American Projectiles and Explosives - Army Experimental Types, and Introduction for Chemical, Incendiary, and Smoke Bombs

American Projectiles and Explosives



Explosive Bombs

Army Experimental Types

4,000-pound G.P. T8

Overall length: 119 inches

Body length: 85 inches
Body diameter: 28 inches
Wall thickness: 0.875 inches

Explosive weight (TNT): 1,856.3 pounds
Explosive weight (Tritonal): 2,002.2 pounds

Total weight: 4,030 pounds

General: This is a design for a 4,000-pound G.P. bomb of the same general construction as others in this class.

Suspension: Standard lugs 30 inches apart.


Filling: Tritonal or TNT with a larger booster, the T21, which is like the M115 except for its increased size.

12,000-pound G.P. T10

Overall length: 21 feet

Body length: 10.33 feet
Body diameter: 3.17 feet
Wall thickness: 1.25 inches

Tail length: 11 feet
Tail width: 3.75 feet
Tail weight: 175 pounds

Filling: Torpex
Weight of filling: 4,980 pounds
Total weight: 11,630 pounds

Charge/weight ratio: 42%

or 

Filling: Tritonal
Weight of filling: 5,500 pounds
Total weight: 12,448 pounds

Charge/weight ratio: 44%

Body construction: The body is manufactured in two different ways.  The British-produced model is of cast steel, with a solid nose plug and with three exploders fitted 120 degrees apart in the tail.  The bomb bodies are issued with exploders inserted, and the exploder tubes are sealed with shipping plugs.  The eventual American T10 will consist of five sections welded together.  These sections are solid nose forging, two body forgings, a rolled plate body section, and a base ring forging.  The base plate, which is a forging, is held to the base ring by means of 20 studs.

The tail is attached to the after end of the bomb body by 12 studs.  A cylindrical metal cowling, placed between the bomb body and the tail cone, enhances the streamlining of the bomb.

Tail construction: The special Tail Unit, No 78 Mk I is constructed of light alloy and consists of a cone to which are attached four fins of streamline cross-section.  The fins are set at an angle of 5 degrees to the axis of the tail cone, giving a slight right-hand spin to the bomb as it falls.  The tail fits over twelve 7/16 inch studs fitted into the bomb body, and is securely fastened to the studs by Simmonds nuts.  Three hand-holes in the tail cone give ready access to the three tail pistols, and an additional hole is provided for arming wires.


Suspension: The bomb is suspended int he plane by twin suspension slings.


Filling: The bomb body contains an explosive filling of Torpex with a one-inch layer of TNT topping added to the after end.  Four inches of woodmeal/wax composition is then added, and the filling sealed with a 1/2-inch plyboard washer.  The three exploders pass through holes in this washer and are held in place by a heavy base plate, which is secured by bolts tot he bomb body.

The American bomb will be filled with Tritonal, with an inert tail surround.


Remarks: This bomb is designed for limited operation use, and its employment will be restricted to specially adapter very heavy bombers.  Although designated a G.P. bomb, the T10 is essentially a deep-penetration bomb (though not armor- or concrete-piercing) depending for its effect upon the production of heavy shock waves as a result of the explosion of its main charge deep within the earth.

The T10 is the american designation for the British 12,000 D.P. (Deep Penetration) "Tallboy" bomb.  Except for size and fuze pocket arrangement, it is similar to the 22,000-pound G.P. Bomb T14.

22,000-pound G.P. T14

Overall length: 25.41 feet

Body length: 12.5 feet
Body diameter: 3.83 feet
Wall thickness: 1.75 inches

Tail length: 13.33 feet
Tail width: 4.48 feet
Tail weight: 287 pounds

Filling: Torpex
Weight of filling: 9,200 pounds
Total weight: 21,875 pounds

Charge/weight ratio: 42%

or 

Filling: Tritonal
Weight of filling: 9,605 pounds
Total weight: 22,155 pounds

Charge/weight ratio: 43%

Body construction: The body is manufactured in two different ways.  The British-produced model is of cast steel, with a solid nose plug and with three exploders fitted 120 degrees apart in the tail.  The bomb bodies are issued with exploders inserted, and the exploder tubes are sealed with shipping plugs.  The eventual American T14 will consist of five sections welded together.  These sections are solid nose forging, two body forgings, a rolled plate body section, and a base ring forging.  The base plate, which is a forging, is held to the base ring by means of 20 studs.

The tail is attached to the after end of the bomb body by 12 studs.  A cylindrical metal cowling, placed between the bomb body and the tail cone, enhances the streamlining of the bomb.

Tail construction: The special Tail Unit, No 82 Mk I is constructed of light alloy and consists of a cone to which are attached four fins of streamline cross-section.  The fins are set at an angle of 5 degrees to the axis of the tail cone, giving a slight right-hand spin to the bomb as it falls.  The tail fits over twelve 7/16 inch studs fitted into the bomb body, and is securely fastened to the studs by Simmonds nuts.  Three hand-holes in the tail cone give ready access to the three tail pistols, and an additional hole is provided for arming wires.


