British Explosive Ordnance - Cluster Projectiles Part 1

British Explosive Ordnance

  

Cluster Projectiles Introduction

   

A cluster projectile is an assemblage of small bombs or flares held together primarily by resilient straps and beams.  It is constructed so as to be an amiable projectile, and is usually fitted with a tail unit for purposes of stabilization.

At present there are cluster projectiles for flares, incendiary bombs, smoke bombs, and small fragmentation bombs.  The cluster projectiles are rapidly replacing the Small Bomb containers as the preferred method for carrying small bombs and flares.  Advantages of the cluster projectile include ease of loading and installation in the aircraft, increased number of bombs or flares contained in the same space, and increased accuracy.

A new and improved type of cluster, called the Nose Ejection Cluster, was put into production just before the end of World War II.  These clusters are discussed in general at the end of this chapter, and available details listed in tabular form.

Fuzes are incorporated in the cluster projectiles to disintegrate the cluster itself and so permit the individuals bombs or flares to disperse and fall freely.  Cluster projectiles have explosive channels and pellets so designed as to break up the cluster without injuring any of the contained bombs.  Flare and incendiary clusters are fuzed either at the nose or at the tail, while fragmentation and smoke bomb clusters now in service are fuzed in the tail only.   Nose ejection clusters are tail fuzed only and use two tail fuzes to insure functioning.

The bombs or flares are usually shipped already packed in the cluster projectile, so that assembly of the complete round is not necessary in the field.  The fuze of the cluster is generally installed just prior to loading the projectile on the aircraft.

Cluster Projectile 270lb No.1 Mk I (Service)

Contents: Seven 4.5-inch flares
Overall length: 62.75 inches
Body diameter: 18 inches
Total weight: 260 pounds

Fuzing: Nose Fuze No.42, 848, 849, or 860 Mk II
Tail No.: No.69 Mk I
  

Color and markings: Dark green overall

  

Description: The cluster is a cylindrical metal container consisting of a nose unit, recessed to receive the noses of seven 4.5-inch reconnaissance flares, and a fuze adapter, from which radiate six flash tubes to the flare igniters and three flash channels leading to the explosive pellets in the piston housings.  The nose unit is secured to the panel locating plate and the tail plate by the T-section suspension bar and the clamping bars.  The clamping bars consist of a bar to which are welded two panels.  The clamping bars locate the panels and are secured through the panel locating plates to the tail plate and to the nose unit by spring washers and nuts.  The nuts securing the clamping bars to the piston housings are further secured by split pins.  The tail tie rod is screwed into the tail plate and the tail unit fastened to it by a spring washer and nut.

The flares, from which the suspension lugs and domed caps have been removed, are located by the recesses in the nose unit and panel locating plate.  The flares are fuzed with special igniters, consisting of the body and dome portion of the Fuze No.42 without the percussion cap and striker mechanism, and sealed with primed cambric.
 

Tail Construction: The Tail No.69 Mk I consists of a sheet-metal tail cone to which a cylindrical strut is attached by four fins.  The tail unit is attached to the tail plate of the cluster by a tie rod, which passes down the center axis of the tail wire.


Functioning: On release from the aircraft, the cluster falls normally until the fuze functions.  When the fuze functions, the flash from the magazine passes through the flash tubes to ignite the igniters in the nose of each flare, and through the flash channels to explode the gunpowder pellets in the piston housings.  The explosion of the pellets forces the pistons out of their housings, causing the clamping bars to swing outwards, thus releasing the nose unit, panels, and initiated flares.  The flares then function in the normal manner.


Suspension: The cluster is suspended by a single lug secured to a T-section suspension bar, which runs from the nose to the base of the cluster.

 

Cluster Projectile 140lb No.2 Mk I (Service)
   

Contents: Four 4.5-inch flares
Overall length: 53.25 inches
Body diameter: 12.35 inches
Total weight: 140 pounds (approx.)

Fuzing: Nose Fuze No. 848, 849, or 860 Mk II
Tail No.: No.70 Mk I

  

Color and markings: Dark green overall

  

Description: This cluster is designed to hold four 4.5-inch flares.  The components of the cluster consist of a nose unit, four flat caps which replace the dome-shaped tail closing caps of the flares, a T-bar, a panel locating plate, a tail plate, two clamping bars, two panels, and a tail unit.

When the cluster projectile is assembled, the four flares are located between the nose unit and the panel locating plate, and the assembly is held together by the clamping bars.  The tail plate is also retained in position by the clamping bars, and the tail unit is secured to the tail plate by a nut and washers fitted to one end of a tie-rod, whose other end is screwed into the tail plate.  The panels enclose the flares, and the T-bar, which positions the panel locating plate and the tail plate relative to the nose unit, carries a suspension lug by which the cluster projectile is attached to a bomb carrier.


Tail Construction: Tail Unit No.70 Mk I consists of a shortened tail cone, the base of which fits over the rim of the tail plate, and a tail strut secured to the tail cone by four fins.  The tail unit is attached to the tail plate of the cluster by a tie-rod which passes down the center axis of the tail cone.


Functioning: The fuzed cluster projectile is released from the aircraft, and the fuze is set in operation.  When the gunpowder in the fuze magazine explodes, the flash ignites the gunpowder contained in the small bag in the fuze adapter of the nose unit.  The boosted flash passes through the six flash tubes, initiates the igniters fitted to the four flares, and fires the gunpowder in the piston housings.

The gases formed by the ignition of the gunpowder in the piston housings force the pistons out of the housings, shearing the brass shear pins, and so causing the clamping bars to swing outward on the U-bolts.  This outward movement of the clamping bars releases the nose unit, the panels, and the initiated flares.  The parts of the disintegrated cluster fall separately, and the flares, initiated by their igniters, function in the normal manner.


Suspension: This cluster is designed for suspension in British aircraft only.  A single suspension lug is fitted to the T-bar of the cluster.


Remarks: In addition to normal stencilling in English, propaganda messages in German are stencilled in white paint on the sides of the panels.

Cluster Projectiles 400lb No.3 Mk I (Service)
  

Contents: Four 7-inch hooded flares
Overall length: 72.5 inches
Body diameter: 18 inches
Total weight: 400 pounds 

Fuzing: Nose Fuze No. 860

  

Color and markings: Black overall

  

Description: The cluster projectile consists of a flare-supporting unit, heavy nose, half securing bands, and the hooded flares.  The flare supporting unit consists of a square cast-iron plate, on which is painted a narrow white alignment strip, and a steel tube to which is welded a suspension web.  The rear end of the tube is flanged, and four equispaced pins are riveted to the flange.  External threads on the fuze housing receive the plate-securing ring, which secures the plate to the tube.  The tube is also internally threaded at the nose end to receive the fuze and a centrally drilled separating plug.

Four flash channels are drilled through the walls of the fuze housing immediately above the separating plug.  Four flash tubes lead from these flash channels to the four equispaced holes in the plate drilled to receive the flare igniters.  The piston, flanged at the protruding tail end, is housed in the tube and retained in position at the nose end by two shear pins.  A space between the nose end of the piston and the centrally drilled separating plug forms a burster chamber, which is filled with a small fabric bag containing 80 grams of gunpowder when the cluster is fuzed.  The heavy cast-iron nose, on which is painted a white alignment strip, and to which the flare supporting unit is bolted, is slotted to receive the flash tubes and the Fuze No.860.  The nose end plate is retained in position by the fuze.  The four flares are fitted with special igniters instead of fuzes, and are retained in position in the cluster by half securing bands.  The igniters are located in the drilled hole in the plate.

