Showing posts with label Air Defense. Show all posts
Showing posts with label Air Defense. Show all posts

Sunday, 19 March 2017

British Explosive Ordnance - Rocket Flares, Wire-Barrage and Pyrotechnic Rockets







British Explosive Ordnance





 Rocket Flares Introduction


This chapter is concerned with rocket assemblies which carry an illuminating candle.  A parachute may suspend the flare candle for purposes of illumination after ejection, as in the case of the 2-inch and 3-inch rocket flares, or the candle may not be either ejected or supported by a parachute, as in the case of the 2-inch target rocket, which merely furnishes a moving, visible target for anti-aircraft practice.

The section of the rocket flare containing the candle, parachute (if present), and initiating device, is called the flare head.  It corresponds to the "shell" in H.E. rockets.  The heads of the rocket flares discussed in this chapter are attached to the rocket motor by the conventional shell ring.






2-in UP Rocket Flare (Service)



Flare Head
Overall length: 22 inches (approx.)
Diameter: 2.25 inches
Total weight: 4.75 pounds
Fuzes used: Thermal Initiator


Rocket Motor:
Overall length: 31 inches (approx.)
Diameter: 2.25 inches
Width of fins: 2.375 inches
Total weight: 7.5 pounds
Propellant: Tubular cordite
Propellant weight: 2.5 pounds
Burning time at 60 degrees Fahrenheit: 0.9 seconds

  
General: This flare is used to illuminate enemy targets at night.  It is used in conjunction with medium-caliber guns.  A flare launcher is mounted on either side of the gun shield at a fixed angle of 30 degrees.  This arrangement makes it possible to keep a target illuminated and at the same time engage it with the main armament.


Description

Rocket Flare Head, 2-inch, No.1 Mks I and II, No.2 Mk I, and No.3 Mk I: The flare head consists of a cylindrical tinned-plate container, with two cannelures near the base.  Inserted in the container is a metal canister, which houses the illuminating candle and attached parachute assembly.  A ballistic cap is fitted to the forward end of the container, to which is secured with adhesive tape.  A base socket is secured to the other end of the container by indenting the cannelures.  The base socket screws into the shell ring of the rocket motor and contains the thermal ejector.  This latter consists of a steel base plate, in the center of which is a metal septum of accurately machined thickness.  The lower end of a length of safety fuze (primary delay), cut to burn approximately 22 seconds, makes contact with 2 and 1/2 grains of lead-dinitroresorcinate (LDNR), which is stemmed into the septum recess.  The upper end of the safety fuze extends into a magazine containing about 40 grains of G.12 gunpowder (primary ejection charge).  Protruding from the base end of the canister is a short length of safety fuze (secondary delay) cut to burn for 3 seconds.  The proximity to the primary ejection charge, and its upper end projects into a magazine containing about 40 grains of G.12 gunpowder (secondary ejection charge).

The different flare heads vary only in the contents ejector employed, as follows: Flare Head No.1 Mk I uses Ejector, Contents No.4 Mk I (with 22-sec delay); Flare Head No.1 Mk II uses Ejector, Contents, No.4 Mk II (with 18-sec delay); Flare Head No.2 Mk I uses Ejector, Contents, No.5 Mk I (with 9-sec delay); and Flare Head No.3 Mk I uses Ejector, Contents, No.8 Mk I.







Tail, Propelling, Rocket, 2-inch, Mks VI and VII: The Motor Mk VI is identical to the 2-inch Motor Mk III, except that the obturator of the latter is perforated, while that of the former is not, but rather is rust-proofed to allow free conduction of heat to the thermal fuze in the flare head.  For this reason, Motors Mk VI are marked T.I., indicating their use with thermal initiators.  No other motor may be used with the flare head.

The Motor Mk VII differs from the Mk VI in that the castellations in the charge are omitted and a metal cased cylindrical igniter is employed.


Operation: When the rocket is fired, heat from the burning propellant grain is transmitted through the head obturator and the thin septum of the thermal ejector, igniting the LDNR and initiating the lower end of the primary delay.  After a set delay, the primary ejection charge is ignited, and the canister is ejected from the container in a forward direction.  The secondary delay is initiated by the flash from the primary ejection charge, and, after three seconds, initiates the secondary ejection charge, which ignites the candle and ejects the parachute, cable, and candle in a forward direction from the canister.  The parachute opens when ejected from the canister, and the lighted flare candle is suspended in mid-air.

The purpose of the secondary delay is to allow the velocity of the canister to be reduced to a speed at which the flare and parachute assembly may be ejected without danger of break-up.

The flare is ejected at a range of about 5,000 yards and an altitude of about 2,000 feet.  The duration of burning of the flare is about 70 seconds.


Remarks: This flare, fitted with 4-inch by 1-inch fins, may be fired from a spiral launcher to obtain greater accuracy. 

The complete round (flare head and motor) weighs 12.25 pounds and measures 51 inches in overall length.






2-in UP Target Rocket (Service)
   


Target Head

Overall length: 15.75 inches
Diameter: 2.25 inches
Total weight: 4.5 pounds
Fuzing: Special igniter

  

Rocket Motor

Overall length: 20.25 inches
Diameter: 2.25inches
Width of fins: 2.375 inches
Total weight: 6 pounds
Propellant: Cogged cordite
Propellant weight: 1.25 pounds
Burning time: 0.45 seconds


  
General: This rocket is designed to give, by means of an integral flare, a visible aiming mark for anti-aircraft batteries.  The target has a range of about 5,000 yards at a speed of 250 to 400 knots.  The target can be used at night and is suitable for use from either aboard ship or ashore.





Description

Head, Rocket Target, 2-inch, Mk I: The target head consists of a thin sheet-metal container holding a flare candle.  Separated from the flare candle by a steel washer is an externally threaded spigot, by which the head is attached to the shell ring of the rocket motor.  The spigot is fixed to the target head body by means of a double crimp.  A weight is fitted into the forward end of the body and is fixed to the body by four screws.  A ballistic cap is crimped to the forward end of the weight.

Four holes are drilled through the body and the weight just before the flare candle, and a similar set of four holes is drilled abaft the candle through the body and the spigot.  The two sets of holes are covered with a strip of tape 1.5 inches wide, which is wrapped around the body.

An igniter mechanism, consisting of a diaphragm-operated striker, a percussion cap, and a gunpowder charge, is inserted into the after end of the spigot and is held in place by a threaded locking ring.






Tail, Propelling, Rocket Target, Mk I: This motor consists of a cylindrical steel body with a shell ring fixed in the forward end by eight locking pins held in engagement by a circular band spring.  Separated from the shell ring by a steel, flanged support ring, is an igniter in a cylindrical metal container.  Leads from the igniter extend through the central annulus of the cogged cordite grain to four automatic contacts fixed 45 degrees apart on the after end of the motor body.  A metal grid supports the cordite grain near the after end of the motor, and a thin metal obturator separates the grid from the venturi.  A bag of silica gel is placed in the venturi as a moisture-proofing measure.