Suspension: The bomb is suspended int he plane by twin suspension slings.


Filling: The bomb contains an explosive filling of Torpex with a one-inch layer of TNT topping added to the after end.  Four inches of woodmeal/wax composition is then added, and the filling sealed with a 1/2-inch plyboard washer.  The three exploders pass through holes in this washer and are held in place by a heavy base plate, which is secured by bolts tot he bomb body.

The American bomb will be filled with Tritonal, with an inert tail surround.


Remarks: This bomb is designed for limited operation use, and its employment will be restricted to specially adapter very heavy bombers.  Although designated a G.P. bomb, the T14 is essentially a deep-penetration bomb (though not armor- or concrete-piercing) depending for its effect upon the production of heavy shock waves as a result of the explosion of its main charge deep within the earth.

The general arrangement of this bomb is identical to that of the 12,000-pound Bomb T40.  The two bombs are identical, except that the T14 has three in-line fuze pockets instead of pockets placed 120 degrees apart as in the T10, and the T14 is an enlarged version of the T10.

The T14 is the American designation for the British 22,000-pound D.P. "Grand Slam" bomb.








Chemical, Incendiary, and Smoke Bombs




Chemical

In general, the chemical bombs are of two types, classified according to case construction.  The light-case bombs have the advantage of higher charge/weight ratio, whereas the heavy-case bombs have better stowage and handling characteristics.  Both types have full-length burster charges to split the bomb case and disperse the filling over the area to be contaminated.  Fuzing must always be instantaneous or aerial burst to maintain maximum dispersion of contents.  Various fillings can be employed for different effects.




Incendiaries

Incendiaries in use at the present time are classified by their construction and use into two types.  The intensive type burns as a unit, confining its intense heat to a relatively small area.  The bombs are small in size and are always dropped in clusters to give area coverage.  They are normally employed against targets having a high percentage of roof coverage, such as industrial establishments and crowded residential areas.  Since the bombs have heavy nose plugs and substantial case strength, some penetration can be expected, and the high burning temperature of the filling will be effective in industrial areas.

The scatter type is usually a larger bomb which disperses small chunks of its burning material over a large area to ignite many small fires.  It is normally employed against readily inflammable targets such as frame construction, material storage, and grain fields.  These bombs explode on impact, to throw burning fragments of gasoline gel or other sticky emulsions against the target.




Screening Smokes

Only the screening smokes will be considered in this chapter, signalling and illuminating smokes being treated under Pyrotechnics.  This division follows in large part the allocation of responsibility for smoke munitions made between the Chemical Warfare Service and the Ordnance Department of the Army.  C.W.S. supervises matters relating to screening smokes, and the Ordnance Department performs the same functions for signalling and illuminating items.



Colors and Markings

Chemical bombs have different markings from other types of ordnance.  The bomb body is painted light grey, and colored bands indicate the nature of the filling.  The bands are located between the dual suspension lugs and before the center of gravity.  One band indicates a non-persistent filler.  Two bands indicate a persistent filler.  Green indicates casualty agents; red, harassing agents; yellow, smoke or screening agents; purple, incendiaries.

Incendiary bombs may follow the scheme of chemical bombs, with light grey body color and a purple band.  More recently, an olive drab body color with a purple band has been standardized.

All these items represent a different type of hazard from high-explosive-filled bombs.  They are particularly susceptible to fire, and proper precautions should be observed.  In handling several of the pyrotechnics and incendiaries, remember to avoid friction such as would be caused by rolling or dragging the missile.



Suspension

Heavy-case chemical bombs are suspended int he same manner as G.P. bombs; that is, by dual suspension lugs or by a single lug welded to the bomb case.  The light-case chemical bombs are suspended by lugs welded to bands which fit around the bomb body.  Incendiary bombs of the large scatter type have the same suspension as the chemical bombs.  The smaller incendiary bombs are always clustered, and for maximum packing efficiency are hexagonal in shape.  The clusters employed on incendiaries are of two types, the quick-opening variety and the aimable type with a cluster opening controlled by an aerial burst fuze.  The quick-opening clusters come in two sizes - 100-pounds and 500-pounds.  The cluster adapters for 4-pound intensive incendiaries will carry 84 bombs in the 100-pound size or 128 bombs in the 500-pound size.  The adapters for 6-pound scatter incendiaries carry 14 bombs or 60 bombs.  The cluster adapters consist of steel tubes supported by plates, with the bombs assembled around the tubes.  The bombs are held in place by spring-steel bands secured by an arming wire running through a buckle at the end of the band.  Removal of the arming wire assembly as the cluster drops releases the buckles, and the bands open to release the bombs immediately.

