American Projectiles and Explosives - Drift Signals and Navy Flares (Part 1)

American Projectiles and Explosives

Aircraft Pyrotechnics







Day Drift Signal Mk 1

Length: 10 inches
Maximum diameter: 3.5 inches

Thickness of case: 0.07 inches
Color of slick: Chrome yellow


Use:  This signal may be used for a reference point for air navigation.


Description:  The case is composed of a water-proofed paper pulp shell pressed in the form of a tear drop, with four fins formed on the tail cone with a diameter approximately the same as the greatest diameter of the nose section.  The only other element of this signal is the very fine metallic powder filling which nearly fills the cavity.


Operation:  When the signal is dropped into the water, the shell breaks, allowing the powder filling to spread out on the surface and form a slick visible to 15,000 feet.


Remarks:  The Day Drift Signal Mk 1 is a Bureau of Aeronautics item.  This marker has replaced the Drift Signal M25, which is now obsolete.









Night Drift Signals AN-Mk 4 and AN-Mk 5 Mods 1 and 2; Aircraft Float Light Mk 6 Mods 0-2

AN-Mk 4
Length: 13 inches
Diameter: 3 inches
Weight: 2 pounds

Burning time: 3 to 3.5 minutes
Time from impact to ignition: 8 to 12 seconds
Release altitude: Under 500 feet
Visibility: Night - 6 to 7 miles



AN-Mk 5
Length: 19 inches
Diameter: 3 inches
Weight: 4 pounds

Burning time: 15 to 17 minutes
Time from impact to ignition: 8 to 12 seconds
Release altitude: Under 500 feet
Visibility: Night - 6 to 7 miles


Uses:  These signals are employed as follows:

-To determine the drift of the plane from which the signal was dropped.
-To mark an object to which an aircraft desires to call attention of a surface vessel.
-To determine the wind direction before landing.
-To mark the landing deck on aircraft carriers for night landings.
-To mark the location of the surface of the water for emergency night landings.


Description:  The Night Drift Signal AN-Mk 4 has an ogival shaped, die-cast nose with a lug on one side so that the signal will turn and not strike the bottom in shallow water, while the Night Drift Signal AN-Mk 5 Mod 1 has a flat die-cast nose.  In both cases the die-cast nose contains a water-impact fuze.  The bodies of both signals are made of hollow wooden cylinders, with one end tapered, on which the tail assembly is mounted.

The pyrotechnic mixture is formed into pellets approximately four inches long and 1.25 inches in diameter, with a 0.022-inch hole concentric with the longitudinal axis through which the delay fuse passes.  One pellet is used in the AN-Mk 4, and three pellets are used in the AN-Mk 5 Mod 1.  The pellets are enclosed in a pyrotechnic tube to keep the hygroscopic material from absorbing moisture through the wooden body.  Originally, pure tin was used for this purposed\l but in recent lots lead and zinc have been substituted.  The nose end of the signal is closed with a paraffin-treated sealing disc, while the tail is sealed with a metal cap.

Aircraft Float Light Mk 6 Mod 0 consists of four Drift Signals AN-Mk 5 Mod 1 which are contained in a square wooden body and burn successively.  The box is 20.25 inches long and 5.125 inches square.  The weight is 16 pounds, and the burning time is 45 minutes.  The float light is released by hand from an altitude of from 300 to 5,000 feet.  It gives off a grey smoke and a flame 10 or 12 inches high.  The Aircraft Float Light AN-Mk 6 Mod 2 is ignited by a pull igniter which is pulled when released.  The light can be dropped from an altitude over 5,000 feet.


Operation:  When launched from aircraft, the drift signal falls nose-down.  On impact with the surface of the water, the paraffined paper sealing disc is broken and the water drives the firing pin up against the primer.  The flame from the primer ignites the time fuze which runs the length of the hole through the center of the pyrotechnic pellets in order to give the drift signal enough time to return to the surface and right itself.  The time fuse ignites a length of quick match which, in turn ignites the starting mixture and then the pyrotechnic pellets.  The gases evolved by the pellets break open the pyrotechnic tube and force out the cap which seals the discharge tube in the tail.  A bright flame 12 to 15 inches high and a white smoke are produced.  These are visible for six to seven miles on a clear night.


Remarks: These signals may be used for day signals, but under certain conditions observation is difficult.

The Mod 2 is a moisture-proofed version of the Mod 1.

Retro-Rocket Drift Signals

No picture available

General: These 3-inch rockets are designed to be fired aft from a plane to eliminate the effect of forward motion, allowing the signal to fall straight down.  This is called retro-firing.


Description: The rockets have the 3-inch Heads Mk 5 Mod 1 and use the Motors Mk 2 or Mk 3.  With the Motor Mk 2, they weigh 4.8 pounds; with the Motor Mk 3, 4.6 pounds.  They use the Launcher Mk 2.


Operation:  Firing of the rocket motor initiates a delay train in the signal in the head, which delay sets off the flare 10 to 20 seconds later.  The motor separates from the head during the free fall, and the signal hits the water and floats on it, burning from 10 to 15 minutes.

Navy Flares

1 1/2 Minute Parachute Flare

No picture available

Length: 18.75 inches

Diameter: 2.24 inches
Weight: 4.31 pounds

Burning time: 1.5 minutes
Light intensity: 110,000 candlepower

Color: White
Maximum release altitude: 1,200 feet

Rate of fall after ignition: 550 feet/min

Use:  It is used to illuminate an area for emergency night landings by certain commercial-type aircraft in use by the Navy.