The four half securing bands of the flare securing unit are seated on the flange, and each is retained in position by a socket, welded to the outside of the band, engaging with a corresponding dowel pin.  The sockets are covered by metal bridges in which are cut horizontal slots to receive the flange of the piston.  This prevents premature displacement of the flares.  The four remaining half securing bands are placed in position round the flares and bolted to the other half bands.  A cruciform distance piece is bolted to the tail end of the piston.


Functioning: On release from the aircraft, the cluster falls in a normal manner until the fuze functions.  The flash from the fuze magazine passes through the flash channels and the flash tubes to activate the igniters, and through the separating plug to the burster charge.  The explosion of the burster charge forces the piston towards the tail end of the cluster to sever the shear pins and to lift the half securing bands off the dowel pins by means of the flange of the piston engaging in the bridges.  The four flares are thus lifted off the plate of the flare supporting unit.  A three-second delay in the flare igniters allows the cluster to disintegrate before the flares function.

 

Cluster Projectile 500lb No.4 Mk I (Service)

Contents: Fourteen 30lb Type J incendiary bombs
Overall length: 72.5 inches
Body diameter: 18 inches
Total weight: 400 pounds 

Fuzing: Tail Fuze No.867 Mk I or No.885 Mk I
Tail No.: No.44 Mk I or II

  

Color and markings: Dull red overall, one of the tensioning straps painted bright red.

  

Description: This cluster is hexagonal in shape, and contains fourteen 30lb type "J" incendiaries, in two fagots of seven bombs each.  The bombs are placed nose-to-nose and arranged in super-imposed rows of 2, 3, and 2 in each fagot.  The bombs are retained in position by the front and rear end plates, the top and bottom beams, the side fairings, tensioning straps, and the retaining bar.  The front and rear end plates secure the spring-loaded covers of the bomb parasheet containers.  Lateral pins on the retaining bar engage with and hold the tabs of the tensioning straps in position.  A shear wire near the end plate acts as a safety device for the retaining bar.  To the rear end of the retaining bar is secured a pivoted lever, the lower end of which engages with the piston in the fuze adapter.

The fuze adapter is fixed to the channel plate, which in turn is fastened to the rear end plate.  A nut, welded to the center of the rear end plate, received the tail tie rod to which the tail unit is secured by a tension nut.  A nose fairing is secured to the front end plate, and fairing are fitted to the top beam.  The fairing adjoining the rear end plate is slotted to receive the fuzing lanyard of the fuze and the safety wire of the tail unit.


Tail Construction: The Tail Unit No.44 Mk I is located by two dowel pins and is provided with two inspection windows to ensure correct alignment of the arming forks.  A tie rod connects the tail unit to the cluster.


Functioning: On release from the aircraft, the fuze-setting control link withdraws the safety wire from the tail unit and, at the same time, breaks the shear wire of the fuze by means of the fuzing lanyard.  The cluster falls normally until the fuze functions.  The explosion of the fuze magazine forces the piston forward in its housing to cause a rocking movement of the pivoted lever.  The sudden movement of the pivoted lever exerts a pull on the retaining bar to break its shear wire and disengage the lateral pins from the tabs of the tensioning straps.  The straps, thus released, fly outwards to release the 14 bombs, which function normally on impact.


Suspension: A single suspension lug is fitted to the top beam, and tapped holes are also provided for the fitting of American lugs where necessary.


Remarks: This cluster projectile is designed to replace the Small Bomb Container as a means of carrying 30lb type "J" incendiaries.

Cluster Projectile 500lb No.6 Mks I and II (Service)
  

Contents: Ninety 4lb smoke bombs
Overall length: 72 inches
Width across flats: 16 inches
Tail length: 27 inches
Tail width: 16 inches
Total weight: 428 pounds 

Fuzing: Tail Fuze No.885 Mk I
Tail No.: No.45 Mk I

  

Color and markings: Dark green overall

  

Description: The cluster is hexagonal in cross section and comprises ninety 4lb smoke bombs, arranged in five fagots of eighteen bombs each.  The bombs are arranged nose-to-tail longitudinally, and in alternate rows the bomb fuzes point in opposite directions.  The bombs are held in place by a front end plate and a rear end plate, a top beam and a bottom beam, four side plates, tensioning straps, and a retaining bar.  Lateral pins on the retaining bar engage tabs forming part of shoes attached to the ends of the tensioning straps.  A shear wire passes through the retaining bar and a bridge on the top beam.  The four side plates, together with the two beams, completely surround the bomb cluster.  A channel secured to the rear end plate supports a fuze adapter, the outer end of which is closed by a transit plug and leather washer.  Inside the adapter is a piston through which is a pin to engage the lower end of a pivoted lever.  The fuze adapter and piston are slotted to receive the lever, which is connected at its upper end to the retaining bar.

The rear end plate has two dowels for locating the tail in position, and a nut welded to the center of the plate receives one end of a tail tie rod when the tail unit is fitted to the cluster.  The front end plate has two dowels for locating a nose cover in position.  A securing bolt is screwed into the center of the nose end plate to receive a fixing nut, when the nose cover is fitted to the cluster.


Tail Construction: The tail unit consists of a tail cone with an approximately hexagonal base, and a tail strut secured to the cone by fins.  A the base of the tail cone are two holes to fit over the dowels on the rear end plate of the cluster.  A tie rod passes through the center of the tail, and one end of this rod is threaded to screw into the central nut on the rear end plate.  The other end of the rod is fitted with a tensioning nut for securing the tail to the cluster.  The tail unit also has an arming spindle mounted in bearings, which has a fork at its inner end and an arming vane at its outer end.  The safety wire, when fitted, passes through holes in a bracket, a projection on the support for the arming spindle bearings, and a blade of the arming vane.  Two inspection windows in the tail cone are provided to enable the armorer to watch the fork of the arming spindle, when fitting the tail unit.


Functioning: When a cluster projectile fuzed with a Fuze No.867 is released, safety wire is withdrawn from the tail-unit arming vane and the shear wire of the fuze is broken to release the fuze safety pin.  After a period of delay during which the cluster projectile falls freely, the fuze magazine is fired.  The products of combustion of the magazine charge force the piston in the fuze adapter against the lower end of the pivoted lever, which is thus rocked about its pivot and exerts a pull on the retaining bar of the cluster.  The pull breaks the shear wire passing through the retaining bar, and moves the bar so that its pins disengage the tabs on the shoes attached to the tensioning straps.  The straps then fly outwards and the cluster disintegrates, its component parts falling away separately.  The individual bombs function on impact.


Suspension: A British type suspension lug is fitted to the top beam of the cluster, and tapped holes are provided for fitting American type lugs.


Remarks: The Cluster Mk I contains 90 4lb Smoke Bombs Mk III.  The Cluster Mk II is identical to the Mk I, except that it contains 90 4lb Smoke Bombs Mk II** or Mk IV.

If the smoke composition used in the 4lb smoke bombs gets wet, and especially if wetted by sea water, it is liable to spontaneous combustion through chemical action.