The aimable clusters are relatively new.  They fit a 500-pound bomb station and are designed for precision bombing from high altitudes.  To give the cluster the desired ballistic properties, a standard box-type tail assembly is attached by a single bolt to the after plate of the cluster adapter.  A strip of primacord (PETN) running full-length along the side of the cluster serves to break the spring steel bands and allow the bombs to scatter when the aerial-burst nose fuze functions.  The 500-pound Aimable Cluster AN-M17A1 is filled with 110 4-pound Incendiary Bombs AN-M50A2 and AN-M50XA3.  The Cluster Adapter E6R2 (500-pound) contains Incendiary Bombs AN-M69 or M74.  The Aimable Cluster Adapter M23 (500-pound) contains 38 bombs, either Incendiary Bomb AN-M69, Incendiary Bomb M74, or Smoke Bomb M77.




Jettisonalbe fuel tanks "Fire Bombs"

Fuel tanks filled with a gasoline-Napalm mixture for incendiary purposes and fitted with igniters were developed during the war.  At present, however, the practice has been discontinued.

Next Time: Chemical, Incendiary, Smoke - "M" Series Bombs

American Projectiles and Explosives - Explosive Bombs - "AN" Series (Part 3)

American Projectiles and Explosives



Explosive Bombs

"AN" Series

A.P. AN-Mk 33 (1,000-pound) and AN-Mk 1 (1,600-pound)

AN-Mk 33

Overall length: 73 inches
Body length: 58 inches
Body diameter: 12 inches
Tail length: 17 inches
Tail width: 16 inches

Filling: Explosive D, Cast TNT
Weight of filling: 140 pounds
Total weight: 1,025 pounds
Charge/weight ratio: 14%

AN-Mk 1

Overall length: 83.5 inches
Body length: 69.5 inches
Body diameter: 14 inches
Wall thickness: 1.3 inches
Tail length: 20.5 inches
Tail width: 20.6 inches

Filling: Explosive D, Cast TNT
Weight of filling: 215 pounds
Total weight: 1,590 pounds
Charge/weight ratio: 14%



Construction: The bodies are of single-piece, forged, machined construction, with pointed noses, parallel sides, and alight boat tailing.  The base plate is of the male type.  Suspension in the 1,600-pound A.P. Bomb Mk 1 design was by means of lugs welded to bands, the bands being positioned by grooves on the external bomb surface.  The newer designs, AN-Mk 1 and Mk 33, are suspended by fittings which screw into holes drilled into the bomb case and secured by bolts.  The normal box-type tail assembly is used on these bombs.


Filling: The main filling of these bombs is pressed Explosive "D" or cast TNT.  The tail fuze pocket requires use of the granular TNT Auxiliary Booster Mk 1.


Remarks: The later 1,600-pound A.P. Bombs Mk 1 Type were grooved to position the suspension band.  Older bombs had a stud which fitted into a hole in the bomb body.







325-, 350-pound Depth Mk 17 (TNT - Obsolete), Mk 17 Mod 1 (TNT), AN-Mk 17 Mod 2 (TNT), AN-Mk 44 (Torpex), AN-Mk 41 (TNT), and AN-Mk 47 (Torpex)

AN-Mk 17 Mod 2; AN-Mk 44

Overall length: 52.5 inches
Body length: 31.1 inches
Body diameter: 15 inches
Wall thickness: 0.06 inches
Tail length: 20.2 inches
Tail width: 20.6 inches

AN-Mk 41; AN-Mk 47

Overall length: 49.9 inches
Body length: 27.8 inches
Body diameter: 15 inches
Wall thickness: 0.06 inches
Tail length: 24.6 inches
Tail width: 15.4 inches


AN-Mk 17 Mod 2
Filling: TNT
Weight of filling: 224 pounds
Total weight: 325 pounds
Charge/weight ratio: 68.9%


AN-Mk 44
Filling: Torpex
Weight of filling: 249 pounds
Total weight: 350 pounds
Charge/weight ratio: 71.1%


AN-Mk 41
Filling: TNT
Weight of filling: 227 pounds
Total weight: 347 pounds
Charge/weight ratio: 65.4%


AN-Mk 47
Filling: Torpex
Weight of filling: 252 pounds
Total weight: 355 pounds
Charge/weight ratio: 70.9%

Nose construction: Depth Bombs AN-Mk 17 Mod 2 and AN-Mk 44 have round noses, and can use the flat-nose attachment; AN-Mk 41 and AN-Mk 47 are flat-nosed.


Body construction:
-AN-Mk 17 Mod 2 and AN-Mk 44: These depth bombs are made with round noses welded to a cylindrical steel tube.  There is a strengthening disc around the nose and a steel strip along the suspension lugs to reinforce the body.  The transverse fuze pocket is 11.9 inches abaft the nose.  To prevent ricochet and improve underwater trajectory, a flat-nose attachment is made for these bombs, the attachment being in the shape of a bucket which fits down over the nose and is filled with plaster of paris, increasing the weight of the bomb by 44 pounds.  The bomb case is extremely thin.

