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  The staples holding the snubber block to the base block are withdrawn by the pull exerted.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)

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