American Guided Missiles - A.A.F. Missiles (Part 1)

American Projectiles and Explosives



Missiles

A.A.F. Missiles

1,000-pound VB-1 "Azon" Air-to-Surface Missile

Body diameter: 18.8 inches
Warhead: 1,000-pound G.P. Bomb AN-M44, M65, or M65A1


Construction: The VB-1 is a guided bomb employing a 1,000-pound G.P. body to which a special tail unit has been attached, replacing the standard tail assembly.  The VB stands for "Vertical Bomb" and indicates that the bomb is normally released from high altitude by use of a conventional bombsight and that the guided action for the bomb is relatively small, so that direction of the trajectory at the time of impact is essentially vertical.


Tail unit: More popularly known as the "Azon" bomb, since it can be controlled only in azimuth 2,000 to 3,000 feet to either side of the normal point of impact, the VB-1 has its controls in a radio receiver housed in the tail unit.  A radio transmitter, operated by the bombardier in the parent aircraft, sends signals to the receiver, which, in turn, activates a servo motor controlling the movement of the rudders in the tail fins.  Also incorporated in the tail is a gyro and solenoid system which prevents the bomb from spinning by changing the pitch of the small ailerons in the fins.

Guide flares attached to the after end of the tail unit assist the bombardier in following the flight of the VB-1.  Three flares, the T6E1 (white), T7E1 (red), and T8E1 (green) with an intensity of 1,000,000 candlepower each, are electrically armed and ignited three to four seconds after release, and burn from one to two minutes.  Three mechanically armed and ignited flares, T21, T22, and T23 are under development.


Suspension: Suspension lugs are welded to the case in a manner similar to the G.P. bombs.







1,000-pound VB-3 "Razon" Air-to-Surface Missile

Body diameter: 18.8 inches
Warhead: 1,000-pound G.P. Bomb AN-M44, M65, or M65A1


Construction: The VB-3 is a guided bomb similar to the VB-1, with the major difference that its flight may be controlled in range as well as in azimuth, and is known generally as the "Razon" bomb.  Like the VB-1, it has a special tail unit fitted to a 1,000-pound G.P. body, and is normally released from high altitude by use of a conventional bombsight, the guided action being relatively small, so that the trajectory at the time of impact is essentially vertical.


Tail unit: The controls for the VB-3 are contained in the cylindrical section of the tail unit and consist of a radio receiver, a gyro, and a servo motor.  Surrounding this unit are two shrouds; the forward shroud merely stabilizes the bomb in flight, while the after contains the stabilizing ailerons and range/azimuth control ailerons.

On each of the four struts supporting the after shroud is an aileron controlled by the gyro.  These four ailerons steady the bomb and prevent it from rotating while in flight.  They are set 90 degrees apart and operate in pairs; ie, those ailerons placed opposite to each other move together in unison.

Four move ailerons are located on the outer surface of the after shroud.  These are ailerons which control the trajectory of the bomb and adjust its flight in azimuth and range.  They also work in pairs, and are operated by connecting rods which pass through the control unit and are activated by the servo motor.  At present, two bombardiers are required with the VB-3 bomb; one controls range and the other azimuth.  They work independently of each other and, by use of a special bombsight, they are always able to see the bomb in flight, superimposed on the target.  As the bombardiers manipulate their control switches, radio waves are sent to the receiving unit in the tail.  This unit activates the servo motor, which, in turn, moves the ailerons on the shroud, altering the flight of the bomb.

As in the VB-1, flares are employed to assist the bombardier in the visual control of the flight of the bomb.  Currently used flares are the T6E1 (white), T7E1 (red), and T8E1 (green).  They are of 1,000,000 candlepower each, electrically ignited three to four seconds after release, and with one to two minutes of burning time.  Three mechanically activated flares, T21, T22, and T23 are under development.


Suspension: Suspension lugs are welded to the case in a manner similar to the G.P. bombs.