Description: The flare is issued in a hermetically sealed aluminum case called a projector tube.  One end of this tube is closed by a metal cap and sealed by a gasket. The other end narrows down into a small knob with an electrical terminal in the extreme end.  The tube is cylindrical for most of its length.

The projector tube contains an inner case and a propelling charge of black powder.  The inner case contains an ejection charge, the pyrotechnic candle, and a parachute.  The ejection charge is in the after end of the inner case, and the delay fuse and interrupter mechanism are mounted on the outside of the same end of the inner case.

The electrical terminal at the end of the projector tube is connected through a toggle switch in the pilot's compartment to the lighting system of the plane.


Releasing: The projector tube, which is constructed as an integral part of the flare, is fixed by clamp bands to a bracket in the after end of the fuselage, where the firing circuit is connected when the flares are loaded.  The projector tube remains in the bracket when the flare is released or expelled by closing the switch in the cockpit.

Operation:  When the electrical circuit is completed in the cockpit, the propelling charge is ignited and the inner case is forced out of the projector tube.  The propellant ignites the delay fuse, which burns until the inner case is approximately 40 feet from the plane and then, through an explosive lead-in, ignites the ejection charge which, in turn, forces the pyrotechnic candle and attached parachute from the inner case.  Simultaneously, the ejection charge ignites the candle.

An interrupter mechanism between the delay fuse and the ejection charge in the inner case prevents the functioning of the flare until the inner case has left the projector tube and is clear of the plane.

Remarks:  A proprietary item, this flare has a commercial designation of "1 1/2 Minute Parachute Flare Mk 1 Mod 1", but this Mark designation is not that of the Navy.

Mk 4 and Mods

  

Length: 25 inches

Diameter: 4.75 inches
Weight: 18 pounds

Burning time: 3 minutes
Light intensity: 300,000 candlepower

Color: White
Maximum release altitude: 1,200 - 5,000 feet

Rate of fall after ignition: 350 feet/min

Use: Primarily, this flare is used to illuminate an area to permit the landing of aircraft.  Occasionally, it is used for reconnoitering, bombing, and blinding anti-aircraft defenses.

Description: The complete flare consists of a parachute and illuminant contained in a shellac-impregnated chip-board tube closed at the ends by chip-board discs which are held in place by gummed cloth and sealed with paraffin.  There are two metal steadying bands fastened around the case, against which the steadying forks of the bomb rack rest.  The complete flare is issued in a waterproof metal container.

Operation:  The Navy Flare Mk 4 may be released from bomb racks or shackles, from an adapter, or manually.  As the flare is dropped from the plane, the arming plate of the rip cord is retained by the plane and the rip cord is pulled from the side of the flare case to which it is fastened by gummed cloth tape.  As the flare continues to fall, the rip cord, which is wound around a wooden spool inside the of the flare case, is unwound, tearing away the end of the flare case.  The end disc and spool fall away as the parachute tube is pulled from the flare case and retained by the rip cord.  The parachute is pulled out of its tube by the weigh of the illuminant and flare case, which causes the parachute and parachute shrouds to straighten out.  When the parachute and parachute shrouds are fully extended, a small cord attached to the release key pulls the release key down, allowing the rip cord to slip through the key, and the flare falls free.

An ignition wire is attached to the suspension cable in such a manner that it is pulled before the cable is fully extended.  Four friction wires are attached to the ignition and run through primer cups of match compound.  This ignites a double quick-match train, which burns down the outside of the illuminant case and ignites the primer composition, which, in turn, ignites the first fire and illuminant.  When the parachute opens, the illuminant is pulled out of the flare case, and flare case falls clear.  full suspension and ignition occur about 30 to 50 feet below the plane.

 

Next Time: Drift Signals and Navy Flares (Part 2)

British Explosive Ordnance - Aircraft Pyrotechnics Part 1

British Explosive Ordnance

Aircraft Pyrotechnics Introduction


This chapter includes data on flame floats, marine markers, smoke floats, sea markers, and smoke generators dropped from aircraft.

Flame floats and marine markers are devices designed to give off a flame to illuminate surrounding areas of water.  Generally calcium phosphide is used as the filler for flame floats.  When moistened, this chemical gives off phosphine, a gas spontaneously inflammable on contact with air.

Smoke floats generate smoke by the combustion of a smoke-composition filler.  The smoke so produced may be used for indicating a position, for obscurement, or for signalling.  Although all smoke floats are designed primarily for use at sea, they differ from each other in construction and design according to the purpose for which the smoke is intended.  There are three essential types of smoke floats in use, one fore each of the following purposes:  to mark a position at sea for navigational or bombing purposes; to create a smoke screen; and to be thrown by hand from a plane or dinghy to attract attention following a forced landing.

Sea markers are designed to be dropped at sea to produce a distinctive surface patch on the water readily visible from the air in daylight for purposes of navigation or identification.  Generally, aluminum powder with stearic acid is used as the filling to form a slick.

Smoke generators are designed to emit smoke, sometimes colored, upon ignition of their filling.  Only one type of generator is discussed, since it is the only one intended to be dropped from aircraft in flight.

 
 

Navigation Flame Float Mk I (Obsolescent)

   

Overall length: 17 inches (Extended); 8 inches (Collapsed)
Body diameter: 3.7 inches
Filling: Calcium Phosphide
Filling weight: 2 pounds
Total weight: 3.2 ounces
Burning time: 5 minutes

Fuzing: Non; water initiated
  

Color and markings: Cylinder painted red with yellow label on lid.

