Monday, 15 October 2018

American Projectiles and Explosives - Chemical, Incendiary, Smoke - "AN" Series Bombs (Part 2)





American Projectiles and Explosives



Explosive Bombs



"AN" Series




100-pound Incendiary AN-M47 Series

No picture available

AN-M47A2
Overall length: 48.9 inches
Body length: 39 inches
Body diameter: 8.1 inches
Wall thickness: 0.06 inches
Tail length: 12.9 inches
Tail width: 10.9 inches

Filling: Mustard gas, White Phosphorus, or Gasoline gel


Construction: The bomb body is a sheet-steel tube with a longitudinal seam weld.  The nose end is hemispherical.  A base plate at the rear end is welded to the tube.  Several bursters may be used interchangeably.  The burster runs the length of the bomb.  The Burster AN-M12 is a tube containing a 50-50 mixture of black powder and magnesium.  The Burster AN-M13 is a tube containing TNT and tetryl pellets at each end, and is used in conjunction with the Igniter AN-M9 (WP or Na).  The Na igniter will permit use over water.  Four vanes are welded to a truncated cone with box-type interior struts to form the tail.


Suspension: Horizontal suspension is provided by two eyebolts formed by holes in each half of the two suspension bands, the halves then being crimped together to form a complete band.  The bands are secured to the bomb body by tightening the bolts on the underside of the body.  One of the bands can be loosened and slipped to the center of gravity if single suspension is desired.

Two clusters are now standardized to provide single suspension for four to six bombs.  The Cluster Adapter M24 holds six AN-M47's; and the M22 has a capacity of four AN-M47's.




M47A2 - Gas: Loaded with 68.5 pounds of mustard gas.  Complete round weighs 98 pounds.  Inside of body is coated with oil.  Equipped with Burster M4.


M47A1 - Gas: Differs from the M47A2 only in that the interior is coated with black acid-proof paint instead of oil.


M47A - Chemical: Original design, has wall thickness of only 1/32 inch.  Not used for H filling.


M47A2 - Smoke: Main filling is 100 pounds of white phosphorus, and total weight is 127 pounds.  Burster M4 is authorized for high-altitude bombing; Burster M18 is authorized for low-altitude bombing. Burster M7 may be substituted for either.


M47A1 - Smoke: Like M47A2 - Smoke, with charge of 103 pounds of WP and total weight of 129.5 pounds, and interior coated with black acid-proof paint.


M47A2 - Incendiary: Loaded with 40-pound charge of gelled gasoline, either IM or NP, with total weight of 63.6 pounds.  Burster AN-M13 and Igniter AN-M9 (WP or Na) authorized for this bomb.


M47A1 - Incendiary: Like AN-M47A2, with interior coating of acid-proof paint instead of oil.


M47A3 - Incendiary: Identical to AN-M47A2, except that tail assembly is three inches longer.


M47A4 - Incendiary: On this modification, the suspension lugs are strengthened.














The Navy is procuring, at the present time [1947 - Date of Manual], Incendiary Bombs M47A2 loaded with PWP.  PWP consists of 75% WP and 25% plasticizer; it is more effective than WP, since it gives longer burning, reduces pillaring effect, and increases the anti-personnel effect.  The increased smoke efficiency is due to the larger particles of controlled size which result from the use of PWP.  The bomb contains 75 pounds of PWP and requires a Burster M20, which contains 3/4-inch-diameter tetryl pellets.






500-pound Incendiary AN-M76


Overall length: 59.2 inches
Body length: 45.3 inches
Body diameter: 14 inches
Wall thickness: 0.3 inches
Tail length: 13.9 inches
Tail width: 14.8 inches

Filling: Oil Gel PT 1

Weight of filling: 180 pounds
Total weight: 475 pounds
Charge/weight ratio: 38%


Construction: The body is of one-piece cast-steel construction, with a base plate welded to the body.  A burster tube 3.5 inches in diameter, 35.75 inches long, running through the center of the bomb, is welded to the nose and to the base plate.  The Adapter Booster M115 screws into the base plate.  The bomb tail is a cast-steel sleeve with four sheet-steel fins and internal box-type struts.  Suspension is accomplished by two suspension lugs welded on the body seven inches on each side of the center of gravity and by a single lug, 180 degrees removed at the center of gravity.


Operation: On impact, the fuzes function and detonate the 1.25-pound tetrytol burster in the burster tube and initiate the nine-pound white phosphorus igniter, which, in turn, ignites the main filling.

The bomb has a dispersal area of about 300 by 600 feet.


Remarks: White phosphorus is present in the igniter, and proper precautions should be taken in disposing of these bombs.  The incendiary mixture, PT 1, consisting essentially of paste of magnesium, gasoline, and a thickener, liberates heat at about four times that given off by the usual incendiary mixture IM.









