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Monday 30 January 2017

British Explosive Ordnance - Flares and Photoflash Bombs







British Explosive Ordnance






Flares and Photoflash Bombs Introduction


This chapter includes the 4-inch, 4.5-inch, and 5.5-inch reconnaissance flares, the 7-inch hooded flare, the 4.5-inch photoflash bomb, and the 1.7-inch aircraft illuminator.


Reconnaissance flares are used as an aid in night reconnaissance, as an aid to night bombing, and to assist in emergency forced landings.  The general construction of these flares is the same, consisting of a flare body, a flare candle, and a parachute which supports the candle after the flare has functioned.  These flares can be stowed inside the aircraft and dropped from a launching chute, or they may be fitted to a bomb or flare carrier.  However, they are most commonly carried in Cluster Projectiles.

The hooded flare has the conventional flare body and parachute, and also a special flare candle to which an asbestos shield is attached.  This shield, which is folded when contained in the flare body and opens on ejection, deflects the intense glare from the burning candle downward.  This protects the vision of the personnel of the dropping plane, and allows much better observation.

Photoflash bombs are used to provide illumination for night photography.  They contain a flash composition, which explodes with a loud report and a vivid white flash to provide the intense, instantaneous illumination necessary for night photography.

Aircraft illuminators are small flares which contain illuminating stars, but no parachute.  They have a short, three-second period of illumination, and are used by intercepting aircraft for illuminating attacking enemy planes at night.


 
 


Aircraft Illuminator Flare No.1 Mks I and II (Service)
   

Overall length: 11 inches (Mk I); 11.2 inches (Mk II)
Body diameter: 1.7 inches
Total weight: 12 ounces (approx.)
Candlepower: 3,000,000
Burning time: 3 seconds (approx.)

Fuzing: Special, integral electrical fuze
  

Color and markings: Brown overall

  
Description: The flare consists of a cylindrical body, which houses three illuminating stars.  At the lower end of the body is a conical wooden nose, which insures easy entry of the flare into the funnel tube of an ignition chute.  The upper end of the body is closed by a wooden plug and a metal disc, the weight of which facilitates the passage of the flare through the chute and off-sets the up-draught and air drag as the flare leaves the aircraft.

Each star is primed at both ends and has a short strip of primed fabric wrapped around the star and held in position by two threads.  A long strip of primed fabric extends along the sides of the three stars is held in position by three additional threads, one around each star, at a position between the threads securing the short strip.

Between the metal disc and the top of the upper star is an aperture felt washer which contains a charge of gunpowder.  A primed fabric disc is located between the bottom of the lower star and the upper surface of the nose.  Vent holes are provided in the nose, whose open ends are sealed with paper sealing discs. 

Two copper strips pass along the outside of the body beneath a paper wrapper surrounding the body.  Their lower ends are connected to the leads from the electric fuze, and their upper ends emerge from, and are secured by, wire staples to the wrapper.  The portion of the outer surface of the paper wrapper surrounding the staples is sprayed with zinc to form contact bands.

The Flare No.1 Mk II is identical to the Flare Mk I, with the following exceptions.  The upper end of the body is closed by a metal cap, and the nose is made of moulded plastic material.  A pellet of delay composition is used instead of the length of delay safety fuze, and a length of quickmatch is located between the bottom of the lowest star and the priming composition.

   
Functioning: When the flare is launched through the ignition chute, the contact bands make rubbing contact with the spring wiper contacts in the chute, and the electric fuze is fired.  This fuze ignites the delay safety fuze, igniting the priming composition, which in turn fires the long primed fabric strip.  This strip initiates the short primed fabric strips, igniting the stars.  The gunpowder charge ejects the stars from the body.

When the Flare Mk II is launched, the electric fuze fires the pellet delay composition, initiating the priming composition.  This ignites the quickmatch, which in turn fires the long primed fabric strip.


Remarks: A delay of approximately two seconds occurs between the release of the flare and its ignition.








