Monday, 24 September 2018

American Projectiles and Explosives - Chemical, Incendiary, Smoke - "MK" Series Bombs





American Projectiles and Explosives



Explosive Bombs



"MK" Series




100-pound Incendiary Mk I and Mk 28 (Obsolete)


Overall length: 45.5 inches
Body length: 33.7 inches
Body diameter: 8 inches
Wall thickness: 0.05 inches
Tail length: 11.75 inches
Tail width: 11.3 inches

Filling: Gasoline, Gasoline-Gel, Gasoline and Waste, rubber

Weight of filling: 42 to 45 pounds
Total weight: 65 to 68 pounds
Charge/weight ratio: 65% (approx.)


Construction: The bomb is of three-piece sheet-steel construction, with a hemispherical nose piece and aconical tail cone welded to a tubular body.  The bomb has two suspension lugs on bands or a single lug on a band near the center of gravity.  The tail assembly consists of four sheet-steel vane welded to the tail cone, which, in turn, is welded to the body.



Color: The bomb is painted grey overall, with a bright red disc, four inches in diameter, in the middle of the body.


Remarks: This bomb is similar to the 100-pound Incendiary Bomb AN-M47A2, except that it is equipped with a filler cap.  Both bombs are prone to leak and should be examined frequently.

There is also a 100-pound Incendiary Bomb Mk I, which is almost identical to the old Army M47, both of which are obsolete.






100-pound Chemical Mk 42

For photo, see above

Overall length: 39.43 inches
Body length: 27.7 inches
Body diameter: 8 inches
Wall thickness: 0.17 inches
Tail length: 9.46 inches
Tail width: 11 inches

Filling: Mustard gas

Weight of filling: 43 pounds
Total weight: 86.5 pounds
Charge/weight ratio: 50%


Construction: The steel tube is swaged aft.  An adapter screws into the nose and is threaded to receive the fuze.  A burster tube containing TNT, running the length of the bomb, screws into the after end of the adapter.  The after end of the body is closed by a male base plate, which is threaded for the tail assembly to be fitted.  The bomb is filled through the nose.  Suspension is by two lugs seven inches on either side of the center of gravity or a single lug 180 degrees removed and at the center of gravity.  The bomb has a box-type, four-fin tail, secured by a locking nut.


Markings: The bomb is painted olive drab overall, with two green bands 1/2 inch wide and 1/2 inch apart abaft the nose.






50-, 100-pound Floating Smoke (Obsolescent) Mk 3 Mod 0 (100-lb), Mk 1 Mod 1 (50-lb), Mk 1 Mod 2 (50-lb)

For photo, see top

Mk 3 Mod 0
Overall length: 48.5 inches
Body diameter: 10.25 inches
Tail length: 13 inches
Tail width: 14.25 inches
Filling: HC Mixture
Weight of filling: 59 pounds
Total weight: 102 pounds
Charge/weight ratio: 57.8%


Mk 1 Mod 2
Overall length: 38.29 inches
Body diameter: 8.85 inches
Tail length: 9.4 inches
Tail width: 8.94 inches
Filling: HC Mixture
Weight of filling: 28 pounds
Total weight: 54 pounds
Charge/weight ratio: 51.8%


Construction: An aluminum nose casting, carrying a pyrotechnic charge, is attached to a hollow wood float which provides buoyancy.  The nose carries a water-impact fuze, and at the tail of the float is a valve cap with the valve to prevent water from leaking into the interior of the bomb.  The rear of the bomb is conical in shape, and the aluminum nose is hemispherical.  The tail consists of four fins bolted to the rear of the bomb, with four tubular struts bolted to the fins.  The fins do no extend upon the rear end of the bomb.


Suspension
: Two movable suspension bands are used on the Floating Smoke Bomb Mk 3 Mod 0; the Mk 1 Mods 1 and 2 may have either one or two suspension bands.  The latest issue has one band and one attached lug, so that the bombs may be suspended from the single- and double-hook racks.


Action: Impact operates the firing mechanism in the nose, detonating the primer, which in turn ignites a length of time fuze giving a delay of 18 seconds, during which time the smoke bomb is returning to and becoming stable on the surface of the water.  The time fuse ignites the quick match which, in turn, ignites the starting mixture and this initiates the action of the smoke mixture.  Gas pressure formed by the burning smoke mixture breaks the vent discs and opens the valve cap at the tail end of the wooden float.  The bomb then evolves a dense white smoke for about 7.5 minutes in the Mk 3 Mod 0; 2.5 to 5 minutes in the Mk 1 Mod 1 and 5 to 7.5 minutes in the Mk 1 Mod 2.


Remarks: This bomb should be dropped from an altitude of over 500 feet and should not be dropped in less than 40 feet of water where the bottom is soft enough to cause the bomb to stick and fail to return to the surface.  While designed for use over water, the bomb may also be effective if dropped over ordinary loam soil, if dropped from an altitude under 2,000 feet.  If dropped from over 2,000 feet or if dropped from any altitude onto very hard rocky ground, the bomb will usually deflagrate.  The HC mixture is a pressed powder, safe under any normal storage or handling conditions.  The smoke, while harmless in the concentration found in smoke screens in the open, is toxic in more concentrated form.

