British Explosive Ordnance - Cluster Projectiles Part 2

British Explosive Ordnance

Cluster Projectile 500lb No.14 Mk I (Service)

Contents: One hundred and six 4lb incendiary bombs
Overall length: 67 inches
Body diameter: 14 inches
Tail length: 21 inches
Tail diameter: 14 inches
Total weight: 450 pounds

Fuzing: Nose Fuze No.42 Mk IV
Tail No.: No.42 Mk I
  

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

  

Description: The cluster comprises two fagots of 53 bombs each.  The bombs in the two fagots are arranged nose-to-tail, and with their safety plungers inwards so that hey are all depressed.  The bombs are held in place by a front end plate and a rear end plate, a top beam and a bottom beam, four wooden slats, tensioning straps, and a retaining bar having lateral pins which engage tabs on the tensioning straps.  A shear wire passes through a bridge and the retaining bar at a position near the rear end plate.  A channel, secured to the rear end plate, supports a fuze adapter, the outer end of which is closed by a transit plug fitted with a leather washer.  Inside the adapter is a piston through which a pin is arranged to engage the lower end of a pivoted lever.  The fuze adapter and the piston are slotted to receive the lever.  The upper end of the lever is forked and is connected 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 rear end plate to receive one end of a tail tie rod when the tail unit is fitted to the cluster.  A nose cover is fitted to the front end plate to decrease the drag of the cluster.
 

Tail Construction: The Tail Unit No.42 Mk I is a shortened drum-type tail, having a tail cone to which a tail ring is secured by fins.  At the base of the tail cone are two holes to fit over the dowels on the rear end plate of the cluster.  The tail unit is fitted with a bearing for an arming spindle, so that, if it should ever be required to fuze the cluster with an air armed fuze, a suitable arming spindle with an arming vane could be readily fitted.  Also, to provide against this contingency, a bracket to receive a safety wire is welded to the tail cone and a hole passes through a projection on the support for the arming-spindle bearings.  A tie rod passes through the center of the tail, and one end of the rod is screw threaded to go into the central nut of the rear end plate.  Two windows, one of which is open, are provided in the tail cone.  The open window is provided so that when the cluster is prepared for use, the fuzing link, connected to the pull percussion mechanism of the Fuze No.42 Mk IV, can be passed through it and connected to the fuzing unit of the bomb carrier.


Functioning: When a cluster is released from an aircraft, the fuze functions, and after a period of delay during which the cluster projectile falls freely, the fuze magazine charge 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 to break its shear wire, and to move so that the pins on the bar disengage the tabs on the tensioning straps.  The straps then fly outwards and the cluster disintegrates, the component parts failing away separately.  The individual 4lb bombs function on impact.


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

 

Cluster Projectile 750lb No.15 Mk I (Service)
   

Contents: One hundred and fifty eight 4lb incendiary bombs
Overall length: 67 inches
Body diameter: 17.3 inches
Tail length: 21 inches
Tail diameter: 17.8 inches
Total weight: 668 pounds

Fuzing: Nose Fuze No. 42 Mk IV
Tail No.: No.42 Mk I

  

Color and markings: Dull red overall, one tensioning strap painted bright red

  

Description: This cluster comprises two fagots of 79 bombs each.  The bombs in each fagot are arranged nose-to-tail with their safety plungers inwards so that they are all depressed.  The bombs are held in place by a front end plate and a rear end plate, a top beam and a bottom beam, four wooden slats, tensioning straps, and a retaining bar having lateral pins which engage tabs in the tensioning straps.  A shear wire passes through a bridge and the retaining bar at a position near the end plate.  A channel secured to the rear end plate supports a fuze adapter, the outer end of which is closed by a transit plug fitted with a leather washer.  Inside the adapter is a piston through which is a pin arranged to engage the lower end of a pivoted lever.  The fuze adapter and the piston are slotted to receive the level.  The upper end of the lever is forked and is connected 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 rear end plate to receive one end of a tail tie rod when the tail unit is fitted to the cluster.  A nose cover is fitted to the front end plate to decrease the drag of the cluster.