1,200-pound VB-6 "Felix" Air-to-Surface Missile

Overall length: 91.2 inches
Overall diameter: 18.6 inches
Total weight: 1,202 pounds
Warhead: 1,000-lb G.P. Bomb AN-M65


General: The VB-6 is a heat-homing, high-angle bomb for attack against targets which give higher heat radiation than the surrounding areas.  An added nose (84 pounds) and special tail assembly (143 pounds) carried on a standard 1,000-pound G.P. Bomb AN-M65 contain the heat-seeking equipment and the mechanism which operates the airfoil controls.  Requisites for proper performance are clear weather and a target which has necessary heat-radiation quality.  The bomb is sighted and released by standard Norden procedure.


Control: The tail assembly, which resembles that of VB-3, has range and azimuth control surfaces on an octagonal shroud, and gyro-stabilizes ailerons to keep the missile from spinning.  When a target passes into view, the increased heat radiations stimulate the nose unit to apply the necessary corrections to the shroud surfaces.


Suspension: Standard lugs.


Remarks: The Nose Fuze T85 has a special plate attached to it, on which the nose assembly is bolted.









12,000-pound  VB-13 "Tarzon" Air-to-Surface Missile

No picture available

Overall length: 21 feet
Warhead: 12,000-pound G.P. Bomb T10


General: This missile consists of a modified Bomb T10 with a circular, 54-inch shroud about its body for lift, an octagonal tail surface for control, and the radio control mechanisms for guidance in range and azimuth.  It is well suited for use against targets requiring direct hits, deep penetration, and heavy explosive loads.  Good visual bombing conditions are necessary, and, when several bombs are to be used on the same target, all must be dropped together, since the first explosion will visually obscure the target area.  Another tactical requirement is for the dropping aircraft to remain on its bomb run until the missile strikes.


Control: The control mechanism and procedure are fundamentally similar to those of the VB-3.


Suspension: Depending on the aircraft employed; generally similar to that of the Bomb T10.

Next Time: A.A.F Missiles (Part 2) and the "Loon"

American Guided Missiles - Introduction & Bureau of Ordnance Missiles

American Projectiles and Explosives



Missiles

Introduction

General

One of the newest trends [c.1947] in American ordnance development, guided missiles became service items in the last months of World War II.  Guidance was applied to modified bombs, winged glide bombs, and standard aircraft, and in jet- and rocket-propelled airframes.

Guided missiles have great range, high payload capacity, and extreme accuracy; and their progress in designed has proceeded so rapidly that on only a few items has the design become standardized or "frozen".  All the missiles included here were at least in the testing stage and were being pursued as active projects at the time of writing.  Furthermore, only those missiles designed for combat or military purposes - none of the basic research items - are included; and, of these, only their ordnance components can be described in detail.


Guidance

American missiles are usually guided by remote radio control, the receiver in the missile acting through servo units to position the air foils.



Intelligence

The person controlling the flight of the missile will guide its path on the basis of information obtained visually, through a television receiver, or by ordinary radar tracking.  Some missiles have automatic guidance features, of such a nature that, once the target has been "shown" to the missile's intelligence unit, it will automatically "home on" to its destination unassisted.



Propulsion

Depending on the particular item, a missile may be powered by gravity, aircraft, engines, JATO units, rocket motors, or jet motors.



Warheads

Thus far, guided missiles have adapted standard bombs as their explosive payloads.  Fuzing of these bombs differs from the standard fuzes in that the fuzes must be made in an elbow shape, in order to fit in the fuze pockets and, at the same time, permit vane arming.



Cognizance

For the Navy, the Bureau of Ordnance and the Bureau of Aeronautics are developing guided missiles; for the Army, the Air Forces are in charge of the program.