-AN-Mk 41 and AN-Mk 47: These bombs are constructed with a flat nose, there being a slight taper from the walls to the nose.  The body is in three pieces.  The sides are tubular with a transverse fuze pocket tube welded in place 15 inches abaft the nose.


Suspension: Suspension of these bombs is by the usual dual or single lugs, the lugs being welded to the bomb.  The single lug is actually somewhat different than is usually found, being in the form of a bracket rather than a lug.  Trunnions on a band are for displacement gear in dive bombing.


Tail construction: Instead of employing the box-type tail, these bombs use a drum tail.  As seen from the after end, it is circular and has four fins extending at right angles to each other.  The fins are spot-welded to a cone which fits over the after end of the bomb.  The fins are also spot-welded to the drum shroud.  The tail is bolted onto the base of the bomb.


Markings: TNT-loaded bombs have weight and Mark number stencilled in yellow; Torpex-loaded bombs have these items stencilled in blue.


Remarks: The 325-pound Depth Bomb Mk 17 is TNT-loaded but has a light tail assembly; the Mk 17 Mod 1 is the same, except that a sturdier tail assembly is used.  The AN-Mk 17 Mod 2 is similar to the Mod 1, but has a larger filling hole.

The Mk 17 is obsolete; the Mk 17 Mod 1, AN-Mk 17 Mod 2, AN-Mk 44, AN-Mk 47, and AN-Mk 41 are obsolescent.








325-, 350-pound Depth AN-Mk 53 Mod 1 (TNT),  AN-Mk 54 Mod 1 (HBX), Mk 53 (TNT), and Mk 54 (Torpex)

Overall length: 52.5 inches
Body length: 33.25 inches
Body diameter: 13.8 inches
Wall thickness: 0.06 inches
Tail length: 24.5 inches
Tail width: 13.9 inches


AN-Mk 53 Mod 1; Mk 53
Filling: TNT
Weight of filling: 225 pounds
Total weight: 330 pounds
Charge/weight ratio: 68%


Mk 54
Filling: Torpex
Weight of filling: 250 pounds
Total weight: 354 pounds
Charge/weight ratio: 70.6%


AN-Mk 54 Mod 1
Filling: HBX
Weight of filling: 250 pounds
Total weight: 354 pounds
Charge/weight ratio: 70%



Body construction: The cylindrical welded sheet-steel body has a flat nose.  A base closing plate is secured to the rear of the bomb by four bolts.  A base closing plate is secured to the rear of the bomb by four bolts.


Suspension: These bombs are suspended horizontally by two lugs seven inches on each side of the center of gravity, or by a single lug at the center of gravity and 180 degrees removed from the other lugs.  There is no external band, the bombs being strengthened internally by a band which is fitted into the bomb at the center of gravity.  Trunnions for dive bombing may be threaded to the case and internal strengthening band.


Tail construction: Welded to the tail cone are four vanes which are strengthened by interior box-type struts, and an exterior wide ring strut.  The tail cone is secured to the base closing plate by four bolts.


Markings: Olive drab overall.  "Mk 53 - 325 lb. Depth Bomb", "Mk 54 - 350 lb Depth Bomb" stencilled on the respective bomb bodies in yellow if the filling is TNT, or in blue if the filling is Torpex.


Remarks: These two bombs (identical except for filling) have been designed to replace depth bombs using athwartship fuzes, since difficulties have been encountered at times in the past with the Athwartship Fuzes AN-Mk 224 and AN-Mk 234.  The Depth Bombs Mk 53 and Mk 54 will use the Tail Hydrostatic Fuze AN-Mk 230 and a nose fuze, having no athwartship pocket.

The Depth Bombs AN-Mk 53 Mod 1 and AN-Mk 54 Mod 1 differ from the Depth Bombs Mk 53 and Mk 54 respectively in that the suspension lugs are welded on, instead of being of the screw type.  In addition, the walls of the explosive cavity of the two bombs are coated with an asphaltic composition known as Hot Melt.  The AN-Mk 54 Mod 1 is loaded with HBX rather than Torpex.

Only the modifications of the Depth Bombs Mk 53 and Mk 54 have been standardized as AN bombs.











1,000-pound Aircraft Mine AN-Mk 26 Mod 1 (Ground, Influence-Fired)

Overall length (w/ parachute pack): 68.5 inches
Overall length (w/o parachute pack): 64.5 inches

Diameter:
-Case: 18.625 inches
-Tail section: 15.75 inches
-Parachute pack: 18.5 inches

Filling: TNT
Weight of filling: 465 pounds
Total weight: 1,000 pounds
Charge/weight ratio: 46.5%
Negative buoyancy: 400 pounds

or

Filling: Torpex
 Weight of filling: 525 pounds
Total weight: 1,060 pounds
Charge/weight ratio: 49.5%
Negative buoyancy: 460 pounds


Construction: The 1,000-pound Aircraft Mine AN-Mk 26 Mod 1 consists of a cylindrical steel case welded with hemispherical nose and tapered tail section.  The tail is closed by a concave cover secured with cap screws.  A ring for mounting the parachute assembly is welded around the after end of the case.  The Tail Parachute Pack Mk 1, containing Parachute Mk 2, is fitted to the tail when the mine is installed in plane.  This parachute slows the fall of the mine through the air to lessen the shock of water impact, and is released from the case on striking water by an impact release mechanism.  Suspension is horizontal, two standard lugs being welded onto the body 14 inches apart and placed 90 degrees from the side pockets.