Cluster Projectile 500lb No.7 Mk I (Service)

Contents: Fifty-six 8lb F. Bombs Mk II
Overall length: 67 inches
Body diameter: 15 inches
Tail length: 27.75 inches
Tail width: 18 inches
Total weight: 550 pounds 

Fuzing: Tail Fuze No.885 Mk I
Tail No.: No.46 Mk II

  

Color and markings: Dark green overall, one tensioning strap painted red.

  

Description: This cluster consist of eight fagots of seven 8lb F. bombs each.  The fagots are retained by top and bottom beams, front and rear end plates, side fairings, and four tensioning straps.  The tensioning straps are held by lateral pegs on the release rod, which is located in the top beam.  The release rod is connected to a level and piston mechanism, the cylinder of which also serves as the adapter for the barometric fuze and is located on the rear end plate.  Before the fuze is fitted, the adapter is closed by the inverted cup portion of the safety device for the release mechanism.

To convert the cluster into an amiable cluster, a blunt nose fairing and drum-type tail are fitted to the front and rear end plates, respectively.  A special streamlined nose fairing is provided for use when the cluster is to be stowed externally on the plane.
 

Functioning: On release from the aircraft, the cluster falls until the fuze functions.  The explosion of the magazine forces the piston forward in its housing and causes a rocking motion of the pivoted lever.  The sudden movement of the lever exerts a pull on the retaining bar and breaks the shear wire, disengaging the lateral pins from the tabs of the tensioning straps.  The straps are thus released and fly outwards, releasing the contained bombs.

Next Time: Cluster Projectiles Part 2

British Explosive Ordnance - Incendiary, Smoke, and Light-Case (Chemical) Bombs

British Explosive Ordnance

Incendiary Bombs Introduction





Incendiary bombs of many various types, ranging in weight from 4 to 250 pounds, are at present in service use for operations against different types of targets.  The construction and filling of these bombs differ with the individual types, and no general description can be given here to cover the complete range.

Some bombs, such as the 4 pound series, have bodies composed mainly of incendiary material, such as magnesium alloy, and are filled with solid incendiary compositions.  Other bombs, such as the 30 pound IB, have steel tubular bodies and are liquid filled with a rubber/benzole solution, or may be partially filled with cast white phosphorus.  Liquid-filled bombs are provided with an ejection charge.  The obsolete 25 pound bomb has a faired steel tubular body containing incendiary firepots which are ejected successively by small gunpowder charges.

A small percentage of 4 pound incendiary bombs contain an explosive charge, the object of which is to render dangerous approach to the burning bombs, because of the risk of flying splinters.  Attempts to extinguish these and standard non-explosive bombs, which are dropped simultaneously, are thereby discouraged.  If the explosive charge is gunpowder, the bomb is distinguished by the letter "E".  A tetryl (CE) explosive charge is indicated by the letter "X".

These bombs are either painted a dull red overall, or have the nose end painted red for several inches.  Most of them have two black bands separated by a bright red band around the nose end.  Though formerly carried in the 250lb Small Bomb Container, Cluster Projectiles (amiable clusters) are replacing the SBC as the favored method of carrying.









IB 4lb Mks I, IE, II, IIE, III, and IIIE, and 4lb "X" with 2- and 4-minute delays, Mk I  (Obsolescent)

Overall length: 21.4 inches
Width across flats: 1.67 inches (hexagonal in shape)

Total weight: 4 pounds (approx.)

Fuzing: Integral simple impact striker
  

Color and markings: 
Mks I-III: Dull red nose, with two 1/2-inch black bands separated by 1/2-inch bright red band around nose.

Mks IE-IIIE: Bright red tail base and addition 1/2-inch bright red band 1/2-inch abaft dull red nose.

  

Body Construction: The Bomb Mk III consists of a hollow, magnesium-alloy body, at one end of which is a cast iron or steel nose: the body being cast onto the nose during manufacturing.  A magnesium-alloy tail plug, which may be of solid or open construction, is screwed into the other end of the body.  Fixed to the tail plug by two drive-screws is a tin-plate tail closed by a tail cap.

The tail plug houses a striker, creep spring, ferrule having four tabs, and a brass cap holder containing a 1.7 grain detonator.  When the bomb is packed in its case, movement of the striker towards the detonator is prevented by a spring-loaded safety plunger housed in a sleeve fitted into the tail plug.  Two vent holes, plugged by cork inserts, are provided in the body to communicate with the space between the cap holder and the filling of the bomb.  A strip of primed cambric is located in this space.  The Mk IIIE is identical to the Mk III, except for a black powder exploder charge, just abaft the nose plug in the body cavity, which replaces a small quantity of the thermite filler.


Functioning: When the bomb is released, the safety plunger springs out.  On impact, the striker overcomes the resistance of the creep spring, bends the tabs on the striker support (brass cross), and strikes and fires the detonator.  The products of combustion from the detonator blow the cork inserts out of the vent holes.  The flash from the detonator is conveyed by the primed cambric strip to the priming paste (gunpowder-shellac paste) on the inside of the washer, which ignites the pressed priming composition and in turn the thermite pellets.  The magnesium-alloy body starts to melt about 25 seconds after the bomb is ignited, and burns for about 10 minutes.  In the Bomb Mk IIIE, after 1 and 1/2 to 4 minutes, the powder in the burster is ignited and explodes.


Suspension: The bombs are carried in the Small Bomb Container, or in a Cluster Projectile.


Filling: The bombs are filled with thermite incendiary pellets and the priming pellets which ignite them.  The incendiary material from which the bodies are manufactured, a magnesium alloy, also contributes to the incendiary effect.  The "E" bombs have an added black powder burster charge, while the "X" bombs have a CE burster charge.


Remarks: The IB 4lb Mks II and IIE are similar to the Mk III and Mk IIIE, but have the following differences.  The bomb bodies have a smaller bored, and the bomb bodies have four cork-plugged vent holes.  The tail plugs and cap holders are of solid magnesium alloy, and the noses are of steel.

The 4lb Bombs Mk I and IE are similar to the Mks II and IIE respectively, but have only a 1.62 grain detonator and are 21.4 inches long.

The 4lb X, with 2- and 4-minute delays, Mk I is similar in construction to the Mk III, except that a CE exploder is contained in the steel nose plug; this exploder being initiated after delay of either two or four minutes.  The letter "X" is stamped on the outside followed by a number "2" or "4" indicating which delay is incorporated in the bomb.  The marking bands are the same as on the Mk IIIE, except that the red band between the two black bands is 1 inch wide instead of 1/2 inch, and the base of the tail is not painted red.

IB 4lb Mks IV, IVE, V, VE, and 4lb "X" with 2- and 4-minute delays, Mk II  (Service)

Overall length: 21.4 inches
Width across flats: 1.67 inches (hexagonal in shape)

Total weight: 4 pounds (approx.)

Fuzing: Integral simple impact striker
  

Color and markings: End face of nose, and body abaft nose for 2 inches painted bright red; Mk IVE has 1/2-inch bright red band 1/2-inch abaft bright red nose coloring.

