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