Bureau of Ordnance Missiles

1,200-pound "Dove" Bomb Mk 64 (Air-to-Surface Missile)

Overall length: 84.5 inches
Overall diameter: 18.75 inches

Weight of intelligence units and special tail: 183 pounds
Warhead (1,000-pound G.P. Bomb AN-M65): 975 pounds

Total weight: 1,160 pounds



General: The Bomb Mk 64 is an experimental heat-homing bomb, consisting of a detecting, computing, and guiding mechanism housed in a nose attachment fitted on the 1,000-pound G.P. Bomb AN-M65.  It is designed for attack on maneuvering targets and is effectively employed in both high-angle and dive-bombing runs against objects which have sufficient thermal contrast to their background.

"Dove" is designed to fit the normal plane stowage, but carrying capacity is sometimes reduced because of the missile's increased length.  The special Bomb Fin Mk 1 is a box-kite shape and eight inches longer than the standard tail for this bomb.


Control: Aerodynamic control is effected in range and azimuth by means of four movable nose deflectors independently controlled, which thus form quadrants of a cylindrical surface whose axis is parallel to that of the bomb.  The deflectors may be extended a maximum distance of 4 and 1/2 inches.  The movement of the deflectors is determined by the intelligence unit, which consists of the heat-detecting eye, gyro system, auxiliary electronic relays, servo motors, and battery.







1,600-pound "Bat" S.W.O.D. Mk 9 (Air-to-Surface Missile)

Overall length: 11.9 inches
Wing span: 10 feet
Total weight: 1,600 pounds
Warhead: 1,000-pound G.P. Bomb AN-M65


General: S.W.O.D. (Special Weapons Ordnance Device) Mk 9, or "Bat", is a glide bomb equipped with a radar homing set mounted in the nose.  It is designed primarily for attacking marine targets, and is effective for night or day attacks upon shipping in any weather in which the parent plane can fly.  The launching planes need not stay in the vicinity of the target, and may release as many as four of these missiles in salvo.

The airframe consists of plywood sections which are fitted around the Bomb AN-M65.  Control surfaces consists of an elevon on each wing which can be moved to control pitch or bank.  There are no control surfaces on the tail.

To ensure destruction of the intelligence system, the Demolition System Mk 122 is used.

Installation of the Fuzes Mk 235 and Mk 236, with their outside windmills and flexible arming stems, is standard.


Control: This missile has its own radar transmitter and receiver.  When the target is located on the scope of the monitor unit in the plane, it is put into the range step of the missile's scope and is automatically kept there.  At the correct instant, determined by a glide ratio scale, the missile is released and is guided to its target by the radar signal in its own scope.  The guiding radar supplies corrections to the servo system, which is also controlled by a gyro pilot, the device which maintains flight attitude.


Suspension: Standard bomb lugs are employed on the airframe.  Also, there is the multi-conductor cable connecting the missile's radar with the monitor set in the plane, known as the umbilical cord.


Demolition System: This destructor assembly consists of the S-122-11G switch, Junction Box Mk 1 Mod 0, primacord connectors, and ten Demolition Charges Mk 4.  The S-122-11G switch incorporates an inertia weight, held by a spring tension of 11G, which will topple if that force is exceeded in an impact.  When this inertia weight topples (it is mounted on a universal pivot) the contact bar, which has been transmitting the spring tension to the inertia weight, rotates because of the spring load and completes the electrical circuit across the contacts.  This switch has an arming stem, connected to windmill vanes mounted on the outside of the missile fuselage, which unscrews to arm the switch.  These vanes have an arming wire to prevent rotation before release from the parent aircraft.  On one side of the switch is a clear plastic inspection port.  Tension on the spring is pre-set at 11g when the switch is assembled at the factory.

When the switch completes the circuit, current from the battery sets off the electric blasting cap in the junction box, which fires the primacord connectors and then the TNT blocks, placed around the intelligence unit.


Remarks: The S.W.O.D. Mk 9 is commonly known as "the 1,000-pound Bat".  The S.W.O.D. Mk 10, built around a 2,000-pound bomb is not being actively developed, because it is felt that the 1,000-pound size is large enough for currently projected use.

