Monday, 16 April 2018

American Projectiles and Explosives - Ground Pyrotechnics (Part 3)

American Projectiles and Explosives

Ground Pyrotechnics


Parachute Trip Flare M48

Diameter of flare tube: 2.5 inches
Height of trajectory: 300-500 feet
Burning time: 20 seconds
Intensity: 100,000 candlepower
Effective Illumination: Circle of 800 yards radius

Color: White to Yellowish

Use: The flare is used to give warning of enemy marauders or infiltrating hostile troops; also, for illumination or signaling.

Description: The flare consists of a 1/4-inch pipe and a steel tube approximately 2.5 inches in inside diameter, which are attached to a base plate that contains a 75-grain propelling charge.  The steel tube contains a delay fuse, an expelling charge, a candle, and a parachute assembly.  The 0.25-inch pipe and the firing mechanism are joined by a coupling, and the pipe is threaded to the base plate.  The firing train is composed of a primer, an igniter, and a relay charge.  The firing mechanism contains the pressure cap, pull ring and pin, safety screw, safety cotter pin, and spring-loaded firing pin.

Operation: A 20- to 30-pound pressure on the pressure cap or a tension of four to six pounds on the pull pin releases the firing pin and fires the primer.  The primer initiates the igniter, which, in turn, starts the relay charge.  The relay charge sets off the propelling charge, which projects the illuminating shell through the large steel tube to a height of 300 to 500 feet.  The propelling charge ignites a three-second delay fuse in the shell.  The delay fuze ignites an expelling charge which expels a parachute-supported candle from the shell.

Trip Flare M49

Length: 3.8 inches
Diameter: 2.5 inches
Burning time: 1 minute
Intensity: 40,000 candlepower

Color: White to Yellowish

Use: The Trip Flare M49 has the same uses as the Parachute Trip Flare M48

Description: The flare has a grenade-shaped cylindrical body, with a nose fuze that protrudes 0.875-inch from the head end.  A mounting bracket and a spring-loaded trigger mechanism are mounted on a metal base cap.  The upper arm of the trigger is attached to a trip wire, and the lower arm of the trigger restrains the safety lever after the removal of the safety pin.

Operation: A pull on the trip wire rotates the upper trigger arm away from the fuze lever.  If the trip wire is cut, the upper trigger arm, which is restraining the fuze lever, rotates away from the fuze lever but in an opposite direction from above.  A grenade-type fuze is used, but is has no delay element.  The fuze ignites the flare simultaneously.

Trip Wire Flare Mk 1 Mod 0

Length of tube: 5.5 inches
Diameter of tube: 2.5 inches
Weight: 3.5 pounds
Burning time: 65 seconds
Candlepower: 100,000
Effective illumination: Area 500 feet in diameter

Use: The purpose of the flare is to reveal the approach of enemy troops.

Description: The flare case is a steel tube approximately 5.5 inches long and 2.5 inches in diameter.  Fixed to one end is a pull-type, spring-actuated firing mechanism to which the trip wire is attached.  Enclosed in the tube are the primer, black-powder charge, impregnated muslin disc, and pyrotechnic composition.  Two 40-foot lengths of wire are available, making it possible to have two trip wires running in opposite directions.  A web belt secures the flare to a tree.

Operation: A tug of three pounds or more on the trip wire draws the plunger and firing pin away from the primer and compresses a spring which surrounds the firing pin.  As the plunger is pulled away from the firing mechanism, its notched end disengages from that of the firing pin, which is then forced against the primer by the compressed firing-pin spring.  The primer ignites 0.3 grams of black powder.  The black powder ignites the impregnated muslin disc, and in turn the pyrotechnic composition.  The resultant gas pressure blows out the closure disc from the head, and the flame from the burning candle illuminates the surrounding area.  White smoke given off by the flare does no interfere with the effectiveness of the illumination.

Remarks: To prevent self illumination, the flare should be mounted about 125 yards before friendly positions.  While mounting the flare, personnel should wear steel helmets, and heads should be kept below and away from the top of the flare.

Ground Flare M81-M83

No picture available

Length (w/o spike): 7.75 inches
Diameter: 1.75 inches
Weight: 0.88 pounds
Burning time: 2 minutes

Color and Intensity:
-M81: Red - 20,000 candlepower
-M82: Yellow - 25,000 candlepower
-M83: Green - 35,000 candlepower

Use: The flare indicates, to cooperating air elements, a line of position or direction.  It is also used for troop-recognition purposes.

Description: The flare consists of a paper cylinder containing a pyrotechnic composition.  It has a wooden base block with a 20-penny spike through it, and a match head covered by a removable metal cap, under which lies a wooden disc.  A plastic film seals the metal cup to the flare body.  The outer head of the wooden disc has the scratching surface required to ignite the match composition.

Operation: The flare is stuck in the ground with the spike as a support.  The plastic seal is pulled off and the wooden disc scratched against the match composition, which ignites the flare.

Remarks: These ground flares are not procured by the Navy at present.

Target Rocket Flare Mk 1 Mod 0

Weight: 3 pounds

Use: The Target Rocket Flare Mk 1 Mod 0 is used with the 3.25-inch Rocket Targets Mk 10 and Mk 11.