Tail Construction: The Tail Unit No.42 Mk I is a shortened drum-type tail, having a tail cone to which a tail strut is secured by fins.  At the base of the tail cone are two holes designed to fit over the dowels on the rear end plate of the cluster.  The tail unit is fitted with a bearing for an arming spindle so that, if it should ever be required to fuze the cluster with an air armed fuze, a suitable arming spindle with an arming vane could be readily fitted.  Two windows, one of which is open, are provided in the tail cone.  The open window is provided so that, when the cluster is prepared for use, the fuzing link connected to the pull-percussion mechanism of the Fuze No.42 Mk IV can be passes through it and be connected to the fuzing unit of the bomb carrier.


Functioning: When a fuzed cluster projectile is released, the fuze functions, and, after a delay during which the cluster projectile falls freely, the fuze magazine charge 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.  This causes the retaining bar to break its shear wire and to be moved so that the pins on the bar disengage the taps on the tensioning straps.  The straps then fly outwards and the cluster disintegrates, the component parts falling away separately.  The individual 4lb bombs function on impact.


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

Cluster Projectiles 1,000lb No.16 Mk II (Service)
  

Contents: Two hundred and thirty five 4lb incendiary bombs
Overall length: 73.5 inches (approx.)
Body diameter: 18 inches (approx.)
Total weight: 935 pounds 

Fuzing: Nose Fuze No. 42 Mk IV
Tail No.: No.48 Mks II and III

  

Color and markings: Dull red overall, one tensioning strap painted bright red

  

Description: This cluster consists of three fagots of 4lb incendiary bombs.  The bombs in each fagot are arranged nose-to-tail with their safety plungers inwards so that they are all depressed.  The bombs are held in place by a front end plate, a rear end plate, a top and bottom beam, four wooden slats, tensioning straps, and a retaining bar.  The retaining bar has a series of lateral pins which engage tabs on the tensioning straps.  A shear wire passes through a bridge and the retaining bar at a position near the front end plate.  A channel secured to the rear end plate supports a fuze adapter, the outer end of which is closed by a transit plug fitted with a leather washer.  Inside the adapter is a piston, through which a pin is passed, arranged to engage the lower end of a pivoted lever.  The fuze adapter and the piston are slotted to receive the level.  The upper end of the lever is forked and is connected to the retaining bar.  A nose cover is fitted to the front end plate to decrease the drag of the cluster.  The tail unit is attached to a spring-loaded rod extending through the center of the cluster.  the tail is held compressed against the spring by an arming wire arrangement.


Tail Construction: The Tail No.48 Mk II and III is of the telescopic type and is supplied fitted to the cluster in the closed position.  It consists of five fairings, forming a shortened cone, carried by the rear end plate of the cluster, and a strut mounted on supports, carried by an inner tube which slides in an intermediate tube.  The intermediate tube extends through the whole length of the outer tube, which is secured to the end plate of the cluster.  The intermediate tube replaces the central bomb of the middle and tail-end fagot of the cluster.

A spring is housed in the inner tube, with one end bearing against a stop in the tube and the other end bearing against a cap which closes the inner end of the intermediate tube.  The spring, which is under compression, tends to slide the inner tube out of the intermediate tube to extend the tail.  This movement is limited by a ferrule on the inner tube, which engages a ferrule in the intermediate tube when the tail is fully extended.

The inner and intermediate tubes have holes provided in them, which register when the tail is closed.  A safety wire is threaded through the holes to retain the tail in its closed position against the action of the spring.  A 4-ft fuzing lanyard is attached to the eye of the safety wire by a shackle, and a similar shackle is provided at the free end of the lanyard.


Functioning: When a fuzed cluster projectile is released from the plane, the arming wire is withdrawn, starting the delay of the fuze and releasing the tail unit, which then springs out on its rod to the fully extended position.  When the fuze functions, the fuze magazine charge is fired and the pressure of the gases forces the piston in the fuze adapter against the lower end of the pivoted lever.  The lever is thus rocked about on its pivot and exerts a pull on the retaining bar of the cluster.  This causes the retaining bar to break its shear wire and to be moved so that the pins on the bar disengage themselves from the tabs of the tensioning straps.  The straps then fly outward, and the cluster disintegrates, scattering the bombs, which fall away separately.  The individual incendiary bombs function on impact.