  

Body Construction: The Bomb Mk IV is hexagonal in shape, having a hollow magnesium-alloy body, and a cast iron nose, with the body cast to the nose in manufacture.  A tin-plate tail, closed by a tail cover, is secured to the other end of the body by three drive-screws, which also hold a steel striker housing in position in the body.

At the tail end, the body is counter-bored to accommodate an igniting mechanism consisting of a striker, located in the striker housing, and a steel plate seated at the bottom of the counter-bore and containing a 1.7 grain detonator.  One end of the striker is pointed, and the other end projects through a hole in the striker housing.  The edge of this hole is chamfered to permit a thin brass cross, secured to the striker, to be bent and pulled through the hole when the bomb functions.  This cross forms a striker support during transit and storage.  Movement of the striker towards the detonator is, when the bomb is packed in its case, prevented by a spring-loaded safety plunger housed in a sleeve.  Two vent holes, plugged by cork inserts, are provided in the tail end of the body and communicate with the space between the igniter mechanism and the bomb main filling.  A strip of primed cambric is located in this space.  The Mk IVE is identical to the Mark IV except for a black powder burster charge just abaft the nose plug in the body cavity, which replaces a small quantity of the thermite filler.


Functioning: When the bomb is released from the container, the safety plunger springs out, and, on impact with the target, the striker moves down, breaking free from the brass cross striker support and firing the detonator.  The flash from the detonator ignites the primed cambric strip and the priming paste (gunpowder-shellac paste), and the products of combustion blow the cork inserts out of the ventholes.  The paste ignited the pressed priming composition which, in turn, ignites the thermite pellets.  The magnesium-alloy body starts to melt about 25 seconds after the bomb is ignited, and burns for about 10 minutes.  In the Bomb Mk IVE, after 1 and 1/2 to 4 minutes, the gunpowder in the burster is ignited and explodes.


Suspension: These incendiaries are carried in the Small Bomb Container, or in a Cluster Projectile.

Filling: The bombs are filled with thermite incendiary pellets and the priming pellets which ignite them.  The incendiary material from which the bodies are manufactured, a magnesium alloy, also contributes to the incendiary effect.  The "E" bombs have an added black powder burster charge, while the "X" bombs have a CE burster charge.


Remarks: The IB 4lb Mks V and VE are similar to the Mk IV and Mk IVE, except for the following differences.  The bomb is initiated by a cap and anvil being struck by the striker, the striker having a blunt point.  The cap is supported by an aluminum plate, and the striker housing is made of aluminum.  A different kind of pressed priming composition is used, which is more violent than the priming compositions used in the Bomb Mk IV, and causes some of the magnesium alloy to scatter when the bombs are ignited.  This bomb is actually the US AN-M50.

The 4lb X, with 2- and 4-minute delays, Mk II is similar in construction to the Mk IV, except that a CE exploder is contained in the steel nose; this exploder being initiated after delay of either two or four minutes.  The nose is painted dull red, for 3 and 1/2 inches, with two 1/2-inch black bands separated by a 1-inch bright red band painted on the nose.  A second bright red band, 1/2-inch wide and 1/2 inches abaft the dull red coloring, indicates that the incendiary is of the explosive type.

No "E" marks are now produced.  The small black powder charge was not lethal, but served only as a deterrent.

IB 30lb Mks I, II, and IIM (Obsolete), and III, IIIM, IV, and IVM (Service)
   

Overall length: 32.7 inches

Body length: 18 inches

Body diameter: 5 inches

 Wall thickness: 0.1 inches

 Tail diameter: 4.7 inches

Tail length: 14.2 inches

Total weight: 25 pounds

Fuzing:
Mk I: Nose Fuze No.38
Mks II-IV: Nose Fuze No.846

Tail No: No.40 Mk I

Color and markings: All marks dull red overall;
Mk I: One bright red band around nose
Mks II-III: Two bright red bands, one around the nose and one around the rear of the body.
   

Description: The bomb consists of a cylindrical body, with a hemispherical nose at one end and a tail at the other: the cylindrical tail strut being connected by four equi-spaced fins to the rear end of the tail cone.

The cylindrical body is made from welded tube, the forward end of which is reduced slightly to fit into the rim of the hemispherical steel-plate nose to which it is welded.  The nose is pierced centrally and has a burster container welded into it and closed by a screwed plug, the outer surface of which conforms with the shape of the bomb nose.  A flanged tail plate is welded in the rear end of the body, and has a hollow spigot through which the bomb is charged in the center.

The spigot is closed by a screwed plug, and is threaded externally for the attachment of the tail.  Riveted in the forward end of the tail cone is a diaphragm plate having a threaded boss, which screws onto the tail plate spigot to secure the tail to the bomb body.  A 10 percent air space is left in the body when it is filled.  A 3-inch wide cylindrical strut is attached to the rear of the tail cone by four fins spot welded to both strut and cone.  The tail cone is closed by an end cap.

Functioning: On impact, the firing of the gunpowder in the magazine of the fuze disrupts the bomb body along the weld, and scatters the filling over a considerable area to produce a large number of fires.


Suspension: The bombs are carried in a Small Bomb Container, or suspended from a bomb carrier by a lug on a suspension band. SBC 250 will carry eight bombs.
  

Filling: One pound white phosphorus, and seven pounds rubber-benzole or Perspex-benzole solution.


Remarks: The 30lb Bomb Mk I is similar to the Mk IV except for the following differences.  The burster container is screwed and welded into a flat nose plug, which is welded into the end of the body, and a hemispherical nose fairing fits onto the nose plug.  The bomb employs the Nose Fuze No.38, and is filled with 1.5lb of white phosphorus cast in the nose end of the body and approximately 6lb of a 5 percent solution of rubber in benzole.

The 30lb Bomb Mk II is similar to the Mk IV, except that the body is made from drawn tube instead of being a welded tube; so the bomb functions by tail ejection of the filling; the tail plate and tail being blown off by the firing of the magazine charge in the fuze.  The weight of white phosphorus case in the nose is 1.5 pounds.

The Mk III is similar to the Mk IV, except that the body is of heavier gauge metal.

The Mk IIIM is similar to the Mk III, except that the body has two external pads to locate a suspension band with a lug, which may or may not be used.

The Mk IVM differs from the Mk IV only in that it has a suspension band with a lug.
 

IB 30lb Type J Mk I (Service)
    

Overall length: 21 inches
Body diameter: 5.5 inches

Total weight: 31 pounds
 Wt. Thermite: 1 pound
Burning time: 1 minute (approx.)

Fuzing: Integral simple impact striker.

Tail No: No.36 Mk I

Color and markings: Dull red overall,
two 1-inch bright red bands around body,
stencilled in black on one band are letters "CTF" and on other "OCC".

  

Description: The bomb consists of a cylindrical steel body with a dished steel nose plate having a central spigot welded on, a steel ring welded to the nose plate, and a wooden nose covered by a thin metal cap and secured by screws to the ring.  A tail plate is welded, near the other end of the body, and a steel central tube, projecting through the tail plate, is welded to the tail plate and the spigot on the nose plate.  A magnesium-alloy striker is screwed to the central tube and retains a detonator holder in position.  The striker is supported by a two-armed brass cross which engages the top of the housing.  A spring-loaded safety plunger, contained in a sleeve, projects into the path of the striker.  The safety plunger is held in position by a retaining sleeve, which is secured to the parasheet container.