Description: A pyrotechnic candle, secured into a wooden body, is housed in a steel tube.  An electric squib is located over the starter composition of the candle.  A steel cup shields the ignition end of the flare, and squib leads are coiled inside the nose cap.

Operation: Tear off the adhesive strip and remove the cover.  Place the flare over the nose of the rocket, and uncoil the squib leads.  Fasten the alligator clips to the cotter pins of the leads, and fire.

Airport Flare M13 (Obsolete)

No picture available

  Length: 23.1 inches
Diameter: 1.75 inches
Intensity: 40,000 candlepower
Burning time: 3 minutes

Use: Airport Flare M13 is used to provide illumination for airplane landing at emergency fields, and to illuminate targets and objectives.  A further use is to prevent infiltration or surprise by enemy troops.

Description: The flare consists of a cylinder; the top cover sealed with a strip of adhesive tape, and a seven-inch hollow chip-board tube mounted to one end of the cylinder.

Operation: Remove the adhesive tape and slip the hollow tube over a rod stuck in the ground.  Pull on the lanyard attached to the ignition wire to fire the flare.

Remarks: This flare is not procured by the Navy.

Airport Flare M76

No picture available

  Length: 32 inches
Diameter: 6 inches
Intensity: 800,000 candlepower
Burning time: 6.5 minutes

Use: Airport Flare M76 is used to indicate the end of a runway in a fog.

Description: This flare consists of a cylinder containing a candle similar to, but larger than, the candle of the Flare AN-M26.  The cylinder is fitted with a socket base arrangement into which four channel-shaped legs may be inserted to hold the flare upright on the runway.

Operation: The flare may be initiated by the use of the electric squib or by pull on the release fork which allows the spring-loaded firing pin to strike the primer.  The primer acts directly to ignite the first fire composition.

Remarks: Airport Flare M76 is not procured by the Navy.

High-Altitude Parachute Mortar-Fired Flare Mk 20 Mod 0

No picture available

  Length: 10.75 inches
Diameter: 2.5 inches
Weight: 5 pounds
Height of trajectory: 1,000 feet
Intensity: 85,000 candlepower
Color: White
Burning time: 60 seconds
Rate of fall after ignition: 16 feet/second

Use: This high-altitude flare is used to illuminate seaplane landing areas at night, and to illuminate an island base when low ceilings do not permit proper visibility from normal flying levels. 

Flare: The flare consists of a cylindrical steel tube body with a copper cup welded to the closed tube body with a copper cup welded to the closed end of the tube.   The body contains an expelling charge, a pyrotechnic candle, and a silk parachute.  The copper cup contains a fuse assembly, a propelling charge, 25 grams of a combination smokeless powder and black powder, and a standard shotgun primer.

Mortar: The mortar consists of a steel tube 36 inches long and 2.8 inches in diameter.  The tube is screwed into a steel base plate 0.75 inches thick and 12 inches square.  The base plate is provided with a central stud into which is pressed a hardened steel firing pin.

Operation: Remove the closing cap from the end of the mortar.  Attach a 30-foot lanyard to the brass release pin and insert the pin in the two holes drilled transversely about six inches from the end of the mortar.  Insert the flare into the mortar so that it rests on the release pin, with the copper end down.  Fire the flare by pulling the lanyard, thus removing the release pin.  The flare falls to the bottom of the mortar, firing the primer.  The primer sets off the propelling charge and ignites the delay fuse.  the expanding gases force the copper cup away from the flare and fill the bore of the mortar.  The flare is propelled 1,000 feet into the air, at which time the delay fuse ignites the expelling charge.  The pyrotechnic candle and parachute are expelled, the expelling charge igniting the candle.

Remarks: A suitable barrier should be erected to shield personnel firing the flare.  In case of a misfire, wait at least three minutes before disassembling the mortar.  Clean mortar tube after firing.

Next Time: Shipboard Pyrotechnics

Monday, 9 April 2018

American Projectiles and Explosives - Ground Pyrotechnics (Part 2)

American Projectiles and Explosives

Ground Pyrotechnics

Launcher Type M17A1 - M22A1; M51A1; M52A1; and M17A1B2 - M22A1B2

Length: 10.5 inches
Diameter: 1.6 inches
Delay: 6 seconds
Height of trajectory: 600 feet

Description: The signal is assembled in a cylindrical case and equipped with a finned tail assembly for stabilization purposes.  It is similar to the projector type, but modified to be fired from a service rifle or carbine.  This type has a hollow stem, which is closed by a cork plug and a wheel-shaped fin.  The "A1B2" series is the same as the "A1" series, except that the former indicates steel construction.  Special cartridges are used to ignite the propelling charge.  Embossed letters on the closing cap indicate color and type of star(s).

Operation: Remove the cork plug from the tail and place the signal on a rifle launcher.  Place the butt of the rifle on the ground as far away as practicable.   When the rifle is fired, the cartridge fires the primer, which in turn ignites the propelling charge.  The signal travels approximately 100 feet and then reverses itself and reaches an altitude of approximately 600 feet.