There is a removable British single-suspension lug 180 degrees removed.


Markings: Black overall


Remarks:
-Normal Use: As ground, magnetic induction mine.  Aircraft-laid, with parachute (release altitude - 200 feet or higher).  Laid offensively in depths of water from 16 feet to 120 feet against surface craft, and up to 500 feet against submarines.  Extender and clock starter are caused to function by hydrostatic pressure at depths of 16 feet or greater.  Clock delay runs off in 170 minutes to arm the mine.

-Use as bomb: This mine is poorly suited for use as a bomb, since accurate dropping by parachute is difficult; and if parachute is not used, the case tumbles.  Fuzes require longer air travel to arm than usual, because of the shape of the mine and the manner of fall through the air.






20-pound Frag. AN-M41, and AN-M41A1

Overall length: 19.5 inches
Body length: 11.3 inches
Body diameter: 3.6 inches
Wall thickness: 0.56 inches
Tail length: 9.26 inches
Tail width: 5.1 inches
Tail weight: 1.6 pounds

Filling: TNT
Weight of filling: 2.7 pounds
Total weight: 20.3 pounds
Charge/weight ratio: 13%



Body construction: This bomb is constructed of cast-steel nose and tail pieces, a seamless steel inner tube, and a helically-wrapped drawn steel wire wrapping around the inner tube.  The tube is threaded to hold the nose and tail sections.


Suspension: For individual suspension of this bomb, a U-shaped eyebolt of steel is welded to the body at the center of gravity for horizontal suspension, and an eyebolt is welded to the tail for vertical suspension.

The bomb may be dropped in a cluster of six bombs in the Cluster Adapter AN-M1A2 or M1, forming the Cluster AN-M1A1 or M1.  The cluster adapter is made of sheet steel, and does not use eyebolts of bombs for suspension.


Tail construction: Four rectangular sheet-steel vanes are welded to a length of one-inch cast-iron pipe which screws into the base filling plug.


Remarks: This bomb is a high-level fragmentation bomb and should be dropped from a minimum altitude of 400 feet.

The A1 modification of this bomb consists of adding a 1 and 1/2-inch shoulder around the nose to facilitate clustering with unfuzed bombs.  Heretofore, the spacers of the cluster adapter have fitted against the fuze, thereby making it requisite that the bombs be clustered and shipped with fuzes inserted.








23-pound Para-Frag. AN-M40, AN-M40A1, M72, and M72A1

Overall length: 26.7 inches
Body length: 11.3 inches
Body diameter: 3.6 inches
Wall thickness: 0.56 inches
Tail length: 13.9 inches
Tail width: 4.35 inches
Tail weight: 5.3 pounds

Filling: TNT
Weight of filling: 2.7 pounds
Total weight: 24.5 pounds
Charge/weight ratio: 11%



Body construction: These bombs are constructed of cast-steel nose and tail pieces, a seamless steel inner tube, and a helically-wrapped drawn steel wire wrapping around the inner tube.  The tube is threaded to hold the nose and tail sections.


Suspension: For individual suspension of these bombs, a U-shaped eyebolt of steel is welded to bomb at the center of gravity.

The 23-pound Para.-Frag. Bombs AN-M40 are always clustered, three of the bombs with the Cluster Adapter AN-M3 forming the Cluster AN-M4.

The 23-pound Para.-Frag. Bomb M72 is a slightly modified version of the AN-M40.  It is adapter for individual suspension and can be carried in vertical cellular racks by several types of Army planes.


Tail construction: The 23-pound Para.-Frag. Bombs AN-M40 and M72 are fitted with cylindrical sheet-steel parachute housings which have end caps at the rear end and contain a white silk parachute.  The Parachute Unit M3 is used in the Para.-Frag. Bombs AN-M40 and AN-M40A1; the Parachute Unit M4 in the Para.-Frag. Bombs M72 and M72A1.


Remarks:  The AN-M40 and M72 are low-level fragmentation bombs and should be dropped from a maximum altitude of 400 feet.


The A1 modification of these bombs consists of adding 1 and 1/2-inch shoulder around the nose of the bomb to facilitate clustering with unfuzed bombs.  Heretofore, the spacers of the cluster adapters have fitted against the fuze, thereby making it requisite that the bombs be clustered and shipped with the fuzes inserted.  Bombs with this modification are designated the 23-pound Para.-Frag. Bombs AN-M40A1 and M72A1.






