American Projectiles and Explosives - Army Practice Bombs

American Projectiles and Explosives



Practice Bombs

Army Practice Bombs

3-pound AN-Mk 5 Mod 1


See Navy Practice Bombs








20-pound M48

This is a dummy of the 20-pound Fragmentation Bomb AN-M41.  It has a two-ounce black-powder charge and uses the Fuze M110 or AN-M110A1 in the nose.  It is 21.8-inches long; weighs 19.7 pounds.  It is issued in practice bomb clusters M2 and M2A1.





23-pound M71 and M71A1


These are parachute-type practice fragmentation bombs for clustering.  They do not have a fuze or spotting charge, because of the presence of the parachute.  The parachute assembly is the M3, modified from the M4 by removal of the suspension assembly, hand assembly, and pull wire container.  M71 is 26.9 inches long; weighs 21 pounds.  M71A1 differs by the addition of the shoulder to the bomb nose.







100-pound M38A2



Overall length: 47.5 inches
Diameter: 8.13 inches
Weight (empty): 15.7 pounds
Weight (sand-loaded and spotting charge): 100 pounds


This bomb simulates a G.P. bomb of the same size.  The spotting charge is assembled in a sleeve at the base of the bomb, within the fin box.  Authorized spotting charges are M1A1, M3, and M4.






100-pound M75

Length: 47 inches
Diameter: 8 inches
Filler (hematite): 72 pounds
Total Weight: 101.3 pounds


This bomb is designed to provide a target reference for practice bombing over snow-covered ranges.  Resembling the chemical bomb of the same size, it consists of a light, sheet-metal case; a charge of red iron ore (hematite); a Burster M4; and a Fuze M108 in the nose.





100-pound M85


This model is a reinforced concrete design ordered to relieve a temporary shortage of the Practice Bomb M38A2 during the war.






Spotting Charge (Army)

M1A1

Overall length: 11.18 inches

Diameter: 3.43 inches

Weight: 4.25 pounds

Black-powder charge: 3 pounds

Bomb used in: M38A2

This type of spotting charge fits in the after end of the 100-pound Practice Bomb M38A2.  It produces a flash of flame and white smoke for observation of bombing accuracy.  When assembled in the bomb, the can of the charge protrudes two to three inches out of the bomb body.

The fuze is an integral part of the spotting charge assembly.  When the arming wire is pulled, the spring-loaded arming pin jumps out, leaving the inertia weight supported only by the combination firing pin and creep spring.  On impact, the inertia weight drives this firing pin into the shotgun-type primer, which, in turn, ignites the black powder.

M3: The Spotting charge M3 has a 2 and 1/3-pound dark smoke filling and a black-powder igniter.  It is 5/8 inches longer than the Spotting Charge M1A1, but otherwise is like it.  The M3, with its dark smoke filler, is well adapted for bombing practice over snow-covered terrain.  The black-powder igniter charge contains approximately 425 grains.  It is used in the Practice Bomb M38A2.


M5

Overall length: 7.37 inches
Diameter: 2.95 inches
Material: Glass
FS filler: 14.4 fluid ounces

The Spotting Charge M5 consists of a glass bottle filled with FS smoke mixture.  An ordinary bottle cap seals the mixture.  The bottle is held to the Practice Bomb M38A2 by a wire twisted around the neck of the bottle and attached to the tail vanes.  The charge assembly weighs 2.54 pounds.

Next Time: Guided Missiles - Introduction & Bureau of Ordnance Missiles

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


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 required.

Two clusters are now standardized to provide a 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 use 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 WP and total weight of 129.5 pounds, and interior coated with black acid-proof paint.


AN-M47A2 - Incendiary: Loaded with 40-pound charge of gelled gasoline, either IM or NP, with total weight of 68.6 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.


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


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










The Navy is procuring, at the present time [Manual Date 1949], 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 

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

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 - Navy "MK" Series (Part 1)

American Projectiles and Explosives



Explosive Bombs

Navy "MK" Series


General

The Navy-designed bombs are generally similar to Army bombs of the same class.  Since the formation of the Army-Navy Standard Board, early in 1941, the Navy has concentrated on designing bombs for naval targets and for carrier handling, leaving the other types of bombs to Army designers.


Color

The Navy formerly used a yellow paint over all; later, grey over all, with a yellow disc painted between the lugs if the bomb is a high-explosive type.  Later productions may be found painted olive drab overall, with yellow bands.

