British Explosive Ordnance
Obsolete Bombs Introduction
The various bombs of different types included in this section have all been declared obsolete, but because of the possibility that they still may be encountered, it is deemed desirable to give complete information regarding them.
Older obsolete bombs, included only as a matter of interest, are listed in chart form at the end of the chapter.
AT 9lb, Mk I (Obsolete)
Overall length: 14 inches
Maximum body diameter: 4 and 1/2 inches squared
Maximum body diameter: 4 and 1/2 inches squared
Total weight: 8.5 pounds
Charge/weight ratio: 80%
Fuzing: Tail Fuze No.847
Charge/weight ratio: 80%
Fuzing: Tail Fuze No.847
Color and markings: Dark green overall,
1/2-inch red band around nose.
1/2-inch red band around nose.
Body Construction: The body is made of thin metal, approximately rectangular in shape, having a square cross section with rounded corners. It tapers slightly from the rear toward the nose. The body is closed at the nose end by a front cover housing a nose cup, which is taped and cemented in place. The nose cup of the rear bomb forms a safety device for the fuze in the front bomb of a pair, as bombs are dropped in pairs. The rear cover is located approximately in the middle of the bomb. The bomb incorporates a steel, cone-shaped charge.
Tail Construction: The tail is integral with the body, being only a continuation of the thin metal case. The rear bomb of a pair has a retarder plate to pull the rear bomb free of the front one when dropped from the container. The tail also has a safety tube of light-gauge metal with a cardboard inner sleeve, forming a safety device for the fuze of the rear bomb of a pair. A locating plate near the rear of the safety tube locates the tube in the tail of the bomb.
Suspension: These bombs are carried in the 250lb Small Bomb Container, which holds 24 bombs. They are loaded in pairs, with the nose of the rear bomb houses in the tail of the front bomb.
Filling:
-Exploder: CE pellet housed in the bottom of the exploder container
-Filling: Nobel's explosive No.808, with shaped charge effect.
Remarks: The bomb is designed for use against tanks and armored vehicles. It will blow a hole approximately nine inches in diameter in armor plating 2 inches thick, and is effecting at striking angles up to 45 degrees.
The 9lb AT Practice Bomb Mk I is approximately the same shape, size, and filled weight, and has the same approximate ballistic characteristics. However, it has neither exploder nor detonator. Its body breaks up on impact with the target to release a white filling, clearly visible from the air.
Tail Construction: The tail is integral with the body, being only a continuation of the thin metal case. The rear bomb of a pair has a retarder plate to pull the rear bomb free of the front one when dropped from the container. The tail also has a safety tube of light-gauge metal with a cardboard inner sleeve, forming a safety device for the fuze of the rear bomb of a pair. A locating plate near the rear of the safety tube locates the tube in the tail of the bomb.
Suspension: These bombs are carried in the 250lb Small Bomb Container, which holds 24 bombs. They are loaded in pairs, with the nose of the rear bomb houses in the tail of the front bomb.
Filling:
-Exploder: CE pellet housed in the bottom of the exploder container
-Filling: Nobel's explosive No.808, with shaped charge effect.
Remarks: The bomb is designed for use against tanks and armored vehicles. It will blow a hole approximately nine inches in diameter in armor plating 2 inches thick, and is effecting at striking angles up to 45 degrees.
The 9lb AT Practice Bomb Mk I is approximately the same shape, size, and filled weight, and has the same approximate ballistic characteristics. However, it has neither exploder nor detonator. Its body breaks up on impact with the target to release a white filling, clearly visible from the air.
HE 20lb Mk I (Obsolete)
Overall length: 25 inches
Body length (w/o tail adapter): 11 inches (approx.)
Body diameter: 5.175 inches
Tail length (w/ tail adapter): 12 inches (approx.)
Tail width: 6 inches (approx.)
Body length (w/o tail adapter): 11 inches (approx.)
Body diameter: 5.175 inches
Tail length (w/ tail adapter): 12 inches (approx.)
Tail width: 6 inches (approx.)
Total weight: 27 pounds (approx.)
Charge/weight ratio: 20% (approx.)
Fuzing: Nose Pistol No.16
Charge/weight ratio: 20% (approx.)