An automatic valve is fitted to the tail plate and has an auto-valve body screwed into a socket welded into the tail plate.  A tube extension, screwed into the inner end of the auto-valve body, holds a flexible tube, which extends to within three inches of the bottom of the bomb.  A jet having its outlet hole pointing vertically out of the tail is screwed into the side of the auto-valve body.  The valve chamber houses a spring-loaded piston having a rubber sealing disk at its inner end, which normally seals the central hole in the valve body.

The parasheet is housed in a container held in the tail end of the bomb body by six retaining screws, and its rigging lines are anchored to the container.  The container is closed by a loose metal cover held in position by the end plates of the cluster projectile.  A safety pin retaining sleeve, secured to the cover, is fitted into a central guide tube in the parasheet container, and houses a spring retainer in which is a compressed spring.


Functioning: As the bomb falls free of the container, the spring in the spring retainer of the parasheet container forces the cover away and releases the safety plunger, thus arming the bomb.  The cover is blown aft and withdraws the parasheet.  When the parasheet is fully withdrawn, the drag on the cover breaks the linen threads, so that the cover falls away.

On impact, the striker moves forward, bending the arms of the brass cross, and fires the detonator.  The flash from the detonator passes through the paper disk covering the hole in the cellophane washer and ignites the primings in the central tube.  The primings ignite the thermite, and this heats the interior of the bomb, thus raising the internal pressure.  The magnesium-alloy striker housing burns away to affording additional venting to the filling in the central tube.  When the pressure has risen to about 300 psi (pounds per square inch), the piston in the automatic valve is raised and the methane and petol solution passes through the flexible tube, into the valve chamber, through the outlet hole in the jet, and through the hole in the bottom of the parasheet container.  As it passes out of the jet, the liquid is ignited by the flame issuing from the vent holes in the striker housing as a result of the burning of the thermite.

Because of the lead weight, the free end of the flexible tube always to the lower side of the bomb as it comes to rest, so that almost all of the liquid charging passes out of the bomb through the jet.  It emits a flame 15 feet high and 2 feet wide.


Suspension: Carried in batches of 14 in Cluster Projectiles, 500lb, No.4 Mk I.
  

Filling: The main filling consists of a solution of methane in 1.3 gallons of petrol.  The bomb is filled under pressure, so that the normal filled pressure inside the bomb is from 90 to 110 psi.

IB 45lb Mk I (Service)
    

Overall length: 18.3 inches
Width: 10 inches by 9.75 inches

Weight empty: 7 pounds
 Weight filled: 45 pounds

Fuzing: No fuze

Tail No: No.36 Mk I

Color and markings: Dull red overall,
stiffeners and distance pieces painted black,
"HANDLE WITH CARE" stencilled between stiffeners.

  

Description: The bomb consists of a square-section, tin-plate, 5-gallon, petrol can.  On one face are two corrugated stiffeners, which serve to increase the strength of the can and also act as distance pieces between the can and the drop bar of the Small Bomb Container in which the bomb is carried.  A charging hole, with screwed cap and washer, and another distance piece are provided at the top of the can.  At diagonally opposite corners on the top of the can are two metal loops for attachment of the 12-inch by 21-in fabric tail, which acts as a flight stabilizer.  Two handles for lifting the bomb are soldered to opposite faces of the can.  Bombs of later issue may have a third handle, located on the face, to which the stiffeners are soldered.


Functioning: The bomb is fuzeless and functions by break-up.  The igniter consists of droplets of a liquid which reacts with water to produce small sparks.  The liquid is dispersed in a thick oil, which floats on water.

The sparks produced are not sufficient to ignite fuel oil or paraffin, but ignite petrol immediately.  Thus, when the KOFQR ignites the petrol, which ignites the layer of oil floating on the water.


Suspension: Three of the bombs are carried in the Small Bomb Container 250lb.


Filling: The charging consists of 4 and 1/2 gallons of aviation or MT petrol mixed with one quart of KOFQR igniter.

Remarks: This bomb is intended for the ignition of patches of fuel oil or petrol present on the surface of the sea, rivers, or other inland waterways, during attacks on oil-carrying vessels or oil-storage installations.

 IB 400lb Mk I (Service)

    

Overall length: 60.8 inches
Body length: 40.7 inches
Body diameter: 17.6 inches
Tail length: 21.2 inches
Tail width: 17.5 inches

Fuzing: Tail Pistol No.60 Mk I

Tail No: No. 79 Mk I

Color and markings: Dull red overall,
black letter stencilling.

  

Body construction: The bomb body consists of a thin sheet-steel cylinder with a tail plate welded at one end and a nose at the other.  The nose is recessed to accommodate a cast-iron weight, which is secured ion position with bolts. 

Three perforated baffles are welded internally to the bomb case to reduce surging of the filling while the bomb is suspended aboard the aircraft.  An internally threaded adapter in the center of the tail plate serves as a charging hole and also for the fitting of the exploder container.  A cowl welded to the tail plate has six equi-spaced springs riveted inside it.  These springs form an attachment for the six fasteners which secure the tail unit to the bomb.  These fasteners consist of a stud and a leaf spring.  The studs have an external screw-driver slot and an internal cam slot.  The cam slot engages the spring attached to the cowl.


Tail Construction: The Tail No.79 Mk I consist of a cylindrical strut attached to the tail cone by means of three tail fins.  The arming fork has only one prong, which engages the T-bar of the Pistol No.60.


Suspension: This bomb is equipped for suspension in either British or American aircraft, having on one side a single suspension lug, and dual lugs 180 degrees removed.


Filling:
Exploders: CE, 3-ring and 2 solid pellets
Filling: 6% Aluminum laurate, 2% creosole, and 5% napalm.

Remarks: This bomb is filled with a highly volatile, inflammable gel which is readily ignited by naked flame, or by contact with water.  The filling may smell of gasoline, or carbolic acid.  Rubber boots, gloves, and eye-shields are recommended for all personnel engaged in disposal operations on this bomb.  If the filling comes into contact with the skin, all traces should be swapped off with a rag soaked in gasoline or paraffin, and the effected area should then be washed with water and the patient treated for alkali burns.  Contaminated equipment should be cleaned with gasoline or paraffin, and then washed with water.

 IB 500lb Mk I (Service)

    

Overall length: 66 inches
Body diameter: 13.1 inches
Body length: 41 inches
Wall thickness: 3/16 inches
Tail length: 28 inches
Tail width: 13.1 inches

Fuzing: Tail Pistol No.30

Tail No: No.31 Mk I

Color and markings: Grey overall,
3-inch red band 7 inches from nose,
3-inch dull red band 9 inches from tail.

  

Body construction: This bomb consists of a cylindrical, metal container with a hemispherical nose and tail piece welded at either end.  Burster containers are located at either end of the bomb, and, in the tail, to one side of the burster tube, is a filling hole closed with a threaded plug.  A tail locating ring is welded around the tail portion of the bomb body.

Although provision is made in the bomb for alternate nose or tail fuzing, the nose pocket is always closed with a plug, and only the tail pocket is employed.


Tail construction: The Tail No.31 Mk I consist of a sheet-metal tail cone to which are riveted four vanes supported by a cylindrical metal strut.  The tail is attached to the bomb by four spring clips which engage the tail locating ring on the after end of the bomb body.  Inside the tail cone, supporting the lower end of the reach rod, is located a diaphragm with four large holes to allow air passage.