This rocket motor must not be fired outside the temperature range of -5 to 130 degrees Fahrenheit.  Proposed new nomenclature for this motor is Motor, Rocket, 2-inch, No.4 Mk I.



Operation: Pressure of the gases from the burning cordite propellant grain passes forward into the spigot of the target head, reversing the diaphragm of the igniter.  This forces the striker into the percussion cap and ignites the gunpowder charge, which in turn initiates the flare composition.  The flare composition burns brightly, emitting light from the two sets of holes drilled in the body of the target head.









3-in Aircraft Rocket Flare (Service)
   


Flare Head
Overall length: 22.5 inches
Diameter: 5.45 inches
Total weight: 14.7 pounds
Candle power: 1,000,000
Burning time: 70 seconds
Time to primary ejection: 16 seconds
Time to light up: 19 seconds

Range to light up:
-4,800 yards when fired from ground
-5,600 yards when fire from aircraft at 140 knots



General: This head is designed for use with 3-inch A/C Rocket Motors, and may be fired either from aircraft or from ground launchers.
  


Description: The 3-inch A/C Flare Head Mk I consists of an outer body assembly and an inner canister.  The inner canister is brought to an ogive at its forward end to serve as a ballistic cap.  A parachute, enclosed in a cardboard housing, is contained in the upper portion of the inner canister.  The long cylindrical portion of the canister is then brought down inside the main body assembly, and tabs on the bottom edge of the canister are then bent over a metal lid, retaining the lid in position.  The lid consists of a metal disc, perforated in the center to accommodate the ends of two lengths of safety fuze.  A baffle plate is located between the lid and the flare candle.  Lengths of quickmatch extend from the base of the candle through the center of the baffle plate and into a gunpowder charge located between the baffle plate and the metal lid.  This charge constitutes the secondary ejection charge.  The safety fuze leading to it is the secondary delay.

A socket is fixed to the lower part of the body assembly, and to the socket is welded a spigot.  The spigot is threaded externally to screw into the shell ring of the rocket motor, and is internally threaded to receive the Ejector, Contents, No.7 Mk I.  The contents ejector consists of a threaded body, housing a diaphragm-operated striker, a percussion cap, and a double length of safety fuze, which extends into a gunpowder charge.

A base fairing is loosely assembled over the lower portion of the body assembly.  The after end of the fairing is notched to form several tabs, and a metal clip is placed around these tabs and tightened to ensure a firm attachment to the rocket motor.  The fairing serves merely to cover the joint between the flare head and the rocket motor, enhancing the streamlining of the complete round.



Operation: The pressure of the propellant gases from the rocket motor reverses the diaphragm of the contents ejector, thus firing the cap and the safety fuze in the ejector.  After the expiration of this primary delay (16 seconds)_ the primary gunpowder ejector charge is fired, expelling the inner container from the flare body assembly.  The explosion of the primary charge also ignites the secondary delay.

When the secondary delay expires, the secondary ejection charge is initiated, which ignites the lengths of quickmatch beneath the flare candle, and blows the lid out of the after end of the inner container, bending back the tabs on the base of the container.

The flare candle and the parachute assembly are now free the fall out of the after end of the container.  The flare has been ignited by the flash from the lengths of quickmatch, and is suspended in mid-air by the open parachute.  The purpose of the primary delay and ejection charge is to allow the flare ample time to lose velocity sufficiently so that an undue strain will not be placed on the parachute.

The flare head is painted black overall with a 1/2-inch red band painted around the flare body near the base.


Remarks: This flare head may be employed with the following motors: Motor, Rocket, A/C, 3-inch (Rocket Flare) Mk I; Motor, Rocket, A/C, 3-inch No.1 Mk I; or Motor, Rocket, A/C, 3-inch, No.1 Mks II-IV.









Wire-Barrage Rockets Introduction


This chapter deals with four rockets, which are designed to erect a vertical barrage consisting of parachute-supported cables, or parachute-supported wires carrying H.E. bombs.  These devices provide a temporary lethal deterrent to planes employing low-level attacks or dive-bombing tactics, and are supposed either to destroy or damage the attacking planes, or to cause them to abandon the attack.





Apparatus A.D. Type B Mk I (Obsolescent)
   

Overall length: 37 inches
Diameter: 7 inches
Total weight: 37 pounds
Propellant: Tubular cordite
Propellant weight: 3.9 pounds
Charge igniter: Magnesium (S.R. 371)
Separating charge: 154 grains G.12 gunpowder
Mine wire: 1,000 feet of steel piano wire
Bomb: H.E., A.A.D., No.2 Mk I
Bomb weight: 1 pound
Explosive: C.E. (tetryl)
Explosive weight: 8 ounces




  
General: This rocket is employed to lay a curtain of aerial mines in the path of low-level or dive-bombing aircraft attacking a ship.





Description: The tail of the rocket consists of a center tube containing the propellant charge, the gases from which emerge through the venture to propel the projectile.  The propulsive force continues for about 1.5 seconds.  Around the center tube is fitted a fairing to which are attached tail fins, protected by a cylindrical shroud.  The electric igniter leads pass through the tail fins, enter the center body of the rocket, and lead to the electric igniter.  Connected in parallel to the igniter is an electrically fired time fuze, which burns through the ignite the separating charge.  The separating charge is fired after about 10 seconds of flight time, and ejects the contents of the rocket head, which consist of the bomb, the mine wire, and the parachutes.

Operation: When the separating charge is ignited, the outer container is ejected forward from the outer case by the pressure of the exploding charge against the pressure plate.  As soon as the outer container is clear of the outer case, the pressure plate and the lid fall clear.  The lid acts as a pilot parachute and withdraws the main parachute from the container.  The main parachute opens, and, since it is connected by a spring shock absorber to the inner container, it pulls the latter clear of the outer container, which continues to fall, paying out the coiled mine wire inside it as it falls.

Also attached to the outer container is a cord, which pulls out the arming wire of the bomb as the two containers separate.  This cord subsequently breaks away to clear the wire which is being paid out.  The upper end of the mine wire is attached to the bomb and jerks it clear of the retaining-spring clip in the inner container.  The bomb is then suspended from the shock absorber by a length of light cord, termed the weak link.  This cord is secured to the shock absorber at one end, and at the other to a length of heavy cord leading from the bomb to the 7 and 1/2-inch parachute carried in the inner container. The heavy cord is thus slack between the knot and the parachute.

When all the mine wire has been paid out, the bottom bundle, containing the 30-inch parachute, is withdrawn from the outer container.  The canvas bands which protect the bundle on its way out of the container are then pulled clear by the release cord, and the bottom bundle is left hanging from the wire.  This state is accomplished about eight seconds after separation of the outer container from the rocket.

When the mine wire is struck by an aircraft, the weak link between the bomb and the shock absorber breaks, and the 7 and 1/2-inch parachute is pulled clear of the inner container and springs open.  The tautening of the wire also rips the bag of the bottom bundle, and the bottom 30-inch parachute opens.  As the aircraft pushes the wire along, the bottom parachute acts as a drogue and drags the wire across the aircraft, pulling the bomb down into contact with it.