4-in Training Flare Mks I, III, IV, VII and VIII
 and 4-in Reconnaissance Flare, A.S. Mks I and II (Service)


Overall length: 30 inches
Body diameter: 4 inches
Tail diameter: 5.5 inches
Parachute diameter: 11 feet
Burning Time: AS flare, 50 seconds; Training flare, 3.25 minutes
Candlepower: Training flare, 500,000; A.S. flare, 2,000,000


Fuzing: Pull-percussion igniter
  

Color and markings:  Black with 1/2-inch red band near nose

  
Description: The 4-in Training Flare Body Mk IV comprises a front body portion containing a flare candle and a pull percussion igniter, and a rear body portion containing an 11-ft cotton parachute, which is connected with the candle unit.  The front and rear body portions are connected by a diaphragm, which closes one end of the front body and supports the flare candle and igniter.  Two suspension bolts on the diaphragm provide an anchorage for the parachute.  The opposite end of the front body is closed by a millboard disc held in place by a fusible closing disc.  In addition to the igniter plug, the igniter comprises an igniter body, which houses a striker mechanism, and into which the igniter plug is screwed.  The igniter body is held in place in the central tube by a retaining plate.

The A.S. Reconnaissance Flare is identical to the Training Flare except for a delay fuze below the igniter, which give about a 5-second delay before burning starts.


Functioning: When the flare is released, the long static cord, the free end of which has been attached to the rear crutch holder of the carrier or to the eyebolt on the lid of the launching chute, is withdrawn from the elastic loop and pulls the retaining pin out of the loop on one of the flaps, thus releasing all flaps.  The flare falls, with the parachute being drawn out of the body because of the connection between the short static cord and the long cord attached to the plane.  Tautening of the auxiliary static cord breaks the thin braided cord, separating the flare from the cord attached to the plane.

After the chute has opened, the body of the flare continues momentarily to fall freely until the suspension rope is fully tensioned.  The jerk as the suspension rope tightens causes the securing wire to bend and the clutch to be pulled out, spring-loading and releasing the striker.  The striker, when released, moves downwards and fires the percussion cap.  This flash ignites and fires the percussion cap.  This flash ignites the gunpowder in the training flare, sending a flash down the center tube by the primed cambric tube, igniting the burster charge.  (A percussion cap ignites the safety fuse in the A.S. flare.)  The flash from the burster charge passes through the holes in the apertured washer and ignites the primed cambric washer and the priming composition at the bottom of the flare candle.  The priming composition ignites the flare composition, being assisted by the six portions of igniter composition which ensure a substantially even ignition of the flare composition.  The fusible closing disc at the nose of the flare melts and permits the candle to burn freely.


Suspension: The flare has suspension band to which the lug is attached.


Remarks: The 4-inch Training Flare Mk I has a silk parachute, and a safety pin held by a split pin held by a split pin instead of a securing wire.  The flash from the gunpowder is conveyed to the burster charge by a length of instantaneous fuze instead of by a primed cambric tube as in the Flare Mk IV.  The 4-inch Training Flare Mk III has a silk parachute, but it is a stronger one than is used in the Flare Mk I.  The 4-inch Training Flare Mk VII has a slightly different cotton parachute than the Flare Mk IV.  The 4-inch Training Flare Mk VIII has an igniter fitted with a copper shear wire, which passes through holes near the top of the igniter body and in the clutch.  The shear wire is fitted to assist assembly during manufacture.  It is broken by the jerk which bends the securing wire and pulls out the clutch.  The parachute is similar to that of the Mk VII.

The 4-in A.S. Reconnaissance Flare Mk II has the same changes as 4-in Training Flare Mk VIII.

These flares are used primarily for training purposes, and, after being dropped from an aircraft, are supported by their parachutes even if they are not ignited.  The flares can also be used to assist in making an emergency landing during night flying.










4.5-inch Reconnaissance Flare Mks I, II, III, IV, and VII, and Target Flare Mk I (Service)
   

Overall length: 33 inches
Body diameter: 4.5 inches
Parachute diameter: 11 feet
Total weight: 23 pounds

Burning time: 3 to 4 minutes
Candlepower: 750,000


Fuzing: Nose Fuze No.35, 42, 848, or 849
May use No.28B Mks II or III, or No.860 with special permission.
  

Color and markings: Black overall with 1/2-inch red band around nose end

  
Description: The Flare Mk IV has a tubular body containing the candle unit, and a parachute, which is made of cotton.  The tail end of the body is closed by a closing dome, and has four tail fins.