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


Remarks: The fagot at the nose end of the cluster contains 79 bombs.  The central and tail fagot contains 78 bombs each, the central bomb of each of these fagots being removed to allow insertion of the outer tube, which accommodates the stem of the tail and is secured to the rear end plate of the cluster.

 

Cluster Projectile 500lb No.17 Mk II (Service)

Contents: Twenty six 20lb fragmentation bombs, specially designed for use in this cluster
Overall length: 63 inches (with blunt nose)
Width across flats: 15 inches (octagonal in shape)
Tail length: 27 inches
Total diameter: 17.5 inches
Total weight: 582 pounds 

Fuzing: Tail Fuze No.885 Mk I
Tail No.: No.63 Mks I and II

  

Color and markings: Dark green overall

  

Description: The cluster comprises twenty-six 20lb fragmentation bombs arranged in two fagots of thirteen bombs each.  The bombs are held in place by a front end palte and a rear end plate, a top beam and a bottom beam, side plates, which overlap each other, and tensioning straps and a retaining bar, which hold the components together.  The bombs are completely enclosed.  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.  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 lower end of the lever.  The lever passes into the fuze adapter.  Links connect the upper end of the lever to a downwardly projecting plate, welded 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 to receive 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 either a blunt nose fairing or a streamlined nose fairing in position, and a nut welded to the center of the plate to receive the securing stud of the blunt nose fairing, or the tie rod of the streamlined fairing.  The blunt nose fairing is fitted to the cluster if it is to be carried internally in an aircraft.  The streamlined nose fairing consists of a hollow metal dome, the base of which is partly covered by an end plate welded to the dome, and is to be fitted to the cluster when carried externally on an aircraft.


Tail Construction: The Tail Unit No.63 Mk I consists of a tail cone, having an approximately octagonal base and a tail strut secured to the cone by six supports.  The tail unit has an arming spindle mounted in bearings, and has a fork at its inner end and an arming vane at its outer end.  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 to a cluster fuzed with a Tail Fuze No.855.  The Tail No.63 Mk I is only used when the cluster is carried internally in an aircraft.  The Tail No.63 Mk II is similar to the Mk I, except that it is generally strengthened and has seven tail drum supports as compared with the six of the Tail No.63 Mk I, and is to be used when the cluster is carried externally on the aircraft.


Functioning: When the fuzed cluster projectile is released, the fuze functions, and, after a period of delay during which the cluster 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 tensioning straps.  The straps then fly outwards and the cluster disintegrates.  Its component parts fall away separately and the individual bombs descend, supported by their parachute, to function in the normal manner.


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

Cluster Projectile 350lb No.23 Mk I, and 500lb No.24 Mk I (Service)

  
350lb No.23 Mk I

Contents: Fourteen modified US 20lb fragmentation bombs
Overall length: 62.25 inches
Body diameter: 11.1 inches
Tail length: 27.5 inches
Tail diameter: 12.6 inches
Total weight: 335 pounds 

Fuzing: Tail Fuze No.885 Mk I
Tail No.: No.65 Mk I

500lb No.24 Mk I

Contents: Twenty modified US 20lb fragmentation bombs
Overall length (blunt nose): 62.25 inches
Overall length (streamlined nose): 71.75 inches
Body diameter: 14.5 inches
Tail length: 30.5 inches
Tail diameter: 18 inches
Total weight: 467 pounds 

Fuzing: Tail Fuze No.885 Mk I
Tail No.: No.66 Mk I

  

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

  

Description: These clusters are identical in construction, and function in a similar manner.  The Cluster No.23 Mk I, however, is approximately hexagonal in cross-section, while the No.24 Mk I is roughly octagonal.


The bombs forming the cluster are retained in two fagots of 7 bombs each in the No.23 and 10 bombs each in the No.24 by means of top and bottom beams, front and rear end plates, side fairing, and four tensioning straps.  The tensioning straps are held in position by lateral pegs on the release rod, which is carried on the top beam.  The release rod is connected to a lever and piston mechanism, the cylinder of which also forms an adapter for the barometric fuze and is located on the rear end plate.  Before the fuze is fitted, the adapter is closed by a washered plug.