The 50-pound Floating Smoke Bomb Mk 1 Mod 2 differs from the Mod 1 in that it has a longer burning time, with a maximum of 7.5 minutes, as in the 100-pound Mk 3 Mod 0, and a minimum of 5 minutes.





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

Monday, 10 September 2018

American Projectiles and Explosives - Chemical, Incendiary, Smoke - "M" Series Bombs





American Projectiles and Explosives



Explosive Bombs



"M" Series




10-pound Incendiary M74


Overall length: 19.4 inches
Body length: 19.4 inches
Body diameter: 3 inches
Tail length: 6.3 inches
Tail width: 2.5 inches
Filling: PT 1 or NP


Construction: This bomb has the same type of construction as the 6-pound Oil Incendiary Bomb AN-M69, with a sheet-steel leak-proof casing and a nose cup housing the fuze.  A small chemical container, located immediately behind the dome of the nose cup, is filled with white phosphorus, to aid ignition of the incendiary composition and produce smoke.  In bombs with NP, the filling is enclosed in a cheesecloth sock; if PT 1 is used, it is loaded directly into the bomb.  The Incendiary Bomb M74 has a telescope-type tail which fits inside the tail cup and is ejected under spring pressure when the bomb is released from the cluster.  A well inside the tail cup holds the tail sleeve when the assembly is compressed in the cup.




Operation: The striker of the Fuze M142 or M142A1 ignites the primer, which sets off the booster and main ejection charge.  This activates the auxiliary ejection-ignition charge.  Expanding vases rupture the dome-shaped ejection diaphragm, which forces the WP-filled cup, incendiary filling, tail cup, and tail assembly out of the bomb casing.


Remarks: Do not reinsert arming pin after it has been ejected, as it may cause the fuze to function.

The experimental bombs of this type with other fillings are designated the E5 series.  The experimental bomb with a white phosphorus filling has been rejected; however, the one with the mustard filling, E5R8, is still under development.  This bomb will be carried int he Cluster E61 holding 38 bombs (Cluster Adapter M23).




Cluster Adapter E6R2


Overall length: 59.06 inches
Body diameter: 14.69 inches
Tail width: 16 to 18 inches


General: The cluster adapter has a thin steel body that is shaped like a bomb, except the nose is not rounded off to make a full hemisphere.  A standard-type bomb fin is affixed to the rear of the adapter, and a fuze fits in the nose.  Hoisting and suspension lugs are located at the top.  Internally, the adapter is equipped with cluster bars for positioning of the bombs when loaded.  An L-shaped angle bar runs the entire length of the adapter along the bottom cluster bar.  Into the angle bar is fitted a light steel tube which encloses a length of primacord that extends from the nose fuze to the other end of the cluster adapter.  When the cluster is filled, the bomb are packed nose-forward, 19 in the front half of the adapter and 19 in the after portion.  The assembly is held together by nine nailless steel straps.  The cluster adapter then becomes a 500-pound aimable cluster that will fit any 500-pound bomb station, and, when dropped from high altitude, approximates the trajectory of a 100-pound demolition bomb.




Operation: On release, the arming wire is pulled, allowing the clockwork to start and the vanes to turn.  When the vanes have made the proper number of turns, a striker-pin safety block falls out, completely arming the fuze, so that it functions upon expiration of the predetermined time setting.  Firing of the fuze detonates the primacord, which runs the full length of the adapter.  Explosion of the primacord breaks the nine nailless steel straps, allowing the cluster adapter wall to open and the bombs to scatter.


Remarks: If desired, the cluster adapter may be kept intact during the entire period of flight, bursting open on impact.

This adapter is being replaced by the Cluster Adapter M28





Cluster Adapter M10A1

No picture available

Overall length: 56 inches
Diameter: 15.3 inches


General: The cluster adapter is streamlined in shape, and, when filled, it becomes a 500-pound aimable cluster designed to be carried by any plane equipped to carry a 500-pound bomb.  Clusters formed with this adapter are the AN-M14, which contains 104 Incendiary Bombs AN-M50TA2, four AN-M50XA3 Type A, and Two AN-M50XA3 Type B; and the AN-M17A1, which contains 88 Incendiary Bombs AN-M50A2, 16 AN-M50XA3 Type A, and six AN-M50XA3 Type B.

The cluster adapter consists of a thin metal case with a channel bar extending through the center, and a standard tail fin fixed to the after end plate by means of a single heavy bolt.  At the forward end, a rounded nose fairing is fastened to the forward end plate.  From the fuze seat, a length of primacord extends through a thin metal tube to the after end of the adapter.  The adapter is equipped with three suspension lugs, the center lug added for use in British planes.  When the cluster adapter is loaded, the bombs are packed around the channel bar and the assembly is held in place by nine metal straps.