The body is closed at the nose end by a diaphragm having a bush into which is screwed a nose plug or the fuze.  The flare composition is contained in a candle case together with some priming composition and a primed cambric disc at the nose end, a quantity of clay held between millboard discs, and a felt washer at the tail end.  A lid is riveted to the tail end of the candle case.  A shackle attached to the lid connects the candle unit with the suspension rope of the parachute.


Functioning: When the fuzed flare is released from the plane, the fuze is set in operation and the flare drops freely until the flash from the magazine charge of the fuze passes through the flash hole in the diaphragm and ignites the powder puff.  The gases formed by the burning of the gunpowder in the puff force the candle unit towards the closing dome.  The wooden slats push off the dome, thus permitting the candle unit and the parachute to be ejected from the flare body.  The flash from the puff ignites the primed cambric disc and the priming composition at the nose of the candle, and the priming composition ignites the flare composition.  The candle, which is now suspended on its parachute, continues to burn from the nose end until the flare composition is expended.


Suspension: A suspension band having two removable suspension lugs, one for attaching the flare to a Universal Bomb Carrier, and the other for attaching it to a Light Series bomb carrier, is secured to the flare body.  Seven flares may be carried in the Cluster No.1 Mk I, and four in SBC 250lb.


Remarks: The 4.5-inch Reconnaissance Flare Mk I is similar to the Flare Mk IV, but has larger tail fins, a Silk Parachute Mk II, a brass disc over the flash hole in the diaphragm, and a candle case which is not strengthened in the region through which the lid rivets pass.  The Reconnaissance Flare Mk II is similar to the Flare Mk IV, but has larger tail fins, a Silk Parachute Mk IV, a brass disc over the flash hole in the diaphragm, and a candle case which is not strengthened in the region through which the lid rivets pass.  The Reconnaissance Flare Mk III is similar to the Flare Mk IV, but it has larger tail fins and a brass disc over the flash hole in the diaphragm, and its candle case is not strengthened in the region through which the lid rivets pass.  The Reconnaissance Flare Mk VII is similar to the Flare Mk IV, but has a modified parachute known as the Parachute Mk VF.

The details of the Target Flare No.1 Mk I are generally the same as in the 4.5-inch Reconnaissance Flare Mk IV, except for the stencilled markings.  This flare is manufactured to give two types of steady colours, red or green, or four combinations of colors and stars; green with red stars, red with green stars, red with yellow stars, or green with yellow stars.  The red flare has a candlepower of approximately 250,000 while the green flare is rated at approximately 175,000 candlepower.  The flares themselves burn for approximately three minutes.  The stars, which burn for about 10 seconds, are ejected at intervals of approximately 20 seconds.









4.5-inch Reconnaissance Flare Mks V, VI, and VII (Service)
  
  
Overall length: 33 inches
Body diameter: 4.5 inches
Parachute diameter: 11 feet
Total weight: 23 pounds

Burning time: 3 to 4 minutes
Delay: 2 minutes
Candlepower: 750,000


Fuzing: Nose Fuze No.35, 42, 848, or 849; No.860 can be used only if specially authorized.
  

Color and markings: Black overall with 1/2-inch red band around nose end

  
Description: The Flare Mk V has a tubular body containing the candle unit and the Cotton Parachute Mk IVF.  The tail end of the body is closed by a closing dome, and has four tail fins.  The body is closed at the nose end by a diaphragm having a bush into which screws a nose fuze.  The flare composition is contained in a candle case, and at the nose end of the case is a quantity priming composition.  The filling of the candle is held in place at the nose end by a primed cambric disc and a millboard washer, and at the tail end by a felt washer and a lid secured to the candle case.  The lid is riveted to the candle case, and the rivets pass through a hessian or cotton canvas strengthening band around the candle case.  At the nose of the candle unit is a container in which is coiled a length of safety fuze, the ends of which are clamped and set in cement.  During manufacture, the end of the safety fuze which is ignited by the powder puff is cut square, dipped in moist powder.  The other or Inner end of the safety fuze terminates in a small quantity of igniter composition, and is covered by a shellacked paper tube and two shellacked paper discs.