  

Description: The float consists of a cylindrical tin-plate canister with a tin-plate lid, having a central aperture, soldered over the top of the canister, and a slotted brass sealing patch soldered over the aperture.  Soldered to the lid is an iron gauze tube, which extends axially nearly to the bottom of the canister, and is closed at its lower end.  The annular space outside the gauze tube is filled with granular calcium phosphide.  At its base the canister is closed by a cap, which fits over its outside.

The canister is surrounded by an outer fabric bag, which is considerably longer than the canister.  Secured by a double row of stitching inside the outer fabric bag and above the canister, is a second fabric bag, termed the inner fabric bag.  Two eyelets are located above the top of the canister in the walls of the inner and outer fabric bags at different levels.  The pull-off line passes through the aperture in the leather patch at the top of the inner fabric bag and through the neck of the outer fabric bag.  The aperture has a fairly snug fit on the line.

   
Functioning: When the flame float has been prepared for use by removing the brass sealing patch and has been dropped into the sea, water enters the canister through the aperture in its lid and passes through the eyelets.  The water enters the gauze tube, through which it penetrates into the calcium phosphide filling.  Phosphine is then evolved, inflating the inner fabric bag, and providing sufficient buoyancy to bring the flame float to the surface of the sea.  The gas escapes from the neck of the outer fabric bag, and takes fire spontaneously on contact with the air, producing a highly luminous flame.


Remarks: The flare may be dropped from any height and gives a reasonably steady and bright flame for about five minutes.  A flame continues for an additional 15 minutes, but it becomes increasingly feeble and intermittent.  If the sealing patch of the canister has been removed, the flame float must be dropped or removed to a safe place for disposal.

Navigational Flame Float Mk II, and No.4 Mk I, 
and Message Carrying Flame Float Mk I(Service)

Overall length: 23.4 inches
Body diameter: 5.9 inches
Filling: Calcium Phosphide
Filling weight: 1.8 pounds
Total weight: 11.8 pounds

Effective illumination: 6 minutes

Fuzing: Integral striker mechanism
  

Color and markings: Body, strut supports, strut, and protecting cap painted red,
tail cone painted yellow.

  

Description: The Flame Float Mk II consists of two main parts, a body and a container.  The body is a cylindrical casting, to one end of which three strut supports are riveted.  A cylindrical strut is riveted to the supports.  Secured to the fin by a securing wire is a punch to which is attached an instruction tag.  The body is thickened at the nose end, and has an attached conical nose of thin sheet steel.  A protecting cap is fitted over the nose, and a safety pin passes through holes in both the cap and nose.

The container consists of a sheet-metal cylinder, to one end of which is attached a sheet-metal tail cone.  The opposite end of the container is closed by a cap.  The cap is apertured and carried a correspondingly apertured spigot and a wire gauze socket on the side facing the tail cone.  Passing axially along the container is a central tube, one end of which is soldered to the narrow end of the tail cone, while the other end fits into the socket.  Near the tail end, the tube is closed by a sealing cup, projecting from which is a punch sleeve closed by a paper cap.  On the side opposite the spigot the cap carries a diaphragm, which retains a striker.  The striker is bored to receive the safety pin.

The lower part of the container is filled with granular calcium phosphide, which is held in position by a closing disc.  This material surrounds the slotted portion of the central tube.  Beyond the closing disc the annular space between the container and the central tube forms a sealed buoyancy chamber.


Functioning: Before the float is dropped, the punch is removed from the strut by cutting the securing wire, and the sealing cup on the punch sleeve is punctured with it.  After the sealing cup has been broken, the flame float must be dropped from the aircraft immediately. 

On dropping from an aircraft, impact with the water crushes the nose of the float and causes the striker to penetrate the sealing disc.  At the same time the securing wires holding the container to the body are broken, and the container and tail cone are forced away from the body.  The buoyancy chamber maintains the tail cone uppermost in the water.  Water enters the aperture in the cap, and passes through the gauze socket and the slots in the central tube into the calcium phosphide.  The phosphine generated on entry of the water passes upwards through the central tube, from which it emerges through the hole pierced by the punch through the sealing cup, and, on contact with the air, takes fire spontaneously.


Remarks: The inner body of the Navigation Flame Float No.4 Mk I is identical to the inner body of the Float Mk II.

The Message Carrying Flame Float Mk I is almost identical to the Navigational Flame Float Mk II in dimensions and construction.  The essential difference is that a message container is suspended in the buoyancy chamber by a fixing wire secured to a plug, which is screwed into a bush in the tail cone.  The plug is provided with a handle to facilitate its removal from the bush, and a washer on the plug insures a water-tight joint.  An arrow and the words, MESSAGE HERE, are painted on the tail cone to direct attention to the message.
 

Navigational Flame Float No.3 Mk I (Obsolescent) and No.3 Mk II (Service)
   

Overall length: 18.5 inches
Body diameter: 2.9 inches
Filling: Calcium magnesium phosphide

Total weight: 2.5 pounds

Effective illumination: 5 minutes

Fuzing: None; water initiated
  

Color and markings: Yellow overall

  

Description: The Flame Float No.3 Mk I has a cylindrical tinplate body, the after end of which has four attached tail fins.  The tail end of the body is closed by a tail cover having a central hole.  The neck of the tail cap is closed by a thin rupture disk to which is secured a small pillar having a ring passing through it.  The forward end of the body is closed by a cast-iron nose having a central water-inlet hole.  The nose is contained in a tin-plate cover, having a central hole covered by a tear-off seal to which is secured either a ring or an eyelet.  Inside the body is a perforated zinc central tube surrounded by a swansdown bag containing calcium magnesium phosphide.  Cotton wool is packed around the tail end of the bag, and a layer of glass wool is located between the bag and the iron wire gauze.  The charcoal is provided to absorb any slight traces of gas which may be given off while the flame float is in storage.  The tail end of the body comprises the buoyancy chamber of the flame float.