Fuzing: Nose Pistol No.16
Color and markings: Dark green overall,
1/2-inch red band and 1 inch light green band around nose.
1/2-inch red band and 1 inch light green band around nose.
Body Construction: The bomb has a steel, semi-steel or malleable-iron body, hollow and open at both ends, with the forward end threaded internally to receive the nose adapter, and the after end internally threaded to take the tail adapter. The nose adapter has three different-sized threads, to take the detonator-holder and the exploder container from the rear,a nd the pistol from the front. The flange of the nose adapter is externally threaded to receive a screw-on pistol cover. The tail adapter is tapered to conform to the rearward streamlining of the body, with a central bore threaded to receive the tail rod.
Tail Construction: The bomb has a wooden tail cone, conforming to the streamlined shape of the body. Two diametrical saw-cuts at right angles extend from the after end, over a slightly greater length than that of the tail vanes, to accommodate the four sheet-metal tail vanes, which are made in integral pairs. The tail cone is bored axially to take the tail rod, and fits into the cavity in the tail adapter.
Suspension: A wrought-iron or mild steel suspension lug is riveted to the bomb body.
Filling:
-Exploder: 3 sold and 1 perforate CE pellets.
-Filling: 5 pounds (approx.) TNT
Remarks: This bomb was intended for attacking personnel, air strips, and road transports.
Tail Construction: The bomb has a wooden tail cone, conforming to the streamlined shape of the body. Two diametrical saw-cuts at right angles extend from the after end, over a slightly greater length than that of the tail vanes, to accommodate the four sheet-metal tail vanes, which are made in integral pairs. The tail cone is bored axially to take the tail rod, and fits into the cavity in the tail adapter.
Suspension: A wrought-iron or mild steel suspension lug is riveted to the bomb body.
Filling:
-Exploder: 3 sold and 1 perforate CE pellets.
-Filling: 5 pounds (approx.) TNT
Remarks: This bomb was intended for attacking personnel, air strips, and road transports.
RL 112lb Mks V, VI, and VIII (Obsolete)
Overall length: 18 inches
Body diameter: 8 inches
Wall thickness: Solid body
Body diameter: 8 inches
Wall thickness: Solid body
Total weight: 10 pounds
Fuzing: Nose Pistol No. 8 Mk I, or Nose Pistol No.19 Mks I and II; Tail Pistol No.5B Mks I and II
Fuzing: Nose Pistol No. 8 Mk I, or Nose Pistol No.19 Mks I and II; Tail Pistol No.5B Mks I and II
Color and markings: Yellow overall,
1/2 inch red band around nose,
1 inch light green band around body.
1/2 inch red band around nose,
1 inch light green band around body.
Body Construction: The body of these bombs is a single streamlined casting, steel for Mks V and VII and iron for Mk VI, threaded at the nose and tail to take adapters for the central exploder tube.
Tail Construction:
Mk V: The tail of the Bomb Mk V consists of four tail fins, which fit over the body and are fastened in place with screws. Two sets of box-type struts reinforce the tail fins.
Mks VI and VII: The tail assembly of the Bombs Mk VI and Mk VII consists of a tail cone, which slides over the after end of the bomb body and sis secured by a locknut on the exploder tube. Four tail fins are riveted on the cone and are held in place by two sets of box-type struts.
Suspension: The Bomb Mk V has a U-shaped eye-bolt secured to the body with screws at the center of gravity.
The Bombs Mk VI and Mk VII have a U-shaped eye-bolt fastened to a suspension band around the center of gravity.
Filling:
-Exploder: TNT and CE pellets
-Filling: Amatol 80/20, or TNT
Tail Construction:
Mk V: The tail of the Bomb Mk V consists of four tail fins, which fit over the body and are fastened in place with screws. Two sets of box-type struts reinforce the tail fins.
Mks VI and VII: The tail assembly of the Bombs Mk VI and Mk VII consists of a tail cone, which slides over the after end of the bomb body and sis secured by a locknut on the exploder tube. Four tail fins are riveted on the cone and are held in place by two sets of box-type struts.
Suspension: The Bomb Mk V has a U-shaped eye-bolt secured to the body with screws at the center of gravity.
The Bombs Mk VI and Mk VII have a U-shaped eye-bolt fastened to a suspension band around the center of gravity.