High-Bursting Range Signal M27A1B1

No picture available

Length: 8.37 inches
Diameter: 1.5 inches
Weight: 9.25 ounces
Height of trajectory: 700 feet

This signal has the standard tube and fin assembly as the launcher types.  It is used in training maneuvers to simulate the air burst of an artillery shell.  It produces a flash and puff of smoke, and a noise audible for at least 2,000 yards.

Flash and Sound Signal M74

No picture available

General: The Flash and Sound Signal M74 is designed for simulation of air burst of artillery fire in training troops.  It is fired from the Hand Projector M9 or the Pyrotechnic Pistol AN-M8

Description: The signal consists of an outer case, an expelling charge, and an inner cylindrical case containing the delay fuze and bursting charge.  The outer case resembles those of the aircraft double-star type.  A percussion primer in the base of the outer case extends into the expelling charge.  The expelling charge sets off the delay fuze.

Operation: When fired, the primer ignites the expelling charge.  This ignites the delay fuze and propels the inner case out of the outer case.  After a delay of about two and a half seconds, the fuze ignites the burster charge which, in exploding, produces a bright flash and a loud noise.

Remarks: With the pistol or projector at 45 degree elevation, the signal will reach a height of about 100 feet for its burst.  Helmets should be worn by exposed personnel.

Smoke Signals M62, M64, M65, and M66

Length: 10.15 inches
Diameter: 1.88 inches
Bursting altitude: 600 feet

-M62: Red
-M64: Yellow
-M65: Green
-M66: Violet

Use: These signals are employed by artillery observes to signal or lay in a line of fire.

Description and Operation: The signal is launched in the same manner as the M17A1 series.  The fuze delay ignites an expelling charge, which expels and ignites the six smoke pellets at an altitude of 600 feet.  The pellets burn and fall, leaving a colored smoke trail.

Pistol Rocket Signals Mk1 Mod 2 and Mk 2 Mod 1

  Length: 14 inches
Diameter: 1.5 inches
Burning time: 21 seconds
Weight: 1 pound

Use: These signals are for identification on other signalling between ground troops.

Description: Similar in construction to the submarine signal, Pistol Rocket Signal Mk 1 Comet, the Pistol Rocket Signal Mk 1 Mod 2 produces a chameleon signal consisting of three parachute-borne stars which burn successively in three colors.  Each star burns for approximately seven seconds before the next color ignites.  The Pistol Rocket Signal Mk 2 Mod 1 is a smoke signal, a parachute-borne smoke candle, but is generally the same construction as the Mk 1 Mod 2.

Operation: The signals are fired from the Submarine Rocket Pistol Mk 1 Mod 0 or the Pyrotechnic Pistol AN-M8.  The primer ignites the one-gram auxiliary expelling charge, which projects the upper section of the signal to a height of 30 feet, where the rocket powder ignites, sending the signal on up to 650 feet.  There the pyrotechnic element, chameleon or smoke, ignites.  As the signal leaves the projector or pistol, the spring-loaded vanes fold out into place, stabilizing the flight of the signal.

Illuminating Hand Grenade Mk 1

  Length: 4.3 inches
Diameter: 2.1 inches
Weight: 9.2 pounds
Intensity: 60,000 candlepower
Delay: 7 seconds
Burning time: 25 seconds

Description: The grenade consists of two metal shells pressed together and sealed.  The upper shell contains a Bouchon igniter and a delay fuse.  The bottom shell contains the illuminant composition, first fire charge, ignition charge, quick match, and disc.

Operation: Pull the release pin and throw the grenade.  When the lever is released, the firing pin is freed to fire the primer.  The primer ignites the delay fuse, which burns for seven seconds and then ignites the ignition charge.  The ignition charge sets off the first fire composition, which in turn ignites the illuminant composition.  The gases from the ignition charge and first fire force the two shells apart, thus leaving the illuminant composition of the bottom shell free for burning.

Next Time: Ground Pyrotechnics (Part 3)

Monday, 2 April 2018

American Projectiles and Explosives - Smoke Streamer and Photoflash Bombs, and Ground Pyrotechnics (Part 1)

American Projectiles and Explosives

Aircraft Pyrotechnics

Smoke Streamer


Overall length: 47.5 inches
Body length: 40.5 inches
Body diameter: 8 inches
Wall thickness: 0.06 inches
Tail length: 11.5 inches
Tail width: 10.75 inches

Filling: 8 Modified Smoke Grenades M18
Total weight: 100 pounds

Fuzing: The Fuze M143 consists of a fuze body support mounting four bouchon grenade-type fuzes and an arming washer, and is threaded to fit the fuze adapter of the tube train.  The arming washer is 2.5 inches in diameter and has four arms 0.75 inches wide and one inch long.  The arming wire holds the arming washer over the bouchon levers until it is withdrawn.