Next Time: Bureau of Aeronautics 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 - Explosive Bombs - "AN" Series (Part 3)

American Projectiles and Explosives



Explosive Bombs

"AN" Series

A.P. AN-Mk 33 (1,000-pound) and AN-Mk 1 (1,600-pound)

AN-Mk 33

Overall length: 73 inches
Body length: 58 inches
Body diameter: 12 inches
Tail length: 17 inches
Tail width: 16 inches

Filling: Explosive D, Cast TNT
Weight of filling: 140 pounds
Total weight: 1,025 pounds
Charge/weight ratio: 14%

AN-Mk 1

Overall length: 83.5 inches
Body length: 69.5 inches
Body diameter: 14 inches
Wall thickness: 1.3 inches
Tail length: 20.5 inches
Tail width: 20.6 inches

Filling: Explosive D, Cast TNT
Weight of filling: 215 pounds
Total weight: 1,590 pounds
Charge/weight ratio: 14%



Construction: The bodies are of single-piece, forged, machined construction, with pointed noses, parallel sides, and alight boat tailing.  The base plate is of the male type.  Suspension in the 1,600-pound A.P. Bomb Mk 1 design was by means of lugs welded to bands, the bands being positioned by grooves on the external bomb surface.  The newer designs, AN-Mk 1 and Mk 33, are suspended by fittings which screw into holes drilled into the bomb case and secured by bolts.  The normal box-type tail assembly is used on these bombs.


Filling: The main filling of these bombs is pressed Explosive "D" or cast TNT.  The tail fuze pocket requires use of the granular TNT Auxiliary Booster Mk 1.


Remarks: The later 1,600-pound A.P. Bombs Mk 1 Type were grooved to position the suspension band.  Older bombs had a stud which fitted into a hole in the bomb body.







325-, 350-pound Depth Mk 17 (TNT - Obsolete), Mk 17 Mod 1 (TNT), AN-Mk 17 Mod 2 (TNT), AN-Mk 44 (Torpex), AN-Mk 41 (TNT), and AN-Mk 47 (Torpex)

AN-Mk 17 Mod 2; AN-Mk 44

Overall length: 52.5 inches
Body length: 31.1 inches
Body diameter: 15 inches
Wall thickness: 0.06 inches
Tail length: 20.2 inches
Tail width: 20.6 inches

AN-Mk 41; AN-Mk 47

Overall length: 49.9 inches
Body length: 27.8 inches
Body diameter: 15 inches
Wall thickness: 0.06 inches
Tail length: 24.6 inches
Tail width: 15.4 inches


AN-Mk 17 Mod 2
Filling: TNT
Weight of filling: 224 pounds
Total weight: 325 pounds
Charge/weight ratio: 68.9%


AN-Mk 44
Filling: Torpex
Weight of filling: 249 pounds
Total weight: 350 pounds
Charge/weight ratio: 71.1%


AN-Mk 41
Filling: TNT
Weight of filling: 227 pounds
Total weight: 347 pounds
Charge/weight ratio: 65.4%


AN-Mk 47
Filling: Torpex
Weight of filling: 252 pounds
Total weight: 355 pounds
Charge/weight ratio: 70.9%

Nose construction: Depth Bombs AN-Mk 17 Mod 2 and AN-Mk 44 have round noses, and can use the flat-nose attachment; AN-Mk 41 and AN-Mk 47 are flat-nosed.


Body construction:
-AN-Mk 17 Mod 2 and AN-Mk 44: These depth bombs are made with round noses welded to a cylindrical steel tube.  There is a strengthening disc around the nose and a steel strip along the suspension lugs to reinforce the body.  The transverse fuze pocket is 11.9 inches abaft the nose.  To prevent ricochet and improve underwater trajectory, a flat-nose attachment is made for these bombs, the attachment being in the shape of a bucket which fits down over the nose and is filled with plaster of paris, increasing the weight of the bomb by 44 pounds.  The bomb case is extremely thin.