Filling:
-Exploder: TNT and CE pellets
-Filling: Amatol 80/20, or TNT
GP 120lb Mks I and II (Obsolete)
Overall length: 42.4 inches
Body length: 21.5 inches
Body diameter: 8.1 inches
Wall thickness: 0.5 inches
Tail length: 15.7 inches
Tail width: 8 inches
Body length: 21.5 inches
Body diameter: 8.1 inches
Wall thickness: 0.5 inches
Tail length: 15.7 inches
Tail width: 8 inches
Total weight: 120 pounds (Amatol 80/20)
Charge/weight ratio: 25%
Fuzing: Nose Pistol No.19; Tail Pistol No.21
Charge/weight ratio: 25%
Fuzing: Nose Pistol No.19; Tail Pistol No.21
Color and markings: Yellow overall,
1/2-inch red band around nose and 1 inch light green band around body,
longitudinal green bar on body and tail indicates explodering scheme..
1/2-inch red band around nose and 1 inch light green band around body,
longitudinal green bar on body and tail indicates explodering scheme..
Body Construction: The body is a streamlined steel casting or forging, threaded at the nose to take the nose adapter, which holds the central exploder tube. At the other end of the casting is a threaded base plug through which the exploder tube passes. Welded to the end of the casting is a streamlined section of thin metal, containing no explosive, which is tapered to take the tail ring. The exploder passes through this section also.
Tail Construction: A truncated cone fits over the rear section of body and is held to it by a locknut over the exploder tube. Three mild-steel fins are fastened to the cone, and are reinforced by a cylindrical strut.
Suspension: The bomb uses a single suspension lug secured to the body by four screws.
Filling:
-Exploder: TNT and CE pellets
-Filling: 36.5 pounds TNT, or 30 pounds Amatol 80/20
Tail Construction: A truncated cone fits over the rear section of body and is held to it by a locknut over the exploder tube. Three mild-steel fins are fastened to the cone, and are reinforced by a cylindrical strut.
Suspension: The bomb uses a single suspension lug secured to the body by four screws.
Filling:
-Exploder: TNT and CE pellets
-Filling: 36.5 pounds TNT, or 30 pounds Amatol 80/20
GP 500lb Mks I, II and III (Obsolete)
Overall length: 68.7 inches
Body length: 35.7 inches
Body diameter: 13 inches
Wall thickness: 7/8 inches
Tail width: 13 inches
Body length: 35.7 inches
Body diameter: 13 inches
Wall thickness: 7/8 inches
Tail width: 13 inches
Total weight: 509 pounds (TNT)
Charge/weight ratio: 28%
Fuzing: Nose Pistol No.19; Tail Pistol No.17 or 22
Tail No.: No.1 Mk I (Mk III bomb only)
Charge/weight ratio: 28%
Fuzing: Nose Pistol No.19; Tail Pistol No.17 or 22
Tail No.: No.1 Mk I (Mk III bomb only)
Color and markings: Yellow overall,
1/2-inch red band around nose and 1 inch light green band around body,
light green bar on body and tail indicates explodering scheme..
1/2-inch red band around nose and 1 inch light green band around body,
light green bar on body and tail indicates explodering scheme..
Body Construction: The body is a streamlined steel casting or forging threaded at the nose to take the nose adapter, which holds the central exploder tube. At the opposite end is a threaded base plug through which the exploder tube passes. Welded to the after end of the body is a streamlined cone of thin metal, containing no explosive, which is tapered to take the tail ring. The exploder also passes through this section.
Tail Construction: The tail has a truncated cone, which fits over the rear section of the body and is held to it by a locknut over the exploder tube. Four mild-steel fins are fastened to the cone, and are reinforced by a cylindrical strut.
Suspension: The bomb is suspended by a single suspension lug secured to the body by four screws.
Filling:
-Exploder: TNT and CE pellets
-Filling: 143 pounds TNT, or 134 pounds Amatol 80/20
Tail Construction: The tail has a truncated cone, which fits over the rear section of the body and is held to it by a locknut over the exploder tube. Four mild-steel fins are fastened to the cone, and are reinforced by a cylindrical strut.
