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
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 inchesBody 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 inchesBody 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 inchesBody 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)
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/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
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)
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.