Functioning: When the fuzed flare is released from a plane, the fuze is set in operation, and the flare drops freely until the magazine charge of the fuze bursts the paper disc covering the flash hole in the diaphragm.  The flash from the magazine charge passes through the flash hole and ignites the primed fabric of the powder puff and the strands of quickmatch, which in turn ignite the gunpowder in the powder puff.  The gases formed by the burning of the gunpowder in the powder puff force the candle unit toward the closing dome, thus permitting the candle unit and parachute to be ejected from the flare body.  The safety fuse is ignited by the flash from the gunpowder in the powder puff, and after a delay of two minutes, during which time the flare has fallen 2,000 feet supported by the parachute, the safety fuze ignites the igniter composition at its inner end.  The flash from the igniter composition is conveyed by the primed cambric disc to the candle primings, which are ignited and in turn ignite the flare composition.


Suspension: A suspension band around the body has two removable suspension lugs for attaching to a Universal Bomb Carrier, or a Light Series Bomb Carrier.  Seven flares may be contained in Cluster No.1 Mk I, and four in the 250lb SBC.


Remarks: The 4.5-inch Flare Mk VI is similar to the Flare Mk V, but is provided with a 4-minute internal delay, so that the flare falls 4,000 feet suspended on its parachute, before the candle is ignited.  The Flare Mk VIII differs from the Flare Mk V in that it has a modified parachute known as the 11-foot Parachute Mk VF.

The period of delay of these flares enables the aircraft which has released the flare to get into position for its bombing run and to make the best use of the three- to four-minute period of illumination given by the flare.








   


4.5-in Skymarker Flare No.1 Mks I, II, and III (Service)

  
Overall length: 33 inches
Body diameter: 4.5 inches
Parachute diameter: 11 feet
Total weight: 28 pounds (approx.)
Burning time: 100 seconds

Fuzing: Nose Fuze No.42, 848, or 849

Color and markings: Black overall with 1/2-inch red band near nose

  
Description: The flare has a tubular body containing the candle unit and the Parachute Mk V.  The tail end of the body is closed by a closing dome, and has four tail fins attached.  The nose end of the body is closed by a diaphragm to which a bush is secured.  The transit plug or the nose fuze is screwed into this bush.

A flash hole in the diaphragm is covered by a paper disc and gives access to a "powder puff" consisting of a primed cambric bag containing gunpowder.  The powder puff is secured to a perforated disc.  Its purpose is, with the aid of the perforated disc, to eject the candle unit and parachute from the flare body and to ignite the flare candle.

The candle unit comprises a steel container closed at the top by a lid and at the bottom by a dished washer.  In the container is a magnesium alloy candle body containing a small quantity of gunpowder, some priming composition, and a quantity of incendiary composition.  The hole in the washer is closed by a primed cambric disc.  The candle unit is held in place in the flare body by a felt washer, felt strips, and three wooden slats.  The slats extend beyond the top of the candle unit and the closing dome, and, when the flare is activated, push off the closing dome to permit the candle unit and parachute to move out of the flare body.  A shackle attached to the lid connects the candle unit to the suspension rope of the parachute.


Functioning: When the fuzed flare is released from the aircraft, the fuze is set in operation, and the flare falls freely until the magazine charge explodes.  The flash from the charge passes through the flash hole in the diaphragm and ignites the powder puff.  The gases formed by the burning of the gunpowder in the puff exert pressure on the under side of the perforated disc, forcing the candle unit toward the closing dome so that the wooden slats push off the dome.  The candle unit and parachute are ejected from the flare body.

The flash from the puff passes through the holes in the perforated disc to ignite the primed cambric disc and the gunpowder at the nose of the candle.  The gunpowder ignites the priming composition, which in turn ignites the incendiary composition.  As the incendiary composition burns, the magnesium alloy candle body also burns, and pieces of the burning candle fall away, giving the appearance of a vertical chain of white lights in the sky.


Suspension: A suspension band with two removable suspension lugs is secured to the flare body.  The lugs are secured to the suspension band by screws having a locking wire passing through their heads.  A crutch pad is also secured to the flare body.


Remarks: These flares are similar in external appearance to the 4.5-inch Reconnaissance Flare Mk IV.