Functioning: Before dropping, the tear-off seal at the nose is removed.  When dropped, the tail rupture disc is broken and the float rises to the surface.  Water enters through the water-inlet hole in the nose, passes through the perforated zinc tube, and soaks through the flannel finger into the swansdown bag, where it reacts with the calcium magnesium phosphide to give off spontaneously inflammable phosphine.  The phosphine, so generated, escapes through the broken rupture disc and takes fire on contact with fire.


Remarks: Should either of the seals be broken while in storage, the damaged flame float must be removed to a dry place where the possibility of its catching afire is an acceptable risk pending final disposal.

The Float Mk II differs from the Mk I in that a rear seal and tear-off cord are substituted for the tail rupture assembly of the Mk I.  The long perforated tube of the Mk I is considerably shortened in the Mk II.

Marine Marker Mk I (Obsolescent)
  

Overall length: 26.8 inches
Body diameter: 5.8 inches
Filling: Aluminum and magnesium phosphides

Total weight: 16 pounds

Effective illumination: 2 hours

Fuzing: None; water initiated
  

Color and markings: Body and nose red.  Tail and tail cap yellow.

  

Description: The marker consists of a light metal body and tail, which are separated by a diaphragm.  The tail is closed by a metal plate, having a tail cap connected to the main outlet tube.  The forward end of the body is closed by a heavy metal plate into which are set two water-inlet valves.  A tube passes from the central valve, through the filling and spring-loaded pressure plate, and almost to the diaphragm.  The pilot tube extends aft from the off-centre valve to the pressure plate.  The pilot outlet tube then continues to a strainer attached to the diaphragm from which the main outlet tube issues.  The pressure plate retains the main filling in the forward part of the body.


Functioning: When the marker has been prepared for use and dropped into water, the water jacket fills and the scalloped disc in the main valve and the large disc in the pilot valve are forced against the ledges in the valves, thus preventing too great an ingress of water while it is submerged.  Some water, however, enters the main outlet tube, passes through the pressure plate, and reacts with the calcium phosphide.  This reaction evolves impure phosphine gas, which ignites spontaneously when the marker surfaces.  As it surfaces, the pressure against the valves is relaxed, and the springs return the discs against the circlips, thus permitting the ingress of water though the scallops in the disc to the bottom of the inlet tube and pilot tube.  The water entering the main valves passes through the inlet tube into the perforated tube, and after passing through the perforated diaphragm percolates through the flannel sheath and reacts with the main charge to give off pure phosphine, which is not spontaneously inflammable.  The cap over the free end of the perforated tube prevents the water from percolating through the part of the flannel sheath above the pressure plate.

The water entering the pilot valve percolates through the flannel disc and dissolves the potassium bisulphate and the sodium nitrite.  The chemicals interact and evolve gaseous oxides of nitrogen which mix with the phosphine in the strainer.  The mixed gases are spontaneously inflammable in air, and, passing through the main outlet tube, ignite immediately on reaching the air.  The flame thus produced continues to burn evenly for approximately two hours, during the whole of which time the gases remain spontaneously inflammable, so that even if the flame is put out by a wave, it lights up again as soon as contact with air is re-established.


Remarks: The flame is visible in daylight over a distance of at least three miles, and at night over a distance of about 20 miles.  White smoke is given off with the flame.  In damp atmosphere, after removal of the over-seals and press-caps, this marker evolves spontaneously inflammable phosphine, and for this reason should be prepared for use only just before it is to be launched.

   

Marine Marker Mk II (Service)

  

Overall length: 30 inches
Body diameter: 5.8 inches
Filling: Magnesium-aluminum phosphide

Total weight: 19 pounds

Burning time: 2 hours

Fuzing: None; water initiated
  

Color and markings: Body and nose transit cover painted red,
tail, tail cap, and tail transit cap painted yellow.

  

Description: The marker consists of a body with a steel nose at one end, having a central hole closed by a stopper which forms part of a thin bakelite disc secured to the nose by screws.  The disc is protected during transit and storage by a nose transit cover held in position by adhesive tape.  The tail constitutes a buoyancy chamber, and a main outlet tube extends between the diaphragm and a tail cap at the outer end of the tail.  The tail cap has a neck closed by a thin rupture disc, to which is secured a small pillar having a ring attached to it.  Two locating pieces, secured to the outside of the body, are provided to locate a suspension band in position if the marker is to be carried on a Light Series Bomb Carrier.


Functioning: When it is dropped into water, the bakelite disc is broken by impact with the water; the stopper falls away and the marker rises to float on the surface.  Water enters the central hole in the nose, and after passing through the gauze thimble, some of it soaks through the flannel washer, passes through the small hole in the valve body, and enters the brass tube after soaking through the flannel washer in the tube.  The remainder of the water passes through the water-inlet tube, percolates through the open-mesh metallic cylinder and its flannel sheath, and enters the body of the marker.  The brass cap prevents water from passing through the sheath and coming into direct contact with the calcium phosphide.  The water which enters through the nose reacts with the magnesium-aluminum phosphide and gives off pure phosphine, which is not spontaneously inflammable.  Some water, however, passes down the main outlet tube while the marker is submerged, and this water reacts with the calcium phosphide to produce phosphine which, in contact with the air, is spontaneously inflammable.  The supply of spontaneously inflammable gas lasts only about three minutes, and the flame is thereafter maintained by the phosphine evolved from the magnesium-aluminum phosphide mixing with the gaseous oxides of nitrogen given off by the interaction of the potassium bisulphate and the sodium nitrite, which are dissolved by some of the water which enters through the nose.