Suspension: The bomb is suspended by a single suspension lug secured to the body by four screws.
Filling:
-Exploder: TNT and CE pellets
-Filling: 143 pounds TNT, or 134 pounds Amatol 80/20
Remarks: The tail fins are usually painted red when time pistols are used.
HC 2000lb Mk I (Obsolete)
Overall length: 162 inches
Overall length: 162 inches
Body length: 99.5 inches
Body diameter: 18.5 inches
Wall thickness: 0.19 inches
Tail length: 60 inches
Tail width: 18.6 inches
Wall thickness: 0.19 inches
Tail length: 60 inches
Tail width: 18.6 inches
Total weight: 1842 pounds
Charge/Weight ratio: 73%
Fuzing: Nose Pistol No.27, 42, or 44
Tail No.: No.32 Mk I, or No.10 Mk I or II, or Parachute Attachment
Charge/Weight ratio: 73%
Fuzing: Nose Pistol No.27, 42, or 44
Tail No.: No.32 Mk I, or No.10 Mk I or II, or Parachute Attachment
Color and markings: Dark green overall,
1/2-inch red band 3 and 1/2 inches from front edge of cylindrical shell,
2-inch light green band 16 inches from edge.
1/2-inch red band 3 and 1/2 inches from front edge of cylindrical shell,
2-inch light green band 16 inches from edge.
Body Construction: The body consists of a cylindrical steel shell with a hollow, conical nose piece welded to one end, parallel sides, and a closing plate bolted to an angle ring which is welded in position a short distance within the other end. A radial strengthening band is welded internally at the center of gravity, and its ends are welded to a steel block. Holes tapped through the shell and steel block receive the suspension lug screws. Side pockets for supplementary fuzing are present near the base end, but are not used. The shell is strengthened longitudinally by two channel beams welded to each end of a central steel block and to the shell interior.
Tail Construction: The Tail No.32 Mk I assembly consists of a cylinder of light-gauge metal with a metal tray secured in its forward end and a strengthening ring in its open rear end. The tray has a series of equispaced bayonet dogs for attaching to the body bayonet joints welded to it. The cylinder has a number of openings to give it stability.
The parachute attachment has a parachute 5 feet, 6 inches in diameter, attached to a metal tray having bayonet dogs for attaching it to the body. The parachute is retained by waterproofed fabric and a retaining pin. The retaining pin is attached to a static cord stitched on the outside of the last protective panel, and connected to the bomb carrier or aircraft. On release the cord pulls the retaining pin and chute free, and breaks off from the plane when the chute is extended.
Suspension: The bomb is suspended by a single suspension lug bolted to the body and an internal steel block at the center of gravity. The screw holes are closed by transit screws until the bomb is to be used, at which time the lug is attached.
Explosive Components:
Exploders: A central exploder tube extends from the nose exploder container. The tube contains eight 33 and 1/4 ounce TNT exploders. The exploder container contains a 9 ounce TNT exploder.
Filling: 1340lb Amatol 60/40 sealed at each end with an approved composition
Remarks: This bomb may be fitted with a nose attachment of light-gauge metal to retard the bomb in flight. It consists of a cylinder fitting over the forward end of the body shell and projecting forward beyond it around the conical nose piece. Two side fuzing pockets are usually not used, but might contain the Time Pistol No.47.
Tail Construction: The Tail No.32 Mk I assembly consists of a cylinder of light-gauge metal with a metal tray secured in its forward end and a strengthening ring in its open rear end. The tray has a series of equispaced bayonet dogs for attaching to the body bayonet joints welded to it. The cylinder has a number of openings to give it stability.
The parachute attachment has a parachute 5 feet, 6 inches in diameter, attached to a metal tray having bayonet dogs for attaching it to the body. The parachute is retained by waterproofed fabric and a retaining pin. The retaining pin is attached to a static cord stitched on the outside of the last protective panel, and connected to the bomb carrier or aircraft. On release the cord pulls the retaining pin and chute free, and breaks off from the plane when the chute is extended.
Suspension: The bomb is suspended by a single suspension lug bolted to the body and an internal steel block at the center of gravity. The screw holes are closed by transit screws until the bomb is to be used, at which time the lug is attached.