Suspension: A single suspension lug is provided for carrying in British planes, and two additional lugs for US suspension are 180 degrees removed.


Filling: 16 gallons of liquid phosphorus

Remarks: This is a special purpose bomb designed primarily for low-level bombing operations.  Its use will be restricted to special missions.

It is recommended that personnel engaged in disposal operations on this bomb be equipped with rubber boots and gloves, and that these be kept damp.  All equipment and protective clothing which may have come into contact with the liquid phosphorus should be washed thoroughly immediately after use.

The contents of this bomb will ignite immediately with a highly incendiary effect upon contact with the air.  Following the bursting of this bomb, a dense smoke screen will be emitted for at least two hours.

 

Smoke Bombs Introduction


There are at present in service use only four smoke bombs, exclusive of thos bombs containing smoke spotting charges.  These are the 4-, 100-, 120-, and 500-lb smoke bombs.  The bombs are used to lay smoke screens to conceal troop movements.

These bombs are fuzed in the tail, except the 120lb, which takes a nose fuze.

Smoke bombs are colored dark green overall with a  red band around the body.  The 4lb bomb is merely a cylindrical sheet-metal can.  The 100lb is the same size and shape as the 45lb incendiary, with a white phosphorus filling.  The 120lb bomb consists of an outer container and an inner smoke canister which is blown out of the rear of the container by an ejection charge.

The 4lb bombs are preferably carried in Cluster Projectile No.6, Mk I, while the 100lb and 120lb smoke bombs are generally carried in the Small Bomb Container, 250lb.  The 500lb bomb is suspended individually in most 500lb bomb stations.

Smoke 4lb Mks I, II, and IV (Service)

    

Overall length: 7.5 inches
Body length: 7.5 inches
Body diameter: 3.6 inches

 Total weight: 8 pounds, 14 ounces
Burning time: Mk I - 4 mins, Mk II - 8-12 mins

Fuzing: Tail Fuze No.859

Tail No: Fabric tail

Color and markings: Dark green overall,
red band around nose.

  

Description: The bomb consists of a cylindrical metal body closed at both ends and containing a smoke composition.  At the tail end of the bomb is a baffle plate secured to the body and provided with a smoke emission hole covered by a strip of primed fabric held in place by two strips of adhesive tape.  Beneath the baffle plate is an igniter pellet secured to a strawboard washer.  The hole in the washer is filled with match composition which contacts the igniter pellet.  The igniter pellet is set in the smoke composition.

Above the baffle plate is a lid secured to the bomb body and provided with a screw-threaded fuze adapter.  The Fuze No.859 Mk I is screwed and cemented into the fuze adapter.


Functioning: When the bomb is released from the Small Bomb Container, the safety cap of the fuze is drawn off by the action of air resistance drogue.  The lead sleeve on the webbing tape attached to the safety pin causes the free end of the tape to clear the waisted portion of the fuze body and be caught in the air stream, thus withdrawing the safety pin.  The fuze is now armed, with the lead ball and striker held away from the detonator by the creep spring alone.

On impact with the target, the fuze functions.  The flash from the detonator passes through the flash hole in the fuze body and fires the primed cambric strip, which in turn ignites the match composition.  The match composition fires the igniter pellet, and this ignites the smoke composition.

The some generated passes through the smoke-emission hole in the baffle plate and builds up pressure beneath the lid, thus bursting the adhesive tape covering the small smoke-emission hole in the lid and permitting the smoke to escape into the air.  After a short period of time the heat evolved in the bomb melts the solder securing the lid to the bomb body, and the pressure of the smoke then forces off the lid.


Suspension: These bombs are designed to be carried either in the 250lb Small Bomb Container, or the 500lb Cluster Projectile No. 6 Mk I, Smoke.  In the former, the bombs are packed 14 in a metal case, and three cases are placed in the Container.  In the latter, 90 bombs are carried in five tiers of 18 bombs each.  They are placed end to end longitudinally, with the fuzes pointing in opposite directions in alternate tiers.


Filling: The filling of the bomb consists of a cambric strip primed with SR 252, a cambric square primed with sulphurless gunpowder, 1/4lb smoke composition SR 269 (M), and 3 and 1/4 lb smoke composition SR 264A (M).

Remarks: Spontaneous ignition of smoke compositions may result if the filling is wetted, especially by sea water.  The bombs are dropped from aircraft to produce a smoke screen to cover land operations.

The Bomb Mk II is identical to the Mk I, except that the smoke composition is slower burning.  The Bomb Mk IV is similar to the Mk II, except that the closing lid of the bomb body and the igniter pellet are slightly altered.

Smoke 100lb Mks I and II (Service)

    

Overall length: 18.3 inches
Body length: 18.3 inches
Body diameter: 10 inches square
Tail length: 21 inches
Tail width: 12 inches
Total weight: 92-95 pounds
Charge/weight ratio: 85% (approx.)

Fuzing: Tail fuze No.854 Mk I

Tail No: Fabric Tail

Color and markings: Dark green overall,
red band around lower part of body.

  

Description: The bomb consists of a thin tin-plate can of square cross-section, to one face of which are soldered two corrugate stiffeners, which serve to increase the strength of the can and also act as distance pieces between the can and the drop bar of the 250lb Small Bomb Container.  A burster container, to take the Fuze No.854 Mk I and its burster, and an offset filling hole are provided in the top of the can, together with a large circular distance piece.

The burster container is closed, during transit and storage, by a rolled-thread tin-plate, transit plug.  The filling hole is permanently sealed by a rolled-thread filling-hole cap, seating on a sealing disc.  This cap must in no circumstances be unscrewed from the bomb; and, as it is fitted with a short Tommy bar, it may be readily distinguished from the transit plug.

Three handles for lifting the bomb are provided, and at two diagonally opposite corners of the can are soldered metal loops for the attachment of a fabric tail, which acts as a stabilizer to the bomb.


Functioning: On impact of the fuzed bomb with its target, the "all-ways" action fuze functions instantaneously.  The explosion of its burster disrupts the bomb and scatters the white phosphorus filling, which, on contact with the air, ignites spontaneously and begins to give off smoke.


Suspension: These bombs are carried three in a 250lb Small Bomb Container.  In the container, they are separated from each other by the distance pieces on the end of each bomb.


Filling: 86lb white phosphorus

Remarks: The Bomb Mk II is similar to the Mk I in operation, differing only in the following minor structural details.  The filling hole is centrally located in the top of the can.  Two small distance pieces are provided at the top of the can and are located at diagonally opposite corners, on either side of the filling hole.  The two metal loops to which the fabric tail is secured differ slightly in design from those used on the Bomb Mk I.

These bombs have a burning time of 15-20 minutes and provide an effective screen 250-300 yards in length.  They are dropped from aircraft to produce smoke screens for covering land operations.

 Smoke 120lb Mks I and II (Service)

    

Overall length: 31 inches
Body length: 15.8 inches
Body diameter: 9.5 inches
Tail length: 15.1 inches
Tail width: 10 inches
Total weight: 120 pounds
Burning time: 20 minutes

Fuzing: Nose Fuze No.864 Mk I

Tail No: No.41 Mk II

Color and markings: Dark green overall,
1/2-inch red band around nose,
tail is light green.