The Bomb No.2 Mk I consists of a light sheet-steel case filled with explosive and containing a striker, detonator, and self-destroying assembly.  When the arming pin is withdrawn, the detonator is forced by its spring into alignment with the striker.  Simultaneously the delay firing pin on the detonator carrier strikes the cap and a length of safety fuze is ignited.  When the bomb strikes the aircraft, the striker is forced in and fires the detonator, exploding the bomb instantaneously.  If the wire is not struck by the aircraft, the safety fuze will burn through and detonate the bomb after about 95 seconds.  Thus the bomb is self-destructive after about 1,250 feet of fall.


Remarks: The round should ne be subjected to temperatures in excess of 110 degrees Fahrenheit.









Apparatus A.D. Type D Mk III (Service)
   

Overall length: 34.25 inches
Maximum diameter: 3.45 inches
Time to eject: 5 seconds
Lethal period: 7 seconds
Visible deterrent: 12 seconds

  
General: This rocket is designed to erect lethal wires vertically over a ship in the path of low-level or dive-bombing aircraft.  The wire is carried into the air by a rocket and is suspended by a parachute, which is carried in a container in the head of the rocket motor.  A parachute on the lower end of the wire opens when a plane strikes the wire and offers sufficient resistance to throw the aircraft momentarily out of control or to cause it to break up.  The apparatus remains lethal until its lower parachute strikes the water, about 7 seconds after ejection of the upper parachute.  It continues to act as a visible deterrent for an additional 5 seconds by which time the upper parachute has fallen to an ineffective height.




Description: The rocket consists of a tube filled with rocket-propelling composition having a conical hole down the center.  This hole is aligned with that in a choke in the after end of the tube.  A length of quickmatch and a gunpowder burster charge are located in the forward end of the tube immediately below the parachute container.  The parachute container holds the folded parachute and is closed at the forward end by a metal cap.  The parachute is connected to the forward end of the rocket motor tube.

A steel bridle and a cable are attached to the motor tube.  The cable is fitted with a loop for attachment to the main cable from the lower canister.

The lower canister consists of a cylindrical or rectangular box, which contains about 400 feet of cable.  To the lower end of the cable is attached a 38-inch drag parachute.  The forward end of the cable is attached to the cable leading from the bridle on the rocket motor.

Operation: When the projector, loaded with rocket and cartridge, is fired, the flash from the cartridge ignites the rocket propellant composition, which propels the rocket along its trajectory.  As the rocket rises, it uncoils and carries with it the main cable from the lower container, which remains fixed to the rocket projector.  When the cable is completely uncoiled, it withdraws the drag parachute from the container.  This parachute is fitted with an explosive link arrangement, allowing the parachute to open 3 seconds after firing.

When the propellant composition is completely burned out, the length of quickmatch in the head of the tube is ignited and in turn initiates the gunpowder burster charge.  This charge ejects the upper parachute from its container, leaving the rocket tube and the wire cable suspended in the air.

When an aircraft strikes the wire, the lower parachute opens and offers sufficient resistance to throw the plane out of control or to cause it to break up.








Apparatus A.D. Type J Mks I, IA, and II (Service)
   

  
General: This rocket is designed to erect a lethal wire vertically over a ship in the path of low-level or dive-bombing aircraft.  The wire acts both to bring down the aircraft if it strikes the wire, and as a visible deterrent to force the aircraft to abandon the attack.





Description: The head canister is a light cylindrical metal container, into which is packed a 62-inch parachute, called the top parachute, the cords of which are firmly secured to the base of the head canister.  A thermal fuze is fitted into the head canister and consists of a pellet of LDNR, a length of safety fuze, and 100 grains of G.12 gunpowder, which acts as an ejection charge.

The Tails, Propelling, 2-inch, Mks IVA and VA are standard 2-inch rocket motors, with a rigid stirrup welded to their after end.  No fins are fitted to the motor.  Contained within the motor body is a tubular cordite grain, into the head of which is fitted an electrical igniter.  The after end of the motor is sealed off by a light metal closing disc, through which pass the ends of the igniter leads terminating in a two-pin plug.  The proposed new nomenclature for the rocket motors is Motor, Rocket, 2-inch, No.2 Mks I and II.

The main container is a cylindrical-shaped metal container about 14 inches in diameter, with a removable lid.  Inside the container are two smaller concentric tubes, the outer of which is cone-shaped, while the inner is cylindrical.  Also encased within the main container are 825 feet of wire, a fabric bag into which is packed a 62-inch diameter parachute called the lower parachute, and a 20-inch diameter parachute called the trail parachute.

The wire is coiled down between the cone-shaped cylinder and the main container, and swivels are attached to the top and bottom ends of the wire.  The bottom swivel is shackled to the ring at the foot of the cords of the lower parachute, with the ring just protruding through the fabric bag.  Cords which keep the bag closed are connected to the trail parachute by a weak cord connection and a rip cord.  The trail parachute and fabric bag are packed into the small central cylinder, and have the swivel passing through a special slot.  The cylinder is then sealed with a light metal lid.







Operation: The rocket is fired when the attacking plane is within about 800 yards of the ship.  The wire is fully run out of 3.5 seconds after firing, and pulls the lower parachute bundle and the trail parachute up out of the inner cylinder, the lid of which is ripped off by the bottom swivel as it is pulled up.  Meanwhile, the heat from the burning cordite grain ignites the LDNR pellet in the thermal fuze, and this in turn ignites the safety fuze.  The safety fuze burns for about 6.5 seconds and then initiates the gunpowder ejection charge, blowing off the top part of the head canister and allowing the top parachute to open.  This occurs at an altitude of about 1,100 feet.  The lower parachute, still wrapped in its bag, is suspended at the bottom of the wire, and the trail parachute, which is now open, is attached to the bundle by the weak cord connection and the rip cord. 

After the top parachute opens, the wire begins to fall at about 42 ft/sec.  Twelve seconds after firing, the bottom parachute enters the water.  As soon as this occurs, the wire ceases to be lethal, but it remains a visible deterrent for an additional 12 seconds, by which time the top parachute has fallen to an ineffective height.

If the plane strikes the wire during its lethal stages, the pull on the wire breaks the weak cord connection between the lower parachute and the trail parachute.  This allows the trail parachute to pull the rip cord on the bundle, opening the fabric bag and freeing the lower parachute.  The sudden jerk caused by the wind operating on the lower and top parachutes is sufficient to throw the plane momentarily out of control, or in some cases to cause it to break up.


Remarks: The round must not be fired outside of the temperature range of 0 to 120 degrees Fahrenheit, except motors marked "S.U./K." which may be fired within the range of -5 to 130 degrees Fahrenheit.

The Apparatus Mk I differs from the Mk II in that the ceiling height of the rocket is 800 feet, and the wire is only 600 feet long.







Apparatus A.D. Type L Mks I, IA, II, and IIA (Service)
   


Canister length: 32.7 inches (approx.)
Canister diameter: 6.8 inches
Motor length: 31 inches (approx.)
Motor diameter: 2.25 inches


Use: The purpose of the Type L apparatus is to lay a curtain of aerial mines in the path of low-level or dive-bombing aircraft.