-AN-Mk 41 and AN-Mk 47: These bombs are constructed with a flat nose, there being a slight taper from the walls to the nose.  The body is in three pieces.  The sides are tubular with a transverse fuze pocket tube welded in place 15 inches abaft the nose.


Suspension: Suspension of these bombs is by the usual dual or single lugs, the lugs being welded to the bomb.  The single lug is actually somewhat different than is usually found, being in the form of a bracket rather than a lug.  Trunnions on a band are for displacement gear in dive bombing.


Tail construction: Instead of employing the box-type tail, these bombs use a drum tail.  As seen from the after end, it is circular and has four fins extending at right angles to each other.  The fins are spot-welded to a cone which fits over the after end of the bomb.  The fins are also spot-welded to the drum shroud.  The tail is bolted onto the base of the bomb.


Markings: TNT-loaded bombs have weight and Mark number stencilled in yellow; Torpex-loaded bombs have these items stencilled in blue.


Remarks: The 325-pound Depth Bomb Mk 17 is TNT-loaded but has a light tail assembly; the Mk 17 Mod 1 is the same, except that a sturdier tail assembly is used.  The AN-Mk 17 Mod 2 is similar to the Mod 1, but has a larger filling hole.

The Mk 17 is obsolete; the Mk 17 Mod 1, AN-Mk 17 Mod 2, AN-Mk 44, AN-Mk 47, and AN-Mk 41 are obsolescent.








325-, 350-pound Depth AN-Mk 53 Mod 1 (TNT),  AN-Mk 54 Mod 1 (HBX), Mk 53 (TNT), and Mk 54 (Torpex)

Overall length: 52.5 inches
Body length: 33.25 inches
Body diameter: 13.8 inches
Wall thickness: 0.06 inches
Tail length: 24.5 inches
Tail width: 13.9 inches


AN-Mk 53 Mod 1; Mk 53
Filling: TNT
Weight of filling: 225 pounds
Total weight: 330 pounds
Charge/weight ratio: 68%


Mk 54
Filling: Torpex
Weight of filling: 250 pounds
Total weight: 354 pounds
Charge/weight ratio: 70.6%


AN-Mk 54 Mod 1
Filling: HBX
Weight of filling: 250 pounds
Total weight: 354 pounds
Charge/weight ratio: 70%



Body construction: The cylindrical welded sheet-steel body has a flat nose.  A base closing plate is secured to the rear of the bomb by four bolts.  A base closing plate is secured to the rear of the bomb by four bolts.


Suspension: These bombs are suspended horizontally by two lugs seven inches on each side of the center of gravity, or by a single lug at the center of gravity and 180 degrees removed from the other lugs.  There is no external band, the bombs being strengthened internally by a band which is fitted into the bomb at the center of gravity.  Trunnions for dive bombing may be threaded to the case and internal strengthening band.


Tail construction: Welded to the tail cone are four vanes which are strengthened by interior box-type struts, and an exterior wide ring strut.  The tail cone is secured to the base closing plate by four bolts.


Markings: Olive drab overall.  "Mk 53 - 325 lb. Depth Bomb", "Mk 54 - 350 lb Depth Bomb" stencilled on the respective bomb bodies in yellow if the filling is TNT, or in blue if the filling is Torpex.


Remarks: These two bombs (identical except for filling) have been designed to replace depth bombs using athwartship fuzes, since difficulties have been encountered at times in the past with the Athwartship Fuzes AN-Mk 224 and AN-Mk 234.  The Depth Bombs Mk 53 and Mk 54 will use the Tail Hydrostatic Fuze AN-Mk 230 and a nose fuze, having no athwartship pocket.