100-pound G.P. Mk 1 Mods 2 and 3, Mk 4 Mods 1-4 (Obsolescent)

Mk 1

Overall length: 48.8 inches
Body length: N/A
Body diameter: 7.9 inches
Wall thickness: N/A
Tail length: 21 inches
Tail width: 9.8 inches
Filling: TNT
Weight of filling: 65 pounds
Total weight: 116 pounds
Charge/weight ratio: 56%

Mk 4

Overall length: 36.2 inches
Body length: 28 inches
Body diameter: 8 inches
Wall thickness: 0.175 inches
Tail length: 9.1 inches
Tail width: 11 inches
Filling: TNT
Weight of filling: 55 pounds
Total weight: 120 pounds (Mod 1) - 195 pounds (Mod 4)
Charge/weight ratio: 45.8% (Mod 1) - 52.8% (Mod 4)

Body construction: Mk 1 has two sheet steel castings welded together, the bomb having a "tear drop" shape.  Mk 4 is a single-piece steel forging; cylindrical, with ogival nose.


Suspension: Mk 1 is horizontally suspended by two lugs welded on the body; it may have single lug or trunnions on the band.  Mk 4 has two lugs welded on the body 14 inches apart; with a single lug welded on the opposite side.


Color and markings: Grey overall with a four-inch yellow disc between the two lugs, indicating H.E.  The color may be yellow overall.


Tail construction: Mk 1 has four vanes which pass down over the body and are welded to a tail cone.  The vanes are fastened to the body of the bomb by screws and are braced by two sets of bar struts riveted to the vanes.  Mk 4 has four vanes welded to a sleeve which is secured to the bomb body with a locking nut.  Box-type internal struts are welded to the vanes.

500-pound G.P. Mk 3 Mod 1, Mk 9, and Mk 12 Mods 0-2 (Obsolescent)

Mk 12 Mod 2

Overall length: 59.5 inches
Body length: 42.6 inches
Body diameter: 14 inches
Wall thickness: 0.36 inches
Tail length: 20 inches
Tail width: 19.4 inches
Filling: TNT
Weight of filling: 256 pounds
Total weight: 504 pounds
Charge/weight ratio: 50%

Body construction: One-piece steel, forged or drawn; cylindrical, with ogival nose.


Suspension: Horizontal suspension by two lugs or trunnions on band for dive bombing.


Color and markings: Grey overall with yellow disc between lugs, indicating H.E.


Tail construction: Four sheet metal vanes are welded to a cone which is attached to the body by a nut which surrounds the fuze.  Box-type struts are used.


Remarks: The 500-pound G.P. Bomb Mk 12 Mod 2 is still to be found in the field, but is no longer being manufactured.  The other Marks are obsolete.  The Mk 12 and Mk 12 Mod 1 differ from the Mk 12 Mod 2 as follows: Trunnions are welded to the body.  They also have two hoisting lugs welded to the body, a female base plate, and a right-angle fin sleeve instead of the conical type.

1,000-pound G.P. Mk 3, Mk 5, Mk 9, and Mk 13 Mods 0-2 (Obsolescent)

Mk 13 Mod 2

Overall length: 72.6 inches
Body length: 53 inches
Body diameter: 17.7 inches
Wall thickness: 0.45 inches
Tail length: 22.3 inches
Tail width: 23.5 inches
Filling: TNT
Weight of filling: 511 pounds
Total weight: 1,005 pounds
Charge/weight ratio: 51%

Body construction: One-piece drawn or forged steel; cylindrical with ogival nose.


Suspension: The bomb is suspended horizontally by two suspension lugs, or by trunnions on the band around the body for dive bombing.  A torpedo sling guide key is welded to the bomb for suspension in torpedo slings.


Color and markings: The bomb is painted grey overall, with an 11-inch yellow disc between the suspension lugs to indicate H.E.


Tail construction: Four vanes welded to the tail cone, which is secured to the body by a locking nut which screws onto the threaded collar of the base plate.


Remarks: Though this bomb may be found in the field, it is no longer being manufactured.

The Bombs Mk 3, Mk 5, and Mk 9 are declared obsolete and will be expended in practice.

The Mk 13 and Mk 13 Mod 1, also declared obsolete, differ from the Mk 13 Mod 2 as follows: Trunnions are welded to body.  There are two hoisting lugs welded to the body, in addition to a single hoisting lug between the suspension lugs.  They have a female base plate instead of the conical type.