Description: The Canister Mk I consists of a conical upper container, which is connected to the tail of a 2-inch rocket motor by a short rod and a stirrup.  In the upper container are a parachute to bring down the spent motor, etc., the main support parachute, a bomb steady parachute, and the bomb.  These items are all held in position by three retaining cords, which are controlled by an explosive link.

The swivel on the lower end of the bomb is connected to the top end of a 1,000 foot coil of steel piano wire, which is contained in the lower container.  The wire from the bomb passes to the top of the coil through a slot cut in the central tube.  The central tube is provided to aid in unspooling the wire and avoid failures due to kinking.  The lower end of the 1,000 foot coil of wire passes back through the slot in the central tube and is connected to a long, light shock absorber, whose lower end is attached to the drag parachute assembly.  This latter consists of a 32-inch drag parachute housed in a bag and prevented from opening on the initial jerk at pick-up by four retaining cords controlled by an explosive link.  The junction between the upper and lower containers is effected by crimping parts of the base of the upper container lightly over the top of the lower container.

The electric leads for igniting the electric delay fuzes extend from the base of the lower container and terminate in a two-pinned plug which fits into a socket on the projector.

The Bomb, H.E., A.A.D., No.8 Mk I consists of a light sheet-steel cylinder filled with explosive.  A detonator is held in a shutter which is normally kept out of alignment with the striker by a clock spring.  An arming vane is attached to the outside of the bomb casing, and this vane, by means of a pinion wheel, is enabled to move the shutter sufficiently to align the detonator with the striker.

The Tail, Propelling, 2-inch, Mks IVB and VB consists of a slightly modified 2-inch standard rocket motor.  A closing plug is placed in the shell ring, and the electric leads terminate in a two-pin plug, which engages a socket on the projector.  The propelling unit is connected to the canister assembly by a 12-inch steel stirrup and a steel connecting rod 18 inches long.  A quick-fastening bolt is provided in the top of the canister for rapid connection to the connecting rod.  The proposed new nomenclature for the motor is Motor, Rocket, 2-inch, No.3 Mks I and II.





Operation: When the projector switch is closed, the rocket itself and the delay fuzes on the upper and lower explosive links are ignited simultaneously.  The rocket motor tows the top container into the air, and the wire is unspooled from the lower container, which remains fixed on the projector.  At the end of unspooling, the drag parachute assembly is picked up, the snatch tension being kept within safe limits by the long shock absorber.  The upper and lower explosive links are timed to operate when the container has reached a height of about 2,000 feet.

On operation of the explosive link in the top container, the bomb and parachutes are released and pulled out of the container.  Ejection of the rocket-support parachute is facilitated by a very weak cord connection between the rocket-support parachute and the main parachute.  The operation of the lower explosive link removes the constraint from the drag parachute and leaves the parachute free to open when a plane makes contact with the wire.

When a plane hits the wire, the drag parachute opens, and the weak link securing the 6-foot support parachute will part.  The bomb is pulled downwards onto the wing of the plane by the drag parachute.  When the bomb strikes the aircraft, the striker is forced downwards by the universal striker ring, firing the detonator.


Remarks: This rocket should not be fired outside of the temperature range of 0-120 degrees Fahrenheit.

The Mk II canister is identical to the Mk I except that no shock absorber is fitted, one side of the slot in the central tube is slightly flared to assist unspooling, and the length of the piano wire coil is 1,500 feet instead of 1,000 feet.











Pyrotechnic Rockets Introduction


Pyrotechnic rockets are relatively small pyrotechnic items, similar in principle to the familiar sky-rocket, which are used mainly for signaling, line-carrying, and illumination.  In most cases they are fired from a hand projector.

These items generally use a type of construction in which the head and rocket tube are integral The rocket tube is filled with a propellant composition having a tapered, conical vent hole in its center to facilitate burning.  The after end of the tube is constricted, or contains a plug of narrower diameter than the rest of the tube in order to concentrate the expanding propellant gases.  The choke and a short length of the vent tube interior are coated with gunpowder to assist in ignition of the propellant.



Kite-Launching Rocket Mk II (Service)
   

Overall length: 10.25 inches
Maximum diameter: 1.25 inches


  
General: These rockets are used to enable kites to be raised easily from emergency dinghies.  They are fired from a 1-inch signal pistol fitted with a barrel extension.
  


Description: The main rocket propellant composition is contained in the case, the nose of which is closed by a wooden plug and a layer of clay.  The after end of the case houses a plaster-of-paris choke, which is covered by a millboard washer and a paper disc.  A conical vent in the rocket propellant is aligned with a hole through the choke.  The end of the vent nearest the choke is coated with gunpowder priming.

The rocket is fixed in a bridle having a hinged stirrup, to which is attached a 2-foot wire cable.  During flight, the cable end nearest the rocket is protected from heat by an asbestos sheath.  The free end of the cable carries a loop for connection with the kite tow-line.

The rocket is painted aluminum overall, with manufacturing and filling information stencilled on the case in black letters.


Operation: When the pistol, loaded with rocket and cartridge, is fired, the flash from the cartridge ignites the gunpowder priming in the rocket, and the priming ignites the rocket propellant composition.  The rocket travels upwards for a distance of about 200 feet until the kite flying line is almost paid out.  The kite-cover retaining pins, which are attached to the kite flying line, are then withdrawn.  The kite opens automatically, and the kite cover falls away.  The flying line then withdraws a split pin connecting the rocket tow-line to the top of the kite, and the rocket is separated from the kite.









1lb Signal Rocket Mk III (Service)
   

Overall length: 16.4 inches
Maximum diameter: 1.8 inches
Total weight: 1 pound
Color of stars: White
Number of stars: 28


General: This rocket is designed for day or night signalling.


Description: The components consist of a propellant-composition filled case, closed by a wooden plug, and an upper cylinder containing 28 white stars.

The case consists of a rolled paper tube choked near the lower end to form a vent and threaded below the choke to receive the wooden plug.  The tube is filled with rocket-propellant composition, the center of which has a conical cavity.  A clay filling plug with a tapered hole in its center is located in the top of the tube, and the recess and the face of the clay are primed with mealed black powder.  A small charge of rocket composition is dusted over the top face of the clay.  A clay plug with a tapered hole is located immediately above the choke.  The recess and the choke are primed with gunpowder.  A metal socket for accommodating the stick is glued to the outside of the case, and also bound to it with twine.

The cylinder consists of a rolled paper tube filled with 28 white stars.  It is closed at one end by a paper disc covered with a paper cone, and at the other end is attached to the case.  The joints are sealed with paper strips.

The rocket is painted olive drab and carries a white instructional label around the case.  Manufacturing and filling information is stencilled on the cylinder.


Operation: When the wooden plug is removed, the vent is exposed and the rocket is ignited by applying a lighted porfire to the vent.  When the major part of the rocket composition has burned, combustion spreads through the cavity and primed hole in the clay filling to the rocket composition in the cylinder, and thereby ignites and ejects the stars.  The burning stars are ejected at a height of about 900 feet and burn for about 9 seconds.