The Depth Bombs AN-Mk 53 Mod 1 and AN-Mk 54 Mod 1 differ from the Depth Bombs Mk 53 and Mk 54 respectively in that the suspension lugs are welded on, instead of being of the screw type.  In addition, the walls of the explosive cavity of the two bombs are coated with an asphaltic composition known as Hot Melt.  The AN-Mk 54 Mod 1 is loaded with HBX rather than Torpex.

Only the modifications of the Depth Bombs Mk 53 and Mk 54 have been standardized as AN bombs.











1,000-pound Aircraft Mine AN-Mk 26 Mod 1 (Ground, Influence-Fired)

Overall length (w/ parachute pack): 68.5 inches
Overall length (w/o parachute pack): 64.5 inches

Diameter:
-Case: 18.625 inches
-Tail section: 15.75 inches
-Parachute pack: 18.5 inches

Filling: TNT
Weight of filling: 465 pounds
Total weight: 1,000 pounds
Charge/weight ratio: 46.5%
Negative buoyancy: 400 pounds

or

Filling: Torpex
 Weight of filling: 525 pounds
Total weight: 1,060 pounds
Charge/weight ratio: 49.5%
Negative buoyancy: 460 pounds


Construction: The 1,000-pound Aircraft Mine AN-Mk 26 Mod 1 consists of a cylindrical steel case welded with hemispherical nose and tapered tail section.  The tail is closed by a concave cover secured with cap screws.  A ring for mounting the parachute assembly is welded around the after end of the case.  The Tail Parachute Pack Mk 1, containing Parachute Mk 2, is fitted to the tail when the mine is installed in plane.  This parachute slows the fall of the mine through the air to lessen the shock of water impact, and is released from the case on striking water by an impact release mechanism.  Suspension is horizontal, two standard lugs being welded onto the body 14 inches apart and placed 90 degrees from the side pockets.

There is a removable British single-suspension lug 180 degrees removed.


Markings: Black overall


Remarks:
-Normal Use: As ground, magnetic induction mine.  Aircraft-laid, with parachute (release altitude - 200 feet or higher).  Laid offensively in depths of water from 16 feet to 120 feet against surface craft, and up to 500 feet against submarines.  Extender and clock starter are caused to function by hydrostatic pressure at depths of 16 feet or greater.  Clock delay runs off in 170 minutes to arm the mine.

-Use as bomb: This mine is poorly suited for use as a bomb, since accurate dropping by parachute is difficult; and if parachute is not used, the case tumbles.  Fuzes require longer air travel to arm than usual, because of the shape of the mine and the manner of fall through the air.






20-pound Frag. AN-M41, and AN-M41A1

Overall length: 19.5 inches
Body length: 11.3 inches
Body diameter: 3.6 inches
Wall thickness: 0.56 inches
Tail length: 9.26 inches
Tail width: 5.1 inches
Tail weight: 1.6 pounds

Filling: TNT
Weight of filling: 2.7 pounds
Total weight: 20.3 pounds
Charge/weight ratio: 13%



Body construction: This bomb is constructed of cast-steel nose and tail pieces, a seamless steel inner tube, and a helically-wrapped drawn steel wire wrapping around the inner tube.  The tube is threaded to hold the nose and tail sections.


Suspension: For individual suspension of this bomb, a U-shaped eyebolt of steel is welded to the body at the center of gravity for horizontal suspension, and an eyebolt is welded to the tail for vertical suspension.

The bomb may be dropped in a cluster of six bombs in the Cluster Adapter AN-M1A2 or M1, forming the Cluster AN-M1A1 or M1.  The cluster adapter is made of sheet steel, and does not use eyebolts of bombs for suspension.


Tail construction: Four rectangular sheet-steel vanes are welded to a length of one-inch cast-iron pipe which screws into the base filling plug.


Remarks: This bomb is a high-level fragmentation bomb and should be dropped from a minimum altitude of 400 feet.