The cluster is converted into an amiable cluster by the addition of a blunt nose fairing and a drum-type tail.  A special streamlined nose fairing is designed only for the Cluster No.24 Mk I, when it is to be stowed externally on the aircraft.

Tail Construction: The Tail Unit No.66 Mk I of the Cluster No.24 consists of a tail cone having an approximately octagonal base to which a circular strut is attached by seven tail fins.  The cone is fitted with the conventional arming assembly consisting of arming vanes, arming spindle, and an arming fork.  The tail is fastened to the cluster by a tie rod, and has two dowel holes in its base to position it.  The cone is fitted with two inspection windows.

The Tail Unit No.65 Mk I is similar to the No.66 Mk I except that it has a hexagonal base, and only six tail pins.


Functioning: On release from the aircraft, the cluster falls until the fuze functions.  The explosion in the magazine forces the piston forward in its housing and causes a rocking movement 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 bombs.


Suspension: A British type suspension lug is fitted to the top beam, and two crutching pads bolted to the beam are used when a British type bomb carrier is fitted to the cluster.  Two sets of four tapped holes are provided in the top beam for the attachment of American type suspension lugs.  Two of the four holes at the nose end of the beam normally house the bolts securing one of the crutching pads to the beam.  If American type lugs are fitted, the British type lug and crutching pads must first be removed.

Nose Ejection Clusters

  

General Information: Experts have long strived to obtain a better type of cluster projectile, because of the inherent problems of aiming accuracy, dispersion of contents, weight factor, etc., presented by this type of ordnance.  The British believe that the solution to the search lies in the use of the Nose Ejection type cluster described herein, or its successor as modified by further research.

Nose ejection clusters were put into production near the end of World War II.  The information presented here is a generalized summary of nose ejection clusters, due to the fact that many of the individual clusters of this type are still in the developmental stage. 

  

General Requirements: The fundamental requirement of any cluster is to provide a means of placing cluster contents effectively on the target, the effectiveness being regarded broadly as a function of the angle and velocity of strike, functioning of fuzes or strikers, density of pattern, and accuracy of aim.  Complementary requirements of equal importance are that the cluster shall provide an economical aircraft bomb load, that its preparation for use shall be simple and speedy, that it will withstand road, rail, and ship transport without endangering its safety or usefulness, and that it will meet the strength requirements specified for carriage of bombs in British and American aircraft.

The type of nose ejection cluster now being developed and in production goes far towards meeting these requirements in a simple and direct manner.  It is not possible to generalize on the stability of nose ejection clusters as a group, since this depends on weight and dimensional characteristics, which are mainly due to the type of cluster contents carried.  Ballistic stability resulting in an aiming error of between 2 and 6 mils is being obtained, and will be improved upon as the development of folding and telescopic tails progresses.

The effectiveness of cluster contents from nose ejection clusters is largely fortuitous.  It appears to depend mainly on the inherent stability of the cluster contents and the parent cluster, although the velocity and height of disintegration of the cluster has some bearing.  Control of cluster velocity at disintegration is a problem now being explored.  Earlier investigation showed that decreased velocity at disintegration is invariably accompanied by a closing in of the scatter pattern, and much work on the control of the scatter pattern remains to be done.

Increasing the size of scatter patterns by means of attachments to the cluster contents and asymmetric parasheets is being investigated, but the results so far obtained, though promising, do not justify immediate embodiment.
 


Body Construction: The cluster body consists of a cylindrical steel shell made from 10- or 12-gauge steel plate, and is closed at the rear end by a steel plate of similar gauge, which is welded in position.  Two fuze pockets, which are deep enough to accommodate the burster ejectors, are attached to the end plate, which also embodies a centrally tapped hole for attaching the cluster tail.  A test plug, by which air pressure is applied at the filling factory to check that the rubber sealing joints in the nose are properly tight, is also provided in this plate.  The end plate is shaped to form a shallow truncated cone, the sloping surface of which locates the tail centrally on the cluster body.  The nose end of the cluster is closed by an iron casting secured in place by a number of screws.  On the inside of the casting is an internal steel squash plate secured by a central screw.  Its purpose is to compress the rubber sealing ring against the internal surface of the cluster body to exclude air.  A knife is attached at the front end of the cluster for the purpose of cutting the steel straps as the fagot of cluster contents is ejected.  A pressure plate is assembled in the cluster behind the fagot of cluster contents.  Suspension lugs for British and American type bomb stowage are permanently attached to the cluster body.