Buoyant Line-Carrying Rocket No.2 Mk I (Service)
   

Overall length: 28 inches
Maximum diameter: 2.75 inches
Total weight: 3.25 pounds


General: This rocket is fired from a hand-firing rocket projector, and is initiated by a 30-grain percussion cartridge.  The rocket is designed for rescue purposes on marine craft and for use by airfields situated in coastal areas as a means of contacting crews of aircraft which have crashed into the sea immediately after take-off.


Description: The rocket consists of a wooden head made in two halves, held together with screws, which engage the head of the rocket tube.  The rocket propellant composition is contained in the tube, the nose end of which is closed by a wooden plug and a clay plug.  The after end of the rocket tube houses a plaster-of-paris choke, which is covered by a millboard washer and an oiled paper disc.  A conical vent is formed in the rocket propellant composition in line with a  tapered hole in the choke.  The end of the vent nearest the choke and the hole in the choke are coated with gunpowder priming.

A bridle with a hinged stirrup is attached to the rocket, and a tail consisting of a wire cable about 3 feet long is secured to the stirrup.  The part of the tail nearest the rocket is protected from the heat of the burning rocket composition by an asbestos sheath.  The free end of the tail carries a loop for connecting to a buoyant line.

The buoyant line consists of 250 yards of orange colored cotton cord, which is specially treated so that it will float on water.  It is coiled in a square cardboard container whose lid is secured by adhesive tape.

The wooden head is painted yellow overall and filling and manufacturing information is stencilled on the head in black letters.


Operation: When the projector, loaded with rocket and cartridge, is fired, the flash from the cartridge ignites the gunpowder priming in the rocket and at the same time forces the rocket out of the projector.  The gunpowder priming ignites the rocket composition, which then takes over and propels the rocket along its trajectory.  The rocket draws the buoyant line out of its container, and, when expended, falls into the sea and floats on the surface.










3 and 3/4lb Illuminating Rocket No.2 Mk I (Service)
   

Overall length: 30 inches
Maximum diameter: 2.25 inches
Total weight: 3.75 pounds
Height of ejection: 750 feet
Burning time: 45 seconds
Candlepower: 180,000


  
General: This rocket is currently employed only by the Air/Sea Rescue Service to assist in sea rescue searches at night.  It is fired from a hand-firing projector, and is initiated by a 30-grain percussion cartridge.


Description: The rocket consists of a steel rocket tube containing a rocket-propelling composition, which has a conical cavity in the center.  The rocket tube is fitted at one end with a metal center.  The rocket tube is fitted at one end with a metal flare container housing a wooden plug, a flare candle, and a cotton parasheet attached to the candle by a wire strap.  Crimped into the other end of the tube is a wooden choke sealed by a paper disc.

Secured to the rocket tube is a steel bridle, which extends beyond the wooden choke and carries a hinged stirrup.  One end of a steel rope tail is screwed to the base of the stirrup.  The end of the tail is protected from the heat of the burning propellant composition by an asbestos sheath.  The other end of the tail is spliced to form a loop to which is attached a 12-foot hemp rope.  The rope is coiled into a paper envelope, which has a cotton loop attached to it.  The envelope, with the rope inside, is attached to the rocket by a rubber band when supplied.

The wooden plug in the flare container carries a recess which houses a small quantity of gunpowder and a length of quickmatch.  The quickmatch contacts both the gunpowder and the rocket composition.

The flare candle consists of a cardboard cylinder held in place in the flare container with cotton-wool packing, and closed at one end by a wooden block.  This block has a pin passing through it to take one end of the wire strap of the parasheet.  At the other end of the cardboard cylinder is secured a washer, housing a gunpowder charge which is held in place by a muslin disc.  Above this disc is placed a small amount of priming composition.  An illuminating composition fills the remainder of the candle.

The parasheet and the wire strap are packed into the flare container with packing cylinders, and the container is closed by a metal lid secured with adhesive tape.

The flare container is painted aluminum overall.  The filling and manufacturing information is stencilled on the container in black letters.


Operation: When the projector, loaded with rocket and cartridge, is fired, the explosion of the cartridge breaks the paper disc, and the flash passes through the choke and ignites the rocket-propellant composition.  The gases generated by the composition then take over and force the rocket along its trajectory.  When the rocket composition is almost burned through, it ignites the quickmatch.  The flash from the quickmatch initiates the gunpowder in the wooden block.  The flash from the gunpowder ignites the priming composition in the flare candle, which in turn fires the illuminating composition.  Simultaneously, the pressure of the gases from the exploding gunpowder forces the lid from the flare container, and ejects the ignited candle and its attached parachute.  The tail and the hemp rope act as flight stabilizers.









6 and 1/4lb Illuminating Rocket No.1 Mk I (Service)
   

Overall length: 22.5 inches
Maximum diameter: 3.5 inches
Total weight: 6.25 pounds
Height of ejection: 800 feet (approx.)
Burning time: 45 seconds (approx.)
Candlepower: 300,000


General: This rocket is currently used by the Royal Observer Corps to indicate the presence of low-flying enemy aircraft to patrolling fighters, and by the Air/Sea Rescue Service to assist in sea rescure searches at night.  The rocket is fired from a Type B Rocket Projector, Mk III or IV, using a 60-grain percussion cartridge.


Description: The rocket consists of a rocket tube, a sliding tail, and a flare container, which houses a burster charge, flare candle, and parachute.  The rocket tube is filled with a rocket propellant composition, having a conical cavity in the center, and is closed at one end by a gun-metal choke crimped in position.  The choke is closed by a paper seal.  At the other end of the rocket tube are a wooden block and a clay plug, with a hole to receive a length of quickmatch.  The flare container is crimped to a metal junction head secured by screws to the wooden block.  Housed in the junction head are a wooden washer, covered with primed cambric, and the burster charge, which is held in place by another wooden washer.

The flare candle consist of a rolled paper case, strengthened at one end by a tin-plate cup, and held in place by felt packing.  The strengthened end of the case contains a fusible metal cup having a central hole.  This cup houses a quantity of priming composition, which is held in place by a primed cambric disc and a paper washer.  The main illuminating composition of the candle is held in place by a millboard disc.  A suspension cup, riveted to the paper case, carries a piece of wire wrapped at both ends with adhesive tape.  One end of a wire strap is looped around the middle of the wire.  The other end of the wire strap is attached to a 36-inch parachute, which is packed into the flare container between a wooden washer, millboard spacers, and a wooden disc.  The top of the flare container is closed by a metal lid secured in place with adhesive tape.

The sliding tail is of the drum type.  When the rocket is fired, the tail slides along the rocket tube until arrested by the metal choke.  A leaf spring attached to one of the tail fins then holds the tail in the extended position.

The flare container is painted aluminum overall, with filling and manufacturing information stencilled on the container in black letters.