Marine Marker Mk III (Service)

Overall length: 36.8 inches
Body diameter: 6 inches
Filling: Magnesium-aluminum phosphide

Total weight: 21 pounds

Burning time: 2 hours

Fuzing: None; water initiated
  

Color and markings: Blue grey overall

  

Description: The outer casing of this marker consists of a body and a tail which are connected by a diaphragm.  A heavy nose is secured to the body.  The nose has a cavity to receive the time valve, and a central hole at the bottom of the cavity which is closed by a transit plug.  The valve is a clockwork device which permits the marker to remain in the water for a period up to six hours before it functions.  The period of delay is determined by setting the valve before the marker is released from the aircraft.  The main filling consists of magnesium-aluminum phosphide, and is packed round a gauze cylinder.  Inside the gauze cylinder is a quantity of fast calcium phosphide, which also extends over the top of the magnesium-aluminum phosphide.  The main filling is held in place by a thin steel plate having large holes covered by brass gauze, and a large spring anchored to a spring-supporting plate, which abuts against the diaphragm connecting the tail to the body of the weapon.  A layer of charcoal is provided beneath the steel plate to absorb any small quantities of phosphine gas generated by traces of moisture which may be in the body of the marking during filling, and a layer of glass wool beneath the charcoal which acts as a dust filter.  The tail constitutes a buoyancy chamber, and a main outlet tube extends between the diaphragm and a tail cap at the outer end of the tail.


Functioning: After entering the water, the marker rises to the surface and floats tail uppermost, water entering the nose cavity through the two small holes in the side of the nose.  At the expiration of the delay set on the time valve, the Welvic plug sealing the hole in the side of the time valve is opened and the water passes through the time valve and the central hole at the bottom of the nose cavity, into the water inlet valve in the nose.  Some of the water entering the water-inlet valve soaks through the flannel washer and passes through the small hole in the inlet valve into the brass tube to react with the filling in the brass tube.  The remaining water, after dissolving the soluble disc covering the nut, passes upwards through the water-inlet tube, percolates through the coarse-mesh cylinder, the flannel sheath, and the fine-mesh cylinder, and enters the body of the marker.  The brass cap prevents water from passing through that portion of the sheath which is above the fine-mesh cylinder.

The water passing through the fine-mesh cylinder, together with the small quantity which passes down the main outlet tube while the marker is submerged, reacts with the calcium phosphide in the gauze cylinder and covering the top of the main filling, to produce impure phosphine, which, in contact with air, is spontaneously inflammable.  This supply of gas lasts only for a few minutes, and is thereafter maintained by the pure phosphine evolved from the magnesium-aluminum phosphide mixing with the gaseous oxides of nitrogen given off by the interaction of the potassium bisulphate and the sodium nitrite, which are dissolved by the water entering the brass tube.


Remarks: When breaking the rupture disc, do not hold the head directly over the tail cap of the marker.  This avoids possibly injury to the eyes which might be caused should sufficient pressure be built up in the marker to force phosphide dust particles past the glass wool filter at the top of the main filling.

 

Next Time: Aircraft Pyrotechnics Part 2

Imperial Japanese Navy Explosives - Bombs (Part 7)

Imperial Japanese Navy Explosives

5kg Parachute Flare Model 2 Modification 1

 

Fuzes: Pull igniter

Overall Length: 25 and 1/8 inches

Diameter: 3 and 1/8 inches

Material of wall: Light sheet steel
  

Type of suspension: None

Suspension lug: Thrown by hand from plane

 

Type of filling: Illuminant

Weight of filling: 5 pounds 8 ounces

Total weight of flare: 10 pounds 3/4 ounce

Composition of illuminant:
-Barium nitrate: 55.5%
-Aluminum, powdered: 11%
-Magnesium, powdered: 18%
-Wax: 9.1%
 

Color and markings: Body is grey overall.  Two labels give description and instruction for use.
 

Construction: The flare case is cylindrical and of light sheet steel construction.  It contains an illuminating candle unit and a parachute, and is closed at both ends by metal caps.  The cap on the parachute end may be removed by pulling a tear strip.

The illuminating candle unit container is cylindrical in shape and is made of corrugated sheet tin.  A copper tube extends the length of the unit and the illuminant is cast around it.  A wooden plug is fitted into the top of the flare and is held there by a metal cap and several screws.

The fuze is inserted in a hole in the plug and fits down into the copper tube.  Four black powder impregnated strips are attached to the fuze and extend down the copper tube to the base of the illuminant.  Similar black powder strips are cast in the bottom of the flare.  A wooden ring in the base of the candle unit holds it away from the bottom of the flare containers.

The fuze used is of the pull igniter type.  A tin cylinder fits over the end of the fuze and extends up through the parachute to the end cap.  The pull cord attached to the catch on the fuze is led up through the tin cylinder to the end cap.

The parachute is made of silk and is attached to the candle unit by a length of wire rope.  The wire rope is spliced and the two ends are attached to two eyes fastened to the wooden plug in the end of the illuminant container.

Operation: The tear strip is pulled and the end cap removed.  Then the igniter cord is pulled and the flare is thrown from the plane.  The striker in the fuze hits the primer which ignites the powder train.  This burns slowly down to the black powder strings cast in the base of the illuminant, igniting the illuminant.  The expanding gases expel the candle unit and the parachute from the container.  The unit burns for approximately 1 minute and 30 seconds giving off a brilliant white flame.