Construction: The bomb body consists of a sheet-steel case with a filling plug in the base.  The four tail vanes are welded to the truncated cone with box-type interior struts.  The complete body assembly consists of this Practice-Bomb Case M38A2, a train tube, a grenade train, a closing plug, and a fuze.  The train tube is a seamless steel tubing three inches in diameter and 40 inches long, with a fuze adapter brazed to the after end.  Eight modified Grenades M18 filled with fast-burning mixture are inserted into the tube to form the grenade train.  Each grenade is modified by cutting a center hole in its base, and the bouchon fuze is omitted. 
The top of each grenade is coated with a starter compound which acts as the igniter for the adjacent grenade.  Four strands of quick match are knotted and inserted in the center hole of the top grenade in such a manner as to leave the knot and loose ends at the top to receive the fuze flash.  The eight grenades are held apart by spring steel separators.  A threaded closing plug seals the tube and protects the grenade train from moisture.  This plus must be removed just prior to use.  the bomb is brought up to the weight of approximately 98 pounds by filling the balance of the internal space with sand.

Operation: When the arming wire is pulled, the bouchon springs throw off the arming washer and handles, allowing the bouchons to fire.  This action ignites the quick match in the center hole of the top grenade, which in turn is ignited, and the flash is simultaneously transmitted to all the grenades.

Remarks: The colored streamer smoke bomb is used as a visual signal to be dropped by the lead plane of a bomber formation when the target has been determined.  Smoke emission begins approximately one second after release from the plane and continues for approximately 7,000 to 10,000 feet.

Photoflash Bombs


Overall length: 25.4 inches
Diameter: 4.25 inches
Weight: 10.6 pounds
Weight of flash powder: 7.75 pounds

Fixed delay: 15 seconds
Duration of flash: 0.2 seconds
Intensity of flash: 150,000,000 candlepower
Release altitude: 4,000 to 7,000 feet

Use: This bomb is used to provide light of high intensity and short duration for night photography from low altitudes.

Description: The bomb case is made of cardboard closed with metal ends, one of which is marked "Front" to insure proper loading in the rack.  This end contains the hang-wire assembly just before the Fuze Assembly M23A1.  The fuze assembly is made up of the friction wires attached to the hang wire, match composition, quick match, delay element, upper and lower rings, and base ignition charge immediately adjacent to the flashlight powder charge.  The hang wire is attached to the arming-wire retainer.

Operation: When the bomb is released, the hang wire remains attached to the arming-wire retainer.  As the bomb drops, the hang wire pulls the friction wires through the match composition of the fuze.  The hang wire also pulls out the hang-wire container, allowing both the hang wire container and the bomb to fall free.  The flame from the match composition ignites a piece of quick match, which in turn ignites a delay element.  After 15 seconds, the delay element ignites the base charge of the fuze, which sets off the flashlight powder charge.  The flash lasts a fifth of a second.


Overall length: 48.4 inches
Diameter: 8 inches
Weight: 51.9 pounds
Weight of flash powder: 25 pounds

Burning time: 0.2 seconds
Peak intensity: 500,000,000 candlepower

Fuzing: M111A2, AN-M146

Use: The Photoflash Bomb An-M46 was developed so that planes engaged in night photography reconnaissance need not be limited to low altitudes.
Description: In appearance it resembles a conventional light-case bomb.  Uses a Fuze M111A2 in the nose, but it is issued unfuzed.  It also has two suspension bands for rack and shackle suspension.

Operation: When the bomb is dropped, the arming wire is pulled, starting the mechanical time fuze.  When the time set on the fuze has elapsed, the flashlight powder is ignited by the fuze booster.

Remarks: Because of the brilliance of the flash, it is detrimental to the vision to watch the explosion of photoflash bombs.  Extreme care should be exercised in handling these bombs, because the charge is very sensitive to friction, shock, and temperature.  These bombs should not be jettisoned over friendly territory, as they may function on impact.

Ground Pyrotechnics

One-inch Salute Mk 1 Mod 0

Length: 1.75 inches
Diameter: 0.75 inches

Use: This salute is used by the Marine construction battalions and amphibious training commands to simulate battle sounds of loud report and bright flash.

Description: Essentially a commercial-type firecracker, this salute is a spirally-wound paper tube closed at both ends with paper cups.  It uses the regular firecracker filling and fuse.

Firecracker Mk 2 Mod 0

General: This firecracker is used as a practice charge for booby traps and firing devices.  It produces a loud report, bright flash, and smoke.  It is designed to reduce the hazard of flying particles attendant upon use of a standard potassium perchlorate firecracker.  It is classified as fireworks, since it contains no high explosive.  Although coated with a waterproofing material, it should be stored in a dry place.

Installation: The coupling base of any standard firing device is pushed through the wax-filled hole in the hollowed end of the firecracker and rotated clockwise until at least two threads of the coupling base are inside the hollowed end.

Signal Light Mk 2

Burning time: 7
Candlepower: 300

Burning time: 6
Candlepower: 250

Burning time: 5
Candlepower: 600

Use: Signal Light Mk 2 is used primarily as a distress signal.

Description: The cartridge, sometimes called the Very signal, is similar in appearance to a 10-gauge shotgun shell.  The star charge is a tightly-packed cylinder of pyrotechnic material reinforced with wire and wrapped with quick match.  The propelling charge is composed of about 25 grains of black powder separated from the star charge by a hard felt pad.

