickmatch in the lod closing the nose of the bomb is ignited by the last ejection charge and initiates the priming charge, which, in turn, ignites the incendiary composition of the nose, and provides an additional fire source.

When used with the Parachute and Striker Attachment No.1 Mk II, the parachute is blown out of the cylindrical shroud on the tail and the chute opens, freeing the striker mechanism.  Functioning after this is the same as that with Attachments No.1 Mk I.

Suspension: The bombs may be carried in a Small Bomb Container, or from a bomb carrier by a lug on a suspension band.


Explosive Components:
Filling: 1lb Thermite, and 5lb, 4oz Magnesium

IB 250lb Mks I and II (Obsolete)



Overall length (w/o fuze): 61 inches (approx.)
Body length: 34.1 inches

Body diameter: 12 inches
Tail length: 27.2 inches
Tail width: 11.7 inches
Fuel weight: 68 pounds

Total weight: 193 pounds

Fuzing: Nose Fuze No.36 Mk II with Ejector Charge No.2 Mk I
Tail No.: No.1 Mk I
  

Color and markings: Red overall,
two 2-inch black bands separated by a 2-inch bright red band near nose.

Description: The bomb has a cylindrical body with a hemispherical nose and parallel sides.  An ejector-charge container is screwed and cemented into the nose and takes the nose fuze.  The tail consists of a tail cone and a cylindrical strut attached to the cone by four fins.  The after end of the body is closed by a tail plate, which is lightly secured to the body.


Functioning: On impact, the fuze functions and ignites the gunpowder ejection charge, which in turn ignites the incendiary filling and ejects it with the tail and tail plate.


Suspension: The bomb is suspended by a single suspension lug.


Filling: The Bomb Mk I is filled with a phosphorus-rubber-benzene mixture.  The Bomb Mk II is filled with a "sticky flammable liquid."  The ejector charge consists of black powder.

Remarks: This bomb was intended primarily for attacking forested areas, and can be dropped from heights up to 8,000 feet.

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