Fragmentation clusters and cluster adapters



Cluster AN-M1A1, Cluster Adapter AN-M1A2: This cluster, consisting of the Cluster Adapter AN-M1A2 or M1 and six Fragmentation Bombs AN-M41, is made of sheet metal and does not use eyebolts for suspension.


Cluster AN-M1A2, Cluster Adapter AN-M1A3: With the modification of Fragmentation Bombs AN-M41 to permit fuzing in the field, the following changes are made in the Cluster Adapter AN-M1A2: (1) flat springs are substituted for the fuze lock plates; and (2) the suspension lugs are changed from a strip type to a type similar to those on G.P. bombs.  The new lugs were designed to permit suspension of the clusters in all existing types of bomb racks.  The modified cluster adapter becomes the AN-M1A3, forming, with six Fragmentation Bombs AN-M41A1, the Cluster AN-M1A2.

If the modified Cluster Adapter AN-M1A3 is used with unmodified Fragmentation Bombs is used with modified Fragmentation Bombs AN-M41; or the unmodified Cluster AN-M1A1 is used with modified Fragmentation Bombs AN-M41A1; or the unmodified Cluster Adapter AN-M1A1 is used with unmodified Fragmentation Bombs AN-M41, no change will be made in the designation of the Cluster AN-M1A1.  The bombs, in these latter cases, will be fuzed when the bombs are clustered at the loading plant.

The unmodified Fragmentation Bomb AN-M41 with Cluster Adapter AN-M1A1 is not suitable for Navy use.  The modified Adapter AN-M1A2 can be used, and the cluster is designated S1ZVL.


Cluster AN-M4, Cluster Adapter AN-M3: The cluster Adapter AN-M3 and three Fragmentation Bombs AN-M40 form the Clsuter AN-M4.


Cluster AN-M4A1, Cluster Adapter AN-M3: When Para.-Frag. Bombs AN-M40A1 are clustered, the Cluster Adapter AN-M3 is still used without any alteration in design, but the designation of the cluster is AN-M4A1.


Cluster M26, Cluster Adapter M13: The Fragmentation Bomb Cluster M26 consists of a Cluster Adapter M13 to which are secured twenty 20-pound Fragmentation Bombs AN-M41A1, in two groups of ten.  The cluster is 53 and 1/2-inches long, 14 and 11/16-inches wide, and 13 and 3/4-inches high.  The cluster adapter is a steel framework consisting of a tubular suspension bar to which the suspension lugs are fitted, steel separator plates, and two metal straps secured by release buckles.  The separator plates located before each group of the bombs are built with arming vane stops for the Nose Fuzes M110A1 used in the individual bombs.  The cluster can be adapter for either quick or delayed opening.

Quick opening is accomplished by the arming wires, which are fed through the release buckles and are withdrawn on the release of the cluster from the plane.   In delayed opening, a Mechanism Time Nose Fuze M155 (T71) or M1111A2 is screwed to the fuze adapter in the forward end of the tubular suspension bar.  When the fuze detonates at the preset delay, the explosion drives a steel slug rearward to cut the shear wires in both the forward and the after release buckles, thereby permitting the cluster to open.

Tumbling of the Cluster M26 prevents the Nose Fuze M111A2 from arming correctly, and therefore the fuze has been modified by the substitution of an anemometer-type arming vane for the standard vane.  So modified, the fuze is known as the T77.  Modification can be accomplished in the field by kits now being issued.








220-, 260-pound Frag. AN-M88 (220-lb) and AN-M81 (260-lb)

AN-M81
Overall length: 43.7 inches
Body length: 32.8 inches
Body diameter: 8 inches
Wall thickness: 1 inch
Tail length: 11 inches
Tail width: 11.5 inches
Tail weight: 4.1 pounds

Filling: Composition B
Weight of filling: 34.1 pounds
Total weight: 260 pounds
Charge/Weight ratio: 14%



AN-M88
Overall length: 43.7 inches
Body length: 32.8 inches
Body diameter: 8 inches
Wall thickness: 1.25 inches
Tail length: 11 inches
Tail width: 11.5 inches
Tail weight: 4.1 pounds

Filling: Composition B
Weight of filling: 46.9 pounds
Total weight: 216.17 pounds
Charge/Weight ratio: 21.6%


Construction: The Fragmentation Bomb AN-M88 differs from the M81 only in that it has a 0.75-inch steel coil steel coil around the body instead of the one-inch coil.  Both bombs are constructed in these two ways.  In initial production, nose and tail pieces are of cast-steel construction and screw onto a central section of seamless steel tubing.  A square helical steel spring is wound around the steel tubing.  The nose and tail pieces are partially cut through to afford greater fragmentation (this is similar to the M82, except for the provision for tail fuzes and the Auxiliary Booster M104 in the larger bombs).  The majorite of AN-M88's and M81's however, have a one-piece steel tubing, and the helical steel spring is wound around the steel tubing, for the entire length of the body.