 

 

 

Type 0 Parachute Flares Model 1 and Model 1 Modification 1
 

 
Fuzes: D-3(a), D-4(a)

Overall Length: 42 and 1/2 inches

Length of body: 39 and 1/2 inches

Diameter of body: 6 and 3/4 inches

Thickness of wall: 3/64 inches

Material of wall: Sheet Steel
 

Type of suspension: Horizontal

Suspension lug: Normal Navy suspension lug

Length of tail: 14 and 3/4 inches
Width of tail fins: 1 and 13/16 inches

Dimensions of tail struts: None

Material of tail: Sheet Steel
 

Type of filling: Illuminant (silver-grey in appearance)

Weight of filling: 66 pounds

Total weight of bomb:
-Model 1: 84 pounds
-Model 1 Modification 1: 88 pounds
 

Color and markings:
-Model 1: Grey overall with 1/4-inch red stripe just below the end piece
-Model 1 Modification 1: Grey overall with a 1/4-inch red stripe just above the end piece and a 1/2-inch white stripe around the body.
 

Construction: The flare consists of three main elements: (1) the flare case, (2) the illuminating candle unit, (3) the parachute.

1. The flare case consists of three sections: a nosepiece, body, and end cap.  The nosepiece is soldered securely to the body, and the hemi-spherical end cap is held in position by spot soldering in four places.  Four tail fins are welded to the after two-fifths of the body.  A steel ring 1 inch wide fits around the body at its junction with the tail cone.  It is attached to the fins and serves to brace them as well as to retard the velocity of the flare's free fall.  The nose is threaded to receive the fuze.

2.  The illuminant is contained in a cardboard canister which is covered by sheet brass 0.025 inch thick.  The after end is closed by a steel plate held by screws to the cylinder.  A 1/4-inch wire rope 65 inches long from which the candle unit is suspended is attached to this steel plate by means of a shackle.  The forward end of the container is open and fits against a wooden block in the nosepiece.  The illuminant at the opened end contains in its center an ignition charge 3 inches in diameter and 1/4-inch thick.

Length of illuminant container: 26 inches
Length of illuminant: 24 and 1/2 inches
Diameter of illuminant: 5 and 1/2 inches

3.  Model 1: A single silk parachute is housed in the after end of the body.  It is surrounded by a layer of cardboard to insure smooth ejection.
 
Model 1 Modification 1: A small guide parachute and a larger parachute are housed in the after end of the body.  They are surrounded by a layer of cardboard to insure smooth injection.
 

Operation: Shortly after being released from the plane the aerial burst fuze operates.  The resultant flash from the magazine ignites the ignition charge which in turn ignites the illuminant.  The expanding gases force the end cap off and eject the parachute and illuminating candle unit.  The flare sheds a bright white light and burns for 3 minutes and 40 seconds.

 

 

 

Type 0 Parachute Flares Model 2 and Model 3 Modification 1

   
Fuzes: D-3(a), D-4(a)

Model 2

Overall Length: 38 and 1/2 inches

Length of body: 35 and 1/2 inches

Diameter of body: 6 and 3/4 inches

Thickness of wall: 3/64 inches

Material of wall: Sheet Steel

Model 3 Modification 1

Overall Length: 42 and 1/2 inches

Length of body: 39 and 1/2 inches

Diameter of body: 6 and 3/4 inches

Thickness of wall: 3/64 inches

Material of wall: Sheet Steel

  
 

Type of suspension: Horizontal

Suspension lug: Normal Navy suspension lug

Model 2
Length of tail: 13 and 1/2 inches

 

Model 3 Modification 1

Length of tail: 15 inches

 

 

Dimensions of tail struts: None

Material of tail: Sheet Steel
 

Type of filling: Illuminant

Weight of filling: 66 pounds

Total weight of bomb:
-Model 2: 84 pounds
-Model 3 Modification 1: 88 pounds
 

Color and markings:
-Model 2: Grey overall with 1/4-inch red stripe just below the end piece
-Model 3 Modification 1: Grey overall with a black stripe around the nose and a 1/4-inch red stripe above the end piece.
 

Construction: The flare consists of three main elements: (1) the flare case, (2) the illuminating candle unit, (3) the parachute.

1. The flare case consists of three sections: a nosepiece, body, and end cap. The nosepiece is soldered securely to the body, and the hemi-spherical end cap is held in position by spot soldering in four places.  Four tail fins are welded to the after two-fifths of the body. A steel ring 1 inch wide fits around the body at its junction with the tail cone. It is attached to the fins and serves to brace them as well as to retard the velocity of the flare's free fall.   The nose is threaded to receive the fuze.

2. The illuminant is contained in a cardboard canister which is covered by sheet brass 0.025 inch thick. The after end is closed by a steel plate held by screws to the cylinder. A 1/4-inch wire rope 65 inches long from which the candle unit is suspended is attached to this steel plate by means of a shackle. The forward end of the container is open and fits against a wooden block in the nosepiece. The illuminant at the opened end contains in its center an ignition charge 3 inches in diameter and 1/4-inch thick.

Length of illuminant container: 26 inches
Length of illuminant: 24 and 1/2 inches
Diameter of illuminant: 5 and 1/2 inches

3. Model 2: A single silk parachute is housed in the after end of the body. It is surrounded by a layer of cardboard to insure smooth ejection.

Model 3 Modification 1: A small guide parachute and a larger parachute are housed in the after end of the body. They are surrounded by a layer of cardboard to insure smooth injection.