Explosive Components:
Exploders: A central exploder tube extends from the nose exploder container. The tube contains eight 33 and 1/4 ounce TNT exploders. The exploder container contains a 9 ounce TNT exploder.
Filling: 1340lb Amatol 60/40 sealed at each end with an approved composition
Remarks: This bomb may be fitted with a nose attachment of light-gauge metal to retard the bomb in flight. It consists of a cylinder fitting over the forward end of the body shell and projecting forward beyond it around the conical nose piece. Two side fuzing pockets are usually not used, but might contain the Time Pistol No.47.
AS 35lb Mks I and II (Obsolete)
Overall length: 29.2 inches
Fuzing: Nose Fuze No.866
IB 250lb Mks I and II (Obsolete)
Overall length (w/o fuze): 61 inches (approx.)
Body length: 34.1 inches
Remarks: This bomb was intended primarily for attacking forested areas, and can be dropped from heights up to 8,000 feet.
Overall length: 29.2 inches
Body length: 17.2 inches
Body diameter: 7 inches
Wall thickness: 0.064 inches
Tail length: 17 inches (approx.)
Tail width: 7 inches
Wall thickness: 0.064 inches
Tail length: 17 inches (approx.)
Tail width: 7 inches
Total weight: 35 pounds
Charge/Weight ratio: 46%
Charge/Weight ratio: 46%
Fuzing: Nose Fuze No.866
Color and markings: Dark green overall,
1/2-inch red band and 1-inch light green band around body.
1/2-inch red band and 1-inch light green band around body.
Body Construction: The bomb has parallel sides, with a nose adapter and a tapered rear section. A tail adapter secures the tail to the body. The explosive charge is cone shaped, employing the principle of Munroe shaped charge. A cylindrical nose attachment is welded onto the nose adapter by four tack welds. The exploder is in the rear of the body, and is initiated by a flash from the nose fuze, communicated through the supporting tube extending from the nose cavity to the exploder.
Tail Construction: The tail consists of a long hollow tube with a cylindrical strut attached to it by six fins. The tail threads into the tail adapter, and is secured by a locking screw. The six fins are formed by three sets of W-shaped supports welded to the tail tube.
Suspension: The Bomb Mk I has a single lug for suspension in aircraft. The Mk II has no lug, as it is intended to be fired from shipboard.
Explosive Components:
Exploder: CE pellets
Filling: 16lb RDX/TNT 60/40. The after end is sealed by a 1/4-inch topping of TNT.
Remarks: The Bomb Mk I was designed for use by Coastal Command and was intended to be dropped from aircraft. The Bomb Mk II has no suspension lug, and is intended for spigot projection from ships.
DC 450lb Mk VII (Obsolete)
Overall length: 67.25 inches
Body length: 27.75 inches
IB 25lb Mks I and II (Obsolete)
Overall length: 32.6 inches
Body diameter: 5.03 inches
Tail Construction: The tail consists of a long hollow tube with a cylindrical strut attached to it by six fins. The tail threads into the tail adapter, and is secured by a locking screw. The six fins are formed by three sets of W-shaped supports welded to the tail tube.
Suspension: The Bomb Mk I has a single lug for suspension in aircraft. The Mk II has no lug, as it is intended to be fired from shipboard.
Explosive Components:
Exploder: CE pellets
Filling: 16lb RDX/TNT 60/40. The after end is sealed by a 1/4-inch topping of TNT.
Remarks: The Bomb Mk I was designed for use by Coastal Command and was intended to be dropped from aircraft. The Bomb Mk II has no suspension lug, and is intended for spigot projection from ships.
DC 450lb Mk VII (Obsolete)
Overall length: 67.25 inches
Body length: 27.75 inches
Body diameter: 17.5 inches
Tail length: 32 inches (approx.)
Tail width: 17.5 inches
Tail length: 32 inches (approx.)
Tail width: 17.5 inches
Total weight: 450 pounds
Charge/weight ratio: 64%
Fuzing: Mk X** pistol and depth adjuster
Charge/weight ratio: 64%
Fuzing: Mk X** pistol and depth adjuster
Color and markings: Dark green overall with circumferential red and green bands
Body Construction: The body consists of a welded cylindrical case, closed by two covers connected by a central tube called the primer tube. This tube, housing the primer, pistol, and depth adjuster, has an internal diameter of 3.5 inches. Three lifting eyes with rings are provided, one on the cover at the primer end, and two on the cover at the opposite end. The cover at the primer end has two filling holes which are closed by bungs. It may or may not have a nose attachment and tail. The bomb is carried on aircraft with the primer end forward, except when fitted with the parachute attachment, in which case the pistol and depth adjuster are forward.