  

Body construction: The bomb consists of a cylindrical body to which the tail unit is secured.  The body houses a metal container filled with a smoke composition, and a gunpowder ejection charge contained in nine celluloid capsules.  The bomb body is a steel tube welded to a flattened nose-piece.  The nose-piece is centrally tapped to receive the fuze, and during transit and storage, is sealed by a nose transit plug and leather washer.  A suspension lug is welded to the exterior of the bomb body.

A steel flash plate, abutting the nose-piece within the bomb body, has a steel collar secured to it.  A small centrally located hole is drilled through the flash plate, and is sealed by a paper disc.  The nine celluloid capsules, each filled with 1 ounce, 1 drm. of gunpowder, are retained in the collar by a cardboard sleeve, and felt and cardboard washers.  The sleeve has six equi-spaced holes near its inner end.

The metal container, filled with approximately 50lb of smoke composition (H.C.E.), is housed in the bomb body against the flash plate.  It has a 3-inch diameter hole sealed with a celluloid disc.  Between this disc and the smoke composition there are four strawboard washers, each with a 1 and 1/2-inch diameter hole, the hole so formed being sealed by two squares of primed fabric.  The container is retained in position against the flash plate by a closing plate fitted into the rear end of the bomb body, and secured by four turned-over metal tabs.

Tail construction: The tail unit is secured to the bomb body by eight drive screws, and consists of a tail cone to which a cylindrical vane is secured by four vane supports.


Functioning: On impact of the bomb with the target, the magazine of the fuze explodes after a delay of not less than 1/2 second, during which period the bomb will have come to rest.  The flash from the fuze magazine, passing through the hole in the flash plate and the celluloid disc, ignites the two primed cambric squares, which in turn ignite the smoke composition in the container.

Concurrently with the ignition of the smoke composition, the flash from the fuze magazine also passes through the holes in the cardboard sleeve to initiate the gunpowder ejection charge contained in the nine celluloid capsules.  The resulting explosion of the gunpowder ejects the tail, the closing plate, the container of burning composition, and the flash plate, clear of the crater formed by the bomb.


Suspension: Two bombs may be carried in a 250lb Small Bomb Container, or the bombs may be suspended individually by a single lug.  The Bombs Mk II may be fitted with twin lugs for suspension in American aircraft.


Filling: Smoke composition (H.C.E.)

Remarks: The smoke composition contained in these bombs is liable to spontaneous ignition if it should become wet, particularly with sea water.  The Bomb Mk II is similar to the Mk I in operation, the principal differences being a modified tail assembly and arrangement for twin suspension lugs for carrying in American aircraft.

Smoke 500lb Mk I (Service)

    

Overall length: 66 inches
Body length: 41 inches
Body diameter: 13.1 inches
Wall thickness: 3/16 inches
Tail length: 28 inches
Tail width: 13.1 inches
Total weight: 400 pounds (approx.)
Charge/weight: 60%

Fuzing: Tail Pistol No.30 Mk IV

Tail No: No.31 Mk I

Color and markings: Dark green overall,
red band around the lower part of the body.

  

Body construction: The bomb consists of a cylindrical metal container with a hemispherical nose and tail piece welded at either end.  Burster containers are located at each end of the bomb and, in the tail, to one side of the burster tube, is a filling hole closed with a threaded plug.  A tail locating ring is welded around the after portion of the bomb body. 

Although provision is made in the bomb for alternate nose or tail fuzing, the nose pocket is always closed with a  plug, and only the tail pocket is employed.


Tail construction: The Tail No.31 Mk I consists of a sheet-metal tail cone to which are riveted four vanes supported by a cylindrical metal strut.  The tail is attached to the bomb by four spring clips, which engage the tail locating ring on the after end of the bomb body.  Inside the tail cone, supporting the lower end of the reach rod, is located a diaphragm with four large holes to allow air passage.


Suspension: A single suspension lug is provided for carrying in British planes, while two additional lugs are located 180 degrees around from the first for American suspension.


Filling: 270 pounds of white phosphorus

Smoke 500lb Mk II (Service)

    

Overall length: 67 inches
Body length: 46 inches
Body diameter: 13 inches
Tail length: 22 inches
Tail width: 13 inches

Fuzing: Tail Fuze No.885 or No.886

Tail No: No.81 Mk I

Color and markings: Dark green overall,
red band near nose,
black stencilling.

  

Body construction: The bomb consists of a cylindrical bomb body made of thin sheet steel, with a nose plate welded to one end of the body.  Three catch brackets, spaced 120 degrees apart, are welded to the nose plate, and a nose fairing is secured to the catch brackets by spring clips.  Immediately beneath the nose plate is located a loading plate.  An exploder pocket is welded to the nose plate and contains an ejection charge.  A nose plug is screwed into the exploder pocket.

An igniter tube with four series of perforations extends down the center axis of the bomb and contains a celluloid tube holding a primed cambric tube.  The igniter tube is held in place by the igniter-tube holder, located in the center of the tail plate.  The remainder of the bomb body is filled with three banks of smoke generators, each bank consisting of eight wedge-shaped units fitted with drag plates.

A tail plate, to which is welded the fuze adapter, is secured to the inside of the after end of the bomb body by six brass rivets.  A tail locating ring is fitted to the inside of the tail plate.

Tail construction: The Tail No.81 Mk I consists of a cylindrical strut held in place on the truncated tail cone by four sheet metal fins.  The tail is held in place on the bomb by the usual four spring clips, which engage in four similar recesses in the tail ring on the bomb body.  A locating pin in the tail ring engages a slot in the bottom edge of the tail cone to position the tail.


Functioning: When the bomb is released from the aircraft, the fuze is armed.  At a predetermined height, the fuze functions and the flash from the fuze magazine ignites the contents of the igniter tube.  The perforations in the igniter tube allow the burning celluloid and primed cambric to initiate the smoke generators and eventually the ejection charge.  The pressure of the gases generated by the ignition of the ejection charge bears against the loading plate and forces the whole inner assembly against the tail plate, which shears the six brass rivets holding it to the bomb casing.  The tail plate and attached tail unit are then thrown clear of the bomb, and the bomb contents are ejected through the tail.


Suspension: This bomb is equipped for suspension in either British or American aircraft, having a single suspension lug on one side and dual lugs 180 degrees removed.


Remark: Should water, especially sea water, come into contact with the smoke composition used in this bomb, the smoke composition is liable to spontaneous combustion due to chemical action.

Light Chase (Chemical) Bombs Introduction


There are at present in service use only four sizes of L.C. (chemical) bombs.  These are the 30-, 65-, 250-, and 500-lb LC bombs.  These bombs are designed to contaminate an area by dispersal of their gas filling.

The 30- and 65-lb bombs are constructed of very light gauge metal, and are designed to operate either by break-up on impact, or by functioning of their fuzes.  The 250- and 500-lb bombs are made of slightly heavier gauge metal, and are nose fuzed to function on impact with a target, or possibly for aerial burst, in the case of the 500-lb bomb.

All L.C. bombs are painted grey overall and have additional color bands to indicate the type of gas with which they are filled.