The cluster is designed, manufactured, and tested to withstand the climatic conditions experienced in the Far East.  After assembly at the filling factory, the rubber sealing joints in the nose and under the knife fixing screws are tested for tightness by an air-pressure test.


Tail Construction: Two types of cluster tail are in use, the conventional type with a tail cone and cylindrical strut, and one having collapsible fins, which is used where the space available is too small to permit the use of a norm-type tail.  Twin arming mechanisms are locked by means of fuzing wires engaging holes in the arming vanes.  Windows are provided through which the fuze can be observed as the tail is assembled to the cluster.  The tail is located on the tapered end plate of the cluster body, and is secured by a single central bolt.  It is designed, manufactured, and boxed for use in tropical climates.


Transit Bases: To prevent the cluster from sustaining damage affecting the safety of its contents, or destroying the hermetic seal in the nose, each cluster is fitted with transit bases which are intended to remain in position until the cluster is prepared for use.

The transit bases consist of two light-gauge steel rings filled with a material designed to withstand shock loads resulting from rough handling, and also to distribute the load over a large area of the cluster and so prevent damage to the nose seal, which would inevitably result from a blow concentrated at any one point on the nose cover.  The material used in the Mk I design is a resin-bonded sawdust, which is light in weight and resistant to tropical climatic conditions, fungi and insect growth, etc.  The bases are fitted one at each end of the cluster, and secured by tie rods, which embody a quick release device designed to enable the bases to be removed in a minimum of time.


Fuzing: One fuze and burster only are necessary to disintegrate the cluster, but two of each are used as an insurance against complete failure.  Clusters containing 4lb I.B.'s are fuzed with two Tail Fuzes No.42 Mk IV, while all others use two Barometric Tail Fuzes No.886.


Burster Ejectors: Ejection of the cluster contents in effected by a burster ejector, which is ignited by the cluster fuze.  The bursters are placed in the cluster at the time of fuzing.  There are two types of burster, the No.6 Mk I containing 70 grams of G.20 powder for large clusters and the No.7 Mk I containing 50 grams of G.20 powder for the smaller clusters.  The powder is contained in a plastic cylinder manufactured from a polyvinal chloride.  This material is fully resistant to tropical conditions and does not affect the gunpowder.  The cylinders are provided with two small extrusions by which they can be removed from the cluster if required.

For transport and storage the bursters are packed two or four (according to suze) in a sealed metal cylinder, 18 of which are packed in one wooden box.  The metal cylinders are opened by means of a tear-off metal strip.


Contents: The cluster contents are assembled in two or more banks of bombs, with light-gauge steel end plates and longitudinal steel struts, to form a fagot, which is firmly secured by a number of circumferential steel straps.  When properly assembled to a fagot, the cluster contents are safe and the fuzes cannot arm accidentally.  Damage to components of the cluster contents by the force of the ejector charge is prevented by the steel struts, which transmit the force of the explosion from the pressure plate directly to the nose cover, and not through the bombs themselves.


Functioning: On release from the aircraft, the fuzing lanyards are withdrawn from the fuzes and from the air arming vanes.  When a folding tail is used, the lanyard is also withdrawn from the retaining device to allow the tail to assume an expanded position.  At a predetermined height the fuzes operate and ignite the burster.  The expanding gases from the burster drive the fagot of contents forward.  As the fagot passes the cutting edge of the knife, the steel straps binding the cluster are severed, and the screws holding the cluster noose in place are broken.  The contents are then fully ejected.


Developmental Priority: The following is a list of nose ejection clusters in order of their development priority.  The first six items were cleared for production on 7 July, 1945.