The Flare Mk II is similar to the Mk I, except that, just below its lid, the candle unit is provided with a container filled with gunpowder.  This gunpowder is ignited by the incendiary composition and ejects any magnesium alloy which remains in the candle unit when the incendiary composition is expended.  This insures that odd pieces of burning magnesium alloy do not continue to fall after the flare has served its purpose.  The Flare Mk III is identical to the Mk II, except that the burning time has been increased to 120 seconds by use of a different type of incendiary composition, and of a steel container and magnesium alloy candle body which are 3 inches longer than those in the Flare Mk II.  The increased length of the candle unit is accommodated by reducing the space occupied by the parachute.











4.5-in Photoflash Bomb Mks I and II, and 4.5-in Heavy Photoflash Bomb (Service)


Overall length: 33 inches
Body diameter: 4.5 inches
Total weight: 19 pounds
Illumination time: 0.1 second (approx.)

Fuzing: Nose Fuze No.28B, 848, or 849; No.860 can be used only if specially authorized

Color and markings: Body black overall; tail red,
1/2-inch red band around nose end,
FLASH printed plainly on the body near the nose end.

   
Description: The Photoflash Bombs Mk I and Mk II are similarly constructed, the only difference being that the Mk II has narrower tail fins.  Each flash has a tubular body, closed at the tail by a closing dome and at the nose by a front diaphragm having a bush into which is screwed the nose fuze.  The four tail fins are located at the after end.  A quantity of flash composition is contained in the body between a front and rear diaphragm.  The filling hole is closed by a press-cap and overseal.  A central tube, closed at each end, extends between the front and rear diaphragms and is filled with gunpowder.  A socket secured to the front diaphragm houses a perforated disc, and a muslin disc, which closes the nose end of the central tube.  The perforated disc is held in position by a socket plug having a flash hole covered by a disc, which, in earlier issues, is made of brass, but in later issues is paper.


Functioning: When the fuzed bomb is released from an aircraft, its fuze is set in operation and the flash falls until the magazine charge of the fuze explodes.  The flash from the magazine charge passes through the perforated disc and ignites the gunpowder in the central tube.  The gunpowder explodes, bursts the body of the photographic flash, and simultaneously ignites the flash composition.
 

Suspension: The bomb is suspended by means of a suspension band to which are secured two suspension lugs, one for attaching to a Light Series Bomb Carrier, and the other for attaching to a Universal Bomb Carrier.

 
Remarks: These flash bombs are intended to provide illumination for night photography, and when activated they explode with a loud report and vivid white flash.  It is important to distinguish between flares and photoflash bombs.  They may be distinguished by the following characteristics.  FLASH is stencilled on the nose of all photoflash bombs, and the tail of the bomb is red.  Eight rivets are visible around the body at the junction of the red and black parts of the bomb.  On removal of the tail dome of a flash bomb, there is no parachute or shackle visible.

Externally, the 4.5-inch Heavy Photoflash Bomb is the same as the ordinary 4.5-inch photoflash.  Internally, the construction is slightly modified, as the rear diaphragm is moved to a position nearer the closing dome, consequently increasing the length of the central tube.  A retaining diaphragm is positioned in the body 5 and 1/2 inches from the front diaphragm.  A cast-iron weight is located between the front and retaining diaphragms, the flash composition being housed between the rear and retaining diaphragms.  The fuze is a US Mechanical Time Fuze Mk III which has a fuze adapter in order to fit it into the British bomb.  When it is loaded, the arming wire is fitted through the second hole in the arming wire is fitted through the second hole in the arming pin and passes through the arming vane lock.  The delay may be from 5 seconds to 93 seconds.  The heavy bomb weighs 40 pounds.






 




5.5-in Reconnaissance Flare Mk I and II (Obsolescent)


Overall length: 48 inches
Body diameter: 5.5 inches
Parachute diameter: 18 feet
Total weight: 41.5 pounds
Burning time: 3 minutes, 15 seconds to 4 minutes, 15 seconds
Candlepower: 1,000,000 (approx.)

Fuzing: Nose Fuze No.28B, 42, or 848; may use No.35 or 849; No.860 can be used only if specially authorized

Color and markings: Black overall with 1/2-inch red band 5 inches from the nose.

Description: The Flare Mk II has a tubular body, which contains the flare-candle unit and its parachute.  The body is closed at its nose end by a diaphragm having a bush into which is screwed a nose fuze.