Identification of the three types

Red Star: Paper wrapping is red; closing wad is corrugated

White Star: Paper wrapping is white; closing wad has a small cone in the center.

Green Star: Paper wrapping is green; closing wad is smooth.

Operation: The Signal Pistol Mk 5 may be used, as well as the Hand Projector Mk 3 or Mk 4.

The primer ignites the propelling charge, expelling the star out of the projector and igniting the quick match, which ignites the star as it leaves the barrel and burns as it rises to a height of about 200 feet.

Projector Type M17 - M22 Series (Obsolete)

Length w/o tail: 6 inches
Diameter: 1.6 inches
Delay: 6 seconds
Height of trajectory: 600 feet

Description: The signal is assembled in a cylindrical case, and equipped with a finned tail assembly for stabilization purposes.  The primer is located int he head of the signal, and the propelling charge is contained in a small cavity under the head.  The end opposite the primer is closed by a press-fit cap to which the tail assembly is attached.  The signal has a solid tail stem and an X-shaped fin.  Embossed letters on the fin indicate the color and type of star(s).

Operation: The signal is inserted nose-first into Ground Projector M3 or M4.  The projector is struck smartly on the ground, causing the primer to strike the projector firing pin.  The primer ignites the propelling charge, which projects the signal tail-first for approximately 100 feet.  The signal then reverses itself and reaches an altitude of approximately 600 feet.

High-Bursting Range Signal M27

No picture available

The Range Signal M27 is similar to the projector-type signals, except that it has no tail assembly.  It is fired only from the Ground Signal Projector M1A1.  The signal explodes at the top of its rise, producing a flash and a puff of smoke.

Next Time:  Ground Pyrotechnics (Part 2)

Monday, 19 March 2018

American Projectiles and Explosives - A.A. Flares and Target Identification Bombs

American Projectiles and Explosives

Aircraft Pyrotechnics

A.A. Target Flares

Mk 1 (Obsolete)

Length: 21.4 inches
Diameter: 3.8 inches
Weight: 12 pounds
Burning time: 3 minutes
Intensity: 280,000 candlepower

Use: The flare provides a target for both day and night practice firing of anti-aircraft guns.

Description: The flare consists of an illuminant tube and a cable-container tube made of rocket paper.  These are joined end-to-end under the external metal reinforcing band.  Both ends are closed by chip-board discs held in place with tape.  The cable ring is attached to the snubber cable at the end which protrudes through the cover disc of the flare assembly.  The snubber cable is attached to the base block with staples.
Friction wire is attached to the end of the snubber cable and extends through the primer composition, which is adjacent to the quick match which runs through a cardboard tube in the center of the illuminant.  At the end of the quick-match tube is a firecracker fuse terminating in the first fire composition, which is in contact with the main illuminant charge.

Streaming: The flare may be streamed from any plane from which an aircraft or anti-aircraft target reel can be mounted.

Operation: The flare slides back along the tow cable until the cable ring is stopped by the target release mechanism.  Force exerted on the snubber cable pulls off the end of the cable-container tube, and five solder snubbers are stripped off.  The staples holding the snubber block to the base block are withdrawn by the pull exerted.  Friction wire attached to the end of the snubber block is pulled through the primer.  The flame from the primer ignites the quick match, which in turn ignites the firecracker fuse igniting the first fire charge.  The first fire composition ignites the illuminant.

M50, M77, M78, and M79

No picture available

Length: 22.8 inches
Diameter: 2.5 inches
Weight: 7.13 pounds
Color: White
Intensity: 50,000 candlepower
Length: 23.5 inches
Diameter: 4.25 inches
Weight: 21.1 pounds
Color: Red
Intensity: 207,000 candlepower

Color: Amber
Intensity: 80,600 candlepower

Color: Green
Intensity: 108,500 candlepower

Use: Target Flare M50 has the same use as Target Flare Mk 1.  Target Flares M77, M78, and M79 are assembly markers from which succeeding elements of a forming squadron or group of aircraft can form a target under conditions of poor visibility and congested traffic patterns.

Description and Operation: These are the same as for Target Flare Mk 1.

Remarks: These flares are not under procurement by the Navy at present.

Mk 72 Mod 1

Length: 36 inches
Diameter: 8 and 3/4 inches

Filling: Smoke Composition
-68% Fire Orange dye
-15% Lactose
12% Potassium Chlorate
5% Asbestos shorts
Weight: 45 pounds
Fuzing: 4 pull-type igniters

Construction: This target identification bomb consists of two units, a sheet-steel bomb body casing and a parachute assembly packed in a molded container or pack which is attached to the bomb body by means of four bayonet joints.  The parachute pack houses a four-foot baseball-type parachute, the chute shroud lines, the load cables, the igniter cable, and a static cord which extends out of the top of the pack.  Bomb body casing contains a base block in the tail which incorporates the igniter assembly, 12 vent holes, and four eye bolts.  Load cables are attached to the eye bolts; igniter cable is attached to the pull-type igniters.  Between base block and the nose are the upper and lower candle assemblies.