Cluster N.E., ANM 69 I.B., 500lb. Mks I & II
Cluster N.E., 18-lb Mg. I.B., 800lb. Mk I
Cluster N.E., J 20-lb I.B., 800lb. Mk I
Cluster N.E., ANM 40 H.E., 600lb. Mk I
Cluster N.E., ANM 40 H.E., 350lb. Mk I
Cluster N.E., F. 8-lb H.E., 550lb. Mk I
Cluster N.E., F. 8-lb H.E., 350lb. Mk I
Cluster N.E., F. 8-lb H.E., 1,000lb. Mk I
Cluster N.E., ANM 69 I.B., 550lb. Mk III
Cluster N.E., 4-lb I.B., 800lb. Mk I
Cluster N.E., J. 30-lb I.B., 500lb. Mk I
Cluster N.E., 4-lb I.B., 500lb. Mk I
Cluster N.E., 4-lb I.B., 950lb. Mk I
Cluster N.E., ANM 69 I.B., 1,000lb. Mk I
Cluster N.E., 3-lb I.B., 1,000lb. Mk I

Next Time: High Explosive Rockets Part 1

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 - Aircraft Pyrotechnics Part 2

British Explosive Ordnance

  

Smoke Float No.1 Mks II, III, IV, and IVZ (Service)

   

Overall length: 22 inches
Body diameter: 6 inches
Total weight: 11.5 pounds
Burning time: 6 minutes
Color of smoke: White

Fuzing: Tail Pistol No.23
  

Color and markings: Body, head, and nose painted green,
tail cone vanes and strut painted yellow,
red ring 1/2-inch wide around head near nose.

  

Description: The Smoke Float No. 1 Mk IV comprises a cylindrical body, closed at one end by a conical head and a heavy nose.  A retarding band is secured to the body adjacent to the head.  A tail cone, carrying three vanes to support the vane ring, is secured to the opposite end of the body.  The end of the tail cone houses a pistol adapter for the tail pistol, which is locked in place by a grub screw.  Inserted in the pistol adapter is a cup, containing a cartridge base and a small quantity of flash composition, sealed with a paper disc.  A sleeve leads from the bottom of the pistol adapter into the funnel-shaped upper end of the tube, known as the container cap tube. 

The container for the smoke composition has a fusible cup inserted into the top of the smoke composition, which is filled with pressed priming composition, and a primed cambric disc through which is threaded a length of quickmatch.  The cylinder, provided with a ring of holes, surrounds the container.  The rest of the body and the tail cone comprise a buoyancy chamber.  The tail cone is provided with a sinking disc, which is scored, so that if a floating smoke float is found, the disc can be easily pierced to sink the float, the water entering the tail cone and passing into the body through the holes in the central cylinder.


   
Functioning: When the fuzed smoke float has been dropped from the aircraft, impact of the nose on the surface of the water causes the striker of the pistol to hit the cartridge base, and the ensuing flash ignites the flash composition.  The flash from the flash composition passes down the container cap tube and ignites the primed cambric disc and quickmatch, which ignite the primings.  The fusible cup melts, and the primings ignite the smoke composition.  Smoke rises up the container cap tube, and as the pressure increases, bursts the seal of the tail cone.  The short period between impact with the water and bursting of the seal is sufficient to enable the smoke float, after submerging, to rise to the surface, owing to its buoyancy.



Suspension: A suspension lug provided on the body permits attachment of the smoke float to a Light Series Bomb Carrier.



Remarks: In the Float No.1 Mk II, the container cap tube serves only to carry smoke from the container to the sealed hole in the tail cone.  A length of safety fuze, giving a 20-sec delay, extends between the pistol adapter and the container.  In the Float No.1 Mk III, the container cap tube also serves only to carry the smoke from the container to the sealed hole in the tail cone.  A separate flash tube guides the flash from the flash composition to the container.  The Float No.1 Mk IVZ differs from the Float Mk IV only in the nature of the smoke composition used.

Should water, especially salt water, come into contact with the smoke composition, it is liable to spontaneous combustion due to chemical action.

Smoke Float No.2 Mks I and II (Obsolete)

Overall length: 45.5 inches
Body diameter: 13 inches
Total weight: 108 pounds (empty)

Duration of burning: 8-10 minutes

Fuzing: Tail Pistol No.48
  

Color and markings: Green overall, red band around nose, yellow band around tail.

