The M69 incendiary bomblet was used in

air raids on Japan Air raids conducted by Allied forces on Japan during World War II caused extensive destruction to the country's cities and killed between 241,000 and 900,000 people. During the first years of the Pacific War these attacks were limited to the ...

and China during

World War II World War II or the Second World War, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 1945. It involved the vast majority of the world's countries—including all of the great powers—forming two opposing ...

, including the

firebombing of Tokyo The was a series of firebombing air raids by the United States Army Air Force during the Pacific campaigns of World War II. Operation Meetinghouse, which was conducted on the night of 9–10 March 1945, is the single most destructive bombing ...

in 1945. It was created by the Standard Oil Development Company, whose work was funded by the

Office of Scientific Research and Development The Office of Scientific Research and Development (OSRD) was an agency of the United States federal government created to coordinate scientific research for military purposes during World War II. Arrangements were made for its creation during May 1 ...

. They were nicknamed "Tokyo calling cards". The M69 was a plain steel pipe with a hexagonal cross section in diameter and long. It weighed about . The bomblet used

napalm Napalm is an incendiary mixture of a gelling agent and a volatile petrochemical (usually gasoline (petrol) or diesel fuel). The name is a portmanteau of two of the constituents of the original thickening and gelling agents: coprecipitated alu ...

as an incendiary filler, improving on earlier designs which used thermite or magnesium fillers that burned more intensely, but were less energy- and weight-efficient, and were easier to extinguish. In Germany they were filled with jellied oil and dropped in clusters of 36 in the non-aerodynamic M19 bomb. Over Japan they were used in clusters of 38 as part of the finned E-46 'aimable cluster', which opened up at about . After separation, each of the 38 M69s would release a 3-foot (1 m) cotton streamer to orient its fuze downward. Upon hitting a building or the ground, the timing fuze burned for three to five seconds and then a small explosive charge ( black powder in the standard M-69 type deployed operationally during WW2,

white phosphorus Elemental phosphorus can exist in several allotropes, the most common of which are white and red solids. Solid violet and black allotropes are also known. Gaseous phosphorus exists as diphosphorus and atomic phosphorus. White phosphorus White ...

in a later modification, the M-69X, which did not see wide use) ignited and propelled the incendiary filling up to 100 feet (30 m) in several flaming globs, instantly starting intense fires. It was tested against typical German and Japanese residential structures at Japanese Village and

German Village German Village is a historic neighborhood in Columbus, Ohio, just south of the city's downtown. It was settled in the early-to-mid-19th century by a large number of German immigrants, who at one time comprised as much as a third of the city's ...

, constructed at

Dugway Proving Ground Dugway Proving Ground (DPG) is a U.S. Army facility established in 1942 to test biological and chemical weapons, located about southwest of Salt Lake City, Utah, United States, and south of the Utah Test and Training Range. Location Dugway P ...

Utah Utah ( , ) is a state in the Mountain West subregion of the Western United States. Utah is a landlocked U.S. state bordered to its east by Colorado, to its northeast by Wyoming, to its north by Idaho, to its south by Arizona, and to it ...

, in 1943. The M69 was the most successful incendiary in the tests. Against Japan, the M69 was carried in the bomb bay of the Boeing B-29 Superfortress, with a typical load containing 40 cluster bombs, a total of 1520 M69 bomblets. As they were very useful in China at

Hankou Hankou, alternately romanized as Hankow (), was one of the three towns (the other two were Wuchang and Hanyang) merged to become modern-day Wuhan city, the capital of the Hubei province, China. It stands north of the Han and Yangtze Rivers whe ...

, the bombs were very effective in setting fire to Japanese civilian structures in mass

firebombing Firebombing is a bombing technique designed to damage a target, generally an urban area, through the use of fire, caused by incendiary devices, rather than from the blast effect of large bombs. In popular usage, any act in which an incendiary d ...

raids starting in February 1945 against Kobe. In the first ten days of March 1945, raids with the M69 and M47, extensive damage was done to Tokyo, to Nagoya, to Osaka, and to Kobe.World Battlefronts: Ten-Day Wonder
''Time'', Mar. 26, 1945

References

{{reflist Cluster munition Incendiary weapons Aerial bombs of the United States

See also

References