Suspension: Horizontal suspension is provided by two lugs 14 inches apart, welded onto suspension bands which are bolted to the bomb case.

Operation: Upon release of the bomb, the static cord is retained by the rack or shackle to which it is attached.  The static cord, through a series of short lines inside the pack, removes the molded cover of the pack and pulls the parachute out.  After the parachute is out, the static cord separates from the parachute and is retained by the rack or shackle.  As parachute opens, the igniter cable jerks out the four pull igniters, which ignite the primers.  The primers ignite the firecracker fuze running through the upper candle, which in turn ignites the candle.  The candle burns from the inside toward the outside, evolving colored smoke that permeates holes in the candle case and escapes through vent holes in the bomb case.  The lower candle is ignited by the firecracker fuse about the time the upper candle burns out.
The total burning time is approximately five minutes, during which time the bomb produces a red-orange smoke in sufficient volume to be seen at 15,00 feet for 10 miles, under normal conditions.

Remarks: Target Identification Bomb Mk 72 Mod 1 is used by air-coordinator planes or by scout planes from battleships to pin-point shore targets.  This colored smoke marker is for use over land only, as the bomb does not float.
Greatest accuracy can be obtained by releasing the bomb from altitude of 500 to 1,000 feet.
This bomb can be carried on all external double-suspension racks and shackles.  In addition to the use of this bomb on double-suspension racks or shackles, it can be suspended from the Bomb Adapter Mk 5 Mod 0 (used with Launchers Mk 5 and Mods) when that item is available.  These bombs have been successfully released from external suspension on all types of planes in any flight attitude.  They can successfully withstand catapult launching and arrested landings.

M75A1 and M84A1

Overall length: 53.1 inches
Body length: 39 inches
Body diameter: 8.2 inches
Wall thickness: 0.06 inches
Tail length: 12.9 inches
Tail width: 10.9 inches

Filling: Red iron oxide (hematite)
Weight of filling: 72 pounds
Total weight: 102 pounds

-M75A1 --- M108
-M84A1 --- AN-M147

Construction: Target Identification Bombs M84A1 and M75A1 are identical with the exception of the fuse, and the two bombs are similar in construction to the Chemical Bomb AN-M47A2.  The body is of sheet metal with box-type tail fins welded to the conical section.  The Burster M4 runs through the entire length of the bomb and is closed at the forward end by a closing plug.  A filling plug is placed in the fin cone of the bomb body, to facilitate loading the hematite charge (red iron oxide).  The fuze fits into the forward end of the burster.

Remarks: The Target Identification Bomb M84A1 is intended for release by the lead or "pathfinder" plane to indicate the bomb-release line for bombers in formation when operations are carried out above an overcast and ground targets are not visible.  The bomb was designed to produce a red smoke cloud which would remain at the bursting point for a period of ten minutes under normal air conditions and would be visible for a distance of 15 miles at an altitude of 25,000 feet.

The M75A1 is used for target identification in practice, to mark targets on snow-covered bombing ranges.


M89, M90, M91, M98 and M100

Overall length: 51.8 inches
Body length: 35.8 inches
Body diameter: 10.8 inches
Wall thickness: 0.27 inches
Tail length: 15.7 inches
Tail width: 14.9 inches

Type of filling: 61 pyrotechnic candles (red, green, or yellow)
Weight of filling: 95 pounds
Total weight: 240-265 pounds

Fuzing: AN-M146, M144

Use: The flares are used in emergency night landings.

Construction: The body is a modified 250-pound G.P. Bomb AN-M57 body with a metal closing cup riveted to the base.  An integral booster of four ounces of black powder is placed immediately behind the fuze-seat liner and serves as an expelling charge.  A wooden nose piece fits around this booster, and a steel piston, in turn, is seated in the base of the nose piece.  A steel tube or piston stem is welded through a hole in the piston and extends from the black-powder booster tot he plywood ignition disc in the center of the bomb.  Six wooden thrust members reach from the piston plate to the tail closing cup and serve to transmit stress to this cup without imposing any of the force on the candles.  Felt 1/8 inch in thickness lines the entire interior cylindrical surface of the bomb.  The 61 candles are in two banks of 30 and 31, and have their ignition ends facing toward the quick-match strands stapled on the ignition disc which separates the two banks.

Tail Construction: The tail, in appearance, is a standard box-type tail.  It is attached to the bomb by means of four spring latches fitting into cut-outs in the tail closing cup and can be locked in place by stamped steel strips pivoting over the ends of the springs.

Suspension: Horizontal suspension is provided by standard lugs, 14 inches apart.

Operation: When the aerial-burst fuze functions, the fuze booster ignites the black-powder booster or expelling charge in the bomb.  The force of the expanding gases from the booster, acting through the piston and thrust members, throws off the fin assembly and expels the candles.

Simultaneously, flash from the booster passes through the piston stem to the plywood ignition disc and the quick match, igniting the candles.