  

Description: This float consists of a cylindrical body with a rounded nose containing the smoke composition.  The nose piece is riveted to a metal band passing around the body at the joint.  The rest of the body is cylindrical and contains a central well filled with primed cambric.  At the after end of the central well is the pistol well.  The body has several internal stiffening rings.



Functioning: When the fuzed float is dropped, the striker overcomes the creep spring on water impact, and fires a detonator located below the pistol in the pistol well.  The flash is carried to the smoke composition in the nose of the float by means of the primed cambric in the central well.



Suspension: The float is suspended by means of a single lug attached near the nose.



Remarks: The Float No.2 Mk I has its forward end reduced in diameter about 1 and 1/2-inch for a distance of about one foot.

 

Smoke Float No.3 Mk I (Obsolescent)
   

Overall length: 10.1 inches
Body diameter: 6.7 inches by 4.95 inches
Filling: Calcium magnesium phosphide

Color of smoke: Red

Duration of burning: 40 seconds

Fuzing: Pull-percussion igniter
  

Color and markings: Upper half of body is yellow,
lower half of body is green, with red band 1/2-inch wide 2 inches from bottom.

  

Description: The float consists of a thin metal body at the upper end of which six smoke-emission holes, covered by a fabric seal, are located.  A wire gauze washer, held in place by an upper and lower liner, divides the body into two portions, the upper portion comprising a buoyancy chamber, and the lower portion housing a number of large and small smoke pellets disposed around a pull-percussion igniter.  The large smoke pellets are arranged in tiers.  The pellets in the upper tier are each contained in a primed cambric cylinder.  Below the wire gauze washer, a primed cambric washer rests on the upper ends of the primed pellets, and strips of primed cambric cross over the igniter.  The igniter, which is secured to the body, includes a split-headed clutch which is movable lengthwise in the igniter body.  A whipcord becket is secured to the head of the clutch and threaded through a rubber disc.  The upper end of the clutch is sprung over one end of a striker, which is spring-loaded when the clutch is pulled out.  Opposite the free end of the striker is a percussion cap, and an anvil housed in an ignited plug screwed into the igniter body.  A length of safety fuse, enclosed in a tube, terminates in a capsule filled with igniter composition.

When the float is to be used, proceed as follows: Remove the adhesive tapes securing the covers and remove both covers.  Press in the center of the press-cap to release the cap, and then remove the cap.  Pull the whipcord becket and the clutch out of the float, and immediately throw the smoke float overboard to leeward.



Functioning: When the clutch is pulled out, the striker is released and fires the percussion cap.  The flash from the cap ignites the safety fuse, which fires the igniter composition in the capsule after a delay of not less than eight seconds.  The flash from the igniter composition is conveyed by the primed cambric strips and the primed cambric washer to the pellets in the upper tier.  The smoke produced raises the pressure in the buoyancy chamber until the pressure bursts the fabric seal, and the smoke escapes to the atmosphere through the smoke-emission holes.



Remarks: This smoke float is intended for use from an emergency dinghy after a forced landing has been made, to assist search planes.

Aluminum Sea Marker Mk I (Service)
  

Length: 4.5 inches
Width: 3.5 inches (square)

Weight: 1 pound

Fuzing: None; impact initiated
  

Color and markings: Aluminum overall

  

Description: The marker consists of a fragile, paper-side body of square cross section, fitted with wooden end pieces, and filled with aluminum powder.  The outside is coated with aluminum paint.  The body is surrounded by a loose cardboard sheath to protect it from damage while being handled.



Functioning: When the sea marker is dropped from a plane, the cardboard sheath separates from the marker, and the latter ruptures on impact with the sea, leaving a patch of aluminum powder floating on the surface.



Remarks: This marker contains no explosive.