1,000-pound G.P. Mk 36

Overall length: 71.2 inches
Body diameter: 18.7 inches
Filling: TNT
Weight of filling: 558 pounds
Total weight: 1,012 pounds
Charge/weight ratio: 55%

General: The 1,000-pound Bomb Mk 36, is a modified version of the 1,000 pound G.P. Bomb, AN-M44.  These modifications provide for the use of Nose Fuzes AN-Mk 219 or Mk 221, the use of Tail Fuzes Mk 223 or Hydrostatic Mk 229 Mod 3, a Navy-type hoisting lug and guide key, trunnions for dive bombing, and an explosive filling of TNT, rather than 50-50 Amatol.


Description: This bomb has two suspension lugs, spaced 14 inches apart, welded to the bomb body for suspension from double-hook racks and shackles.  A guide key is provided on the opposite side of the bomb for sling suspension.


Remarks: The G.P. Bomb Mk 36 was designed primarily by the Navy as an alternate for the 1,000-pound G.P. Bomb Mk 13 Mod 2.

7-inch 100-pound Depth Bomb Mk 52

Overall length: 45.9 inches

Body length: 7 inches
(Note: I believe this should be Diameter, not Length)

TNT
Weight of filling: 45.3 pounds
Total weight: 99.1 pounds
Charge/Weight ratio: 46%

Torpex
Weight of filling: 50.3 pounds
Total weight: 104.1 pounds
Charge/Weight ratio: 49%

General: This is a light-case, fast sinking, round-nose bomb for use by airships.  It is carried in a Bomb Rack Mk 53 and, accordingly, has no trunnions, trunnion bands, or suspension lugs.  A cylindrical shroud is fastened to the tail section by four vanes.  The entire tail assembly is fastened to the rear of the bomb body by six flat-head machine screws.  A cast-iron nose, into which is fitted a booster can, is secured to the bomb body.  The bomb is filled with either TNT or Torpex.  The Nose Fuze Mk 140 will normally function on impact with a solid object below the surface of the water, but will also function upon striking the surface of the water at any velocity greater than approximately 300 feet per second.  This velocity may be attained in a free fall from a vertical height of 1,400 feet.

650-pound Depth Mk 29 (Obsolete) and Mk 37 (Obsolete)

Mk 29

Overall length: 70 inches
Body length: 41 inches
Body diameter: 17.7 inches
Wall thickness: 0.12 inches
Tail length: 36 inches
Tail width: 17.7 inches
Filling: TNT
Weight of filling: 464 pounds
Total weight: 657 pounds
Charge/weight ratio: 70%

Mk 37

Overall length:63 inches
Body length: 41 inches
Body diameter: 17.7 inches
Wall thickness: 0.12 inches
Tail length: 29 inches
Tail width: 17.7 inches
Filling: TNT
Weight of filling: 464 pounds
Total weight: 659 pounds
Charge/weight ratio: 70%



Body construction: These bombs are manufactured with a hemispherical nose reinforced with a steel disc.  The suspension lugs are reinforced with a steel strip.  A flat-nose attachment, in the shape of a bucket and fitting down under the nose of the bomb, can be used to improved underwater trajectory.  The vacant spaces are then filled with plaster of paris.  These attachments increase the weight by 72 pounds.


Suspension: Horizontal suspension is provided by the usual two suspension lugs, with threaded holes on each side 90 degrees removed to receive trunnion lugs for the displacement gear of dive bombers.


Color and markings: The bombs are painted olive drab or grey overall, with an 11-inch yellow disc between the two suspension lugs.  They may be light grey overall.


Tail construction: Four sheet-steel vanes are welded to the tail cone, which is secured to the body by a locking nut screwing onto the rear of the body.  An annular strut is used around the rear of the vanes.  The tail of the Mk 37 was shortened by seven inches so that the Tail Fuze Mk 229 could arm more readily.  Otherwise, the tail is similar to that of the Mk 29.


Remarks: AN-Mk 219 will not arm under 2,500 feet of altitude if the flat-nose attachment is used.

AN-M103 or AN-M103A1 will not arm with the flat-nose attachment, unless special arming vanes are used.

An extender is supplied with each bomb to permit installation of the Hydrostatic Fuze AN-Mk 224 or AN-Mk 234 in the longer athwartships tube.

The Mk 29 is converted to the Mk 37 by replacing the tail.

Because of numerous instances in water crash landings where depth bombs fuzed with the Athwartships Fuze AN-Mk224 or AN-Mk 234 exploded, these two fuzes have been suspended from use.  As a consequence, the Depth Bombs Mk 29 and Mk 37 may be used only if a nose impact fuze is installed.

Next Time: Navy "MK" Series (Part 2)