Nose Attachment: The bomb may use a hemispherical hollow nose held on by the side straps, which also secure the tail assembly.
Tail Construction: The tail, when fitted, consists of a cylindrical strut attached to a hollow tail cone by four fins. Three brackets, equispaced around the cone, are fitted to take the ends of the straps which secure the nose and tail attachments, both of which break off on impact with water. The bomb may have a parachute attachment on the primer end if dropped from high-speed aircraft.
Suspension: The bomb is suspended by a single lug on a suspension band around the center of gravity.
Explosive Components:
Filling: 290lb Amatol
Nose Attachment: The bomb may use a hemispherical hollow nose held on by the side straps, which also secure the tail assembly.
Tail Construction: The tail, when fitted, consists of a cylindrical strut attached to a hollow tail cone by four fins. Three brackets, equispaced around the cone, are fitted to take the ends of the straps which secure the nose and tail attachments, both of which break off on impact with water. The bomb may have a parachute attachment on the primer end if dropped from high-speed aircraft.
Suspension: The bomb is suspended by a single lug on a suspension band around the center of gravity.
Explosive Components:
Filling: 290lb Amatol
IB 25lb Mks I and II (Obsolete)
Overall length: 32.6 inches
Body diameter: 5.03 inches
Tail length: 13.55 inches
Total weight: 25 pounds
Fuzing: Simple impact striker
Fuzing: Simple impact striker
Color and markings: Dull red overall,
two 1/2-inch black bands separated by 1/2-inch red band painted around the nose.
two 1/2-inch black bands separated by 1/2-inch red band painted around the nose.
Description: The Bomb Mk I consists of a cylindrical steel tube secured to a hollow, sharp-pointed nose by a nose adapter (built up externally to streamlined form by a cardboard fairing), a column of seven closed containers, termed fire-pots, accommodated in the body tube, a flanged base adapter which affords a mounting for a cap holder, a tail cone with a cylindrical tail vane secured to it by four vane supports, and a tail tube which accommodates a striker pellet, with a shear wire and creep spring, and a safety rod.
Each of the seven fire-pots consists of a cylindrical container made of magnesium alloy and formed with a central tube, which communicates, through a fire hole, with a recess in a central boss on the base of the container. The container is closed by a magnesium alloy lid, which has a shallow central recess in its outer side. Holes through he lid place this recess in communication with the interior of the container. The ignition cap contains a layer of gunpowder and a layer of detonating composition.
The central tube of each of the fire-pots houses a delay charge and is surrounded by a delay charge and a priming charge for the thermite and magnesium filling, which occupies the remainder of the annular chamber in the fire-pot. A loop of quickmatch extends into the bore of the central tube and has its two ends carried out through the slots in the tube and through two of the holes in the lid. An ejection charge of gunpowder is retained in the recess in a central boss of each fire-pot by a paper disc, which is secured in position by shellac.
The tail cone fits over the flange of the base adapter and is held assembled to the bomb body by a tail nut, which screws onto the rear end of the tail tube against a tail adapter. The tail adapter fits into the rear end of the tail cone.
The striker pellet has a sharp point at the forward end and is held in the safe position by a shear wire passed through holes in the striker pellet and tail tube. The ends of the shear wire are soldered to prevent removal. The rear end of the striker pellet receives the forward threaded end of the safety rod. The creep spring is house in the forward end of the tail tube and bears against the cap holder and the striker pellet. The safety rod passes through the tail tube and is screwed into the threaded bore of the striker pellet.
The Bomb Mk II has only a slight difference in the tail plate.
Parachute Attachment: Either a Parachute Attachment No.1 Mk I or a No.1 Mk II may be used with this bomb. The Attachment No.1 Mk I consists of a small parachute housed in a container of sheet metal, consisting of a cylindrical housing plate and a cover. It fits loosely in the cylindrical strut of the bomb tail. The chute is 15 inches in diameter and vented at the peak. The Attachment No.1 Mk II is similar, except that it is housed in a collapsible cardboard container between cardboard packing discs.