LC 30lb Mks I and IM (Service)

    

Overall length (fuzed): 32.75 inches
Body diameter: 5 inches

Total weight: 30 pounds (approx.)

Fuzing: Nose Fuze No.38 Mk I or II

Color and markings: Grey overall,
colored bands to indicate filling.

  

Body construction: The bomb consist of a steel, tubular body to which is welded a steel tail plate, a steel nose plate, and a nose fairing.  The fuze container is screwed and welded into the nose plate.

A spigot, having a central charging hole, is welded into the tail plate and closed by the charging-hole plug.  The spigot has external threads onto which the trail is threaded.

The inside of the bomb usually has a protecting coating of bakelite varnish to retard corrosion.  The external areas around the charging hole plug and fuze container are painted with khaki detector paint, which turns red when exposed to gas.

Tail construction: The tail consists of a tin-plate cone, the apex of which is surrounded by a cylindrical tail vane connected to the cone by vane supports.  A diaphragm, having a threaded hole by which the tail is threaded onto the spigot, closes the base of the tail; and a tail adapter closes the apex of the tail.  An adjusting bolt, having a rounded head, is screwed into the tail adapter and locked in position by a lock nut.


Functioning: On impact with a soft target the fuze functions, and, after a short delay during which time the bomb has come to rest, ignites the gunpowder ejection charge, thus blowing off the tail and tail plate and ejecting the chemical filling.  On impact with a hard target, the bomb will normally break up and distribute the charging before the ejection charge functions.


Suspension: The Mk I and Mk IM can be carried in the 250lb Small Bomb Container.  The Mk IM can be used on a Light Series bomb carrier when fitted with a suspension band.


Remarks: The Bomb Mk I may be fitted with retarding equipment consisting of a flat nose cap, which replaces the nose fairing, and a flat steel retarded plate, which is held in place on the tail by the adjusting bolt and lock nut.

The Mk IM bomb is the same as the Mk I except for two locating pieces, welded to the body, which serve to locate a suspension band. 

  

LC 30lb Mk II (Service)

    

Overall length: 32.8 inches
Body diameter: 5 inches

Total weight: 30 pounds (approx.)

Fuzing: None

Color and markings: Grey overall,
colored bands to indicate filling.

  

Body construction: The bomb has a cylindrical, plated body of light-gauge metal.  A steel nose is threaded onto a nose spigot and held in position by a securing screw.  A compression chamber in the nose of the bomb collapses if the bomb is roughly handled, and so reduces the possibility of rupturing the seams of the bomb.

The tail is screwed onto a tail spigot which contains the charging hole and is closed by the charging hole plug.  Adhesive tape provides an external seal between the tail and the bomb body.  The after end of the tail is closed by a closing cap.

The inside of the bomb usually has a protective coating of bakelite varnish, and the areas around the charging-hole plug and body seams, also the adhesive tape, are painted with khaki detector paint, which turns red when exposed to gas.


Functioning: The bomb breaks upon impact with a target and scatters the filling.  It should not be dropped on soft targets from over 1,000 feet.


Suspension: The bomb is carried in a 250lb Small Bomb Container.

LC 65lb Mks I and II (Service)

    

Overall length: 18.3 inches
Body diameter: 6 inches (approx.)

Total weight: 63 pounds (approx.)

Fuzing: None

Color and markings: Grey overall,
colored bands to indicate filling.

  

Body construction: The bodies of the Bombs Mk I and Mk II are the same as those of the Smoke 100lb Mks I and II, respectively, except that the LC bombs do not have any provision for fuzing.  The tails of both LC and Smoke bombs are exactly the same.


Functioning: On release from the Small Bomb Container, the fabric tail of each bomb unfurls and acts to stabilize the bomb in flight.  On impact with the target, the bomb breaks up and the filling is scattered.


Suspension: Three bombs are carried in the 250lb Small Bomb Container. 

LC 250lb Mks I, IB.V., II, and II* (Service)

    

Body length: 34.25 inches
Body diameter: 12 inches
Tail length: 27.2 inches
Tail width: 12 inches

Total weight: 250 pounds (approx.)

Fuzing: Nose Fuze No.36 Mks I and II when loaded in Universal-type bomb carrier; Nose Pistol No.44 when tier-type stowage is used.

Tail No: No.1 Mk I

Color and markings: Grey overall,
colored bands to indicate filling.

  

Body construction: The Bomb Mk II consist of a tubular steel body to which a hemispherical nose is welded.  A burster container is screwed and cemented into the nose.  A tail plate is welded to the other end of the body and has a spigot through which passes a charging hole.  The charging hole is closed by a square-headed charging hole plug.  The skirt of the tail plate is provided with two bayonet slots and a circular hole to retain the tail or transit base.  The interior of the bomb is varnished, and the areas around the charging-hole plug and the burster container are coated with khaki-colored detector paint, which turns red when exposed to gas.


Tail construction: The Tail No.1 Mk  I consists of a tail cone at the apex of which a circular strut is attached by fins.  A skirt at the base of the tail cone has two fixed pins and a third pin, secured to a leaf spring, which engage the bayonet slots and the hole in the skirt of the tail.


Suspension: The bomb is fitted with a single suspension lug for carrying on a Universal-type bomb carrier.  It is also carried in US aircraft using tier-type bomb stowage.  The bomb may also be equipped with a trunnion band for carrying on dive bombers.


Filling: Chemical warfare agent.

Remarks: The Bomb Mk II* is the same as the Mk II, only the burster container is welded in addition to being screwed and cemented in place.  The bomb Mk I differs from the Mk II in that the interior is unvarnished and the burster container is secured by welding only.  The Mk IB.V. differs from the Mk II in that the burster container is welded on, and the tail plate has a slightly smaller internal diameter.  The letters B.V. stand for the "Bakelite Varnish" which is applied internally to the walls of this bomb.

LC 500lb Mk II (Service)

    

Overall length: 66 inches
Body length: 41 inches
Body diameter: 13.1 inches
Tail length: 28 inches
Tail width: 12.8 inches
Total weight: 330lb (approx.)

Fuzing:
-Aerial Burst: US Nose Fuze M111, M111 A1, or M111 A2;
-Ground Burst: Nose Pistol No.44 Mk I, II, or III, and Tail Pistol No.30 Mk IV.

Tail No: No.31 Mk I

Color and markings: Grey overall,
colored bands to indicate filling.

  

Body construction: The bomb consists of a light, tubular container of welded sheet steel to which a nose dome and tail dome, each fitted with a burster container, are welded.  The tail dome also contains the charging hole, which is closed by a steel charging hole plug.  A tail locating ring is welded to the tail dome.

The body has four rectangular slots and a locating pin for the attachment of the tail.  The interior of the bomb is unvarnished.


Tail construction: The Tail No.31 Mk I consists of a tail cone to which a cylindrical strut is attached by four tail fins.  The base of the cone is fitted with four spring clips, each of which is provided with a turnbuckle locking clip.  A slot on the base of the cone fits over the locating pin on the bomb to insure correct positioning on assembly.

The conventional type of arming assembly is fitted into the tail.


Suspension: A single suspension lug is present for use on British planes, while two lugs 180 degrees removed, provide for suspension on US planes.


Filling: 14 and 1/2 gallons of the designated chemical warfare agent.

Next Time: Practice, Infantry Training, and Miscellaneous Bombs