Suspension is horizontal; two eyebolts are welded to body along the longitudinal axis of the bomb, 14 inches apart.  A third eyebolt is welded to the body at the center of gravity 180 degrees removed from the other eyebolts.  The tail is the normal box type, secured to the bomb by a locking ring.


Remarks: The initial bombs were filled with TNT; later productions are filled with Composition B with TNT surrounds.

Present production of these bombs does not include Auxiliary Booster M104, as this was found unnecessary.

Next Time: Army Experimental Types, and Introduction for Chemical, Incendiary, and Smoke Bombs

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)

American Projectiles and Explosives - Explosive Bombs - "AN" Series (Part 1)

American Projectiles and Explosives



Explosive Bombs

"AN" Series

Introduction

The creation of the Army-Navy Standardization Board resulted in the standardization of the bombs of these two services into the AN series.  This series was very similar to the M series except for these modifications:

1. A third suspension lug was added at the center of gravity and diametrically opposite the dual suspension lugs, to fit British release devices.

2. The base plate was changed to a male plug to increase the strength on low-angle penetration of targets.

3. The bombs were painted an overall olive-drab with one-inch yellow bands around the nose and base, and a 1/4-inch yellow band around the center of gravity.

The bombs in this series included the following weights: 100, 250, 500, 1,000, and 2,000 pounds.  These bombs are all general purpose high-explosive bombs.  Thought other types of bombs - armor-piercing, semi-armor-piercing, fragmentation, incendiary, depth, etc. - have been subsequently standardized and given AN designations, it is with the AN general purpose bombs and their modifications that this introduction shall be concerned.

AN G.P. Series: The AN series was subsequently replaced by the AN G.P. series to make it possible for these bombs to be used in anti-submarine work as well as for general bombardment.  This modification was incorporated into the 500-, 1,000-, and 2,000-pound bombs only, their new designations becoming AN-M64, AN-M65, and AN-M66, and consisted of a change from the Adapter Booster M102 to the Adapter Booster M115.  With the Adapter Booster M115, it became possible to use either standard Army tails fuzes or the Tail Hydrostatic Fuze AN-Mk 230.  The standard filling of these bombs was 50/50 Amatol until the supply of TNT became ample in 1943, at which time TNT became the standard filler.  At the present time, 25% of the production of these bombs is filled with Composition "B".

AN G.P. A1 Series: The A1 modification consists of two steel pins in the base plate which lock the base plate to the main filling, thus preventing removal of the base plate, once the bomb is filled.  In this series the adapter boosters have also been modified to the M102A1 and the M115A1.  This modification consists of a hole through the adapter booster and a groove in the threads of the base plate to receive a locking pin which is shipped with all anti-withdrawal tail fuzes.  Insertion of the pin which is held in by the fuze body prevents withdrawal of the adapter booster.  This series is the current production G.P. bomb series and is used jointly by the Army, Navy, and British forces.

Body Construction: The body construction of American G.P. bombs may be in one, two, or three pieces.  Methods of manufacture include (1) one-piece cast or spun, (2) two-piece cast and welded, or (3) three-piece cast and welded.

The ogival nose tapers to join in the thin parallel side walls, which terminate in a boat-tailed shape at the after end.  The threaded nose opening is closed by the fuze-seat liner, and the threaded base opening is closed by a male plug, the tail fuze pocket being made by the adapter booster.

Suspension: Dual suspension lugs for horizontal suspension are welded directly to the bomb case, being spaced 14 inches apart on bombs up to 2,000 pounds, and 30 inches apart on bombs 2,000 pounds and over.  A single horizontal suspension lug is also welded to the bomb case at the center of gravity and diametrically opposite the dual lugs.  The lugs are eyebolts, shaped from bar steel and formed in the shape of a "U".  "M" series bombs could be carried on single suspension racks by using an additional single-suspension lug welded on a band fitting around the bomb body at the center of gravity.

For suspension in dive-bomb displacement gear, trunnions are provided on a separate band which may be one of two types.  The first type provides the trunnion only; and the second, a more common type, provides a single hoisting lug in addition to the trunnions.  On some of the newer designs of AN bombs of Navy manufacture, the suspension and hoisting fittings are not attached to the bomb case by welding, but are held to the case by threaded bolts fitting into holes tapped and threaded into the body.  For suspension in torpedo slings, the torpedo sling guide key found on Navy bombs can be made on AN bombs by using the base of the single suspension lug with the lug removed by gentle hacksawing.

To hoist bombs into Navy planes, the AN bombs not equipped with hoisting lugs must have a hoisting lug furnished by either an expendable band with single or dual lugs, or by a removable hoisting band.  The removable band is preferred, since it does not affect the terminal velocity of the bomb.  The newest and best of theses bands is the Universal Hoisting Band Mk 8.  For Army planes, bombs are usually hoisted by canvas slings, which also have the advantage of not affecting air trajectory.