Striker Attachment: There are two striker attachments, the No.1 Mk I, and the No.1 Mk II. No.1 Mk I consists of a coupling fork, snatch rod, striker rod, coupling socket, and a retaining sleeve, which houses a spring. The No.1 Mk II is similar, except that the coupling fork is fitted with a quick-release pin.
Functioning: Whent he bomb using the Parachute and Striker Attachments No.1 Mk I is released, the cover pulls the chute out. The chute opens and pulls the snatch rod against the action of the spring until the striker rod retaining balls escape into the annular recess in the retaining sleeve. The striker rod then moves down against the striker pellet. On impact, the inertia of the rod and pellet combine to shear the shear wire, overcome the creep spring, and pierce the ignition cap, igniting the blowing charge and blowing the base adapter and complete tail and parachute assembly from the body tube. The quickmatch, which passes through the lid and into the central tube of the rearmost magnesium alloy fire-pot, is also ignited, and, in turn, the quickmatch ignites the delay charges in and around the central tube of the fire-pot.
While the central tube delay charge is burning through, the outer delay charge initiates the surrounding priming charge, which, in turn, ignites the incendiary composition around it. Meanwhile, the central delay charge burns through and fires the ejection charge in the base of the fire-pot. This has the effect of ejecting the activated fire-pot from the bomb and also igniting the quickmatch of the second fire-pot, etc. Each ejected fire-pot will continue to burn for approximately 10 minutes; the magnesium alloy container and lid being consumed.
Finally, the quickmatch in the lod closing the nose of the bomb is ignited by the last ejection charge and initiates the priming charge, which, in turn, ignites the incendiary composition of the nose, and provides an additional fire source.
When used with the Parachute and Striker Attachment No.1 Mk II, the parachute is blown out of the cylindrical shroud on the tail and the chute opens, freeing the striker mechanism. Functioning after this is the same as that with Attachments No.1 Mk I.
Suspension: The bombs may be carried in a Small Bomb Container, or from a bomb carrier by a lug on a suspension band.
Explosive Components:
Filling: 1lb Thermite, and 5lb, 4oz Magnesium
Each of the seven fire-pots consists of a cylindrical container made of magnesium alloy and formed with a central tube, which communicates, through a fire hole, with a recess in a central boss on the base of the container. The container is closed by a magnesium alloy lid, which has a shallow central recess in its outer side. Holes through he lid place this recess in communication with the interior of the container. The ignition cap contains a layer of gunpowder and a layer of detonating composition.
The central tube of each of the fire-pots houses a delay charge and is surrounded by a delay charge and a priming charge for the thermite and magnesium filling, which occupies the remainder of the annular chamber in the fire-pot. A loop of quickmatch extends into the bore of the central tube and has its two ends carried out through the slots in the tube and through two of the holes in the lid. An ejection charge of gunpowder is retained in the recess in a central boss of each fire-pot by a paper disc, which is secured in position by shellac.
The tail cone fits over the flange of the base adapter and is held assembled to the bomb body by a tail nut, which screws onto the rear end of the tail tube against a tail adapter. The tail adapter fits into the rear end of the tail cone.
The striker pellet has a sharp point at the forward end and is held in the safe position by a shear wire passed through holes in the striker pellet and tail tube. The ends of the shear wire are soldered to prevent removal. The rear end of the striker pellet receives the forward threaded end of the safety rod. The creep spring is house in the forward end of the tail tube and bears against the cap holder and the striker pellet. The safety rod passes through the tail tube and is screwed into the threaded bore of the striker pellet.
The Bomb Mk II has only a slight difference in the tail plate.
Parachute Attachment: Either a Parachute Attachment No.1 Mk I or a No.1 Mk II may be used with this bomb. The Attachment No.1 Mk I consists of a small parachute housed in a container of sheet metal, consisting of a cylindrical housing plate and a cover. It fits loosely in the cylindrical strut of the bomb tail. The chute is 15 inches in diameter and vented at the peak. The Attachment No.1 Mk II is similar, except that it is housed in a collapsible cardboard container between cardboard packing discs.