Remarks: The bombs are used to form a pattern of red, green, or yellow colored light approximately 100 yards in diameter around or on a target; the light should be visible from altitudes of 25,000 to 35,000 feet day or night.  They are used to spot individual targets, once the general target area has been marked by flares dropped by pathfinder planes.  The explosive charge in the candles M105 is ignited by the flare composition at the end of burning.  These charges serve to prevent any removal of the candles by the enemy, once the candles are on the ground.

The M89 contains 61 Non-Delay Candles M103.

The M90 contains 57 Non-Delay Candles M103 also; two Exploding Candles M105, burning for one minute, and two exploding candles burning for two minutes.

M91 has 16 Non-Delay Candles M103, 15 red 2.75-minute Delay Candles M104, 15 4-minute Delay Candles M104, and 15 5.25-minute Delay Candles M104.

The M98 contains 31 Non-Delay Candles M103, 10 Exploding Candles M105, burning for one minute, 10 Exploding Candles M105, burning for 1.5 minutes, and 10 Exploding Candles M105, burning for two minutes.

The M100 contains Two-Color Combination Candles M104.

Next Time: Smoke Streamer and Photoflash Bombs, and Ground Pyrotechnics (Part 1)

Monday, 12 March 2018

American Projectiles and Explosives - Depth Charges and Slick Markers

American Projectiles and Explosives

Aircraft Pyrotechnics

Day Depth Charge Marker Mk 1 Mods 1 and 2

Length: 11.88 inches
Diameter: 3.46 inches
Weight: 3.5 pounds
Weight of dye: 2.75 pounds
Weight of bursting charge: 30 grams
Effective releasing altitude: Up to 1,000 feet
Visibility: 3,000 yards from deck of ship; 5 miles from aircraft

Use: The marker is used to indicate the initial point of contact with submarines and provide a reference point for further search and attack during day operation.

Description: The marker consists of a circular wooden block on which is mounted a grenade-firing mechanism with a 15-second delay.  Fluorescein dye is contained in two cylindrical paper cans, one attached to each flat side of the wooden block; and a celluloid tube containing the black-powder bursting charge is attached to the delay element and extends through the wooden block into the paper cans.  The dye is rusty red in color when dry, but a water solution of the dye is yellow-green.

Operation: The operator clasps the marker firmly in one hand, being sure that the release lever is held against the body of the marker.  With the other hand, he pulls the safety ring which is attached to the safety cotter pin and launches the marker by throwing it over the side.  When the marker is released, the spring-loaded striker forces the release lever off.  The striker, rotating about a hinge pin, hits the primer that ignites the 15-second delay fuze.  The delay gives the marker sufficient time to reach the water and float on the surface, and then ignites the bursting charge.  The gases evolved from the charge burst the dye containers and spread the dye on the water, forming a yellow-green slick about 40 feet in diameter.  The slick lasts for 45 to 60 minutes.

Night Depth Charge Marker Mk 2

Length: 7 inches
Diameter: 5 inches
Weight: 2.5 pounds
Effective releasing altitude: Up to 3,000 feet
Visibility: 4 miles from deck of ship; 10 miles from aircraft

Burning time: 55 minutes
Ignition time (after impact): 70-90 seconds

Use: The marker is employed to indicate the initial point of contact with submarines and provide a reference point for further search and attack during night operations.

Description: The marker is a sealed, cylindrical, metal container that has a centrally located tube, sealed on both ends by tear strips with a pull ring attached, and containing calcium phosphide.  The main charge is calcium carbide that surrounds the central tube and is held in one end by a screen.  This produces a concentration of weight at one end and allows the marker to float in an upright position.

Operation: After the two tear strips are pulled off, the marker is launched by throwing it overboard.  Water enters through the small calcium carbide (producing an inflammable gas, acetylene) and with the calcium phosphide (producing a spontaneously ignited gas, phosphine).  Both gases escape from the small holes in the top and ignite within 70 to 90 seconds after impact with the water.  In extremely cold weather, the ignition delay may be somewhat longer.  The resulting flame is about nine inches high.  If it should be put out by rough water, the gases will ignite again.

Slick Marker Cartridge AN-Mk 1

No picture availabe

Length: 3.8 inches
Diameter: 1.5 inches
Muzzle velocity: 300 feet/sec
Weight of dye: 28 grams

Use: This marker is used primarily to provide reference points for aircraft engaged in anti-submarine warfare.

Description: The cartridge is composed of a shotgun-type case containing a primer, a black-powder propelling charge, and the projectile.  The projectile has a thin aluminum case and contains 28 grams of fluorescein dye and a black-powder bursting charge initiated by a Bickford-type fuze.

Launching: The marker cartridge is fired in the Pyrotechnic Pistol AN-M8, which may be held in the hand or mounted in the Mount M1.

Operation: When the cartridge is fired, the black powder in the head of the case propels the projectile from the pistol and at the same time ignites the Bickford fuze.  The fuze burns for about eleven seconds before igniting the bursting charge which expels the fluorescein dye out into the water.  The projectile has a positive buoyancy and will remain near or at the surface until a small, bright green slick is created.

Remarks: This cartridge should not be fired from altitudes greater than 500 feet, because the cartridge must be in the water when it bursts.