500-pound Chemical AN-M78


Overall length: 59.25 inches
Body length: 46.7 inches
Body diameter: 14 inches
Wall thickness: 0.3 inches
Tail length: 13.9 inches
Tail width: 18.9 inches
Tail weight: 12.3 pounds


Filling: Hydrocyanic Acid (AC)
Weight of filling: 100 pounds
Total weight: 383 pounds
Charge/weight ratio: 26.1%

or

Filling: Phosgene (CG)
Weight of filling: 205 pounds
Total weight: 488 pounds
Charge/weight ratio: 42%

or

Filling: Cyanogen Chloride (CK)
Weight of filling: 165 pounds
Total weight: 448 pounds
Charge/weight ratio: 36.8%



Construction: In construction, the Chemical Bomb AN-M78 resembles the 500-pound G.P. Bomb AN-M64.  The body is of one-piece cast-steel construction with a Burster M15 well running the entire length of the bomb.  The burster is threaded internally at the nose to receive the nose fuze and at the rear to receive the Adapter Booster M115.  The base plug consists of a special forging welded to the case, containing the Needle Valve M1.  The tail is a standard box-type fin assembly secured to the bomb by a locking nut which threads onto the base plug.  Suspension is by two lugs seven inches on either side of the center of gravity, or by a single suspension lug 180 degrees removed at the center of gravity.


Remarks: The Adapter Booster M117 is used in conjunction with the Nose Fuze M127.  This nose fuze is required for aerial bursts with persistent gas agents.













1,000-pound Chemical AN-M79


Overall length: 69.5 inches
Body length: 53.6 inches
Body diameter: 18.6 inches
Wall thickness: 0.38 inches
Tail length: 18.5 inches
Tail width: 25.4 inches
Tail weight: 21.5 pounds


Filling: Hydrocyanic Acid (AC)
Weight of filling: 185 pounds
Total weight: 707 pounds
Charge/weight ratio: 26%

or

Filling: Phosgene (CG)
Weight of filling: 404 pounds
Total weight: 926 pounds
Charge/weight ratio: 44%



Construction: This chemical bomb resembles the 1,000-pound G.P. Bomb AN-M65, taking the same tail assembly, arming vanes, and fuzes.  The body is of one-piece cast-steel construction and has a steel burster well 2.5 inches in diameter which is placed axially through it and expanded in both the nose and the base plate before welding, thus eliminating any possibility of decomposition of chemical fillers due to the presence of crevices.  The base plate differs from that of the standard G.P. bomb in that it is a special forging welded to the case and containing the Needle Valve M1.  It also has a 1.25-inch filling hole closed by a soft iron gasket, a hard steel gasket plug, and a threaded closing plug.   The Booster M16 is used in the burster well and consists of a waterproof fiber tube filled with 4.45 pounds of tetrytol.  The standard 1,000-pound G.P. tail assembly consists of four fins welded to a sleeve which is held onto the base plate by a locking nut.  Horizontal suspension is accomplished by dual lugs 7 inches on either side of the center of gravity, or by a single lug 180 degrees removed at the center of gravity.


Operation: On impact with the ground, the tetrytol booster breaks the bomb case into a few large pieces without causing the chemical agent to "flash".  The initial cloud formed by the burst of this bomb, when filled with CG, covers an area of 100 yards in diameter within approximately eight to ten seconds.


Remarks: Attempts to disassemble the bomb or any of its components are to be avoided except for the fuzes, which may be removed provided it is necessary to return the bomb to storage.  Release of the filler is dangerous, and should not be undertaken except under exceptional circumstances.  In handling any damaged chemical bombs or in conducting surveillance tests by means of the Needle Valve M1, personnel should be equipped with rubber gloves and a gas mask.  The Adapter Booster M115A1 can be used in place of the M115.








Jettisonable fuel tanks ("fire bombs")




General: The "fire bomb" consists of a jettisonable fuel tank filled with gasoline gel (gasoline-Napalm mixture).  These bombs have been effective against personnel, wooden piers, inflammable stores, etc., with each bomb covering an area approximately 100 feet by 300 feet.

Various types of jettisonable fuel tanks are available for conversion into fire bombs.  A 150-gallon universal or interchangeable tank has been produced.  Stabilizers have been designed to give the fire bomb a more stable flight when dropped form a higher altitude.  The stabilizers are attached to the present tanks by a harness consisting of four cables which run along the longitudinal axis of the tank and are attached to a ring fitted around the nose.  The universal tank has clips welded to the after end, obviating the necessity of the nose ring and cable harness.