Operation: When the projector, loaded with rocket and cartridge, is fired, the explosion of the cartridge breaks the paper seal on the rocket choke, and the flash passes through the choke to ignite the rocket-propellant composition.  The gases generated by the burning propellant then carry the rocket along its trajectory.  When the rocket composition is almost burned through, it ignites the quickmatch and the primed cambric, which in turn fires the burster charge.  The flash from the burster charge ignites the flare candle and forces the lid from the flare container, ejecting the ignited candle and its attached parachute.









9lb Illuminating Rocket Mk II (Service)
   

Overall length: 36 inches
Maximum diameter: 6 inches
Total weight: 9 pounds
Height of ejection: 1500 feet (approx.)
Burning time: 60-70 seconds
Candlepower: 300,000

  
General: This rocket is currently used only by the Royal Observer Corps to indicate to patrolling fighters the presence of low-flying enemy aircraft.  The rocket is fired from a Type B Rocket Projector Mk IV, using a 60-grain percussion cartridge.


Description: The rocket consists of a steel rocket tube, a tail, and a metal flare container, which houses a parachute, flare candle, and burster charge.  The rocket tube is filled with a propellant composition, with a conical cavity in the center.  At one end of the rocket tube is a gun-metal choke crimped in position and closed with a paper disc.

At the other end of the steel tube is a clay plug provided with a flash hole.  The flare container is fastened with screws to a metal junction head, which houses the burster charge and a length of quickmatch.  The burster charge is held in position by a wooden washer, covered with primed cambric.  Attached to the flare container is a waterproof sleeve, which fits over the projector barrel to prevent rain from entering the barrel when the projector is loaded.

The flare candle consists of a rolled paper case, strengthened at one end by a tin-plate cap and held in place with felt packing.  The strengthened end of the cap contains a fusible metal cup having a central hole.  Housed in this cup are a quantity of gunpowder, priming composition, and two igniter pellets.  The gunpowder and priming composition are held in place by a muslin disc.

The main illuminating filling of the candle is pressed in position and held in place by a millboard disc.  A wooden block, resting on the millboard disc, has a central hole to receive one end of a wire strap, which is lopped around a metal rod passing through the wooden block.  The block is riveted to the paper case.  The other end of the wire strap is attached to a 36-inch parachute, packed in the flare container between a wooden washer, cardboard spacers, and a wooden disc.  The top of the flare container is closed by a metal lid secured to the container with adhesive tape.

The rocket is stabilized in flight by a tail secured to the rocket tube.  The tail consist of four fins attached to a bridle, which is fitted to the rocket tube.

The flare container is painted aluminum overall, with filling and manufacturing information stencilled on the container in black letters.


Operation: When the projector, loaded with rocket and cartridge, is fired, the flash from the cartridge breaks the paper sealing disc, passes through the choke and ignites the rocket-propellant composition, which then forces the rocket along its trajectory.  When the rocket composition is almost burned through, the flame passes through the flash hole and ignites the length of quickmatch and the burster charge.  The flash from the burster charge ignites the flare candle and forces the lid from the flare container, ejecting the ignited candle and its attached parachute.





Next Time: Hand, Rifle, and Anti-Tank Grenades

Monday, 9 January 2017

British Explosive Ordnance - Practice, Infantry Training, and Miscellaneous Bombs








British Explosive Ordnance







Practice Bombs Introduction


Included in this section are five sizes of practice bombs.  These are the only ones specifically designed for that purpose, although there are currently in use several practice bombs which are merely service bombs inert-loaded with sand, water, or a chalk/lime solution.  The standard practice bombs generally emit smoke as a spotting charge to indicate bombing accuracy.

Standard practice bombs are painted white overall with two light green bands painted around the center of the tail.  Inert-loaded service bombs used as practice are painted black.  Practice bombs containing an exploder have a red band painted around the rear portion of the body.







Practice 8lb, Mk I  (Service)

  
Overall length: 16 inches
Maximum body diameter: 4 inches
Total weight: 8 pounds (approx.)

Fuzing: None
  

Color and markings:  White overall,
two 1/2-inch green bands around after body.

  
Body Construction: The body consists of an asbestos cement cylinder, in the nose of which is cemented a glass flask containing about 1/2 pint of titanium tetrachloride.  The rear of the cylinder is hollow and acts as a tail unit.  A light metal suspension band is secured to the exterior of the bomb body.


Functioning: On impact, the bomb body and glass flask break up, releasing the titanium tetrachloride to form a smoke cloud.  The bomb contains no explosive.
  

Remarks: The bomb is designed for low-level training purposes against airfield targets, and is of such construction that it leaves no debris injurious to aircraft tires.






Practice 8.5lb Mks I, II, and III  (Service)

  
Overall length: 16 inches
Body length: 12 inches
Body diameter: 3 inches
Wall thickness: 0.5 inches
Tail length: 4 inches
Tail width: 3 inches
Total weight: 8.5 pounds

Fuzing: Integral simple impact arrangement with detonator burster No.28 Mk I
  

Color and markings:  White overall,
two 1/2-inch green bands 1/2 inches apart around after body.

  
Body Construction: The Bombs Mk I and Mk III have a molded plastic body, which is made in three parts: a nose section housing the striker, a center section housing the detonator burster and filling plug, and a rear section which is hollow and closed at the after end.  A perforated disc inside the rear section supports the end of the detonator burster holder.  The center part of the body is filled with lead-antimony balls, with the interstices between them, and all but a 10% air space in the rear section cone, filled with titanium tetrachloride, or gunpowder and magnesium turnings.

The striker head is retained in handling by a cotter pin, safety pin, and shear wire.  An annular groove inside the nose portion is filled with lead shot secured by wax.

The Bomb Mk II nose is fitted for an extension rod.


Tail Construction: The tail assembly consists of a tube molded into the rear section of the body, with a cylindrical strut attached to the tube by four fins.


Suspension: The bomb is suspended by a single suspension lug on a band, which fits in a groove in the body, and is secured in place by a securing screw.


Filling: Main filling:
Bombs Mk I and Mk II contain titanium tetrachloride, which, when exposed to the atmosphere, forms a cloud of white smoke, marking the point of impact.  The Bomb Mk III has a flash filling consisting of gunpowder, and magnesium turnings.
  

Remarks: This bomb is designed for use against certain targets where a bomb is required to break on impact without causing damage to the target.  Because of its low terminal velocity, the bomb is only suitable for low-altitude bombing.

The Bombs Mk I and Mk II have smoke charges for day use, while the Mk III has a flash filling for night use.



Practice 10lb Mk I (Service), Mk II (Obsolete), and Mk III (Service)
   

Overall length: 18 inches
Body diameter: 8 inches
Wall thickness: Solid body
Total weight: 10 pounds

Fuzing: Integral simple impact arrangement with detonator burster No.28 Mk I
  

Color and markings:  White overall,
two light green bands 1/2 inches wide around tail cone.

  
Body Construction: The bomb has a solid cast-iron nose with an axial bore housing the striker head and rod, with a guide bush threaded into the rear cavity, and integral rear threads to take the central plug.  The striker is retained by a cotter pin (removed when loaded on aircraft), safety pin, and shear wire extending through the striker rod and guide bush.  The central plug houses the central burster tube.