   

Aluminum Sea Marker Mk III (Service)

Overall length: 23.12 inches
Body diameter: 4.4 inches
Total weight: 10.25 pounds

Fuzing: Simple impact striker
  

Color and markings: Aluminum overall

  

Description: The sea marker consists of a cylindrical tin-plate body and tail cone containing aluminum powder, and a detonator-burster charge, which explodes when the marker is dropped on the sea.  The body has an internal strengthening band near each end.  The tail cone is soldered to the body and carries the fnis to which a circular strut is secured.  At the other end, the body is closed by a steel diaphragm.  The diaphragm has a central opening, threaded to receive a plug, which carries a detonator-burster tube.  A nose is fitted to this diaphragm and secured in position by three set screws.  Screwed into the nose is a striker guide in which slides a striker needle, secured to a striker head which projects outside the nose.  When in its operative position, a transit safety pin engages with the striker head, preventing it from moving inwards.  A second safety pin is provided in the nose.  This pin is flanged and is spring-loaded outward, but normally is held in position by a split pin to which a withdrawal wire is secured.  A securing wire is passed through the eye of the split pin, around the head of the safety pin and the nose of the marker, and through a boring in the transit safety pin.



Functioning: When the sea marker has been prepared for use and dropped on the surface of the sea, impact of the striker head with the water drives the striker needle inwards and explodes the detonator-burster charge, which disrupts the body and tail cone and scatters the aluminum powder.

Aluminum Sea Marker Mk V (Service)
  

Overall length: 12.5 inches (telescoped); 20 inches (extended)
Body diameter: 3 inches

Total weight: 10 pounds
 

Fuzing: None; impact initiated
  

Color and markings: Aluminum overall

  

Description: The sea marker body has an inner case of sheet metal, the lower end of which is pressed on to a heavy, aperture head.  The aperture in the head is sealed by a paper disc and is traversed by a pin.  A circular retaining piece is secured to the upper end of the inner case.  Inside the inner case is a fabric bag containing aluminum powder, each end of the bag being tied with thread to close it.  The thread at the lower end of the fabric bag is passed around a pin, to hold the bag in contact with the head.  An outer case slides over the inner case.  At its upper end the outer case is closed by two millboard discs, and inside its lower end a circular retaining piece is secured to provide a stop to prevent its being withdrawn completely from the inner case.  A cutter is provided immediately below the millboard discs.  The cutter is a ring secured inside the outer case and cut across in four places at about 45 degrees.  The cut ends are bent up at right angles to form four sharp projections with the outer case.



Functioning: The head is the heaviest part of the marker and consequently will strike the water first when dropped.  Impact with the surface of the water breaks the paper disc sealing the aperture in the head.  Water enters this aperture and carries the fabric bag rearwards from the head, breaking the thread which anchors it to the pin and also ejecting the millboard discs sealing the aperture at the tail end of the outer case.  As the bag passes through this aperture it strikes the sharp projecting parts of the cutter, which slit it, releasing its contents.  As a result, a slick of aluminum powder is formed on the surface of the sea.



Remarks: This marker contains no explosive.

Smoke Generator No.6 Mks I and II (Service)

Overall length: 7.13 inches
Body diameter: 2.42 inches

Total weight: 1 pound
Emission time: 2 and 1/2 minutes
Smoke Color: Orange
 

Fuzing: Percussion igniter
  

Color and markings: Light green overall

  

Description: The generator consists of a cylindrical metal body containing smoke composition in a metal foil cup, a quantity of priming composition, and a length of quickmatch.  When prepared for use, a percussion igniter replaces the adapter plug.  A tail unit is formed integrally with the body, and the upper end of the body is closed by a lid.  The igniter consists of an igniter body, a striker supported above the cartridge base by a shear wire, and a safety pin.  The cartridge base includes a small quantity of cap composition located between a percussion cap and an anvil.



Functioning: The safety pin is removed just before the generator is dropped.  On impact the striker moves downwards, breaks the shear wire, and fires the cap composition in the cartridge base.  The flash from the cap composition ignites the quickmatch, which, in turn, ignites the priming composition in the adapter.  The priming composition ignites the igniter composition, which then ignites the smoke composition.  The heat due to the combustion of the smoke composition loosens the metal discs covering the smoke-emission holes in the top lid, and the pressure of the smoke forces the discs off the top lid, allowing the smoke to escape to the atmosphere.



Remarks: This smoke generator is designed to be dropped from an aircraft to enable the pilot to ascertain the direction of the wind on the ground before making an emergency landing.

Next Time: Cluster Projectiles Part 1