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"Incendiaries" from Tactical and Technical Trends

The following intelligence report on WWII incendiaries was originally published in Tactical and Technical Trends, No. 14, Dec. 17, 1942.

[DISCLAIMER: The following text is taken from the U.S. War Department publication Tactical and Technical Trends. As with all wartime intelligence information, data may be incomplete or inaccurate. No attempt has been made to update or correct the text. Any views or opinions expressed do not necessarily represent those of the website.]


The following article is a reprint of "Chemical Warfare Intelligence Bulletin 3" emanating from the office of the Chief of Chemical Warfare. It comprises an excellent summary of information on developments in incendiary munitions, and as such would be of interest to readers of Tactical and Technical Trends.

*        *        *

The past year has seen changes in design, construction, and tactical use of incendiaries on the part of all warring nations. Each of the Axis nations has developed new types of aerial bombs and incendiary munitions, with Germany taking the lead. This bulletin provides information on these changes, with a chart which gives a late compilation of all known types of enemy incendiary bombs.

a. Germany

The outstanding incendiary developed by the Germans during the past 12 months has been a combination of an antipersonnel and incendiary bomb. Using the 1-kilogram (2.2 lbs.) incendiary as a base, they removed the explosive charge from the tail and added a steel extension to the nose, containing a much more powerful charge (at first thought to be TNT but later believed to be a picric acid derivative) and fuze. This change was due to the British having perfected a plan for, combatting the regular oil, thermite, or magnesium incendiaries and to the civilian personnel having become thoroughly trained in defense measures.

The effect is essentially as follows: If fire wardens attempted to put out the fire as in the case of ordinary incendiary bombs, the explosive nose -- times with a fuze to go off in from 1 to 5 or more minutes -- would catch them unawares. In some cases the bomb might break in half and the two portions could roll in different directions; thus, while fighting the incendiary section in one location, the fire warden would be endangered by the explosive portion, possibly lying unnoticed in a dark corner. With a lethal velocity 50 feet from the point of explosion, this new-type bomb has meant a delay of 5 to 7 minutes in effective defense measures.

Another type recently developed contained a canister of small incendiary units scattered by a large high-explosive charge. As the bomb bursts, it throws out about 60 metal containers with a thermite-type filling, and 6 pre-ignited firepots of the magnesium electron type. Immediately thereafter the TNT detonates. The weight of this incendiary bomb (110 lbs.) insures penetration, and the explosive charge (16 pounds of TNT) produces a definite demolition effect, wrecking partitions, doors, ceilings, flooring, etc.

A 50-kilogram (110-pound) bomb, with a filling containing 10 percent rubber and 4 percent phosphorus in an oil gel base, has been used with questionable success as an incendiary agent, phosphorus burns occasionally being inflicted on personnel. Some pieces of gel remain exposed to the air a considerable time without catching fire, while others start smoking and ignite after only a few minutes.

[Initial information on the 3 incendiaries above appeared in Tactical and Technical Trends No. 6, p. 21.]

b. Italy

While to date not actively engaged in any large-scale utilizations of incendiary bombs, the Italians have produced a 1-kilogram type similar to the German, and in addition have developed two new ones. One of these, a 43-pound type, may be mistaken for the Italian 50-kilogram torpedo-type bomb; the other, a 62-kilogram bomb, carries a filling of 54 pounds of thermite.

c. Japan

The chart shows graphically several types of Japanese incendiary bombs which depend mainly on thermite, phosphorus, and oil. This may indicate a magnesium shortage. They have experimented also with the use of parachute-borne incendiaries, with action delayed in some cases up to 6 hours. One type used in the Philippines was made of a pasteboard composition. Stains and odors found near points of explosion indicated that they contained picric or sulphuric acid. However, the incendiary effect was limited.

[See Tactical and Technical Trends No. 12, p. 17 for information on incendiaries dropped on Rangoon by the Japanese.]

Two incendiaries were dropped by an unidentified plane on Mt. Emily, near Brookings, Oregon, in September 1942. Parts and fragments of one were recovered. The fuze had Japanese characters stamped on it; apparently the bomb was 125 to 150 pounds, with a nose of metal twice as thick as the body; it was evidently not a production job, but an adaptation from a mortar shell. Some 35 or 40 triangularly shaped pellets with a round hole in the center of each were recovered. They appeared to be of a hard rubber composition impregnated with particles of magnesium; it is also possible that a thermite mixture was in the bomb. (Note: In some cases this filling is believed to contain additional chemicals and organic materials, which may appear in later type bombs.)

See chart, next page, for other German, Italian, and Japanese incendiary bombs.

[Enemy Incendiary Bombs]
[click image to enlarge]

d. Other Incendiary Munitions

(1) Grenades

Under this heading is grouped information regarding frangible grenades ("Molotov Cocktails"), antitank grenades, and similar weapons.

The German "T B" hand-thrown prussic acid grenade is a glass cylinder approximately 4 inches in diameter, packed in sawdust in a cardboard container, and the container packed in sawdust again inside a metal canister.

The Japanese have a similar type, filled with prussic acid, several cases of these grenades having been washed up on the beach in the beginning of the Malayan campaign. As HCN may inflame, it must be considered as an incendiary as well as a toxic agent.

From Russia have come unconfirmed reports of the use by the Germans of incendiaries (frangible grenades dropped from planes?) to set fire to the high grasses of the steppes.

An Italian incendiary grenade, devised for close defensive work against tanks and armored vehicles, consists of a quart of gasoline in a glass bottle fitted with a metal cap. An igniter fuze, match, and wooden handles are attached to the side of the bottle. For distances of 65 feet or more, a safety device is utilized which operates after a long trajectory.

The Japanese developed a grenade in the form of a liquid-filled beer bottle stamped "B Kirin Brewery Co. LTD." The fluid is essentially coal tar. This bottle is equipped with fuze, safety lid, and safety pin.

(2) Shells

The German Schwere Wurfgerät 40, mounted on an armored half-track vehicle for field use, is a weapon for firing both high explosive and incendiary ammunition. The latter is reported to be as follows: weight of projectile, 174 pounds; filling, 11 gallons of oil; markings, green and yellow band. The projectile is reported to be a rocket type, fired electrically, with a range of over 2,000 yards.

[See Tactical and Technical Trends No. 8, p. 28 and No. 12, p. 12 for additional information on this weapon.]

(3) Disks

Samples of incendiary disks, used by the Germans to fire crops, woods, fields, etc, have been examined. They appear to be made of sponge rubber -- colored bright yellow -- and catch fire spontaneously, forming a black oily substance. Roughly oval in shape, 3/8-inch thick (the largest being 9 by 16 inches and the smallest 4 by 3 inches), they are harmless when wet, and may be moved in this condition to a safe place where they can dry and burn themselves out.

(4) Tracer Bullets

A 13-mm (0.514-inch) incendiary tracer bullet used by the Italians is similar in appearance to their 13-mm explosive bullet, except that the body is colored blue instead of red.


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