Tail Construction: The tail cone is closed at the rear by a conical tail plug, and at the front end by the central plug to which it is attached.  The central tube extends through the tail cone to the tail plug, and holds the detonator burster.  A tapped hole, fitted with a plug, is provided in the central plug for filling.  The tail tube, with four fins carrying a cylindrical strut, projects from the tail plug.  Its rear end is closed by a cap.


Suspension: The bomb is suspended by a single eyebolt, which screws into the bomb body opposite the cavity for suspension from a Light Series bomb carrier.


Filling:
-Smoke filling: Mk I: 1lb Titanium Tetrachloride, which forms a white cloud on exposure to atmosphere.
-Flash Filling: Mk III: 1lb mixture of gunpowder and magnesium turnings, which causes a brilliant white flash on detonation.
 

Remarks: The Bomb Mk I with its smoke filling is used for daytime practice operations.  The Bomb Mk III with its flash filling is used at night.  These bombs, because of the solid iron nose, should not be used against lightly armored targets.

Mk II had a plastic tail, but was not 'satisfactory'. so all were scrapped.


 



Practice 11.5lb Mk I (Service), and Mk II (Obsolete)
    

Overall length: 18 inches
Body diameter: 3 inches
Tail width: 3 inches
Total weight: 11.5 pounds

Fuzing: Integral simple impact arrangement with detonator burster No.28 Mk I

Color and markings:  White overall,
two 1/2-inch light green bands 1/2-inch apart around after body.

  
Description: The bomb consists of a nose casting, fitted with a striker assembly and a tail cone which constitutes a container for the filling, and is fitted with a central tube for a detonator burster.  The nose casting is made of iron, internally threaded at the rear to receive the spigot portion of a central plug which closes the forward end of the tail cone.  The interior of the nose is filled with lead, and has a clearance hole for the striker rod.  The striker is secured by a cotter pin (removed when loaded), a safety pin spring-loaded outward, and a shear wire through the guide brush.


Tail Construction: The sheet-metal tail cone, constituting the container for the filling, is closed at the rear by a conical steel tail plug and at the forward end by a central plug which screws into the rear of the nose casting.  A tapped hole is provided in the central plug for filling purposes.  Secured to the tail plug is a tail tube having four fins, which carry a cylindrical strut.  The tail tube is closed at the rear by a cap.


Suspension: The bomb is suspended by a single eyebolt, which threads into the bomb case.
  

Filling:
-Smoke filling: Mk I: 1lb Titanium Tetrachloride, which produces white smoke when the detonator burster breaks open the tail cone and exposes it to the atmosphere.
-Flash Filling: Mk III: 1lb mixture of gunpowder and magnesium turnings, producing a brilliant white flash on impact.


Remarks: The Bomb Mk I with smoke filling is used for daytime practice.  The flash-filled Mk I is used at night.

The Bomb Mk II is made in the US of bakelite, but have now been scrapped.








Practice 25lb Mks I and III (Obsolete), and Mks IV and V (Service)
    

Overall length: 22 inches
Body diameter: 4 inches
Total weight: 25 pounds (approx.)

Fuzing: Integral simple impact arrangement with detonator burster No.28 Mk I

Color and markings:  White overall,
Mk I has two 1/2-inch green bands on after body,
Mk III has two 1/2-inch black bands on after body, and one red band on nose.

  
Description: This bomb consists of a solid, cast-iron nose section bored centrally to house a striker head, to which are attached a long striker rod and striker.  A striker guide bush is threaded into the after end of the central bore.  A shear wire through the guide bush and the striker prevents the striker from contact with the detonator burster in the unarmed position.  During transit and normal handling, the striker also is retained by a split pin and a spring-loaded safety pin.  The split pin is removed when the bomb is loaded aboard the plane, and the safety pin is ejected when the bomb is released.


Tail Construction: The tail consists of a long tail cone, closed at the wider end by a central plug.  A central tube for the detonator burster passes through the tail cone.  Located in the central plug, slightly off-centre, is a filling pug through which the smoke or flash filling is inserted.  As in most British practice bombs, the filling is contained in what is actually a part of the tail portion of the bomb.  A tail tube is attached to the after end of the tail cone and supports a cylindrical shroud and four fins.  The central plug is threaded externally and screws into the after end of the cast iron nose section of the bomb.


Suspension: A single U-shaped suspension lug is provided to suspend this bomb.
  

Filling:
-Smoke filling: Mk I and Mk IV - Titanium Tetrachloride
-Flash Filling: Mk III and Mk V - Magnesium shavings and gunpowder, or calcium silicide and gunpowder.


Remarks: The smoke-filled bombs are used for daylight operations; the flash-filled at night.  Because of their solid cast-iron noses, these bombs should not be used against lightly armored targets.

The Bombs Mk I and Mk III are identical, except for the fillings.  The Mk IV, which replaces the Mk I, is similar to it in construction, but differs in the following respects:  The safety plunger and transit safety pin have been increased in diameter.  The plunger is retained by a flexible steel safety wire permanently attached to a safety collar which is threaded internally to accept the transit safety pin.  The transit safety pin is screwed into the safety collar, thus retaining the assembly firmly until the bomb is on the carrier.

The Bomb Mk V, which replaces the Mk III, is mechanically identical to the Mk IV, but differs in the filling.





  


Infantry Training Bombs Introduction


These bombs, of which there are two sizes, are used to train infantry units under simulated combat conditions.  The bomb casing is splinter-less, thus reducing the possibility of training injuries, but the noise and flash produced are comparable to those of the explosions of a medium-sized bomb. 

The bombs are fuzed with a pistol/detonator combination.  The 6lb bomb takes a Nose Pistol No.34, while the 60lb bomb takes a Nose Pistol No.42.

The bomb bodies are constructed of rolled pressed paper, and are closed by a pressed-paper head.




IT 6lb Mk I (Service)




Overall length: 20 inches
Body length: 20 inches
Body diameter: 3.8 inches
Total weight: 6 pounds (approx.)
Charge/Weight ratio: 33%

Fuzing: Nose Pistol No.34
  

Color and markings: Dark green overall,
1/2-inch red band 1 inch from nose,
1-inch light green band 4 inches from the nose.


Body Construction: The body consists of a rolled-paper cylinder shellacked internally and externally.  A the nose end an adapter is attached to a chamfered cardboard washer, and threaded internally to receive the pistol.  The main filling is held in the body between a paper cup amidships and two felt washers at the nose, which position the exploder.  The paper cup is supported by a cardboard washer, which is in turn supported by a split collar secured to the body by four rivets.


Tail Construction: No separate tail unit is used.  The empty after portion of the body serves as a tail.
 
Suspension: The bomb is suspended by a suspension lug on a band approximately six inches from the nose.
  