Striker Attachment: There are two striker attachments, the No.1 Mk I, and the No.1 Mk II. No.1 Mk I consists of a coupling fork, snatch rod, striker rod, coupling socket, and a retaining sleeve, which houses a spring. The No.1 Mk II is similar, except that the coupling fork is fitted with a quick-release pin.
Functioning: Whent he bomb using the Parachute and Striker Attachments No.1 Mk I is released, the cover pulls the chute out. The chute opens and pulls the snatch rod against the action of the spring until the striker rod retaining balls escape into the annular recess in the retaining sleeve. The striker rod then moves down against the striker pellet. On impact, the inertia of the rod and pellet combine to shear the shear wire, overcome the creep spring, and pierce the ignition cap, igniting the blowing charge and blowing the base adapter and complete tail and parachute assembly from the body tube. The quickmatch, which passes through the lid and into the central tube of the rearmost magnesium alloy fire-pot, is also ignited, and, in turn, the quickmatch ignites the delay charges in and around the central tube of the fire-pot.
While the central tube delay charge is burning through, the outer delay charge initiates the surrounding priming charge, which, in turn, ignites the incendiary composition around it. Meanwhile, the central delay charge burns through and fires the ejection charge in the base of the fire-pot. This has the effect of ejecting the activated fire-pot from the bomb and also igniting the quickmatch of the second fire-pot, etc. Each ejected fire-pot will continue to burn for approximately 10 minutes; the magnesium alloy container and lid being consumed.
Finally, the quickmatch in the lod closing the nose of the bomb is ignited by the last ejection charge and initiates the priming charge, which, in turn, ignites the incendiary composition of the nose, and provides an additional fire source.
When used with the Parachute and Striker Attachment No.1 Mk II, the parachute is blown out of the cylindrical shroud on the tail and the chute opens, freeing the striker mechanism. Functioning after this is the same as that with Attachments No.1 Mk I.
Suspension: The bombs may be carried in a Small Bomb Container, or from a bomb carrier by a lug on a suspension band.
Explosive Components:
Filling: 1lb Thermite, and 5lb, 4oz Magnesium
IB 250lb Mks I and II (Obsolete)
Overall length (w/o fuze): 61 inches (approx.)
Body length: 34.1 inches
Body diameter: 12 inches
Tail length: 27.2 inches
Tail width: 11.7 inches
Fuel weight: 68 pounds
Tail length: 27.2 inches
Tail width: 11.7 inches
Fuel weight: 68 pounds
Total weight: 193 pounds
Fuzing: Nose Fuze No.36 Mk II with Ejector Charge No.2 Mk I
Tail No.: No.1 Mk I
Fuzing: Nose Fuze No.36 Mk II with Ejector Charge No.2 Mk I
Tail No.: No.1 Mk I
Color and markings: Red overall,
two 2-inch black bands separated by a 2-inch bright red band near nose.
two 2-inch black bands separated by a 2-inch bright red band near nose.
Description: The bomb has a cylindrical body with a hemispherical nose and parallel sides. An ejector-charge container is screwed and cemented into the nose and takes the nose fuze. The tail consists of a tail cone and a cylindrical strut attached to the cone by four fins. The after end of the body is closed by a tail plate, which is lightly secured to the body.
Functioning: On impact, the fuze functions and ignites the gunpowder ejection charge, which in turn ignites the incendiary filling and ejects it with the tail and tail plate.
Suspension: The bomb is suspended by a single suspension lug.
Filling: The Bomb Mk I is filled with a phosphorus-rubber-benzene mixture. The Bomb Mk II is filled with a "sticky flammable liquid." The ejector charge consists of black powder.
Functioning: On impact, the fuze functions and ignites the gunpowder ejection charge, which in turn ignites the incendiary filling and ejects it with the tail and tail plate.
Suspension: The bomb is suspended by a single suspension lug.
Filling: The Bomb Mk I is filled with a phosphorus-rubber-benzene mixture. The Bomb Mk II is filled with a "sticky flammable liquid." The ejector charge consists of black powder.
Remarks: This bomb was intended primarily for attacking forested areas, and can be dropped from heights up to 8,000 feet.
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