Filler: The filler is a gasoline-Napalm mixture.  Napalm consists of a mixture of basic aluminum soaps of fatty acids and napthenic acid, which in itself is inert and is used only to congeal the gasoline to the proper consistency.  Either 100 octane or 80 octane gasoline can be used, with 6% Napalm by weight added for the mixture.  Another powder, Marinco, consisting of 50% magnesium carbonate and 50% calcium carbonate, is added (7% of Napalm by weight) to prevent clogging in the outlet hose.

The Navy has developed the Incendiary Mixers Mk 1 Mod 0 and Mk 1 Mod 1, which mix the gasoline and Napalm in the correct proportions.





Next Time: Practice Bombs - Navy 

Monday, 1 October 2018

American Projectiles and Explosives - Chemical, Incendiary, Smoke - "AN" Series Bombs (Part 1)





American Projectiles and Explosives



Explosive Bombs



"AN" Series




2-pound Incendiary (Obsolete) AN-M52, AN-52A1, and AN-M52XA1


Overall length: 14.22 inches
Body length: 9.13 inches
Body diameter: 1.68 inches
Wall thickness: 0.35 inches
Tail length: 5.79 inches
Tail width: 1.68 inches

Filling: Thermate

Weight of filling: 0.4 pounds
Total weight: 2 pounds
Charge/weight ratio: 20%


Construction: The hexagonal cast-magnesium alloy body weighs 1.13 pounds.  The bore is one inch shorter than the body length, thus making a solid nose.  There are three vent holes below the primer cap assembly, to assist in initial burning.  The hexagonal sheet-metal tail is secured to the body with three screws.




Filling: Thermate is a composition of 80% Thermite and 20% first fire charge, see below.




Action: The spring-loaded safety plunger is depressed by the adjacent bomb; upon release from the cluster, it jumps out, leaving a thin brass cross holding the striker.  On impact, the striker breaks free from the cross, igniting the primer, first fire charge, and the thermate.  The thermate burns, igniting the magnesium alloy case.  The total burning time is eight minutes.


Remarks: In the Incendiary Bomb AN-M52A1, a primer of heavier metal is used, and the composition of the first fire charge is altered.  The AN-M52XA1 incorporates an explosive charge; otherwise it duplicates the AN-M52A1.






4-pound Incendiary AN-M50 Series



AN-M50A1
Overall length: 21.3 inches
Body length: 13.4 inches
Body diameter: 1.69 inches
Tail length: 8.7 inches
Tail width: 1.69 inches

Filling: Thermate

Weight of filling: 0.63 pounds
Total weight: 3.6 pounds
Charge/weight ratio: 17%


Construction: The hexagonal body of magnesium alloy, weighing 1.25 pounds, has an iron nose plug.  There are three vent holes below the primer cap assembly, to assist in initial burning.  The hexagonal sheet-metal tail is secured to the body with three screws.


Operation: The spring-loaded safety plunger is depressed by the adjacent bomb; upon release from the cluster, it jumps out, leaving a thin brass cross holding the striker, which breaks free on impact and ignites the primer.  The thermate burns, igniting the magnesium alloy case.  The total burning time is 9.5 to 10.5 minutes.




Remarks: AN-M50XA1. (Army: limited standard; Navy: obsolescent) contains 170 grains of black powder in a steel capsule at the nose, replacing a portion of the thermate.  The bomb burns approximately 1.5 minutes, until the black powder explodes, scattering burning magnesium over a wide radius.

AN-M50A2, similar to AN-M50A1, is waterproofed around the primer cap and first fire charge.

AN-M50XA2, similar to AN-M50XA1, has an explosive head consisting of a steel nose cap which houses three tetryl pellets, a detonator, and a delay fuse.  The delay fuse is ignited and sets off the detonator, exploding the tetryl pellets and projecting fragments of steel and burning magnesium.

AN-M50XA3 is identical to AN-M50XA2, except that the assembly around the primer cap and first fire charge is waterproofed.


Type A and Type B

AN-M50XA2 and AN-M50XA3 each have a Type A and a Type B.  Type A indicates that the delay from impact to explosion is two to four minutes; Type B indicates that the delay from impact to explosion is sixty to seventy seconds.

AN-M50TA2 is identical to AN-M50A2, except that it contains a secret toxic agent, which does not affect the burning properties of the incendiary.  Clusters carrying these bombs will have a green and a purple band painted around them.

AN-M50TXA3 combines the toxic feature of the AN-M50TA2 with the H.E. feature of the AN-M50XA3.  It is identical to the AN-M50TA2 as to appearance, except for a new longer, double-mortised steel nose, hollowed out to contain the explosive charge.  Because of the extra length of the nose, the column of therm-64C is 1 and 1/8 inches shorter.