Explosive Components:
Exploders: 3 CE pellets, two of which are perforated

Filling: 2lb of CE TNT 30/70, or desensitized Pentolite Grade I


Remarks: This bomb is used to provide realistic bombing attacks on infantry undergoing training.  The bomb is splinterless, but the nose and flash are comparable to those of a medium-sized bomb used for dive bombing operations.







IT 60lb (Service)
  



Overall length: 36 inches (w/o fuze extension rod)
Body diameter: 10.6 inches
Total weight: 60 pounds (approx.)

Fuzing: Nose Pistol No.42
  

Color and markings: Dark green overall,
1/2-inch red band and 1-inch light green band around forward part of body.


Body Construction: The body and tail unit are in one piece, and are manufactured of rolled and pressed paper.  The rolled-paper charge container, containing pentolite, rests on a felt washer seated on a diaphragm in the body.  The head of the charge container is closed by a rolled-paper head which is pinned, shellacked, and taped in position.  The head is recessed to house the pistol adapter.  A 6-inch extension rod is fitted to the Nose Pistol No.42, by means of a spring washer, after the arming vane cap has been removed.


Suspension: The bomb is suspended by a single suspension lug approximately 10 inches from nose of bomb, which is secured to the bomb body by two bolts.
  

Explosive Components:
Exploder: 3 CE pellets


Filling: Pentolite

Remarks: This bomb is designed to be used in training operations of ground personnel, simulating realistic bombing attacks.



 





Miscellaneous Bombs Introduction


This chapter covers two bombs which do not fall within the regular classification system.  One bomb is the "Nickle" Leaflet bomb, which is a US Army M26 flare modified to carry propaganda leaflets.  The other bomb is the Type H, A.D. Apparatus, which is designed to provide aircraft with a defense against fixed gun fighter planes by laying a parachute-supported aerial mine in their path.  It is similar in principle of operation to several of the rocket-propelled A.D. apparatus.





"Nickle" Leaflet Bomb No.2 Mks I and II (Service)


Overall length: 47 inches
Body diameter: 8 inches
Total weight: 64 pounds
Filling: Propaganda leaflets

Fuzing: Nose Fuze No.860 Mk II
  

Color and markings: Grey overall; white stencilling


Body Construction: This bomb is an adaptation of a US Army Flare M26, whose purpose is to scatter large quantities of propaganda leaflets over enemy occupied territory.

The bomb consists of a light sheet-steel body, closed at the front end by a plastic transit plug, and at the after end by a light sheet-steel lid.  When the bomb is filled and ready for use, this lid is held in place by four soft steel tabs, which are welded at one end to the bomb body and have their free ends bent over the lid.  Four tail fins are secured to the after end of the bomb casing.

Inside the body is a wooden frame consisting of a block, which fits snuggly in the nose of the bomb but does not completely fill it, and three equispaced battens, each of which is secured at one end to the block.  These battens extend the full length of the bomb body between the block and the lids..  The leaflets are contained in the wooden frame between the battens.  The outer end of the block is recessed to locate an ejection charge containing 400 grains of G.12 gunpowder held in a muslin bag.

Since the bomb is an American weapon, it must be somewhat modified for British use.  A special brass adapter is threaded into the nose fuze pocket.  The adapter is internally threaded to receive the larger Fuze No.860 Mk II.  In the base of the adapter is located a charge of G.12 gunpowder, sealed at either end by a waterproof disc.

 
Suspension: The Bomb Mk I is designed only for aircraft having the American-type bomb stowage.  It is fitted with two American type lugs attached to suspension bands around the bomb body.  The Bomb Mk II is designed for suspension only in a Universal-type bomb carrier.  The bomb is fitted with both British- and American-type suspension lugs, but the American lugs have been moved out of position to fit beneath the standard crutching forks of the Universal-type carrier, and act as strengthening bands for the light-gauge steel body.


Functioning: When the fuzed bomb is released from the plane, it falls freely until the fuze functions, and the gunpowder in the adapter is initiated.  The flash from the gunpowder ignites the ejection charge, and the pressure from the explosion of the ejection charge forces the wooden frame containing the leaflets out of the after end of the bomb body.  The lid is thrown clear and the contents ejected from the tail.  After the ejection, the wooden frame falls end-over-end, and the leaflets fall out of the frame and scatter over the target.




Type H, A.D. Apparatus Mk II (Service)

 

Description: The apparatus consists of a housing canister, support parachute, bomb, steel cable, and towing parachute.

The cylindrical housing canister is a metal tube, the open end of which is closed by a lid.  A hinged metal flap is attached to the lid to insure its release when the apparatus is dropped.  A lid-retaining assembly holds the lid and its flap in place until the bomb is dropped.

The support parachute's shroud lines are tied to an attachment ring which is connected to the double snatch link of the bomb fuze by circlips.



The discus-shaped bomb has a central fuze hole, and a rolled edge to facilitate penetration.  The fuze is secured in place by a nut.  The bomb is filled with CE/TNT.

The fuze incorporates an all-ways acting striker mechanism, a double snatch link, and a CE filled magazine, which is screwed into the base of the fuze and closed by a plug.  This plug has an eye to which the cable is attached.  The fuze body houses a striker, creep spring, and shutter.  When the detonator in the shutter is held out of line with the striker by the striker point engaging a hole in the shutter, the fuze is unarmed.  If the striker point is withdrawn from  this hole, the shutter is moved into place by its spring and held in alignment by a spring-loaded locking pawl.  The striker is retained in the shutter hole against the pressure of its creep spring by a safety plunger, which is retained in position in the actuating rod by a headed rod.  A shear wire and the upper balls of the snatch link connect the headed rod and the actuating rod.  The flanged head of the actuating rod is housed in the fuze body.

The double snatch link consists of a body housing the actuating rod, which carries an upper and lower set of balls, a washer, sleeve, and compressed spring.  The upper balls bear on the washer, which presses against the upper end of the spring, and the lower set of balls bear against the under side of the flanged end of the sleeve.  The parachute attachment ring is joined to the snatch link body by two circlips. 

The support parachute, which is packed and held together with rubber bands so it will open only on sharp impact, is attached to the fuze eye by a one hundred foot cable.



Functioning: When the apparatus is released from the plane, the lid is blown off and, acting as a pilot chute, withdraws the support parachute, followed by the bomb, cable, and towing parachute.  The canister falls away and the cable assumes a vertical position.

The opening of the support parachute imparts a jerk to the double snatch link, which then releases the lower set of balls.  When the cable is completely unwound, the upper set of balls is ejected and the juncture of the fuze to the support parachute is transferred to the shear wire.

When the pursuing enemy plane collides with the cable, another jerk is transmitted to the bomb and support parachute.  The ends of the shear wire are cut by the snatch link washer, which then engages the headed rod, and again cuts the shear wire to release the safety rod and arm the fuze.  The support parachute and snatch link are then freed from the assemblage.  The shock of impact also opens the towing parachute, which prevents the cable from slipping over and away from the plane.  The bomb is whipped against the plane, and its hard edges penetrate the skin.  Penetration causes deflection of the actuating rod, which forces the striker into the detonator and explodes the bomb.


Next Time: Obsolete Bombs