The A1 modification of this bomb consists of adding a 1 and 1/2-inch shoulder around the nose to facilitate clustering with unfuzed bombs.  Heretofore, the spacers of the cluster adapter have fitted against the fuze, thereby making it requisite that the bombs be clustered and shipped with fuzes inserted.








23-pound Para-Frag. AN-M40, AN-M40A1, M72, and M72A1

Overall length: 26.7 inches
Body length: 11.3 inches
Body diameter: 3.6 inches
Wall thickness: 0.56 inches
Tail length: 13.9 inches
Tail width: 4.35 inches
Tail weight: 5.3 pounds

Filling: TNT
Weight of filling: 2.7 pounds
Total weight: 24.5 pounds
Charge/weight ratio: 11%



Body construction: These bombs are constructed of cast-steel nose and tail pieces, a seamless steel inner tube, and a helically-wrapped drawn steel wire wrapping around the inner tube.  The tube is threaded to hold the nose and tail sections.


Suspension: For individual suspension of these bombs, a U-shaped eyebolt of steel is welded to bomb at the center of gravity.

The 23-pound Para.-Frag. Bombs AN-M40 are always clustered, three of the bombs with the Cluster Adapter AN-M3 forming the Cluster AN-M4.

The 23-pound Para.-Frag. Bomb M72 is a slightly modified version of the AN-M40.  It is adapter for individual suspension and can be carried in vertical cellular racks by several types of Army planes.


Tail construction: The 23-pound Para.-Frag. Bombs AN-M40 and M72 are fitted with cylindrical sheet-steel parachute housings which have end caps at the rear end and contain a white silk parachute.  The Parachute Unit M3 is used in the Para.-Frag. Bombs AN-M40 and AN-M40A1; the Parachute Unit M4 in the Para.-Frag. Bombs M72 and M72A1.


Remarks:  The AN-M40 and M72 are low-level fragmentation bombs and should be dropped from a maximum altitude of 400 feet.


The A1 modification of these bombs consists of adding 1 and 1/2-inch shoulder around the nose of the bomb to facilitate clustering with unfuzed bombs.  Heretofore, the spacers of the cluster adapters have fitted against the fuze, thereby making it requisite that the bombs be clustered and shipped with the fuzes inserted.  Bombs with this modification are designated the 23-pound Para.-Frag. Bombs AN-M40A1 and M72A1.






Fragmentation clusters and cluster adapters



Cluster AN-M1A1, Cluster Adapter AN-M1A2: This cluster, consisting of the Cluster Adapter AN-M1A2 or M1 and six Fragmentation Bombs AN-M41, is made of sheet metal and does not use eyebolts for suspension.


Cluster AN-M1A2, Cluster Adapter AN-M1A3: With the modification of Fragmentation Bombs AN-M41 to permit fuzing in the field, the following changes are made in the Cluster Adapter AN-M1A2: (1) flat springs are substituted for the fuze lock plates; and (2) the suspension lugs are changed from a strip type to a type similar to those on G.P. bombs.  The new lugs were designed to permit suspension of the clusters in all existing types of bomb racks.  The modified cluster adapter becomes the AN-M1A3, forming, with six Fragmentation Bombs AN-M41A1, the Cluster AN-M1A2.

If the modified Cluster Adapter AN-M1A3 is used with unmodified Fragmentation Bombs is used with modified Fragmentation Bombs AN-M41; or the unmodified Cluster AN-M1A1 is used with modified Fragmentation Bombs AN-M41A1; or the unmodified Cluster Adapter AN-M1A1 is used with unmodified Fragmentation Bombs AN-M41, no change will be made in the designation of the Cluster AN-M1A1.  The bombs, in these latter cases, will be fuzed when the bombs are clustered at the loading plant.

The unmodified Fragmentation Bomb AN-M41 with Cluster Adapter AN-M1A1 is not suitable for Navy use.  The modified Adapter AN-M1A2 can be used, and the cluster is designated S1ZVL.