Tail fin construction: The tail construction is known as the box-type tail and consists of the following parts: a cast-steel sleeve secured to the body of the bomb by a fin locking nut, and four sheet-steel supported by four sheet-steel struts in the shape of a box.  One fin and one strut are pressed from a single piece of metal, and the four pieces are then welded to the sleeve.  "A" indicates heavier construction for high-altitude bombing.

Color and markings: The standard color scheme employed on these bombs since 11 March 1942 has been olive drab body with yellow bands to indicate the H.E. filler.  The banding system for Amatol and TNT fillers is a one-inch yellow band at the nose, a one-inch yellow band at the tail of the bomb body, and a 1/4-inch dotted band at the center of gravity.  Because Composition "B" is more sensitive and requires more careful handling, it is given an additional marking consisting of a second one-inch yellow band at the nose and at the tail.  On these bands "Comp. B" is stenciled in black paint.  Recent production eliminates the 1/4-inch band, since the center of gravity is located accurately enough by the single suspension lug.

The following standard markings are painted on the bomb body in black paint: type, weight, and name of bomb, type of filling, lot number, place and date of filling, and inspector's initials.

Additional indestructible marking is stamped into the metal of the bomb case on the rear conical surface of the bomb body: type, size, name, maker's initials, lot number, and date. 

(IE: G.P. 500 lb. AN-M64 CSCO Lot 57 4/42)

Explosive filling: The filling of these bombs is accomplished in the following manner.  With the nose-fuze seat liner in place, the bomb is placed on end nose-down and an Auxiliary Booster M104 is positioned behind it.  The M104 is a bakelite tube containing tetryl pellets.  The initial pour of the explosive is sufficient to secure the auxiliary booster when it cools.  Then the remainder of the filling, 50/50 Amatol, TNT, or Composition "B", is added until a depth of approximately six inches remains to be filled.  A second Auxiliary Booster M104 is then inserted in all bombs except the 100-pound, and the tail surround is added to complete the filling.  A wooden former is inserted in the tail-fuze cavity as the filling cools.  After cooling, the former is removed and the appropriate adapter booster is inserted.  The adapter booster consists of the fuze-seat liner with an additional steel cup containing a tetryl pellet.  The Adapter Booster M102 (and M102A1) has an internal thread diameter of 1.5 inches.  The adapter Booster M115 has an internal thread diameter of 2 inches, and an adapter ring for further reduction of the diameter to 1.5 inches when smaller fuzes are used.

Tests conducted by the Army indicated that the presence or absence of Auxiliary Boosters M104 does not alter the effectiveness of the detonation of bombs.  On the basis of these tests, the Army started to eliminate the Auxiliary Booster M104 from Composition "B" loaded 500-pound, 1,000-pound, and 2,000-pound G.P. bombs during the latter part of 1944.  Elimination of Auxiliary Boosters M104 in TNT and Tritonal loaded G.P. and S.A.P. bombs was started in March (TNT) and June (Tritonal) of 1945.  At the present time, all productions of Composition "B", TNT and Tritonal loaded G.P. and S.A.P. bombs, and Composition "B" loaded Frag. bombs, exclude Auxiliary Boosters M104.


The bombs from which the Auxiliary Boosters M104 are now eliminated are as follows:

Tests conducted by the Army have shown that inert nose and tail surrounds improve safety in handling of G.P. and S.A.P. bombs.  On the basis of these tests, the majority of G.P. and S.A.P. bombs loaded at the present time have inert nose and tail surrounds.  This covers Composition "B", TNT, Tritonal, and Picratol filled bombs.  Formerly Composition "B" loaded bombs had TNT surrounds.

The ingredients of the inert surrounds used at present are as follows:

Ester gum, 51%
Castor oil, 10.5%
Kaolin, 34.5%
Wax, Hydrocarbon, 4%


The thickness of these surrounds is as follows:

The thickness of the surrounds is such that most, if not all, of the explosive portion of the adapter booster and that of the nose-fuze booster (surrounded by fuze seat liner) extends into the main filler, with exception of the S.A.P. nose setup.



Anti-Ricochet attachments: To give a more nearly vertical impact to 100-pound, 250-pound, and 500-pound G.P. bombs and to break their rapid descent when dropped from low-flying planes, the Anti-Ricochet Devices M16 and M17 have been developed.  The device consists of a parachute unit, a modified AN-M112A1 series tail fuze (M151) using an anemometer-type arming vane, and a fuze adapter.

Cluster and cluster adapters: Properly, the cluster adapter is merely the containing device or holder.  When the adapter is loaded with bombs, the entire assembly becomes a cluster.  In some cases the cluster adapter may closely resemble a bomb in construction (e.g. M15 and M16), while in others the adapter is nothing more than a banding arrangement (AN-M1A1, AN-M4).

Next Time:"AN" Series (Part 2)