The M50TXA3 is produced according to only one design or type, which gives a delay on the explosion of the H.E. charge of from 1 and 1/2 to 6 minutes.  A heat-sensitive detonator 2.556 inches long, which ignites at 300 degrees Celsius is housed in a hole drilled centrally through the upper part of the steel nose.  A 1/16-inch steel disk is placed in the bottom of the filling cavity of the bomb body, thus covering the top of the hole in the nose and insulating the detonator from the heat of the burning bomb.  The H.E. charge consists of tetryl pellets.






4-pound Incendiary AN-M54 Series (Obsolete)


AN-M54
Overall length: 21.35 inches
Body length: 13.6 inches
Body diameter: 1.69 inches
Tail length: 10 inches
Tail width: 1.69 inches

Filling: Thermate

Weight of filling: 1.6 pounds
Total weight: 4 pounds
Charge/weight ratio: 40%


Construction: The bomb body is a steel cylinder having a hexagonal nose plug.  The fuze is installed in the tail plug assembly.  There are three vent holes below the primer cap assembly, to assist in initial burning.  There is a hexagonal hollow sheet-steel tail.




Operation: The spring-loaded safety plunger is depressed by the adjacent bomb; upon release from the cluster, it jumps out, leaving the firing pin riding on a creep spring.  On impact, the firing pin overcomes its creep spring and strikes the primer, igniting the thermate, which melts the steel body and releases molten iron.


Remarks: AN-M54X is the same as AN-M54, except that next to the hexagonal nose plug a small portion of the thermate charge is replaced by a steel capsule containing 170 grains of black powder, which explodes and scatter the molten iron after the bomb has burned for about one minute.  It is limited standard for the Army, obsolete for the Navy.

AN-M54XA1 is the same as the AN-M54, except that inside the hexagonal nose plug there is a steel cylinder containing a tetryl high-explosive charge with a delay fuse and a detonator.  A thin spacer of magnesium is between the thermate and the fuse opening of the explosive cylinder.  After one minute of burning, the fuse is ignited, exploding the tetryl.  These bombs are no longer being procured for naval service, and should not be used except when Incendiary Bombs AN-M50A2 or AN-M69 are not available.  It is limited standard for the Army, obsolete for the Navy.











6-pound Incendiary AN-M69 and AN-M69X


Overall length: 19.5 inches
Body length: 19.5 inches
Body diameter: 2.87 inches
Wall thickness: 0.042 inches
Tail length (streamer): 54 inches

Filling: Gelled gasoline (NP or IM)

Weight of filling: 2.8 pounds
Total weight: 6 pounds
Charge/weight ratio: 46%


Construction: The bomb body is a hexagonal case with a nose cup welded to the forward end.  The nose cup, fuze and powder charges are sealed off from the rest of the case by an impact diaphragm and plug held in a cup-shaped sealing diaphragm.  The incendiary oil filling is held in a cheesecloth sock situated between the forward sealing diaphragm and the tail cup.

The tail assembly consists of a tail cup, tail retainer, and disc.  The tail cup is secured to the hexagonal case by beading, crimping, and heating.  Four gauze streamers, each 54 inches long, are attached to the tail retainer by the tail disc to stabilize the bomb and reduce the terminal velocity.




Operation: The spring-loaded safety plunger jumps out of the Fuze M1 upon release from the cluster, arming the fuze.  On impact, the striker overcomes its spring and detonates the primer cap, which ignites a lead-coated spitter fuse.  The spitter fuse burns from three to five seconds, allowing penetration, and ignites the black-powder booster charge.  This ignites the igniter-ejector charge consisting of two bags of black powder and oiled magnesium powder.  The combustion blows off the tail cup, ignites the incendiary filling and ejects it for a maximum of 75 yards.


Remarks: The bomb and the delay are calculated to permit penetration inside a structure before detonation.  The incendiary oil filling is of a very sticky composition and will normally adhere to any object, including vertical walls.

The AN-M69X incorporates a 4.5-ounce charge of tetryl to produce an anti-personnel effect.  Overall dimensions of the AN-M69X duplicate those of the AN-M69, but the amount of incendiary mixture is reduced (0.4 pounds less).  Operation of the Fuze M1 ignites a safety fuze lead terminating in the Detonator M106, which explodes the tetryl, fragmenting 65% of the bomb case after ejection of the incendiary material, following a pre-determined time delay of 0.5 to 6 minutes (30% - 1/2 minute; 30% - 2 minutes; 40% - 6 minutes).  The time delay is varied by adjusting the length of the safety fuse.





Next Time: Chemical, Incendiary, Smoke - "AN" Series Bombs (Part 2)

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