Cluster AN-M4, Cluster Adapter AN-M3: The cluster Adapter AN-M3 and three Fragmentation Bombs AN-M40 form the Clsuter AN-M4.


Cluster AN-M4A1, Cluster Adapter AN-M3: When Para.-Frag. Bombs AN-M40A1 are clustered, the Cluster Adapter AN-M3 is still used without any alteration in design, but the designation of the cluster is AN-M4A1.


Cluster M26, Cluster Adapter M13: The Fragmentation Bomb Cluster M26 consists of a Cluster Adapter M13 to which are secured twenty 20-pound Fragmentation Bombs AN-M41A1, in two groups of ten.  The cluster is 53 and 1/2-inches long, 14 and 11/16-inches wide, and 13 and 3/4-inches high.  The cluster adapter is a steel framework consisting of a tubular suspension bar to which the suspension lugs are fitted, steel separator plates, and two metal straps secured by release buckles.  The separator plates located before each group of the bombs are built with arming vane stops for the Nose Fuzes M110A1 used in the individual bombs.  The cluster can be adapter for either quick or delayed opening.

Quick opening is accomplished by the arming wires, which are fed through the release buckles and are withdrawn on the release of the cluster from the plane.   In delayed opening, a Mechanism Time Nose Fuze M155 (T71) or M1111A2 is screwed to the fuze adapter in the forward end of the tubular suspension bar.  When the fuze detonates at the preset delay, the explosion drives a steel slug rearward to cut the shear wires in both the forward and the after release buckles, thereby permitting the cluster to open.

Tumbling of the Cluster M26 prevents the Nose Fuze M111A2 from arming correctly, and therefore the fuze has been modified by the substitution of an anemometer-type arming vane for the standard vane.  So modified, the fuze is known as the T77.  Modification can be accomplished in the field by kits now being issued.








220-, 260-pound Frag. AN-M88 (220-lb) and AN-M81 (260-lb)

AN-M81
Overall length: 43.7 inches
Body length: 32.8 inches
Body diameter: 8 inches
Wall thickness: 1 inch
Tail length: 11 inches
Tail width: 11.5 inches
Tail weight: 4.1 pounds

Filling: Composition B
Weight of filling: 34.1 pounds
Total weight: 260 pounds
Charge/Weight ratio: 14%



AN-M88
Overall length: 43.7 inches
Body length: 32.8 inches
Body diameter: 8 inches
Wall thickness: 1.25 inches
Tail length: 11 inches
Tail width: 11.5 inches
Tail weight: 4.1 pounds

Filling: Composition B
Weight of filling: 46.9 pounds
Total weight: 216.17 pounds
Charge/Weight ratio: 21.6%


Construction: The Fragmentation Bomb AN-M88 differs from the M81 only in that it has a 0.75-inch steel coil steel coil around the body instead of the one-inch coil.  Both bombs are constructed in these two ways.  In initial production, nose and tail pieces are of cast-steel construction and screw onto a central section of seamless steel tubing.  A square helical steel spring is wound around the steel tubing.  The nose and tail pieces are partially cut through to afford greater fragmentation (this is similar to the M82, except for the provision for tail fuzes and the Auxiliary Booster M104 in the larger bombs).  The majorite of AN-M88's and M81's however, have a one-piece steel tubing, and the helical steel spring is wound around the steel tubing, for the entire length of the body.

Suspension is horizontal; two eyebolts are welded to body along the longitudinal axis of the bomb, 14 inches apart.  A third eyebolt is welded to the body at the center of gravity 180 degrees removed from the other eyebolts.  The tail is the normal box type, secured to the bomb by a locking ring.


Remarks: The initial bombs were filled with TNT; later productions are filled with Composition B with TNT surrounds.

Present production of these bombs does not include Auxiliary Booster M104, as this was found unnecessary.

Next Time: Army Experimental Types, and Introduction for Chemical, Incendiary, and Smoke Bombs