The tail end of the body is closed by a closing dome and has four tail fins.  The diaphragm has a flash hole, sealed by a thin metal disc.  A powder puff, consisting of a primed fabric bag containing gunpowder and strands of quickmatch, is located in position by washers, and a perforated disc to which it is secured.  The candle unit comprises a candle case containing the flare composition and a quantity of priming composition.  The nose end of the case is closed by a primed cambric disc and a millboard washer, and the tail end is closed by a lid.  A shackle attached to the lid connects the candle unit with the suspension rope of the parachute.


Functioning: When the fuzed flare is released from a plane, the fuze is set in operation and the flare falls freely until the magazine charge of the fuze is fired and perforates the metal disc covering the flash hole in the diaphragm.  The flash from the magazine charge passes through the flash hole and ignites the primed fabric of the powder puff and the strands of quickmatch, which in turn ignites the gunpowder in the powder puff.  The gases formed by the burning of the gunpowder in the puff force the candle unit towards the closing dome, and the wooden slats push off the closing dome and permit the candle unit and parachute to be ejected from the flare body.  The parachute then opens and supports the candle unit.  Before ejection, the candle is ignited by the flash from the gunpowder in the powder puff; this flash being conveyed by the primed cambric disc at the nose end of the candle case to the priming composition, which, in turn, ignites the flare composition.

 
Suspension: A suspension band with lug is provided for attachment to a Universal Bomb Carrier.


Remarks: The 5.5-inch Reconnaissance Flare Mk I is similar to the Flare Mk II, except that the duration of burning is approximately 3.5 minutes, and a Parachute Mk I, which is not as strong, is used instead of a Mk II.








7-in Hooded Reconnaissance Flare No.1 Mk I, No.2 Mk I, No.3 Mk I, and No.4 Mk I (Service)


Overall length:
-No.1: 63 inches
-No.2, 3, and 4: 60 inches

Body diameter: 7 inches
Total weight: 85 pounds (approx.)
Burning time: 3 minutes to 4 minutes
Candlepower: 750,000

Fuzing:
-No.1: Nose Fuze No.848
-No.2, 3, and 4: Initiator No.C5 Mk I

Color and markings: Black overall with 1/2-inch red band 5 inches from the nose.

  
Description: The Flare No.1 consists of a flare-candle unit contained in a thin metal case, which is fitted with a heavy nose, and closed at the tail end by a metal closing cap.  Housed in the rear of the casing is the parachute attached by the shackle to the candle unit.  A metal tube containing a primed cambric tube connects the powder puff in the nose of the flare with the candle cap.  A length of safety fuze, sealed at each end with a celluloid cap containing a small gunpowder charge, passes through the candle cap to the gunpowder charge contained in the nose of the candle.  Attached to the side of the candle unit is a frame to which is fixed the sheet asbestos hood which directs the light downward and shields the eyes of the bombardier from the glare.  The form, which folds around the candle unit, has a square cross section when open and extends beyond the ends of the candle unit.  The tail end of the hood is partially closed by a deflector.

In the Flare No.2, the heavy nose and the suspension band are omitted, thereby reducing the weight.  The Flare No.3 is the same as the No.1 except that it incorporates a 2 and 1/2 minute delay; and the Flare No.4 is also the same as the No.1 except that it has three 14-foot parachutes.

 
Functioning: On release from the aircraft, the flare falls in a normal manner until the fuze forces the parachute and candle unit out of the metal case, at the same time igniting the primed cambric.  The primed cambric ignites the celluloid cap of the safety fuze, and after a short delay the safety fuze fires the gunpowder charge in the nose of the candle.  The explosion of the gunpowder forces off the candle cap, at the same time igniting the flare composition.  The short delay in the fuze allows the parachute and hood to open before the flare functions.

 
Suspension: The Flare No.1 is carried singly by a suspension lug on a band fastened around the body.  Flares No.2, 3, and 4 are carried in Cluster No.3 Mk I, four flares in each cluster.


Remarks: The Hooded Flares No.2, 3, and 4 are each fuzed with a 5-sec Delay Initiator No.C5 Mk I.  These initiators are ignited by the functioning of the cluster fuze to give simultaneous and individual initiation to each flare after the cluster has disintegrated.



 



Next Time: Aircraft Pyrotechnics Part 1

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