Operation: Shortly after being released from the plane the aerial burst fuze operates. The resultant flash from the magazine ignites the ignition charge which in turn ignites the illuminant. The expanding gases force the end cap off and eject the parachute and illuminating candle unit. The flare sheds a bright white light and burns for 3 minutes and 40 seconds.

Experimental Model 11 Parachute Flares

 

Fuzes: D-3(a), D-4(a)

Model 11 Conical

Overall Length: 45 inches

Length of body: 43 and 1/2 inches

Diameter of body: 9 and 1/4 inches

Thickness of wall: 3/64 inches

Material of wall: Sheet Steel

Model 11 Ogival

Overall Length: 46 and 1/2 inches

Length of body: 43 and 1/2 inches

Diameter of body: 9 and 1/4 inches

Thickness of wall: 3/64 inches

Material of wall: Sheet Steel

 

Type of suspension: Horizontal

Suspension lug: Normal Navy suspension lug

Length of tail fins: 13 and 3/4 inches

 

Dimensions of tail struts: None

Material of tail: Sheet Steel

Type of filling: Illuminant

Weight of filling: 68 pounds

Total weight of bomb:
-Model 11 Conical: 106 pounds
-Model 11 Ogival: 110 pounds
 

Color and markings: Grey overall with 1/4-inch red stripe above the end piece
 

Construction: The flare consists of three main elements: (1) the flare case, (2) the illuminating candle unit, (3) the parachute.

1. The flare case consists of three sections: a nosepiece, body, and end cap. The nosepiece is soldered securely to the body, and the hemi-spherical end cap is held in position by spot soldering in four places. Four tail fins are welded to the after two-fifths of the body. A steel ring 1 inch wide fits around the body at its junction with the tail cone. It is attached to the fins and serves to brace them as well as to retard the velocity of the flare's free fall. The nose is threaded to receive the fuze.

2. The illuminant is contained in a cardboard canister which is covered by sheet brass 0.025 inch thick. The after end is closed by a steel plate held by screws to the cylinder. A 1/4-inch wire rope 65 inches long from which the candle unit is suspended is attached to this steel plate by means of a shackle. The forward end of the container is open and fits against a wooden block in the nosepiece. The illuminant at the opened end contains in its center an ignition charge 3 inches in diameter and 1/4-inch thick.

Length of illuminant container: 25 and 3/4 inches
Length of illuminant: 23 and 3/4 inches
Diameter of illuminant: 7 and 3/4 inches

3.  A small guide parachute and a larger parachute are housed in the after end of the body. They are surrounded by a layer of cardboard to insure smooth injection.

Operation: Shortly after being released from the plane the aerial burst fuze operates. The resultant flash from the magazine ignites the ignition charge which in turn ignites the illuminant. The expanding gases force the end cap off and eject the parachute and illuminating candle unit. The flare sheds a bright white light and burns for 4 minutes and 40 seconds.

Type 94 and Experimental Type Modification 1 Float Lights

 

Fuzes: None

Type 94

Overall Length: 11 and 7/16 inches

Length of body: 11 and 7/16 inches

Diameter of body: 2 and 13/16 inches

Thickness of wall: 3/64 inches

Material of wall: Tin Plate

Experimental type, Modification 1

Overall Length: 21 and 3/4 inches

Length of body: 21 and 3/4 inches

Diameter of body: 4 and 3/4 inches

Thickness of wall: 3/64 inches

Material of wall: Tin Plate

Type of suspension: None

Suspension lug: None

Type 94

Length of tail: 2 and 3/4 inches

Width of tail: 3 inches
Width of tail fins: 1 and 3/4 inches
Dimensions of tail struts: None
Material of tail: Tin Plate

Experimental type, Modification 1

Length of tail: 7 inches

Width of tail: 5 inches
Width of tail fins: 2 and 3/8 inches 

Dimensions of tail struts: 5 inches x 3/8 inch x 1/32 inch

Material of tail: Tin Plate
  

Type of filling: Calcium carbide and Calcium phosphide

Total weight of bomb:
-Type 94: 2.2 pounds
-Experimental type, Modification 1: 6.6 pounds

Charge/weight ratio:
-Type 94: 23%
-Experimental type, Modification 1: 33%
  

Color and markings:
-Type 94: Grey with red pull rings.  One paper label
-Experimental type, Modification 1: Chrome yellow.  Red pull rings.  Two paper labels.
 

Construction of body:  In both types the body is constructed of tin plate rolled into a cylinder with soldered lapped joints.  The hemispherical nosepiece and conical tail piece are soldered to the body.  The nosepiece houses a lead weight. 
  
The calcium carbide is contained in the forward part of the body, the calcium phosphide in the after part.  Two metal tear strips cover water inlet holes in the nose and tail.
  

Construction of tail: Four steel fins are soldered to the body and tail cone.  There are no struts on the Type 94.  The fins on the experimental type are braced by a single set of box-type struts.

Operation: The tear strips are removed before dropping.  On impact with the water, the water enters the holes formerly covered by the tear strips.  Water reacts with calcium phosphide to generate phosphine and calcium carbide to generate acetylene gas. 

On contact with the air phosphine ignites spontaneously and the resultant flame is fed by the acetylene which acts as the main source of fuel.