Slick Marker AN-M59

No picture available

Length: 10.875 inches
Diameter: 3.375 inches
Weight: 2.9 pounds

Use: This is the standard all-purpose sea marker for daylight use: to provide reference points; to aid in determining drift; and to provide practice bombing targets on water.

Description: This marker consists of a paper composition case filled with a  fluorescein dye.  It is protected by a cylinder of papier-maché, which does not interfere with its function.

Launching: The marker is dropped by hand from a plane.

Operation: Upon impact with water, the case shatters and the dye spreads upon the surface.

Army Flares

M8 and M8A1

No picture available
Length: 25.5 inches
Diameter: 4.25 inches
Weight: 18 pounds
Color: Yellow
Intensity: 850,000 candlepower
Burning time: 3 minutes
Rate of fall after ignition: 500 feet/min

Use: The flares are used in emergency night landings.

Description: Each flare consists of a cylinder containing an unshaded candle.

Operation: Army Flares M8 and M8A1 are similar in operation to the Flares An-M26, except that the hang wire pulls the parachute directly from the case.

Remarks: The M8 is similar to the M8A1, except that the latter flare burns with a white light approximately 250,000 candlepower.

M9 and M9A1

Picture seen above

Length: 13.8 inches
Diameter: 2 inches
Weight: 1.9 pounds
Color: Yellow
Intensity: 60,000 candlepower
Burning time: 1 minute
Rate of fall after ignition: 400 feet/min

Length: 15.05 inches
Weight: 2.1 pounds

Use: This flare was designed to satisfy the requirements for a small parachute flare for reconnaissance.

Description: The flare consists of a cylinder containing a candle, designed to be projected with the Pyrotechnic Pistol AN-M8.

Operation: The flare is discharged from the pistol and the delay fuse is ignited.  The fuse burns for 2.5 seconds and ignites the expelling charge, which expels the candle and parachute, simultaneously igniting the candle.

Remarks: This flare is not procured by the Navy.

M24 (Obsolete)

Picture seen above

Length: 37 inches
Diameter: 8 inches
Weight: 47 pounds
Color: Yellow
Intensity: 800,000 candlepower
Burning time: 3 minutes
Releasing altitude: 2,500 to 3,000 feet
Speed of release: Not over 200 mph
Rate of fall after ignition: 700 feet/min

Use: The flare is a substitute standard for night observation and bombardment.

Description: It consists of a simple cylinder without hemispherical nose or tail fins; otherwise, it is similar throughout to the AN-M26, without the nose time fuze.

Operation: The flare is similar to the AN-M26 except that the hang wire acts directly to pull the parachute from the flare case.

Remarks: This flare was not procured by the Navy.

M6 and AN-M26

Picture seen above

Length: 50 inches
Diameter: 8 inches
Weight: 53 pounds
Color: White light
Intensity: 800,000 candlepower
Burning time: 3 to 3.5 minutes
Releasing altitude: 4,000 to 25,000 feet
Rate of fall after ignition: 700 feet/min

Use: These flares are used to provide illumination for night bombardment; also may be used to blind anti-aircraft defenses.

Description: The flare is enclosed in a metal cylindrical case with a rounded nose and tail fins.  In the nose is a mechanical time fuze.  The tail end is closed with a shipping cover that has a handle attached and sealed by a strip of tape.  The case is equipped with two suspension lugs 14 inches apart.

Operation: When the flare is dropped, the arming wire is pulled, allowing the vanes of the nose fuze to rotate.  The hang wire is retained and pulls off the cover of the stabilizing-sleeve compartment.  As the flare continues to drop, the tear wire and tear-wire cord pull out the stabilizing sleeve, and the cover-lock cord attached to the shrouds of the stabilizing sleeve unlocks and pulls out the cover lock.  When the sleeve is fully extended, the tear wire breaks, allowing the flare to fall free, stabilized in flight by its fins and stabilizing sleeve.

When the nose fuze functions, the gases of the black-powder booster force the releasing-cup cover out of the detachable cover, releasing the retaining pins from the groove in the flare case and freeing the detachable cover.  As the detachable cover is pulled out by the stabilizing sleeve, a pull-out cord pulls out the parachute.  when the parachute opens, the flare stops with a  jerk, breaking the pull-out cord (which allows the stabilizing sleeve assembly to fall free) and pulling the entire flare assembly out of the flare case (which then falls away).  The sudden stop also pulls the friction wires through the igniters, starting the six-second delay through the center of the candle, which allows full opening of the parachute.

The shock caused by the opening of the parachute is taken by the shock absorbers, made of copper tubing in a spiral or coiled shape.  they straighten out in absorbing the shock.  After the parachute is opened, the delay ignites the first fire, which ignites the candle.  When the first fire is ignited, the gases formed by burning force the rib retainer down, and the spring-loaded ribs jump out, opening the glass-cloth shade.

Remarks: The Flare AN-M26 can be dropped at air speeds up to 240 knots, but above that the stabilizing sleeve is apt to tear away.  The Flare M26 cannot be dropped at air speeds greater than 130 knots, for the same reason.

Next Time: A.A. Flares and Target Identification Bombs