Operation
: On release, the arming wire is pulled, allowing the fuze to arm and fire at the pre-set time.  When the fuze fires, the primacord is detonated, breaking the metal straps holding the assembly together and allowing the bombs to fall free.


Remarks: The Cluster Adapter M10A1 is similar in appearance to the E6R2, but differs internally.  The bombs in the M10A1 are packed around a channel bar, while in the E6R2 the cluster bars surrounding the bombs hold them in place.







Cluster Adapter M23


Overall length: 59.5 inches
Body diameter: 14.75 inches
Tail width: 19 inches


General: Cluster Adapters M23 are used in forming 500-pound aimable clusters of incendiary or chemical bombs.  Cluster may be carried by planes equipped to handle 500-pound bombs.  They are designed for use in high- and medium-altitude bombing, the flight characteristics resembling those of the Practice Bomb M38A2


Description: The cylindrical halves of the cluster wall are joined at the top by a suspension bar and at the bottom by a burster-shield support bar.  Cluster bars, fitted into the end plates, hold the bombs in position inside the adapter.  Ballast weights are bolted by studs to the front and rear of the adapter's end plates.  Nine steel straps, drawn tight and fastened by a metal connector, are attached to release buckles which are placed on alternate sides of the suspension bar.  The buckles are held closed by two release wires attached to a release lever, which in turn is attached to a stud on the tail cone.  The tail assembly is composed of a modified box-type fin on a conical support, with two tail-fuze adapters attached to opposite sides of the cone.  The long stud, which extends through the rear ballast weight, supports the tail assembly.

The primacord wiring of the adapter is in two sections.  A metal tube channels a 60-inch length of primacord from the forward end of the burster shield, through the tail cone, and into the base of the "long" fuze adapter.  A 31-inch length extends from the tail cup into the "short" fuze adapter.


Clusters: Bombs are clustered in two sections, 19 bombs in each, with the nose to the front of the cluster.




Operation: On release, the arming wires are withdrawn and the two fuzes arm.  Upon expiration of the time setting, the "short" fuze operates to set off the booster and the primacord, which is channeled to the fin-retaining cup.  The cone is blown off by the primacord detonation, thereby withdrawing the buckle release wires and opening the cluster.  Upon failure of the "short" fuze to function, the "long" fuze operates two seconds later.  This detonates the primacord extending the length of the cluster, which shears the steel straps and releases the bombs.


Remarks: Some lots of adapters were shipped without buckles and release wires, the release of the bombs being dependent on the severing of the steel strapping bands.  The primacord from the "short" fuze is taped at a right angle to the primacord leading from the "long" fuze, to form one primacord assembly.  Operation of either fuze would detonate the primacord extending the length of the cluster, thereby severing the steel strapping bands and releasing the bombs.





115-pound Chemical M70


Overall length: 48.7 inches
Body length: 40.4 inches
Body diameter: 8.1 inches
Wall thickness: 0.224 inches

Tail length: 12.9 inches
Tail width: 10.9 inches
Tail weight: 3.5 pounds

Filling: Mustard (H)
Weight of filling: 57.1 pounds
Total weight: 122.5 pounds
Charge/weight: 46.6%


Construction: The bomb is made from a seamless steel tubing, with an ogival nose threaded to receive the nose fuze.  A burster-well tube runs the entire length of the body, fitting into a positioning cup at the rear.  The tail assembly consists of four fins welded to a sleeve, which is secured by a locking nut threading into the tail closing block.  The fins are supported by box-type struts.


Suspension: The bomb is carried horizontal by dual lugs seven inches on either side of the center of gravity, or a single lug 180 degrees removed at the center of gravity.

A cluster of four M70's is formed by using the Cluster Adapter M22.


Remarks: On impact, the fuze functions instantaneously, setting off the burster charge, which explodes the bomb and scatters the main filling.

The M70 can also be filled with white phosphorus, or with IM or NP incendiary mixture.





10-pound Smoke M77


Overall length: 19.5 inches
Body length: 19.5 inches
Body diameter: 2.9 inches

Filling: HC
Weight of filling: 9.5 pounds
Total weight: 13 pounds
Charge/weight: 73%


Construction: The body is a sheet-steel case extending the entire length of the bomb.  The tail cup fits into the after end of the casing, having a dome housing the Fuze M4.  The bomb does not have a device for stabilization in flight; therefore, an all-ways fuze is employed.




Operation: As the bombs are released from the cluster from the cluster, the arming pin is forced out by its spring, permitting the safety pin to enter the cavity in the striker.  Impact forces the striker and sleeve together, piercing the primer, which in turn ignites the first fire mixture and subsequently the H.C. smoke mixture.  The heat generated by the burning of the first mixture and the H.C. smoke mixture melts the zinc-alloy fuze body.  The smoke is then emitted through the fuze hole in the tail cup.


Remarks: Once the arming pin jumps out, the fuze is armed, and any attempt to reinsert the pin may cause the fuze to function.






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

Monday, 27 August 2018

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

Tuesday, 21 August 2018

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