Type 94 Model 2 and Type 0 Model 1 Float Lights

 

Fuzes: None

Type 94 Model 2

Overall Length: 10 inches

Length of body: 10 inches

Diameter of body: 2 and 13/32 inches

Thickness of wall: 3/64 inches

Material of wall: Tin Plate

Type 0 Model 1

Overall Length: 13 and 13/16 inches

Length of body: 13 and 13/16 inches

Diameter of body: 2 and 7/8 inches

Thickness of wall: 3/64 inches

Material of wall: Tin Plate

Type of suspension: None

Suspension lug: None

Type 94 Model 2

Length of tail: 3 and 1/4 inches

Width of tail fins: 1 inches
Dimensions of tail struts: None
Material of tail: Tin Plate

Type 0 Model 1

Length of tail: 4 and 1/8 inches

Width of tail fins: 1 and 5/8 inches

Dimensions of tail struts: 3 and 1/8 inches x 1/4 inch x 1/32 inch

Material of tail: Tin Plate

Type of filling: Calcium carbide and Calcium phosphide
 

Color and markings: Grey overall with two labels posted on body.
 

Construction of body: In both types the body is constructed of tin plate rolled into a cylinder with soldered lapped joints. The ogival nosepiece and conical tail piece are soldered to the body. The nosepiece houses a lead weight.

The calcium carbide is contained in the forward part of the body, the calcium phosphide in the after part. Two metal tear strips cover water inlet holes in the nose and tail.
 

Construction of tail:
-Type 94 Model 2: Three tail fins are soldered to the tail cone.  There are no struts.

-Type 0 Model 1: Four tail fins are soldered to the body and tail cone and are braced by a single set of box-type struts.

Operation: The tear strips are removed before dropping. On impact with the water, the water enters the holes formerly covered by the tear strips. Water reacts with calcium phosphide to generate phosphine and calcium carbide to generate acetylene gas.

On contact with the air phosphine ignites spontaneously and the resultant flame is fed by the acetylene which acts as the main source of fuel.

Remarks: The Type 0 Model 1 float light has a deflector on the exterior of the nosepiece which prevents it from penetrating too deeply into the water.

2kg Smoke Float

  

 

Fuze: Pull Igniter

Overall Length: 18 and 1/8 inches

Diameter of body: 4 and 3/4 inches

Type of suspension: Thrown by hand

Total weight: 4 and 3/4 pounds

Color and markings: White except for yellow nose

Description: A cast-brass nosepiece weighted with lead is soldered to a conical body of 22 gage sheet metal.  A smoke candle unit screws into the nose.  An emission tube, supported by three metal disks, passes lengthwise through the center of the body and has a cork plug in the tail end.  Three rounded tail fins are soldered around the after end of the body.

The smoke candle unit consists of a casing of light alloy containing a smoke-producing composition.  A quick match wich and a length of safety fuse connects the candle with the igniter.  The igniter casing contains a release pin, a spring-loaded striker and primer pressed into a plug which screws into the end of the casing.

Operation: The safety pin is removed and the release pin is withdrawn by pulling on the pull ring.  The striker spring is compressed until the release pin is free of the casing and then the striker is released.  It strikes the primer thus igniting the safety fuse and quick match wick which ignites the smoke composition (after a short delay) which produces a yellow smoke.

Remarks: This smoke float will also be found with a black nose and white body.  When so painted, it contains a black smoke unit.



43kg Smoke Float

 

Fuze: D-3(a) (with vane cups)

Overall Length: 51 inches

Length of body: 35 and 1/2 inches

Diameter of body: 11 and 1/4 inches

Thickness of wall: 1/32 inch

Material of wall: Sheet steel
 

Type of suspension: Horizontal

Suspension lug: Normal Navy suspension lug
 

Length of tail: 15 inches

Width of tail: 13 and 1/2 inches
Width of tail fins: 2 and 3/4 inches

Dimensions of tail struts: None

Material of tail: Sheet Steel

Type of filling: Smoke composition
Weight of filling: 42 pounds (including container)
Total weight of bomb: 94 pounds
 

Color and markings: Gray overall with a 1/4-inch red stripe forward of the end cap.

 

Description: The float consists of five sections: a weighted nose, a conical body, a boat-tailed attachment, an after piece and an end cap.  All parts are soldered solidly together with the exception of the end cap which is held on by four spot solders.  Four fins are soldered to the after piece and boat-tailed attachment.  The fuze pocket is located in the side of the after piece and has an extended opening.

The smoke composition is contained in a tin cylinder running from the nosepiece to a steel ring in the boat-tailed attachment.  A pull igniter, delay train, and quickmatch composition are contained within the smoke unit.

The parachute of light weight white silk is packed compactly in the after piece.  The parachute is secured to a 1/4-inch wire rope which is attached to a shackle on a wooden block.  At the junction of the parachute shrouds and wire rope is a chock absorber 3/8-inch bungee rubber strands.  On the opposite side of the block are two 1/4-inch wire ropes which lead through a second wooden block to a steel ring at the after end of the boat-tailed attachment.

Lashed securely to one of the 1/4-inch cables is a 1/16-inch cable leading to a pull igniter in the smoke container.  A second 1/16-inch cable leads from the shackle on the after wooden block to a small wooden disk contained in the second block.  Around this is a black powder ejection charge.  A third 1/16-inch cable leads from the shackle to a contact on the body at the top of the container.

Operation: When the aerial burst fuze functions, the ejection charge is ignited.  The end cap is torn off and the parachute ejected.  As the parachute is blown out, the pull igniter is actuated and the delay train initiated.

The parachute checks the fall of the flare sufficiently to prevent smashing of the case on impact with the water.  The smoke composition burns from 5 to 8 minutes giving off a grey-black smoke that is heavier than air.

Next Time: IJN Markers, a "Window" bomb, and the Baka Bomb